Long-lasting Antibacterial Properties Research Articles

Multi-functional Gleditsia sinensis galactomannan-based hydrogel with highly stretchable, adhesive, and antibacterial properties as wound dressing for accelerating wound healing

Design and development of a multifunctional wound dressing with self-healing, adhesive, and antibacterial properties to attain optimal wound closure efficiency are highly desirable in clinical applications. Nevertheless, conventional hydrogels face significant barriers in their mechanical strength, adhesive performance, and antibacterial properties. Herein, a tough hydrogel based on aldehyde-grafted galactomannan was synthesized through radical copolymerization and Schiff base reaction, incorporating hyaluronic acid, acrylamide, and the zwitterionic monomer to create a multi-crosslinked structure. The multiple crosslink structure pattern consisting of multiple hydrogen bonding, ionic interactions, reversible Schiff bases bonds, and molecular chain entanglement endowed this hydrogel with multiple functionalities, including high tensile strength (25 kPa), tensile strain (2200 %), toughness (391.59 kJ/m3), and Young's modulus (9.77 kPa). The presence of catechol groups and zwitterionic groups endow hydrogels with outstanding adhesion strength (42.21 kPa), which satisfied the adhesive demand for the ample motion of specific areas. The zwitterionic monomer provided long-lasting antibacterial properties and promoted migration and growth of negatively charged cells, capable of establishing efficient antibacterial barriers and serving as wound dressing. The in vivo and vitro experiments manifested that the optimized hydrogel demonstrated an inconspicuous inflammatory response, facilitating rapid healing of full-thickness skin wound in rat models. Therefore, this work provides a promising strategy and an ideal candidate for wound healing dressings in treating infected skin wounds.

AAO-ZnO nanocomposite coatings on aluminum alloy surface with high bonding strength and long-lasting antibacterial properties

A robust and durable antibacterial nanocomposite coating consisting of anodic aluminum oxide (AAO) and zinc oxide (ZnO) was synthesized by sol–gel deposition of ZnO onto AAO nanotubes. This unique coating features a dual-layer structure: an intermediate AAO + ZnO layer (∼3.9 μm) and a ZnO layer (∼0.8 μm). Nanosized ZnO particles, ranging from 20 to 40 nm, nucleate and grow along the walls of AAO nanotubes within this structure. AAO nanotubes, functioning as “nanocontainers”, offer appropriate sites for the deposition of ZnO particles. The mechanically interlocked AAO + ZnO interlayer enhances the adhesion between the external layer and the inner substrate. Meanwhile, this interlayer facilitates the sustained release of both Zn2+ ions and reactive oxygen species (ROS), effectively impeding bacterial proliferation. Ultraviolet antibacterial tests reveal that the AAO + ZnO interlayer maintains exceptional antibacterial efficacy, even after removing the outermost ZnO layer. The antibacterial rates of the AAO + ZnO interlayer against the above two typical bacteria (E. coli and S. aureus) after 1 h could still reach 91.4 % and 89.0 %, respectively. Specifically, AAO nanopores serve as an inert container for ZnO nanoparticles with consistently release of Zn2+ ions and reactive oxygen species (ROS), thereby ensuring the long-term antibacterial effectiveness of the AAO-ZnO coating. This research also demonstrates the significant potential of AAO-ZnO nanocomposite coating on aluminum alloys for durable antibacterial applications.

Double-drying 3D lamellar-structured aerogel membrane for efficient oil-water separation and long-lasting antibacterial activity

Conventional oil-water separation membranes are difficult to establish a trade-off between membrane flux and separation efficiency, and often result in serious secondary contamination due to their fouling issue and non-degradability. Herein, a double drying strategy was introduced through a combination of oven-drying and freeze-drying to create a super-wettable and eco-friendly oil-water separating aerogel membrane (TMAdf). Due to the regular nacre-like structures developed in the drying process and the pores formed by freeze-drying, TMAdf aerogel membrane finally develops regularly arranged porous structures. In addition, the aerogel membrane possesses excellent underwater superoleophobicity with a contact angle above 168° and antifouling properties. TMAdf aerogel membrane can effectively separate different kinds of oil-water mixtures and highly emulsified oil-water dispersions under gravity alone, achieving exceptionally high flux (3693 L·m−2·h−1) and efficiency (99 %), while being recyclable. The aerogel membrane also displays stability and universality, making it effective in removing oil droplets from water in corrosive environments such as acids, salts and alkalis. Furthermore, TMAdf aerogel membrane shows long-lasting antibacterial properties (photothermal sterilization up to 6 times) and biodegradability (completely degraded after 50 days in soil). This study presents new ideas and insights for the fabrication of multifunctional membranes for oil-water separation.

