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Volkan Kilinc, [Ryoma Hayakawa](https://orcid.org/0000-0002-1442-8230), Yusuke Yamauchi, [Yutaka Wakayama](https://orcid.org/0000-0002-0801-8884), [Jonathan P. Hill](https://orcid.org/0000-0002-4229-5842)

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[Nanoporous Dna Field Effect Transistor with Potential for Random‐Access Memory Applications: A Selectivity Performance Evaluation](https://mdr.nims.go.jp/datasets/c84807ed-52e2-4544-adae-5795f9027573)

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Nanoporous Dna Field Effect Transistor with Potential for Random‐Access Memory Applications: A Selectivity Performance EvaluationRESEARCH ARTICLEwww.advsensorres.comNanoporous Dna Field Effect Transistor with Potential forRandom-Access Memory Applications: A SelectivityPerformance EvaluationVolkan Kilinc,* Ryoma Hayakawa, Yusuke Yamauchi, Yutaka Wakayama,and Jonathan P. Hill*Methods to encode digital data items as strands of synthetic DNA followed byselective data retrieval have been demonstrated. However, these initiallybio-oriented processes remain slow and not optimized. DNA field-effecttransistor (DNA-FET) is studied here as a possible random-access memory(RAM) device for simple, selective and rapid ssDNA fragment retrieval usedas data pool identifier. The DNA-FET is based on a co-planar Au-gated fullyorganic transistor appended with short single-stranded DNA (ssDNA) probesbearing a blocking molecule to prevent partial hybridization and achieve nearperfect selectivity for short length ssDNA (up to 45 nt). Examination oftransconductance of the novel active layer incorporating a DNA nanoporearchitecture reveals enhanced binding site accessibility. This, in turn,facilitates discriminatory hybridization, particularly in the physical retrieval ofshort-length ssDNA from a competitive, concentrated ssDNA backgroundpool consisting of nine different sequences, with at least one nucleotidedifference. The DNA-FET exhibits rapid operation (9 min) in the millivoltrange, low detection limit (sub-femtomolar), high selectivity and reusability.Considering the straightforward concept, near error-free identificationcapacity and hypothetically outstanding scalability, the DNA-FET describedhere has potential as a foundation for further exploration of advanced RAMtechnology in the DNA data storage process.1. IntroductionThe International Data Corporation has estimated that world-wide by 2025 the quantity of data stored electronically will reach aV. Kilinc, R. Hayakawa, Y. Yamauchi, Y. Wakayama, J. P. HillResearch Center for Materials Nanoarchitectonics (WPI-MANA)National Institute for Materials Science (NIMS)Namiki 1-1, Tsukuba, Ibaraki 305-0044, JapanE-mail: kilinc.volkanyunus@nims.go.jp; jonathan.hill@nims.go.jpThe ORCID identification number(s) for the author(s) of this articlecan be found under https://doi.org/10.1002/adsr.202300176© 2024 The Authors. Advanced Sensor Research published byWiley-VCH GmbH. This is an open access article under the terms of theCreative Commons Attribution License, which permits use, distributionand reproduction in any medium, provided the original work is properlycited.DOI: 10.1002/adsr.202300176volume of over 175 zettabytes[1] (in 2007,the value was only 0.29 zettabytes[2]).With the rapid introduction of new data-intensive technologies including the In-ternet of Things, artificial intelligence,blockchains and metaverses, even moredata is expected to be generated so thatdata storage (volume and rates) might be-come a limiting factor in the applicationof those technologies. Furthermore, datamust be stored to optimize its securityand accessibility, which will also be in-creasingly challenging with exponentialincreases in data volumes. Current datastorage devices are based on disk andsolid-state drives of limited durability (30years) and data storage capacity whose de-velopment is not keeping pace with cur-rent or future data growth rate require-ments. Therefore, radically new storagemedia having high data density and dura-bility characteristics should be sought.Natural systems use deoxyribonucleicacids to store vast amounts of informa-tion, and it is an important paradigmof data storage based on several criticaladvantages. It has an extremely dense data storage capacity,[3] ischemically stable over several centuries under relatively harshconditions, no power source is required to maintain data,[4] andit is abundant. Researchers have already successfully establishedthe potential of DNA as a storage medium by storing digital dataY. YamauchiAustralian Institute for Bioengineering and Nanotechnology (AIBN)The University of QueenslandBrisbane, QLD 4072, AustraliaY. YamauchiDepartment of Materials Process Engineering, Graduate School ofEngineering, Nagoya University, Furo-cho, Chikusa-kuNagoya UniversityNagoya, Aichi 464–8603, JapanAdv. Sensor Res. 2024, 3, 2300176 2300176 (1 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbHhttp://www.advsensorres.commailto:kilinc.volkanyunus@nims.go.jpmailto:jonathan.hill@nims.go.jphttps://doi.org/10.1002/adsr.202300176http://creativecommons.org/licenses/by/4.0/http://crossmark.crossref.org/dialog/?doi=10.1002%2Fadsr.202300176&domain=pdf&date_stamp=2024-02-02www.advancedsciencenews.com www.advsensorres.comincluding text, images, music, classified information, etc.[5–8] Theapplication of DNA for data storage is based on five steps: (1) dataencoding (convert binary data to A, T, C, G data), (2) synthesis andstorage of the corresponding DNA sequence, (3) random accessof the data by retrieving the corresponding sequence in a pool ofDNA, (4) sequencing of the retrieved DNA and (5) data decod-ing (A, T, C, G data to binary data). To enable DNA data storagetechnologies for archiving or for day-to-day uses, and to reduceits cost,[9] progress is required at all of these five steps. For exam-ple, for Step (2), enzymatically-driven DNA synthesis is a verypromising method offering high coupling efficiency with bet-ter reliability and rates than traditional phosphoramidite-basedtechniques.[10–12] Several new companies have already been es-tablished working to improve DNA synthesis yield.[13] Also, asan example of what might be achieved using DNA sequencing, itis now possible to sequence an entire human genome in a singleday for only $1000.