DEVELOPMENT OF A COST EFFECTIVE ELECTRICAL CONDUCTIVITY METER FOR MICROLITER SCALE VOLUMES

摘要

Electrical characterization of new biomaterials is becoming increasingly important because of their promising usefulness in various applications, e.g. flexible electronics, implants, and stimulators. Unfortunately, traditional techniques are often incompatible with small scale development of new biomaterials. One of the most promising biomaterials currently being developed, due to its almost limitless uses and ability to be modified and manipulated, is major ampullate spider silk. Previous efforts to mimic the spider's spinning process have yielded a microfluidic device that can be used to composite a silk solution with a variety of materials to endow the fiber with new biological, chemical, and electrical functions. Sadly, development is hampered by a limited quantity of natural silk protein; thus, assessing new functions like electrical conductivity (EC) with current commercially available tools which require a minimum liquid volume of more than 5 ml for proper probe contact is often a logistic nightmare. Furthermore, EC meters generally necessitate an open container for probe access, a significant disadvantage for the volatile solvents necessary to resuspend natural silk. Thus, a first generation microfluidic device was designed to allow EC measurement of small liquid (< 1 ml) samples without having to manually insert probes. Modular components allow maintenance and expansion of the system, e.g. reaction to applied electric fields or EC measurement of biofilms. Future efforts will integrate the microfluidic EC meter into the previously developed fiber spinning device, allowing rapid in-line EC measurement and examination of EC changes during fiber formation. Ultimately, EC measurements will provide additional insight into fiber formation, allowing process enhancements.