Long-lasting Antibacterial Activity Research Articles

A Self-Transformed N-Chlorinated ε-Polylysine Coating Endows Titanium Implants with Programmed Integration of Robust Antibacterial and Pro-Osteogenic Abilities

Implant-associated infection and poor osseointegration are the main causes of orthopedic implantation failure. For a long-term successful implantation, simultaneously introducing prevention of infection and promotion of osteogenesis into implants is highly desired but remains a grand challenge. Inspired by the human immune mechanism of tissue repair under bacterial infection, we propose a self-transformed strategy for the modification of titanium with porous N-chlorinated ε-polylysine coating (Ti-PL-NCl) through pore-making, surface grafting and chlorination. The as-prepared Ti-PL-NCl exhibits an excellent antibacterial activity against S. aureus and E. coli in the presence of N-chloramine in the early stage, with an antibacterial rate as high as 95.8% and 99.4%, respectively. With the consumption of oxidative chlorine, the N─Cl groups of Ti-PL-NCl are transformed into N─H groups with moderate antibacterial yet strong pro-osteogenic abilities. The self-transformed N-chlorinated ε-polylysine coating enables Ti-PL-NCl to achieve long-lasting antibacterial activity as well as enhanced pro-osteogenesis, thus providing adaptive bioactivities for bone-implant integration. Rat implant-associated osteomyelitis model confirms that Ti-PL-NCl has excellent efficacy of infection prevention and osseointegration promotion. This work may provide a new paradigm of designing multifunctional implants to achieve long-term successful implantation.

Efficacy of vancomycin-loaded Mg-hydroxyapatite scaffolds in chronic osteomyelitis

In this study, we develop a novel magnesium (Mg)/hydroxyapatite (HA) scaffold loaded with vancomycin (VAN) to provide long-lasting antibacterial activity for bone defect repair in chronic osteomyelitis (CO) in children. Firstly, the VAN-Mg/HA nanoparticles were successfully synthesized, as evidenced by X-ray diffraction analysis. Additionally, the VAN-Mg/HA nanoparticles extended the half-life of VAN by nearly 5-fold. Moreover, our results revealed that the VAN-Mg/HA nanoparticles exhibited a significant antibacterial effect, which was further enhanced with an increase in the concentration of Mg/HA nanoparticles. We also found that the VAN-Mg/HA nanoparticles enhanced the viability and migration of BMSCs, indicating good biocompatibility and osteoconductivity. Furthermore, the VAN-Mg/HA nanoparticles demonstrated higher expression levels of osteogenesis-related genes, such as alkaline phosphatase, RUNX2, and osteocalcin, showing good osteogenic properties. In conclusion, the VAN-Mg/HA scaffolds show great potential for antibiosis and bone regeneration in children with CO.

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.

A highly stretchable, adhesive, and antibacterial hydrogel with chitosan and tobramycin as dynamic cross-linkers for treating the infected diabetic wound

Diabetic wounds pose a significant challenge due to their susceptibility to bacterial infection in a high-glucose environment, which impedes the wound healing process. To address this issue, there is a pressing need to develop suitable hydrogels that can promote the regeneration of diabetic wounds in clinical practice. In this study, we designed and fabricated a highly stretchable, adhesive, transparent, and antibacterial hydrogel through a one-pot radical polymerization of N-[Tris (hydroxymethyl) methyl] acrylamide (THMA) and acrylic acid (AA), and with chitosan and the antibiotic tobramycin as the dynamic physical crosslinkers. The copolymer contains a large number of carboxyl and hydroxyl groups, which can form an interpenetrating network structure with chitosan and tobramycin through multiple dynamic non-covalent bonds. This hydrogel exhibited over 1600 % elongation through an energy dissipation mechanism and strong adhesion to various surfaces without any chemical reaction. In vivo, studies conducted on a staphylococcus aureus-infected full-thickness diabetic skin wound model demonstrated that the hydrogel loaded with tobramycin as one of the crosslinkers had a long-lasting antibacterial activity and effectively accelerated wound healing. Therefore, the antibiotic-loaded adhesive hydrogel we proposed holds great promise as a treatment for bacteria-infected diabetic wounds.

Fabrication of controlled-release silver nanoparticle polylactic acid microneedles with long-lasting antibacterial activity using a micro-molding solvent-casting technique.

