Liposomes are of great interest to the scientific community for their use to convey vaccines, drugs or other substances to target cells or organs. Conjugated polydiacetylene (PDA) liposomes have sensitive optical characteristics which make them excellent sensors for the detection of virus, DNA, toxins and biologically relevant molecules. We describe here, an approach for protein-bilayer interactions based on the changes in optical properties of the polydiacetylene (PDA) liposomes. These interactions occur following chemical reactions at the liposome surface which amplified the optical signal. We present our preliminary results on the design and optimization of modified PDA liposomes and their enhanced sensitivity towards multiple proteins. We demonstrate that covalent binding of proteins with liposomes yielded colorimetric responses that were dependent upon molecular weight of the proteins. Interestingly, we have used enzymatic cleavage rate to obtain information on the protein. For example, enzymatic cleavage of myosin bound to liposome showed a much larger response for papain as compared to trypsin. Finally, we will describe our results where colorimetric response provided a wealth of information on the protein-bilayer interactions. Various analytical techniques such as UV-Vis and fluorescence spectroscopy, Infrared spectroscopy, Fluorescence Anisotropy, Fluorescence resonance energy transfer (FRET), fluorescence microscopy and Mass spectrometry are being used to understand the subtle interaction occurring at bilayer surface. The objective of present study is to understand the protein-bilayers interactions at molecular levels.

Protein interactions at molecular levels: An investigative study of biomolecular reactions at bilayer surface

246th National Meeting (2013)

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