Surface Modified Metallic Orthopedic Implant for Sustained Drug Release and Osteocompatibility

Abstract

Designing implants with good antibacterial activity and simultaneously providing a platform for osteoblast adhesion is a challenge for researchers. All metallic implants, currently in use, are biocompatible but bioinert. This may lead to a weak interface with the bone and cause asceptic loosening. The aim of the present study is designing an implant with good antibacterial activity and simultaneously providing a platform for osteoblast adhesion. This is achieved by surface engineering of the currently used metallic implants without affecting their mechanical properties. The FDA approved plasma spraying technique is utilized to synthesize interconnected microporous bioactive hydroxyapatite (HA) coating on the Ti-6Al-4 V implant surface. The modified implant surface is impregnated with drug (gentamicin) loaded biodegradable polymer (chitosan) through a customized vacuum impregnation process. During impregnation, drug loaded polymer filled the pores of coating while leaving the rest of the HA surface exposed to promote osteoconductivity. The hardness and elastic modulus of the HA coating showed insignificant changes after impregnation with the drug loaded polymer, while the fracture toughness is improved by ∼42%. In vitro drug release studies have revealed a sustained release up to 180 h, with an ideal initial burst release. The drug loaded surfaces have also shown very efficient antibacterial activity against S. aureus, even after 5 days of incubation. Further, the modified surfaces have shown excellent osteocompatibility, due to the presence of the exposed HA coated surface. Thus, the surface modified implants, with a unique combination of antibacterial activity, osteocompatibility, and improved fracture toughness, have promising potential applications in orthopedics.

Poly-tetrahydropyrimidine Antibacterial Hydrogel with Injectability and Self-Healing Ability for Curing the Purulent Subcutaneous Infection

“…Antibiotics, known as a biologically functional molecule for killing bacteria, were severely restricted for the short-lasting effect and MDR in the clinic . Therefore, the long-term antibacterial assay of the hydrogels against S.…”

“…Antibiotics, known as a biologically functional molecule for killing bacteria, were severely restricted for the short-lasting effect and MDR in the clinic. 51 Therefore, the long-term antibacterial assay of the hydrogels against S. aureus was tested in comparison to the PNC-NSR, a commonly used antibiotics (Figure S9). Both PTHP-gel and PNC-NSR have effectively killed the bacteria in the first 12 h, but several bacterial colonies emerged on the inhibited areas after culturing for another 12 h, meaning the antibiotic has worn off.…”

Construction of Local Drug Delivery System on Titanium-Based Implants to Improve Osseointegration

“…They confirmed that the coating has stronger antibacterial and osteogenic properties than bare Ti [ 82 ]. Other studies suggested that Ti-based implants coated with hydroxyapatite (HA)/chitosan (Chi) composite coating had good local sustained release Gent ability, excellent biocompatibility, and osseointegration [ 83 , 84 ]. However, in order to extend the life of these Ti-based implants in patients, they were often necessary to add various additional antibiotics to prevent bacterial infection.…”

Construction of a Localized and Long-Acting CCN2 Delivery System on Percutaneous Ti Implant Surfaces for Enhanced Soft-Tissue Integration

“…Controllable micro/nano-rough Ti implant surfaces were prepared by anodic oxidation, hydrothermal treatment, etc ., introducing roughness, increased surface area, porosity, and improved wettability, which in turn could promote STI by enhancing adhesion, proliferation, and fibers secretion of soft-tissue cells. ,, However, single surface topographical alteration may not tackle the scenario that, after infection, the increased bacterial adhesion would compete with cell adhesion, thereby reducing the quality of STI. , Biofunctional coatings could be tailored toward specific cellular functions by immobilizing bioactive molecules onto the Ti implant surface to achieve STI augmentation . However, the drug-release rate of such biofunctional coating normally lacks control, and thus the coating would predispose to fail within a short period. , In our previous work, titania nanotubes (TNT) were prepared on pure Ti surfaces, and then cellular communication network factor 2 (CCN2) was loaded into TNTs by the lyophilization method to promote the biological response of fibroblasts . The CCN2-loaded TNT surface could promote fibroblast adhesion, viability, and actin cytoskeleton organization within 5 days, but the robust release of CCN2 in the first 15 min greatly reduced its long-term efficiency.…”

“…20 However, the drug-release rate of such biofunctional coating normally lacks control, and thus the coating would predispose to fail within a short period. 21,22 In our previous work, titania nanotubes (TNT) were prepared on pure Ti surfaces, and then cellular communication network factor 2 (CCN2) was loaded into TNTs by the lyophilization method to promote the biological response of fibroblasts. 23 The CCN2-loaded TNT surface could promote fibroblast adhesion, viability, and actin cytoskeleton organization within 5 days, but the robust release of CCN2 in the first 15 min greatly reduced its long-term efficiency.…”