[14–16] For reference, in 2003 it took thirteenyears and almost three billion dollars to complete the HumanGenome Project.[15] Such progress has been made possible usinghigh-throughput sequencing by Illumina[17] and nanopore se-quencing from Oxford Nanopore Technologies.[18–20] Processingmethods with concurrent synthesis and sequencing of DNA[21]are also promising despite their increased complexity.One of the critical steps in the use of DNA as an efficient datastorage medium involves random access of the data. In fact, thephysical retrieval of a requested data item contained in a spe-cific DNA sequence from a DNA pool is required to be rapid anderror-free. DNA “files” are retrieved conventionally using poly-merase chain reaction (PCR):[21] the selected file to be read-outfrom the pool possesses a sequence that binds to a particular de-signed primer. When the primer is added, amplification of thetarget sequence occurs but the sub-pool is then useless for furtheroperations due to the resulting overloading.[22] Non-target DNAsequences can also cross-talk or interfere with the primer leadingto retrieval of unwanted files, therefore compromising the data.To overcome these issues, certain modifications have been madebased largely on chemical modification of the primers (for in-stance, by appending magnetic beads) leading to selective physi-cal extraction of the desired information from the DNA pool with-out compromising the original database.[23,24] A direct random-access approach not involving PCR amplification has also beendeveloped. Initial encapsulation of DNA sub-pools in silica par-ticles labelled with short ssDNA at their surfaces is followed bytheir sorting by using fluorescent ssDNA probes.[25]To enable the massive up-scaling of addresses contained inDNA, a PCR-free method is required.[26] DNA-FET technology isan interesting alternative technology for the purpose of random-access memory. By using this technique, base-pairing interac-tions between complementary sequences near the surface canbe measured and transduced according to generation of electri-cal signals. Nevertheless, this technology faces limitations whendealing with longer DNA lengths and appears unconventionalfor direct data access, given that data are encoded and storedwithin a pool of long double-stranded DNA (dsDNA). In fact, thehybridization event, which is only observable with ssDNA pair-ing, can be screened by charges near the surface (Debye screen-ing effect[27]) resulting in reduced sensitivity and increased error-rates of the device. To overcome this limitation and make DNA-FET suitable as RAM, a potential approach involves consideringshort ssDNA as a signature component for a designed data pool.Consequently, the identification of a specific ssDNA in a compet-itive and concentrated medium to mimic large dataset DNA poolwould then enable the identification of the corresponding datapool.In recent research advances based on DNA-FET, the detectionof free-DNA in biological samples for cancer diagnosis has beenestablished. It promises performance far superior to the exist-ing sensing techniques with sensitivity to attomolar level[28–31]and high scalability with particular Complementary Metal OxideSemiconductor (CMOS)-based FET[32] regardless of the selectiv-ity parameter of the device, which is not crucial in this applica-tion. However, for DNA-RAM applications, the selectivity param-eter of DNA-FET is critical for operation to enable low error rates.While recent advances have been made in improving the selectiv-ity of DNA-FETs,[33–37] none of them provide high selectivity un-der competitive conditions in concentrated solution. A DNA-FETcapable of identifying a diverse DNA sequence with high selectiv-ity and sensitivity in a complex background pool containing dif-ferent DNA sequences (to reduce error-rate and measurementsrepeatability), with fast operation, reusability with the same data-set and simple scale-up is therefore required to overcome the in-tricate retrieval step of the DNA data storage process.Here we propose an approach based on DNA-FET for nearerror-free detection of short ssDNA used as a data pool signa-ture component in a concentrated competitive DNA pool. TheDNA-FET is based on a poly(3-hexyl) thiophene (P3HT) semicon-ducting layer and co-planar to the channel area Au-gate electrodetuned with short ssDNA (23-45 nt) probes bearing a blockingmolecule to avoid partial hybridization. We show here that thisconformational ssDNA active layer allows access to the targetedssDNA sequence in a highly concentrated pool of nine competi-tive ssDNA sequences with high discrimination (down to one nu-cleotide difference), rapid operation (9 min), and reusability withthe same data-set. Various sequences of ssDNA probe were testedand the results indicate high scalability potential conditioned bycombining several DNA-FETs. Topographic analysis by scanningelectron microscope (SEM) reveals nanoporous structures whichaffect the selectivity of the DNA-FET. Analysis of transconduc-tance based on transistor characteristics and surface plasmonresonance measurements confirm the benefit of the presenceof the blocking molecule appended at the ssDNA probe for thehigher binding site accessibility discrimination in the physical re-trieval of short length ssDNA in a competitive pool. The promis-ing initial findings indicate the potential for utilization of DNA-FET in the random-access stage of the DNA data storage process(Figure 1).2. Experimental Section2.1. MaterialsSolvents and other materials were obtained from Tokyo KaseiChemical Co. Ltd, Sigma-Aldrich Chemical Co. Ltd, Fujifilm-Wako Chemical Co. Ltd., or Nacalai Tesque Chemical Co. Ltd.And were used as received. Field-effect transistors (FET) withcoplanar gate and interdigitated gold electrodes with 30 μmband/gap dimensions were obtained from Metrohm DropSens.Adv. Sensor Res. 2024, 3, 2300176 2300176 (2 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.comwww.advancedsciencenews.com www.advsensorres.comFigure 1. Concept of DNA-FET for data retrieval. Process for the use of DNA as a data storage medium. First, data to be stored is encoded in nucleicdata, then it is synthesized and stored in DNA data pool containing multiple nucleotide sequences. Corresponding DNA sequence to be