| A luminescent, conjugated polyelectrolyte, Lithium Poly [5-methoxy-2-(4-sulfobutoxy)-1,4-phenylene-vinylene] (MBL-PPV) was synthesized via a new, short route.; The photoluminescence quenching of conjugated polyelectrolyte, MBL-PPV, by 4,4′-dipyridyl and six bipyridinium derivatives, was studied. The quenching mechanism was studied by examining UV-visible spectra, by studying PL quenching with the addition of salts and by studying the temperature dependence of PL and PL quenching. Dynamic and sphere-of-action quenching were found for the neutral quenchers and charged quenchers, respectively.; Using multi-angle static light scattering (SLS) and small angle neutron scattering (SANS), the solution behaviors of the conjugated polyelectrolyte, MBL-PPV, were studied under various conditions, such as different concentrations, different ionic strength (salt concentrations), different quenchers, and surfactant.; A series of quencher (methyl viologen based) with the functionality targeting to the thiol groups on proteins, were synthesized and methyl viologen was bio-conjugated onto the sheep anti-mouse Fab' fragment. Fab'-Q is a very effective quencher for anionic MBL-PPV. An anionic quencher, DNP-BS− was made for the quenching of a cationic conjugated polyelectrolyte, with DNP moiety serves uniquely as both quencher and bio-active ligand.; The conjugated polyelectrolytes used in the biosensor study were found to associate with negatively charged biopolymers (proteins). The PL efficiency of the polyelectrolyte is enhanced or reduced for the anionic or cationic conjugated polyelectrolyte. To overcome the non-specific interaction between the conjugated polyeletrolytes and bio-polymers, energy transfer complex (ETC) was formed by a blue emitting cationic and a orange emitting anionic conjugated polyelectrolytes. By tuning the charges on the conjugated polyelectrolyte, the attenuation of the nonspecific effects on the PL was achieved. The PL from the ETC can be quenched by both cationic and anionic quenchers. The ETC concept can be extended to a broader charge tuning system where only one polyelectrolyte is emissive.; MV2+ was also linked onto the oligonucleotides, and the bio-conjugated quencher, DNA-Q, shows good quenching of the PL from anionic MBL-PPV in buffer solution. DNA strongly enhances of the PL from conjugated MBL-PPV. Future work involved using the ETC, which has the minimized interaction between the biopolymer (DNA) and conjugated polyelectrolyte as the DNA biosensor. |
