Strategies toward Highly Sensitive Polydiacetylene Supramolecules based Biosensors.

[摘要] Polydiacetylene (PDA) based biosensors have the merits of colorimetric and fluorometric dual signaling and self-assembly based easy fabrication. In this dissertation, the signal generating mechanism of PDA liposomes was first systematically studied by investigating target size effect on the sensory signaling intensity of PDA liposome sensors. Influenza A virus M1 peptide and M1 antibody were selected as a probe-target pair but their role was switched in two different types of sensory system. When the larger M1 antibody was used as a target and M1 peptide was tethered at the liposome surface as a probe, a detectable sensory signal was generated. However, if their roles are switched no sensory signal was observed, revealing that the intensity of the PDA sensory signal is mainly related to the steric repulsion between probe-target complexes, not the strength of the probe-target binding force. In order to enhance the sensitivity, phospholipids were inserted into the PDA liposome to provide fluidic mobility within the PDA liposome structure, enabling easy distortion of the PDA backbone.PDA liposomes are known to easily accommodate various phospholipids. If phospholipids are utilized as the capturing moiety for target analytes, recognition events at the PDA liposome surface can distort PDA intermolecular packing and produce sensory signals. While these PDA-phospholipid supramolecules were studied, a very unique phenomenon of Rhodamine6G (R6G) quenching with a phospholipid (1,2-dimyristoylsn-glycero-3-phosphate, DMPA) aqueous solution was discovered. Coulombic interaction between cationic R6G and the anionic DMPA phospholipid occurred in the aqueous phase and created spherical liposome structures. At the surface of the liposome, the R6G molecules are H-type aggregated on the head groups of DMPA and their emission is quenched. Based on this finding, a highly sensitive and selective new sensing platform was devised by co-assembling PDA and phospholipids that displays specific interactions with a target bioanalyte.Matrix polymer-assisted sensitive PDA sensory system and 1-dimensional PDA nanofibers are also studied to enhance colorimetric sensitivity of PDA systems. Hygroscopic alginate polymer films having embedded PDA liposomes and PDA nanowires are prepared, respectively, and were used to investigate a matrix-assisted sensory platform and the effect of dimensionality of PDA on sensory signaling properties.

[发布机构] University of Michigan

[效力级别] Biosensors

[关键词] Polydiacetylene Supramolecules;Biosensors;Materials Science and Engineering;Engineering;Science;Macromolecular Science & Engineering