A functional coating to enhance antibacterial and bioactivity properties of titanium implants and its performance in vitro

Abstract

Bacterial infections and lack of osseointegration may negatively affect the success of titanium (Ti) implants. In the present study, a functional coating composed of chitosan (CS) microspheres and nano hydroxyapatite (nHA) was prepared to obtain antimicrobial Ti implants with enhanced bioactivity. First, the chitosan microspheres were fixed to Ti surfaces activated by alkali and heat treatment, then nHA coatings were precipitated onto these surfaces. Ciprofloxacin was loaded into the microspheres using two different procedures; encapsulation and diffusion. Scanning electron microscopy micrographs of the modified Ti surfaces showed that the coating was successfully deposited onto the Ti surfaces and stable for 30 days in PBS. The drug was completely released from free microspheres loaded by encapsulation in 21 days whereas only 89% release was observed after immobilization. The burst release also decreased from ca. 55% to ca. 35%. The release was further reduced following the nHA precipitation. The modified Ti surfaces showed antimicrobial activity based on the bacterial time-kill assay using S. aureus, but the efficiency was affected by both nHA precipitation and drug loading strategy. Highest antimicrobial activity was seen in the samples without nHA layer, and when the drug was loaded by diffusion. Fourier transform infrared spectroscopy and X-ray diffraction analyses revealed that nHA on the surface enhanced HA growth in simulated body fluid for 3 weeks, showing increased osseointegration potential. Therefore, the proposed coating may be used to prevent Ti implant failure originated from bacterial infection and/or low bioactivity.

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

“…They demonstrated that the release of chlorhexidine could facilitate osseointegration by completely preventing the formation of bacterial biofilm on the implant surface [ 96 ]. In addition, the failure of osseointegration caused by bacterial infection could be prevented by direct grafting of antibiotic ciprofloxacin on Ti implants or by loading ciprofloxacin on CS/nanoHA/Ti [ 97 , 98 ]. In order to obtain more superior antibacterial implants, Park et al loaded silver nanoparticles, cephalothin, minocycline (Mino), and amoxicillin on mesoporous TiO 2 .…”

“…Furthermore, some researchers used ALN/HA/TNT as a nanorepository of antiosteoporosis drug raloxifene (Ral) to coordinate the regulation of osteoclasts and osteoblasts. It is worth mentioning that Ral had no side effects on the uterus and breast [ 97 ]. They found that the implant effectively decreased the activity of osteoclasts and enhanced the activity of ALP and mineralization ability of osteoblasts [ 122 ].…”

A review onin vitro/in vivoresponse of additively manufactured Ti–6Al–4V alloy

“…As mentioned previously, surface properties such as charge, wettability, roughness, and chemical composition are the main factors affecting biomaterial-cell interactions. 415,457,458 However, some research findings confirmed that defining nanotopographies are more effective in preventing biofilm formation and amelioration of antimicrobial resistance. 412 For example, creating topographies with sharp edges (such as nano spikes and nanopillars) on the implant surface generates local stresses across the microbial cell membrane, which can ultimately lead to bacterial lysis.…”

Overview of Antibacterial Strategies of Dental Implant Materials for the Prevention of Peri-Implantitis

“…94 The combination of osteogenically active hydroxyapatite and chitosan, which has sustained drug release ability, can improve both biocompatibility and antibacterial properties. 95 Chitosan is a cationic polysaccharide polymer with excellent biocompatibility and inherent antibacterial activity. 96−98 Chitosan can also be loaded with antibiotics and metal particles as the carrier of drug delivery system in surface modification.…”

“…For example, although hydroxyapatite can carry and release a variety of antibiotics, it lacks the ability to control the release rate, especially during the initial period, resulting in poor biocompatibility and only short-term antibacterial effects . The combination of osteogenically active hydroxyapatite and chitosan, which has sustained drug release ability, can improve both biocompatibility and antibacterial properties . Chitosan is a cationic polysaccharide polymer with excellent biocompatibility and inherent antibacterial activity. − Chitosan can also be loaded with antibiotics and metal particles as the carrier of drug delivery system in surface modification.…”