The purpose of my research is to contribute towards improving the technology of lab-on-a-chip devices for biosensing applications. To this end, we employ synthetic mimics of the biological membrane called supported phospholipid bilayers (SLBs). These artificial membranes preserve key properties found in biological membranes such as the two-dimensional fluidity of the membrane components. As within real cells, this two-dimensional lateral rearrangement allows for the reorganization of membrane components such as proteins, which in turn facilitate protein-protein interactions in processes such as immune response, viral entry, cell signaling and other important biochemical events.
By incorporating these synthetic supported membranes within microfluidic devices we are able to study the biochemistry of the biomembrane and use this lab-on-a-chip system as a biosensor. However, a major problem is that the supported bilayers are fragile as they are destroyed when exposed to air and additionally, devices can be damaged or ‘fouled’ in the presence of other contaminants. This limits their applicability as biosensors outside of the laboratory environment.
Our strategy has been to incorporate lipopolymers within the supported membrane system. This approach is inspired by the complex architectures found in native membranes. By further mimicking this native polymeric structure, called the cell surface glycocalyx, we have been able to expand the characteristics of the synthetic membranes. In particular, we are able to design and create air-stable supported membranes that function after dehydration and are capable to withstand harsh environments. This opens many possibilities in their applications as ‘early-warning’ detectors that can be tailored to sense a variety of analytes such as viruses, bacteria, toxins and other chemical compounds. Furthermore, these polymeric membranes can perform multiple tasks ‘on chip’ such size selective discrimination of protein analytes. The ability to selectively discriminate among protein analytes in a simple microfluidic device eliminates complex or multiple procedures such as extraction and purification of the sample before analysis. This lab-on-a-chip method allows for the screening of complex mixtures or cellular extracts for applications that range from proteomics to clinical assays.