Most topical drug delivery techniques do not provide therapeutic concentrations for treatment of surgical site and other local infections and, therefore, require some kind of enhancement, such as physical methods like microneedles, the subject of the present investigation. Here, controlled-release long-lasting antibacterial polylactic acid (PLA) microneedles containing 1, 3, and 5% silver nanoparticles (AgNP) were prepared using micro-molding solvent-casting technique. Microneedles were characterized using optical microscopy, SEM, FTIR, XRD, and DSC. Also, mechanical strength, barrier disruption ability, insertion depth, in-vitro release kinetics, antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, and silver permeation through rat skin were studied. Microneedles showed good mechanical strength with no signs of failure at an optimum PLA concentration of 25%(w/v). FTIR revealed no chemical interaction between ingredients, and XRD confirmed presence of AgNP in microneedles. Microneedles penetrated the skin model at depth of up to 1143μm resulting 5-7 times increase in transepidermal water loss (TEWL). Release studies showed 2.2, 6.8, and 8.1µg silver release from the whole body (obeying Higuchi's release model) and 0.33, 0.45, and 0.78µg from the needles alone (obeying Fickian-cylindrical type release) for 1, 3, and 5% AgNP microneedles, respectively. Also, prolonged antibacterial activity (for 34days) was observed. Skin studies over 72h indicated that besides needles, silver is also released from the baseplate which had a marginal share in total silver permeation through the skin. In conclusion, a straightforward solvent-casting technique can be used to successfully prepare strong AgNP-containing PLA microneedles capable of long-lasting antibacterial activity.

Tannic Acid-Modified Silver Nanoparticles for Antibacterial and Anticancer Applications

In recent years, antibacterial nanosystems with loading and delivery capacity for anticancer agents have received increasingly widespread attention in the field of cancer treatment involving bacterial infection. Silver nanoparticles (AgNPs) are the most representative and widely used biocompatible metallic nanoparticles, which possess long-lasting and broad-spectrum antibacterial activity. However, conventional AgNPs are difficult to load and deliver anticancer agents directly because of their relatively inert surfaces. Herein, biocompatible silver nanoparticles (TA-AgNPs) were prepared via a simple approach in which tannic acid (TA) served as a “green” reducing and stabilizing agent. The resultant TA-AgNPs have low cytotoxicity against normal cells and exhibit significant antibacterial activity. The minimum inhibitory concentration (MIC) value of TA-AgNPs toward Escherichia coli was about 16 μg/mL, and the elimination rate of TA-AgNPs at a concentration of 0.5 mg/mL was above 99 and 93% at 6 h for E. coli and Staphylococcus aureus, respectively. TA-AgNPs have a good ability to load and deliver anticancer drug epirubicin hydrochloride (EPI). EPI can be adsorbed onto the surface of TA-AgNPs by strong electrostatic interaction between TA and EPI. The TA-AgNPs/EPI nanodrug displays a pH- and glutathione (GSH)-sensitive drug release performance through the protonation of phenolic hydroxyl groups in TA under an acid condition and the disassociation of TA molecules from the surface of AgNPs due to the ligand exchange reaction between GSH thiols and TA molecules. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay results showed an equal cytotoxicity effect against Hep G2 cells between free EPI and EPI-loaded TA-AgNPs. More importantly, the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay results indicated that the cytotoxicity of free EPI was significantly reduced in the presence of bacteria, but the resultant EPI-loaded TA-AgNPs could effectively prevent the influence of bacteria on the cytotoxicity of EPI. The animal tumor suppression and anti-infection model assay results indicated good tumor suppression and antibacterial properties of the TA-AgNPs/EPI nanodrug.

Thermosensitive nanocomposite hydrogel composed of PVPylated poly(D,L-alanine) and laponite as an injectable and bioactive biomaterial

Development of regenerative medicine requires multifunctional and bioactive materials/devices. Herein, we exploit a thermosensitive bioactive nanocomposite hydrogel composed of non-thermogelable poly(N-vinyl pyrrolidone)-b-poly(D,L-alanine) (PVP-PA) and laponite nanoclay, which displays a sol–gel transition with warming. The incorporation of PVP-PA and laponite in water first triggers self-assembly driven by hydrogen bonding and electrostatic interactions to form nanocomposite assemblies, and then turns into a physical hydrogel upon heating due to the assembly aggregation plus the partial conformation transformation of PA and PVP segments. Meanwhile, the gelation behavior of the composite system can be easily modulated by simply changing the concentration of either component. The presence of bioactive laponite and the improvement of mechanical and physiological stability enable the nanocomposite hydrogel to remain intact in vivo for over 90 days and exhibit good biological activity, which not only facilitates cell infiltration and vascularization inside the gel but also achieves rapid hemostasis within 10 s in rat bleeding models. Finally, thanks to the efficient complexation between PVP and poorly water-soluble iodine, an injectable iodophor hydrogel is conveniently obtained. The long-lasting antibacterial activity induced by continuously released iodine makes the multifunctional bioactive nanocomposite system promising for rapid wound hemostasis and accelerated wound/tissue repair while preventing infection.

