As nanoscale materials with the function of catalyzing substrates through enzymatic kinetics, nanozymes are regarded as potential alternatives to natural enzymes. Compared to protein-based enzymes, nanozymes exhibit attractive characteristics of low preparation cost, robust activity, flexible performance adjustment, and versatile functionalization. These advantages endow them with wide use from biochemical sensing and environmental remediation to medical theranostics. Especially in biomedical diagnosis, the feature of catalytic signal amplification provided by nanozymes makes them function as emerging labels for the detection of biomarkers and diseases, with rapid developments observed in recent years. To provide a comprehensive overview of recent progress made in this dynamic field, here an overview of biomedical diagnosis enabled by nanozymes is provided. This review first summarizes the synthesis of nanozyme materials and then discusses the main strategies applied to enhance their catalytic activity and specificity. Subsequently, representative utilization of nanozymes combined with biological elements in disease diagnosis is reviewed, including the detection of biomarkers related to metabolic, cardiovascular, nervous, and digestive diseases as well as cancers. Finally, some development trends in nanozyme-enabled biomedical diagnosis are highlighted, and corresponding challenges are also pointed out, aiming to inspire future efforts to further advance this promising field.

Metal-organic frameworks (MOFs) are composite crystalline materials created through the coordination of metal ions and organic ligands. MOFs have attracted extensive attention in the biomedical field based on the advantages of internal porosity, customizable porosity, and facile surface modification. This review examines the utilization of MOFs in drug delivery systems, focusing on the research progress from the aspects of coloading drug systems, intelligent responsive carriers, biological macromolecule stabilizers, self-driving micro/nanomotors, and multifunctional living carriers. In addition, the current challenges the research faces are also discussed. The review aims to provide a reference for the further application of MOFs as advanced drug delivery systems.

The application of bone grafting materials in bone tissue engineering is paramount for treating severe bone defects. In this comprehensive review, we explore the significance and novelty of utilizing bioactive polymers as grafts for successful bone repair. Unlike metals and ceramics, polymers offer inherent biodegradability and biocompatibility, mimicking the native extracellular matrix of bone. While these polymeric micro-nano materials may face challenges such as mechanical strength, various fabrication techniques are available to overcome these shortcomings. Our study not only investigates diverse biopolymeric materials but also illuminates innovative fabrication methods, highlighting their importance in advancing bone tissue engineering.

Cyanobacteria are the only prokaryotes capable of performing oxygenic photosynthesis on Earth. Besides their traditional roles serving as primary producers, cyanobacteria also synthesize abundant secondary metabolites including carotenoids, alkaloids, peptides, which have been reported to possess medicinal potentials. More importantly, the advancement of synthetic biology technology has further expanded their potential biomedical applications especially using living/engineered cyanobacteria, providing promising and attractive strategies for future disease treatments. To improve the understanding and to facilitate future applications, this review aims to discuss the current status and future prospects of cyanobacterial-based biomedical engineering. Firstly, specific properties of cyanobacteria related with biomedical applications like their natural products of bioactive compounds and heavy metal adsorption were concluded. Subsequently, based on these properties of cyanobacteria, we discussed the progress of their applications in various disease models like hypoxia microenvironment alleviation, wound healing, drug delivery, and so on. Finally, the future prospects including further exploration of cyanobacteria secondary metabolites, the integration of bioactive compounds synthesized by cyanobacteria in situ with medical diagnosis and treatment, and the optimization of in vivo application were critically presented. The review will promote the studies related with cyanobacteria-based biomedical engineering and its practical application in clinical trials in the future.

