Fine hand movements require the synergistic contraction of intrinsic and extrinsic muscles to achieve them. In this paper, a Finite Element Digital Human Hand Model (FE-DHHM) containing solid tendons ...and ligaments and driven by the Muscle-Tendon Junction (MTJ) displacements of FDS, FDP and ED measured by ultrasound imaging was developed. The synergistic contraction of these muscles during the finger flexion movements was analyzed by simulating five sets of finger flexion movements. The results showed that the FDS and FDP contracted together to provide power during the flexion movements, while the ED acted as an antagonist. The peak stresses of the FDS, FDP and ED were all at the joints. In the flexion without resistance, the FDS provided the main driving force, and the FDS and FDP alternated in a "plateau" of muscle force. In the flexion with resistance, the muscle forces of FDS, FDP, and ED were all positively correlated with fingertip forces. The FDS still provided the main driving force, but the stress maxima occurred in the FDP at the DIP joint.
Fine hand movements require the synergistic contraction of intrinsic and extrinsic muscles to achieve them. In this paper, a Finite Element Digital Human Hand Model (FE-DHHM) containing solid tendons ...and ligaments and driven by the Muscle-Tendon Junction (MTJ) displacements of FDS, FDP and ED measured by ultrasound imaging was developed. The synergistic contraction of these muscles during the finger flexion movements was analyzed by simulating five sets of finger flexion movements. The results showed that the FDS and FDP contracted together to provide power during the flexion movements, while the ED acted as an antagonist. The peak stresses of the FDS, FDP and ED were all at the joints. In the flexion without resistance, the FDS provided the main driving force, and the FDS and FDP alternated in a "plateau" of muscle force. In the flexion with resistance, the muscle forces of FDS, FDP, and ED were all positively correlated with fingertip forces. The FDS still provided the main driving force, but the stress maxima occurred in the FDP at the DIP joint.
In order to find a convenient and stable way to trace human skin fibroblasts (HSFs) in three-dimensional tissue engineering scaffolds for a long time, in this experiment, Graphene Oxide Quantum Dots ...(GOQDs), Amino Graphene Quantum Dots (AGQDs) and Carboxyl Graphene Quantum Dots (CGQDs) were used as the material source for labeling HSFs. Exploring the possibility of using it as a long-term tracer of HSFs in three-dimensional tissue engineering scaffolds, the contents of the experiment are as follows: the HSFs were cultured in a cell-culture medium composed of three kinds of Graphene Quantum Dots for 24 h, respectively; (1) using Cell Counting Kit 8 (CCK8), Transwell migration chamber and Phalloidin-iFlior 488 to detect the effect of Graphene Quantum Dots on the biocompatibility of HSFs; (2) using a living cell workstation to detect the fluorescence labeling results of three kinds of Graphene Quantum Dots on HSFs, and testing the fluorescence attenuation of HSFs for 7 days; (3) the HSFs labeled with Graphene Quantum Dots were inoculated on the three-dimensional chitosan demethylcellulose sodium scaffold, and the living cell workstation was used to detect the spatial distribution of the HSFs on the three-dimensional scaffold through the fluorescence properties of the HSFs.. Experimental results: (1) the results of CCK8, Transwell migration, and FITC-Phalloidin cytoskeleton test showed that the three kinds of Graphene Quantum Dots had no effect on the biological properties of HSFs (p < 0.05); (2) the results of the fluorescence labeling experiment showed that only AGQDs could make HSFs fluorescent, and cells showed orange−red fluorescence; (3) the results of long-range tracing of HSFs which were labeled by with AGQDs showed that the fluorescence life of the HSFs were as long as 7 days; (4) The spatial distribution of HSFs can be detected on the three-dimensional scaffold based on their fluorescence properties, and the detection time can be up to 7 days.
As tissue regeneration material, electrospun fibers can mimic the microscale and nanoscale structure of the natural extracellular matrix (ECM), which provides a basis for cell growth and achieves ...organic integration with surrounding tissues. At present, the challenge for researchers is to develop a bionic scaffold for the regeneration of the wound area. In this paper, polyurethane (PU) is a working basis for the subsequent construction of tissue-engineered skin. poly(L-lactide-co-caprolactone) (PLCL)/carboxymethyl chitosan (CMCS) composite fibers were prepared via electrospinning and cross-linked by glutaraldehyde. The effect of CMCS content on the surface morphology, mechanical properties, hydrophilicity, swelling degree, and cytocompatibility were explored, aiming to assess the possibility of composite scaffolds for tissue engineering applications. The results showed that randomly arranged electrospun fibers presented a smooth surface. All scaffolds exhibited sufficient tensile strength (5.30-5.60 MPa), Young's modulus (2.62-4.29 MPa), and swelling degree for wound treatment. The addition of CMCS improved the hydrophilicity and cytocompatibility of the scaffolds.
