Selective Detection of Target Proteins by Peptide‐Enabled Graphene Biosensor

Abstract

Direct molecular detection of biomarkers is a promising approach for diagnosis and monitoring of numerous diseases, as well as a cornerstone of modern molecular medicine and drug discovery. Currently, clinical applications of biomarkers are limited by the sensitivity, complexity and low selectivity of available indirect detection methods. Electronic 1D and 2D nano-materials such as carbon nanotubes and graphene, respectively, offer unique advantages as sensing substrates for simple, fast and ultrasensitive detection of biomolecular binding. Versatile methods, however, have yet to be developed for simultaneous functionalization and passivation of the sensor surface to allow for enhanced detection and selectivity of the device. Herein, we demonstrate selective detection of a model protein against a background of serum protein using a graphene sensor functionalized via self-assembling multifunctional short peptides. The two peptides are engineered to bind to graphene and undergo co-assembly in the form of an ordered monomolecular film on the substrate. While the probe peptide displays the bioactive molecule, the passivating peptide prevents non-specific protein adsorption onto the device surface, ensuring target selectivity. In particular, we demonstrate a graphene field effect transistor (gFET) biosensor which can detect streptavidin against a background of serum bovine albumin at less than 50 ng/ml. Our nano-sensor design, allows us to restore the graphene surface and utilize each sensor in multiple experiments. The peptide-enabled gFET device has great potential to address a variety of bio-sensing problems, such as studying ligand-receptor interactions, or detection of biomarkers in a clinical setting.

Field-effect sensors – from pH sensing to biosensing: sensitivity enhancement using streptavidin–biotin as a model system

“…26,28,32,36,49,51,107,120,[160][161][162][163][164][165][166] The simplest model for biomolecule-binding reactions, is the first-order Langmuir model of surface-reactions (details in ESI section 10 †). In this model the surface reaction of analyte (A) to the surface sites (S) is treated simply:…”

Facile and controllable one-step fabrication of molecularly imprinted polymer membrane by magnetic field directed self-assembly for electrochemical sensing of glutathione

“…Graphene, a two-dimensional nanomaterial with one or several atomic layers of carbons, has become an ideal material for the preparation of sensors owing to its novel properties such as large specific surface area, exceptional thermal and mechanical properties, and high electrical conductivity [36][37][38]. Therefore, it could be a satisfactory alternative for preparing the ternary electromagnetic nanocomposites by the combination of Fe 3 O 4 , PANI and the reduced oxide graphene [39][40][41][42].…”

Hydrogen‐Terminated Si Nanowires as Label‐Free Colorimetric Sensors in the Ultrasensitive and Highly Selective Detection of Fluoride Anions in Pure Water Phase

“…[1][2][3][4][5] Colorimetric sensors developed using nanostructures such as Au nanoparticles (NPs) can transform detected events into color changes that can be conveniently perceived by the naked eye. Thus, nanostructures can be applied in fi eld analysis and point-of-care diagnosis.…”

“…Although colorimetric sensors have demonstrated more advantages in aqueous detection than traditional organic chemical sensors, the development of such sensors using nanostructures remains a challenge because their surfaces must be tailored to improve their dispersibility, selectivity, and stability. [ 5,[16][17][18][19][20][21][22][23][24][25] The most commonly used nanostructures, such as carbon nanotube and graphene oxide, have hydrophobic surfaces, which should therefore be modifi ed to improve their dispersibility in water. [ 16,17 ] Similarly, metal and semiconductor NPs require surface modifi cation to achieve practical stability.…”