Bio-medical materials and engineering最新文献

Background: Cerium ions promote osteoclastogenesis and activate bone metabolism, while cerium oxide nanoparticles exhibit potent anti-inflammatory properties, making them promising for biomedical applications.

Objective: The purpose of this study was to develop and evaluate a synthesis method for sustained-release cerium-ion bioceramics containing apatite. Substituted apatite was found to be an effective biomaterial.

Methods: Cerium-containing chlorapatite was synthesized using a mechanochemical method employing dicalcium phosphate, cerium chloride heptahydrate, and calcium hydroxide as raw materials. The synthesized samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Raman spectroscopy.

Results: Cerium chlorapatite was successfully synthesized in the 10.1% and 20.1% samples. However, at Ce concentrations higher than 30.2%, the samples consisted of three or more phases, indicating the instability of a single phase.

Conclusion: The method used in this study was found to be more efficient and cost-effective than the precipitation method for producing substituted apatite and calcium phosphate-based biomaterials. This research contributes to the development of sustained-release cerium-ion bioceramics with potential applications in the field of biomedicine.

Background: It is imperative to design a suitable material for bone regeneration that emulates the microstructure and compositional framework of natural bone while mitigating the shortcomings of current repair materials.

Objective: The aim of the study is to synthesize a 3D aerogel scaffold composed of PLCL/gelatin electro-spun nanofiber loaded with Simvastatin and investigate its biocompatibility as well as its performance in cell proliferation and ossification differentiation.

Methods: PLCL/gelatin nanofibers were fabricated in coaxial electrospinning with simvastatin added. Fibers were fragmented, pipetted into molds, frozen, and dried. The morphology of fibers and contact angles in 4 groups of PLCL, PLCL@S, 3D-PLCL, and 3D-PLCL@S was observed and compared. MC3T3-E1 cells were planted at the four materials to observe cell growth status, and ALP and ARS tests were conducted to compare the ossification of cells.

Results: TEM scanning showed the coaxial fiber of the inner PLCL and outer gelatin. The mean diameter of the PLCL/gelatin fibers is 561 ± 95 nm and 631 ± 103 nm after the drug loading. SEM showed the fibers in the 3D-PLCL@S group were more curled and loose with more space interlaced. The contact angle in this group was 27.1°, the smallest one. Drug release test demonstrated that simvastatin concentration in the 3D-PLCL@S could remain at a relatively high level compared to the control group. The cell proliferation test showed that MC3T3-EI cells could embed into the scaffold deeply and exhibit higher viability in the 3D-PLCL@S group than other groups. The ossification tests of ALP and ARS also inferred that the 3D-PLCL@S scaffold could offer a better osteogenic differentiation matrix.

Conclusion: The PLCL/gelatin aerogel scaffold, when loaded with Simvastatin, demonstrates a more pronounced potential in enhancing osteoblast proliferation and osteogenic differentiation. We hypothesize that this scaffold could serve as a promising material for addressing bone defects.

Background: Osteoarthritis (OA) is a chronic and degenerative joint disease that remains a great challenge in treatment due to the lack of effective therapies. 4-octyl itaconate (4-OI) is a novel and potent modulator of inflammation for the treatment of inflammatory disease. However, the clinical usage of 4-OI is limited due to its poor solubility and low bioavailability. As a promising drug delivery strategy, injectable hydrogels offers an effective approach to address these limitations of 4-OI.

Objective: The aim of the study was to verify that the composite 4-OI/SA hydrogels could achieve a controlled release of 4-OI and reduce damage to articular cartilage in the group of osteoarthritic rats treated with the system.

Methods: In this study, an injectable composite hydrogel containing sodium alginate (SA) and 4-octyl itaconate (4-OI) has been developed for continuous intra-articular administration in the treatment of OA.

Results: After intra-articular injection in arthritic rats, the as-prepared 4-OI/SA hydrogel containing of 62.5 μM 4-OI effectively significantly reduced the expression of TNF-α, IL-1β, IL-6 and MMP3 in the ankle fluid. Most importantly, the as-prepared 4-OI/SA hydrogel system restored the morphological parameters of the ankle joints close to normal.

Conclusion: 4-OI/SA hydrogel shows a good anti-inflammatory activity and reverse cartilage disruption, which provide a new strategy for the clinical treatment of OA.

Background: Electrospun nanofibers could simulate the natural extracellular matrix (ECM) of the host bone, while minocycline (MINO) is a broad-spectrum tetracycline antibiotic which has been found to have multiple non-antibiotics biological effects that promotes osteogenesis in vitro and in vivo.

