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Metals play an essential role in biochemistry, and the use of metals for antimicrobial applications has been well studied. Biomaterials incorporating copper and silver demonstrated high antimicrobial activity while maintaining good cytocompatibility. In this overview, nanostructure processing is underscored as a method to overcome the shortcomings of conventional bioceramics. Restructuring crystalline structures at the nanoscale make it less susceptible to brittle fracture. Furthermore, the bioactivity of the material is significantly improved through nanoscale surface modifications such as coatings. The effectiveness of nanostructured biomaterials featuring copper and silver in combatting bacterial attachment and proliferation is described. Nanoscale copper-containing stainless steel achieved antimicrobial activity by disrupting bacterial metabolism and damaging bacterial membranes while providing a conducive environment for cellular proliferation. Copper-containing stainless steels can be used to prevent marine corrosion, food preservation and combat implant-related infections. It is envisaged that future antimicrobial strategies will continue to feature copper and silver nanostructured biomaterials prominently. [ABSTRACT FROM AUTHOR]

This study aims to develop new quaternary ammonium salt-based antimicrobial materials with good biocompatibility, biosafety, and strong antimicrobial properties that promote wound healing in infected wounds. First, four new quaternary ammonium salt antibacterial fibers (QASAF) are constructed: QASAF-C12, QASAF-C14, QASAF-C16, and QASAF-C18, with varying carbon chain lengths of C12, C14, C16, and C18, respectively. Then, their structure is characterized by proton nuclear magnetic resonance (NMR) analysis and their hemolytic and cytotoxic properties are also investigated. QASAFs are then evaluated for in vivo and in vitro antimicrobial performance against Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus (MRSA). Finally, the effect of QASAF on promoting wound healing in infected wounds is evaluated using mouse wound models infected with S. aureus and MRSA. The obtained results suggest that QASAF is non-toxic to cells in the 25–125 µg/mL concentration range, is slightly hemolytic, has good biocompatibility, and has a biosafety profile. QASAF-C18 shows the best antibacterial performance against S. aureus with significant pro-healing effects on infected wounds. QASAF-C12 exhibits the best antibacterial performance against MRSA with significant pro-healing effects. The novel quaternary ammonium-based antimicrobial material provides a reference for developing antimicrobial and biocompatible wound dressings. [ABSTRACT FROM AUTHOR]

Quaternary ammonium (QA) methacrylate monomers have been extensively investigated and demonstrate excellent antibacterial properties. However, the presence of ester bonds makes them prone to degradation in the oral cavity. In this study, ester-free QA monomers based on meth-acrylamides were synthesized and screened for polymerization kinetics, mechanical properties and antibacterial effects. Tertiary quaternary ammonium acrylamides (AM) and methacrylamides (MAM) with alkyl side chain lengths of 9 and 14 carbons (C9 and C14) were synthesized and incorporated at 10 wt% into experimental composites based on BisGMA:TEGDMA (1:1), camphorquinone/ethyl-4-dimethylaminobenzoate (0.2/0.8 wt%) and 70 wt% barium glass fillers. Analogous methacrylate versions (MA) were used as controls. Degree of conversion (DC) and rate of polymerization (RP) during photoactivation (800 mW/cm2) were followed in real-time with near-IR. Flexural Strength (FS) and Modulus (E) were measured on 2 × 2 × 25 mm bars in 3-point bending after 24 h dry storage and 7-day storage in water at 37 °C. Antimicrobial properties and biofilm adhesion (fouling) were evaluated by bioluminescence (Luciferase Assay) and biofilm removal by water spray microjet impingement test, respectively. Cytotoxicity was assessed by MTT assay on dental pulp stem cells (DPSC). Data were analyzed with one-way ANOVA/Tukey's test (α = 0.05). DC was similar for all groups tested (∼70%). Both MAMs and C14-AM presented significantly lower RP. Under dry conditions, FS (110–120 MPa) and E (8–9 GPa) were similar for all groups. After water storage, all materials presented FS/E similar to the control, except for C14-AM (for FS) and C14-MAM (for E), which were lower. All C14 versions were strongly antibacterial, decreasing the titer counts of biofilm by more than two orders of magnitude in comparison to the control. C9 monomers did not present significant antibacterial nor antifouling properties. And biofilms had approximately equivalent adhesion on the C9 composites as on the control. Cytotoxicity did not show significant differences between the MA and AM versions and the control group. C14-QA monomers based on methacrylates and meth-acrylamides present strong antibacterial properties, and in general, similar conversion/mechanical properties compared to the methacrylate control. This work demonstrates the viability of methacrylamides and acrylamides as potential components in dental restorative materials with antimicrobial properties. The use of ester-free polymerizable functionalities has the potential of improving the degradation resistance of these materials long-term. The use of (meth)acrylamides did not interfere with the antimicrobial potential of quaternary ammonium-based materials. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Most dental resin composite restorations are replacements for failing restorations. Degradation of the restoration-tooth margins by cariogenic bacteria results in recurrent caries, a leading cause for restoration failure. Incorporating antimicrobial agents in dental adhesives could reduce interfacial bacterial count and reduce recurrent caries rates, inhibit interfacial degradation, and prolong restoration service life, while minimizing systemic exposure. Direct addition of antimicrobial compounds into restorative materials have limited release periods and could affect the integrity of the material. Attempts to incorporate antimicrobial within mesoporous silica nanoparticles showed theoretical promise due to their physical robustness and large available internal volume, yet yielded short-term burst release and limited therapeutic payload. We have developed novel broad-spectrum antimicrobial drug-silica particles co-assembled for long-term release and high payload incorporated into dental adhesives. The release of the drug, octenidine dihydrochloride, is modulated by the oral degradative environment and mathematically modeled to predict effective service life. Steady-state release kills cariogenic bacteria, preventing biofilm formation over the adhesive surface, with no toxicity. This novel material could extend dental restoration service life and may be applied to other long-term medical device-tissue interfaces for responsive drug release upon bacterial infection. Statement of Significance This study describes a novel dental adhesive that includes a broad-spectrum antimicrobial drug-silica co-assembled particles for long-term antimicrobial effect. The release of the drug, octenidine dihydrochloride, is modulated by the oral degradative environment and mathematically modeled to predict effective release throughout the service life of the restoration. Steady-state drug-release kills caries-forming bacteria, preventing biofilm formation over the adhesive surface, without toxicity. This novel material could extend dental restoration service life and may be applied to other long-term medical device-tissue interfaces for responsive drug release upon bacterial infection. Since recurrent cavities (caries) caused by bacteria are the major reason for dental filling failure, this development represents a significant contribution to the biomaterials field in methodology and material performance. [ABSTRACT FROM AUTHOR]

A series of water-soluble silver/reduced graphene oxide (Ag/rGO) composites were prepared with rGO as a carrier. The obtained composites were characterised by energy-dispersive X-ray spectrometer (EDS), TEM, X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analyses (TGA). TEM images demonstrated that well monodispersed silver nanoparticles (Ag NPs) precipitate on the rGO sheets. X-ray photoelectron spectroscopy showed that graphene oxide (GO) had been reduced to rGO in our hybrid. The antibacterial properties of Ag/rGO composites were investigated by bacteriostatic curve, and the experiments showed that the antibacterial properties of Ag/rGO antimicrobial materials were enhanced, which exhibited a superior antibacterial activity towards Escherichia coli (E. coli) because of the synergistic effect of rGO and Ag NPs. These results indicated that Ag/rGO composites attached to hierarchal hybrid supports can lead to compact and powerful antibacterial devices for chemical-free disinfection devices of the future. [ABSTRACT FROM AUTHOR]