Inherent Antibacterial Properties Research Articles

Multifunctional and novelty green composite film containing sodium alginate, chitosan, rice husk and curcumin

Foodborne diseases are a global public health issue, with their causes often originating from lapses in food production or transportation leading to food contamination. Therefore, food packaging plays a crucial role in preserving the safety and quality of food. In pursuit of sustainable development, this study aims to utilize agricultural waste-derived functional mesoporous silica nanoparticles in combination with biodegradable molecules to create food packaging films. Through recycling and the use of environmentally friendly green films, the goal is to achieve sustainability and the objectives of green chemistry. The study anticipates the production of biodegradable films and the testing of their antibacterial capabilities, antioxidant properties, biocompatibility, and film stress coefficients. This research will provide robust support for advancing green packaging technology to address the challenges of global food safety and environmental sustainability.The experiment is divided into two parts. The first part involves the synthesis of multifunctional mesoporous silica nanoparticles with antibacterial properties derived from rice husk (Rice husk mesoporous silica nanoparticles, rMSN) as nano-fillers. These nanoparticles are surface modified with a biodegradable polymer, chitosan (Chi), that interacts with the material. Natural extract curcumin (Cur), known for its antioxidant capabilities, is loaded into the pores, and the material's inherent antibacterial properties are utilized. The second part involves blending the material with the natural polymer sodium alginate (SA) to form a film (rMSN-Chi@Cur/Alg film). The film's thickness, stress strength, antibacterial, and antioxidant capabilities are tested to ensure the material possesses antibacterial and antioxidant properties.

Unveiling the Potential of Protein-Based Sustainable Antibacterial Materials.

The surge in bacterial growth and the escalating resistance against a multitude of antibiotic drugs have burgeoned into an alarming global threat, necessitating urgent and innovative interventions. In response to this peril, scientists have embarked on the development of advanced biocompatible antibacterial materials, aiming to counteract not only bacterial infections but also the pervasive issue of food spoilage resulting from microbial proliferation. Protein-based biopolymers and their meticulously engineered composites are at the forefront of this endeavor. Their potential in combating this severe global concern presents an approach that intersects the domains of biomedicine and environmental science. The present review article delves into the intricate extraction processes employed to derive various proteins from their natural sources, unraveling the complex biochemical pathways that underpin their antibacterial properties. Expanding on the foundational knowledge, the review also provides a comprehensive synthesis of functionalized proteins modified to enhance their antibacterial efficacy, unveiling a realm of possibilities for tailoring solutions to specific biomedical and environmental applications. The present review navigates through their antibacterial applications; from wound dressings to packaging materials with inherent antibacterial properties, the potential applications underscore the versatility and adaptability of these materials. Moreover, this comprehensive review serves as a valuable roadmap, guiding future research endeavors in reshaping the landscape of natural antibacterial materials on a global scale.

Antibiofilm and antibacterial activities of green synthesized ZnO nanoparticles against Erwinia amylovora and Pseudomonas syringae pv. Syringae: in vitro and in silico investigations

Today, many infections in plants are related to biofilm-developing bacteria. These infections can result in severe agricultural losses. Thus, this study aims to investigate the synergistic antibiofilm activity of Thymus vulgaris extract on the inherent antibacterial properties of ZnO nanoparticles against Erwinia amylovora and Pseudomonas syringae pv. syringae. Additionally, to gain insight into the molecular mechanisms of phytocompounds’ antibacterial activity, the molecular interactions of T. vulgaris phytochemicals with the TolC protein and TonB-dependent siderophore receptor were investigated through in-silico studies. Green-synthesized ZnO NPs (ZnO@GS) and chemically synthesized ZnO (ZnO@CHS) were evaluated using XRD and SEM techniques, showing a crystalline structure for both powders with average sizes of 50, and 40 nm, respectively. According to FT-IR and EDS spectroscopy, ZnO@GS was covered with thyme extract. Based on the in vitro results, all samples of ZnO NPs exhibited considerable antibacterial activity against both bacteria. At the same time, thyme aqueous extract alone proved considerably less effective at all tested concentrations. Compared to ZnO@CHS and thyme extract, the antibacterial efficacy of ZnO@GS against E. amylovora (MIC = 512 μg/mL) and P. syringae pv. syringae (MIC = 256 μg/mL) was significantly improved upon surface covering with thyme phytocompounds. Moreover, their antibiofilm properties were enhanced by almost 20 % compared to ZnO@CHS. In addition, molecular docking investigations showed that most of the phytocompounds could form stable interactions with the TonB-dependent siderophore receptor (P. syringae) plug domain and the TolC (E. amylovora) external channel. In vitro and in silico studies demonstrate that using the green approach for synthesizing ZnO NPs via thyme extract can notably boost its antibacterial and antibiofilm effects on the tested phytopathogenic bacteria.

