Journal of Biomimetics, Biomaterials and Biomedical Engineering Vol. 73

Abstract: In the textile and garment industry, cotton fabric is widely used in the production of sportswear and socks due to its comfortability, breathability, and excellent moisture absorption. However, its hydrophilic and porous nature creates favorable microbial growth conditions, especially under frequent exposure to sweat and contaminants. To address this limitation, we developed a simple and scalable dip-coating approach to enhance the antibacterial and mechanical properties of cotton fabric by applying a chitosan/silver nanoparticles hybrid layer (CS/AgNPs). Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) confirmed the uniform surface morphology and chemical integration of coatings. Compared to untreated fabric, the tensile strength increased by 36.7% in the weft direction, and tear strength improved by 27.96% in the warp direction, whereas it remained unchanged in the weft direction. The agar diffusion assays showed the effective antibacterial activity against Bacillus cereus and Escherichia coli after 20 washing cycles, thereby demonstrating the wash durability of treated fabrics. These results reveal that cotton textiles coated with CS/AgNPs enhanced the antibacterial, mechanical, and durability performance, indicating potential application in the textile and clothes industry.

Abstract: Zinc-substituted copper ferrite (Cu_1-xZn_xFe₂O₄) nanocomposites were synthesized in a polyethylene glycol (PEG) matrix via a sol–gel auto-combustion method to enhance biocompatibility and functional performance. Structural, optical, morphological, and magnetic properties were systematically investigated using XRD, FTIR, SEM, EDS, UV–Vis spectroscopy, and VSM. XRD confirmed a single-phase inverse spinel cubic structure, with crystallite sizes decreasing from 14.63 nm (pristine) to 9.14, 8.21, and 9.90 nm for x = 0.2, 0.4, and 0.6, respectively, based on the Williamson–Hall method. A slight reduction in bandgap energy (3.56–3.52 eV) was observed with increasing Zn content. FTIR analysis verified PEG functionalization, indicating improved stability and biocompatibility. SEM images revealed agglomerated nanostructures with rough surfaces, promoting reactive oxygen species generation and metal ion (Cu²⁺/Zn²⁺) release, which are beneficial for antimicrobial activity. Magnetic measurements demonstrated superparamagnetic behavior with near-zero coercivity, supporting biomedical applicability. The nanocomposites exhibited enhanced antibacterial and antifungal activities compared to standard drugs (cefixime and clotrimazole), with stronger effects against fungal strains. Additionally, notable antioxidant activity was observed. These findings highlight the potential of PEG-assisted Zn-substituted copper ferrite nanocomposites as multifunctional materials for antimicrobial and antioxidant biomedical applications.

Abstract: This study investigates the biodegradability of composite materials containing dacarbazine (DAC), synthesized from hydrophilic polyurethane-ureas (PUUs) incorporating fragments of 4,4′-diaminodiphenylmethane (DADPh) and a poly(vinyl alcohol)-poly(ethylene glycol) (PVA-PEG) graft copolymer under simulated inflammatory conditions mimicking blood contact. Biodegradability was assessed using Fourier-transform infrared (FTIR) spectroscopy, tensile testing, differential scanning calorimetry (DSC), and Transmission Optical Microscopy (TOM) by analyzing changes in the structural, mechanical, thermophysical properties, and composite surface morphology after 1, 3, and 6 months of incubation in Fenton’s reagent. The results revealed that DAC-containing composites undergo surface structural rearrangements characterized by alterations in hydrogen bonding and partial cleavage of chemical bonds under oxidative conditions. These findings confirm that PUU-based DAC composites containing DADPh and PVA-PEG fragments are susceptible to oxidative degradation in Fenton’s reagent. The biodegradability of these materials ensures controlled DAC release during progressive polymer matrix degradation, highlighting their potential as temporary implantable systems for localized delivery of the antitumor agent DAC.