accessed fromthe pool is retrieved and sequenced followed by a data decoding step (A, T, C, G data to binary data). In this work, DNA-FET is proposed to be used atthe step of retrieving short ssDNA as signature component of DNA data pool.ssDNA were all purchased from IDT (see Table S1 and Table S2,Supporting Information for details).2.2. Semiconducting Layer FormationRegioregular P3HT (Mw = 27000–45000) was dissolved in 1,2-dichlorobenzene at concentration 1 mg mL−1 and deposited byspin-coating (1 μL, 600 rpm for 10 s then 2000 rpm for 50 s) on thedrain-source channel area of the interdigitated electrodes. Afterannealing at 80 °C for 15 minutes, sulfuric acid (3 μL, 50% w/v)was deposited on the drain-source channel area and left to standfor 10 minutes. The FET was then carefully rinsed with deionized(DI) water and dried at 80°C for 30 minutes. P3HT (1 μL, c =6 mg mL−1 in 1,2-dichlorobenzene) was deposited on the channelarea using the same conditions with subsequent annealing undervacuum at 80 °C for 1 h.2.3. ssDNA Selective Layer FormationTypically, prior to deposition, ssDNA was diluted in PBS X-0,01(100 μL) and mixed with dithiothreitol (100 μL at 20 μM) at 45 °Cfor 10 minutes to cleave dithiol bonds. The solution was thenpurified by passing through a NAP-10 column (Cytiva). ssDNAprobe solution (30 μL, 1.33 μM) was dropped onto the gate elec-trode of the FET followed by incubation at 25 °C for 24 h. The FETwas rinsed with DI water then incubated in DI water at 80 °C for2 h to remove any impurities.2.4. Detection MeasurementsCompeting ssDNA data units (up to eight) were mixed in a poolsolution at a total concentration of 10−5 M in PBS X-0,01. An-other pool solution containing target ssDNA spiked at concentra-tion 10−5 M with competing ssDNA data units (up to eight) alsobeing prepared (see Tables S1,S2, Supporting Information fordetails about the DNA sequences). The P3HT-semiconductinglayer-modified-FET was placed in a custom built polychlorotri-fluoroethylene (PCTFE) well and PBS X-0,01 (60 μL) was added,covering both the sensing and transducer part of the device. After10 minutes, five cycles (4 minutes each) of ID/VG measurements(Keysight B2912B) were undertaken at VG = 0.6 V or 0.2 V to−0.6 V with VD = −0.5 V. After rinsing with DI water, compet-ing ssDNA solution (60 μL) was added at the same point. After10 minutes, the gate electrode was rinsed with DI water and PBSX-0,01 was added and the ID/VG measurements were repeated atleast three times. The identical procedure was also repeated forthe target DNA spiked competing ssDNA solution.2.5. Imaging2.5.1. SEM ImagingSurface morphology of obtained ssDNA structure was investi-gated by scanning electron microscopy (SEM S-4800 HitachiCo.Ltd) operated at 5–10 kV.2.5.2. AFM ImagingAFM (SPI-4000, Hitachi High Technologies) with supersharp tip(SSS-NCHR from NanoSensors) was used in tapping mode (T =3.8 μm, W = 28 μm, L = 125 μm, C = 29 N/m, f = 283 kHz).2.6. Capacitance MeasurementsTransistor tester LCR-TC1 was used to measure the capacitanceat the interfaces between the ssDNA functionalized gate elec-trode/electrolyte and the semiconducting channel/electrolyte.2.7. SPR MeasurementsNanoSPR9 surface plasmon resonance spectrometer (NanoSPRLLC, Milwaukee, USA) with two microchannels was used inpulse mode. Gold-coated substrates provided by the same com-pany were washed with ethanol and DI water prior to the ssDNAselective layer formation protocol. Equation 1 was used to extractreflectivity difference ΔR from the raw data. R was the measuredreflectivity, R0 was the reflectivity of the ssDNA layer without an-alyte, Reqwas the reflectivity of the ssDNA layer at equilibriumwith the analyte.ΔR =(1 −R − ReqR0 − Req)∗ 100 (1)Adv. Sensor Res. 2024, 3, 2300176 2300176 (3 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.comwww.advancedsciencenews.com www.advsensorres.comFigure 2. Structure and characterization of the DNA-FET. a) Structure of DNA-FET. Interdigitated gold source-drain electrodes of 30 μm band/gapdimension channel are embedded in two intercalated P3HT layers with sulfuric acid at the interlayer, on flexible polystyrene support. Coplanar gateelectrode is grafted with ssDNA probe (23 nt) bearing fluorescein amidite capping molecule by thiol-Au bonding. b) Image of the commercially availableFET showing the gold gate electrode in coplanar configuration. c) ID/VG characterization, with VD applied from 0 V to –0.5 V, 0,1 V step. d) ID/VDcharacteristic curve with VG applied from 0.2 V to −0.5 V at 0.1 V intervals. e) Output curve (VG = −0.5 V) with/without sulfuric acid interlayer addition.The acid treatment is modifying the local organization of the P3HT layer near the interface allowing to skip the step of high annealing at 150 °C.3. Results and Discussion3.1. Design of the DNA-FETThe DNA-FET device is composed of two parts: the sensing areacomprising active ssDNA probes capable of interacting with thetarget ssDNA sequence and the transducer area composed of asemiconducting layer responsive to electrical modulation occur-ring in the sensing area (Figure 2a). For the application of DNA-FET in DNA data access processes, it is critical to enhance the se-lectivity of the active ssDNA layer in the presence of a competitivebackground. Therefore, a simple easy-to-reproduce procedure forthe transducing part is especially required and is introduced inthis work. For this purpose, a procedure involving a commer-cially available FET structure with Au based gate electrode in co-planar configuration (Figure 2b) and well-known semiconduct-ing polymer, P3HT, has been used. P3HT is an organic p-typesemiconducting polymer whose hole mobility (0.1 cm2 V s−1)is strongly affected by its molecular organization, especially therelative conformations of 3-hexylthiophene units.