Affinity analytical performance of GFC-LFIDs with enhanced signal and sensitivity. (a) Capture efficiency evaluated by the intensity of the detection line for different constriction widths and lengths. The images are the crop of the actual simultaneously scanned samples used in the evaluation. Error bars correspond to a 95% confidence interval for samples measured in triplicate. (b) GFC-LFID (0.5 mm, 7 mm, 60°, 45°) shows a ~10-fold increase in sensitivity compared with the conventional LFID for detection of IL-6, while using only 1/10 of the antibody benefit to the small laser configured test zone region.