Enhanced antibacterial and osteogenic properties of titanium by sputtering a nanostructured fluoride-doped tantalum oxide coating

Infections and poor osseointegration are the main challenges for titanium implants in clinical practice. Herein, we proposed fabricating a novel fluoride-doped tantalum oxide (F-TaOx) coating on titanium by one-step reactive sputtering deposition to endow implants with superior antibacterial and osteogenic ability. By altering the fluorine and oxygen loading amount, the coating’s physicochemical properties, corrosion resistance, antibacterial and osteogenic activities are tuned simultaneously. All coatings exhibit nano-morphology, superhydrophilicity and improved surface hardness. Despite containing fluoride, the F-TaOx coating produced with fluorine and oxygen dual-deposition still shows enhanced corrosion resistance due to the protection of existing metal oxidizes. The antibacterial test reveals that the F-TaOx coating exhibits long-lasting and superior antibacterial properties. The microenvironment acidification by F-, the excessive ROS generation and the disruption of ATP by F-, TiF3 and Ta2O5, and the repulsive force by superhydrophilic surface synergistically result in bacterial death. The cell experiments indicate that the F-TaOx coating shows good cytocompatibility, promote cell spread and osteogenic differentiation by enhancing ALP activities and ECM mineralization. This work provides a promising strategy for the surface functionalization of metallic implants to produce dual anti-infection and osteogenesis effects for orthopedic and dental applications.

Green modifications for rendering cotton fabric with antibacterial, anti-mite, and mosquito-repellent functions using single natural eugenol

Cotton fabrics are widely used in everyday life; however, increasing their versatility through green modifications remains a challenge. The current mainstream approach merely physically attaches the additives onto the fibers, resulting in low binding affinity. In this study, novel cotton fabrics (Cotton-Si-EU) with long-lasting antibacterial, anti-mite, and mosquito-repellent properties were facilely fabricated in a green procedure. In contrast to conventional coating and physical addition methods, the eugenol graft modification ensured the safety, environmental friendliness and long-lasting functionality of the Cotton-Si-EU. In addition, Cotton-Si-EU fabrics retained the softness, comfort, breathability, and moisture absorption originating from the cotton fabric. Cotton-Si-EU also showed over 99.99% antibacterial, 73% anti-mite, and 75% mosquito repellent rates, simultaneously destroying microorganisms and insects through oxidative stress, inhibiting enzyme activity, affecting cell structure, and other mechanisms. More importantly, after 50 washing cycles, the fabrics still exhibited durable antibacterial properties higher than the AAA requirements, indicating high functional longevity. In addition, good cytocompatibility, hemocompatibility, and negligible skin irritation demonstrated excellent biological safety. Therefore, this study is of great significance in providing a reference for modifying cotton fabrics using an infinite number of natural products after screening, which will broaden the application scope and improve the safety level of functional cotton fabrics.

Hierarchical antibiotic delivery system based on calcium phosphate cement/montmorillonite-gentamicin sulfate with drug release pathways