Objective: The present study aims at constructing a polylactic acid (PLA) electrospun nanofiber membrane loaded with MINO to enhance Bone marrow mesenchymal stem cells (BMSCs) adhesion and proliferation for early clinical treatment.

Methods: The MINO-PLA membrane were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and in vitro drug release study. The antibacterial ability was also investigated. In addition, in vitro cellular proliferation experiment was performed to verify whether the PLA electrospun nanofibers membrane loaded with MINO enhance BMSCs adhesion and proliferation.

Results: Analyzing the drug release and cell growth results, it was found that only the effective concentration of MINO-PLA could help the growth of BMSCs in the short term. This is related to the drug release rate of MINO-PLA and the initial concentration of MINO.

Conclusion: This study shows that by controlling the concentration and release rate of MINO with electrospinning PLA, BMSCs could proliferate on it, and a new bone repair material had been made in this study.

Background: Tissue engineering seeks to improve, maintain, or replace the biological functions of damaged organs or tissues with biological substitutes such as the development of scaffolds. In the case of bone tissue, they must have excellent mechanical properties like native bone.

Objective: In this work, three geometric models were designed for scaffolds with different structure lattices and porosity that could be biomechanically suitable and support cell growth for trabecular bone replacement applications in tissue engineering and regenerative medicine to the proximal femur area.

Methods: Geometries were designed using computer-aided design (CAD) software and evaluated using finite element analysis in compression tests. Three loads were considered according to the daily activity: 1177 N for slow walking, 2060 N for fast walking, and 245.25 N for a person in a bipedal position. All these loads for an adult weight of 75 kg. For each of them, three biomaterials were assigned: two polymers (poly-glycolic acid (PGA) and poly-lactic acid (PLA)) and one mineral (hydroxyapatite (HA)). 54 tests were performed: 27 for each of the tests.

Results: The results showed Young's modulus (E) between 1 and 4 GPa.

Conclusion: If the resultant E is in the range of 0.1 to 5 GPa, the biomaterial is considered an appropriate alternative for the trabecular bone which is the main component of the proximal bone. However, for the models applied in this study, the best option is the poly-lactic acid which will allow absorbing the acting loads.

Background: The emergence of the global problem of multi-drug resistant bacteria (MDR) is closely related to the improper use of antibiotics, which gives birth to an urgent need for antimicrobial innovation in the medical and health field. Silver nanoparticles (AgNPs) show significant antibacterial potential because of their unique physical and chemical properties. By accurately regulating the morphology, size and surface properties of AgNPs, the antibacterial properties of AgNPs can be effectively enhanced and become a next generation antibacterial material with great development potential.

Objective: The detection of the inhibitory effect of AgNPs on MDR provides more possibilities for the research and development of new antimicrobial agents.

Methods: Promote the formation of AgNPs by redox reaction; determine the minimum inhibitory concentration (MIC) of AgNPs to bacteria by broth microdilution method; evaluate the killing efficacy of AgNPs against multi-drug-resistant bacteria by plate counting; evaluate the inhibitory effect of AgNPs on biofilm construction by crystal violet staining; study the drug resistance of bacteria by gradually increasing the concentration of AgNPs; and detect the toxicity of AgNPs to cells by CCK-8 method.

Results: AgNPs has a significant bactericidal effect on a variety of drug-resistant bacteria. After exposure to AgNPs solution for 12 hours, the number of E. coli decreased sharply, and S. aureus was basically eliminated after 16 hours. In particular, AgNPs showed stronger inhibition against Gram-negative bacteria. In addition, AgNPs can effectively hinder the formation of bacterial biofilm, and its inhibitory effect increases with the increase of AgNPs solution concentration. When AgNPs is used for a long time, the development of bacterial resistance to it is slow. From the point of view of safety, AgNPs has no harmful effects on organisms and has biosafety.

Conclusion: AgNPs can inhibit MDR, and the bacteriostatic ability of Gram-negative bacteria is higher than that of Gram-positive bacteria. It can also inhibit the formation of bacterial biofilm, avoid drug resistance and reduce cytotoxicity.

Background: The prosthetic foot is an essential component of the prosthetic limb used by people who suffer from amputation. The prosthetic foot or limb is expensive in developing countries and cannot be used by most people with special needs.

