Frontiers in Bioengineering and Biotechnology最新文献

Introduction: Anterior knee pain and other patello-femoral (PF) complications frequently limit the success of total knee arthroplasty as the final treatment of end stage osteoarthritis. However, knowledge about the in-vivo loading conditions at the PF joint remains limited, as no direct measurements are available. We hypothesised that the external knee flexion moment (EFM) is highly predictive of the PF contact forces during activities with substantial flexion of the loaded knee.

Materials and methods: Six patients (65-80 years, 67-101 kg) with total knee arthroplasty (TKA) performed two activities of daily living: sit-stand-sit and squat. Tibio-femoral (TF) contact forces were measured in vivo using instrumented tibial components, while synchronously internal TF and PF kinematics were captured with mobile fluoroscopy. The measurements were used to compute PF contact forces using patient specific musculoskeletal models. The relationship between the EFM and the PF contact force was quantified using linear regression.

Results: Mean peak TF contact forces of 1.97-3.24 times body weight (BW) were found while peak PF forces reached 1.75 to 3.29 times body weight (BW). The peak EFM ranged from 3.2 to 5.9 %BW times body height, and was a good predictor of the PF contact force (R ² = 0.95 and 0.88 for sit-stand-sit and squat, respectively).

Discussion: The novel combination of in vivo TF contact forces and internal patellar kinematics enabled a reliable assessment of PF contact forces. The results of the regression analysis suggest that PF forces can be estimated based solely on the EFM from quantitative gait analysis. Our study also demonstrates the relevance of PF contact forces, which reach magnitudes similar to TF forces during activities of daily living.

The purpose of this study is to evaluate the optimum frequency of oscillatory fluid flow (OFF) for increasing osteogenesis in human dental pulp cells (DPCs) in an incubating rocking shaker. DPCs from 3 donors were cultured in an osteogenic induction medium (OIM) and mechanical stimulation was applied using an incubating rocking shaker at frequencies of 0 (control), 10, 20, 30, and 40 round per minute (RPM) for 1 h/day, 5 days/week. Cell proliferation was measured using total protein quantification, and osteogenic activity was measured by alkaline phosphatase (ALP) activity, calcium deposition, and collagen production on days 7, 14, and 21 of culture. Results of DPCs morphology in the 30 RPM group were more clustered and formed interconnections between cells. Results of DPC proliferation and collagen production showed no significant differences between the experiment groups. The ALP activity on day 7 and 14, and calcium deposition on day 21 of the 30 RPM group were significantly higher than the control groups. Thus 30 RPM is likely an effective frequency for increasing calcium deposition. This study uses strategies in Tissue Engineering followed the research topic about an application of human cells to stimulate oral and maxillofacial hard tissue regeneration. In the future, the mineralization of DPCs could be enhanced by using an incubating rocking shaker at 30 RPM in the lab to create a cell sheet. The mineralized cell sheet could then be implanted into the patient for bone repair of orofacial defects.

Introduction: Accurate prediction of knee biomechanics during total knee replacement (TKR) surgery is crucial for optimal outcomes. This study investigates the application of machine learning (ML) techniques for real-time prediction of knee joint mechanics.

Methods: A validated finite element (FE) model of the lower limb was used to generate a dataset of knee joint kinematics, kinetics, and contact mechanics. The models were trained on joint alignment data, ligament information, and external boundary conditions. Several predictive algorithms were explored, including linear regression (LRM), multilayer perceptron (MLP), bi-directional long short-term memory (biLSTM), convolutional neural network (CNN), and transformer-based approaches. The performance of these models was evaluated using average normalized root mean squared error (nRMSE).

Results: The biLSTM model achieved the highest accuracy, with a significantly lower nRMSE compared to other models. Compared to traditional FE or rigid body dynamics models, these predictive models offered significantly faster prediction speeds, enabling near-instantaneous insights into the TKR system's performance. The small size of the predictive models makes them suitable for deployment on edge devices potentially used in operating rooms.

Discussion: These findings suggest that real-time biomechanical prediction using biLSTM models has the potential to provide valuable feedback for surgeons during TKR surgery. Applications of this work could be applied to provide pre-operative guidance on optimal target implant alignment or given the real-time prediction ability of these models, could also be used intra-operatively after integration of patient-specific intra-op kinematic and soft-tissue information.

