Phenylboronic Acid Modified Carbon Dots For Intracellular Delivery Of Proteins

Protein drugs play an important role in biomedicine,and some carriers including polymers have been developed to deliver proteins.However,due to differences in the molecular weight,isoelectric point and spatial structure of proteins,it is important to develop safe and effective intracellular delivery vehicles for proteins.In this paper,amine-rich carbon dots(CDs)were prepared and then modified with phenylboronic acid to synthesize CD-B.Research results prove that CD-B has high protein loading rate and intracellular delivery efficiency.The main research contents are as follows:First,polyethylenimine(PEI)and glyoxal were used as starting materials to synthesize CDs with amine groups on the surface by solvothermal method.The structure of CDs was characterized by transmission electron microscopy(TEM).The results showed that CDs are uniformly dispersed spherical particles with an average size of 11.4 nm.The emission spectrum proved that CDs have excellent luminescence properties.Next,CDs were modified with phenylboronic acid to obtain CD-B.CD-B still retains the optical properties of CDs.In addition,the detailed analysis of the functional groups and elemental composition of CD-B surface was characterized by Fourier transform infrared spectroscopy(FTIR)and X-ray electron spectroscopy(XPS).Bovine hemoglobin(Hb)and glucose oxidase(GOX)are selected as two model proteins.CD-B combined with Hb and GOX through a variety of non-covalent interactions to form Hb@CD-B and GOX@CD-B nanocomposites.TEM,UV-Vis absorption spectra,zeta potential,and electrophoresis analysis experiments confirmed that both of the proteins could be successfully loaded on CD-B.Next,a series of in vitro cell experiments proved that CD-B can be used as a protein carrier with extremely high affinity to deliver Hb and GOX into cells,and effectively maintain the biological activity of the protein.