Green Fabrication of (6,5)Carbon Nanotube/Protein Transistor Endowed with Specific Recognition

Abstract

will attenuate their invasiveness, yielding a reduced reaction of the living organism against a foreign object: the main visible effects are the enhancement of the signalto-noise ratio, and higher spatio-temporal resolution. The ultimate progress from bioelectronics to nano-bioelectronics [5,6] will exploit nanowires, low-dimensional materials, and nanostructured carbon allotropes such as carbon nanotubes (CNTs). These promising candidates for high performing transducers are characterized by outstanding electronic properties. [7][8][9][10][11][12][13][14][15][16][17] In particular, the interest for CNTs as biosensor components [18][19][20][21][22][23][24][25][26] is further supported by their exceptional electrical performances, even at small applied potentials (<1 V). CNT-field-effect transistor-based biosensors have shown great potential for ultrasensitive biomarker detection despite the presence of important challenges, which include difficulty in stable functionalization, incompatibility with scalable fabrication, and nonuniform performance. [27] A crucial challenge lies in the CNTs insolubility both in water and in organic solvents and in their high tendency to aggregate that hinder their wide applicability. Methods enabling their processability are strongly needed.A general single-step approach is introduced for the green fabrication of hybrid biosensors from water dispersion. The resulting device integrates the semiconducting properties of a carbon nanotube (CNT) and the functionality of a protein. In the initial aqueous phase, the protein (viz., lysozyme [LZ]) disperses the (6,5)CNT. Drop-casting of the dispersion on a test pattern (a silicon wafer with interdigitated Au source and drain electrodes) yields a fully operating, robust, electrolyte-gated transistor (EGT) in one step. The EGT response to biorecognition is then assessed using the LZ inhibitor N-acetyl glucosamine trisaccharide. Analysis of the output signal allows one to extract a protein-substrate binding constant in line with values reported for the free (without CNT) system. The methodology is robust, easy to optimize, redirectable toward different targets and sets the grounds for a new class of CNT-protein biosensors that overcome many limitations of the technology of fabrication of CNT biosensors.

Deciphering the Reactive Pathways of Competitive Reactions inside Carbon Nanotubes

“…When the tube is too narrow or too broad, the reactions are inhibited. In general, shape complementarity is a crucial factor for the interaction between carbon nanomaterials and molecules [ 57 , 58 , 59 , 60 , 61 , 62 ].…”

Reduced Graphene Oxide Electrolyte‐Gated Transistor Immunosensor with Highly Selective Multiparametric Detection of Anti‐Drug Antibodies

“…Electrolyte-Gated Transistors (EGTs) are ideally suited for POC immunosensing because of their rapid response, safe low-voltage operations, disposable items, and low-cost manufacturing. [10][11][12][13] Recently, we demonstrated the first label-free ADAs immunosensors with electrolyte-gated organic field-effect transistors (EGOFETs) where the drug (Nivolumab, a drug targeted to melanoma) was used as the specific biorecognition element in the device. The EGOFET exhibited high sensitivity (10 11 m −1 at 10 −12 m ADA) and theoretical limit of detection (LOD) in the fm range required for ADA.…”

Enhancing Electrochemical Transistors Based on Polymer-Wrapped (6,5) Carbon Nanotube Networks with Ethylene Glycol Side Chains

“…SWCNT networks are frequently applied in electrolyte-gated transistors with ionic liquids or ion gels − and as sensors in aqueous media. − While they are often assumed to be highly porous and more open than, e.g., a polymer film, not all of the nanotube surfaces are completely accessible in a thick film including bundles and not all nanotubes are completely surrounded by ions forming an electric double layer under bias. Furthermore, the alkyl side chains of most wrapping polymers do not provide ion-coordination sites and do not promote hydration or ionic diffusion with aqueous electrolytes.…”