Bio-medical materials and engineering最新文献

Background: Myocardial infarction leads to myocardial necrosis, and cardiomyocytes are non-renewable. Fatty acid-containing cardiomyocyte maturation medium promotes maturation of stem cell-derived cardiomyocytes.

Objective: To study the effect palmitic acid on maturation of cardiomyocytes derived from human embryonic stem cells (hESCs) to optimize differentiation for potential treatment of myocardial infarction by hESCs.

Methods: hESCs were differentiated into cardiomyocytes using standard chemically defined medium 3 (CDM3). Up to day 20 of differentiation, 200 Mm palmitic acid were added, and then the culture was continued for another 8 days to mimic the environment in which human cardiomyocytes mainly use fatty acids as the main energy source. Light microscopy, transmission electron microscopy, immunofluorescence, reverse transcription-polymerase chain reaction, and cellular ATP assays, were carried out to analyze the expression of relevant cardiomyocyte-related genes, cell morphology, metabolism levels, and other indicators cardiomyocyte maturity.

Results: Cardiomyocytes derived from hESCs under exogenous palmitic acid had an elongated pike shape and a more regular arrangement. Sarcomere stripes were clear, and the cells color was clearly visible. The cell perimeter and elongation rate were also increased. Myogenic fibers were abundant, myofibrillar z-lines were regularly, the numbers of mitochondria and mitochondrial cristae were higher, more myofilaments were observed, and the structure of round-like discs was occasionally seen. Expression of mature cardiomyocyte-associated genes TNNT2, MYL2 and MYH6, and cardiomyocyte-associated genes KCNJ4, RYR2,and PPARα, was upregulated (p < 0.05). Expression of MYH7, MYL7, KCND2, KCND3, GJA1 and TNNI1 genes was unaffected (p > 0.05). Expression of mature cardiomyocyte-associated sarcomere protein MYL2 was significantly increased (p < 0.05), MYH7 protein expression was unaffected (p > 0.05). hESC-derived cardiomyocytes exposed to exogenous palmitic acid produced more ATP per unit time (p < 0.05).

Conclusion: Exogenous palmitic acid induced more mature hESC-CMs in terms of the cellular architecture, expression of cardiomyocyte maturation genes adnprotein, and metabolism.

Background: Restoration of the abdominal wall defects due to herniation or other complications represents a challenging task of the reconstructive surgery. Synthetic grafts or crosslinked animal-derived grafts, are utilized, followed by significant adverse reactions.

Objective: This study aimed to evaluate primarily the production of a decellularized abdominal wall scaffold and secondly its biocompatibility upon transplantation in an animal model.

Methods: Full-thickness abdominal wall samples were harvested from Wistar Rats and then decellularized utilizing a three-cycle process. To evaluate the decellularization efficacy, histological, biochemical and biomechanical analyses were performed. The biocompatibility assessment involved the implantation of the produced scaffolds to Sprague Dawley rats. The grafts remained for a total period of 4 weeks, followed by immunohistochemistry for the detection of CD11b+, CD4+ and CD8+ cells.

Results: Histological, biochemical and biomechanical results, indicated the production of compatible acellular full-thickness abdominal wall samples. After 4 weeks of implantation, a minor presence of immunity cells was observed.

Conclusion: The data of this study indicated the successful production of a full-thickness abdominal wall scaffold. Biologically derived full-thickness abdominal wall scaffolds may have greater potential in restoration of the abdominal wall defects, bringing them one step closer to their clinical utility.

Background: Polylactic acid (PLA) has been extensively used in tissue engineering. However, poor mechanical properties and low cell affinity have limited its pertinence in load bearing bone tissue regeneration (BTR) devices.

Objective: Augmenting PLA with β-Tricalcium Phosphate (β-TCP), a calcium phosphate-based ceramic, could potentially improve its mechanical properties and enhance its osteogenic potential.

Methods: Gels of PLA and β-TCP were prepared of different % w/w ratios through polymer dissolution in acetone, after which polymer-ceramic membranes were synthesized using the gel casting workflow and subjected to characterization.

Results: Gel-cast polymer-ceramic constructs were associated with significantly higher osteogenic capacity and calcium deposition in differentiated osteoblasts compared to pure polymer counterparts. Immunocytochemistry revealed cell spreading over the gel-cast membrane surfaces, characterized by trapezoidal morphology, distinct rounded nuclei, and well-aligned actin filaments. However, groups with higher ceramic loading expressed significantly higher levels of osteogenic markers relative to pure PLA membranes. Rule of mixtures and finite element models indicated an increase in theoretical mechanical strength with an increase in β-TCP concentration.

Conclusion: This study potentiates the use of PLA/β-TCP composites in load bearing BTR applications and the ability to be used as customized patient-specific shape memory membranes in guided bone regeneration.

