Journal of Biomimetics, Biomaterials and Biomedical Engineering Vol. 70

Abstract: Development of drug eluting biodegradable cardiovascular stent materials offers a promising alternative to conventional bare metallic stents due to their excellent biocompatibility and ability to eliminate long-term complications associated with permanent implants. The study presents a novel drug-eluting bilayer coating comprising inner calcium phosphate (CaP), titanium dioxide (TiO₂) and outer DEX-loaded chitosan for magnesium alloy stents. The coating is engineered to enhance corrosion resistance, promote biocompatibility and provide controlled drug release to mitigate restenosis and inflammation. The synergistic properties of CaP-TiO₂ improve the structural stability of the coating, while the chitosan matrix ensures effective drug delivery. In-vitro corrosion measurements and drug release kinetics demonstrate the coating’s potential for dual-functionality as a biodegradable barrier and a therapeutic agent carrier respectively. The innovative approach highlights a significant step towards the development of biodegradable drug-eluting stents tailored for cardiovascular applications.

Abstract: The durability and strength of acrylic dentures are crucial for patient satisfaction and oral health. However, denture failure rates remain a significant concern. Reinforcing acrylic dentures with nanoparticles such as zirconia improves the mechanical properties of PMMA dentures. This study examines the enhancement of mechanical and physical properties of heat-cured PMMA dentures reinforced with varying amounts (1, 3, 5, 7, and 9 wt.%) of YSZrO₂-NP and porcelain particles. The components were fabricated with standard dimensions in a dental flask, compacted using a hydraulic press, and polymerized for 120 minutes in a thermos-stated water curing bath. The properties analyzed included flexural strength, hardness, wear resistance, microstructure, and biocompatibility. The Flexural strength increased significantly with YSZrO₂-NP reinforcement (315% at 7 wt.%), whereas porcelain particles reinforcement showed a minimal increase (40% at 9 wt.%). Hardness slightly decreased for all YSZrO₂-NP/PMMA compositions (51% at 9 wt.%), while porcelain reinforcement showed a slight increase across all amounts, reaching up to 11% at 9 wt.%. Wear resistance improved with all filler additions in the PMMA. SEM analysis revealed uniformly dispersed particles in the PMMA matrix for 1-5 wt. % porcelain particles and ZrO₂NP composites. In contrast, 7-9 wt. % reinforcement showed non-uniform dispersion. Reinforcing PMMA with YSZrO₂-NP and porcelain particles enhanced its mechanical and physical properties. Therefore, micro- and nanoparticles of ceramics are a viable option for improving the strength and rigidity of PMMA dentures.

Abstract: In this study, silver nanoparticles (S-AgNPs) were synthesised using S. amaranthoides leaf extract through a green synthesis approach, and their synthesis conditions were optimised using Response Surface Methodology (RSM) based on a Box–Behnken Design (BBD). The model was statistically significant (F-value = 12.21, p < 0.0017) and showed strong predictive capability (adjusted R² = 0.8631). Optimal synthesis was achieved with 1 mL of 1 mM AgNO₃, 20 minutes of extract exposure, and a reaction temperature of 70 °C. Characterisation techniques, including UV–Vis, FTIR, XRD, SEM, and TEM, confirmed the formation of spherical, crystalline S-AgNPs capped with phytochemicals from the plant extract. Antibacterial analysis revealed potent activity, with the optimised S-AgNPs showing a maximum zone of inhibition of 25.8 mm against MRSA, outperforming the standard antibiotic ceftriaxone. These results demonstrate the efficacy of RSM in fine-tuning synthesis parameters to produce bioactive S-AgNPs using an eco-friendly and sustainable approach.

Abstract: This study systematically evaluated nine surface treatment conditions on titanium dental implant fixtures, combining Sandblasted Large Grit Acid-etched (SLA) with anodizing methods. A total of 112 samples were characterized using FESEM, EDAX, MTT, wettability, surface energy, and osseointegration analyses. Among the tested protocols, the SLA+Anodizing process with the following parameters proved most effective: sandblasting with 75 µm particles at 4 bar and 30° angle, acid etching at 75°C for 6 minutes, and anodizing at 100 V for 5 minutes. This optimized surface demonstrated superior outcomes, including 97% cell viability, enhanced osseointegration within twelve days, and a chemical composition consistent with Grade 5 titanium alloy (Ti-6Al-4V), typically comprising approximately 90% Ti, 6% Al, 4% V, and trace amounts of O, Fe, and other elements.

