Label-Free Immunodetection in High Ionic Strength Solutions Using Carbon Nanotube Transistors with Nanobody Receptors

Filipiak, Marcin S.; Rother, Marcel; Andoy, Nesha May; Knudsen, Arne C.; Grimm, Stefan; Bachran, Christopher; Swee, Lee Kim; Zaumseil, Jana; Tarasov, Alexey

doi:10.3390/proceedings1040491

Cited by 4 publications

(4 citation statements)

References 14 publications

(17 reference statements)

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“…It is difficult to detect analyte-binding that are beyond the Debye length in the physiological environment. There have been attempts to address this problem by using short antibody fragments (e.g., nanobody receptor) or aptamer ( Figure 9 B), which enable the analyte to bind closer to the sensor surface and achieve a detection limit down to the sub-picomolar range without the loss of selectivity [ 116 ].…”

Section: Latest Developed Biosensors For Covid-19mentioning

confidence: 99%

Emerging Biosensors to Detect Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): A Review

2021

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Coronavirus disease (COVID-19) is a global health crisis caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) is the gold standard test for diagnosing COVID-19. Although it is highly accurate, this lab test requires highly-trained personnel and the turn-around time is long. Rapid and inexpensive immuno-diagnostic tests (antigen or antibody test) are available, but these point of care (POC) tests are not as accurate as the RT-PCR test. Biosensors are promising alternatives to these rapid POC tests. Here we review three types of recently developed biosensors for SARS-CoV-2 detection: surface plasmon resonance (SPR)-based, electrochemical and field-effect transistor (FET)-based biosensors. We explain the sensing principles and discuss the advantages and limitations of these sensors. The accuracies of these sensors need to be improved before they could be translated into POC devices for commercial use. We suggest potential biorecognition elements with highly selective target-analyte binding that could be explored to increase the true negative detection rate. To increase the true positive detection rate, we suggest two-dimensional materials and nanomaterials that could be used to modify the sensor surface to increase the sensitivity of the sensor.

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Section: Latest Developed Biosensors For Covid-19mentioning

confidence: 99%

Emerging Biosensors to Detect Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): A Review

2021

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“…Though this device does not rely on fluorescence for measurements, fluorescently labeled antibodies (with Alexa Fluor 647) are used due to the charge brought by the sulfonated fluorophore, which amplifies the measurable electrical charge signal upon binding. While there is certainly an appeal for label-free biosensing techniques − (one of the major advantages of electronic biosensing is that it typically avoids the need for labeling), this assay format makes use of the potential benefits of labeling (e.g., signal amplification) without increasing testing complexity or the number of steps for the end-user, as the labeled detection antibodies are printed onto the D4-TFT chip in proximity to the transistor. It is worth noting that during the printing process, cAb is only printed on some devices within a chip (directly over the CNT thin-film channel), whereas other devices are left as negative controls without any printed cAb, allowing for a direct in situ comparison of the effects of antibody-analyte-antibody binding within the same chip.…”

Section: Results and Discussionmentioning

confidence: 99%

Addressing Signal Drift and Screening for Detection of Biomarkers with Carbon Nanotube Transistors

Albarghouthi,

Semeniak,

Khanani

et al. 2024

ACS Nano

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Electrical biosensors, including transistor-based devices (i.e., BioFETs), have the potential to offer versatile biomarker detection in a simple, low-cost, scalable, and point-of-care manner. Semiconducting carbon nanotubes (CNTs) are among the most explored nanomaterial candidates for BioFETs due to their high electrical sensitivity and compatibility with diverse fabrication approaches. However, when operating in solutions at biologically relevant ionic strengths, CNT-based BioFETs suffer from debilitating levels of signal drift and charge screening, which are often unaccounted for or sidestepped (but not addressed) by testing in diluted solutions. In this work, we present an ultrasensitive CNT-based BioFET called the D4-TFT, an immunoassay with an electrical readout, which overcomes charge screening and drift-related limitations of BioFETs. In high ionic strength solution (1X PBS), the D4-TFT repeatedly and stably detects subfemtomolar biomarker concentrations in a point-of-care form factor by increasing the sensing distance in solution (Debye length) and mitigating signal drift effects. Debye length screening and biofouling effects are overcome using a poly(ethylene glycol)-like polymer brush interface (POEGMA) above the device into which antibodies are printed. Simultaneous testing of a control device having no antibodies printed over the CNT channel confirms successful detection of the target biomarker via an on-current shift caused by antibody sandwich formation. Drift in the target signal is mitigated by a combination of: (1) maximizing sensitivity by appropriate passivation alongside the polymer brush coating; (2) using a stable electrical testing configuration; and (3) enforcing a rigorous testing methodology that relies on infrequent DC sweeps rather than static or AC measurements. These improvements are realized in a relatively simple device using printed CNTs and antibodies for a low-cost, versatile platform for the ongoing pursuit of point-of-care BioFETs.

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“…Further application of the hysteresis technique in real time samples remains to be tested with a surface modification involving polyethylene glycol that allows increasing the effective Debye length [62][63][64]. The indication of certain diseases can also be further improved by using several bioreceptors and neural networks for fingerprinting of the samples [65,66].…”

Section: Discussionmentioning

confidence: 99%

Gating Hysteresis as an Indicator for Silicon Nanowire FET Biosensors

et al. 2018

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Abstract:We present a biosensor chip with integrated large area silicon nanowire-based field effect transistors (FET) for human α-thrombin detection and propose to implement the hysteresis width of the FET transfer curve as a reliable parameter to quantify the concentration of biomolecules in the solution. We further compare our results to conventional surface potential based measurements and demonstrate that both parameters distinctly respond at a different analyte concentration range. A combination of the two approaches would provide broader possibilities for detecting biomolecules that are present in a sample with highly variable concentrations, or distinct biomolecules that can be found at very different levels. Finally, we qualitatively discuss the physical and chemical origin of the hysteresis signal and associate it with the polarization of thrombin molecules upon binding to the receptor at the nanowire surface.

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Label-Free Immunodetection in High Ionic Strength Solutions Using Carbon Nanotube Transistors with Nanobody Receptors

Cited by 4 publications

References 14 publications

Emerging Biosensors to Detect Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): A Review

Emerging Biosensors to Detect Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): A Review

Addressing Signal Drift and Screening for Detection of Biomarkers with Carbon Nanotube Transistors

Gating Hysteresis as an Indicator for Silicon Nanowire FET Biosensors

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