Silver nanoparticles–decorated extracellular matrix graft: fabrication and tendon reconstruction performance

BackgroundThe reconstruction of tendons with large defects requires grafts with high mechanical strength and is often hindered by complications such as infection and adhesion. Hence, grafts combining the advantages of mechanical resilience and antibacterial/antiadhesion activity are highly sought after.MethodsThe silver nanoparticles (GA-Ag NPs) synthesized from gallic acid and silver nitrate were attached to a decellularized extracellular matrix (Decellularized Tendon crosslinking GA-AgNPs, DT-Ag). We examined the histological structure, mechanical property, morphology, Zeta potential, cytotoxicity, antibacterial properties, antioxidant and anti-inflammatory properties, and ability of the DT-Ag to treat tendon defects in animals.ResultsApproximately 108.57 ± 0.94 μg GA-Ag NPs loaded per 50 mg DT, the cross-linked part of GA-Ag NPs was 65.47 ± 0.57%, which provided DT-Ag with long-lasting antibacterial activity. Meanwhile, GA endowed DT-Ag with good antioxidant and anti-inflammatory activities. Additionally, The DT-Ag facilitated M2 macrophage polarization, and suppressed fibrin deposition by hindering fibroblast adhesion. Mormore, the main advantages of DT-Ag, namely its long-lasting antibacterial activity (tested using Escherichia coli and Staphylococcus aureus as models) and the ability to prevent tissue adhesion were confirmed in vivo.ConclusionThe fabricated multifunctional tendon graft was highly hydrophilic, biocompatible, and mechanically resilient, and concluded to be well suited for dealing with the main complications of surgical tendon reconstruction and has bright application prospects.Graphical

Zein-Functionalized MCM-41 Silica Nanoparticles with Enzyme-Responsive for Controlled Release in Antibacterial Activity

This research provided a novel enzyme-responsive antimicrobial carrier aiming at overcoming the volatile loss of active antibacterial components, by employing mesoporous silica nanoparticles (MCM-41) as the matrix of encapsulation and Zein as the molecular gate. Since Zein could be consumed by bacteria, Zein-functionalized MCM-41 acted as an enzyme-responsive gate and improved the controlled-release capacity. The results showed that the amount of capsaicin released from Zein-functionalized MCM-41 without bacteria was quite low compared with the essential oils liberated with bacteria. This validated that the delivery of capsaicin was hampered by Zein and the existence of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) promoted the release of encapsulated cargo. The release rate of capsaicin in Zein-functionalized MCM-41 climbed with the growth velocity of bacteria. These functions were realized in the form of controlled diffusion of essential oils encapsulated in MCM-41 by electrostatic interaction, and Zein was performed by both covalent bonding interaction and electrostatic interaction. Zein-functionalized MCM-41 was 2.4 times more effective in killing E. coli and 1.2 times more effective in inhibiting S. aureus than an equal amount of free capsaicin, and possessed a long-lasting antibacterial activity. The responsive antimicrobial material might be used as a promising preservative in the food industry for antimicrobial activity enhancement.

Interpenetrating Polymer Network Hydrogels Formed Using Antibiotics as a Dynamic Crosslinker for Treatment of Infected Wounds.

Antibacterial hydrogels, particularly antibiotic-loaded hydrogels, are promising wound dressing materials for treatment of bacteria-infected wound. However, it is challenging to achieve sustained release of antibiotics from hydrogels through physical encapsulation of the antibiotics. Herein, an interpenetrating polymer network P(AA-co-HEMA)Gen hydrogel is reported with double crosslinking formed by free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) and acrylic acid (AA), while using the antibiotic gentamicin (Gen) as the dynamic physical crosslinker. Gentamicin is incorporated into the hydrogel networks via electrostatic interaction between the carboxyl groups of poly(acrylic acid) and the amino groups of gentamicin, which leads to pH-responsive drug release and a significant increase in mechanical strength (i.e., elastic modulus, viscous modulus, and compressive modulus). More importantly, the hydrogels with optimal compositions demonstrate long-lasting antibacterial activity against both Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) over 28 d. The in vivo studies that are conducted in an S. aureus-infected full-thickness skin wound model demonstrate that thedouble crosslinking hydrogelsloadedwith gentamicin eliminate bacteria in the wounds more effectively and significantly accelerate wound healing as compared to 3M dressing and the control without any treatment. Taken together, this antibiotic-loaded interpenetrating polymer network hydrogel is potentially a promising wound dressing material for the treatment of bacteria-infected wound.