Abstract: The in vivo measurement of the cartilage contact area (CCA) during shoulder rotation remains unexplored. This study, therefore, investigates changes in the CCA and cartilage contact pattern (CCP) between the humeral head and glenoid during static rotation with abduction using magnetic resonance imaging (MRI) in subjects with normal shoulders. The study subjects were 14 Japanese men without a previous history of shoulder injury or disorder. MRI data were obtained from the transverse sections of the shoulder using a 3T-MRI scanner in the following four postures: neutral posture, posture at neutral rotation with 120° of abduction (AB posture), posture at 100° of external rotation with 120° of abduction (ER posture), and posture at 30° of internal rotation with 120° of abduction (IR posture). The CCA and CCP (contact centroid) of the glenohumeral joint were determined from the MRI data. The CCA in the AB posture was significantly smaller than that in the neutral posture (p = 0.015). The CCAs in the ER and IR postures were approximately 23.1% and 35.2% larger, respectively, than that in the AB posture. The contact centroid at the AB posture was located significantly more superior to those at the neutral, ER, and IR postures (p < 0.001, p = 0.012, p < 0.001, respectively). Results offer new insights into the CCA and CCP of the glenohumeral joint during in vivo shoulder rotation. This study provides a useful reference dataset obtained from young participants with normal shoulders for understanding cartilage contact mechanics. Improved understanding of the contact pattern can help detect shoulder joint disorders and develop subsequent treatment and surgical strategies.

Abstract: The cost of prosthetics is a complex and multifaceted problem affecting individuals in need of these life-changing devices. Myoelectric prosthetics that can significantly improve the quality of life of individuals with upper limb amputations cost around $4000(6,105,000 naira) to $10,000(15,262,500 naira) for even the most basic models, this is a challenge for individuals in developing and underdeveloped countries as they cannot afford these prostheses. However, low-cost prosthetics are mostly non-functional with the functional prosthetic solutions having limited range of movement. Hence, the main objective of this research was to create a functional and affordable upper limb prosthetic device that can respond to muscle signals, enabling natural hand movement. Myoelectric prosthetic hands are artificial limbs controlled by electrical signals generated by the user's residual muscles. These signals are detected by electrodes placed on the skin and translated into movements by a microprocessor within the prosthesis. The myoelectric prosthetic was fabricated using 3D modeling, and the hand components were printed using poly-lactic acid (PLA) to address this issue. The design incorporated five individual fingers, each with multiple segments, to replicate the structure of the human hand. Servo motors were strategically positioned to actuate the finger movements based on myoelectric signals captured by surface electrodes placed on the user’s forearm. The electrical system consisted of an Arduino nanomicrocontroller, an electromyography (EMG) sensor, and various power management components. Calibration procedures were implemented to establish appropriate thresholds for distinguishing between hand movements, such as palm open and grab. The system allows for wider range of movement due to its 5 DOFs (degree of freedom). The system and it also exhibits an average response speed of 1.845 seconds. This cost-effective prosthetic hand would improve the quality of life for amputees and also increase accessibility and affordability to amputees, generally impacting health globally. This design breaks new grounds in low-cost prosthetics by focusing on the use of locally sourced materials and functional control system for the movement of the hand through the use of a simple 3-D printing technology and easily accessible materials precisely assembled together to replace the complex and expensive ones in the market.

Abstract: More than 2,000 women are diagnosed each year with breast cancer in Honduras, and many of them face a mastectomy as the only way to save their lives. For those who do not have access to breast reconstruction, recovery can become even more challenging, as coming to terms with changes in their physical appearance is a significant struggle, especially when the available alternatives are limited and lack personalization. This project arises as a response to that gap, developing a customized external breast prosthesis through 3D modeling and additive manufacturing, with the aim of improving comfort, functionality and aesthetics over conventional prostheses. 3D scanning techniques, biomechanical analysis, clinical interviews and usability testing with a unilateral post-mastectomy patient were employed, resulting in a prosthesis that morphologically adapted to the patient’s body, mimicked the shape of her healthy breast and did not cause sweating. The satisfaction survey conducted after the use of the personalized prosthesis indicated improvements in physical and emotional well-being. Meanwhile, additional questionnaires revealed a lack of access to postoperative psychological support, pointing to the need for more comprehensive recovery approaches. In conclusion, it was validated that the design achieved its overall objective by offering a solution that not only improves the patient’s physical experience, but also brings therapeutic value to the comprehensive post-mastectomy recovery process.

