Transition metal oxides as the next generation of 2-D materials have attracted widespread attention because of their unique electrochemical properties. In this study, the preparation of metal oxides (MO) involves a two-step process of a hydrothermal reaction with subsequent air annealing. First, the transition metal dichalcogenides (TMD) nanosheets were prepared by a hydrothermal method. Subsequently, the TMD nanosheets were converted to MO nanosheets via the thermal annealing method. In addition, Au@NFs nanocomposites were also prepared using an efficiently combined approach of hydrothermal process and in situ chemical synthesis method. Both XRD and TEM results illustrated that MO nanosheets and Au@NFs nanocomposites were successfully prepared. For the first time, a novel electrochemical immunosensor modified with Au@NFs/MO nanocomposites was fabricated by the solution-casting method for detecting the calreticulin (CRT) biomarkers. This construction step provides a suitable and simple method for the covalent attachment of modified SPCE and anti-CRT molecules. Bio-affinity interactions between CRT biomarkers and anti-CRT molecules were investigated by CV and EIS techniques. The CV and EIS results indicated that L-Cysteine and EDC/NHS modified-Au@NFs/MO/SPCE could increase the electron transfer ability. When EN-LC/Au@NFs/MO/SPCE was sequentially modified with anti-CRT, BSA, and CRT, the Rct value gradually increased to$4433.71\ \varOmega$, indicating that these non-conductive biomolecules were successfully immobilized. This result indicated that the CRT-immunosensors were successfully fabricated. In the future, the CRT-immunosensors are expected to detect real samples.

Critical-sized bone defects are important medical problems that often do not heal themselves through the own body's repair mechanisms. Studies have shown that incorporating trace elements such as magnesium (Mg), strontium (Sr) or silicon (Si) into bone scaffolds can improve its biological activity for bone healing and regeneration. With the development in 3D printing technology, the unit structure, multi-layer structure and multi-material structure of the scaffold can be easily manipulated, which can effectively control the degradation rate of the scaffold and the appropriate strength of the implant. The aim of this study is to design a composite scaffold by combining two different materials using 3D printing, with Mg-doped calcium silicate and Sr-doped calcium silicate as the outer and inner sides of the scaffold. The scaffold can protect against the problem of premature breakdown of the overall strength caused by the initial degradation after implantation, as well as achieve a synergistic therapeutic effect by the releasing trace ions. This study further explores the potential mechanism of Mg and Sr that promote bone regeneration, in order to facilitate the future application of 3D-printed bone implants in the critical-sized bone defects.

Traditional treatment strategy for knee cartilage injuries (such as osteochondrosis dissecans, early degenerative arthritis, femoral condyle necrosis) includes mosaicplasty, which usually requires surgeons to harvest healthy cartilage tissues from other non-weight bearing joints. The development of surface modification techniques have brought a major paradigm shift for clinical bone tissue regeneration applications. In this study, we modified the surface of calcium silicate scaffolds (CS) with lithium ions (Li) via a simple immersion technique and evaluated its capabilities for bone regeneration. Li has been reported to have anti-inflammatory, osteogenic and chondrogenic capabilities via the promotion of several intracellular signalling pathways. Our results showed that Li ions could be easily coated onto the surfaces of CS scaffolds without affecting the microstructural properties of CS itself. In addition, the modifications did not affect printing capabilities of CS and porous scaffolds could be fabricated via the extrusion method. Furthermore, the presence of Li showed improvements in surface roughness and hydrophilicity, thus leading to enhanced secretion of osteochondral-related regeneration factors such as ALP, BSP and Col II proteins. Subsequent in vivo studies, including histological and micro-CT analysis confirmed that our Li-modified CS scaffolds were able to promote osteochondral regeneration. From our NGS analysis, the enhanced osteo-chondrogenic capabilities of our scaffolds were hypothesised to be influenced by paracrine exosomes. Taken together, we hoped that our study could inspire more osteochondral regeneration studies using the surface modification techniques.

Fucoidan has various biological activities, such as antioxidant, antibacterial, anti-inflammatory, antiviral, anticoagulant, antitumor and immunomodulatory activities. In view of the role of fucoidan in regulating transforming growth factor$\beta 1$related to wound repair, and helping the formation of new blood vessels and fibrous collagen matrix, it has the potential to help skin repair. Therefore, this study applied fucoidan to the development of a three-dimensional sponge dressing for skin damage repair. At present, the manufacturing process and formulation of the three-dimensional sponge dressing containing fucoidan have been developed, and its physical properties and biocompatibility have been evaluated. It is expected to contribute to the development of skin damage treatment in the future.

