We demonstrate a novel optofluidic micropipette device for filter-free fluorescence-based biosensing. The optofluidicmicropipette tube composed of a glass capillary microtube and a polymer-based structure designed to load analyte solutionusing a regular micropipette and serves as an optical waveguide. Ray-tracing simulations suggest that the excitation lightcan be effectively guided along the glass capillary with a small amount of leakage through the scattering at the solutionairinterface. Fluorescence emission of the analyte propagates in the radial direction of the glass capillary which can beefficiently captured by a smartphone camera through a miniaturized objective lens. Fluorescence intensity and spectrawere characterized using Rhodamine 6G (R6G) with various concentrations. The emission was collected via a microscopewith 5X magnification and a smartphone camera. Both experimental and simulation results suggest that the excitation raysare efficiently coupled into the glass micropipette tube for fluorescence excitation. The fluorescence emissions from theanalyte will either pass along the glass tube or propagate in the radial direction collected by the detector. A limited amountof excitation leakage scattered from the liquid-air interface showed a minimal effect on fluorescence detection. Wedemonstrated the platform that combines the optofluidic micropipette and smartphone camera to detect steroid hormone.
展开▼