Extraction of Bio Oil from Jordanian Biomass Resources via Pyrolysis and its Antibacterial Effect

This study explores the potential of pyrolytic oil extracted from Jordanian biomass resources as an antibacterial agent. Pyrolysis, a transformative thermal decomposition process, offers a promising avenue for converting biomass into valuable products. Pyrolytic oil, derived from biomass via pyrolysis, presents a complex composition and inherent antibacterial properties, making it a candidate for addressing antibiotic resistance and promoting sustainable solutions. Five biomass feed stocks were subjected to pyrolysis and their product distributions were analyzed. Pyrolytic oil yields were investigated and antibacterial activities against four bacterial strains were evaluated using disc diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Results indicate varying levels of antibacterial activity among the biomass extracts, highlighting their potential as eco-friendly antibacterial agents.

Fortification of cotton fabrics with dithiocarbamate-metal complexes to prepare durable antimicrobial fabrics

In this study, a simple and practical method is reported to fortify cotton fabrics with dithiocarbamate (DTC-Ct), dithiocarbamate-Cu (Cu-Ct) and dithiocarbamate-Ni (Ni-Ct) complexes via impregnation process to prepare durable antimicrobial fabrics. FTIR analysis indicates the presence of characteristic peaks corresponding to cellulose functional groups in the fortified fabrics. SEM micrographs illustrate the transition from a closed-packed, smooth surface in untreated cotton to a rough texture enveloped with metal complexes in fortified fabrics. EDX images confirm successful impregnation, with prominent peaks due to C and O in the untreated cotton, while additional signals of S, Cu, and Ni were observed in the fortified samples. TEM images revealed irregular, spherical nanoparticles within fortified cotton, compared with the rough surface of untreated fabrics. The average size of the treated cotton fabric fell within the range of 2.20–7.32, 3.83–28.50, and 2.70–7.32 nm for DTC-Ct, Cu-Ct and Ni-Ct, respectively. Untreated cotton fabric exhibits no inherent antibacterial properties, whereas fortified cotton fabrics demonstrate enhanced antibacterial efficacy against strains including Salmonella typhi, Enterobacter aerogenes, Shigella dysenteriae, and Klebsiella pneumonia, with Ni-Ct-fortified cotton proving most effective. Furthermore, the durability of additive adhesion to cotton fabrics was evaluated through washing tests, revealing robust adherence even after multiple cycles, with sustained antimicrobial inhibition observed for up to five wash cycles.

Tannic Acid-Enabled Antioxidant and Stretchable MXene/Silk Strain Sensors for Diving Training Healthcare.

MXene-based conductive hydrogels hold significant promise as epidermal sensors, yet their susceptibility to oxidation represents a formidable limitation. This study addresses this challenge by incorporating MXene into a tannic acid (TA) cross-linked silk fibroin matrix. The resulting conductive hydrogel (denoted as e-dive) exhibits favorable characteristics such as adjustable mechanical properties, self-healing capabilities (both mechanically and electrically), and strong underwater adhesion. The existence of a percolation network of MXene within the nanocomposites guarantees good electrical conductivity. Importantly, the surface interaction of MXene nanosheets with the hydrophobic moiety from TA substantially reduced moisture and oxygen interactions with MXene, thereby effectively mitigating MXene oxidation within hydrogel matrices. This preservation of the electrical characteristics ensures prolonged functional stability. Furthermore, the e-dive demonstrates inherent antibacterial properties, making it suitable for use in underwater environments where bacterial contamination is a concern. The utilization of this advanced e-dive system extends to the correction of diving postures and the facilitation of underwater healthcare and security alerts. Our study presents a robust methodology for enhancing the stability of MXene-based conductive hydrogel electronics, thereby expanding their scope of potential applications.

