Bioactive titanium metal surfaces with antimicrobial properties prepared by anodic oxidation treatment

Surface modification techniques of titanium and titanium alloys for biomedical orthopaedics applications: A review

Biomedical alloys have an important share in orthopedic applications. Among them, titanium and its titanium alloys are widely used as implant materials because of their excellent mechanical properties and non-cytotoxicity. However, its disadvantages such as its biological inertness and poor antibacterial properties inhibit its further development. Therefore, the surface properties of titanium are crucial in the implantation process and determine the success of the implant. The main purpose of this review is to provide a comprehensive and detailed description of the modification techniques used for the surface modification of titanium implants. In this paper, the corresponding technical methods are introduced systematically from four aspects: mechanical method, physical surface modification, chemical surface modification and electrochemical technique to understand the experimental mechanism of each modification technique, and the above methods can indeed improve the various properties of titanium and its alloys. With the increasing demand for implants in the future, the requirements for surface properties will also increase. Therefore, the development of new coating materials with higher performance by combining various advantages of existing modification technologies is the main trend of future research on surface modification of titanium alloys.

Effects of statherin on the biological properties of titanium metals subjected to different surface modification

The failure of dental implants is usually caused by bacteria infection, poor bioactivity and biocompatibility. It is a common phenomenon clinically. Statherin, a salivary protein, plays a crucial role of mediator between materials and cells/bacteria. However, the conformation of statherin might be changed by the implants in vivo. In this study, we investigated the effects of statherin on the bioactivities, antibacterial abilities and biocompatibilities of the titanium metals and the reaction mechanism. We found that the conformation of statherin was mainly influenced by surface composition, surface structure, surface roughness, surface hydrophilia and Ti-OH groups of materials. Statherin could decrease the cell biocompatibility of the titanium metals including pure titanium (PT), anodic oxidation (AO), sandblasting and etching (SLA) and plasma spraying hydroxyapatite (HA) coating in HGF cell experiments, regulate the bio-mineralization ability of HA coating in SBF, and enhance the antibacterial properties of PT and HA coating. This study revealed that surface properties of materials could change the conformation of statherin, which influenced the bioactivities, antibacterial properties and biocompatibilities of the materials in return.

Hypromellose succinate-crosslinked chitosan hydrogel films for potential wound dressing

The objective of this study was to develop novel hydrogel films based on carboxyl-modified hypromellose-crosslinked chitosan for potential wound dressing. Hypromellose (HPMC) was grafted with succinic acid to yield hypromellose succinate (HPMCS), and then the reinforced hydrogel films of HPMCS-crosslinked chitosan (HPMCS-CS) were prepared through amide bond formation using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N- hydroxysuccinimide (NHS) as a catalyst. Compared to that of blend film, mechanical properties of HPMCS-CS hydrogel films were significantly enhanced both in dry and swollen state. To assess the applicability of HPMCS-CS hydrogel films as wound dressing, the swelling behavior, water vapor transmission rate (WVTR), oxygen permeability, biocompatibility (cytotoxicity and hemolysis), in vitro drug release and bactericidal properties were analyzed. The results indicated that HPMCS-CS hydrogel films with good biocompatibility possess high swelling ratio, proper WVTR, and oxygen permeability, which might accelerate tissue regeneration. Meanwhile, gentamycin sulfate release from drug-loaded HPMCS-CS hydrogel films were sustained, which would help to protect wound from infection.

Carboxyl-modified poly(vinyl alcohol)-crosslinked chitosan hydrogel films for potential wound dressing

The objective of this study was to develop a novel carboxyl-modified poly(vinyl alcohol)-crosslinked chitosan hydrogel films for potential wound dressing. To prepare the crosslinked hydrogels, poly(vinyl alcohol) (PVA) was grafted with succinate acid to yield carboxyl-modified poly(vinyl alcohol) (PVA-COOH). Hydrogel films based on PVA-COOH and chitosan (CS) at different concentrations were crosslinked through the formation of amide linkages. The mechanical properties of these crosslinked hydrogel films in dry and swollen state were greatly improved with high swelling ratio. Water vapor and oxygen permeability evaluations indicated that crosslinked hydrogel films could maintain a moist environment over wound bed. Biocompatibility test showed the crosslinked hydrogels had no cytotoxicity and hemolytic potential. Gentamicin sulfate-loaded crosslinked hydrogel films showed sustained drug release profile, and could effectively suppress bacterial proliferation and protect wound from infection.

Survival and transmission of community-associated methicillin-resistant Staphylococcus aureus from fomites

BACKGROUND

Transmission of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) from fomites appears to play an important role in CA-MRSA outbreaks. However, the amount and duration of transmissibility of MRSA have not been quantified.

METHODS

We assessed the survival and transmission of the CA-MRSA strain USA300-0114 from 9 fomites (razors, plastic toys, ceramic, soap, wood, vinyl, towels, bed sheets, and shoulder pads). Fomites were inoculated then briefly pressed onto sterile pigskin at 5 minutes; days 1, 2, 3, 7, and 10; and then weekly for 10 weeks. The experiment was repeated using 2 methicillin-susceptible S aureus (MSSA) and 3 health care-associated (HA) MRSA strains on select fomites.

RESULT

Bacteria could be transmitted to skin from all fomites except soap. Transmissibility decreased over time but more rapidly from porous (eg, towels) than nonporous (eg, vinyl) fomites (P = .0002), with some fomites showing transmissibility for more than 8 weeks after contamination. The CA-MRSA strain was transmissible longer than the HA-MRSA strains (P < .0001) and 1 MSSA strain.

CONCLUSION

CA-MRSA strains are transmissible from many fomites to skin with contaminated nonporous fomites exhibiting transmissibility many weeks after contamination. Transmissibility of HA-MRSA strains demonstrated attenuated transmissibility compared with CA-MRSA strains. Findings may have implications for CA-MRSA infection prevention.