Objective: In this study, an uncomplicated prosthetic foot is designed that can be manufactured at low costs using 3D printer technology and can be provided to a wide range of amputees. The foot was designed using CAD software and analyzed using ANSES.

Methods: Carbon fiber material was chosen to be suitable for the manufacturing process using 3D printer technology. The selected material was tested in tensile and fatigue tests to determine its mechanical properties. The numerical analysis was carried out assuming the use of an artificial foot by a patient weighing 85 kg.

Results: The results showed that the material proposed for manufacturing has good mechanical properties for this application. The results of the engineering analysis also showed that the model has successfully passed the design process and is reliable for use by amputees.

Conclusion: The success model designed in this study in the numerical analysis process gives reliability to the use of this design to manufacture the prosthetic foot.

Background: The ligament is the soft tissue that connects bone to bone and, in case of severe injury or rupture, it cannot heal itself mainly because of its poor vascularity and dynamic nature. Tissue engineering carries the potential to restore the injured tissue functions by utilization of scaffolds mimicking the structure of native ligament. Collagen fibrils in the anterior cruciate ligament (ACL) have a diameter ranging from 20 to 300 nm, which defines the physical and mechanical properties of the tissue. Also, the ACL tissue exhibited a bimodal distribution of collagen fibrils. Currently, the ability to fabricate scaffolds replicating this structure is a significant challenge.

Objective: This work aims at i) measuring the diameter of collagens of bovine ACL tissue, ii) investigating the fabrication of sub-100 nm fibers, and iii) fabricating aligned scaffolds with bimodal diameter distribution (with two peaks) resembling the healthy ACL structure. It is hypothesized that such scaffolds can be produced by electrospinning polycaprolactone (PCL) solutions.

Methods: To test the hypothesis, various PCL solutions were formulated in acetone and formic acid in combination with pyridine, and electrospun to generate sub-100 nm fibers. Next, this formulation was adjusted to produce nanofibers with a diameter between 100 nm and 200 nm. Finally, these solutions were combined in the co-electrospinning process, i.e., two-spinneret electrospinning, to fabricate biomimetic scaffolds with a bimodal distribution.

Results: Electrospinning of 8% and 15% PCL solutions, respectively, resulted in the production of fibers with diameters below and above 100 nm. The combined scaffold exhibited a bimodal distribution of aligned fibers with peaks around 80 and 180 nm, thus mimicking the collagen fibrils of healthy ACL tissue.

Conclusion: This research is expected to have a society-wide impact because it aims to enhance the health condition and life quality of a wide range of patients.

Background: This investigation was conducted to encapsulate 316L SS with a Ti-based alloy coating.

Objective: The aim was to fabricate a coating using TiN, TiO2, and TiCoCr powders on 316L SS through the physical vapor deposition (PVD) sputtering process.

Methods: The powders were consecutively coated on 316L SS through the PVD sputtering process with coating durations of 30, 60, and 90 min. Further microhardness, surface roughness, microabrasion, and adhesion strength tests were also carried out.

Results: A 60% improvement in abrasion resistance was observed in TiCoCr-coated samples compared to the uncoated substrate. The X-ray diffraction results confirmed the optimal formation of Ti alloy coatings with corresponding orientation over the SS substrates. Moreover, TiCoCr with a 90 min coating duration had much better surface characteristics than TiO2 and TiN.

Conclusion: The 90 min coating duration should be optimal for coating in steel for bio-implants.

Backgorund: The development of vibration-induced finger disorders is likely associated with combined static and dynamic responses of the fingers to vibration exposure. To study the mechanism of the disorders, a new rat-tail model has been established to mimic the finger vibration and pressure exposures. However, the mechanical behavior of the tail during compression needs to be better understood to improve the model and its applications.

Objective: To investigate the static and time-dependent force responses of the rat tail during compression.

Methods: Compression tests were conducted on Sprague-Dawley cadaver rat tails using a micromechanical system at three deformation velocities and three deformation magnitudes. Contact-width and the time-histories of force and deformation were measured. Additionally, force-relaxation tests were conducted and a Prony series was used to model the force-relaxation behavior of the tail.

Results: The rat tails' force-deformation and stiffness-deformation relationships were strongly nonlinear and time-dependent. Force/stiffness increased with an increase in deformation and deformation velocity. The time-dependent force-relaxation characteristics of the tails can be well described using a Prony series.

Conculsions: We successfully quantified the static and time-dependent force responses of rat tails under compression. The identified mechanical behavior of the tail can help improve the rat-tail model and its applications.