A two-phase and long-lasting multi-antibacterial coating enables titanium biomaterials to prevent implants-related infections.

In clinical work, the main challenges for titanium (Ti) implantation are bacterial infection and aseptic loosening, which severely affect the survival rate of implants. The first 4 weeks post-operation is the infection peak phase of implants. Inhibiting implant infection caused by bacteria adhesion and proliferation during the early phase as well as promoting subsequent osteointegration is essential for implant success. Herein, we constructed a quaternary ammonium carboxymethyl chitosan (QCMC), collagen (COL Ⅰ) and hydroxyapatite (HAP) multilayers coating on Ti substrates via a modified layer-by-layer (LBL) technique and polymerization of dopamine. The QCMC/COL/HAP coating exhibited a multi-antibacterial property with a two-phase function: (1) At the first 4 weeks post-operation, the covalently bonded QCMC could be slowly degraded and demonstrated both contact-killing and release-killing properties during the infection peak phase; (2) At the second phase, osteogenesis and osseointegration-promotion capabilities were enhanced by HAP under the effective control of infection. The multifilm coating was degraded for more than 45 days under the action of collagenase Ⅰ, and displayed good biocompatibility in vivo and in vitro. Most importantly, the coating exhibited a long-lasting antibacterial activity for more than 3 months, against the main pathogenic bacteria of peri-implant infections. Both in vitro studies and in vivo animal models revealed a desirable osteogenic differentiation capacity of Ti-CCH. Therefore, our study reports a two-phase, long-lasting multi-antibacterial coating on Ti-CCH and indicates potential applications of the modified LBL strategy in orthopaedic fields, which is enlightening for developing practical implant and scaffold materials.

Engineering DNA-Guided Hydroxyapatite Bulk Materials with High Stiffness and Outstanding Antimicrobial Ability for Dental Inlay Applications.

Programmable base pair interactions at the nanoscale make DNA an attractive scaffold for forming hydroxyapatite (HAP) nanostructures. However, engineering macroscale HAP mineralization guided by DNA molecules remains challenging. To overcome this issue, a facile strategy is developed for the fabrication of ultrastiff DNA-HAP bulk composites. The electrostatic complexation of DNA and a surfactant with a quaternary ammonium salt group enables the formation of long-range ordered scaffolds using electrospinning. The growth of 1D and 2D HAP minerals is thus realized by this DNA template at a macroscale. Remarkably, the as-prepared DNA-HAP composites exhibit an ultrahigh Young's modulus of ≈25GPa, which is comparable to natural HAP and superior to most artificial mineralized composites. Furthermore, anew type of dental inlay with outstanding antibacterial properties is developed using the stiff DNA-HAP. The encapsulated quaternary ammonium group within the dense HAP endows the composite with long-lasting and local antibacterial activity. Therefore, this new type of super-stiff biomaterial holds great potential for oral prosthetic applications.

Citric acid crosslinked sphingan WL gum hydrogel films supported ciprofloxacin for potential wound dressing application

Sphingan WL gum (WL), a kind of exopolysaccharides, is produced by Sphingomonas sp. WG. In this study, citric acid (CA) crosslinked WL hydrogel films were firstly developed for potential wound dressing application. ATR-FTIR and TG results suggested the occurrence of esterification crosslinking. SEM analysis showed that this aided covalent crosslinking could prevent their porous structures from collapsing when swelling. Due to the deprotonation of carboxyl groups, the water absorption capacity of WL-CA hydrogel films increased with the increase of pH (maximum swelling ratio = 38 g/g). The covalent crosslinked swollen WL-CA hydrogels exhibited certain hydrolytic stability, high porosity (>60%), moderate tissue adhesion, and good rheological property (G′ > G″, G′ up to 2 kPa). WL-CA-CIP hydrogel films loaded with antibiotic ciprofloxacin (CIP) showed sustained drug release properties, long-lasting antibacterial activity, and superior biocompatibility. All the results indicated that WL-based hydrogels were potential candidates for wound dressing applications.

