Characterization of a UCST-type ion pair self-assembly sensitive to oxidation and its application as a gene vector

초록

An ion pair containing poly (allylamine) (PAA) and 4-(Methylthio)phenylacetic acid (MTPA) was prepared, which could self-assemble into nanoparticles in aqueous phase due to the electrostatic interaction between the amine group of PAA and the carboxyl group of MTPA. The spherical morphology of nanoparticles was captured by transmission electron microscopy (TEM) images. Ion pair self-assembly (IPSAM) exhibited UCST behavior and was sensitive to oxidation, with its UCST value decreasing as the degree of oxidation increased. The formation of salt bridges and the shift of proton peak signals were observed in FTIR and 1H NMR spectrum, respectively, confirming the interaction between PAA and MTPA. The oxidation of MTPA in IPSAM was further confirmed by XPS results. IPSAM, which is sensitive to temperature and oxidation, could release its payload as the temperature and degree of oxidation increased. This is attributed to the fact that IPSAM was disintegrated due to the loss of amphiphilicity as the temperature and degree of oxidation increased. Due to the excellent size and positive charge advantages of IPSAM, it can easily interact with siRNA and form IPSAM/RNA complexes. The IPSAM/ RNA complex exhibited good biocompatibility and significantly increased cellular uptake ability, making it a promising non-viral gene vector for gene therapy.

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