Microfluidics

It is desirable for medical diagnostic assays to have portable and low cost pumping schemes. Although capillary loading is the most common example, it cannot load dead-end channels, often have fibres that obstruct optics, and have surface treatment or geometrical constraints. On the other hand, conventional degas pumping lacks flow control, speed, and reliability. Here we report a new portable pumping system that does not require any peripheral equipment or external power sources/controls. Compared with conventional degas pumping, it has ~8 times less standard deviation in speed, is...

MicroRNAs can affect individual cells’ epigenetic modifications in a variety of biological processes such as cell cycle regulation, apoptosis, cell differentiation and maintenance of stemness. These modifications can be largely heterogeneous depending on the internal and external factors. However, traditional tube- based qPCR or microarray system is lack of sensitivity and requires intensive labor and time input. Current integrated single- cell miRNA detection platforms are lack of the capacity of handling thousands of cells at the same time for statistical meaningful data...

Microfluidic polymerase chain reaction (PCR) has been of great interest owing to its ability to perform rapid and specific nucleic acid amplification and analysis on small volumes of samples. One of the major drawbacks of microfluidic PCR is bubble generation and reagent evaporation, which can cause malfunctions. Here, we propose a bubble-free microfluidic PCR device via controlled fluid transfer. We design the PCR chamber surrounding circumferential chamber allows a guided-fluid transport of generated bubble to circumferential chamber through thin nanoporous PDMS sidewall. We...

This project aims to create single-layer microfluidic gain valves for use in microfluidic devices. Autonomous microfluidic devices are essential for the long-term development of versatile biological and chemical platforms; however, the challenges of creating effective control mechanisms – e.g., the need for variable pressure sources, signal degradation in cascaded devices, and multi-stage manufacture methods – have proven considerable. Using in situ optofluidic lithography, we develop a single-layer pressure-based valve system with a static gain greater than unity. We will...