Biomaterials Science最新文献

Over eight million surgical procedures are conducted annually in the United Stats to address organ failure or tissue losses. In response to this pressing need, recent medical advancements have significantly improved patient outcomes, primarily through innovative reconstructive surgeries utilizing tissue grafting techniques. Despite tremendous efforts, repairing damaged tissues remains a major clinical challenge for bioengineers and clinicians. 3D bioprinting is an additive manufacturing technique that holds significant promise for creating intricately detailed constructs of tissues, thereby bridging the gap between engineered and actual tissue constructs. In contrast to non-biological printing, 3D bioprinting introduces added intricacies, including considerations for material selection, cell types, growth, and differentiation factors. However, technical challenges arise, particularly concerning the delicate nature of living cells in bioink for tissue construction and limited knowledge about the cell fate processes in such a complex biomechanical environment. A bioink must have appropriate viscoelastic and rheological properties to mimic the native tissue microenvironment and attain desired biomechanical properties. Hence, the properties of bioink play a vital role in the success of 3D bioprinted substitutes. This review comprehensively delves into the scientific aspects of tissue-centric or tissue-specific bioinks and sheds light on the current challenges of the translation of bioinks and bioprinting.

The development of safe and efficient hemostatic materials is medically important to prevent death due to trauma bleeding. Exploiting the synergistic effect between the D-periodic functional domain of collagen fibrils on platelet activation and cationic chitosan on erythrocyte aggregation is expected to develop performance-enhanced hemostatic materials. In this study, we prepared collagen fibrils and chitosan composite hemostatic materials by modulating the self-assembled bionic fibrillation of collagen with different degrees of deacetylation (DD, 50%, 70% and 85%) of chitosan. The findings indicated that chitosan promoted collagen self-assembly, with all the collagen fibrils demonstrating a typical D-periodical structure similar to that of the native collagen. Furthermore, the composite demonstrated enhanced structural integrity and procoagulant capacity along with good biocompatibility. Notably, the fibrillar composites with 70% DD of chitosan exhibited optimal mechanical properties, procoagulant activity, and adhesion of erythrocytes and platelets. Compared to pure collagen fibrils and the commercial hemostatic agent Celox™, the collagen/chitosan fibrillar composite treatment significantly accelerated hemostasis in the rat tail amputation model and liver injury model. This research offers new insights into the development of hemostatic materials and indicates that collagen-chitosan composites hold promising potential for clinical applications.

Light-based patterning of synthetic and biological hydrogels enables precise spatial and temporal control over the formation of chemical bonds. However, photoinitiators are typically used to generate free radicals, which are detrimental to human cells. Here, we report a photoinitiator- and radical-free method based on ortho-nitrobenzyl alcohol (oNBA) photolysis, which gives rise to highly reactive nitroso and benzaldehyde groups. Synthetic hydrogel and pristine protein networks can rapidly form in the presence of these photo-generated reactive species. Thiol -oNBA bonds yield dynamic hydrogel networks (DHNs) via N-semimercaptal linkages that exhibit thixotropy, stress relaxation, and on-demand reversible gel-to-liquid transitions, while amine-oNBA bonds can be exploited to crosslink pristine proteins, such as gelatin and fibrinogen, by targeting their primary amines. Since this approach does not require incorporation of photoreactive moieties along the backbone, the resulting crosslinked proteins are well suited for bioadhesives. Our photoinitiator-free platform provides a versatile approach for rapidly creating synthetic and biological hydrogels for applications ranging from tissue engineering to biomedical devices.

