Challenges and Pitfalls of Research Designs Involving Magnesium-Based Biomaterials: An Overview

Magnesium-based biomaterials hold remarkable promise for various clinical applications, offering advantages such as reduced stress-shielding and enhanced bone strengthening and vascular remodeling compared to traditional materials. However, ensuring the quality of preclinical research is crucial for the development of these implants. To achieve implant success, an understanding of the cellular responses post-implantation, proper model selection, and good study design are crucial. There are several challenges to reaching a safe and effective translation of laboratory findings into clinical practice. The utilization of Mg-based biomedical devices eliminates the need for biomaterial removal surgery post-healing and mitigates adverse effects associated with permanent biomaterial implantation. However, the high corrosion rate of Mg-based implants poses challenges such as unexpected degradation, structural failure, hydrogen evolution, alkalization, and cytotoxicity. The biocompatibility and degradability of materials based on magnesium have been studied by many researchers in vitro; however, evaluations addressing the impact of the material in vivo still need to be improved. Several animal models, including rats, rabbits, dogs, and pigs, have been explored to assess the potential of magnesium-based materials. Moreover, strategies such as alloying and coating have been identified to enhance the degradation rate of magnesium-based materials in vivo to transform these challenges into opportunities. This review aims to explore the utilization of Mg implants across various biomedical applications within cellular (in vitro) and animal (in vivo) models.

Bioactive glass 1393 promotes angiogenesis and accelerates wound healing through ROS/P53/MMP9 signaling pathway

Compared to bioactive glass 45S5, bioactive glass 1393 has shown greater potential in activating tissue cells and promoting angiogenesis for bone repair. Nevertheless, the effect of bioactive glass 1393 in the context of wound healing remains extensively unexplored, and its mechanism in wound healing remains unclear. Considering that angiogenesis is a critical stage in wound healing, we hypothesize that bioactive glass 1393 may facilitate wound healing through the stimulation of angiogenesis. To validate this hypothesis and further explore the mechanisms underlying its pro-angiogenic effects, we investigated the impact of bioactive glass 1393 on wound healing angiogenesis through both in vivo and in vitro studies. The research demonstrated that bioactive glass 1393 accelerated wound healing by promoting the formation of granulation, deposition of collagen, and angiogenesis. The results of Western blot analysis and immunofluorescence staining revealed that bioactive glass 1393 up-regulated the expression of angiogenesis-related factors. Additionally, bioactive glass 1393 inhibited the expression of ROS and P53 to promote angiogenesis. Furthermore, bioactive glass 1393 stimulated angiogenesis through the P53 signaling pathway, as evidenced by P53 activation assays. Collectively, these findings indicate that bioactive glass 1393 accelerates wound healing by promoting angiogenesis via the ROS/P53/MMP9 signaling pathway.

Numerical analysis of scaffold degradation in cryogenic environment: impact of cell migration and cell apoptosis

The analysis of degradation in the presence of cell death and migration is a critical aspect of research in various biological fields, such as tissue engineering, regenerative medicine, and disease pathology. In present study, numerical study of degradation of scaffold were performed in present of cells, cell apoptosis and cell migration. A poly electrolyte complex (PEC) silk fibroin scaffold was used for degradation study. Degradation study in the presence of cells and migration were performed at fixed pH concentration 7.2. Similarly, degradation study of scaffold were performed at different pH cell apoptosis. A transient analysis of scaffold was evaluated in COMSOL 5.5 in presence of cryogenic temperature at different temperature gradient. The parameters; temperature, stress, strain tensor and deformation gradient associated with the degradation of polyelectrolyte complex scaffold were evaluated. Result shows that in both geometries minimum temperature had been achieved as 230.051 K at point P4 in series view and parallel view and at a point P3 for cell migration study for -5 k min-1and -1 k min-1, respectively. The maximum stress had been generated for 5.57 × 107N m-2for the temperature gradient of -2 K min-1at T cycle in the case of cell migration study. In contrast in series view the maximum stress 2.9 × 107 N m-2were observed at P4 which was higher as compare to P3. Similarly, for a parallel view, maximum stress (3.93 × 107 N m-2) was obtained for point P3. It had been observed that the maximum strain tensor 5.21 × 10-3, 5.15 × 10-3and 5.26 × 10-3was generated in series view at 230 k on a point P3 for - 1, -2 and -5 K min-1, respectively. Similarly, the maximum strain tensor 8.16 × 10-3, 8.09 × 10-3and 8.09 × 10-3was generated in parallel view at 230 k on a point P3 for -1, -2 and -5 K min-1, respectively. In the presence of cells, at a point P4 for temperature gradient of -1 and -2 K min-1, it had been closed to the scaffold wall, which had a different temperature profile than the point P3 and scaffold comes to the contact with the cells. The analysis of PEC scaffold degradation in the presence of cells, including cell apoptosis and migration, offers significant insights into the relationship between scaffold properties, cell behaviour, and tissue regeneration.

