Studies On Microfluidic Based Airborne Bacteria Enrichment And Rapid Detection System

Infectious diseases are always the key threats to human health and environmental security over the centuries. Many respiratory infectious diseases are caused by bacteria. Culture based gold standard methods for pathogen/resistance identification are labor intensive and time consuming resulting into delayed diagnosis of pathogens and increase in mortality and morbidity. Environment security is suffered more from microbe aerosol pollution. To solve the fundamental problem of rapid detection of infectious diseases, new technologies such as microfluidic chips were used to detect airborne bacteria existing in microbe aerosol accurately and rapidly with the help of enzyme-linked immune sorbent assay and loop-mediated isothermal amplification.This paper established a simple, cheap PDMS microfluidic device which is capable of fast and efficient airborne bacteria captures and enrichment. The device was validated with Escherichia coli(E. coli) and Mycobacterium smegmatis. The efficiency can reach close to100%in9minutes. The capture limit is lower than classic culture method. The staggered herringbone mixer (SHM) structure was the first time used in airborne bacteria enrichment on microfluidic chip. Based on this work, we developed a rapid detection method to detect airborne Mycobacterium tuberculosis bacteria with ELISA double sandwich method on microfluidic chip. This immumoassay system could successfully capture the antigen protein Ag85B of Mycobacterium tuberculosis. The microfluidic device is very convenient to operate, with fewer reagent consumption. The detection time is far less than the traditional ELISA reaction on96-well plates. This method has a very sensitivity and specificity. This method is better than one commercially available Kits during our experiment. After that, we present a device of microfluidic chip for airborne Escherichia coli bacteria capture and enrichment as well as rapid detection by another technology: Loop-mediated Isothermal Amplification. The enrichment and detection functions were realized the enrichment-LAMP functional integration on one microfluidic chip. This enrichment-detection system was feasible and showed a good specificity and a good sensitivity in Escherichia coli bacteria detection by LAMP method.10Escherichia coli bacteria could be detected as a positive result by this method, which is more sentive than ELISA and some of other detection methods.