Bio-medical materials and engineering最新文献

BackgroundAdult newt (9-month-old) has become an emerging research model to study complete regeneration of injured adult tendon. If younger newts exhibit tendon regeneration similar to adult ones, they can be used as an additional experimental model, assuring a high- throughput of experiments using genetic manipulation owing to shorter period of growing.ObjectiveTo examine mechanical properties and tissue structure of tendon in immature Iberian ribbed newt following complete transection.MethodsDigital flexor tendon of the middle finger of the left hindlimb in 4- and 6-month-old Iberian ribbed newt (4mo and 6mo, respectively) was transected. Regenerated tendon was mechanically tested at 6 and 12 weeks postoperatively. Collagen fiber structure was also observed using two-photon microscopy.ResultsIn both 4mo and 6mo newts, regenerated tendon at 6 weeks exhibited significantly lower tensile strength than corresponding normal tendons and had unorganized collagen structure. At 12 weeks, Regenerated tendon in both groups had the strength comparable to normal controls. Additionally, the collagen structure seemed more organized compared to that at 6 weeks and comparable to controls. These phenomena were essentially similar to those in adult newts.Conclusion4mo and 6mo newts can also be used as experimental models of adult tendon regeneration research.

BackgroundThe utilization of bioceramics for medical implants necessitates the incorporation of antibacterial properties to mitigate post-surgical inflammation of bone tissue.ObjectiveIn this research, Zn²⁺ ions were introduced as an antibacterial agent into carbonate-hydroxyapatite-based honeycomb Scaffold bioceramics (CHA/HCB), with varying doping concentrations, to investigate the impact of Zn²⁺ on the antibacterial activity of CHA/HCB against Staphylococcus aureus and Pseudomonas aeruginosa.MethodsCHA was synthesized from abalone shells through the co-precipitation method, followed by the fabrication of a CHA-based scaffold with HCB using the porogen leaching technique. Subsequently, the Zn ion doping process was executed through the ion exchange method, using concentrations of 0.05 M, 0.1 M, 0.15 M, and 0.2 M. The samples were characterized using XRF and antibacterial test.ResultsThe XRF results revealed that the Ca/P ratio of CHA/HCB was within the range of 1.48-1.85, indicating a declining trend with the introduction of Zn²⁺ as a dopant. Nevertheless, these results remained within acceptable ranges, ensuring compatibility with bone tissue. In terms of antibacterial activity, the measured inhibition zone diameters increased alongside the increase of Zn concentration. The zone diameters ranged from 14.3 to 22.0 mm against Staphylococcus aureus and 13.7 to 21.4 mm against Pseudomonas aeruginosa.ConclusionThe findings suggest that Zn doping in CHA/HCB bioceramics has a potential an antibacterial agent in CHA scaffolds as well as potential for practical applications, particularly in reducing the risk of postoperative infection in bone tissue implantation.

BackgroundMesenchymal stem cells-derived exosomes, crucial in regenerative medicine, have been explored for their potential for the functional modification of bone scaffolds.ObjectiveTo design a functionally modified biomimetic nanohydroxyapatite using exosomes and explore its effects on bone regeneration.MethodsA 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.ResultsExosomes 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.ConclusionThe 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.

BackgroundTitanium (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.ObjectiveExploring the mitigation of stress shielding with a porous interbody fusion cage after surgery for idiopathic scoliosis.MethodsThe 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.ResultsThe 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.ConclusionThe 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: Vessel segmentation is a critical aspect of medical image processing, often involving vessel enhancement as a preprocessing step. Existing vessel enhancement methods based on eigenvalues of Hessian matrix face challenges such as inconsistent parameter settings and suboptimal enhancement effects across different datasets.

Objective: This paper aims to introduce a novel vessel enhancement algorithm that overcomes the limitations of traditional methods by leveraging a multilayer perceptron to fit a vessel enhancement filter function using eigenvalues of Hessian matrix. The primary goal is to simplify parameter tuning while enhancing the effectiveness and generalizability of vessel enhancement.

Methods: The proposed algorithm utilizes eigenvalues of Hessian matrix as input for training the multilayer perceptron-based vessel enhancement filter function. The diameter of the largest blood vessel in the dataset is the only parameter to be set.

Results: Experiments were conducted on public datasets such as DRIVE, STARE, and IRCAD. Additionally, optimal parameter acquisition methods for traditional Frangi and Jerman filters are introduced and quantitatively compared with the novel approach. Performance metrics such as AUROC, AUPRC, and DSC show that the proposed algorithm outperforms traditional filters in enhancing vessel features.

Conclusion: The findings of this study highlight the superiority of the proposed vessel enhancement algorithm in comparison to traditional methods. By simplifying parameter settings, improving enhancement effects, and showcasing superior performance metrics, the algorithm offers a promising solution for enhancing vessel parts in medical image analysis applications.

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: The differences in bony alignment of the lower extremities during gait compared to standing remain unclear.

Objective: This study aimed to evaluate three-dimentional (3D) lower extremity alignment in healthy elderly individuals during the stance phase of gait and compare it with static standing alignment.

Methods: Thirty-four knees (9 females, 8 males; mean age 73.2 years) were assessed using single-plane X-ray fluoroscopy and a 3D to two-dimensional (2D) image matching technique. Alignment during stance phase and standing was evaluated in a world coordinate system, using the direction of gravity and frontal X-ray (aligned with the gait direction) as references.

Results: Compared to standing, the femur (3.5°), tibia (3.2°) and tibial joint line relative to the floor (3.3°) exhibited increased lateral inclination during stance phase (p < 0.01). In the transverse plane, the femur showed a significant increase in external rotation during stance phase (5.0°, p < 0.01) compared to standing, with no significant difference in tibial rotation.

Conclusion: Lower extremity alignment significantly differs between static standing and gait, making it challenging to accurately infer the alignment during gait from standing assessments. This approach offers a practical means for assessing functional lower extremity alignment, potentially improving clinical outcomes in realignment surgeries.

Background: Lung cancer is a leading cause of cancer-related deaths worldwide, making early diagnosis crucial for improving treatment success and survival rates. Traditional diagnostic methods, such as biopsy and manual CT image interpretation, are time-consuming and prone to variability, highlighting the need for more efficient and accurate tools. Advances in deep learning offer promising solutions by enabling faster and more objective medical image analysis.

Objective: This study aims to classify benign, malignant, and normal lung CT images using advanced deep learning techniques, including a specially developed CNN model, to improve diagnostic accuracy.

Methods: A dataset of 1097 lung CT images was balanced using GANs and preprocessed with techniques like histogram equalization and noise reduction. The data was split into 70% training and 30% testing sets. Models including VGG19, AlexNet, InceptionV3, ResNet50, and a custom-designed CNN were trained. Additionally, Faster R-CNN-based region proposal methods were integrated to enhance detection performance.

Results: The custom CNN model achieved the highest accuracy at 99%, surpassing other architectures like VGG19, which reached 97%. The Faster R-CNN integration further improved sensitivity and classification precision.

Conclusion: The results demonstrate the effectiveness of GAN-supported deep learning models for lung cancer classification, highlighting their potential clinical applications for early detection and diagnosis.