Enhanced bio-molecular interactions through recirculating microflows

A recirculating microfluidic platform has been developed for carrying out optical bio-detection. The present device can be used for passive mixing of the biological species with the microfluidic channel without immobilisation, through appropriate design and flow control. The feasibility of bio-detection using the present setup has been demonstrated through the method of fluorescence and the experiments were carried out with Antisheep Antibody (AB) tagged with Alexafluor 647 (AF647) fluorophore particles. By controlling the fluid flow, it was possible to isolate AB separately into a recirculation zone within the microfluidic channel, thereby enabling qualitative and quantitative bio-detection. Finite element modelling of the flow behaviour has been carried out and the results were similar to the results of flow visualisation obtained with tagged antibody particles. The present work thus provides confidence in using the hybrid integrated device for in situ rapid biomedical detection of biological pairs or individual specimen in fluorescence-based chemical and biological sensing.