The utilization of extracellular vesicles (EVs) in wound healing has been well-documented. However, the direct administration of free EVs via subcutaneous injection at wound sites may result in the rapid dissipation of bioactive components and diminished therapeutic efficacy. Functionalized hydrogels provide effective protection, as well as ensure the sustained release and bioactivity of EVs during the wound healing process, making them an ideal candidate material for delivering EVs. In this review, we introduce the mechanisms by which EVs accelerate wound healing, and then elaborate on the construction strategies for engineered EVs. Subsequently, we discuss the synthesis strategies and application of hydrogels as delivery systems for the sustained release of EVs to enhance complicated wound healing. Furthermore, in the face of complicated wounds, functionalized hydrogels with specific wound microenvironment regulation capabilities, such as antimicrobial, anti-inflammatory, and immune regulation, used for loading engineered EVs, provide potential approaches to addressing these healing challenges. Ultimately, we deliberate on potential future trajectories and outlooks, offering a fresh viewpoint on the advancement of artificial intelligence (AI)-energized materials and 3D bio-printed multifunctional hydrogel-based engineered EVs delivery dressings for biomedical applications.

The liver is the most important metabolic organ in the body. While mouse models and cell lines have further deepened our understanding of liver biology and related diseases, they are flawed in replicating key aspects of human liver tissue, particularly its complex structure and metabolic functions. The organoid model represents a major breakthrough in cell biology that revolutionized biomedical research. Organoids are in vitro three-dimensional (3D) physiological structures that recapitulate the morphological and functional characteristics of tissues in vivo, and have significant advantages over traditional cell culture methods. In this review, we discuss the generation strategies and current advances in the field focusing on their application in regenerative medicine, drug discovery and modeling diseases.

MXenes are two-dimensional (2D) transition metal-based carbides, nitrides, and carbonitrides that are synthesized from its precursor MAX phase. The selective etching of the \"A\" from the MAX phase yields multi-functional MXenes that hold promise in a wide range of energy-based applications and biomedical applications. Based on its intended application, MXenes are prepared as multilayered sheets, monolayer flakes, and quantum dots. Conventionally, MXenes are prepared using hydrofluoric (HF) acid etching; however, the use of HF impedes its effective use in biomedical applications. This calls for the use of nontoxic HF-free synthesis protocols to prepare MXenes safe for biological use. Therefore, we have discussed a facile process to synthesize biocompatible, HF-free MXene nanosheets and quantum dots.

Collagen and gelatin are essential natural biopolymers commonly utilized in biomaterials and tissue engineering because of their excellent physicochemical and biocompatibility properties. They can be used either in combination with other biomacromolecules or particles or even exclusively for the enhancement of bone regeneration or for the development of biomimetic scaffolds. Collagen or gelatin derivatives can be transformed into nanofibrous materials with porous micro- or nanostructures and superior mechanical properties and biocompatibility using electrospinning technology. Specific attention was recently paid to electrospun mats of such biopolymers, due to their high ratio of surface area to volume, as well as their biocompatibility, biodegradability, and low immunogenicity. The fiber mats with submicro- and nanometer scale can replicate the extracellular matrix structure of human tissues and organs, making them highly suitable for use in tissue engineering due to their exceptional bioaffinity. The drawbacks may include rapid degradation and complete dissolution in aqueous media. The use of gelatin/collagen electrospun nanofibers in this form is thus greatly restricted for biomedicine. Therefore, the cross-linking of these fibers is necessary for controlling their aqueous solubility. This led to enhanced biological characteristics of the fibers, rendering them excellent options for various biomedical uses. The objective of this review is to highlight the key research related to the electrospinning of collagen and gelatin, as well as their applications in the biomedical field. The review features a detailed examination of the electrospinning fiber mats, showcasing their varying structures and performances resulting from diverse solvents, electrospinning processes, and cross-linking methods. Judiciously selected examples from literature will be presented to demonstrate major advantages of such biofibers. The current developments and difficulties in this area of research are also being addressed.