Photo-crosslinking injectable Photothermal antibacterial hydrogel based on quaternary ammonium grafted chitosan and hyaluronic acid for infected wound healing

Antibacterial hydrogels not only provide a better environment for skin wounds to avoid infection but also accelerate wound healing. Herein, chitosan modified by a quaternary ammonium salt (CQ), and hyaluronic acid grafted with methacrylate (HM) were designed and synthesized to prepare an injectable photo-crosslinking hydrogel for wound dressing with inherent antibacterial and photothermal properties. CQ and HM exhibited excellent biocompatibility, improved water retention, and antibacterial activity, illustrating vast potential as an antibacterial material in various applications. MXene, a type of 2D nanomaterial, has been widely researched due to its photothermal properties. The CQ and HM polymer precursor could be mixed with Mxene and then crosslinked with 395 nm UV radiation under mild conditions to form a 3D network structure CQ-HM/MXene hydrogel. This hydrogel displayed an appropriate swelling ratio, elastic modulus, photothermal property and excellent biocompatibility. The injectable property of the hydrogel allowed it to easily cover the wound. In vitro and in vivo studies showed that the injectable hydrogel had low cytotoxicity and excellent antibacterial properties, which could help promote wound healing. In summary, this novel CQ-HA/MXene hydrogel has the potential for application in skin wound healing due to inherent antibacterial activity and photothermal effect.

Synergistic antibacterial effects of selenium-doped gold nanosheets with notable near infrared-II photothermal conversion against multidrug-resistant bacteria

Non-metallic nanoparticles are increasingly acknowledged for their broad-spectrum antibacterial properties, which often face limitations due to structural instability and potential biotoxicity. To address these challenges, integrating non-metallic nanoparticles with plasmonic metal nanostructures offers a promising solution. This fusion not only enhances structural stability but also reduces the required dosage. The synergistic coupling of the inherent antibacterial properties of non-metallic nanoparticles with the plasmonic absorption and photothermal conversion capabilities of metal nanostructures significantly amplifies antibacterial efficacy. In this study, we validate this concept by presenting the successful synthesis of selenium-doped gold nanosheets (AuSe NSs) that demonstrate robust absorption in the second near-infrared (NIR-II) window and exhibit efficient photothermal conversion, followed by testing their antibacterial activity. Notably, Au NSs were synthesized with high shape purity, followed by the introduction of SeO2 and ascorbic acid to facilitate Se doping. The resulting products displayed a uniform distribution of both Au and Se elements, while maintaining the NIR-II absorbance characteristic of Au nanosheets unaffected by the Se doping as evidenced by both experimental and FDTD simulation results. Subsequent assessments of the AuSe NSs demonstrated their potent synergistic antibacterial effects against multidrug-resistant bacteria at minimal inhibitory concentrations (MICs), which suggests that lower dosages can be employed and benefit minimizing potential side effects and optimizing treatment efficiency. Our findings indicate a synergistic boost between the photothermal attributes originating from Au's NIR absorption and Se's inherent antibacterial properties—an aspect minimally explored in prior research and offering a novel solution to tackling antibiotic-resistant bacterial strains.

Preparation of a bifunctional precursor with antibacterial and flame retardant properties and its application to cotton fabrics

Cotton fabric is a cellulose-based material with complex capillary spaces, which enhance breathability and softness. However, these capillary spaces can promote bacterial growth with moisture during storage and daily use. Additionally, cotton fibers are highly flammable, posing a fire hazard to wearer. The lack of inherent antibacterial and flame retardant properties in cotton fabric limits its applications. In this paper, the triazole compound containing Schiff base (NABTA) was synthesized from 3-bromopropene, p-hydroxybenzaldehyde and 3-amino-1,2,4-triazole, followed by an addition reaction between Schiff base activity and 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO) to synthesize an antibacterial and flame retardant precursor (NABTA-DOPO). The structure of NABTA and NABTA-DOPO was characterized by FTIR and NMR. NABTA and NABTA-DOPO were applied to cotton fabrics to investigate and compare their antibacterial properties and thermal stability. The results showed that all the cotton fabrics treated with NABTA and NABTA-DOPO had favorable antibacterial effects. The introduction of DOPO had no significant effect on the antibacterial effect and mechanism of the fabrics. However, it otherwise improved the burning stability of treated cotton fabrics. The antibacterial activity of 10 g/L NABTA-DOPO treated cotton fabrics after chlorination against E. coli and S. aureus was over 99.99 %. The vertical burning test results showed that cotton fabrics treated with a concentration of 50 g/L NABTA-DOPO had improved flame retardant properties with a damaged length of 5.9 cm. In addition, the storage, washability, UV stability and antibacterial reproducibility experiments demonstrated the excellent durability and reproducibility of the N-halamine structure of chlorinated cotton fabrics. This study enhances cotton fabric by synthesizing and applying NABTA and NABTA-DOPO, resulting in improved multifunctionalities, including antibacterial properties, flame retardancy, UV resistance, and wettability.

