ENGS 86 Independent Projects (AB Students)


Cathy LiFollow

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Faculty Advisor

John X.J. Zhang

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Microfluidics and liquid biopsy on chip are growing in popularity as a method of detection and analysis used in point of care devices. The advantages of liquid biopsy include minimal invasiveness, low cost, shorter time from analysis to results, and less consumption of sample and reagents. Liquid biopsy has shown the ability to detect small concentrations of a biomarker of interest. However, some biomarkers, such as circulating tumor deoxyribose nucleic acid (DNA), exist in very small concentrations that make detection challenging. The integration of miniaturized polymerase chain reaction (PCR) with liquid biopsy techniques is a promising solution. Gold nanoparticles are used in some liquid biopsy techniques for sample capture and detection, and also function as light-to-heat converters that are useful in thermal cycling for PCR.

The capabilities of both lasers and light-emitting diodes (LEDs) to heat solutions of gold nanoparticles were tested. While the laser only led to minimal heating, the LED demonstrated promising results, achieving an 11°C temperature increase after 1 minute. LED-powered PCR is also more suitable for point of care applications, because of its low cost and ease-of-use. While there is significant research with regards to laser-powered heating, the research on LED-powered heating is significantly lacking in comparison. There is a need to further investigate and optimize LED-powered heating, with regards to nanoparticle shape and concentration, LED wavelength and voltage input, and thermal cycling temperatures.

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