Accelerating the genetic selection to obtain animals more resilient to climate changes, and with a lower environmental impact, would greatly benefit by a substantial shortening of the generation interval. One way to achieve this goal is to generate male gametes directly from embryos. However, spermatogenesis is a complex biological process that, at present, can be partially reproduced in vitro only in the mouse. The development of reliable 3D in vitro models able to mimic the architecture and the physiological microenvironment of the testis, represents a possible strategy to facilitate ex vivo haploid male gamete generation in domestic species. Here we describe the creation of bovine testicular bio-scaffolds and their successful repopulation in vitro with bovine testicular cells. In particular, bovine testes are subjected to three different decellularization protocols. Cellular compartment removal and extracellular matrix preservation are evaluated. The generated bio-scaffolds are then repopulated with bovine testicular fibroblasts. The results obtained demonstrate that the decellularization protocol involving the use of 0.3% sodium dodecyl sulfate (SDS) for 12 h efficiently eliminates native cells, while preserving intact ECM composition and microstructure. Its subsequent repopulation with bovine fibroblasts demonstrates successful cell homing, colonization and growth, consistent with the scaffold ability to sustain cell adherence and proliferation. Overall, the generated 3D bio-scaffolds may constitute a suitable artificial niche for ex vivo culture of testicular cells and may represent a possible strategy to reproduce spermatogenesis in vitro.

Objective: This study investigated upper limb kinematics and muscle co-activation in wheelchair tennis players during the forehand stroke. By analyzing linear and angular kinematic variables alongside muscle co-activation patterns, the study aimed to provide insights into the biomechanical mechanisms supporting forehand stroke performance.

Method: Fifteen professional male wheelchair tennis players (height: 163.9 ± 2.05 cm; mass: 64.1 ± 3.07 kg; age: 32.2 ± 7.97 years) participated in this study. Electromyographic data from six muscles around the dominant arm joints were recorded using the Myon system. Four fixed GoPro Hero 8 cameras (120 Hz) captured 3D video, and kinematic analyses were performed using the APAS system. The forehand stroke was analyzed across three phases: (1) backswing, (2) forwardswing, and (3) follow-through.

Results: The results showed significant phase-specific changes in muscle co-activation for the shoulder (p < 0.001), elbow (p < 0.005), and wrist (p < 0.01). Muscle co-activation was highest during the backswing phase, decreased during the forwardswing, and increased again during the follow-through phase. This pattern reflects the need for joint stability and control, particularly when changing stroke direction and slowing the arm after impact.

Conclusion: These findings provide novel insights into the kinematic and neuromuscular mechanisms underlying the forehand stroke in wheelchair tennis. The data provide hypotheses about potential training and rehabilitation strategies that should be tested by prospective studies. The results also highlight the unique demands of wheelchair tennis, contributing to inclusive, evidence-based approaches to enhancing performance and safety in disability sports.

Introduction: Research on head impact characteristics, especially position-specific investigations in football, has predominantly focused on collegiate and professional levels, leaving a gap in understanding the risks faced by high school players. Therefore, this study aimed to investigate the effect of three factors-player position, impact location, and impact type-on the frequency, severity, and characteristics of impacts in high school American football. Additionally, we examined whether and how player position influences the distribution of impact locations and types.

Methods: Sixteen high school football players aged 14 to 17 participated in this study. Validated mouthguard sensors measured head impact kinematics, including linear acceleration, angular acceleration, and angular velocity across ten games, and were used to identify impact locations on the head. Video recordings verified true impacts, player position, and impact type at the moment of each recorded impact. Head impact kinematics were input into a head finite element model to determine the 95th percentile of the maximum principal strain and strain rate. Several novel and systematic approaches, such as normalization, binning, and clustering, were introduced and utilized to investigate the frequency and severity of head impacts across the three aforementioned factors while addressing some of the limitations of previous methodologies in the field. To that end, the number of recorded impacts for each player position during each game was divided by the number of players in that position, and then averaged across ten games. Instead of averaging, impacts were categorized into four severity bins: low, mid-low, mid-high and high. Clusters for the three factors were also identified according to the characteristics of impacts.

