Calcium‐dependent antimicrobials: Nature‐inspired materials and designs

A Cytotoxic T Lymphocyte-Inspiring Microscale System for Cancer Immunotherapy

Adoptive T cell therapy (ACT) is an emerging cancer immunotherapy undergoing clinical evaluation, showing significant promise in the treatment of solid tumors. However, the clinical translation of ACT is hindered by its time-, labor-, and financial-consuming procedures, heterogeneity of cytotoxic T lymphocytes (CTLs), and immunosuppressive tumor microenvironment. Herein, we have developed a bionic cytotoxic T lymphocyte-inspiring microscale system (CTLiMS) composed of mesoporous silica dioxide microspheres containing membrane-disrupting boron clusters (BICs) and proapoptotic monomethyl auristatin E (MMAE) peptides. The BICs were found to disrupt the integrity of cancer cell membranes and enhance the internalization of MMAE, effectively mimicking the biological functions of perforin and granzymes released by CTLs to destroy cancer cells. As expected, the CTLiMSs demonstrated exceptional in vitro anticancer activity, inducing cancer cell apoptosis and exhibiting strong antiproliferative effects. Notably, CTLiMS treatment was demonstrated to induce immunogenic cell death of cancer cells as a result of Ca2+ and MMAE influx and subsequent production of reactive oxygen species. The animal studies demonstrated that the CTLiMS treatment led to efficient repression of the tumor growth. Furthermore, the CTLiMS administration resulted in favorable antitumor immunotherapeutic effects, as shown by significant inhibition of distant tumors, increased immune cell infiltration, and elevated plasma levels of pro-inflammatory cytokines. This pilot study using CTLiMSs for cancer immunotherapy offers an innovative bionic strategy for the future advancement of adoptive T cell therapy.

Metastable Calcium Phosphate Cluster-Involved Mineralization Process Regulated by a Dual Biomolecule System Toward the Application in Dentinal Tubules Occlusion

Dentin hypersensitivity caused by the exposure of dentinal tubules is affecting a significant portion of the population. With promising prospects, the biomimetic mineralization materials used in treating dentin hypersensitivity are expected to possess a metastable characteristic, for which they can easily penetrate the tubules and the surrounding tissues, but then occlude them via a transformation of size and phase immediately. Herein, this study develops a metastable calcium phosphate cluster (MCPC)-involved mineralization process, which is regulated by dual biological macromolecules: bovine serum albumin (BSA) and poly-L-lysine (PLL). BSA functions to stabilize the primary calcium phosphate clusters; PLL further tunes the cluster's evolution (toward larger and crystalline particles) into a metastable fashion, and meanwhile inhibits the local bacteria. Upon treatments, the system generates amorphous MCPC with ultrasmall size (1-2 nm); then they enter the deep dentinal tubules, subsequently aggregate and crystalline into immobile larger particles, which finally seal the exposed dentinal tubules. The effective occlusion of dentinal tubules as well as significant antibacterial performance are confirmed both in vivo and in vitro. This study has devised not only a regulatory approach for the evolution of mineralization-active clusters but also established an efficient method for managing dentin hypersensitivity.

Systematic review of antibacterial potential in calcium oxide and silicon oxide nanoparticles for clinical and environmental infection control

A substantial threat to worldwide health, the proliferation of antibiotic-resistant bacteria compels researchers to seek innovative antibacterial substances. This systematic review assesses the role of nanoparticles, particularly Calcium oxide and Silicon oxide nanoparticles, in infection control. The article examines the mechanisms by which these nanoparticles act against various bacteria and evaluates their potential as novel agents in infection control strategies. A systematic literature search from 2015 to 2024 encompassing Web of Science, PubMed, Wiley, Science Direct, and Google Scholar, yielded 70 publications meeting the review criteria. This comprehensive methodology provides a thorough understanding of the capabilities and limitations of Calcium oxide and Silicon oxide nanoparticles as antibacterial agents. The review aims to build a solid foundation for the utilization of nanoparticles in addressing the obstacles presented by antibiotic resistance by combining data from various investigations. Additionally, it aims to explore the safety and environmental implications associated with their use in clinical and environmental settings, providing a comprehensive analysis that may contribute to future studies and real-world applications in the field of antimicrobial technology.