Antibiotic-loaded calcium phosphate cement (CPC) has emerged as a promising biomaterial for drug delivery in orthopedics. However, there are problems such as the burst release of antibiotics, low cumulative release ratio, inappropriate release cycle, inferior mechanical strength, and poor anti-collapse properties. In this research, montmorillonite-gentamicin (MMT-GS) was fabricated by solution intercalation method and served as the drug release pathways in CPC to avoid burst release of GS, achieving promoted cumulative release ratios and a release cycle matched the time of inflammatory response. The results indicated that the highest cumulative release ratio and release concentration of GS in CPC/MMT-GS was 94.1 ± 2.8 % and 1183.05 μg/mL, and the release cycle was up to 504 h. In addition, the hierarchical GS delivery system was divided into three stages, and the kinetics followed the Korsmeyer-Peppas model, the zero-order model, and the diffusion-dissolution model, respectively. Meanwhile, the compressive strength of CPC/MMT-GS was up to 51.33 ± 3.62 MPa. Antibacterial results demonstrated that CPC/MMT-GS exhibited excellent in vitro long-lasting antibacterial properties to E. coli and S. aureus. Furthermore, CPC/MMT-GS promoted osteoblast proliferation and exhibited excellent in vivo histocompatibility. Therefore, CPC/MMT-GS has favorable application prospects in the treatment of bone defects with bacterial infections and inflammatory reactions.

Enhanced mechanical and long-lasting antibacterial properties of starch/PBAT blown films via designing of reactive micro-crosslinked starch

A functional starch (TPS-E) was designed and constructed by incorporating epoxy soybean oil (ESO) and an antibacterial agent polyhexamethylene guanidine hydrochloride (PHMG), then the film was prepared by reaction extrusion and blow molding using TPS-E and poly(butylene adipate-co-terephthalate) (PBAT). The micro-crosslinking structure, forming through ring-opening reaction between the epoxy active site of TPS-E and the end group of PBAT, improved the compatibility of starch/PBAT blend and reduce the dispersed starch phase size, leading to significantly increase the tensile strength. Compared to starch/PBAT films, the tensile strength of TPS-E/PBAT in the longitudinal direction increase by 112% with the same starch content of 30%. Furthermore, these TPS-E/PBAT films demonstrated long-lasting antibacterial performance with a 98% inhibition ratio even after 10 cycles, without any observed leaching of the antibacterial agent, highlighting the high coupling efficiency of PHMG. TPS-E with the degradable ESO also promotes the degradation of PBAT. Thus, an important method of synergistic improving the mechanical, degradable and antibacterial properties of blown films through the design of reactive micro-crosslinked starch structures was established.

Photothermal controlled antibacterial Ta4C3Tx-AgNPs/nanocellulose bioplastic food packaging

Uncontrolled antibacterial, insufficient barrier and low strength are the bottlenecks of food packaging applications. Herein, Ta4C3Tx nanosheet as a template was used to prepare Ta4C3Tx immobilized silver nanoparticles (Ta4C3Tx-AgNPs), which was compounded with nanocellulose to obtain high-strength and high barrier controllable bactericidal nanocellulose-based bioplastic packaging (CTa-Ag). The results indicated that due to the hydrogen bonding between nanocellulose and Ta4C3Tx, the bridging effect of QCS (quaternized chitosan) and the filling of Ta4C3Tx-AgNPs, the CTa-Ag had tightly stacked microstructure, which endowed them with excellent mechanical properties (4.0 GPa), ultra-low oxygen permeability (0.009 cm3/m2·d·atm) and stable photothermal conversion efficiency. Importantly, the packaging exhibits the ability to control the release of antibacterial active ingredients. Moreover, the synergistic effects of controllable release of nano active factors, photothermal and photocatalysis in CTa-Ag gave it long-lasting antibacterial properties. This study brings new insights into the design and manufacture of multifunctional, controllable and long-lasting antibacterial bioplastic food packaging.

Mechanical, bioactive, and long-lasting antibacterial properties of a Ti scaffold with gradient pores releasing iodine ions

