Bio-medical materials and engineering最新文献

BackgroundIn 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.ObjectiveTraditional 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.MethodsThrough electrospinning and freeze-drying techniques, the material was processed to obtain a silk short fiber meniscus with a biomimetic structure.ResultsThrough experiments, the surface morphology, hydrophobicity, porosity, secondary structure, thermal stability, water absorption swelling, and MP of MCS made of SSF biomimetic materials were characterized.ConclusionThe 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.

BackgroundThe impact of rotational angle between the femoral and tibial components is often overlooked in the 2D evaluation of varus/valgus stability after TKA with anterior-posterior knee X-rays. The rotation angle between the femoral and tibial components may influence the measured angle and distance between these components in 2D stress X-rays following TKA.ObjectiveThe purpose of this study was to assess the impact of the rotational angle between the femoral and tibial components on the evaluation of varus/valgus stability using stress X-rays following total knee arthroplasty (TKA).MethodsThis prospective study analyzed 48 consecutive rTKAs (three males, aged 68 ± 6.4 years; 45 females, aged 75 ± 5.9 years). Postoperative varus/valgus stress X-rays were taken at maximum manual stress during knee extension under anesthesia, and were analyzed three-dimensionally using a 2D-3D image matching technique with 3D bone and component models. The rotation angles of the components (CR angles) were assessed under conditions of no stress, valgus stress, and varus stress. Additionally, the varus/valgus angle (VV angle) between components was evaluated under the same conditions. Medial joint opening (MJO) and lateral joint opening (LJO) were also measured in both stressed and non-stressed states.ResultsThe CR angles under no stress, valgus stress, and varus stress were 9.9 ± 5.5°, 10.1 ± 6.2°, and 10.8 ± 5.1°, respectively. The VV angles under no stress, valgus stress, and varus stress were 3.6 ± 1.1°, 1.1 ± 1.4°, and 7.1 ± 1.9°, respectively. The MJO in the non-stress condition and under valgus stress were 0.0 ± 0.4 mm and 1.3 ± 1.0 mm, respectively. The LJO in the non-stress condition and under varus stress were 0.9 ± 0.9 mm and 2.9 ± 2.7 mm, respectively.ConclusionsThis prospective study revealed two key findings: (1) the CR angle in varus stress was significantly more externally rotated compared to the CR angle in the non-stress condition, and (2) no significant correlations were found between the rotational angle of the components and the VV angle, MJO, or LJO.

BackgroundPercutaneous 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.ObjectiveThis 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.MethodsThe 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.ResultsThe 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.ConclusionThis 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: Wound healing proceeds through a complex collaborative process. It has been shown that during the intermediate phase of the wound healing process, fibroblasts migrate into wound area and contract to contribute to the closure of the wound area. Moreover, previous studies have shown that fibroblast alignment was observed on the mature stage of wound scar. These studies clearly indicate that fibroblasts play a critical role in wound healing process, however, the whole mechanism of wound healing remains still unclear.

Objective: Fibroblasts are pre-aligned to evaluate the effect of cell alignment on cell migration rate.

Methods: The cell alignment was accomplished by PDMS microstamping with fibronectin and application of cyclic stretching. Wound was created by physical scratching and then the wound closure rate was measured.

Results: The pre-aligned cells perpendicular to the direction of scratched wound exhibited significantly higher migration rate, compared to non-aligned control cells. Moreover, pre-aligned cells with thick actin filaments by cyclic stretching migrated faster than those with less development of actin filament structures by microstamping.

Conclusion: The wound closure can be accelerated by the adequate alignment of fibroblasts as well as the development of actin filament structures.

Background: Urethral stricture (US) is a common condition that considerably affects patients' quality of life.

Objectives: This study aimed to explore the adoption value of the extracellular vesicle (EV)- small intestinal submucosa (SIS) complex in the repair of USs.

Methods: EVs were extracted from healthy male New Zealand white rabbits, and SIS was prepared using peracetic acid (PAA) oxidation and decellularization. The morphology and particle size of the prepared EV-SIS complex were evaluated using electron microscopy and qNano nanoparticle analyzer, and the labeled proteins of EVs were detected using Western blot method. EV-SIS the complex was implanted in a rabbit model of US, and urodynamic parameters were assessed.

Results: The EV-SIS complex displayed a full morphology, intact membrane structure, and uniform particle size. The protein concentration of EVs in the complex was approximately 0.351 µg/µL, with a yield of approximately 1.86 µg/10⁶ cells. The complex exhibited remarkable repair effects in the rabbit model of US, with bladder capacity, maximal urethral pressure, and minimal urethral pressure all markedly superior to those in the US group (P < 0.05).

Conclusion: The EV-SIS complex demonstrates potential clinical value in the repair of USs, improving urodynamic parameters, and offering a promising therapeutic option for patients with US.

Background: Dissociation is a special type of dislocation that is rarely seen in bipolar hemiarthroplasty.

Objective: To investigate the clinical and biomechanical causes of dissociative dislocation of acetabular cup components in the hips of patients after bipolar hemiarthroplasty (BHA).

Methods: BHA heads were divided into three groups according to their design. Cam-out and pull-out biomechanical tests were conducted to investigate the separation strengths of the BHA heads.

Results: Among the 1684 BHA surgeries performed, the revision surgery rate was 4% (68 hips) and dissociation rate was 0.8% (15 hips). According to the cam-out test result, the highest values in the parameters ultimate force (F_max) ultimate torque (T), vertical displacement at maximum force (δ_m), rotation at maximum force (ϕ_m), maximum principal strain (Ɛ_max), minimum principal strain (Ɛ_min), average normal strain (Ɛ_av), maximum shear strain (γ_max), uniaxial normal strain (Ɛ_un) were detected in Type 2 BHA head. The pull-out values of the implants were sufficient to prevent the distraction force that may occur on the implant due to manual traction applied to the hip dislocations. However, in closed reduction maneuvers, cam-out-shaped deformation forces may cause dissociation in Types 1 and 3, but not in Type 2 BHA heads. According to the pull-out test results, while high values were detected in the parameters Fmax and stiffness (k) in the Type 2 BHA head, δm and maximum force (E) parameters were found to be high in the Type 1 BHA head. In the cam-out test, a strong positive relationship was found between the thickness and width of the polyethylene locking ring and F_max, T, δ_m, ϕ_m, Ɛ_max, γ_max, Ɛ_un.

Conclusion: Better BHA head designs and polyethylene designs may help resolve the rare problem of dissociation, which almost always leads to resurgical procedures.

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.