This study aimed to investigate the effects of human chondrocytes-laden auxetic scaffold under the cyclic tension stimulation by carrying out the decellularized extracellular matrix of rabbit meniscus (dECM) and light-curable gelatin (FGelMA) as the material substrate. The prepared photocurable bioink provided cells proliferation and morphological alterations. There was a trend to elevate cell numbers significantly compared with static culturing, and a wider spread of cell expansion can also be found at the edge of the auxetic structure. Remarkably, the scaffold designed as an auxetic structure through digital light processing and combined with cyclic tension stimulation to further promote the synergetic effect on chondrogenic-related ECM markers of chondrocytes.

The biofabricate technologies has allowed us to manufacture complex novel scaffolds for tissue regeneration. In this study, we demonstrated the incorporation of different concentrations of ceramic powder into fish gelatin methacrylate (FGelMa) bioink for the fabrication of CS/FGelMa auxetic bioscaffolds using bioprinting technology. Our results indicated that ceramic could be successfully incorporated into FGelMa bioink without effecting the structural components of FGelMa. Furthermore, it conveyed that ceramic modifications both the mechanical properties and degradation rates of the scaffolds were improved in accordance with the concentrations of ceramic upon modifications of ceramic. In addition, the presence of ceramic promoted the adhesion and proliferation of human periodontal ligament cells (hPDLs) cultured in the scaffold. Further osteogenic evaluation also confirmed that ceramic was able to enhance the osteogenic capabilities via activation of downstream intracellular factors such as pFAK/FAK and pERK/ERK. More interestingly, it was noted that the application of extrinsic biomechanical stimulation to the auxetic scaffolds further enhanced the proliferation and differentiation of hPDLs cells and secretion of osteogenicrelated markers when compared to CS/FGelMa hydrogels without tensile stimulation. This prompted us to explore the related mechanism behind this interesting phenomenon. Subsequent studies showed that biomechanical stimulation works via YAP, which is a biomechanical cue. Taken together, our results showed that novel auxetic scaffolds could be fabricated by combining different aspects of science and technology, in order to improve the future chances of clinical applications for bone regeneration.

Despite the emergence of three-dimensional printing techniques that has been considered useful for promoting the osteogeneicity through the precise fabrication of patient-specific bone grafts with porous structures, which could favor the ingrowth of neo-bone tissues, the lack of suitable biomaterials with appropriate printability is still an obstacle that needs to be addressed. Thermoplastic polymer incorporated with osteoconductive bioceramics was a suitable biomaterial regarding to its good printability, biocompatibility and biodegradability. Unfortunately, the hydrophobic nature of synthetic polymers failed to form stable interfacial interactions with hydrophilic bioceramics, and hence restricted its uses in the application of bone tissue engineering. Thus, the aim of this study was to assess the reinforcement effect of polydopamine on the interfacial interaction between the thermoplastic polymer/bioceramic composite. The mechanical strength, hydrophilicity, and degradability of the composite porous scaffolds fabricated by a fused deposition modeling (FDM) based 3D printer were assessed. Moreover, the proliferation and differentiation of mesenchymal stem cells cultured on the scaffolds were examined. The results revealed that the compressive modulus of the polydopamine-incorporated composite scaffolds was strengthened by 67-130% compared to the unmodified composite scaffold. Additionally, results obtained from in vitro cell culture experiments indicated that the presence of polydopamine could also favor the proliferation, alkaline phosphatase activity, and calcium deposition of mesenchymal stem cells. The proposed route could be considered as a candidate strategy for developing three-dimensional printable composite materials for applications of bone regeneration.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cause severe outbreak of coronavirus disease 2019 (COVID-19). Even though vaccination, the spread of SARS-CoV-2 is still continue. It is urgent to have a model that can efficiently evaluate potential therapeutic agents to counteract SARS-CoV-2 infection. Iron is an essential molecule for maintaining homeostasis. Supplement of iron significantly to affect virus infection. But the detailed mechanisms of iron on regulating SARS-CoV-2 infection are still unveiled. The three-dimensional (3D) model is a promising system for drug screening and disease progression analysis. Organoid is a typical 3D culture system that recapitulates genetic characteristics and phenotypic features of organs within body. Vasculature is prevalent for all various organs or tumors in the body which transport nutrients, oxygen and metabolites to maintain cellular homeostasis. Thus, we have established a 3D model of vascularized organoid to evaluate the effects of iron on infectivity of SARS-CoV-2 pseudovirus to provide the novel therapeutic strategy in coping SARS-CoV-2 infection.