The ideal bone implant would effectively prevent aseptic as well as septic loosening by minimizing stress shielding, maximizing bone ingrowth, and preventing implant-associated infections. Here, a novel gradient-pore-size titanium scaffold was designed and manufactured to address these requirements. The scaffold features a larger pore size (900 μm) on the top surface, gradually decreasing to small sizes (600 μm to 300 μm) towards the center, creating a gradient structure. To enhance its functionality, the additively manufactured scaffolds were biofunctionalized using simple chemical and heat treatments so as to incorporate calcium and iodine ions throughout the surface. This unique combination of varying pore sizes with a biofunctional surface provides highly desirable mechanical properties, bioactivity, and notably, long-lasting antibacterial activity. The target mechanical aspects, including low elastic modulus, high compression, compression-shear, and fatigue strength, were effectively achieved. Furthermore, the biofunctional surface exhibits remarkable in vitro bioactivity and potent antibacterial activity, even under conditions specifically altered to be favorable for bacterial growth. More importantly, the integration of small pores alongside larger ones ensures a sustained high release of iodine, resulting in antimicrobial activity that persisted for over three months, with full eradication of the bacteria. Taken together, this gradient structure exhibits obvious superiority in combining most of the desired properties, making it an ideal candidate for orthopedic and dental implant applications.

Fabrication of a superhydrophobic cotton fabric with efficient antibacterial properties and asymmetric wettability via synergistic effect of quaternized chitosan/TiO2/Ag

A superhydrophobic cotton fabric with unidirectional moisture transfer ability, antibacterial, and oil-water separation capabilities was fabricated by combining a simple coating method and oxygen plasma etching. Polydimethylsiloxane (PDMS) was employed to impart low surface energy to the cotton fabric, thereby endowing it with hydrophobic characteristics. The synthesized quaternized chitosan/TiO2/Ag (CTA) compound was subsequently applied onto the cotton fabric surface to introduce a desirable level of surface roughness, thus enhancing its hydrophobic properties and conferring excellent antibacterial efficacy. The cotton was subsequently treated by oxygen plasma to trigger asymmetrical wetting on both sides. The experimental findings reveal that the optimally treated cotton fabric exhibits hydrophobic properties on the bottom surface, with a water contact angle (WCA) reaching 162.8°, while the upper surface displays hydrophilic behavior, establishing a wetting gradient along the thickness direction. Notably, even under the influence of reverse gravity, water droplets are capable of transferring from the back to the top surface within 2 s, while preventing reverse penetration of liquid. Moreover, the synthesized compound CTA endows the cotton fabric with efficient and long-lasting antibacterial properties through two modes (contact and release sterilization modes) and three sterilization mechanisms (electrostatic interaction, plasma surface resonance effect, and reactive oxygen species). Remarkably, within a time frame of only 1 h, the modified cotton fabric is able to achieve a kill rate exceeding 99% against Escherichia coli and Staphylococcus aureus. Moreover, the aforementioned properties demonstrate outstanding durability against repeated washing, continuous abrasion, exposure to strong acid/base, and ultraviolet radiation. Additionally, this modified cotton fabric exhibits remarkable efficiency in terms of oil-water separation, effectively separating both light and heavy oil from water. It is worth noting that the preparation process is cost-effective, environmentally friendly, and free from fluorine.

Protein-based coating strategy for preparing durable sunlight-driven rechargeable antibacterial, super hydrophilic, and UV-resistant textiles

With the improvement of the hygiene awareness and pathogen prevention awareness of patients and medical staff, textiles with efficient and long-lasting pathogen inactivation effects are urgently needed. Photodynamic therapy (PDT) has rapidly developed into a new type of antibacterial technology due to its high antibacterial activity and has received widespread attention. However, the commonly used photosensitizers are mostly inorganic nanomaterials, which have poor adhesion to textiles and are not environmentally or human friendly. Here, we report a strategy of preparation of a sunlight-driven rechargeable antibacterial textiles based on natural antibacterial agents, which can work in light and dark conditions. The prepared BD-PTL@wool has long-lasting antibacterial properties, can rapidly produce ROS, and can store sterilization activity under light irradiation, ensuring all-day bacterial killing (>99.95 % under light irradiation and >99.80 % under dark conditions after light irradiation). BD-PTL@wool has excellent reusability, and the antibacterial rate can still above 95 % after repeated use for 5 times. In addition, BD-PTL@wool has excellent hydrophilic, UV resistance, biocompatibility and can withstand 50 washing cycles. The successful application of this strategy in textile preparation broadens the research idea for exploring the application of green photosensitive antibacterial materials in textile field.

