Multisegment nanowire/nanoparticle hybrid arrays as electrochemical biosensors for simultaneous detection of antibiotics.

Antibiotics such as penicillin and tetracycline drugs are widely used in food animals to treat, control, and prevent diseases, and penicillin is approved for use to improve growth rates in pigs and poultry. However, due to the overuse of antibiotics in food and medical industry, the antimicrobial resistance is starting to show up in some developing countries. The antibiotic abuse may cause allergic reactions, resistance in microorganisms and general lowering of immunity in consumers of meat and dairy products. It is important and necessary to develop an easy, inexpensive, and quantitative sensing method to monitor and analyze the antibiotics concentration in real samples such as milk or meat. In this research, an electrochemical biosensor based on hybrid nanowire/nanoparticle array with various bio-molecular receptors was fabricated for the simultaneous detection of penicillin and tetracycline. The vertically aligned Pt-Au nanowire array has been prepared by an electrodeposition method within anodic aluminum oxide (AAO) membranes; L-cysteine was used to form a monolayer on the Au segment as the bio-receptor for tetracycline detection; electroless plating of Au nanoparticles was applied on the Pt nanowire segments, and then the penicillinase was immobilized on the Au nanoparticles using EDC/NHS cross-linker. The prepared Au(L-cysteine)-Pt(penicillinase) nanowire array electrode showed simultaneous detection ability and remarkably high sensitivity of penicillin and tetracycline, which are 41.2 μA μM-1 cm-2 for penicillin detection and 26.4 μA μM-1 cm-2 for tetracycline detection. The sensitivities of each analytes with different segment length were also investigated. Real sample tests with chicken and beef extract were conducted, which showed good recovery performance. Due to the advantages of the hybrid nanowire/nanoparticle array structure, this new sensor can serve as an enhanced platform for simultaneous detection of various bioanalytes.