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A simple microfluidic immunoassay card was developed based on polystyrene (PS) substrate for the detection of horse IgG, an inexpensive model analyte using fluorescence microscope. The primary antibody was captured onto the PS based on covalent bonding via a self-assembled monolayer (SAM) of thiol to pattern the surface chemistry on a gold-coated PS. The immunosensor chip layers were fabricated from sheets by CO(2) laser ablation. The functionalized PS surfaces after each step were characterized by contact angle measurement, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). After the antibody-antigen interaction as a sandwich immunoassay with a fluorescein isothiocyanate (FITC)-conjugated secondary antibody, the intensity of fluorescence was measured on-chip to determine the concentration of the target analyte. The present immunosensor chip showed a linear response range for horse IgG between 1 microg/ml and 80 microg/ml (r = 0.971, n = 3). The detection limit was found to be 0.71 microg/ml. The developed microfluidic system can be extended for various applications including medical diagnostics, microarray detection and observing protein-protein interactions.

This study investigates the performance of surface modification of polycaprolactone (PCL) membrane on the binding and release behavior of basic fibroblast growth factor (bFGF) for in vitro proliferation of porcine eosophageal smooth muscle cells (PESMCs). The PCL membrane surfaceswere treated using UV/ozone and the surface modified PCL was characterized using water contact angle measurement, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The immobilization of bFGFs on the treated and non-treated PCL surfaces was also investigated using atomic force microscopy (AFM). It was found that the growth factor uptake on the PCL membrane was increased about 2-fold after treatment, which was attributed to significant contribution of oxygen containing polar groups resulting from UV/ozone treatment. Compared to non-treated PCL the treated PCL showed a prolonged bFGF release indicated by a linear increase over the first 3 days followed by a moderate and slow release profile. Moreover, the proliferation assay of PESMCs revealed that bFGF released from treated PCL had significantly higher proliferation than that of untreated PCL film. Thus, the UV/ozone-treated PCL membranes immobilized with bFGF accelerate the proliferation of PESMCs and may play an important role in soft tissue engineering.