Evaluation of Microvalves Developed for Point-of-Care Testing Devices Using Shape-Memory Polymers

Abstract

A temporal change in temperature in an actuating shape-memory polymer (SMP) valve has been measured by analyzing the fluorescence spectrum of sulforhodamine B in the aqueous solution. The SMP microvalve used in this study was recently developed by the authors. It is actuated by the shape recovery of poly(ε-caprolactone) (PCL), which is triggered by heat from a microheater. To obtain information about temperature rise during operation, we measured “temperature quenching” of the fluorescence from sulforhodamine B using laser-induced fluorescence (LIF) spectroscopy. The maximum temperature during valve actuation was approximately 60 °C and was slightly higher than the phase transition temperature 52 °C of the PCL material used in this study. The results indicate that the present microvalve is potentially applicable to practical point-of-care testing devices.