Covalent Grafting of Tanfloc on Titania Nanotube Arrays: An Approach to Mitigate Bacterial Adhesion and Improve the Antibacterial Efficacy of Titanium Implants

AbstractImplanted medical devices often face the challenge of infections, which can compromise their successful integration and use. To address this issue, this study demonstrates the covalent grafting of a tannin‐based antimicrobial biopolymer tanfloc (TAN) onto the titania nanotube arrays (TiNTs) surface to enhance antibacterial properties. Due to its polyphenolic and ionic structural configuration, tanfloc possesses unique properties that enable it to interact with and disrupt bacterial cell walls and membranes. Combining the topographical effect of TiNTs with the inherent antibacterial properties of tanfloc, this approach aims to mitigate bacterial threats on medical implants effectively. The successful attachment of tanfloc on TiNTs is confirmed through X‐ray photoelectron spectroscopy (XPS) and Fourier‐transform infrared spectroscopy (FT‐IR). The antibacterial and antibiofilm efficacy of the tanfloc‐functionalized TiNTs is evaluated against Staphylococcus aureus (Gram‐positive) and Pseudomonas aeruginosa (Gram‐negative) bacteria. The findings suggest that the covalent conjugation of tanfloc onto TiNTs is a promising approach to improve the infection resistance of titanium‐based medical implants, with potential applications in orthopedic, dental, and other biomedical device areas.

Antibacterial and Anticorrosive Hydrogel Coating Based on Complementary Functions of Sodium Alginate and g-C3N4.

Graphitic carbon nitride (g-C3N4, CN) has emerged as a promising photocatalytic material due to its inherent stability, antibacterial properties, and eco-friendliness. However, its tendency to aggregate and limited dispersion hinder its efficacy in practical antibacterial applications. To address these limitations, this study focuses on developing a composite hydrogel coating, in which sodium alginate (SA) molecules interact electrostatically and through hydrogen bonding to anchor CN, thereby significantly improving its dispersion. The optimal CN loading of 35% results in a hydrogel with a tensile strength of 120 MPa and an antibacterial rate of 99.87% within 6 h. The enhanced mechanical properties are attributed to hydrogen bonding between the -NH2 groups of CN and the -OH groups of SA, while the -OH groups of SA facilitate the attraction of photogenerated holes from CN, promoting carrier transfer and separation, thereby strengthening the antibacterial action. Moreover, the hydrogel coating exhibits excellent antibacterial and corrosion resistance capabilities against Pseudomonas aeruginosa on 316L stainless steel (316L SS), laying the foundation for advanced antimicrobial and anticorrosion hydrogel systems.

An Injectable Thermosensitive Hydrogel with Antibacterial and Antioxidation Properties for Accelerating Wound Healing.

As a new type of wound dressing, hydrogels have attracted more and more attention. However, traditional hydrogel wound dressings lack inherent antibacterial properties and are difficult to match irregular wounds, which leads to an easy wound bacterial infection. To solve the problems associated with traditional hydrogels, in this research, a thermosensitive hydrogel (PFLD) for wound dressings was developed based on Poloxamer 407 (PF127), lysine (Lys), and 3,4-dihydroxyphenylacetic acid (DOPAC). Rheological tests indicated that the PFLD hydrogel possesses injectability, adaptability to deformation, and sufficient mechanical strength for wound dressing applications. In addition, it could in situ gel at 33 °C, which indicated that the hydrogel could undergo sol-to-gel transition under body temperature. Upon using it in wound treatment, it could adapt to irregular wounds to achieve full coverage of the wound and promote the rapid hemostasis of wound bleeding. Due to the presence of DOPAC in the hydrogel, it exhibited excellent antibacterial and antioxidant properties on the wounds. The skin defect model showed that the wound shrinkage was the fastest after PFLD hydrogel treatment. On day 14, the wound shrinkage rates were 81.68 and 99.77% for the control and PFLD hydrogel groups, respectively. Therefore, the PFLD hydrogel has a broad application prospect as a dressing for the treatment of irregular wounds.

