Bioinspired Surface Functionalization of Titanium for Enhanced Lubrication and Sustained Drug Release

Abstract

Titanium and its alloys have long been used as implantable biomaterials in orthopedics; however, to the best of our knowledge, few studies were reported to investigate surface functionalization of titanium for enhanced lubrication and sustained drug release. In the present study, titania nanotube arrays (TNTs) were prepared by anodization as effective drug nanocarriers, using titanium as the substrate. Meanwhile, motivated by articular cartilage-inspired superlubricity and mussel-inspired adhesion, a copolymer containing both dopamine methacrylamide and 2-methacryloyloxyethyl phosphorylcholine was synthesized (DMA−MPC) and spontaneously grafted onto the TNT surface, which was validated by characterization techniques such as scanning electron microscopy, water contact angle measurements, and X-ray photoelectron spectroscopy. Additionally, the lubrication test showed that copolymer-grafted TNTs have remarkably reduced friction coefficients compared with bare TNTs. Furthermore, the drug release test demonstrated that copolymer-grafted TNTs inhibited burst drug release and achieved sustained drug release in comparison with bare TNTs. In conclusion, the bioinspired surface functionalization strategy developed here, namely DMA−MPC copolymer-grafted TNTs, can be applied to modify orthopedic biomaterials (such as titanium) for enhanced lubrication and sustained drug release.

Bioinspired Surface Functionalization of Titanium Alloy for Enhanced Lubrication and Bacterial Resistance

“…The DMA–MPC copolymer was synthesized with reference to our previous studies. , Briefly, dopamine methacrylamide (DMA) was initially prepared by an amidation interaction between dopamine hydrochloride and methacrylic anhydride using NaB 4 O 7 as catechol group protector and NaHCO 3 as acid binding agent. Subsequently, the DMA–MPC copolymer was prepared via free radical copolymerization of DMA and MPC (feeding mole ratio 1:4) using AIBN as the initiator.…”

“…In our previous studies, motivated by articular cartilage-inspired superlubrication and mussel-inspired adhesion, − we successfully synthesized a copolymer (DMA–MPC) for surface functionalization of nanodiamonds and titania nanotube arrays. , The spontaneous adhesion between the DMA–MPC copolymer and various substrates was achieved, indicating that the copolymer could be employed as a versatile approach for multifunctional purpose. More importantly, this method is nontoxic and independent of the type, size, and shape of the substrate and consequently appropriate for surface modification of biomedical implants compared to traditional chemical synthesization techniques .…”

Synthesis of articular cartilage‐inspired branched polyelectrolyte polymer for enhanced lubrication

“…As depicted in Fig. 4, the zwitterionic charges in PMPC can attract several water molecules to form a tenacious hydration shell surrounding the phosphorylcholine group, which is responsible for the low COF tested under aqueous conditions [22, 23]. Specifically, it is difficult for the hydration shells to overlap with each other due to the steric effect, and the lower Gibbs free energy of the water molecules in the hydration shells makes it difficult for them to deform, and consequently, the hydration shells can undergo a large normal pressure without deformation.…”

Fabrication of a Hydrophilic Low-Friction Poly(hydroxyethyl methacrylate) Coating on Silicon Rubber

“…Silicon rubber is strongly hydrophobic and chemically inert, so it is difficult to directly coat hydrophilic materials on its surface. However, coating a coupling agent on the surface of silicon rubber or improving the adhesion of hydrophilic materials can enhance the adhesion ability of coatings on the surface of silicon rubber. − For example, catechol functional groups were used to modify hydrophilic polymers (chitosan and hyaluronic acid) to enhance their adhesion performance, and the catechol-functionalized hydrophilic polymers were deposited on the surface of the catheter . These polymers significantly enhanced the hydrophilicity of the catheter compared to its uncoated surface.…”