Chitosan and polyhexamethylene guanidine dual-functionalized cotton gauze as a versatile bandage for the management of chronic wounds

Development of versatile medical dressing with good immediate and long-lasting antibacterial, hygroscopic and moisturizing abilities is of great significance for management of chronic wounds. Cotton gauze (CG) can protect wounds and promote scabbing, but can cause wound dehydration and loss of biologically active substances, thereby greatly delays wound healing. Herein, a bi-functional CG dressing (CPCG) was developed by chemically grafting polyhexamethylene guanidine (PHMG) and physically adsorbing chitosan (CS) onto the CG surface. Due to the powerful microbicidal activity of PHMG, CPCG exhibited excellent immediate and long-lasting antibacterial activity against gram-positive and gram-negative bacteria. Moreover, the abundant hydroxyl and amino groups in CS endowed CPCG with good biocompatibility, moisture absorption, moisturizing and cell scratch healing performances. Importantly, CPCG can be easily fabricated into a bandage to conveniently manage infected full-skin wounds. Together, this study suggests that CPCG is a versatile wound dressing, having enormous application potential for management chronic wounds.

Silver loaded biodegradable carboxymethyl chitin films with long-lasting antibacterial activity for infected wound healing.

Bacteria-related infections are one of the main causes of human skin infections, which are associated with the delay of wound healing and secondary complications. In this work, a series of novel biodegradable films based on thermosensitive carboxymethyl chitin were prepared without using any crosslinkers. All the carboxymethyl chitin films had good flexibility, high transparency, and appropriate water absorption capacity, and could provide a moist environment for wound healing. The silver ions (Ag+) were incorporated on the LTCF-5 film, which had the best mechanical strength (56.39 MPa in the dry state and 0.66 MPa in the wet state) among the carboxymethyl chitin films and was higher than those of the reported biodegradable dressings and commercially available dressings. Compared with the commercial hydrofiber dressing with silver (AQUACEL®), the composite film could provide slow and sustained release of Ag+ with good strength and biodegradability, and displayed excellent long-lasting antibacterial activity in vitro against both S. aureus and E. coli without obvious cytotoxicity, which still possessed good antibacterial activity with almost 100% bacteriostatic rates after soaking in phosphate buffered saline for 7 days. More importantly, the Ag+ loaded carboxymethyl chitin film could promote infected cutaneous wound healing in a S. aureus infected full-thickness cutaneous defect in vivo model because of its long-lasting antibacterial activity, good biocompatibility, exudate absorption and ability to maintain a moist environment. Thus Ag+ loaded carboxymethyl chitin films are excellent candidates for infected wound healing.

Development of the mussel-inspired pH-responsive hydrogel based on Bletilla striata polysaccharide with enhanced adhesiveness and antioxidant properties

Recently, smart hydrogels have attracted much attention for their abilities to respond to subtle changes in external and internal stimuli. Also, natural polysaccharide-based biomaterials are more appealing for their biocompatibility and biodegradability. However, limitations owing to their complex compositions and mechanisms, cumbersome synthetic routes, and single function call for a simple and effective strategy to develop novel multifunctional smart hydrogels. Herein, this developed work was achieved based on Bletilla striata polysaccharide (BSP), a kind of natural glucomannan with diverse bioactivities and biocompatibility, we fabricated a low-cost multifunctional hydrogel by oxidizing the catechol groups of carboxymethylated BSP(CBSP)-dopamine(DA) conjugate with adhesion, antioxidant, and pH-responsive properties. In this hydrogel system, CBSP as the backbone material, was negatively charged and conferred the hydrogel with pH sensitivity. The presence of catechol groups greatly enhanced the tissue adhesion and antioxidant capacities of the hydrogel. Meanwhile, the highly porous structure of hydrogel allowed berberine to be encapsulated and released to exhibit excellent and long-lasting antibacterial activity. In summary, the adhesion, antioxidant, pH-sensitive, and antibacterial multifunctional hydrogel showed massive potential in the biomedical field.