Antifouling Zwitterionic Nanofibrous Wound Dressing for Long-Lasting Antibacterial Photodynamic Therapy.

Nanofibrous mats as a wound dressing have received great attention in recent year. The development of biocompatible dressings with antibiofouling capability and long-lasting antibacterial properties is important but challenging. Antibacterial photodynamic therapy (aPDT) effectively eliminates pathogens via a photodynamic process that can circumvent the emergence of antibiotic-resistant pathogens. In this study, we integrated the zwitterionic materials (2-methacryloyloxyethyl phosphorylcholine (MPC) moiety) and aPDT photosensitizer, methylene blue (MB), to fabricate a long-lasting antibacterial nanofibrous mat using electrospinning technology. The prepared nanofibers possessed an appropriate water absorption and retention ability, superior cytocompatibility, and antibiofouling ability against both proteins and L929 cell adhesion. MB-loaded nanofibrous mats have exhibited superior aPDT against Gram-positive Staphylococcus aureus compared to Gram-negative Escherichia coli under moderate irradiation (100 W m-2) due to the presence of an extra outer membrane of Gram-negative bacteria serving as a protective barrier. In vitro release study demonstrated that the nanofibrous mat had a long-lasting drug release profile, which can efficiently suppress bacterial growth via aPDT. The antibacterial ability of the MB-loaded nanofibrous mat was commensurate or slightly inferior to antibiotics such as tetracycline and kanamycin, suggesting that it has the potential to be used as an antibiotic alternative. Overall, this zwitterionic nanofibrous mat with long-lasting aPDT function and nonadherent properties has potential as a promising antibacterial wound dressing.

TEMPO-oxidized nanocellulose immobilized AgNPs modified chitosan composite film with durable antibacterial and preservative properties for fruits and vegetables package

Film preservative packaging is one of common techniques to solve rot problem of fruits and vegetables in transit, storage and sale process. But traditional petroleum-based films have no long-lasting antibacterial properties and they are difficult to biodegrade. Herein, TEMPO-oxidized nanocellulose (TCNF) was used as green reducer and stabilizer to synthesize and immobilize silver nanoparticles (AgNPs) in one-pot method. Next the TCNF immobilized AgNPs was combined with chitosan to form antibacterial preservative composite film (CS/TCNF@AgNPs). The results show that CS/TCNF@AgNPs exhibited satisfied preservative effects for cherry tomatoes and strawberries. Notably, the composite film showed excellent antibacterial properties against E. coli and S. aureus and the accumulated release amount of AgNPs was only about 2.05% after 264 h. Furthermore, the composite film degraded almost completely in soil within 25 days. The cytotoxicity assay also exhibited favorable biocompatibility. Therefore, the composite film has potential application as a packaging material for fruit and vegetable antibacterial preservation.

Comparative Analysis of Performance of Water-Based Coatings Prepared by Two Kinds of Anti-Bacterial Microcapsules and Nano-Silver Solution on the Surface of Andoung Wood

A nano-silver solution, urea-formaldehyde resin-coated nano-silver solution microcapsules (AgNPS@UF), and melamine-formaldehyde resin-coated chitosan-modified nano-silver solution microcapsules (CS-AgNPS@MF) were added into the coatings at different contents for comparative tests to explore an anti-bacterial agent with the best anti-bacterial properties in the water-based coatings on Andoung wood (Monopetalanthus spp.). As the content of anti-bacterial agents increased, AgNPS@UF had the best anti-bacterial property towards Staphylococcus aureus and Escherichia coli, with anti-bacterial rates of 79.0% and 82.1%, respectively. The optical and mechanical properties of the coating quickly worsened as the content of anti-bacterial agents increased. The anti-bacterial coatings with AgNPS@UF have the minimum chromatic aberration change of 6.5. The anti-bacterial coating with 5% content of AgNPS@UF decreased the aging rate. This coating had good optical properties, and its liquid-resistant level is 2. When the 5% content of AgNPS@UF was added, after high-temperature accelerated aging and ultraviolet (UV) aging, the anti-bacterial rates of the coating with AgNPS@UF decreased toward Escherichia coli from 82.1% to 62.2% and decreased toward Staphylococcus aureus from 79.3% to 61.1%, respectively. This shows that the coating had a long-lasting anti-bacterial property. The anti-bacterial property of the coating after high-temperature accelerated aging was superior to that after the UV aging. The incorporation of AgNPS@UF in water-based coatings protects people from the risks of Escherichia coli and Staphylococcus aureus more effectively with long-lasting property. The research results provide a reference for the preparation of anti-bacterial water-based coatings on the surface of the Andoung wood.