Precise control of cellular temperature at the microscale is crucial for developing novel neurostimulation techniques. Here, the effect of local heat on the electrophysiological properties of primary neuronal cultures and HEK293 cells at the subcellular level using a cutting-edge micrometer-scale thermal probe, the diamond heater-thermometer (DHT), is studied. A new mode of local heat action on a living cell, thermal-capture mode (TCM), is discovered using the DHT probe. In TCM, the application of a 50 °C temperature step induces a great increase in cellular response, allowing the cell to be thermally captured and depolarized by up to 20 mV. This thermal effect is attributed to local phase changes in the phospholipid membrane, enabling precise and reproducible modulation of cell activity. The TCM is shown to open up new opportunities for thermal cell stimulation. DHT reliably triggers action potentials (APs) in neurons at rates up to 30 Hz, demonstrating the ability to control cell excitability with millisecond and sub-millisecond resolution. AP shape is modulated by local heat as well. The ability to precisely control the AP shape and rate via thermal-capture mode opens new avenues for non-invasive, localized neurostimulation techniques, particularly in controlling neuron excitability.

The popularity of medicinal plants, which have a unique system and are mostly used in compound form for the prevention and treatment of a wide range of diseases, is growing worldwide. In recent years, with advances in chemical separation and structural analysis techniques, many of the major bioactive molecules of medicinal plants have been identified. However, the active ingredients in medicinal plants often possess chemical characteristics, including poor water solubility, stability and bioavailability, which limit their therapeutic applications. To address this problem, self-assembly of small molecules from medicinal food sources provides a new strategy. Driven by various types of acting forces, medicinal small molecules with modifiable groups, multiple sites of action, hydrophobic side chains, and rigid backbones with self-assembly properties are able to form various supramolecular network hydrogels, nanoparticles, micelles, and other self-assemblies. This review first summarizes the forms of self-assemblies such as supramolecular network hydrogels, nanoparticles, and micelles at the level of the action site, and discusses the recent studies on the active ingredients in medicinal plants that can be used for self-assembly, in addition to summarizing the advantages of self-assemblies for a variety of disease applications, including wound healing, antitumor, anticancer, and diabetes mellitus. Finally, the problems of self-assemblers and the possible directions for future development are presented. We firmly believe that self-assemblers have the potential to develop effective compounds from drug-food homologous plants, providing valuable information for drug research and new strategies and perspectives for the modernization of Chinese medicine.

The failure to treat deep skin wounds can result in significant complications, and the limitations of current clinical treatments highlight the pressing need for the development of new deep wound healing materials. In this study, a series of three-dimensional structured PLCL/ADM composite aerogels were fabricated by electrospinning and subsequently characterized for their microstructure, compression mechanics, exudate absorption, and hemostatic properties. Additionally, the growth of HSFs and HUVECs, which are involved in wound repair, was observed in the aerogels. The composite aerogel was subsequently employed in wound repair experiments on rat full-thickness skin with the objective of observing the wound healing rate and examining histological utilizing H&E, Masson, CD31, and COL-I staining. The findings indicated that the PLCL/ADM composite aerogel with a 10% concentration exhibited uniform pore size distribution, a good three-dimensional structure, and compression properties comparable to those of human skin, which could effectively absorb exudate and exert hemostatic effect. In vivo experiment results demonstrated that the aerogel exhibited superior efficacy to conventional oil-gauze overlay therapy and ADM aerogel in promoting wound healing and could facilitate rapid, high-quality in situ repair of deep wounds, thereby offering a novel approach for skin tissue engineering and clinical wound treatment.

Oral health is essential to general health. The diagnosis of dental diseases and treatment planning of dental care need to be straightforward and accurate. Recent studies have reported the use of aptamers in dentistry to achieve a simple diagnosis and facilitate therapy. Aptamers comprise nucleic acid sequences that possess a strong affinity for their target. Synthesized chemically, aptamers have several advantages, including smaller size, higher stability, and lower immunogenicity compared with monoclonal antibodies. They can be used to detect biomarkers in saliva and the presence of various pathogens, or can be used as a targeted drug delivery system for disease treatment. This review highlights current research on aptamers for dental care, especially the recent progress in oral disease diagnosis and therapeutics. The challenges and unresolved problems faced by the clinical use of aptamers are also discussed. In the future, the clinical applications of aptamers will be further extended to include, for example, dental indications and regenerative dentistry.