Abstract: Nerve tissue regeneration represents a fundamental scientific challenge, especially in large spinal cord injuries inhibited by natural biological factors. The ability of peripheral nerves to spontaneously repair small injuries is limited, necessitating complex surgical grafts with secondary complications in larger cases. This research develops a revolutionary strategy based on hybrid nanobridges made from a scientifically proven combination of graphene (59%) and boron nitride (41%). Graphene provides ultrafast electrical conductivity (1.6 × 10⁶ m/s), while boron nitride ensures optimal biocompatibility (9.4/10) and mechanical stability. The results revealed that the optimal hybrid ratio increased the efficiency of nerve signal transmission by 40%, and increased the quantum tunneling probability to 0.65 at 3 nm, accelerating axonal regeneration. The high electric field concentration (0.1 V/nm) in the nucleus allows for precise stimulation of damaged cells. By combining the superior electrochemical properties of graphene with the optimal biocompatibility of boron nitride, these nanobridges represent a quantum leap in neural tissue engineering, opening new horizons for treating spinal paralysis and complex injuries.

Abstract: Chitosan, a biopolymer derived from chitin found in the exoskeletons of crustaceans and in insects, is known for its non-toxic, biocompatible, and biodegradable properties, making it highly valuable in biomedical applications. However, the high cost and variable purity of commercially available chitosan limit its widespread use. This study focuses on the synthesis and characterization of alpha-origin chitosan from Penaeus indicus exoskeleton waste using a multi-step process, including deproteinization, demineralization, deacetylation, and purification. Two purification strategies were employed; one incorporating a demetallization step to enhance material quality. Characterization was performed using contact angle analysis, Scanning Electron Microscopy (SEM), stereo microscopy, Energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FTIR). The synthesized chitosan exhibited hydrophilic characteristics, with contact angles ranging from 61° to 73°, confirming its biodegradability and biocompatibility. The structural analysis of purified samples revealed improved porosity, surface morphology, and fibrous features. The removal of metallic impurities was confirmed by EDS, with oxygen and carbon making 99% of the composition of material. A high degree of deacetylation (>80%) was demonstrated by FTIR analysis. The most refined chemical profile was found to be exhibited by the demetallized chitosan. These results indicate that local shrimp shells can be used to synthesize high-purity α-chitosan with physicochemical properties similar to commercially used chitosan. The incorporation of demetallization step significantly improved the structural features and chemical purity of the material, making it suitable for biomedical applications. The proposed method provides a scalable, sustainable, and cost-effective synthesis approach that use inexpensive marine waste and reduce dependence on imported raw materials for producing high-quality chitosan for both industrial and biomedical applications.

Abstract: This study examines the physicochemical properties of a hydrogel composed of poly(vinyl alcohol) (PVA) and bacterial cellulose (BC), modified with silver nanoparticles (AgNPs) previously synthesised via green methods using Lactobacillus acidophilus UCM B-2691. The effects of composition on moisture content, sorption behavior, and moisture desorption were assessed, and the density of the obtained samples was investigated. Increasing the bacterial cellulose content in hydrogels enhances their hydrophilicity, water-holding capacity, and sorption properties. The incorporated AgNPs are not released from the hydrogels and do not exhibit antimicrobial activity; instead, they promote the formation of a more porous, structurally stable network, which enhances sorption and lowers density. PVA/BC hydrogels containing 40–60% BC and AgNPs showed the best overall performance, combining high hydrophilicity, structural stability, and porosity. The results indicate the high potential of these hydrogel systems for biomedical technologies, particularly in controlled drug delivery and tissue engineering.

Abstract: Linde Type A (LTA) zeolite, with its unique structural properties, has emerged as a potential candidate for controlled drug delivery in biomedical applications. This locally obtained zeolite can be utilised to deliver drugs for the treatment of cancer. The study investigated the synthesis and characterization of LTA zeolite at different temperatures (60°C, 80°C, and 105°C) and their potential for drug delivery. Fourier-transformed infrared spectroscopy (FTIR) confirmed the presence of LTA zeolite, while helium ion microscopy (HIM) and scanning electron microscopy (SEM) revealed distinct morphological changes upon drug loading. Brunauer-Emmett-Teller (BET) analysis demonstrated variations in surface area, pore size, and pore volume between raw zeolite and drug-loaded zeolite. X-ray diffraction (XRD) analysis revealed temperature-dependent changes in crystallite size and crystallinity, with average values of 40.89 nm (65.99% crystallinity) at 60°C, 28.40 nm (71.39%) at 80°C, and 29.76 nm (76.37%) at 105°C for raw zeolite. Drug loading further reduced crystallite size to 24.89 nm (70.79%), 16.44 nm (83.78%), and 26.91 nm (68.82%) at 60°C, 80°C, and 105°C, respectively. These results highlight the potential of LTA zeolite as carriers for cancer drugs, with synthesis temperature and drug loading influencing their physicochemical properties and drug delivery potential.