The Significance of Munjayadi Dravya in Mritasanrakshana Paddhati: A Scientific Exploration of Life-Preserving Elixirs

A well-preserved body is required for the dissection of a human cadaver in order to examine the entire body, which requires both theoretical and practical understanding of human anatomy. Modern science has developed a number of methods for preserving dead bodies, however Acharya Sushruta only cites one in Ayurveda. This method is known as the "Jalnimajjan Paddhati" of Mritsanrakshana. Numerous directions are given in this paddhati, and one of them mentions some of the munjayadi dravyas from which one dravya is employed to wrap the body. Attending paper is about studying the role of these dravyas in delaying the body decaying process. Each and every Munjayadi dravya contains tannin. Tannin has inherent anti-inflammatory, antiviral, antibacterial, and antifungal properties. Due to above properties tannins containing plants helps in delaying the process of decaying of dead body.

Tannic acid coating gauze immobilized with thrombin with ultra-high coagulation activity and antimicrobial property for uncontrollable hemorrhage

Rapid and safe hemostasis is crucial for the survival of bleeding patients in prehospital care. It is urgent to develop high performance hemostatic material to control the massive hemorrhage in the military field and accidental trauma. In this work, an efficient protein hemostat of thrombin was immobilized onto commercial gauze, which was mediated by self-polymerization and anchoring of tannic acid (TA). Through TA treatment, the efficient immobilization of thrombin was achieved, preserving both the biological activity of thrombin and the physical properties of the dressing, including absorbency, breathability, and mechanical performance. Moreover, in the presence of TA coating and thrombin, Gau@TA/Thr could obviously shortened clotting time and enriched blood components such as plasma proteins, platelets, and red blood cells, thereby exhibiting an enhanced in vitro coagulation effect. In SD rat liver volume defect and artery transection hemorrhage models, Gau@TA/Thr still had outstanding hemostatic performance. Besides, the Gau@TA/Thr gauze had inherent antibacterial property and demonstrated excellent biocompatibility. All results suggested that Gau@TA/Thr would be a potential candidate for treating uncontrollable hemorrhage in prehospital care.

Utilizing nutrient type compounds as anti-bacterial compounds: arginine and cysteine inhibit Salmonella survival in egg white.

Because of growing levels of antibiotic resistance, new methods to combat bacteria are needed. We hypothesized that because bacteria evolved to survive in specific environments, the addition of compounds, including nutrient type compounds, to an environment, might result in a modification of that environment that will disrupt bacterial growth or in maladaptive bacterial behavior, i.e., gene expression. As a proof of concept, we focused on the egg white environment and the pathogen Salmonella. Despite egg white's antibacterial nature, Salmonella is able to survive and grow in egg white, and this ability of Salmonella leads to infection of chicks and humans. Here, the 20L-amino-acids were screened for their ability to affect the growth of Salmonella in egg white. L-arginine and L-cysteine were found to reduce growth in egg white in physiologically relevant concentrations. To determine the mechanism behind L-arginine inhibition TnSeq was utilized. TnSeq identified many Salmonella genes required for survival in egg white including genes required for iron import, biotin synthesis, stress responses, cell integrity, and DNA repair. However, a comparison of Salmonella in egg white with and without L-arginine identified only a few differences in the frequency of transposon insertions, including the possible contribution of perturbations in the cell envelope to the inhibition mechanism. Finally, both D-arginine and D-cysteine were found to inhibit Salmonella in egg white. This implied that the effect of arginine and cysteine in egg white is chemical rather than biological, likely on the egg white environment or on the bacterial outer membrane. To conclude, these results show that this approach of addition of compounds, including nutrient type compounds, to an environment can be used to limit bacterial growth. Importantly, these compounds have no inherent anti-bacterial properties, are used as nutrients by animals and bacteria, and only become anti-bacterial in a specific environmental context. Future research screening for the effects of compounds in relevant environments might uncover new ways to reduce pathogen levels in the poultry industry and beyond.

