A hydrogel adhesive fabricated from poly(ethylene glycol) diacrylate and poly(allylamine hydrochloride) with fast and spontaneous degradability and anti-bacterial property

ZnO Nanoparticle-Infused Vaterite Coatings: A Novel Approach for Antimicrobial Titanium Implant Surfaces

Loss of implant function is a common complication in orthopaedic and dental surgery. Among the primary causes of implant failure are peri-implant infections which often result in implant removal. This study demonstrates the development of a new antimicrobial titanium coating with ZnO nanoparticles of various sizes and morphologies immobilised in poly(allylamine hydrochloride) and alginate multilayers, combined with epitaxially grown vaterite crystals. The coated samples were characterised with various methods (FTIR, XRD, SEM) and surface properties were evaluated via water contact angle and surface charge measurements. Zinc ion release was quantified using ICP-MS. The antimicrobial efficacy of the coatings was tested against Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans while the biocompatibility was tested with preosteoblast cells (MC3T3-E1). Results demonstrated the successful preparation of a calcium carbonate/ZnO composite coating with epitaxially grown vaterite on titanium surfaces. The Zn ions released from ZnO nanoparticles dramatically influenced the morphology of vaterite where a new flower-like morphology was observed. The coated titanium surfaces exhibited robust antimicrobial activity, achieving over 90% microbial viability reduction for Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. Importantly, the released Zn2+ concentrations remained below the cytotoxicity limit for MC3T3-E1 cells, showing potential for safe and effective implant applications.

Poly(Allylamine Hydrochloride) and ZnO Nanohybrid Coating for the Development of Hydrophobic, Antibacterial, and Biocompatible Textiles

In healthcare facilities, infections caused by Staphylococcus aureus (S. aureus) from textile materials are a cause for concern, and nanomaterials are one of the solutions; however, their impact on safety and biocompatibility with the human body must not be neglected. This study aimed to develop a novel multilayer coating with poly(allylamine hydrochloride) (PAH) and immobilized ZnO nanoparticles (ZnO NPs) to make efficient antibacterial and biocompatible cotton, polyester, and nylon textiles. For this purpose, the coated textiles were characterized with profilometry, contact angles, and electrokinetic analyzer measurements. The ZnO NPs on the textiles were analyzed by scanning electron microscopy and inductively coupled plasma mass spectrometry. The antibacterial tests were conducted with S. aureus and biocompatibility with immortalized human keratinocyte cells. The results demonstrated successful PAH/ZnO coating formation on the textiles, demonstrating weak hydrophobic properties. Furthermore, PAH multilayers caused complete ZnO NP immobilization on the coated textiles. All coated textiles showed strong growth inhibition (2-3-log reduction) in planktonic and adhered S. aureus cells. The bacterial viability was reduced by more than 99%. Cotton, due to its better ZnO NP adherence, demonstrated a slightly higher antibacterial performance than polyester and nylon. The coating procedure enables the binding of ZnO NPs in an amount (<30 µg cm-2) that, after complete dissolution, is significantly below the concentration causing cytotoxicity (10 µg mL-1).

Rapid UV Photo-Cross-Linking of α-Lactalbumin Hydrogel Biomaterial To Enable Wound Healing

Although both the function and biocompatibility of protein-based biomaterials are better than those of synthetic materials, their usage as medical material is currently limited by their high costs, low yield, and low batch-to-batch reproducibility. In this article, we show how α-lactalbumin (α-LA), rich in tryptophan, was used to produce a novel type of naturally occurring, protein-based biomaterial suitable for wound dressing. To create a photo-cross-linkable polymer, α-LA was methacrylated at a 100-g batch scale with >95% conversion and 90% yield. α-LAMA was further processed using photo-cross-linking-based advanced processing techniques such as microfluidics and 3D printing to create injectable hydrogels, monodispersed microspheres, and patterned scaffolds. The obtained α-LAMA hydrogels show promising biocompatibility and degradability during in vivo testing. Additionally, the α-LAMA hydrogel can accelerate post-traumatic wound healing and promote new tissue regeneration. In conclusion, cheap and safe α-LAMA-based biomaterials could be produced, and they have a beneficial effect on wound healing. As a result, there may arise a potential partnership between the dairy industry and the development of pharmaceuticals.

Bioadhesives with Antimicrobial Properties

Bioadhesives with antimicrobial properties enable easier and safer treatment of wounds as compared to the traditional methods such as suturing and stapling. Composed of natural or synthetic polymers, these bioadhesives seal wounds and facilitate healing while preventing infections through the activity of locally released antimicrobial drugs, nanocomponents, or inherently antimicrobial polers. Although many different materials and strategies are employed to develop antimicrobial bioadhesives, the design of these biomaterials necessitates a prudent approach as achieving all the required properties including optimal adhesive and cohesive properties, biocompatibility, and antimicrobial activity can be challenging. Designing antimicrobial bioadhesives with tunable physical, chemical, and biological properties will shed light on the path for future advancement of bioadhesives with antimicrobial properties. In this review, the requirements and commonly used strategies for developing bioadhesives with antimicrobial properties are discussed. In particular, different methods for their synthesis and their experimental and clinical applications on a variety of organs are reviewed. Advances in the design of bioadhesives with antimicrobial properties will pave the way for a better management of wounds to increase positive clinical outcomes.

