In Operando Observation of Neuropeptide Capture and Release on Graphene Field-Effect Transistor Biosensors with Picomolar Sensitivity

Abstract

Transmission electron microscopy (TEM) is being pushed to new capabilities which enable studies on systems that were previously out of reach. Among recent innovations, TEM through liquid cells (LC-TEM) enables in operando observation of biological phenomena. This work applies LC-TEM to the study of biological components as they interact on an abiotic surface. Specifically, analytes or target molecules like neuropeptide Y (NPY) are observed in operando on functional graphene field-effect transistor (GFET) biosensors. Biological recognition elements (BREs) identified using biopanning with affinity to NPY are used to functionalize graphene to obtain selectivity. On working devices capable of achieving picomolar responsivity to neuropeptide Y, LC-TEM reveals translational motion, stochastic positional fluctuations due to constrained Brownian motion, and rotational dynamics of captured analyte. Coupling these observations with the electrical responses of the GFET biosensors in response to analyte capture and/or release will potentially enable new insights leading to more advanced and capable biosensor designs.

PRADA: Portable Reusable Accurate Diagnostics with nanostar Antennas for multiplexed biomarker screening

“…A tri‐glycine spacer domain was inserted between the C‐terminal cysteine and the P2 peptide to extend the binding domain away from the gold surface. The NPY binding peptide, NP3 (‐FPNWSLRPMNQMGGGC‐), was also identified from a phage display peptide library 36 . The short peptides bind to different regions of antigens without competing with the target sites of antibodies on the capture probes.…”

“…The NPY binding peptide, NP3 (-FPNWSLRPMNQMGGGC-), was also identified from a phage display peptide library. 36 The short peptides bind to different regions of antigens without competing with the target sites of antibodies on the capture probes. These dodecapeptides have an average size of 2-3 nm obtained by molecular modeling calculations; this size is the molecular length of a linear, unconstrained, and extended dodecameric peptide.…”

Wearable electrochemical biosensors to measure biomarkers with complex blood-to-sweat partition such as proteins and hormones

“…10 ) (Table 1 ) [ 111 ]. Interestingly, the use of liquid cell transmission electron microscopy (LC-TEM) variation enabled researchers to study the interaction of the graphene chemisorbed PN1 and the NYP at the same time of measurements [ 112 ]. The last quoted platform was carried out in artificial sweat and was modeled using Gouy–Chapman–Stern representation for liquid-interface interaction.…”

Review of fabrication methods of large-area transparent graphene electrodes for industry

“…Potentially every single atom of the structure can be affected by an adsorbate, making graphene's inherent sensitivity high. Graphene based field-effect-transistor (GFET) sensor is a common and reliable sensor [204], and has been used recently e.g., for early detection of the Zika-virus [205], RNA and DNA detection down to 10 -17 mol/L concentrations [206,207], in operando TEM measurements of neuropeptide capture and release [208] as well as detection of SARS-CoV-2 virus [209], the cause of the global COVID-19 pandemic of 2020. Other measurement schemes can be used as well, such as, Hall effect in standard [210], gated [211] and photonic spin [212,213] Table 2 Summary of different graphene based transparent electrodes, where R s , T, DC / OP and R change refer to sheet resistance, transmittance (at nm unless otherwise specified), figure of merit and decrease of sheet resistance due to doping, respectively.…”