Preparation and Properties of Physical Gel on Medical Titanium Alloy Surface

Medical titanium alloy Ti-6Al-4V (TC4) has been widely used in the medical field, especially in human tissue repair. However, TC4 has some shortcomings, which may cause problems with biocompatibility and mechanical compatibility in direct contact with the human body. To solve this problem, physical gels are formed on the surface of TC4, and the storage modulus of the formed physical gel matches that of the human soft tissue. 2-bromoisobutyryl bromide (BIBB) and dopamine (DA) were used to form initiators on the surface of hydroxylated medical titanium alloy. Different initiators were formed by changing the ratio of BIBB and DA, and the optimal one was selected for subsequent reactions. Under the action of the catalyst, L-lactide and D-lactide were ring-opened polymerized with hydroxyethyl methacrylate (HEMA), respectively, to form macromolecular monomers HEMA-PLLA₂₉ and HEMA-PDLA₂₉ with a polymerization degree of 29. The two macromolecular monomers were stereo-complexed by ultrasound to form HEMA-stereocomplex polylactic acid (HEMA-scPLA₂₉). Based on two monomers, 2-(2-methoxyethoxy) ethyl methacrylate (MEO₂MA) and oligo (ethylene oxide) methacrylate (OEGMA), and the physical crosslinking agent HEMA-scPLA_29, physical gels are formed on the surface of TC4 attached to the initiator via Atom Transfer Radical Addition Reaction (ATRP) technology. The hydrogels on the surface of titanium alloy were characterized and analyzed by a series of instruments. The results showed that the storage modulus of physical glue was within the range of the energy storage modulus of human soft tissue, which was conducive to improving the mechanical compatibility of titanium alloy and human soft tissue.