[38] Optimumhole mobility is usually achieved by applying an annealing stepat 150 °C,[39] which promotes organization in films due to a pref-erence for non-coplanarity of 3HT units. However, in this work,high temperature annealing of the FET was not possible since apolystyrene-based material is used as a substrate necessitating anannealing temperature limit of 80 °C to avoid destruction of thedevices. To ameliorate for the loss in the semiconducting layerperformance, a sulfuric acid layer deposited at the interface oftwo P3HT layers has been applied (Figure 2e). This techniquepromotes the local reorganization of 3HT units in the P3HTlayer[40] circumventing the necessity of the high temperature an-nealing process. AFM topographic images indicate a rough (Ra =20,4 nm) “patchwork” top P3HT layer of around 40 nm thickness(see Figure S2e,f, Supporting Information). Transfer and out-put curves obtained by transistor measurements (Figure 2c,d.)show typical behavior for p-type FET. The optimized FET (seeFigure S1, Supporting Information) exhibits reproducible perfor-mance up to 40 measurement cycles with low leakage currents(see Figure S2a,b, Supporting Information), acceptable hystere-sis, and works at low voltage resulting in low power consumption.While the performance of the designed FET may not be excep-tional, its simplicity makes it well-suited for a comparative studywithin the scope of this workFor efficient and error-free ssDNA data unit retrieval by DNA-FET, selective detection in a competitive background by activessDNA probes is required. In conventional ssDNA probe layerimplemented in FET, partial hybridization with interfering tar-get ssDNA sequences can affect the transduced electrical signalAdv. Sensor Res. 2024, 3, 2300176 2300176 (4 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.comwww.advancedsciencenews.com www.advsensorres.comFigure 3. ssDNA layers functionalization: Nanopore-DNA-F method. a) Purified ssDNA probe with FAM capping headgroup and thiol end group washybridized with its complementary DNA sequence prior to incubation on the Au gate electrode of the FET, followed by a step of de-hybridization to obtainssDNA layer. b) SEM images illustrating different stages of the functionalization process. In Step 1, capsule-like structures of dsDNA can be observed.In Step 2, capsules are broken and a porous structure with layers is found in Step 3. Images with a red star in the corner are obtained after platinumcoating of the samples.leading to increased error-rates and read-out times of the targetdata unit. Indeed, the accessibility of the probe to the targetmolecule is restricted by the physical constraints imposed bythe substrate. To eliminate this partial hybridization issue, theintroduction of a bulky molecule such as fluorescein amidite(FAM) as a capping headgroup is proposed. Our hypothesis wasfirst tested in solution, where accessibility to the binding siteof the probe is ideal. Fluorescence emission by the fluoresceinheadgroup is quenched only when hybridization occurs withthe exactly complementary ssDNA (see Figure S3a, SupportingInformation). Perfect selectivity can be therefore attained byappending the FAM headgroup to the ssDNA target to suppresspartial hybridization involving complementary nucleotides.However, high concentrations, extended time periods and highpurity reagents are required to avoid interference when makingobservations by using fluorescence spectroscopy.To avoid these limitations, a new functionalization method isproposed here (Figure 3a) (called Nanopore-DNA-F method). TheFET Au gate electrode is first functionalized with dsDNA probesappended with the FAM headgroup by thiol-Au grafting reaction.The complementary DNA sequence is then removed by heatingthe active layer in de-ionized water to obtain the ssDNA function-alized DNA-FET. ssDNA probes used in this study are reported inTable S1 (Supporting Information). This strategy is assumed toimprove binding configuration by pre-orienting the ssDNA probeby positioning it at distance more favorable for strong multivalentbinding effect than would be free ssDNA probe.[41,42] It should benoted that FAM was chosen here for its pH sensitivity rather thanits fluorescence and it is also believed inhibit partial hybridizationbased on steric hindrance. FAM can also aggregate by protona-tion of its acid carboxyl group at pH around 7[43] (see Figure S3b,Supporting Information). SEM images (Figure 3b) show the vari-ations in structure observed during the functionalization process.Capsule-like structures of around 200 nm height present initiallyare broken by heating leading to a nanoporous structure andlayers. Nanoporous structures are unique to this functionaliza-tion method as showed in the comparative study (see Figure S4,Supporting Information) and confirmed by optical microscopyobservations (see Figure S5, Supporting Information). Further-more, ssDNA particle size and nanopore dimension appear tobe dependent on the ssDNA probe lengths (see Figure S6, Sup-porting Information). For ssDNA probe with 23 nt, nanoporesare measured to be 28 nm +/-5 nm (see Figure S7, SupportingInformation). The combination of the FAM capping moleculewith the prehybridization step in the Nanopore-DNA-F leads to ananoporous ssDNA structure at the gate electrode. It is importantAdv. Sensor Res. 2024, 3, 2300176 2300176 (5 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.comwww.advancedsciencenews.com www.advsensorres.comto emphasize that the functionalization of the gate electrode doesnot notably reduce the channel conductivity in the FET due to thepartial coverage of the gate surface (see Figure S2d, SupportingInformation).3.2. Selectivity of The ssDNA Active LayerID = W2L𝜇CTOT(VG − Vth)2(2)Equation 2 defines operation of the FET in the saturationregime,[44] where ID is the current in the channel of the semicon-ducting layer, W2Lis the dimension of the channel area, 𝜇 is theconductivity of the semiconducting layer, CTOT is the sum of theoverall capacitance of the device (channel capacitance/insulatinglayer, insulating layer/electrolyte, gate electrode/electrolyte), VGis the applied gate voltage, and Vth is the threshold voltage. Thevalue of Vth in the saturation regime can be correlated with oc-currence of the hybridization event involving the target ssDNAnear the gate surface. Pairing of the ssDNA leads to chemical dop-ing of the selective layer on the gate electrode, affects its electro-chemical potential (ΔEG), and modulates the work function.