Biological/biochemistry analyses traditionally require bulky instruments and a great amount of volume of biological/chemical agents, and many procedures have to be performed in certain locations such as medical centers or research institutions. These limitations usually include time delay in testing. The delays may be critical for some aspects such as disease prevention or patient treatment. One solution to this issue is the realization of point-of-care (POC) testings for patients, a domain in public health, meaning that health cares are provided near the sites of patients using well-designed and portable medical devices. Transportation of samples between local and central institutions can therefore be reduced, facilitating early and fast diagnosis. A closely related topic in engineering, lab-on-a-chip (LOC), has been discussed and practiced in recent years. LOC emphasizes integrating several functions of laboratory processes in a small portable device and performing analysis using only a very small amount of sample volume, to achieve low-cost and rapid analysis. From an engineer's point of view, LOC is the strategy to practice the idea of POC testing. This dissertation aimed at exploring the POC potentials of porous membrane-base LOC devices, which can be used to simplify traditional and standard laboratory procedures. In this study, three LOC prototypes are shown and discussed. First the protein sensor incorporating with silica nanofiber membrane, which has shown 32 times more improvement of sensitivity than a conventional technique and a much shorter detection time; secondly the bacteria filter chip that uses a sandwiched aluminum oxide membrane to stabilize the bacteria and monitor the efficacy of antibiotics, which has reduced the test time from 1 day of the traditional methods to 1 hour; the third is the sensor combining microfluidics and silica nanofiber membrane to realize Surface Enhanced Raman Spectroscopy on bio-molecules, which has enhancement factor 10^9 and detection limit down to nanomolar, but simple manufacturing procedures and reduced fabrication cost. These results show the porous-base membrane LOC devices may have potentials in improving and replacing traditional detection methods and eventually be used in POC applications.