Polypropylene (PP) mesh is a widely used prosthetic material in hernia repair due to its excellent mechanical properties and appropriate biocompatibility. However, its application is limited due to severe adhesion between the mesh and the abdominal viscera, leading to complications such as chronic pain, intestinal obstruction, and hernia recurrence. Currently, building anti-adhesive PP mesh remains a formidable challenge. In this work, a novel anti-adhesive PP mesh (PPM/GelMA/TA) was designed with a simple and efficient in situ gel of GelMA solution on the surface of PP mesh and further crosslinking of tannic acid (TA). It was demonstrated that PPM/GelMA/TA has good biocompatibility and excellent antioxidant property and effectively activates the polarization of macrophages toward the M2 phenotype in vitro. In addition, PPM/GelMA/TA could inhibit the growth of bacteria, which is of great significance for preventing postoperative infections. Furthermore, in the repair of full-thickness abdominal wall defects in rats, PPM/GelMA/TA reduced inflammation, promoted macrophage M2 polarization, and collagen deposition and angiogenesis so that does not cause any abdominal adhesion compared with PP mesh. As a result, our PPM/GelMA/TA shows an attractive prospect in the treatment of abdominal wall defect without adhesions.

Tumors pose a serious threat to people's lives and health, and the complex tumor microenvironment is the biggest obstacle to their treatment. In contrast to the basic protein matrices typically employed in 2D or 3D cell culture systems, decellularized extracellular matrix (dECM) can create complex microenvironments. In this study, a combination of physicochemical methods was established to obtain liver decellularized extracellular matrix scaffolds (dLECMs) to provide mechanical support and cell adhesion sites. By co-culturing tumor cells, tumor-associated stromal cells and immune cells, an in vitro 3D tumor model with a biomimetic immune microenvironment was constructed. By utilizing microenvironment data obtained from human liver tumor tissues and refining the double seeding modeling process, 3D in vitro liver tumor-like tissues with a tumor immune microenvironment (TIME) were obtained and designated as reconstructed human liver cancer (RHLC). These tissues demonstrated similar tumor characteristics and exhibited satisfactory physiological functionality. The results of metabolic characterisation and mouse tumorigenicity testing verified that the constructed RHLC significantly increased in vitro drug resistance while also closely mimicking in vivo tissue metabolism. This opens up new possibilities for creating effective in vitro models for screening chemotherapy drugs.

Immune-mediated glomerular diseases lead to chronic kidney disease (CKD), primarily through mechanisms such as immune cell overactivation, mitochondrial dysfunction and imbalance of reactive oxygen species (ROS). We have developed an ultra-small nanodrug composed of Mn₃O₄ nanoparticles which is functionalized with biocompatible ligand citrate (C-Mn₃O₄ NPs) to maintain cellular redox balance in an animal model of oxidative injury. Furthermore, this ultra-small nanodrug, loaded with tacrolimus (Tac), regulated the activity of immune cells. We established a doxorubicin (DOX)-induced CKD model in SD rats using conditions of oxidative distress. The results demonstrate the ROS scavenging capability of Mn₃O₄ NPs, which mimics enzymatic activity, and the immunosuppressive effect of tacrolimus. This combination promotes targeted accumulation in the renal region with sustained drug release through the enhanced permeability and retention (EPR) effect. Tac@C-Mn₃O₄ protects the structural and functional integrity of mitochondria from oxidative damage while eliminating excess ROS to maintain cellular redox homeostasis, thereby suppressing the overexpression of pro-inflammatory cytokines to restore kidney function and preserve a normal kidney structure, reducing inflammation and regulating antioxidant stress pathways. This dual-pronged treatment strategy also provides novel strategies for CKD management and demonstrates substantial potential for clinical translational application.