Abstract: The medical grade 316L stainless steel has been widely used for biomedical implants, including bone tissue engineering scaffolds due to its excellent mechanical properties and biocompatibility. The space holder method offers a promising approach to producing highly porous 316L stainless steel scaffolds. However, several challenges in the implementation of this method remain unresolved, particularly the difficulties in controlling the geometrical changes of space holder particles during the compaction of stainless steel/carbamide powder mixtures, leading to inability to control pore characteristics of the scaffolds produced. In this study, the compaction behavior of stainless steel/carbamide powder mixtures was investigated to understand the interactions between metal particles and space holder particles in the preparation of porous stainless steel scaffolds. The impacts of key process parameters on the green density, such as the specific net energy applied during the process and the yield pressure derived from loading-unloading compression cycles, were analyzed with the aid of the Heckel model. The study provides useful insights into these relationships, facilitating the optimization of the compaction process to achieve desired scaffold architecture and contributing to consistent fabrication of porous 316L stainless steel scaffolds.

Abstract: This study presents the preparation and printing failure analysis of polycaprolactone-magnesium-hydroxyapatite (PCL-Mg-HA) composite filaments intended for Fused Deposition Modeling (FDM) 3D printing. The research aimed to investigate the challenges encountered during the printing process and identify factors affecting the printability of the fabricated biocomposite filaments. The filament was prepared using a double extrusion method, with PCL as the polymer matrix and combined with 3 wt% magnesium (Mg) and 5 wt% hydroxyapatite (HA). The double extrusion process, conducted at 75°C for initial mixing and 55°C for diameter refinement, successfully produced a continuous filament with an average diameter of 1.82 ± 0.05 mm, which closely matched the FDM standard of 1.75 mm. Despite achieving satisfactory filament geometry, the material exhibited poor printability during FDM trials using a Creality Ender 3 V3 SE printer. Printing attempts at nozzle temperatures between 150°C and 180°C resulted in unstable extrusion, nozzle clogging, and incomplete specimen formation. These failures were primarily attributed to the combined effects of high melt viscosity, the sticky behavior of PCL, and the increased stiffness of the composite caused by the Mg and HA fillers. Observations also indicated that the difference in thermal conductivity between PCL and the fillers resulted in uneven melting and localized solidification within the nozzle. Comparative tests using pure PCL filament confirmed similar difficulties, as extrusion remained inconsistent and the printed parts showed weak interlayer adhesion and visible porosity. These findings suggest that the PCL-Mg-HA composite, in its current formulation, is not yet suitable for stable FDM 3D printing due to its rheological and thermal incompatibilities with standard printing conditions. This study offers valuable insights into the processability limitations of PCL-based biocomposite filaments, serving as a reference for future research in developing bioactive materials for bone tissue engineering applications.

Abstract: In order to accommodate the high range of motion (ROM) required for daily activities of Asian populations, such as squatting and kneeling, patients with hip joint diseases require prostheses with a large ROM. However, traditional ceramic-on-ceramic (CoC) hip prostheses have a prominent contradiction: using larger-diameter femoral heads for high flexion significantly increases the risk of ceramic liner fracture. This study draws bionic inspiration from turtle shell morphology. It applies structural bionic design to develop a large-ROM hip prosthesis. A discrete model is built based on turtle shell structure and ceramic size effects. Finite element simulations and tribological experiments are conducted. The results show that a ROM of 142.9° is achieved, the peak stress is only 34.995 MPa (approximately 50% lower than the accepted 70 MPa safety threshold for alumina ceramics), and compared with traditional monolithic prostheses, stress concentration is reduced by 30% and the crack propagation risk by 40%. Structural reliability is ensured by the finite element-optimized geometry and precision-machined ceramic components (Vickers hardness: 2513.2 MPa, surface roughness: Ra ≤ 0.1 μm). This new prosthesis meets patients’ needs, provides references for other joint designs, and enriches the integration of mechanical and bionic design.