Smart Materials in Medicine最新文献

A multitude of autogenous/allogeneic and semi-synthetic bone graft materials have been developed to reconstruct the defective bone tissue but with high bio-cost and potential environmental pollution. With high calcium content and several trace elements, chicken eggshells are no longer considered as wastes but attractive sources of high-value-added biomaterials. This study used chicken eggshells and synthetic hydroxyapatite (HAp) to synthesize amorphous calcium phosphate (ACP) bone graft materials, namely Control and Eggshell. The physiochemical characteristics, biosafety, and immunocompatibility of synthetic ACP particles were inspected. Their osteogenic activity was further investigated in a novel osteoblastic spheroids model. Eggshell ACP particles exhibited ideal cytocompatibility compared to the control ACP and were more resistant to re-crystallization. In osteoblastic spheroids, Eggshell ACP mediated typical osteogenic mRNA profiles of MC-3T3-E1 cells, accompanied by the increased formation of mineralized nodules and boosted synthesis of ECM proteins represented by OPN and collagen I. This study establishes a promising technique to synthesize stable, safe, and osteoinductive ACP graft particles from eggshell waste. Furthermore, the osteoblastic spheroids constructed in the present study provide a more practical model for biomaterial research, which reflect the three-dimensional interaction between host bone tissue and graft materials more realistically.

In recent decades, great progress has been made in regenerative medicine with the development of various functional scaffolds, many of which have been put into practical clinical applications. In this process, biomaterials with excellent properties have played an important role, such as medical metal materials, bioceramics, polymers, etc. Among them, melanin-like polymer polydopamine (PDA) attracts increasing scientific interest and shows good clinical application potential: i) PDA can be used as coating material to facilitate the loading of various bioactive molecules; ii) PDA can be applied as the main constituent material of scaffolds to optimize the performances. In this review, the preparation method and polymerization mechanism of PDA are first outlined, and then the advantages of PDA, including good biocompatibility, strong adhesion, antioxidant property, and excellent photothermal properties, are introduced. Next, this review highlights the significant applications of PDA in regenerative medicine, mainly focusing on wound healing, bone repair and regeneration, as well as different forms of tissue engineering. Finally, challenges and prospects on future clinical applications of PDA in regenerative medicine are discussed.

3D bioprinting technology can rapidly process cell-loaded biomaterials to prepare personalized scaffolds for repairing defective tissues, tissue regeneration, and even printing tissues or organs. 3D bioprinting relies on bioinks with appropriate rheology and cytocompatibility, and hydrogels are among the most promising bioink materials for 3D bioprinting. Among many hydrogel precursor materials, hyaluronic acid (HA) stands out due to its excellent physicochemical and biological properties, such as biocompatibility, hydrophilicity, non-immunogenicity, and complete biodegradability, and has become the most attractive hydrogel precursor for bioinks. In this review, we discuss the strategies adopted for the application of HA-based hydrogels as bioinks, including printability, improving their mechanical properties, and printing with loaded cells. Finally, we summarize the application of 3D bioprinted HA-based hydrogels in various tissue engineering applications in recent years, with the aim to provide fresh inspiration for further development of HA-based hydrogels for 3D bioprinting.

Nanodendrite particles (NDs) with densely branched structures and biomimetic architectures have exhibited great promise in tumor therapy owing to their prolonged in vivo circulation time and exceptional photothermal efficiency. Nevertheless, traditional NDs are deficient in terms of specific surface modification and targeting tumors, which restrict their potential for broader clinical applications. Here, we developed coronavirus-like gold NDs through a seed-mediated approach and using silk fibroin (SF) as a capping agent. Our results demonstrate that these NDs have a favorable drug-loading capacity (∼65.25%) and light-triggered release characteristics of doxorubicin hydrochloride (DOX). Additionally, NDs functionalized with specific probes exhibited exceptional surface-enhanced Raman scattering (SERS) characteristics, enabling high-sensitivity Raman imaging of unstained single cells. Moreover, these NDs allowed for real-time monitoring of endocytic NDs for over 24 ​h. Furthermore, ND@DOX conjugated with tumor-targeting peptides exhibited mild hyperthermia, minimal cytotoxicity, and effective targeting towards cancer cells in vitro, as well as responsiveness to the tumor microenvironment (TME) in vivo. These unique properties led to the highest level of synergistic tumor-killing efficiency when stimulated by a near-infrared (NIR) laser at 808 ​nm. Therefore, our virus-like ND functionalized with SF presents a novel type of nanocarrier that exhibits significant potential for synergistic applications in precision medicine.