New Zein Protein Composites with High Performance in Phosphate Removal, Intrinsic Antibacterial, and Drug Delivery Capabilities.

Herein, poly(N-(4-aminophenyl)methacrylamide)-carbon nano-onions [abbreviated as PAPMA-CNOs (f-CNOs)] integrated gallic acid cross-linked zein composite fibers (ZG/f-CNOs) were developed for the removal/recovery of phosphate from wastewater along with controlled drug delivery and intrinsic antibacterial characteristics. The composite fibers were produced by Forcespinning followed by a heat-pressure technique. The obtained ZG/f-CNOs composite fibers presented several favorable characteristics of nanoadsorbents and drug carriers. The composite fibers exhibited excellent adsorption capabilities for phosphate ions. The adsorption assessment demonstrated that composite fibers process highly selective sequestration of phosphate ions from polluted water, even in the presence of competing anions. The ZG/f-CNOs composite fibers presented a maximum phosphate adsorption capacity (qmax) of 2500 mg/g at pH 7.0. This represents the most efficient phosphate adsorption system among all of the reported nanocomposites to date. The isotherm studies and adsorption kinetics of the adsorbent showed that the adsorption experiments followed the pseudo-second-order and Langmuir isotherm model (R2 = 0.9999). After 13 adsorption/desorption cycles, the adsorbent could still maintain its adsorption efficiency of 96-98% at pH 7.0 while maintaining stability under thermal and chemical conditions. The results mark significant progress in the design of composite fibers for removing phosphates from wastewater, potentially aiding in alleviating eutrophication effects. Owing to the f-CNOs incorporation, ZG/f-CNOs composite fibers exhibited controlled drug delivery. An antibiotic azithromycin drug-encapsulated composite fibers presented a pH-mediated drug release in a controlled manner over 18 days. Furthermore, the composite fibers displayed excellent antibacterial efficiency against Gram-positive and Gram-negative bacteria without causing resistance. In addition, zein composite fibers showed augmented mechanical properties due to the presence of f-CNOs within the zein matrix. Nonetheless, the robust zein composite fibers with inherent stimuli-responsive drug delivery, antibacterial properties, and phosphate adsorption properties can be considered promising multifunctional composites for biomedical applications and environmental remediation.

Nano-Based Approaches in Surface Modifications of Dental Implants: A Literature Review.

Rehabilitation of fully or partially edentulous patients with dental implants represents one of the most frequently used surgical procedures. The work of Branemark, who observed that a piece of titanium embedded in rabbit bone became firmly attached and difficult to remove, introduced the concept of osseointegration and revolutionized modern dentistry. Since then, an ever-growing need for improved implant materials towards enhanced material-tissue integration has emerged. There is a strong belief that nanoscale materials will produce a superior generation of implants with high efficiency, low cost, and high volume. The aim of this review is to explore the contribution of nanomaterials in implantology. A variety of nanomaterials have been proposed as potential candidates for implant surface customization. They can have inherent antibacterial properties, provide enhanced conditions for osseointegration, or act as reservoirs for biomolecules and drugs. Titania nanotubes alone or in combination with biological agents or drugs are used for enhanced tissue integration in dental implants. Regarding immunomodulation and in order to avoid implant rejection, titania nanotubes, graphene, and biopolymers have successfully been utilized, sometimes loaded with anti-inflammatory agents and extracellular vesicles. Peri-implantitis prevention can be achieved through the inherent antibacterial properties of metal nanoparticles and chitosan or hybrid coatings bearing antibiotic substances. For improved corrosion resistance various materials have been explored. However, even though these modifications have shown promising results, future research is necessary to assess their clinical behavior in humans and proceed to widespread commercialization.

