Preparation And Biological Applications Of Fluorescent Conjugated Polymer Nanoparticles

In recent years, conjugated polymer nanoparticles(CPNs) have attracted considerable attentionbecause of their outstanding characteristics such as small particle size, high fluorescence brightness,excellent photostability, higher emission rates and lower toxicity. Semiconducting polymernanoparticles are prepared from conjugated polymer, so called CPNs. Based on these excellentproperties, CPNs applications in biology increasingly widespread. Besides the extensiveapplications in cellular imaging and immunofluorescent labeling, CPNs have demonstrated utility ina wide range of applications such as intracellular pH value, temperature sensing and metal iondetection. The authors carried out some originality and meaningful research work. Syntheticmaterials needed for the detection of biological molecules and cell markers targeted imaging. Theresults are summarized as follows:Designed and synthesized carboxyl-containing poly(phenylene vinylerm)(PPV-COOH). A fullspectrum of multi-colored PPV-COOH polymer solution (PPVseg-COOH) was obtained by a simpleheat treatment. The color change of PPVseg-COOH can be readily controlled by the addition of H2Oand the PL quantum efficiencies of PPVseg-COOH were obviously increased. The conjugatedpolymer nanoparticles (CPNs) with tunable photoluminescence colors and carboxylate groups havealso been successfully prepared by reprecipitation method. The carboxylate-functionalized CPNswere further covalently modified with streptavidin and the resulted PPVseg-SA CPNs couldeffectively and specifically labelled EpCAM receptors in MCF-7cancer cells. The syntheticmethods present the feasibility and flexibility for further developing surface-functionalizable CPNsprobes with full-color tunability for biological imaging and bioanalytical applications.Designed and synthesized carboxyl-containing polyfluorene (PF-COOH). The PF-COOHCPNs with carboxylate groups have also been successfully prepared by reprecipitation method.Based PF-COOH CPNs a new and simple bioconjugate-recognized DNA sensor was builded. Theadvantages of this design is that it does not utilize the electrostatic attraction of CPEs to detectanionic DNA and the CPNs sensors can improve detection sensitivity due to increased interchaininteractions and more efficient exciton transport in nanoparticles. The covalent DNA coating canalso significantly improves the photostability of the DNA-bioconjugated CPNs over a wide range ofbuffer conditions, which is desirable for many applications and allows CPNs to be used underphysiologically relevant environments. The further significance of this sensing systemis that intercalating dye Picogreen are used in combination with the DNA-bioconjugated CPNs to developlabel-free DNA sensors and thus a detection concentration as low as nanomolar could be achievedin serum.