[45,46]This in turn tunes the operating voltage range of the FET with-out perturbing the transport properties and stability of the chan-nel material. The coplanar gate electrode structure is thereforecrucial to achieve segregated sensing operations without pollut-ing the semiconducting layer to avoid interference which mightmodify the channel transport properties. Moreover, as a precau-tion, the maximum gate voltage was set at –0.6 V to avoid leakagecurrent (see Figure S2c, Supporting Information) and maintainspecific DNA conformation (higher electric fields can affect theDNA conformation[46]).Selectivity performance of the nanoporous ssDNA layer ob-tained by the Nanopore-DNA-F was evaluated by using Equa-tion 3S =(1 −Vth 1 − Vth 0Vth 2 − Vth 0)∗ 100 (3)where S is the selectivity ratio, Vth 0 is extrapolated from the back-ward ID/VG transfer curves with only PBS X-0,01, Vth 1 fromtransfer curves after incubation with competitive ssDNA poolwith at least one-nucleotide difference in DNA sequence, andVth 2 from the same pool containing spiked target ssDNA. Thecloser the selectivity ratio S is to 100%, the better the discrimi-nation of the target ssDNA from the background is. In contrast,if S approaches 0%, differentiation of the target ssDNA from thebackground is difficult.Comparison of the selectivity ratio between ssDNA layer ob-tained by the Nanopore-DNA-F and the conventional method (noFAM, no pre-hybridization step) was made (Figure 4). Comparedto the conventional method, the results indicate almost perfectdiscrimination when complementary pairing occurs with the tar-get ssDNA with the newly designed ssDNA layer, even in thecompetitive ssDNA pool containing one-nucleotide different se-quence. Control measurements were undertaken to validate theselectivity ratio determination method (see Figure S8, Support-ing Information). To illustrate the importance of the FAM head-group and pre-hybridization step in the nanostructural organiza-tion of the selective ssDNA, S was measured in the absence of theFAM headgroup and without pre-hybridization step (Figure 5).The nanoporous structure is obtained only when FAM head-group is present and the prehybridization step is performed. Inthe absence of FAM, only non-porous aggregates were obtained.S is higher than 50% only when the nanoporous structure ispresent, suggesting increased accessibility of the target ssDNA tothe binding site on the substrate, possibly induced by the nanos-tructured form.The observed high selectivity of the ssDNA active layer wascross-checked by using surface plasmon resonance (SPR) mea-surements and compared with ssDNA layer obtained without thestep of pre-hybridization (B), without the FAM capping group onthe ssDNA probe (C), and with the standard functionalizationmethod (D) (no FAM and no pre-hybridization) (see Figure S9,Supporting Information). Saturation of the probes occurs after 30minutes. Without FAM capping-molecule and pre-hybridizationstep of the probes (layer B, C, & D), reflectivity evolves similarlyregardless of whether the target DNA is spiked in the competitiveDNA pool or not. Discrimination is therefore not possible, as ob-served by transistor measurements. For the ssDNA active layerobtained by using the newly designed functionalization method,competitive ssDNA does not interact at all with the absence of ki-netic evolution. A strong discrimination characteristic of ssDNAselective layer is therefore confirmed by transistor measurementsand qualitative analysis by SPR measurements.3.3. Performance and Limitations of DNA-FET for Random DataAccessThe performance of the DNA-FET for data access applications in-volving different ssDNA selective layer configurations and condi-tions was evaluated by comparing the calculated selectivity ratioS (Equation 3) for the retrieval of target short ssDNA in a com-petitive pool. The results (Figure 6a and see Figure S10a,b,c andTable S2, Supporting Information for the corresponding ID/VGtransfer curves and ssDNA sequences) indicate that it is possibleto achieve high discrimination with different ssDNA sequenceprobes in a highly concentrated pool containing nine competi-tive data units (with at least one data unit with one nucleotidedifference). Even when the target ssDNA concentration is low(10−16 M) (Figure 6b), detection and discrimination of the ss-DNA is observed in the competitive pool. The results thereforeshow the opportunity for high scalability (i.e., for ssDNA probesof 20 nt length, 420 (1 099 511 627 776) DNA sequence combi-nations are possible). The DNA-FET can also be recycled and re-used (Figure 6c) by simply heating the ssDNA modified gate elec-trode in DI water at 80°C, even if ID is decreased due to the or-ganic semiconducting layer alteration. In terms of ssDNA identi-fication time, our measurements (Figure 6d) show that it can bereduced to 9 min for one ssDNA read. It is also worth mention-ing that parallel ssDNA identification by DNA-FET is technicallyfeasible although it has not been demonstrated here.Despite the remarkable performance in terms of the promis-ing scalability of DNA-FET, there are also some limitations. In-creasing length of the ssDNA probes (35 and 45 nt) decreasesthe selectivity ratio S (Figure 7c), even if it is remains highcompared to the standard functionalization method. NanoporousAdv. Sensor Res. 2024, 3, 2300176 2300176 (6 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.comwww.advancedsciencenews.com www.advsensorres.comFigure 4. Selectivity of ssDNA layers obtained by the Nanopore-DNA-F method: comparison with the standard method. a) Schematic representationof the selectivity evaluation protocol by transistor measurements. An initial measurement in PBS X-0,01 (grey color) was used as a control reference.Subsequent 10 min incubation with the competitive ssDNA pool (10−5 M) containing at least one ssDNA sequence with one nucleotide difference wasperformed. After vigorous rinsing with deionized water, PBS X-0,01 was added and ID/VG measurement was performed (indicated by red). The same stepwas repeated with competitive ssDNA pool spiked with the target ssDNA (10−5 M) (indicated by blue lines). b) ID/VG transfer curves of the DNA-FETprepared using the Nanopore-DNA-F method (A) and the standard functionalization method (D) (no FAM and no pre-hybridization). The selective layersare illustrated with the corresponding SEM images. VD was fixed at –0.5 V. At least three measurement cycles were performed for each step. Grey tracescorrespond to absence of ssDNA (only PBS), red traces in the presence of competitive ssDNA, blue traces in the presence of competitive ssDNA spikedtogether