An ultrasensitive biosensing flexible chip using a novel silver@Prussian blue core-shell nanocube composite

A real-time, portable, ultrahigh sensitive and selective biosensing chip is desired to satisfy the urgent requirement of the practical application. In this study, a novel three-dimensional (3D) silver nanocubes@Prussian blue (AgNCs@PB) core-shell material has been designed to develop an ultrasensitive biosensing chip by a seed-mediated interfacial assembly approach. A Prussian blue (PB) shell with the 30.12 nm thickness was precisely controlled to in-situ grow on the whole surface of AgNCs through the electrostatic interaction. A flexible and portable biosensing chip was printed and functionalized by using this 3D AgNCs@PB biosensing material to integrate the superior conductivity from AgNCs and electrocatalytic activity from PB for the remarkable performance enhancement. This chip can realize about four times increase of the sensitivity compared with the other PB based screen-printing electrode (SPE), as well as a very wide linear response from 0.01 mM to 1.3 mM and an ultralow limit of detection (LOD) of 0.005 mM for the glucose detection with an excellent anti-interference ability. Especially, it also presented an ultra-accurate detection of the blood sugar in a real serum with a low deviation (3.37%).