Multifunctional Supramolecular Polymer Nanoparticles For Ratiometric Oxygen Sensing And Photodynamic Cancer Therapy

Oxygen deprivation(hypoxia)has been found to be connected with a variety of diseases,such as cancer,cardiovascular diseases,stroke,Alzheimer's and Parkinson's diseases.Thus,the measurement of oxygen levels in living cells and tissue is critical to diagnosing cancer.Ratiometric optical oxygen sensing based on phosphorescence quenching is highly appreciated due to its good sensitivity and selectivity,full reversibility and minimal consumption of oxygen during measurements.Photodynamic therapy(PDT)has been developed as one of the most powerful methods in cancer therapy,which is,for certain cancers,superior to chemotherapeutic ways with fewer side effects,causes negligible drug resistance and has low systemic toxicity.Therefore,the development of multifunctional oxygen sensor with photodynamic therapy has great significance.Supramolecular polymer,which are prepared from low-molecular-weight monomeric units that are associated through reversible noncovalent interactions can be efficiently incorporated by copolymerization and provide a promising basis to fabricate ratiometric optical oxygen sensing.This thesis can be divided into the following three parts:1.The phosphorescent Por(Pt)-bisUPy and fluorescent DPA-bisUPy were synthesized and characterized by 1H NMR,13 C NMR and high resolution mass spectra.The photophysical properties of these two compounds demonstrate them as excellent candidates in ratiometric optical oxygen sensing.2.NMR spectroscopy and viscosity test showed that DPA-bisUPy and Por(Pt)-bisUPy could form supramolecular polymer chains in chloroform.Three kinds of supramolecular nanoparticles NP1,NP2 and NP3 were fabricated by the microemulsion method.These nanoparticles were characterized by SEM and TEM with the average size about 60 nm,confirming their uniform shape and size.There was an efficient energy transfer between the energy donor(DPA-bisUPy)and the energy receptor(Por(Pt)-bisUPy),and the phosphorescence of the oxygen sensor was significantly enhanced.Oxygen quenching results indicate that it is not only a ratiometric optical oxygen sensor but also a colorimetric optical oxygen sensor.3.The cytotoxicity and photostability test showed that the supramolecular-polymer-based nanoprobe for ratiometric oxygen sensing has favourable biocompability and photostability,and could be used for PDT therapy and cellular oxygen imaging.