| Biofluids (e.g. sweat, urine and wound exudate) play vital roles in numerous life-sustaining functions, including transporting nutrients and waste products, regulating body temperature, and serving as excretion media. Therefore, a facile method to manage and analyze various metrics of biofluid becomes important in various biomedical applications. However, the conventional methods have limitations including limited management capacity, requirement of external pumping source, cumbersome structure and discomfort for wear. In this dissertation, we have first introduced the novel interfacial microfluidic principles on superhydrophobic fabric substrate and demonstrated textile-based biofluidic management and analysis platforms. We started by developing a complete transport model of superhydrophobic-patterned interfacial microfluidics with theoretical simulation and experimental investigation, from which three new transport schemes have been discovered, including big-to-small droplet merging, droplet equalizing as well as bi-directional transporting. Utilizing the design principles of the fluidic transport process of interfacial microfluidics, a novel micropatterned superhydrophobic textile (MiST) platform was developed and fabricated using simple conventional stitching method. The MiST is completely composed of fabric materials (superhydrophobic cotton and hydrophilic yarns), and yet is able to achieve continuous surface tension-driven flow on the fabric surface for the first time. This new transport scheme on textile provides several new features which are beneficial for biofluid removal, including continuous and directional transport of biofluid without any external pumping sources, independently removal rate from evaporation, mostly dry and lightweight. In order to analysis the fluid transport at skin-fabric interface, we developed and characterized two transport modes: continuous and discrete modes for various interactions between the fabric and skin. In addition, the influence of gravitational force and the efficiency improvement of multi-inlet-one-outlet structure are discussed. As a proof-of-concept, the MiST was tested an artificial skin model and the fluid transport capacity of the platform has been demonstrated. Furthermore, with the capacity of collection and directional transport of biofluid over a large area of skin surface, we have designed a wearable real-time biofluid (perspiration) collection and measurement (BCM) system by utilizing a sweat collection pattern and a droplet formation structure. This novel measurement platform is able to convert the continuous flow of biofluid into a series of identical droplets, of which the formation duration is determined by the flow rate. This mechanism enables a continuous and facile real-time monitoring of the secretion rate over a controlled area of body without time or volume restrictions on the measurement. Both theoretical analysis and experimental results have been conducted to illustrate the optimization and functionality of the BCM system. As a demonstration, the BCM has been used to monitor the injection rate change of a programmed flow source and achieved good accuracy with fast response time. At last a headband has been fabricated and worn on human forehead to demonstrate the feasibility of sweat collection, removal and analysis integrated together in a wearable and flexible form. We believe these work present novel designs and results on the application of interfacial microfluidics which can be beneficial to address several key hurdles in the field of biofluidic management and analysis. |
