Improved Sensitivity of AlGaN/GaN Field Effect Transistor Biosensors by Optimized Surface Functionalization

Wen, Xuejin; Schuette, Michael L.; Gupta, Samit Kumar; Nicholson, Theodore R.; Lee, S C; Lu, Wu

doi:10.1109/jsen.2010.2095458

Cited by 24 publications

(28 citation statements)

References 26 publications

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“…Consistent with theory [47], previous data [20,29,30,39,40,48] show that immuno-and bioFET signal magnitude is highly dependent on analyte charge to sensing channel proximity. Isrealachvili [47] states that FET signal magnitude varies with the sixth power of charge-to-surface distance.…”

Section: Resultssupporting

confidence: 81%

“…Results, though contrary to classical assessment [13,[15][16][17][18], are congruent with recent HFET protein-sensing results [20,21,24,25,29,30,40]. Nonetheless, the notion that some immunoHFETs are feasible in physiological environments is not widely accepted, motivating direct demonstration of the proposition here.…”

Section: Resultssupporting

confidence: 74%

“…The classical assessment is flawed in such a way that it can provide neither explanation nor rationale for limitations of immunoFETs, nor, more importantly, guide solutions to technical challenges for development of functioning immunoFETs. We provide proof for immunoHFETs operating in physiological solution, using an ion-impermeable platform (AlGaN/GaN HFETs) and show signal magnitude for a fixed analyte charge to be directly related to charge proximity to the sensing channel [20][21][22]29,30,39,40,44,48]. We believe recognition of the significance of these nuances to immunoFET function will facilitate development of a myriad of immunoFETs directed to other analytes working in high salt environments.…”

Section: Discussionmentioning

confidence: 99%

“…Some of the analyte charges should thus be expected to be held within the Debye length, and therefore analyte electrical fields should be detectable by FET. That antibody adsorption to surfaces is not typically oriented, and that antibodies are indeed highly flexible, is not only immunological orthodoxy but also provides a rationale for successful immuno-and bioFETs [20][21][22][23][24][25][26][27][28][29][30]. These facts also indicate that, when immunoFETs fail, the mechanism is probably not as described by the classical model.…”

Section: Introductionmentioning

confidence: 99%

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ImmunoFET feasibility in physiological salt environments

Casal

Wen

Gupta

et al. 2012

Phil. Trans. R. Soc. A.

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Field-effect transistors (FETs) are solid-state electrical devices featuring current sources, current drains and semiconductor channels through which charge carriers migrate. FETs can be inexpensive, detect analyte without label, exhibit exponential responses to surface potential changes mediated by analyte binding, require limited sample preparation and operate in real time. ImmunoFETs for protein sensing deploy bioaffinity elements on their channels (antibodies), analyte binding to which modulates immunoFET electrical properties. Historically, immunoFETs were assessed infeasible owing to ion shielding in physiological environments. We demonstrate reliable immunoFET sensing of chemokines by relatively ion-impermeable III-nitride immunoHFETs (heterojunction FETs) in physiological buffers. Data show that the specificity of detection follows the specificity of the antibodies used as receptors, allowing us to discriminate between individual highly related protein species (human and murine CXCL9) as well as mixed samples of analytes (native and biotinylated CXCL9). These capabilities demonstrate that immunoHFETs can be feasible, contrary to classical FET-sensing assessment. FET protein sensors may lead to point-of-care diagnostics that are faster and cheaper than immunoassay in clinical, biotechnological and environmental applications.

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Section: Resultssupporting

confidence: 81%

Section: Resultssupporting

confidence: 74%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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ImmunoFET feasibility in physiological salt environments

Casal

Wen

Gupta

et al. 2012

Phil. Trans. R. Soc. A.

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“…To enhance the device sensitivity, optimization of surface functionalization chemistry (12,13) and device configuration has been implemented. One effective strategy to optimize the device configuration is operating the devices in the subthreshold regime instead of the linear regime by applying a bias (V G ) to the reference electrode as a "control gate" (9,10).…”

Section: Introductionmentioning

confidence: 99%

(Invited) Planar Field Effect Transistor Biosensors: Toward Single Molecular Detection and Clinical Applications

Wang¹,

Sondergaard²,

Theiss³

et al. 2014

ECS Trans.

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In this research, a recessed gate AlGaN/GaN heterojunction field effect transistor (HFET) is demonstrated for biodetection sensitivity improvement. The measurements are performed on a zero-bias gate configuration to eliminate the noise and electrochemical activities from the gate electrode. A detection limit in terms of the concentration is demonstrated at 16 aM on a gate-recessed AlGaN/GaN bioHFET for streptavidin (SA) detection. The reduction of low frequency noise contributes to the signal to noise ratio (SNR) improvement. The recessed AlGaN/GaN bioHFETs have also been characterized in direct detection of biomarkers in physiological fluids at low concentrations for early-stage transplant rejection diagnostics. The electrical measurement results from recessed AlGaN/GaN bioHFETs are consistent with the patients' clinical behavior.

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Hybrid Organic–Nitride Semiconductor Nanostructures for Biosensor Applications

Bertani

2018

Functional Organic and Hybrid Nanostructured Materials

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Improved Sensitivity of AlGaN/GaN Field Effect Transistor Biosensors by Optimized Surface Functionalization

Cited by 24 publications

References 26 publications

ImmunoFET feasibility in physiological salt environments

ImmunoFET feasibility in physiological salt environments

(Invited) Planar Field Effect Transistor Biosensors: Toward Single Molecular Detection and Clinical Applications

Hybrid Organic–Nitride Semiconductor Nanostructures for Biosensor Applications

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