Background: Diabetes is an emerging health issue on a global scale, with increasing prevalence rates reported in many countries. Many mechanisms are proposed for diabetic nephropathy, with oxidative stress being the most significant. The effectiveness of gold nanoparticles (AuNPs) in the attenuation of nephropathy and oxidative stress in diabetic mice was assessed in this study.

Objective: The aim of this study is to synthesize AuNPs and assess their protective effect towards diabetic nephropathy by inhibition of oxidative stress.

Methods: The aqueous extract of Allium sativum was employed to synthesize AuNPs. The prepared AuNPs were characterized using a variety of microscopic and spectroscopic techniques. In-vitro studies were conducted using mice. Streptozotocin (STZ) was employed to induce diabetes in rodents. After 7 days of administration of STZ, anesthesia was given to all animals and blood was collected for the assessment of creatinine and Blood Urea Nitrogen (BUN) levels. Later, kidney tissue was removed at 4 °C and changes in pathology and oxidative stress were assessed.

Results: Nephropathy was confirmed in diabetic mice by the changes in the pathology of kidney tissue along with significant rise in the plasma levels of BUN and creatinine. Additionally, the peroxidation of lipids, formation of Reactive Oxygen Species (ROS), oxidation of glutathione (GSH), concentration of carbonyl protein was also increased in the tissue of kidney of diabetic mice. Oxidative stress in kidney tissue and changes in the pathology of diabetic mice were inhibited significantly (p < 0.05) with the treatment of AuNPs.

Conclusion: This study revealed the protective effects of AuNPs over diabetic nephropathy by inhibiting the pathway of oxidative stress. Since, the prepared AuNPs showed improvement over complications of diabetes, they may be believed as a potential gratuitous treatment next to other drugs for reducing blood glucose.

Background: Nanomaterials have applications in traditional Chinese medicine in the fields of medical equipment manufacturing, targeted transportation, and drug synergistic therapy.

Objective: The research aims to discuss the performance and performance of zinc-iron-based nanomaterials in medical drug delivery and synergistic drug therapy.

Methods: Using Prussian materials as precursors, magnetic zinc-iron nanomaterials were prepared by ZnCl₂ and K₃[Fe (CN)₆]. Moreover, the morphology and composition of the material were analyzed.

Results: X-ray analysis was conducted on the prepared Zn₃[Fe (CN)₆]₂·xH₂O nanomaterials, and their purity met the design requirements. At the same time, drug loading analysis was conducted on Zn₃[Fe(CN)₆]₂·xH₂O, and the release of capsaicin reached 86.3% under a certain phosphate buffer solution. Meanwhile, Zn₃[Fe (CN)₆]₂·xH2O loaded tetracycline could release up to 90% in phosphate buffer solution. Antibacterial tests were conducted on self-made Zn₃[Fe(CN)₆]₂·xH₂O samples and ZnFe₂O₄/ZnO. The Zn₃[Fe(CN)₆]₂·xH₂O samples showed a more significant inhibitory effect on cancer cells after loading with capsaicin.

Conclusion: The zinc-iron-based nanomaterials prepared by the research have excellent performance in drug loading and safety, indicating their significant potential for development in the medical field.

Background: Mesenchymal stem cells-derived exosomes, crucial in regenerative medicine, have been explored for their potential for the functional modification of bone scaffolds.

Objective: To design a functionally modified biomimetic nanohydroxyapatite using exosomes and explore its effects on bone regeneration.

Methods: A biomimetic nanohydroxyapatite (named as tHA) was fabricated as previous methods using a polydopamine (pDA) structure as a template, and exosomes (Exo) derived from periodontal ligament stem cells (PDLSCs) were used to functionally modify the tHA scaffold material through pDA. The effects of functional composite scaffold (tHA-Exo) on cells proliferation and osteogenic differentiation were investigated. Furthermore, their effect on bone regeneration was also evaluated in vivo.

Results: Exosomes can be loaded onto the tHA via pDA and the tHA-Exo releases exosomes in a sustained and stable manner. tHA-Exo showed improved cytocompatibility compared to controls. Additionally, tHA-Exo significantly enhanced the proliferation and osteogenic differentiation of PDLSCs. More importantly, animal experiments have shown that tHA-Exo could dramatically promote bone regeneration.

Conclusion: The tHA nanoparticles, functionally modified by the PDLSCs-Exo through pDA, significantly promoted bone regeneration by improving its cytocompatibility and osteogenic potential, which could serve as a promising material for promoting bone regeneration.

Background: Percutaneous radiofrequency ablation (RFA) is a common method for treating liver cancer. Compared to other treatment modalities, RFA has a higher local tumor recurrence rate due to incomplete ablation. On the other hand, to ensure complete tumor removal, multiple ablations may be necessary, but this can lead to excessive thermal damage. Therefore, improving the precision of the ablation margin control is crucial.