•The Bama minipig can be a model to study pathological scar.•Pressure improves wound healing and alleviates scar formation.•Pressure inhibits IGF-1/IGF-1R signal pathway.•Pressure suppresses collagen ...expression.
Pressure therapy has been widely used in clinical practice for the prevention or treatment of hypertrophic scars resulted from aberrations in wound healing. However, the precise molecular mechanisms of this process are only partially understood. In the present study, we established a Bama minipig model to observe the effect of pressure intervention on wound healing and scar formation. Transcriptome sequencing was performed to analyze the gene expression profiles in the injured and pressure-treated tissues. Furthermore, expression of the critical factors associated with IGF-1/IGF-1R pathways including PI3K/AKT and MEK/ERK and collagens were further analyzed by quantitative polymerase chain reaction (q-PCR) and Western blot. We observed that the mRNA expression of IGF-1 and IGF-1R were down-regulated in the pressure treated groups. Following pressure intervention, the trend in expression of PI3K/AKT decreased, whereas that of MEK/ERK expression increased, when quantified by q-PCR. Moreover, the level of PI3K protein expression decreased significantly after pressure treatment for one month but there was no significant difference in AKT protein expression. Interestingly, the trend in MEK/ERK protein expression was opposite to that indicated by q-PCR analysis. Furthermore, collagen I and III mRNA clearly declined after one month pressure treatment. Taken together, these results indicated that pressure intervention alleviated scar formation may via inhibiting the IGF-1/IGF-1R signaling pathway and collagen expression in the Bama minipig model.
Three-dimensional (3D) hydrogel models play a crucial role in tissue engineering for promoting tissue regeneration. A biomimetic microchannel network system in the 3D hydrogel model is necessary for ...optimal cellular function. This report describes the preparation of a biomimetic hydrogel scaffold with an internal microchannel network, using electrospinning techniques and the sacrificial template method for 3D cell culture. Microchannels and cavities were created within the gelatin methacryloyl (GelMA) hydrogel by sacrificing polyvinyl alcohol (PVA) electrospun fibers (>10 µm), resulting in the creation of microvessel-like channels. Mechanical characterizations, swelling properties, and biodegradation analysis were conducted to investigate the feasibility of a biomimetic microchannel network hydrogel scaffold for 3D cell culture applications. Compared to pure GelMA hydrogel, the hydrogel with microchannels promoted cell proliferation, adhesion, and endothelial tube formation. Moreover, the results confirmed that the biomimetic microchannel network scaffold had a major impact on the distribution and arrangement of human umbilical vein endothelial cells (HUVECs) and can enable the formation of artificial microvasculature by the culture of HUVECs and cell media perfusion.
•PU/PLCL composite membranes with different proportions were prepared via electrospinning.•Bonding joints in PU/PLCL composite electrospun membranes could result in a transfer of force on the ...fibers.•The prepared PU/PLCL composite electrospun membranes with a PLCL content of 50% exhibited suitable mechanical properties.•The prepared PU/PLCL composite electrospun membranes exhibited good biocompatibility.
Skin tissue engineering with considerable skin regeneration capability is an urgent need for the wound site. The current challenge for researchers is to develop a bionic scaffold that imitates the extracellular matrix for the regeneration of the damaged regions. In our study, poly(L-lactide-co-caprolactone) (PLCL) was blended with polyurethane (PU) to obtain nanofibrous scaffolds via electrospinning. The electrospun fibers with 50% PLCL content had a certain number of intersections and jointing points, and exhibited significantly enhanced mechanical properties combined with suitable porosity. Moreover, cell activities demonstrated that PU/PLCL membranes had significantly biological advantages in enhanced growth of human skin fibroblasts with spreading morphology compared with PU membranes, indicating good cytocompatibility of composite scaffolds. These findings proved that PU/PLCL electrospun membranes have great potential in applications of skin tissue engineering.
