A kind of surface glycoprotein imprinting over magnetic Fe₃O₄@Au multifunctional nanofibers (NFs) was developed and investigated. Magnetic Fe₃O₄@Au nanoparticles (NPs) as the core materials were modified consecutively with aniline, 3-aminophenylboronic acid (APBA) and acrylic acid to introduce boronic acids and polymerizable double bonds. With horseradish peroxidase (HRP) as a glycoprotein template, thin protein-imprinted films were fabricated via radical induced graft copolymerization of monomers on the surface of the multifunctional NFs. Experimental results show that the magnetic multifunctional Fe₃O₄@Au NFs can not only direct the selective occurrence of imprinting polymerization, but also drive glycoprotein templates into the polymer through reversible covalent complex formation. The results show that the imprinted NFs reached saturated adsorption at 0.3 mg mL⁻¹ within 90 min and exhibited significant specific recognition towards the template protein. Moreover, the molecularly imprinted polymers (MIPs) were used to electrochemically detect HRP with good linearity in the range of low concentrations from 0.01 to 0.30 mg mL⁻¹ through molecular recognition of K₃[Fe(CN)₆] current response. The detection limit of this method was found to be 0.005 mg mL⁻¹ (S/N = 3). The synthetic strategy paves the way for preparation of functional nanomaterials by molecular imprinting technique and direct detection of proteins in a more convenient, simpler and cheaper way.

In this work, a portable electrochemical glucose sensor was studied based on a laser-induced graphene (LIG) composite electrode. A flexible graphene electrode was prepared using LIG technology. Poly(3,4-ethylene dioxythiophene) (PEDOT) and gold nanoparticles (Au NPs) were deposited on the electrode surface by potentiostatic deposition to obtain a composite electrode with good conductivity and stability. Glucose oxidase (GOx) was then immobilized using glutaraldehyde (GA) to create an LIG/PEDOT/Au/GOx micro-sensing interface. The concentration of glucose solution is directly related to the current value by chronoamperometry. Results show that the sensor based on the LIG/PEDOT/Au/GOx flexible electrode can detect glucose solutions within a concentration range of 0.5 × 10⁻⁵ to 2.5 × 10⁻³ mol L⁻¹. The modified LIG electrode provides the resulting glucose sensor with an excellent sensitivity of 341.67 μA mM⁻¹ cm⁻² and an ultra-low limit of detection (S/N = 3) of 0.2 × 10⁻⁵ mol L⁻¹. The prepared sensor exhibits high sensitivity, stability, and selectivity, making it suitable for analyzing biological fluid samples. The composite electrode is user-friendly, and can be built into a portable biosensor device through smartphone detection. Thus, the developed sensor has the potential to be applied in point-of-care platforms such as environmental monitoring, public health, and food safety.

A highly sensitive electrochemical immunoassay method for detection of H1N1 influenza virus with the signal amplification of CuO nanoparticles (NPs) has been demonstrated.