Organic-inorganic Hybrid Thermo-Sensitive Materials Control The Aggregation Induced Luminescence Properties Of TPE

Fluorescence imaging technique has gained considerable attention due to its advantages of high sensitivity,superfast response and a non-invasive approach.As a typical AIE molecule,tetraphenylethene(TPE)exhibits high sensitivity to environmental changes and has been widely used in many fields.As biological events are often accompanied with a variation in body temperature,it is desirable to develop fluorescent probes sensitive to temperature change.In this study,an organic-inorganic temperature-sensitive polymer encapsulating tetraphenylethene(TPE)was designed.Its fluorescent intensity is sensitive to the temperature change and reaches the maximum at normal cell temperature.Firstly,organic-inorganic hybrid polymer,polyhedral oligomeric silsesquioxane-based-poly(N-isopropylacrylamide)(POSS-b-PNIPAM)with a particular LCST of 37.5 °C,was synthesized by atom transfer radical polymerization.The LCST of the polymer is close to the cell temperature of the organism.POSS-b-PNIPAM self-assembled in aqueous solutions to form stable micelles and then TPE was assembled into the micelles in water.The fluorescence intensity of TPE encapsulating in POSS-b-PNIPAM can be tuned by changing the temperature.The fluorescence intensity of TPE encapsulating in POSS-b-PNIPAM achieved the maximum at 37 °C that is much higher than TPE fluorescence intensity at the same temperature.Because 37 °C closest to the temperature of cells in the body,which is very important for the biological probe,biological detection and other aspects.TPE encapsulating in POSS-b-PNIPAM still showed high fluorescence intensity after entering into HeLa cells at 37 °C.DLS was tested at different temperatures which further proved that the fluorescence intensity reached the maximum mechanism at 37 °C.In the organic-inorganic hybrid POSS-b-PNIPAM polymer,the different length of PNIPAM makes the polymer have different LCST.In the POSS-b-PNIPAM of PNIPAM assembled in different segments,it was found that the longer the PNIPAM segment,the larger the DLS,the lower the LCST and the weaker the fluorescence intensity.