Papers by Keyword: Biomaterial

Abstract: Titanium and its alloys are commonly used for biomedical implants and therefore should have good biocompatibility, suitable levels of strength, fracture toughness, fatigue resistance, and low elastic modulus. Alloying Ti with β-stabilizing elements (Ta, Mo, Nb and V) allows obtaining alloys with elastic modulus closer to that of bone (10-30 GPa), thus minimizing the tendency for stress shielding and bone resorption. A combinatorial method, based on variable composition laser-assisted deposition, has been used for synthesizing Ti-Ta alloys. The alloys were characterized in composition and microstructure by XRD, SEM, and EDS, and mechanical properties were assessed using depth-sensing ultramicroindentation tests. As the Ta content increases from 3 wt% to 36 wt%, the elastic modulus of the alloys decreases from 120 GPa to about 45 Gpa, corresponding to a region formed of the predominant α” (orthorhombic) phase. The lowest value of elastic modulus (45 GPa) was obtained for the Ti-36Ta (wt%) alloy, which is considerably lower than those of commercial Ti alloys currently used (above 110 GPa). Based on these results, volumetric samples of Ti-40Ta alloy were produced by laser deposition, presenting the predominance of the α” (orthorhombic) phase, elastic modulus as (80±12) GPa, and nanohardness as (4.2±0.6) GPa with H_it/E_it equal to 0.052±0.015, which reinforces the viability of using this composition with potential application as a biomaterial.

Abstract: The Ti-13Nb-1.5Mo-3Ta alloy is a recently developed biocompatible metastable β-Ti alloy designed for biomedical application. In this present work, the influence of cold rolling and subsequent annealing heat treatment on grain refinement of Ti-13Nb-1.5Mo-3Ta alloy was investigated. The alloy was cold rolled (CR) to 60% and 90% thickness reductions at room temperature followed by recrystallization annealing at different temperature (800°C-900°C) and time (1.5mins-10mins) before ice-water quenching. X-ray diffraction (XRD) and optical microscopy (OM) were used to characterize the alloy, and microhardness tests were carried out using the Vickers microhardness tester. The results revealed that the annealed alloys exhibited a fully β-phase, while those subjected to cold rolling displayed introduction of stress induced martensite (SIM) α′′-phase along with β-phase. The microhardness of the 60% and 90%CR samples increased significantly to 253 and 283 Vickers hardness (HV), respectively, from an initial value of 198 HV. Annealed samples exhibited a recrystallized microstructure containing fine equiaxed grains with average size of 10-50μm for 60%CR and 8-34μm for 90%CR. The grain refinement mechanisms are probably attributed to the reversal of the SIM α′′-phase back to the more stable β-phase and the recrystallization of the deformed β-phase.

Abstract: Titanium and its alloys could have good biocompatibility, suitable levels of strength, fracture toughness, fatigue resistance and low elastic modulus, which are requirements for metallic materials used as biomaterials. Implants of commercially available Ti alloys show excessive levels of stiffness that cause stress shielding and often lead to bone resorption and failure. For better biomechanical performance, it is necessary to redesign biomaterials with lower elastic modulus. Alloying Ti with β-stabilizing elements (Ta, Mo, Nb) allows obtaining alloys with Young´s modulus closer to that of bone (10-30 GPa), minimizing the tendency for stress shielding and bone resorption. A combinatorial method, based on variable composition laser deposition, has been used for synthesizing alloys with a gradient of composition along a single clad track and scanning for the most interesting compositions. This study reports results on laser synthesis of alloys in the Ti-5Mo-xNb system, in search for compositions with microstructure and properties optimized for use as biomaterials. The alloys were then characterized in composition and microstructure by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The mechanical properties were assessed using depth-sensing ultramicroindentation tests. Their microstructures consist of the orthorhombic α’ phase with martensitic morphology, and untransformed β. The alloys indentation hardness increased with the Nb content from 2.79 ± 0.02 GPa to 3.7 ± 0.8 GPa, due to solid solution strengthening. The same trend was observed in the elastic moduli that increased from 38.8 ± 8.1 GPa to 76 ± 13 GPa, and in addition the H/E ratio was greater than 0.04 for all samples which indicates good wear resistance. Despite being dual phase (α’+β) all compositions present elastic modulus that are considerably lower than those of commercial Ti alloys currently used (above 100 GPa).

Abstract: The need for biomaterials is increasing as more and more health problems become more and more complex. Progress in the field of medical biomaterials is also accelerating, but the provision of renewable biomaterials continues to be of concern to the world as awareness of sustainable development in the field of chemistry and health. Various strategies in the development of medical biomaterials were studied through a narrative review of the literature. One of them is the strategy of developing inorganic-organic hybrid medical biomaterials through the cultivation of silkworms as producers of renewable biomaterial raw materials. Sericulture can produce active biomaterials such as sericin, fibroin and other renewable materials and those biomaterials can be combined with inorganic nanoparticles to produce medical functional biomaterials on an ongoing basis. The addition of antibacterial bioactive materials such as natural dyestuffs and inorganic nanoparticles of anti-bacterial agents can increase the productivity and quality of antimicrobial biomaterials produced by the cultivation of silkworms.

Abstract: The Ecuadorian paper industry faces the constant challenge of seeking alternative raw materials to replace wood pulp in paper production and its derivatives to reduce production costs. Therefore, this study aims to evaluate the quality properties of paper derived from bacterial cellulose from two of Ecuador's most abundant agricultural residues: banana peels and pineapple peels. The influence of the productivity parameters of the bacterial cellulose produced on the quality properties of the derived paper is established using multivariate statistical methodologies. Fifteen treatments with different carbon sources in the microorganism's culture medium were applied: medium with glucose (T1), media with banana peel extracts at various concentrations (T2-T8), and media with pineapple peel extracts at various concentrations (T9-T15). After obtaining the cellulose, additives and coating solutions were added to produce paper. The results showed that high concentrations of banana peel extracts (T5-T8) were significantly related to the weight and yield of bacterial cellulose, as well as the grammage and water content of the paper. This demonstrates that the quality of bacterial cellulose and the nutritional composition of banana peel extracts are optimal for efficient and sustainable paper production.

