A Novel Microfluidic Device That Passively Generates Chemical Gradients and Detects Oxygen Concentrations Under Bacterial Biofilms

This paper describes the use of micro-patterned stamps to create biofilm dot arrays for use in a microfluidic device. Staphylococcus aureus was grown on an agar plate and transferred to a glass slide coated with a platinum-porphyrin based oxygen sensing film via a PDMS stamp. After incubation, the resulting biofilms are robust and can be patterned to any shape and size ranging from 500µm to several mm. The technique is simple, reproducible and allows the biofilms to be observed without the need to fix the bacteria for observation. The oxygen film is able to detect aerobic metabolism in the biofilms quickly and easily, although the accuracy of the data is dependent on the maturity of the biofilms. Used in conjunction with a microfluidic device capable of generating a concentration gradient, this method allows for the real-time monitoring of biofilm structure and oxygen usage against a gradient of nutrients, toxins or antibiotics.