In this paper, we report the development of time-delay analysis method of inductance and capacitance for microfluidic circuit. The sensor used in this method is composed of the sensing inductor (SI) and the sensing capacitor (SC) with a microfluidic circuit. This sensor measures inductance and capacitance in a time difference by delaying with microfluidic circuit. We confirmed that SI and SC have different responses to conductive and dielectric solution. This research is expected to be applied to the combined analysis of liquid samples.

We developed a bi-channel microfluidic device integrated with a four-probe electrode system to measure the trans-epithelial electrical resistance (TEER). Time course of TEER was monitored when the extracellular Ca²⁺ was removed and replenished both from the upper and lower channels. We showed that tight junctions were disrupted rapidly once Ca²⁺ was removed from the basal side. However, when Ca²⁺ was removed from the apical side such disruption progressed slowly. Upon replenishing Ca²⁺ content at the basal side the TEER recovery pace was also faster than the case of replenishing it at the apical side. We conclude that cell polarity needs to be taken into account during the process of Ca²⁺ removal/replacement in explaining the dynamics of tight junction disruption/recovery. These results indicate that our approach can be utilized in detecting cell polarity in real time and low invasion.

In this study, the YAG:Ce³⁺ phosphor powder was used to fabricate polymer-based photonic crystal (PhC) for obtaining an enhancement of the fluorescence intensity. For fabricating PhC, YAG:Ce³⁺ phosphor powder was dispersed into the photocurable polymer, and then the PhC structure was transferred by using nanoimprint lithography. The optical characterization was carried out by monitoring the fluorescence intensity using a blue LED (460 nm) as a light source. For the evaluation of usability for sensor application, fluorescence intensity changes due to the adsorption of bovine serum albumin (BSA) were carried out. As the amount of BSA molecules adsorbed on the PhC surface increased, a decrease in fluorescence intensity depending on the BSA concentration was observed. Based on these results, the YAG:Ce³⁺ phosphor powder contained photonic crystal has the potential for biosensor application.