Abstract: To meet the requirements of the lower limb exoskeleton robot working in coordination with the human body and improve the human-machine interaction performance, a lower limb motion intention recognition method based on the dual-stage joint optimization of the Gated Recurrent Unit (GRU) neural network by the Grey Wolf Optimization (GWO) and the Adaptive Boosting (AdaBoost) algorithm is proposed, and the GWO-AdaBoost-GRU intention recognition model is constructed. The Surface electromyography signals of six lower limb movements are collected and processed respectively by the CEEMDAN-WT joint denoising, activity segment extraction, and feature extraction, and the feature vector dataset is constructed as the model input. To comprehensively verify the performance of the GWO-AdaBoost-GRU model, it is compared with the GRU and GWO-GRU models, and an application verification is carried out by building a lower limb exoskeleton rehabilitation system. The experiments show that the average recognition accuracy of the GWO-AdaBoost-GRU model is 95.5%, which is 8.1% higher than that of the GRU model and 3.2% higher than that of the GWO-GRU model. Moreover, in the practical application of the lower limb rehabilitation institution, the GWO-AdaBoost-GRU intention recognition model has high accuracy, can accurately recognize the movement intentions of the subjects, and complete the designated rehabilitation movements in conjunction with the rehabilitation system, demonstrating excellent application performance.

Abstract: Hallux valgus (HV), characterized by triplanar deviation of the first metatarsophalangeal joint, significantly alters foot biomechanics and provokes adaptations along the kinetic chain. While its static effects are well-documented, its dynamic impact during high-velocity, multiplanar maneuvers remains unclear. This study investigated the dose-dependent relationship between HV severity and lower limb stability during side-cutting using a novel multimodal validation framework. Sixty-six male participants (n = 22 per group: normal, mild, and moderate HV) underwent biomechanical evaluation through three-dimensional motion capture, inverse dynamics-driven finite element (FE) modeling, and dynamic fluoroscopy. Real-time bone displacement was quantified using shape-matching algorithms to validate FE simulations. Results indicated compensatory adaptations in HV groups, such as reduced first metatarsal dorsiflexion and external rotation of the first metatarsophalangeal joint. Dynamic fluoroscopic data revealed progressive displacement in the tibiotalar and subtalar joints, with significantly increased posterior glide (p < 0.001). Kinematic correlations showed a decline in ankle plantarflexion (p < 0.001) and hip flexion (p < 0.001) with advancing HV severity, while moderate HV was associated with significantly greater knee valgus angles (R² = 0.47, p < 0.001). FE simulations demonstrated a non-linear increase in contact pressures at the first MTPJ and lateral metatarsal overload. These findings reveal that HV induces a compensatory kinematic cascade through load redistribution and altered joint dynamics, destabilizing three-dimensional lower limb alignment. By linking pathological tissue loads to vector field shifts, this multiscale framework enhances our understanding of injury mechanisms and offers insights into kinematic chain optimization for injury prevention.

Abstract: The absence of customized prostheses for animals significantly limits the rehabilitation of amputated canines in Honduras. Due to the lack of local prosthetic solutions, full limb amputations are commonly performed, which eliminate the possibility of preserving functional joints. As a result, no clinical cases with partial limb preservation are available for study, this paper presents the design and validation of a modular canine exoprosthesis in a simulated transradial amputation scenario. Anatomical data were obtained through zoometry, plaster molding, and 3D scanning. The modular prosthesis was modeled in SolidWorks and Meshmixer, fabricated with FDM 3D printing. Materials used include carbon fiber-reinforced PETG for structural components and TPU with varying hardness for flexible sections. Structural validation was performed through finite element analysis (FEA), followed by experimental compression tests. Results show that the design and materials withstand peak gait forces within safe limits. The modular configuration proved effective for assembly and potential future adjustments. This study provides a technical foundation for the development of anatomically adapted canine prostheses in Honduras, offering an alternative that contributes to improving the quality of life of amputee dogs and supporting their rehabilitation within the local context.