Preparation and application of triangular silver nanoplates/chitosan composite in surface plasmon resonance biosensing

This paper reports the utilization of triangular silver nanoplates (TSNPs) to enhance the sensitivity of surface plasmon resonance (SPR) biosensor. TSNPs modified with 3-mercaptopropinic acid (MPA) were simply mixed with chitosan and glutaraldehyde to form TSNPs/chitosan composite. The composite was deposited on Au film as immobilization substrate for SPR biosensor. The novel structures of TSNPs are preserved against etching by MPA and chitosan polymer. Moreover, chitosan cross-linked by glutaraldehyde enables antibody to be immobilized on fabricated substrate directly via Schiff alkali reaction. In the optimized conditions, the resulting biosensor based on TSNPs/chitosan composite shows a satisfactory response to bovine IgG in the concentration range of 0.075–40.00 μg mL−1. While the biosensor based on chitosan without TSNPs shows a response in the concentration range of 0.6–40 μg mL−1 and the biosensor based on Au film shows a response in the concentration range of 2.5–40 μg mL−1. The experiment results show that the sensitivity of SPR biosensor based on TSNPs/chitosan composite was significantly enhanced and the immobilization procedure of antibody was simplified.

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► Triangular silver nanoplates were prepared and used to amplify the SPR signal.
► Triangular silver nanoplates are preserved by MPA and chitosan polymer.
► The proposed substrate immobilizes antibodies directly without modification.
► The LOQ of present method for analyte is 32 times lower than that based on Au film.