Brain injury often caused irreversible loss of neural tissue and resulted in serious neurological disability. Owing to the extreme complexity of the brain, it is still challenging to regenerate the brain tissue from injury and restore its normal function. Growth factors are critical signaling molecules that promote endogenous neural stem/progenitor cells (NSPCs) proliferation, migration and differentiation, resulting in functional brain recovery from injury. However, the labile nature of growth factor motivated us to develop advanced growth factor delivery strategies to precisely control over its release profile in vivo. In this review, we will discuss growth factor delivery via biomaterials for brain regeneration after injury. This review begins with an overview of some major forms of brain injury. The characteristic properties of growth factors are described to provide a biological basis for their use in the brain regeneration. The specific biomaterials that generally used for delivering growth factor to treat brain injury are also detailed summarized. In particular, we focus on an engineering strategy that promote endogenous repair by creating growth factor concentration gradients in vivo. The last part of the review introduces current challenges and perspectives for growth factor delivery via biomaterials.

Three-dimensional (3D) printing can construct products with accurate complex architecture. Engineered bone tissues that can promote vascularization and regulate directed differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) are considered as an ideal substitute the healing of bone for bone defects treatment. Herein, we fabricated a 3D printed BMSCs-laden scaffold using methacrylated gelatin and methacrylated silk fibroin (GelMA/SFMA) based bioinks along with localized sustained release of a small molecule drug fingolimod (FTY-720) for the synergistic interactions of vascularization and osteogenesis during bone repair. The GelMA/SFMA bioink showed significant advantages due to their tunable rheology, rapid thermal crosslinking, and improved shape fidelity following bioprinting. The in vitro experiments demonstrated that high cell viability of cells-laden constructs, while FTY-720-containing scaffolds significantly promoted migration and induced tube-like structure formation of human umbilical vein endothelial cells (HUVECs) as well as expressed high osteogenic-related genes expression of BMSCs. The implantation in a critical-size rat cranial defect model further revealed that FTY-720-loaded scaffolds significantly promoted vascularization and bone regeneration. Furthermore, scaffolds carrying BMSCs and FTY-720 were more osteogenic in vivo than scaffolds carrying BMSCs alone. Therefore, the constructed BMSCs-laden and FTY-720-loaded GelMA/SFMA scaffolds would be an ideal candidate with required structure and desired function for vascularization of bone regeneration.

Zinc (Zn) is a new generation of biodegradable metal as temporary biomedical implants with a promising degradation rate. However, its clinical applications have been limited because of the insufficient mechanical properties. Considering the degradation property and biocompatibility, we proposed Zn–Sr alloys after extrusion treatments to simultaneously improve the mechanical strength and ductility. The in vitro and in vivo degradation and biocompatibility were also evaluated using electrochemical and immersion corrosion tests, various cell and bacterial models, together with subcutaneous and femoral implantations in rats. Results showed that the extruded Zn-0.7Sr alloys exhibited two times higher mechanical strengths (∼120 ​MPa) and better ductility (∼10%) than the pure Zn counterparts. The Zn–Sr alloys provided enhanced in vitro and in vivo biocompatibility along with promising antibacterial properties.

Magnesium (Mg) alloy has received thorough attention in the biomedical field due to its excellent mechanical properties, good biocompatibility, and biodegradability. However, Mg alloy usually shows excessive degradation rate in the physiological environment owning to its active chemical nature. At the same time, the hydrogen generated by the degradation of Mg will increase the pH of local tissues, which will harm the growth of surrounding tissues. Given the above problems, it has become a research hotspot to obtain various properties of Mg alloy for clinical application by surface modification. In this paper, the surface coatings of Mg alloy are reviewed according to different types, including metals (metal oxides, metal hydroxides), inorganic non-metals, polymers (synthetic polymers and natural polymers), and composite coatings. The preparation methods, corrosion resistance, and biocompatibility of different types of coatings are discussed, and the development prospect of biomedical Mg alloy surface coatings is also predicted.