Chitosan mediated layer-by-layer assembly based graphene oxide decorated surface plasmon resonance biosensor for highly sensitive detection of β-amyloid

Alzheimer's disease (AD), and its consequent effect primarily clinical dementia, Parkinson's disease dementia, etc. currently bring potential avenues for diagnosis centered on identification of beta-amyloid1-42 (A beta 1-42). Unfortunately, techniques engaged in AD core biomarker (A beta 1-42) detection are majorly suffering from poor sensitivity and selectivity. Thus, we fabricated graphene oxide (GO) surface decorated chitosan (CS) mediated layer-by-layer (LbL) assembly based surface plasmon resonance (SPR) biosensor for highly sensitive and selective recognition of A beta 1-42. Briefly, silver nanoparticles (AgNPs) and GO synthesis were achieved through a greener approach. LbL assembly was designed using CS and polystyrene sulphonate (PSS) on surface of AgNPs (AgNPsCS-PSS-CS) and then antibodies of A beta (anti-A beta) were fixed on LbL assembly (AgNPs-CS-PSS-CS@anti-A beta). Herein, amine functionality of CS offers a plethora of sites for anti-A beta antibody immobilization that gives specific direction, high selectivity, and an adequate amount of antibody immobilization. For fabrication, synthesized GO was immobilized on an amine-modified gold-coated sensor chip via carbodiimide chemistry followed by AgNPsCS-PSS-CS@anti-A beta immobilization on an activated GO surface. Inimitable features of LbL assembly showed improved selectivity towards A beta peptide whereas utilization of affinity biotransducer with a combination of plasmonic and non-plasmonic nanomaterial improved sensitivity and selectivity. Consequently, linearity range and limit of detection (LOD) of A beta 1-42 antigens were found to be 2 fg/mL to 400 ng/mL and 1.21 fg/mL, respectively. Moreover, analysis of A beta 1-42 in AD-induced rats confirmed the real-time-applicability of the designed SPR biosensor. Hence, GO surface decorated AgNPs-CS-PSS-CS@anti-A beta mediated SPR biosensor would provide a novel approach for exceptionally sensitive and selective A beta detection.

Automated summary

Alzheimer's disease (AD) and its associated clinical dementia present new possibilities for diagnosis. Unfortunately, current techniques for detecting AD core biomarkers suffer from poor sensitivity and selectivity. Therefore, researchers have developed a graphene oxide surface decorated chitosan mediated layer-by-layer assembly-based surface plasmon resonance biosensor for highly sensitive and selective recognition of A beta 1-42.