with target DNA. c) Selectivity ratio S of the layer A and D calculated by using Equation 2 from the extrapolated threshold voltages Vth from thebackward ID/VG transfer curves at each step. Error bars are the SD of three measurement cycles. Triangles indicate the position of the extrapolated Vthfor each curve.dimensions, which depend on the ssDNA probes lengths (seeFigure S6, Supporting Information), also affect the selectivityratio. Another factor influencing the selectivity ratio is the sec-ondary structure folding temperature Tm of the ssDNA probes.Below the Tm, ssDNA forms secondary structures by homo-hybridization (i.e., donut structures). For ssDNA probes withTm closer to room temperature, reduced selectivity is observed(Figure 7b). Here we propose that Tm is a critical parameter in theformation of the nanoporous structure, which impacts the selec-tivity ratio. By fine-tuning the incubation temperature for eachssDNA probe, we believe that this limitation can be overcome.Additionally, further studies are required to explore the impact ofthe nucleotide sequence composition, which is directly correlatedto Tm, on the formation of nanoporous structures. Regarding thepersistence of the nanoporous structure, although this has notbeen fully investigated here, samples of the structure stored forone year exhibit similar binding efficiencies of ssDNA probes asthe freshly prepared devices.Integration of the DNA-FET in the current DNA storageprocess as direct random-access solution of the data stored inAdv. Sensor Res. 2024, 3, 2300176 2300176 (7 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.comwww.advancedsciencenews.com www.advsensorres.comFigure 5. Selectivity comparison of the Nanopore-DNA-F method when ssDNA probe is modified a) ID/VG backward transfer curves of the DNA-FETprepared using the Nanopore- DNA-F method (A), using the Nanopore-DNA-F method but without the prehybridization step (B), using the Nanopore-DNA-F method but without the FAM capping group on the ssDNA probe (C), using the conventional functionalization method (D) (no FAM and nopre-hybridization), and without the ssDNA selective layer (R). VD was fixed at −0.5 V. At least three measurement cycles were performed for eachstep. Grey traces correspond to absence of ssDNA (only PBS), red traces are in the presence of competitive ssDNA, blue traces are in the presenceof competitive ssDNA spiked together with target DNA. b) Selectivity ratio S of the layer A, B, C, D, and R calculated by using equation 2 from theextrapolated threshold voltages Vth obtained on the backward ID/VG transfer curves at each step. Error bars are the SD of three measurement cycles.Triangles indicate the position of the extrapolated Vth for each curve.dsDNA (by considering maximum length of 45 nt) has also beenconsidered. For this purpose, DNA-FET is required first to beprepared using dsDNA data units. Subsequent unpairing of ds-DNA by heating at 100°C is performed prior to transistor mea-surements. The results indicate reduced selectivity (Figure 7a)for this unoptimized process caused by rapid rehybridization ofthe ssDNA. Also, captured ssDNA data units need to be releasedfrom the surface and introduced to a sequencing device for inte-gration as a random-access tool in a data storage process. As theconcentration of released ssDNA is lower than the required min-imum concentration for sequencing, some technical adjustmentis required (i.e., increasing ssDNA probe density) prior to imple-mentation of this technique as direct random-access of DNA dataunit in the current data storage process.3.4. Proposed Sensing Mechanism of DNA-FETIn order to determine the limit of detection and sensitivity ofthe DNA-FET, the gate electrode coated with the ssDNA selec-tive layer was incubated with solutions containing different con-centrations of target ssDNA. A linear response of the DNA-FETwas obtained in the range 10−19 M – 10−11 M with a sensitivityof 10 mV dec−1 (Figure 8a,b). These low limits and wide rangescan be explained by two phenomena: first, transient electric fieldapplied by the gate electrode in the measurement environmentcan tilt the ssDNA probes, resulting in longer Debye lengths.[27,47]Furthermore, the use of dilute PBS enables lower ionic strengthand subsequently larger Debye length. Second, the very thin in-sulating electric double layer at the P3HT/electrolyte interfaceAdv. Sensor Res. 2024, 3, 2300176 2300176 (8 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.comwww.advancedsciencenews.com www.advsensorres.comFigure 6. Selectivity performance of the DNA-FET for ssDNA retrieval. a) Selectivity ratio S measured with two different ssDNA probe sequence of 23 ntin a pool composed of 9 different ssDNA sequences with at least one having one-nucleotide difference from the probe sequence. The concentration of thepool was fixed at 10 μM. b) Selectivity ratio S measured with the ssDNA probe sequence (T1) in a pool composed of nine different ssDNA sequences withat least one with one-nucleotide difference from the probe. The concentration of the pool background was fixed at 10 μM with a digressive concentrationof the target ssDNA sequence. c) Selectivity ratio S measured with two different ssDNA probes (T1 & T4) and four DNA-FET in a pool of nine competitivessDNA sequences after a step of device recycling based on heating the active layer in DI water at 80 °C for 2 h. d) Selectivity ratio S comparison withfaster measurement time. The measurement time for the sample T4f was decreased by removing the incubation steps and decreasing the ID/VG transfercurve recording time (from 4 min to 1 min for each cycle). Error bars correspond to the SD of three measurements.contributes to the high sensitivity as the capacitance is inverselyproportional to the thickness of the insulating layer. The com-bination of these phenomena might account for the attained ul-tralow detection limit. Decreases were also observed for ID andthe transconductance, gm (Figure 8c). Transconductance corre-sponds to the expression 𝜇CTOT,[48] the slope of the linear regionof the transfer curve. Values obtained on initial observation mightreasonably be assigned to a bias stress effect.