Abstract
This work develops a highly sensitive immunoassay sensor for use in graphene oxide sheet (GOS)-based surface plasmon resonance (SPR) chips. This sensing film, which is formed by chemically modifying a GOS surface, has covalent bonds that strongly interact with the bovine serum albumin (BSA), explaining why it has a higher sensitivity. This GOS film-based SPR chip has a BSA concentration detection limit that is 100 times higher than that of the conventional Au-film-based sensor. The affinity constants (KA) on the GOS film-based SPR chip and the conventional SPR chip for 100 μg/ml BSA are 80.82 × 106 M-1 and 15.67 × 106 M-1, respectively. Therefore, the affinity constant of the GOS film-based SPR chip is 5.2 times higher than that of the conventional chip. With respect to the protein-protein interaction, the SPR sensor capability to detect angle changes at a low concentration anti-BSA of 75.75 nM on the GOS film-based SPR chip and the conventional SPR chip is 36.1867 and 26.1759 mdeg, respectively. At a high concentration, anti-BSA of 378.78 nM on the GOS film-based SPR chip and the conventional SPR chip reveals two times increases in the SPR angle shift. Above results demonstrate that the GOS film is promising for highly sensitive clinical diagnostic applications.
Highlights
As a novel class of two-dimensional carbon nanostructures, graphene oxide sheets (GOSs) have received considerable attention in recent years in the fields of plasmonics [1-3] and surface plasmon resonance (SPR) biosensors [4-11], following both experimental and theoretical scientific discoveries
The results demonstrate that this Cys-modified Au surface excellently immobilized a GOS film in an SPR chip
In summary, a GOS film was developed for binding with proteins based on SPR analysis for the purpose of immunoassay sensing
Summary
As a novel class of two-dimensional carbon nanostructures, graphene oxide sheets (GOSs) have received considerable attention in recent years in the fields of plasmonics [1-3] and surface plasmon resonance (SPR) biosensors [4-11], following both experimental and theoretical scientific discoveries. GOSs have remarkable optical [12-19] and biosensing [20-28] properties and are expected to have a wide range of applications. A GOS has a high surface area and sp[2] within an sp[3] matrix that can confine π-electrons [12-14,29]. GOSs contain oxygen at their surfaces in the form of epoxy (−O), hydroxyl (−OH), carboxyl (−COOH), and ether functional groups on a carbon framework [30-35]. The direct bandgap behavior of a GOS can be controlled by modification by oxidation that generates photoluminescence (PL) [16-19] and makes available chemically functionalized GOS with biological applications.
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