Flowable resin-based composites modified with chlorhexidine-loaded mesoporous silica nanoparticles induce superior antibiofilm properties

Clinical failure of dental resin-composite restorations is mainly due to bacterial-mediated secondary caries formation. Therefore, the development of a flowable resin-composite material having inherent antibacterial properties is crucial to enhance the durability of dental restorations. Herein, dental flowable resin-composite material was modified with chlorhexidine-loaded mesoporous silica nanoparticles (CHX-MSN) to induce in situ antibacterial properties against S. mutans. Mesoporous silica nanoparticles loaded with chlorhexidine (CHX-MSN) were formulated and characterized for drug-loading/encapsulation efficiency, morphology by electron microscopy, and infrared spectral analysis. CHX-MSN were incorporated into the flowable composite material at different concentrations of 1, 5, and 10% (w/w) and examined at two time points (baseline and 3 months in artificial saliva). The CHX-MSN modified composites exhibited an initial CHX release burst followed by a steady release up to 30 days. The antimicrobial efficacy of the modified composites was evaluated by crystal violet assay, MTT assay, and confocal laser scanning microscopy. In addition to measuring the degree of conversion and cytotoxicity, the mechanical properties were characterized by surface microhardness and flexural strength. The modified composites demonstrated a significant increase in antimicrobial properties compared to the unmodified control (p < 0.05) which is dependent on the concentration of the CHX-MSN nanoparticles. In addition, the modified composites possessed acceptable biocompatibility without adversely affecting mechanical properties and degree of conversion up to 5% addition of CHX-MSN nanoparticles. This study introduced a protocol to develop resin-based flowable dental composite material having superior antibacterial property against cariogenic biofilms aiming for enhancing clinical longevity of dental restorations.Graphical

A novel titanium alloy for load-bearing biomedical implants: Evaluating the antibacterial and biocompatibility of Ti536 produced via electron beam powder bed fusion additive manufacturing process

Additive manufacturing (AM) of Ti-based biomedical implants is a pivotal research topic because of its ability to produce implants with complicated geometries. Despite desirable mechanical properties and biocompatibility of Ti alloys, one major drawback is their lack of inherent antibacterial properties, increasing the risk of postoperative infections. Hence, this research focuses on the Ti536 (Ti5Al3V6Cu) alloy, developed through Electron Beam Powder Bed Fusion (EB-PBF), exploring bio-corrosion, antibacterial features, and cell biocompatibility. The microstructural characterization revealed grain refinement and the formation of Ti2Cu precipitates with different morphologies and sizes in the Ti matrix. Electrochemical tests showed that Cu content minimally influenced the corrosion current density, while it slightly affected the stability, defect density, and chemical composition of the passive film. According to the findings, the Ti536 alloy demonstrated enhanced antibacterial properties without compromising its cell biocompatibility and corrosion behavior, thanks to Ti2Cu precipitates. This can be attributed to both the release of Cu ions and the Ti2Cu precipitates. The current study suggests that the EB-PBF fabricated Ti536 sample is well-suited for use in load-bearing applications within the medical industry. This research also offers an alloy design roadmap for novel biomedical Ti-based alloys with superior biological performance using AM methods.

Malleable, Ultrastrong Antibacterial Thermosets Enabled by Guanidine Urea Structure.

Dynamic covalent polymers (DCPs) that strike a balance between high performance and rapid reconfiguration have been a challenging task. For this purpose, a solution is proposed in the form of a new dynamic covalent supramolecular motif-guanidine urea structure (GUAs). GUAs contain complex and diverse chemical structures as well as unique bonding characteristics, allowing guanidine urea supramolecular polymers to demonstrate advanced physical properties. Noncovalent interaction aggregates (NIAs) have been confirmed to form in GUA-DCPs through multistage H-bonding and π-π stacking, resulting in an extremely high Young's modulus of 14 GPa, suggesting remarkable mechanical strength. Additionally, guanamine urea linkages in GUAs, a new type of dynamic covalent bond, provide resins with excellent malleability and reprocessability. Guanamine urea metathesis is validated using small molecule model compounds, and the temperature dependent infrared and rheological behavior of GUA-DCPs following the dissociative exchange mechanism. Moreover, the inherent photodynamic antibacterial properties are extensively verified by antibacterial experiments. Even after undergoing three reprocessing cycles, the antibacterial rate of GUA-DCPs remains above 99% after 24 h, highlighting their long-lasting antibacterial effectiveness. GUA-DCPs with dynamic nature, tuneable composition, and unique combination of properties make them promising candidates for various technological advancements.