Amyloid-like protein bridged nano-materials and fabrics for preparing rapid and long lasting antibacterial, UV-resistant and personal thermal management textiles

Textiles with efficient and long-lasting antibacterial properties have attracted significant attention. However, a single antibacterial model is insufficient to with variable environments and achieve higher antibacterial activity. In this study, lysozyme was used as assistant and stabilizer, and the efficient peeling and functional modification of molybdenum disulfide nanosheets were realized by ultrasonic. Additionally, lysozyme in the presence of reducing agents to form amyloid-like phase-transited lysozyme (PTL) and self-assembling on the wool fabric. Finally, the AgNPs are reduced in situ by PTL and anchored onto the fabric. It has been demonstrated that Ag-MoS2/PTL@wool generates ROS under light irradiation, rapidly converts photothermal heat into generate hyperthermia, and promotes the release of Ag+. The aforementioned “four-in-one” approach resulted in bactericidal rates of 99.996 % (4.4 log, P < 0.0005) and 99.998 % (4.7 log, P < 0.0005) for S.aureus and E.coli, respectively. Even after 50 washing cycles, the inactivation rates remained at 99.813 % and 99.792 % for E.coli and S.aureus, respectively. In the absence of sunlight, AgNPs and PTL continue to provide continuous antibacterial activity. This work emphasizes the importance of amyloid protein in the synthesis and application of high-performance nanomaterials and provides a new direction for the safe and effective application of multiple synergistic antibacterial modes for microbial inactivation.

The Efficacy of Various Novel Copper-Based Antibacterial Solutions on E. Coli

The COVID-19 pandemic has accelerated the need for long-lasting sanitation solutions in households, businesses, and schools. Current disinfectants, like Lysol, kill bacteria and other microbes only at initial application and are ineffective under aqueous conditions. Copper (II) ions and Lactic Acid are highly regarded for their synergetic, long-lasting antibacterial properties. Although L-pyroglutamic acid holds similar properties, little research has examined its efficacy with copper metal. The purpose of this experiment is to find a novel, clinically safe, antibacterial solution for instantaneous microbial inhibition and continued inhibition over extended periods of time in aqueous solutions. Two antibacterial solutions utilizing Copper (II) Sulfate (10 ppm) were developed with 1% Lactic Acid (Solution A) and 1% L-Pyroglutamic Acid (Solution B). The extinction rate of Escherichia coli K12 bacteria for each solution and Lysol was recorded. The concentration of E. coli was observed via spectrophotometry at 3-time intervals: Initial Introduction (28 Minutes), Short Term (2 Hours) and Long Term (72 hours). At initial introduction, there was no significant difference between solutions (p&gt;0.05) ranging from 22 to 28% E. coli loss from the original sample. Significant growth inhibition (p

Montmorillonite and AgNPs modified corn stalk-based filling material with fire retardancy and antibacterial activity

At present, the reuse of corn stalk (CS) or other biomass stalk generally requires crushing or dissolution, which leads to waste of energy and use of toxic chemicals. In this work, porous CS was directly utilized without any pretreatment as furniture and building materials by loading silver nanoparticles (AgNPs) and montmorillonite (MMT), which endowed excellent flame retardant and antibacterial properties. Firstly, CS was delignified (DLCS) to expose more porous structures. Then, DLCS was used to in situ reduce and immobilize AgNPs, and MMT particles was further loaded into holes of DLCS to prepare antibacterial and flame-retardant CS (DLCS/MMT/AgNPs). Due to the oxygen barrier layer formed by MMT in the combustion process, the time DLCS/MMT/AgNPs started combustion delayed to 5 s while that of CS was 1 s. The combustion residue of DLCS/MMT/AgNPs retained after burning under nitrogen and air atmosphere at 800 °C were 65.8% and 61%, respectively, and basically maintained its original morphology. Furthermore, AgNPs endowed DLCS/MMT/AgNPs with the inhibition zone of 3.5 mm and 2.0 mm for E. coli and S. aureus, respectively, as well as long-lasting antibacterial property for at least 7 days. This work laid a theoretical foundation for agricultural waste CS to realize the high-value utilization in an economical and environmentally friendly way.

