Rice-husk-templated hierarchical porous TiO(2)/SiO(2) for enhanced bacterial removal

Improvements of Corrosion Resistance and Antibacterial Properties of Hydroxyapatite/Cupric Oxide Doped Titania Composite Coatings on Degradable Magnesium Alloys

The excellent biocompatibility of calcium phosphate (CaP) coatings makes them widely used in magnesium (Mg) alloy orthopedic implant materials. However, the porous morphology of CaP coatings limits their corrosion resistance. A cupric oxide (CuO) doped titania (TiO₂) sol-gel coating is prepared on a porous hydroxyapatite (HA) coating. According to electrochemical test results, the HA/CuO-TiO₂ coating obtains a current density of 6 × 10^-4 mA/cm², lower than that of the Mg alloy (2.6 × 10^-2 mA/cm²). The hydrogen evaluation of the HA/CuO-TiO₂ coating is only 1/12 that of the Mg alloy after immersion for 7 days. In addition, the HA/CuO-TiO₂ coating has an antibacterial rate of 99.5 ± 0.4% against Staphylococcus aureus, significantly higher than that of the HA coating (19.8 ± 0.3%) and HTC0 coating (38.4 ± 0.5%). The CuO doped composite coating has no adverse effect or cytotoxicity on cell proliferation (cell viability ≥79.6%). Hence, the HA/CuO-TiO₂ composite coating is useful for enhancing the corrosion resistance and antibacterial properties of Mg alloys while ensuring cytocompatibility. The HA/CuO-TiO₂ coated AZ60 Mg alloy can meet the requirements of clinical application.

Covalent grafting of hyperbranched poly-L-lysine on Ti-based implants achieves dual functions of antibacteria and promoted osteointegration in vivo

The dual functional implants of antibacteria and osteointegration are highly demanded in orthopedic and dentistry, especially for patients who suffer from diabetes or osteoporosis simultaneously. However, there is lack of the facile and robust method to produce clinically applicable implants with this dual function although coatings possessing single function have been extensively developed. Herein, hyperbranched poly-L-lysine (HBPL) polymers were covalently immobilized onto the alkali-heat treated titanium (Ti) substrates and implants by using 3-glycidyloxypropyltrimethoxysilane (GPTMS) as the coupling agent, which displayed excellent antibacterial activity against S. aureus and E. coli with an efficiency as high as 89.4% and 92.2% in vitro, respectively. The HBPL coating also significantly promoted the adhesion, spreading, proliferation and osteogenic differentiation of MC3T3-E1 cells in vitro. Furthermore, the results of a S. aureus infection rat model in vivo ulteriorly verified that the HBPL-modified screws had good antibacterial and anti-inflammatory abilities at an early stage of implantation and better osteointegration compared with the control Ti screws.

Sawdust as an effective biotemplate for the synthesis of Ce0.8Zr0.2O2 and CuO–Ce0.8Zr0.2O2 catalysts for total CO oxidation

The high catalytic efficiency of biomorphic systems can be explained by the unique texture and effect of ash impurities (K, Ca).

Hierarchically porous materials: synthesis strategies and structure design

This review addresses recent advances in synthesis strategies of hierarchically porous materials and their structural design from micro-, meso- to macro-length scale.

Hierarchical photocatalysts

The design, fabrication, performance and applications of hierarchical semiconductor photocatalysts are thoroughly reviewed and apprised.

Bioinspired anchoring AgNPs onto micro-nanoporous TiO2 orthopedic coatings: Trap-killing of bacteria, surface-regulated osteoblast functions and host responses

The therapeutic applications of silver nanoparticles (AgNPs) against biomedical device-associated infections (BAI), by local delivery, are encountered with risks of detachment, instability and nanotoxicity in physiological milieus. To firmly anchor AgNPs onto modified biomaterial surfaces through tight physicochemical interactions would potentially relieve these concerns. Herein, we present a strategy for hierarchical TiO2/Ag coating, in an attempt to endow medical titanium (Ti) with anticorrosion and antibacterial properties whilst maintaining normal biological functions. In brief, by harnessing the adhesion and reactivity of bioinspired polydopamine, silver nanoparticles were easily immobilized onto peripheral surface and incorporated into interior cavity of a micro/nanoporous TiO2 ceramic coating in situ grown from template Ti. The resulting coating protected the substrate well from corrosion and gave a sustained release of Ag(+) up to 28 d. An interesting germicidal effect, termed "trap-killing", was observed against Staphylococcus aureus strain. The multiple osteoblast responses, i.e. adherence, spreading, proliferation, and differentiation, were retained normal or promoted, via a putative surface-initiated self-regulation mechanism. After subcutaneous implantation for a month, the coated specimens elicited minimal, comparable inflammatory responses relative to the control. Moreover, this simple and safe functionalization strategy manifested a good degree of flexibility towards three-dimensional sophisticated objects. Expectedly, it can become a prospective bench to bedside solution to current challenges facing orthopedics.