Biocompatibility Of PNNS Nanoparticles And Its Application

Previous studies have shown that poly (N-isopropylacrylamide) (PNIPAAm) possesses special temperature responsibility and biocompatibility. It has been wildy investigeted due to its potential applications in numerous fields such as drug delivery, biosensor and biochemical separation and so on. In this paper, poly (N-isopropylacrylamide-co-styrene)-g-poly (N-isopropylacrylamide) nanoparticles (PNNS-NPs) were synthesized. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) and Zeta potential were used to study the morphology and structure of PNNS-NPs. UV-vis absorption spectra, fluorescence microscope (FL), circular dichroism (CD) and electrochemical methods were used to investigate the interaction between PNNS-NPs and hemoglobin (Hb). Inverted fluorescence microscope, whole-cell patch clamp technique and non-electric activity of ion detection were used to research the cytocompatibility of PNNS-NPs to the HEK-293 cell. The process and mechanism of the interaction between PNNS-NPs and Hb or HEK-293 were investigated on proteinic and cellular level. The results can provide theoretical and experimental basis for the application in biomedical field of PNNS-NPs.The main results are as follows:1) The structure of PNNS-NPs is core-shell and the average size of PNNS-NPs is about 150-200 nm. PNNS-NPs have uniform size, good dispersion and electronegativity.2) There are some weak interactions between PNNS-NPs and Hb. The micro structure of Hb has some minor changes, while the secondary conformation of Hb has not been significantly affected, the active center of it has not been destroyed and the physiological function of it has been maintained.3) PNNS-NPs could enrich to the surface of cell without destroying the normal morphology of cell and affectting the transmembrane transport of potassium ion in cell membrane after PNNS-NPs contacting with HEK-293 cells. HEK-293 cell can maintain its normal function and adapt PNNS-NPs gradually.4) To be one of the biocompatibility applications of PNNS-NPs, this article discussed the significance of PNNS-NPs as a kind of biosensor materials. After a series of electrochemical examinations, it demonstrated that PNNS-NPs could prevent the MWCNTs to contact with Hb directly and provided a friendly microenvironment to retain Hb’s bioactivity. Thus, the Hb/PNNS-NPS/MWCNTs/GCE biosensor shows good electrochemical performance, such as high sensitivity and wide detection range. It has acceptable fabrication reproducibility and storage stability.