Environmental samples are complex and it is unrealistic to aim for a "one size fits all" biosensor for the detection of environmental analytes. At the same time, a non-systematic approach to biosensor design, resulting in a suite of very diverse sensors with few common features, hinders the necessary conceptual and fundamental understanding of environmental processes and the design of sensors for new targets. Thus, a group of European researchers and PI Baeumner have been funded by the European Commission in 2010 (for 4 years) for the development of a battery of nanoarray biosensors for the measurement of a spectrum of chemical and biological parameters. Development and fundamental studies of novel biorecognition elements, investigation of reactivities and fluxes of target analytes provide the fundamental understanding needed for the design of sensors for new analytes in complex environmental samples. Specifically, focus is on the process of developing three complementary sensing platforms (optical, liposomal, whole cell) integrating a single family of sensing proteins as biorecognition element capable of sensing an unlimited number of pollutants. Bacterial periplasmic binding proteins (PBPs) are genetically engineered to bind specifically and sensitively to a wide range of analytes relevant to environmental analysis including heavy metals, pesticides and pathogens.
The following studies are proposed here in order to gain fundamental understanding of a liposome-based PBP sensing platform prior to its application via the EU project: (1) fundamental understanding of PBPs as biorecognition elements using surface plasmon resonance (SPR), including affinity and kinetic binding studies, (2) development of liposome-based PBP microtiter plate fluorescence assays gaining information on PBP as biorecognition element in effective bioassays in environmental matrices with a quantified characterization of the proteins, (3) development of electrochemiluminescence-based microfluidic liposome biosensors for sensitive environmental analysis avoiding matrix-related non-specific signals. This complements studies carried out with EU partners including (4) surface characterization of PBP-bound liposomes using atomic force microscopy (AFM) and determination of the PBP-analyte binding strength, (5) studies to determine the ability of liposomes to enhance Mach-Zehnder interferometer sensitivity, and (6) the investigation of liposomes as cell-mimics in hydrogels assisting in the study of bioavailability of inorganic and organic compounds.
The scientific merit of the specific studies proposed here is the gaining of fundamental knowledge about novel biorecognition approaches leveraging genetically engineered PBPs developed by EU partners. Also, highly sensitive and discriminative environmental biosensors will be developed through a liposome-based electrochemiluminescence (ECL) microfluidic strategy. In addition, via intensive interactions with the EU partners, liposomes will be investigated as multifunctional particles. The scientific merit of the overall studies by the EU partners and PI Baeumner is based on the multidisciplinary approach to developing a generic dynamic framework for quantitative interpretation of the "exposure to effect" chain of processes that determine the biological impacts of pollutants.
The broader impact includes (1) the construction and testing of a new generation of biosensors for environmental monitoring by commercial environmental monitoring agency partners within the EU team. This provides direct opportunities for commercialization and transfer of knowledge to relevant end users of the produced technology. Data will be provided directly to the EU and may help in the setting of environmental policies. (2) Organization of workshops for end-users, and intensive training courses for graduate students and postdocs. (3) In addition, PI Baeumner will ensure training of undergraduate students in biosensing research and continue her outreach to high school students with an Indian Tribal High Schools in the upstate NY area.