Results and discussion: Results revealed that offensive linemen and running backs experienced a higher normalized frequency and more severe impacts across all head kinematics and brain tissue deformation parameters. Frontal impacts, resulting from "head-to-head" impacts, were the most frequent and severe impact locations. The distributions of impact location and type for each specific position were distinct. Offensive linemen had the highest proportion of frontal impacts, while quarterbacks and centerbacks had more impacts at the rear location. These findings can inform interventions in game regulations, training practices, and helmet design to mitigate injury risks in high school football.

A one-step hydrothermal method was applied to prepare carbon dots (CDs) with superior fluorescence properties using chitosan as a carbon source. The as-prepared carbon dots were then grafted onto a sodium alginate-gelatin hydrogel film to form a fluorescent hydrogel film (FHGF), emitting at 450 nm under excitation of 350 nm light. In comparison to the CDs, the fluorescence intensity of this film was maintained over 90.0% and the luminescence position remained basically unchanged, caused by the unchanged surface light-emitting structure of the CDs, due to the existence of electrostatic repulsion between the CDs and the hydrogel. Moreover, the tensile-stress of the fluorescent film with 1.0 wt.% of the CDs was increased by 200% to 10.3 Mpa, and the strain was increased from 117% to 153%. The above experimental results are attributed to the hydrogen bonding between the CDs and the sodium alginate-gelatin hydrogel from analyses of the FT-IR spectra. Interestingly, Fe³⁺ exerted a great quenching effect on this fluorescent film in the concentration range of 0-1.8 μM. The film can be basically used recyclically to detect Fe³⁺ in solution with a detection limit as low as 0.043 μM. In a word, this work demonstrated an enormous potential of carbon dots in fabricating mechanical and fluorescent properties of the hydrogel and proposed a new detection platform for Fe³⁺. In view of the promising Fe³⁺ detection capacity, this hydrogel film can also be applied in oral bacteria surveillance and semi-quantification of ferroptosis in oral cancer.

Objectives: To explore the acute intervention effects of tissue flossing on chronic knee pain (CKP) in boxers.

Methods: Eighteen boxers with CKP (12 male/6 female) were randomly divided into an experimental group (EG) with tissue flossing (n = 9) and a control group (CG) (n = 9). The visual analog scale (VAS), Lysholm knee function score, flexion range of motion (ROM), maximal isometric extensor muscle strength, and stability of the knee were measured pre- and post-intervention (EG: 3-minute tissue flossing, CG: rest).

Results: VAS (F = 15.849, p = 0.001, η ² _p = 0.498) and Lysholm knee function (F = 9.327, p = 0.008, η ² _p = 0.357) significantly improved more in the EG than in the CG. There was a significant difference for maximal isometric extensor muscle strength (F = 17.769, p = 0.001, η ² _p = 0.542) and knee stability (F = 13.844, p = 0.002, η ² _p = 0.464) but no significant difference for ROM (F = 1.218, p = 0.287, η ² _p = 0.075) between the EG and CG.

Conclusion: Tissue flossing can reduce knee pain, improve knee function, increase knee extensor strength, and improve knee stability in boxers with CKP.

Single-cell protein analysis has emerged as a powerful tool for understanding cellular heterogeneity and deciphering the complex mechanisms governing cellular function and fate. This review provides a comprehensive examination of the latest methodologies, including sophisticated cell isolation techniques (Fluorescence-Activated Cell Sorting (FACS), Magnetic-Activated Cell Sorting (MACS), Laser Capture Microdissection (LCM), manual cell picking, and microfluidics) and advanced approaches for protein profiling and protein-protein interaction analysis. The unique strengths, limitations, and opportunities of each method are discussed, along with their contributions to unraveling gene regulatory networks, cellular states, and disease mechanisms. The importance of data analysis and computational methods in extracting meaningful biological insights from the complex data generated by these technologies is also highlighted. By discussing recent progress, technological innovations, and potential future directions, this review emphasizes the critical role of single-cell protein analysis in advancing life science research and its promising applications in precision medicine, biomarker discovery, and targeted therapeutics. Deciphering cellular complexity at the single-cell level holds immense potential for transforming our understanding of biological processes and ultimately improving human health.