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Hyperplastic scar is a common fibrotic disease that may ultimately lead to severe dysfunction and deformity, causing physical and psychological distress. Therefore, we aim to evaluate the effect of ...the mechanical microenvironment of scar substrates on the morphology of human fibroblasts (HFbs). The micro-modular fabrication technique was used to design a new cross-groove topology and to construct four elastic substrates with the stiffness of 19.3 kPa and 90.1 kPa coupled with parallel groove and cross groove, respectively, to simulate the mechanical microenvironment of skin wounds and scar tissues. The morphological changes in HFbs in different substrates were observed, and the changes in the cell-long axis length, area, and the angle between cell-long axis and grooves were recorded. Immunofluorescence staining was performed to observe the distribution of microfilaments. The results indicated that substrate stiffness and topography affected the morphology of HFbs. The cells were elongated in parallel grooves as well as in the area where cross grooves restricted groove length, the cell length was restricted, and the angle between the long axis and the groove was increased. The topography exerted no significant effect on the cell area, but the cell area increased with increasing the stiffness. The parallel groove promoted the expression of the F-actin to a certain extent, and the fluorescence intensity of F-actin decreased with increasing the stiffness. Studying the effect of the mechanical microenvironment of substrates on HFb morphology is of great importance for understanding the mechanisms of scar formation and prevention.
In stent restenosis (ISR) is one of the major complications after stent implantation. Thus, there is a growing interest in identifying a biomarker for the onset of ISR. High levels of serum ...homocysteine (Hcy) have been associated with the progression of cardiovascular disease. Therefore, the study was carried out to quantify the correlation between serum Hcy and ISR severity. Compared with coronary angiography (CAG), Hcy levels provided a significantly better clinical detection of ISR severity after PCI.
A total of 155 patients were recruited from Shanxi Bethune hospital, from 6 months to 2 years post PCI. Serum Hcy levels and postoperative angiography results were used to differentiate the patients into two experimental groups: ISR (>50% diametrical stenosis), and non-ISR. The non-ISR included two subgroups: intimal hyperplasia (10-50% diametrical stenosis), and recovery (<10% diametrical stenosis). In addition, a group of 80 healthy individuals was used as a negative control. The correlation between homocysteine level and ISR severity t was analyzed for all groups. In addition, the correlation between serum Hcy level and the severity of ISR in the experimental group was analyzed by the Pearson correlation test.
The serum Hcy level in the experimental group and control group was determined to be (20.21 ± 11.42) μmol/L and (15.11 ± 10.25) μmol/L respectively. The level of serum Hcy in the experimental group was significantly higher than in the control group (
-value of 2.385;
-value of 0.019). The serum Hcy level in the restenosis and the intimal hyperplasia group was (25.72 ± 13.71) μmol/L and (17.35 ± 7.70) μmol/L respectively. The serum Hcy level in the restenosis group was significantly higher than in the intimal hyperplasia group (
-value of 2.215;
-value of 0.033). The level of serum Hcy in the group without a plaque in the stent was (16.30 ± 6.08) μmol/L, whereas in the control group was (15.11 ± 10.25) μmol/L. The no plaque group had a slightly higher serum Hcy level than the control group (
-value of 0.634;
value of 0.528). All included patients were divided into four quartiles based on the serum Hcy concentration: quartile 1 (8.90-13.20 μmol/L), quartile 2 (13.30-16.45 μmol/L), quartile 3 (16.60-24.25 μmol/L) and quartile 4 (24.30-65.30 μ mol/L). The incidence of ISR was 5, 6.25, 7.5 and 15%, in the 1,2,3 and four quartiles respectively. The serum Hcy level in the experimental group was (20.21 ± 11.42) μmol/L, the severity of in-stent restenosis was (0.25 ± 0.31), (
value was 0.234;
value was 0.037), indicating a correlation between serum Hcy and the severity of restenosis (
< 0.05). Taking coronary angiography as the gold standard, a ROC curve analysis was performed on the serum Hcy levels for the experimental group. The area under the curve (AUC) was 0.718 (95%
0.585-0.854,
< 0.001), indicating that the serum Hcy concentration could predict ISR. On the ROC curve, the best critical value of serum Hcy concentration for predicting ISR was 20.05 μmol/L, with a sensitivity of 45% and specificity of 88.1%.
A positive correlation was observed between homocysteine and the severity of restenosis after PCI, The level of Hcy could serve as a predictive biomarker for the severity of ISR.
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