"Sensors: Biosensor Arrays from Intact Receptor Proteolipsomes Immobilized onto Surfaces"
The dominant receptor family involved in molecular sensing and signal transduction by the cell are the G protein-coupled membrane receptors (GPCRs) which are responsible for detecting extracellular molecular signals and transducing the signals via the coupled heterotrimeric G protein. GPCRs sense an expansive range of ligands, including neurotransmitters, odorant molecules and growth factors. The GPCR sensor molecular machinery is therefore a natural system to be used in the design of biosensors. The aim of this research grant is to develop biomimetic sensor arrays composed of GPCRs. The primary limitation with using GPCRs as a sensing element is that these receptors require a specialized lipid bilayer membrane environment to maintain activity ex vivo. Previous efforts in this direction have incorporated the GPCRs into planar bilayer structures on surfaces in order to fulfill the requirement of a lipid environment to maintain GPCR activity. The research approach of this grant is based on the immobilization of intact GPCR-liposomes (proteoliposomes) onto nanostructured surfaces with domains of controlled terminal functionality. These liposomes will contain the membrane protein receptors in the lipid bilayer and, more importantly, also encapsulate G proteins and their downstream targets such as phospholipase C, in the core of the liposome. This approach stands to significantly enhance the senstivity of GPCR arrays by harnesing the natural applification mechanisms of the cell due to the potential for encapsulation inside the proteoliposome. In principle, the design can be scaled-up using microfluidic concepts to explore the interactions in a multitude of combinations of ligand, receptor, G proteins and their downstream effectors.
The team consists of investigators with an established record of collaboration from the City College of New York, combining backgrounds in biophysics, bioengineering, interfacial engineering, biochemistry, chemical engineering, and genetics. It is the intention of this team to develop the science and required technology to achieve such a design and along the way provide a unique, multidisciplinary educational experience for the graduate, undergraduate, and post-graduate students that will be involved.
Furthermore, this provides a unique opportunity to interface graduate and undergraduate training efforts in surface science (NSF 9972892) and soft materials (NSF 0221589) already funded by the NSF with biochemistry training efforts funded by the NIH (RCMI, MARC, & RISE) that would otherwise function independently of one another. All the co-PIs are involved in one or more of the above mentioned efforts. These training efforts will provide additional resources such as undergraduate research funding and first-year graduate student funding. In addition, this proposal will take advantage of the recent successful efforts to secure infrastructure funding from the NSF and the DoD.