Effects of sericin and egg white on the inflammation of damaged skin in mice

Sericin and egg white (EW) have shown the ability to promote wound healing. However, there have been insufficient studies regarding the effects of sericin and EW mixtures on wound healing. This study aimed to investigate the effects of a hybrid sericin and EW solution on wound repair and inflammation-related indicators in mouse skin. In this work, sericin with a low molecular weight was first mixed with homogeneous EW to prepare a hybrid wound dressing. Histology evaluation, the expression of C-reactive protein (CRP) and inflammatory cytokines in mice were tested to determine the effects of this dressing on skin injuries in mice. The results showed that sericin and the hybrid solution of sericin and EW effectively promoted wound healing in mouse skin. The wound recovery rates of mice 12 days after treatment with a medium dose of sericin (0.2 g ml^-1) and the same dosage of sericin with added EW were 1.32 and 1.65 times that of mice treated with phosphate buffer saline as a control, respectively. In addition, the mixture solution was more effective in wound healing than sericin alone. Sericin with EW significantly reduced the expression of CRP and inflammatory cytokines in mice during wound healing. A sericin and EW hybrid solution can effectively shorten the time needed for wound healing and reduce inflammation-related indicators in mice, making it a promising candidate for wound dressing.

Biomimetic injectable hydrogel based on silk fibroin/hyaluronic acid embedded with methylprednisolone for cartilage regeneration

Articular cartilage injury is characterized by limited self-repair capacity due to the shortage of blood vessels, lymphatics, and nerves. Hence, this study aims to exploit a classic injectable hydrogel platform that can restore the cartilage defects with minimally invasive surgery, which is similar to the natural extracellular microenvironment, and highly porous network for cell adhesion and proliferation. In this study, an injectable scaffold system comprised of silk fibroin (SF) and hyaluronic acid (HA) was developed to adapt the above requirements. Besides, methylprednisolone (MP) was encapsulated by SF/HA scaffold for alleviating inflammation. The SF/HA hydrogel scaffold was prepared by chemical cross-linking between the lysine residues of SF via Schiff base formation, and pore diameter of the obtained hydrogels was 100.47 ± 32.09 µm. The highly porous nature of hydrogel could further benefit the soft tissue regeneration. Compared with HA-free hydrogels, SF/HA hydrogel showed more controlled release on MP. In ovo experiment of chick embryo chorioallantoic membrane (CAM) demonstrated that SF/HA hydrogels not altered the angiogenesis and formation of blood vessels, thus making it suitable for cartilage regeneration. Furthermore, in vivo gel formation was validated in mice model, suggesting in situ gel formation of SF/HA hydrogels. More importantly, SF/HA hydrogels exhibited the controlled biodegradation. Overall, SF/HA hydrogels provide further insights to the preparation of effective scaffold for tissue regeneration and pave the way to improve the articular cartilage injury treatment.

Antheraea pernyi silk fibroin-coated adenovirus as a VEGF165-Ang-1 dual gene delivery vector

Vascularization is a key challenge in the regeneration of tissues containing blood vessels. In this study, spermine was used for cationic modification of Antheraea pernyi silk fibroin (ASF) to synthesize cationized ASF (CASF). CASF/Ad complexes prepared by coating adenovirus (Ad) with CASF were used as delivery vectors for vascular endothelial growth factor 165 and angiopoietin-1 dual genes. The results showed that the zeta potential of the Ad was reversed from −7.75 mV to approximately +8.40 mV after CASF coating, and the sizes of the CASF/Ad complexes were 200 to 290 nm. Furthermore, human umbilical vein endothelial cells HUVECs were cocultured and infected with CASF/Ad in vitro. The results of confocal laser scanning microscopy, flow cytometry and CCK-8 assay showed that coating Ad with CASF at concentration of 20 and 50 µg/mL not only reduced the cytotoxicity of naked Ad, but also significantly promoted cell proliferation. Therefore, the CASF/Ad complexes could be beneficial to reduce the dosage of Ad and the potential toxicity risk of high doses of Ad in vivo, which has the potential of application to promote vascular network regeneration.

Fibroblast Derived Skin Wound Healing Modeling on Chip under the Influence of Micro-Capillary Shear Stress

Fibroblast cell migration plays a crucial role in the wound-healing process. Hence, its quantitative investigation is important to understand the mechanism of the wound-healing process. The dynamic nature of the wound-healing process can be easily implemented using a microfluidic-based wound-healing assay. This work presented the use of a microfluidics device to simulate traumatic wounds on fibroblast cell monolayers by utilizing trypsin flow and PDMS barrier. In this study, a microfluidic chip with a transparent silk film is reported. The placement of film provides 3D cell culture conditions that mimic a 3D extracellular matrix (ECM) like environment and allows real-time monitoring of cells. A numerical study was conducted to evaluate the influence of dynamic medium-induced shear stress on the base and wall of the microchannel. This could facilitate the optimization of the inlet flow conditions of the media in the channel. At the same time, it could help in identifying stress spots in the channel. The scaffolds were placed in those spots for evaluating the influence of shear forces on the migratory behavior of fibroblast cells. The in vitro microfluidic assembly was then evaluated for cell migration under the influence of external shear forces during the wound-healing phenomena. A faster wound healing was obtained at the end of 24 h of the creation of the wound in the presence of optimal shear stress. On increasing the shear stress beyond a threshold limit, it dissociates fibroblast cells from the surface of the substrate, thereby decelerating the wound-healing process. The above phenomena were transformed in both coplanar microfluidics surfaces (by realizing in the multichannel interlinked model) and transitional microfluidics channels (by realizing in the sandwich model).