Preparation, characterization, and antibacterial effect of bio-based modified starch films

There are several problems with common starch films, including strong water absorption and poor mechanical properties. To create a better starch film, octenyl succinate cassava starch ester (OSCS) was first blended with chitosan and nano ZnO to prepare an OSCS/CS/ZnO film. Then, the film was supplemented with different concentrations of ε-PL as a bacteriostatic agent to prepare a film that would resist bacterial invasion. The mechanical properties, barrier properties, optical properties, and color of the modified starch antibacterial films were investigated, and finally the antibacterial properties and cytotoxicity were tested. The results demonstrated that the modified starch antibacterial film had good mechanical properties, improved surface hydrophobicity, and had a UV-blocking effect. The modified starch antibacterial film with ε-PL of 8% had stable and long-lasting antibacterial properties, stable release, and good cytocompatibility. An active packaging material was successfully prepared using ε-PL and had a strong preservative effect on food.

Castor oil-based, robust, non-leaching and durable antibacterial waterborne polyurethane/polyhexamethylene guanidine composites prepared via an electrostatic self-assembly strategy

Antibacterial materials with durable antibacterial properties and high mechanical strength from renewable resources recently have attracted extensive attention. In this study, a facile and environmentally friendly electrostatic self-assembly strategy was adopted to prepare a series of castor oil-based waterborne polyurethane/polyhexamethylene guanidine (WPU/PHMG) composites. The relationship between performance (antibacterial properties, mechanical properties, etc.) and the chemical structures of these resulting composite films has been systematically investigated. The results showed that the antibacterial rate of these antibacterial composite films against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was more than 99.9%. Interestingly, the obtained composite films still demonstrated long-lasting antibacterial properties after 42 days of immersion in water and six cycles of antibacterial testing due to the synergistic effect of electrostatic interaction and intermolecular hydrogen bonds. In addition, the tensile strength of the obtained composite films was significantly improved up to 30 MPa, 2 times higher than the original polyurethane films, and the toughness was high up to 70 MJ/m3, which could easily pull up to 19,000 times their own weight. Furthermore, the water absorption of the obtained composite films was greatly reduced from 56.4% to 6.6% due to their high crosslinking densities and intermolecular interaction. The technique reported in this study provides a facile and simple strategy for development of high mechanical properties and durable antibacterial properties of bio-based polymer composites, which would find promising applications in medical devices, product packaging, and so on.

Calcium alginate/silk fibroin peptide/Bletilla striata polysaccharide blended microspheres loaded with tannic acid for rapid wound healing

Biodegradable natural polymers are receiving increasing attention as potential candidates for wound dressing. In the present study, composite microspheres (mCSB) based on calcium alginate (CA), silk fibroin peptide (SP), and Bletilla striata polysaccharide (BSP) were prepared by the reverse emulsion method. The excellent swelling properties of microspheres enable them to rapidly promote thrombosis. Microspheres can increase the platelet aggregation index to 1.5 and the aggregation rate of red blood cells to as high as 80 %. Furthermore, tannic acid (TA)-loaded microspheres demonstrate a slow-release effect on TA; this allows the microspheres to exhibit good long-lasting antibacterial properties. Due to the synergistic effects of SP and TA, the cell senescence was delayed, with a 126.69 % survival rate of fibroblasts after 3 days of incubation. In addition, TA led to a rapid reduction in inflammation levels, with a wound closure rate of >92.80 % within 7 days. The multifunctional TA-loaded mCSB has great application potential for rapid wound healing and the treatment of wound hemostasis.