Antibacterial and pH-sensitive methacrylate poly-L-Arginine/poly (β-amino ester) polymer for soft tissue engineering

During the last decade, pH-sensitive biomaterials containing antibacterial agents have grown exponentially in soft tissue engineering. The aim of this study is to synthesize a biodegradable pH sensitive and antibacterial hydrogel with adjustable mechanical and physical properties for soft tissue engineering. This biodegradable copolymer hydrogel was made of Poly-L-Arginine methacrylate (Poly-L-ArgMA) and different poly (β- amino ester) (PβAE) polymers. PβAE was prepared with four different diacrylate/diamine monomers including; 1.1:1 (PβAE1), 1.5:1 (PβAE1.5), 2:1 (PβAE2), and 3:1 (PβAE3), which was UV cross-linked using dimethoxy phenyl-acetophenone agent. These PβAE were then used for preparation of Poly-L-ArgMA/PβAE polymers and revealed a tunable swelling ratio, depending on the pH conditions. Noticeably, the swelling ratio increased by 1.5 times when the pH decreased from 7.4 to 5.6 in the Poly-L-ArgMA/PβAE1.5 sample. Also, the controllable degradation rate and different mechanical properties were obtained, depending on the PβAE monomer ratio. Noticeably, the tensile strength of the PβAE hydrogel increased from 0.10 ± 0.04 MPa to 2.42 ± 0.3 MPa, when the acrylate/diamine monomer molar ratio increased from 1.1:1 to 3:1. In addition, Poly-L-ArgMA/PβAE samples significantly improved L929 cell viability, attachment and proliferation. Poly-L-ArgMA also enhanced the antibacterial activities of PβAE against both Escherichia coli (~5.1 times) and Staphylococcus aureus (~2.7 times). In summary, the antibacterial and pH-sensitive Poly-L-ArgMA/PβAE1.5 with suitable mechanical, degradation and biological properties could be an appropriate candidate for soft tissue engineering, specifically wound healing applications.

White-light crosslinkable milk protein bioadhesive with ultrafast gelation for first-aid wound treatment

BACKGROUND

Post-traumatic massive hemorrhage demands immediately available first-aid supplies with reduced operation time and good surgical compliance. In-situ crosslinking gels that are flexibly adapting to the wound shape have a promising potential, but it is still hard to achieve fast gelation, on-demand adhesion, and wide feasibility at the same time.

METHODS

A white-light crosslinkable natural milk-derived casein hydrogel bioadhesive is presented for the first time. Benefiting from abundant tyrosine residues, casein hydrogel bioadhesive was synthesized by forming di-tyrosine bonds under white light with a ruthenium-based catalyst. We firstly optimized the concentration of proteins and initiators to achieve faster gelation and higher mechanical strength. Then, we examined the degradation, cytotoxicity, tissue adhesion, hemostasis, and wound healing ability of the casein hydrogels to study their potential to be used as bioadhesives.

RESULT

Rapid gelation of casein hydrogel is initiated with an outdoor flashlight, a cellphone flashlight, or an endoscopy lamp, which facilitates its usage during first-aid and minimally invasive operations. The rapid gelation enables 3D printing of the casein hydrogel and excellent hemostasis even during liver hemorrhage due to section injury. The covalent binding between casein and tissue enables robust adhesion which can withstand more than 180 mmHg blood pressure. Moreover, the casein-based hydrogel can facilitate post-traumatic wound healing caused by trauma due to its biocompatibility.

CONCLUSION

Casein-based bioadhesives developed in this study pave a way for broad and practical application in emergency wound management.

A broad-spectrum antibacterial and tough hydrogel dressing accelerates healing of infected wound in vivo

Infection can disturb the wound healing process and lead to poor skin regeneration, chronic wound, septicemia and even death. To combat the multi-drug resistance bacteria or fungi, it is urgent and necessary to develop advanced antimicrobial wound dressings. In this study, a composite hydrogel dressing composed of polyvinyl alcohol (PVA), agarose, glycerol and antibacterial hyperbranched polylysine (HBPL) was prepared by a freeze-thawing method. The hydrogel showed robust mechanical properties, and the HBPL in the hydrogel displayed effective and broad-spectrum antimicrobial properties to bacteria and fungi as well as biofilms. The composite hydrogel exhibited good biocompatibility with respect to the levels of cells, blood, tissue and main organs. In an animal experiment of an infected wound model, the hydrogel significantly eliminated the infection and accelerated the wound regeneration with better tissue morphology and angiogenesis. The hydrogel also successfully achieved scalable production of over 600 g with a yield over 90 %, suggesting the great potential for the application in practice.

Scalable Milk-Derived Whey Protein Hydrogel as an Implantable Biomaterial

There are limited naturally derived protein biomaterials for the available medical implants. High cost, low yield, and batch-to-batch inconsistency, as well as intrinsically differing bioactivity in some of the proteins, make them less beneficial as common implant materials compared to their synthetic counterparts. Here, we present a milk-derived whey protein isolate (WPI) as a new kind of natural protein-based biomaterial for medical implants. The WPI was methacrylated at 100 g bench scale, >95% conversion, and 90% yield to generate a photo-cross-linkable material. WPI-MA was further processed into injectable hydrogels, monodispersed microspheres, and patterned scaffolds with photo-cross-linking-based advanced processing methods including microfluidics and 3D printing. In vivo evaluation of the WPI-MA hydrogels showed promising biocompatibility and degradability. Intramyocardial implantation of injectable WPI-MA hydrogels in a model of myocardial infarction attenuated the pathological changes in the left ventricle. Our results indicate a possible therapeutic value of WPI-based biomaterials and give rise to a potential collaboration between the dairy industry and the production of medical therapeutics.