[49] However, subse-quent observations indicate that is not the case. In fact, Vth didnot vary during repeated measurements at the same concentra-tion (by adding fresh solution), and only resulted in reductionsin ID and gm (see Figure S11a,b, Supporting Information.)To explain the sensing mechanism, we hypothesize that a de-crease in the value of the transconductance gm is associated onlywith a decrease of the capacitance of the gate electrode/electrolyteinterface Cs. In fact, capacitance drop at the ssDNA functional-ized gate electrode and electrolyte interface is observed in thepresence of target ssDNA (see Figure 11Sc, Supporting Informa-tion). It is unlikely that interference which might alter channeltransport properties will occur since we have performed segre-gated sensing operations without contaminating the semicon-ducting layer. Decrease of Cs occurs after grafting of the ssDNAprobe, hybridization of the ssDNA probe with the target ssDNA,and when the sensing area is overloaded by aggregated DNA.Adv. Sensor Res. 2024, 3, 2300176 2300176 (9 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.comwww.advancedsciencenews.com www.advsensorres.comFigure 7. Characteristics and performance limitations of the DNA-FET. a) Selectivity ratio S comparison for identification of ssDNA directly or ssDNAobtained after heating dsDNA solution at 100 °C for 20 min. Two different ssDNA probes were used (T1 & T4). b) Selectivity ratio S comparison withthe second structure folding temperature Tm for different ssDNA probes used in the experiments. c) Selectivity ratio S measured with three differentssDNA probe sequences of 23, 35, 45 nt length respectively in a pool composed of at least three different ssDNA sequences where at least one sequencehas a one-nucleotide difference from the probe. The concentration of the pool background was fixed at 10 μM. The error bars correspond to SD of threemeasurements.Figure 8. Detection range of the DNA-FET and transconductance evolution. a) Backward transfer curves of DNA-FET functionalized with the new methodand incubated for 10 minutes with solutions having increasing concentrations of target ssDNA, from 0 (10−23 M) to 10−7 M, and measured in PBS X-0,01after washing with DI water. Three cycles were performed before recording. VD was fixed at −0.5 V. b) Calibration curve of Vth obtained from the transfercurves normalized against the point at 0 [10−23 M]. Reported standard deviation are for N = 3 measurements. It was not possible to determine theVth for concentrations under 10−11 M because of the low ID. c) Transconductance gm obtained from the slope of transfer curves. Reported standarddeviation are for N = 3 measurements.Adv. Sensor Res. 2024, 3, 2300176 2300176 (10 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.comwww.advancedsciencenews.com www.advsensorres.comFigure 9. Transfer curves obtained at high and low off-state gate voltages. a) DNA-FET transfer curves with ssDNA functionalized by Nanopore-DNA-Fmethod (A) and modified Nanopore-DNA-F method (B, C, D, see Figure S4, Supporting Information) during PBS X-0,01 measurement cycles at a highoff-state gate voltage (when it starts at 0.6 V, full-line) and low off-state gate voltage (when it starts at 0.2 V, dashed-line). Five cycles were performed priorto data collection. Differences in the channel current 𝚫ID at VG = –0.6 V (turquoise color), transconductance 𝚫gm (purple colour) and 𝚫Vth (gold colour)for measurement cycles at high and low off-state gate voltages were extracted from the backward transfer curves. Vth shifts occurred in the directionof the applied gate voltage (negative side). b) Presented selective layers with competitive ssDNA solution (red) or competitive ssDNA solution spikedwith target ssDNA (blue) at high concentration (10−5 M) at a high off-state voltage (starting at 0.6 V, full-line) and low off-state voltage (starting at 0.2 V,dashed-line). No significant modification is observed between high and low off-state voltage measurements when the selective layer is saturated.Shift of the Vth is observed only when complete hybridization oc-curs. Aggregation of FAM molecules of the ssDNA probes shouldbe favored by the complete pairing of the nucleotide bases. Thisalso acts as a molecular gate and can lock the access of competi-tive ssDNA near the surface therefore preventing variation of theworking potential of the gate electrode.To confirm our hypothesis that the transconductance and thechannel current are correlated independently of the thresholdvoltage induced by the concentration changes in the captured tar-get ssDNA (Equation 2), transfer curves obtained by ssDNA se-lective layers A, B (with FAM) and C, D (without FAM) incubatedin DNA-free solution (only PBS X-0,01), competitive ssDNA so-lution or competitive ssDNA solution spiked with target ssDNAat high concentration (10−5 M) were compared with transistormeasurement cycles starting at 0.6 V (called high off-state gatevoltage) and ending at −0.6 V or starting at 0.2 V (called lowAdv. Sensor Res. 2024, 3, 2300176 2300176 (11 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.comwww.advancedsciencenews.com www.advsensorres.comFigure 10. Proposed discriminatory sensing mechanism. Scheme of the proposed sensing mechanism showing the DNA-FET sensing area on the gateelectrode at VG= −0.6 V comprising the ssDNA probes and the transducing area composed of P3HT semiconducting channel at different steps: ssDNAfunctionalization, hybridization and over-saturation. Relative changes in the capacitance at the gate electrode/electrolyte and the threshold voltage areindicated below each scheme. ID/VG transfer curves of each step are indicated next to each scheme.off-state gate voltage) and ending at −0.6 V. At higher off-statevoltage, when binding sites are vacant (i.e., in neat PBS X-0,01),the selective layers containing ssDNA layer with FAM (A, B) areexpected to condense near the surface since the FAM moieties arenegatively charged at pH 7.4 (i.e., pH +/- 0.2 of the PBS), leadingto higher charge density due to ion trapping than at lower off-statevoltage (Figure 9a). Transfer curves confirm that a high value ofΔID (difference of ID at VG = −0.6 V for measurement cycles athigh and low off-state gate voltage) is observed for the vacant se-lective layers A, B compared to layers C, D. A similar trend is ob-served for the transconductance. For Vth, a constant shift in thenegative side (direction of the applied gate voltage) is observedfor all the vacant selective layers, which is typically observed inthe case of bias-stress effects.