Objective: This study aims to investigate an algorithm-controlled ablation mode that can precisely control the tumor treatment margins. This mode uses temperature and impedance as feedback parameters to adaptively adjust the RF power output, ensuring both effective tumor ablation and enhanced safety.

Methods: The study conducted finite element analyses and ex-vivo bovine liver experiments comparing traditional constant power ablation and the algorithm-controlled ablation mode. Simulations primarily analyzed the temperature changes and ablation area in biological tissue, assessing the effectiveness of the two ablation modes. In the ex-vivo bovine liver experiments, temperature and impedance were monitored in real-time to validate the feasibility of the algorithmic ablation mode.

Results: The findings indicate that the algorithm-controlled ablation mode effectively controls the rise in tissue impedance, preventing carbonization and charring. For ablation diameters of 10 mm and 20 mm, it precisely maintained the boundary temperatures within the range of 50-60°C, ensuring effective damage at the ablation margins while avoiding excessive damage to normal tissue.

Conclusion: This study developed an adaptive radiofrequency ablation algorithm for treating liver cancer, using temperature and impedance as feedback parameters. Preliminary results from finite element analysis and ex-vivo bovine liver experiments suggest that for small tumors with diameters of 10 mm and 20 mm, this algorithm may provide more precise control of the ablation zone, improving efficiency and safety compared to traditional constant power ablation.

Background: In sports, especially high-intensity and high-risk activities, the meniscus is easily damaged. For patients with meniscus injuries, it is necessary to repair or replace the patient's meniscus. However, as age increases, the human meniscus tissue gradually forms and cannot be repaired through its own meniscus. Therefore, it is necessary to maintain the patient's movement function through meniscus support materials.

Objective: Traditional meniscus support materials have poor mechanical properties and poor biocompatibility. In response to this issue, this study designed a meniscus scaffold made of silk short fibers, silk fibroin, and wool protein.

Methods: Through electrospinning and freeze-drying techniques, the material was processed to obtain a silk short fiber meniscus with a biomimetic structure.

Results: Through experiments, the surface morphology, hydrophobicity, porosity, secondary structure, thermal stability, water absorption swelling, and MP of MCS made of SSF biomimetic materials were characterized.

Conclusion: The experimental results show that the manufactured silk short fiber meniscus has good compressive performance, thermal stability, and water absorption and swelling properties, and it also exhibits good biocompatibility.

Background: Titanium (Ti) and polyether ether ketone (PEEK) interbody fusion cages cause postoperative stress shielding problems. The porous cage design is one of the solutions advanced to mitigate this problem.

Objective: Exploring the mitigation of stress shielding with a porous interbody fusion cage after surgery for idiopathic scoliosis.

Methods: The porous interbody fusion cage was constructed based on the multiscale topology optimisation method, and the postoperative lumbar spine models implanted with it. The porous Ti and PEEK fusion cages were evaluated under physiological conditions to investigate their mechanical properties.

Results: The volume of the porous fusion cage was reduced by 52.57%, and the stress was increased by 242.76% and 252.46% compared with the Ti and PEEK fusion cage; the modulus of elasticity of the porous fusion cage was reduced by 76.85%, and the strain was increased by 131.40%∼686.51% compared with the Ti cage; the porous fusion cage increased L3 cortical bone stress by 13.36% and 13.52% and cancellous bone by 82.93% and 76.72%, respectively, compared with the original interbody fusion cages.

Conclusion: The porous interbody fusion cage has a much more lightweight design which facilitates growth of bone tissue. However, a frame structure should be constructed to minimize issues with stress peaks and localised stress concentrations. It also has a significantly lower stiffness which helps alleviate vertebral stress shielding, further fostering bone growth. The porous fusion cage thus meets the clinical requirements for better fusion outcomes.

Background: The preservation period afforded by cold storage of cells is short. However, the use of rare gases for cold storage as a means of extending the period of preservation would be highly beneficial.

Objective: To examine the effect of temperature on the protective effect of cold storage of cells using pressurized dissolution of xenon gas, with particular focus on the inhibition of substance transport by viscosity.

Methods: Human dermal fibroblast monolayers incubated in a culture dish for 48 h were used as a test sample, with culture medium used as a preservation solution. Samples were placed into a pressure-resistant vessel, which was pressurized with xenon gas at 0 or 0.5 MPa, and cells were stored at 0 to 5°C for 18 h. Cell activity was evaluated by tetrazolium salt assay. The viscosity of the medium under pressurization at each storage temperature was estimated.

Results: The maximum protective effect against cell damage of cold storage with pressurized dissolution of xenon gas was observed at 4°C. An increase in estimated viscosity by pressurization was correlated with increased cell activity at 4°C.

Conclusion: Analysis of the temperature dependence of the protective effect against cell damage of cold storage with pressurized dissolution of xenon gas revealed that the most effective temperature is 4°C. The data also suggest that increased viscosity due to pressurization plays a role in the protective effect.