Abstract: Collagen has been widely used in biomedical applications, mainly to develop structures (cell scaffolds) that allow cell growth and differentiation processes. This biomolecule is also used in cosmetics because it is an essential ingredient of certain makeup and in pharmaceutics for bandages to treat wounds and burns. However, the use of collagen has been limited by the ethical and moral implications of the (typically animal) sources from which it is extracted. Therefore, alternative, more environmentally friendly sources should be found to obtain collagen. Extracting collagen from fishing industry waste (such as scales, bones, and fish skin) has been presented as an advantageous alternative to obtain this biomaterial, which has also shown promising results due to its biocompatibility with human structures (organs and tissues). The characteristics of this molecule and other sources from which it can be obtained should be further studied.

Abstract: This study focuses on the performance and mechanical characteristics response of pure Canola oil and Canola oil with existence of Hyaluronic Acid. Numerous studies show that plant-based substances are infrequently used in synthetic synovial fluid. The sort of bio-fluid that derives from plant-based oil and can function as a synthetic synovial fluid is the focus of this work. Three samples of a bio-fluid made of Canola oil with three different concentrations of Hyaluronic Acid (HA) are 0 ml, 5 ml, and 10ml, respectively. The 500 mm x 500 mm x 4 mm Polylactic Acid (PLA) biomaterial disc was chosen in the pin on disc wear and friction test rig experiment in conjunction with a canola-based oil tested lubricant to simulate the mechanical principles on the knee. To obtain accurate findings for the wear rate and friction coefficient, the samples will be put through a tribology test. The experiment was conducted to measure the tribology of the stainless pin to observe the effect of coefficient of friction and wear rate on the pin. The reliable outcome may open up new avenues for future research on synthetic synovial fluid. On the other hand, this study is beneficial to medical technology for future treatment of any diseases related to synovial fluid and allows the manufacturer to improve understanding in the optimization of these lubricants in ensuring a long-term application in the human body.

Abstract: Titanium and its alloys are potential candidates widely used to manufacture medical implants. In spite of possessing excellent properties suitable for a biomaterial, Ti suffers from lack of ability to bond with the local tissue termed as “bioactivity”. Several strategies have been adopted to increase the bioactivity of titanium for bone implant applications. Micro arc oxidation (MAO) is one of such promising surface treatments which produces an oxide layer on the surface of Ti which promote better tissue interactions at the surface Ti. Hence, in the present work, commercial pure Ti (CP-Ti) has been treated with MAO process and the produced surface was characterized to study the oxide layer developed on the Ti surface. X-Ray diffraction studies demonstrated the formation of TiO₂ layer on the surface of CP-Ti. Scanning electron microscope images and EDS analysis confirms the porosity in the produced oxide layer which is favorable towards better cell interactions. The presence of considerable amount of phosphorous in the oxide layer which is form the electrolyte used during MAO process was also observed. The preliminary findings demonstrate the simple and effective way to produce porous oxide layer on Ti for biomedical applications.

Abstract: Treatment of rich chromium effluent is a matter of concern in many leather industries. Nano zero valent iron (NZI) is considered as one of the promising adsorbent materials due to its large surface area. Also, biomaterials have great remediation efficiency because of their surface-active groups such as hydroxyl and carboxyl groups. In this paper, we study the use of nano-bio polymer complex (NBPC) in chromium removal. Batch experiments were carried out in terms of operating medium pH, contact times, initial chromium concentrations, and speed rates. The maximum chromium removal of 88% was observed at pH values 7.0, contact time 30 min, and speed rate 150 rpm for chromium concentration 100 mg/L. The adsorption linear isotherms fitted well to Freundlich’s model compared to Langmuir’s model. Treatment of tannery wastewater through NBPC beads showed a decrease in heavy metal concentrations at equilibrium with removal orders of Mn > Cu > Ni > Cr > Pb > Fe > Cd. The removal efficiency of chromium ions is 52% with specific uptake of 25.6 mg(Cr)/g(NBPC). Results showed a decrease in the organic loads represented in COD, BOD, ammonia nitrogen, nitrate, and phosphorous with removal efficiencies 51.8, 48.6, 66.1, 63, and 43.3%, respectively. The reusability of NBPC beads was studied for three subsequent cycles. Results revealed that the availability of NBPC beads for reuse but with removal efficiencies is less than that of the first cycle. X-ray diffraction, SEM micrograph with EDAX analysis, and FT-IR spectroscopy for NBPC beads were studied for surface characterizations.

Abstract: Extraction of the natural halal hydroxyapatite (HAp) from fish scale (Black Tilapia) was produced by calcining of raw fish scale at 600 °C and 800 °C. The produced powders were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with an Energy Dispersive Spectroscopy, (EDX). The crystallite size, cell parameters, strain and crystallinity of the raw fish scale and derived HAp calcined powder were observed from the XRD results. By increasing the calcination temperature, the average crystallite size HAp amount increased and close to the pure HAp (JCPDS: 9-432). SEM analysis showed the raw fish scale surface morphology contains collagen fiber compared with boiled and after calcination of the powder samples. The calcined fish scale powders at 800°C morphology was discovered embraced of hexagonal fragments form. The EDX investigation exposed that the fish scale from HAp powder calcined at temperature 600 °C contain a high amount of magnesium and sodium compared to the powder that was calcined at 800 °C.