[49] In contrast, when the surfaceis overloaded with ssDNA (complementary or not) (Figure 9b),ΔID and Δgm are almost unmodified regardless of the off-statevoltage, suggesting that DNA surface aggregation impedes DNAconformational changes in the vicinity of the surface. These re-sults highlight that a decrease in ID is induced by a decrease inthe capacitance of the gate electrode/electrolyte interface Cs.We can therefore confirm our initial hypothesis concerningthe sensing mechanism: any unreacted molecules or parasiticreactions are associated with a decrease in capacitance causedby screening of the gate electrode and the consequent weak-ening of the applied electrical field.[50,51] However, when hy-bridization occurs near the surface, strong H-bonds formed bypaired nucleotides result in modification of the work functionof the gate electrode leading to modulation of Vth[52] (Figure 10).This effect is further enhanced by the aggregation of adjacentFAM molecules in the selective layer[53] which can arise onlywhen complete DNA pairing is achieved. In fact, when the FAMmolecules are linked on the phosphate backbone of the ssDNAprobe and are sufficiently mutually remote, they can rotate in-dependently of any constraint imposed by the nucleotides.[43,54]Once aggregated, however, they can operate as a molecular gatepreventing competitive ssDNA access to areas close to the gateelectrode and preventing variations in gate electrode work func-tion.4. ConclusionIn this work, we demonstrate direct random access of shortssDNA sequence (23, 35 and 45 nt) in a highly concentrated(10−5 M) competitive pool (nine unique ssDNA sequence withat least one with one-nucleotide difference) by using an easy-to-prepare DNA-FET structure operating in the millivolt range.Fluorescein amidite FAM has been used effectively as a cappingmolecule to prevent partial ssDNA hybridization. By applyinglower and higher gate voltages in the off state during transistormeasurements, we are able to elucidate the mechanism respon-sible for the high degree of discrimination. It is also apparentfrom the measurements that nanostructuring of the active layerincluding well-defined nanopores which promote selectivity, iscritical for the device operation to achieve near error-free identi-fication of the DNA pool signature component. It can be operatedin a low target ssDNA concentration regime (10−16 M) in a con-centrated competitive pool (10−5 M), reducing the quantities ofDNA material required for operation, thus extending the lifetimeof random-access operation. Nevertheless, to obtain functionalityas an efficient RAM in the DNA data storage process, further crit-ical modifications are imperative. DNA-FETs present advantagesin terms of potential scalability. Through the use of the Nanopore-DNA-F method to functionalize multiple combined CMOS-basedtransistors with various ssDNA probes to simulate parallel oper-ation, a near error-free, fast-operating, reusable, and robust de-vice can be achieved. Subsequently, with the implementation ofAdv. Sensor Res. 2024, 3, 2300176 2300176 (12 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.comwww.advancedsciencenews.com www.advsensorres.comcapsule-like structures to contain substantial data quantities withshort unique ssDNA identifier, we are confident that our ultra-selective and sensitive DNA-FET can serve as a viable technologyfor retrieving DNA data units stored in an archive or active pool.Supporting InformationSupporting Information is available from the Wiley Online Library or fromthe author.AcknowledgementsThis work was supported by funding from Postdoctoral Fellowship of JapanSociety for the Promotion of Science program (JSPS P21747). This workwas partly supported by World Premier International Research Center Ini-tiative (WPI Initiative), MEXT, Japan. The authors are grateful to the JST-ERATO Yamauchi Materials Space Tectonics Project (JPMJER2003). Thiswork used the Queensland node of the NCRIS-enabled Australian NationalFabrication Facility (ANFF).Conflict of InterestThe authors declare no conflict of interest.Data Availability StatementThe data that support the findings of this study are available from the cor-responding author upon reasonable request.KeywordsDNA data storage, DNA field-effect transistors, nanoporous DNA layer,random-access memoryReceived: November 14, 2023Revised: January 8, 2024Published online: February 2, 2024[1] M. Gu, X. Li, Y. Cao, Light Sci. Appl. 2014, 3, 2.[2] M. Hilbert, P. López, Science 2011, 332, 60.[3] L. Organick, Y. J. Chen, S. Dumas Ang, R. Lopez, X. Liu, K. Strauss, L.Ceze, Nat. Commun. 2020, 11, 616.[4] R. N. Grass, R. Heckel, M. Puddu, D. Paunescu, W. J. Stark, Angew.Chem. – Int. Ed. 2015, 54, 2552.[5] N. Goldman, P. Bertone, S. Chen, C. Dessimoz, E. M. Leproust, B.Sipos, E. 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Technol. 2018, 7, 3032.[52] S. E. Doris, A. Pierre, R. A. Street, Adv. Mater. 2018, 30, 1706757.[53] M. Inouye, R. Ikeda, M. Takase, T. Tsuri, J. Chiba, Proc. Natl. Acad. Sci.USA 2005, 102, 11606.[54] B. Y. Michel, D. Dziuba, R. Benhida, A. P. Demchenko, A. Burger,Front. Chem. 2020, 8, 12.Adv. Sensor Res. 2024, 3, 2300176 2300176 (14 of 14) © 2024 The Authors. Advanced Sensor Research published by Wiley-VCH GmbH 27511219, 2024, 5, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adsr.202300176 by National Institute For, Wiley Online Library on [17/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advsensorres.com Nanoporous Dna Field Effect Transistor with Potential for Random-Access Memory Applications: A Selectivity Performance Evaluation 1. Introduction 2. Experimental Section 2.1. Materials 2.2. Semiconducting Layer Formation 2.3. ssDNA Selective Layer Formation 2.4. Detection Measurements 2.5. Imaging 2.5.1. SEM Imaging 2.5.2. AFM Imaging 2.6. Capacitance Measurements 2.7. SPR Measurements 3. Results and Discussion 3.1. Design of the DNA-FET 3.2. Selectivity of The ssDNA Active Layer 3.3. Performance and Limitations of DNA-FET for Random Data Access 3.4. Proposed Sensing Mechanism of DNA-FET 4. Conclusion Supporting Information Acknowledgements Conflict of Interest Data Availability Statement Keywords