Although the use of thermoplastic polyurethane (Tpu) nanofiber mats as wound dressings is of great interest due to their mechanical properties, they are hindered by their poor wettability and bioavailability. In this study, we aimed to improve the cellular affinity of Tpu nanofiber mats for skin disorders by incorporating extracted collagen (Col) from tendons and physically mixed with a layer of phytoceramides (Phyto) to produce TpuCol@X-Phyto mats in which the weight % of Phyto relatively to the weight of the solution was X = 0.5, 1.0, or 1.5 wt% via facile electrospinning approach. The collective observations strongly indicate the successful incorporation and retention of Phyto within the TpuCol architecture. An increase in the Phyto concentration decreased the water contact angle from 69.4° ± 3.47° to 57.9° ± 2.89°, demonstrating improvement in the hydrophilicity of Tpu and binary blend TpuCol nanofiber mats. The mechanical property of 1.0 wt% Phyto aligns with practical requirements owing to the presence of two hydroxyl groups and the amide linkage likely contributing to various hydrogen bonds, providing mechanical strength to the channel structure and a degree of rigidity essential for transmitting mechanical stress. The proliferation of human skin fibroblast (HSF) peaked significantly 100 % with TpuCol@X-Phyto mats coated for X =1.0 and 1.5 wt% of Phyto. Electrospun scaffolds with the highest Phyto content have shown the lowest degree of hemolysis, demonstrating the high level of compatibility between them and blood. The TpuCol@1.5Phyto mat also demonstrated higher efficacy in antibacterial and antioxidant activities, achieving a rate of DPPH radical scavenging of 83.3 % for this latter property. The most notable wound closure among all tested formulations was attributed to higher Phyto. Thus, the developed TpuCol@1.5Phyto nanofiber formula exhibited enhanced healing in an in vitro epidermal model.

Background Selenium nanoparticles (SeNPs) are one of the metal nanoparticles that have been widely utilized for their anti-microbial, anti-oxidant, anti-inflammatory activities, and other biomedical applications. Tridax procumbens (TP) stem extract is a promising herb species rich in flavonoids, tannins, alkaloids, phytosterols, and hydroxycinnamates, which play a major role in wound healing applications.  Aim The study aims to synthesize SeNPs using TP stem extract, characterizations, and its biomedical applications. Materials and methods SeNPs were synthesized using TP stem extract. The green synthesis of SeNPs was confirmed by ultraviolet-visible (UV-vis) spectra analysis. The synthesized SeNPs were characterized using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The agar well diffusion method was utilized to evaluate the anti-bacterial properties of the green synthesized SeNPs using TP stem extract. The anti-oxidant effect of SeNPs was tested using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, ferric-reducing anti-oxidant power assay (FRAP), and hydroxyl radical scavenging assay (H₂O₂). The anti-inflammatory effect was investigated using the bovine serum albumin assay and egg albumin denaturation method, and the cytotoxic effect of the green synthesized SeNPs was tested using the brine shrimp lethality (BSL) assay. Results The green synthesis of SeNPs was confirmed using different types of analysis techniques. The characterizations were done by UV-visible spectroscopy analysis, exhibiting a maximum peak at the range of 330 nm. SEM analysis revealed the shape of the nanoparticle to be hexagonal. The agar well diffusion method exhibited the anti-bacterial efficacy of SeNPs against wound microorganisms with a zone of inhibition of 14.6 mm for Escherichia coli (E. coli), 15.8 mm for Staphylococcus aureus (S. aureus), and 15.4 mm for Pseudomonas aeruginosa (P. aeruginosa). The TP stem-mediated SeNPs showed potential effects in anti-oxidant, anti-inflammatory, and cytotoxic activity, which shows very little toxicity. Conclusion Overall, the green synthesis of TP-stem-mediated SeNPs has great potential in biomedical applications. Thus, the synthesized SeNPs exhibit significant anti-bacterial efficacy against wound pathogens. The TP stem-mediated SeNPs showed potential effects in anti-oxidant, anti-inflammatory, and cytotoxic activity, which shows low toxicity. Furthermore, the green-synthesized SeNPs can be utilized in therapeutic management.