Detection of Stress Hormone with Semiconducting Single-Walled Carbon Nanotube-Based Field-Effect Transistors

Abstract

Non-invasive detection and quantification of the stress hormone cortisol not only provides an assessment of stress level but also enables close monitoring of mental and physical health. Here, we report two types of field-effect transistors (FETs) based on semiconducting single-walled carbon nanotubes (sc-SWCNTs) as selective cortisol sensors. In one FET device configuration, cortisol antibody is directly attached to sc-SWCNTs. In the other, gold nanoparticles (Au NPs) are used as linkers between the antibody and the sc-SWCNTs to enhance the device conductance. We fabricated and characterized both device configurations to investigate how the nanomaterial interface to cortisol antibody influences the biosensor performance. We tested the sensors in artificial sweat and compared these two types of sensors in terms of limit of detection and sensitivity, and the results indicate that direct binding between antibody and sc-SWCNTs yields better biosensor characteristics.

An Ultrasensitive Norfentanyl Sensor Based on a Carbon Nanotube-Based Field-Effect Transistor for the Detection of Fentanyl Exposure

“…For devices adopting the direct coupling approach, the binding of norfentanyl on the device surface induced an increase in the conductance of the FET device, resulting in a corresponding increase in the relative response. This result is consistent with what we previously observed with cortisol antibody-functionalized sc-SWCNT FET biosensors for cortisol sensing utilizing the same approach . Similarly, the binding between norfentanyl and norfentanyl antibody likely relies on the nonpolar hydrogen−π interaction and cationic-π interaction between norfentanyl and amino acid residues inside the binding sites of the antibody such as aspartate (Asp) and tyrosine (Try) .…”

“…This result is consistent with what we previously observed with cortisol antibody-functionalized sc-SWCNT FET biosensors for cortisol sensing utilizing the same approach. 31 Similarly, the binding between norfentanyl and norfentanyl antibody likely relies on the nonpolar hydrogen−π interaction and cationic-π interaction between norfentanyl and amino acid residues inside the binding sites of the antibody such as aspartate (Asp) and tyrosine (Try). 42 Therefore, we attributed the sensor response to the redistribution of charges on the antibody upon norfentanyl binding, making the antibody less positively charged and consequently p-doping the sc-SWCNTs.…”

“…The AptG-FET platform with a coplanar Pt gate enabled multianalyte detection on a single chip and achieved a picogram per milliliter level limit of detection for noroxycodone (NX), 2-ethylidene-1,5- dimethyl-3,3-diphenylpyrrolidine (EDDP), and norfentanyl. Semiconductor-enriched (sc-) single-walled carbon nanotubes (SWCNTs), on the other hand, are particularly promising candidates for FET biosensors because the high-purity semiconducting content offers high on/off ratio for FETs, facilitating ultrasensitivity of sc-SWCNT-based FET biosensors. , Additionally, due to the presence of functional groups on the sidewalls, SWCNTs provide more avenues for functionalization with custom-designed chemistry to preferentially interact with target biomolecules, which leads to excellent sensitivity in complex media, such as saliva, sweat, and serum …”

“…Semiconductor-enriched (sc-) single-walled carbon nanotubes (SWCNTs), on the other hand, are particularly promising candidates for FET biosensors because the highpurity semiconducting content offers high on/off ratio for FETs, 27 facilitating ultrasensitivity of sc-SWCNT-based FET biosensors. 28,29 Additionally, due to the presence of functional groups on the sidewalls, SWCNTs provide more avenues for functionalization with custom-designed chemistry to preferentially interact with target biomolecules, which leads to excellent sensitivity in complex media, such as saliva, 30 sweat, 31 and serum. 32 This work aims to develop a functionalized carbon nanotube-based biosensor for ultrasensitive norfentanyl detection in body fluids and consequently make time-sensitive decisions.…”

Robust Biosensor Based on Carbon Nanotubes/Protein Hybrid Electrolyte Gated Transistors

“…This value is comparable to LOD reported for other cortisol FET and CNT-based biosensors. [41,42,57] As discussed above, the response recorded for the biosensor (S) is a sum of contributions due to specific and nonspecific interaction of cortisol with the antibodies functionalized gate electrode. Given that the non-specific contribution is smaller than the specific one and basically constant in the 10 pM-100 nM concentration range, it can be treated as an additive independent contribution that can be subtracted from the current response obtained with the functionalized gate.…”