Star polymer-mediated in-situ synthesis of silver-incorporated reverse osmosis membranes with excellent and durable biofouling resistance

Biofouling mitigation for water purification membranes is critically important for the efficient separation process. Most anti-biofouling thin-film nanocomposite (TFN) membranes have been incorporated with biocidal nanomaterials via ex-situ hybridization, often leading to performance deterioration and ineffective nanomaterial incorporation. Here, we present a new in-situ hybridization strategy for the fabrication of silver-incorporated TFN (CD-Ag-TFN) reverse osmosis (RO) membranes exhibiting excellent anti-biofouling and separation performance by utilizing an amine-functionalized star polymer. CD-Ag-TFN membranes were formed by adding a Ag precursor (AgNO3) to an aqueous solution containing poly(acryloyl hydrazide)-branched star polymers (CD-PAHs) prior to interfacial polymerization with trimesoyl chloride (TMC). Numerous amine groups in CD-PAH strongly adsorbed Ag+ ions via complexation, which were subsequently converted to Ag or AgCl nanoparticles, while simultaneously forming a polyamide (PA) selective layer via the reaction with TMC, consequently creating a uniform PA-Ag hybrid network. Due to its greater hydrophilicity and high crosslinking density, the optimized CD-Ag-TFN membrane exhibited RO performance, which is better than that of the CD-PAH-assembled control (CD-TFC) and comparable to than that of recently reported other lab-made RO membranes. Importantly, the robust and effective incorporation of Ag endowed the CD-Ag-TFN membrane with remarkably long-lasting anti-bacterial activity and greater anti-biofouling performance than control CD-TFC.

Asymmetric barrier membranes based on polysaccharide micro-nanocomposite hydrogel: Synthesis, characterization, and their antibacterial and osteogenic activities

Guided tissue regeneration (GTR) strategies enable periodontal tissue regeneration, generally by providing barrier membranes. However, currently available membranes have limited osteoconductive and antibacterial potential. To address these challenges, we fabricated a new asymmetric barrier membrane. Agarose hydrogel functions as the main body of the barrier membrane. Hollow carbonated hydroxyapatite (CHA) prepared by hydrothermal method, was sedimented in agarose to exhibit an asymmetrical structure. And ε-poly-lysine (ε-PLL) was chosen as an antimicrobial agent to equip the membrane with long-lasting antibacterial activity. With the increased dose of CHA addition, the barrier membrane shows better biocompatibility, and higher mechanical properties. We demonstrated the osteoconductivity and antibacterial properties of the membrane in vitro and in vivo. In summary, our findings suggest that the barrier membrane has good osteoconductive and antibacterial properties, indicating its potential for periodontal tissue engineering.

Development of active packaging films based on poly (butylene adipate-co-terephthalate) and silver–montmorillonite for shelf life extension of sea bream

This paper is a continuation of our previous study focusing on the development of active food packaging films and presents the results of their potential application in the sea bream storage. Intended for fish packaging, active nanocomposite films based on poly (butylene adipate-co-terephthalate) and silver–montmorillonite (PBAT/Ag-MMT) with 2, 3 and 5 wt. % of Ag-MMT were successfully prepared and characterized by several techniques which confirmed the formation of exfoliated nanocomposite structures with a random dispersion of spherically shaped Ag nanoparticles on the whole of the polymer matrix. PBAT/Ag-MMT films exhibited a sharp reduction in their water and oxygen permeabilities. The kinetic study of the silver ions migration confirmed that the release was mainly ensured by diffusion. Due to this controlled release, these packaging films displayed a long-lasting antibacterial activity. Furthermore, the results of their use as sea bream packaging films confirmed their great potential for maintaining the freshness and quality of the fish and extending its shelf life for a period of 15 days.

The preparation, characterization and antibacterial properties of chitosan/pectin silver nanoparticle films

Edible film production from natural biodegradable polymers that will not cause environmental waste problems has been increasing in recent years. Antibacterial materials can be added to these films to increase the shelf life and quality of products. In this work, chitosan-based and chitosan/pectin-based silver nanoparticle films which has eco-friendly and antibacterial properties were synthesized. The morphological test of the prepared films was performed by scanning electron microscope and transmission electron microscope. The presence of silver element was detected by energy-dispersive X-ray. Thermal analysis was tested with thermogravimetric analysis and differential scanning calorimeter analyzer. The crystallinity (%) of films was determined with X-ray diffraction analyzer. The presence of pectin increased the thermal stability and crystallinity%. The mechanical tests were examined with Zwick universal testing machine and the content of pectin improved the mechanical properties of film. The antibacterial test was done toward Gram-negative bacteria (Escherichia coli). Chitosan/pectin-based films compared with chitosan-based film displayed long-lasting antibacterial activity against E.coli.