Electrochemical analysis is a promising method for biosensing. In our current work, a highly sensitive nanostructured electrochemical biosensor based on a 3D sensing element featuring uniformly deposited gold nanoparticles has been developed. A modified anodic aluminum oxide (AAO) barrier-layer surface is used as the template for nickel thin film deposition. After etching the AAO template off, a 3D mold of the concave nano structure array is created. The fabricated 3D nickel mold is further used for replica molding of a nano-structure polycarbonate (PC) substrate by hot embossing. An Au thin film is then sputtered on the PC substrate to form the electrode followed by the deposition of an orderly and uniform gold nanoparticles (GNPs) layer on the 3D Au electrode using electrochemical deposition. The detections of the dust mite antigen Der p2, allergy patient’s serum, allergy disease-related gene mutations (SNP and Haplotype), dengue virus-receptor binding, hepatitis B virus DNA, Alzheimer’s (AD) Aβ protein have been successfully carried out using electrochemical impedance spectroscopy (EIS) analysis.
In addition to the above nanostructured electrochemical biosensor, our group has also developed a cost effective and high sensitive non-enzymatic glucose biosensor based on a nano/micro hybrid-structured gold electrode. For this novel electrode, a uniformly distributed micro-hemisphere array of polycarbonate is fabricated by hot embossing using a nickel mold. The nano/micro hybrid-structured gold anode is then fabricated by depositing a gold nanoparticle monolayer on the micro-hemisphere array using 1,6-hexanedithiol (1,6-HDT) as the two-side anchor. Chronoamperometry (CA) detection of glucose demonstrated that the proposed non-enzymatic glucose biosensor can operate in a linear range from 1.39 to 13.89 mM with a sensitivity of 336.1 μA•mM−1•cm−2 and a detection limit of 5.2 µM. The accuracy of the developed glucose biosensor reaches ±1.29%, which is significantly better than the FDA and ISO 15197 standard of ±15%. The relatively high repeatability of the proposed glucose biosensor can be attributed to the uniform semiconductor fabrication process and the extremely ordered self-assembled monolayer of gold nanoparticles. The proposed biosensor can be easily produced on a large scale, the cost of fabrication is low, repeatability is high, and is easy to preserve on a long-term basis.