Self-powered biomedical devices: biology, materials, and their interfaces

Integrating biomedical electronic devices holds profound promise for advancements in healthcare and enhancing individuals' quality of life. However, the persistent challenges associated with the traditional batteries' limited lifespan and bulkiness hinder these devices' long-term functionality and consistent power supply. Here, we delve into the biology and material interfaces in self-powered medical devices by summarizing the intrinsic electric demands in humans, analyzing material and biological mechanisms for electricity generation and storage, and discussing the pathways toward self-chargeable powering. As a result, the current challenges in material designs and biological integrations emerged to shape the future directions in advancing self-powered medical devices. This paper calls on the community to integrate biology and material science to develop self-powering medical devices and improve their clinical prospects.

3D printed sodium Alginate-Gelatin hydrogel loaded with Santalum album oil as an antibacterial Full-Thickness wound healing and scar reduction Scaffold: In vitro and in vivo study

Managing wounds and accompanying consequences like exudation and microbiological infections is challenging in clinical practice. Bioactive compounds from traditional medicinal plants help heal wounds, although their bioavailability is low. This study uses sodium alginate (SA), gelatin (G), and Santalum album oil (SAL) to 3D print a polymeric hydrogel scaffold to circumvent these difficulties. The 3D printed scaffolds showed hydrophilicity, an average pore size of 221.30 ± 19.83 µm, adequate swelling, higher mechanical strength with tensile strength (σ) of 13.5 ± 1.08 MPa, a Young's modulus of 17.53 ± 1.61 MPa, andpotential antibacterial activity against skin infection causing bacteria viz. Staphylococcus aureus (87.7 ± 4 % growth inhibition) and Pseudomonas aeruginosa (i.e. 81.96 ± 3.94 % growth inhibition). The scaffolds showed hemocompatibility, biocompatibility, and moderate biodegradability. Cytotoxicity and scratch assay showed significantly improved fibroblast viability, proliferation, and migration. In the in vivo study, the scaffolds were applied to full-thickness wounds in rat models. After 7 and 14 days of treatment, the wounds treated with the 3D-printed SA-G-SAL scaffold showed higher closure rates, lower contraction, higher-regenerated epithelium with minimal inflammation, and less scar formation compared to control groups. Thus, the 3D-printed SA-G-SAL scaffold is a promising biomaterial for wound healing with reduced scar formation.

Cellulose Acetate Membranes: Antibacterial Strategy and Application-A Review

Developing antibacterial and biodegradable cellulose acetate (CA) membrane materials is one of the main challenges in multiple application fields. CA membrane materials are widely used in gas purification, water purification, and biomedical fields due to their environmental friendliness, high chemical and mechanical stability, excellent processability, and low cost. However, antibacterial modification of CA membrane materials to enhance their utilization value in the application process has always been the direction of researchers' efforts. This review focuses on the preparation and application of antibacterial CA and its derivatives membranes, especially the types and introduction methods of antibacterial agents. First, a brief introduction of CA-based polymer membranes is presented, followed by an overview of the antibacterial agent types and their introduction methods, and antibacterial mechanisms. After that, various membranes prepared using CA-based polymers as the main matrix or as additives are discussed. Then, specific applications of antibacterial CA-based membrane materials in water purification, gas purification, biomedical, food packaging, and other fields are outlined.

In vitro corrosion and cytocompatibility of Mg-Zn-Ca alloys coated with FHA

In the field of orthopedics, it's crucial to effectively slow down the degradation rate of Mg alloys. This study aims to improve the degradation behavior of Mg-Zn-Ca alloys by electrodepositing fluorohydroxyapatite (FHA). We investigated the microstructure and bond strength of the deposition, as well as degradation and cellular reactions. After 15-30 days of degradation in Hanks solution, FHA deposited alloys showed enhanced stability and less pH change. The strong interfacial bond between FHA and the Mg-Zn-Ca substrate was verified through scratch tests (Critical loads: 10.73 ± 0.014 N in Mg-Zn-0.5Ca alloys). Cellular studies demonstrated that FHA-coated alloys exhibited good cytocompatibility and promoted the growth of MC3T3-E1 cells. Further tests showed FHA-coated alloys owed improved early bone mineralization and osteogenic properties, especially in Mg-Zn-0.5Ca. This research highlighted the potential of FHA-coated Mg-Zn-0.5Ca alloys in orthopedics applications.