In this report, protein repelling silicone hydrogels with improved hydrophilicity were prepared by photo-polymerization of silicone-containing monomer and glycidyl methacrylate followed by grafting zwitterionic amino acids. The grafted silicone hydrogels possessed excellent hydrophilic surfaces due to the enrichment of amino acids, which was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle, and equilibrium water content measurements. Remarkable resistance to bovine serum albumin and lysozyme fouling was observed for the silicone hydrogels immobilized with neutrally charged amino acids because of the formation of zwitterionic surfaces with pairs of protonated secondary ammonium cations and deprotonated carboxyl anions. Meanwhile, the silicone hydrogels grafted with positively or negatively charged amino acids were able to repulse same charged protein with reduced deposition and attract oppositely charged protein with increased adsorption. Preliminary cytotoxicity test indicated that the zwitterionic silicone hydrogels were non-cytotoxic. Similarly, three types of natural amino acids, including serine, aspartic acid and histidine, modified silicone hydrogel contact lenses exhibited excellent hydrophilicity and non-damage to the rabbit's eyes, but only serine modified zwitterionic contact lens showed superior protein fouling resistance compared with the current commercial hydrogel contact lens, which may have great potential application in ophthalmology.
Chlorambucil is a classic nitrogen mustard drug that has been used in the treatment of cancers. It may induce neutropenia, thrombocytopenia and other side effects because of its short lifetime and off‐target effect. In this report, chlorambucil‐tetrapeptide (AAAK, A3K) conjugate vesicles were developed to improve the stability and bioactivity of chlorambucil. First of all, chlorambucil‐A3K conjugate was synthesized by solid phase synthesis strategy. Secondly, the chlorambucil‐A3K conjugate was assembled and characterized by critical aggregation concentration, circular dichroism, dynamic light scattering and transmission electron microscopy. The results indicated that the chlorambucil‐A3K conjugate can be assembled to form spherical vesicles with an average diameter of 390.5 nm, and high drug loading about 47.1% is reached. Surprisingly, the preliminary biological evaluation of the chlorambucil‐A3K conjugate vesicles revealed the best in vitro anticancer activity against HeLa, HepG‐2 and MCF‐7 cell lines compared with chlorambucil and chlorambucil‐A3K conjugate free drugs. Furthermore, conjugate vesicles showed excellent in vivo antitumoral activity. It can be partly attributed to their vesicular structure which isolates chlorambucil active moiety from aqueous solution to retard degradation before killing cancer cells. Therefore, chlorambucil‐peptide (A3K) conjugate vesicles may be an alternative delivery system of chlorambucil.
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