Real-time and label-free biosensing with microfluidic-based split-ring-resonator sensor

In this work, a split ring resonator (SRR), the most important building block of metamaterial, is fabricated and integrated with a microfluidic chamber for biosensing. The SRR is patterned on a microwave printed circuit board while the microfluidic chamber is fabricated by casting of polydimethylsiloxane (PDMS). SRR was immobilized with Anti-Immunoglobulin G (IgG) for IgG detection by a standard covalent immobilization using Cystamine. The PDMS chamber was aligned and clamped on the circuit board and the electromagnetic response of the SRR sensor was continuously monitored when IgG analytes was flowed through the chamber. The reaction of Immunoglobulin G (IgG) and Anti-IgG results in a shift of resonance frequency. It was found that the response of the resonance frequency is sensitive to the IgG concentrations. Therefore, the SRR microfluidic scheme can be effectively used as an advanced bio-sensing device.