Bio-medical materials and engineering最新文献

BackgroundThe success of dental restorations depends on achieving adequate surface integrity. However, grinding and polishing are generally ineffective because of the special physical and chemical compositions and properties of the composites. Polyurea resin is an elastomer with high elasticity, abrasion resistance, heat resistance, and toughness. When it is used as a bond, grinding wheels with high grain grip strength can be fabricated.ObjectiveWe fabricated a mounted wheel with a polyurea resin as the bond and used it to polish a composite resin and porcelain under clinical polishing conditions. The effects of the approach on the polished surface roughness and morphology were evaluated with respect to the type of mounted wheel, initial surface roughness, abrasive particle size, and polishing time.MethodsThis study fabricates a mounted wheel with polyurea resin as the bond and uses it to polish composite resin and porcelain under clinical polishing conditions. The effects of the approach on the polished surface roughness and morphology are evaluated against the type of mounted wheel, initial surface roughness, abrasive particle size, and polishing time.ResultsAmong single-crystal diamond, siliconcon carbide (GC), and alumina (WA) abrasive grains, diamond abrasive grains produced the best finish for most tested resin composites. However, WA abrasive grains are effective for polishing Estenia (it has the highest filler content). The polishing performance of the porcelain varied with the initial surface roughness and abrasive particle diameter.ConclusionThis study provides guidance for improving and developing mounted wheels for clinical applications.

BackgroundThe differences in bony alignment of the lower extremities during gait compared to standing remain unclear.ObjectiveThis 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.MethodsThirty-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.ResultsCompared 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.ConclusionLower 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.

BackgroundIschemic stroke is a medical condition caused by occlusion of blood vessels in brain, resulting in disruption of blood flow to the brain and triggering irreversible damage to the neuronal cells. While stem cells transplantation has been proposed as a potential alternative therapym for ischemic stroke, its effectiveness is limited due to low cell survival rate and potential side effects following transplantation. To overcome these challenges and enhance therapeutics efficacy, researchers have focused on developing various biomaterials to create a sustainable cellular microenvironment or to modify the properties of donor stem cell which could optimize their reparative functions in injured brain tissues.ObjectiveThis review aims to explore and discuss the different types of biomaterials that have been applied in the treatment of ischemic stroke, shedding light on their potentials as promising therapeutics options for this debilitating condition.MethodsLiterature search was performed to identify publications studying the potential of three biomaterials namely: nanobioparticles, hydrogels and extracellular vesicles for ischemic stroke therapy in vitro, in vivo or in clinical using four databases, namely: PubMed, ScienceDirect, Web of Science and Scopus.Results and discussionThe major benefits obtained from the application of nanobioparticles for ischemic stroke therapy included as the nanocarrier for drug/cell delivery, cell tracking, real time imaging, promote cell proliferation, while hydrogels provided scaffold support and conferred neuroprotection to stem cells, as well as provided neurotropic effects and controlled drug release for localized treatment. Lastly the extracellular vesicles were identified as a cell-free treatment strategy in promoting angiogenesis, neuronal differentiation and neurogenesis for ischemic stroke treatment.ConclusionBiomaterial-based therapies have their own potentials and further clinical investigations are strongly recommended to translate the therapies into more conscientious evidence-based therapy for clinical application.

BackgroundTuberculosis (TB) is a global health challenge from a single infectious agent, Mycobacterium tuberculosis (MTB), and it demands improved diagnostics and therapies.ObjectiveThis work explored a novel method for detecting MTB by combining nanogold labeling (NGL) technology with silver staining to enhance sensitivity and specificity.MethodsNanogold particles (NGPs) were characterized using ultraviolet absorption spectroscopy (UVAS), and their morphology was observed via transmission electron microscopy (TEM). The silver staining enhancement (SSE) system was optimized for a reaction time of 11 min. Fifty drug-resistant tuberculosis (DRT) patients were randomly assigned to a control (Ctrl) group receiving conventional nursing and an experimental (Exp) group treated with continuous nursing intervention (CNI). Quality of Life Instrument for Tuberculosis Patients (QLI-TB) scores were compared over 6 months.ResultsUnmarked NGPs were evenly distributed, while labeled NGPs maintained complete morphology with a gray halo. The detection limit was established at 0.582, reaching as low as 1 pmol/L. For sputum specimens, detection rates were 38.7% for culture, 41.94% for PCR, and 43.54% for nanogold SSE, with no significant differences (P > 0.05). However, patients in the Exp group exhibited significant improvements in physical, psychological, and social functions, as well as the tuberculosis-specific module (TSM) compared to the Ctrl group (P < 0.05).ConclusionsWe demonstrated an innovative method for detecting MTB, demonstrating promising results through method optimization and analysis.

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.

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.

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.