Measuring concentration fields in microfluidic channels in situ with a Fabry–Perot interferometer

摘要: Recent advancements in microfluidic technology have allowed for the generation and control of complex chemical gradients; however, few general techniques can measure these spatio-temporal concentration profiles without fluorescent labeling. Here we describe a Fabry–Perot interferometric technique, capable measuring situ, any label, by tracking Fringes Equal Chromatic Order (FECO). The technique has sensitivity 10−5 RIU, which be used to track local solute changes ~0.05% (w/w). is spatially resolved (1 μm) easily measures evolving fields with ~20 Hz rate. Here, demonstrate binary diffusion coefficients various solutes solvents (and their concentration-dependence) both free solution polyethylene glycol diacrylate (PEG-DA) hydrogels.