Materials For Medical Applications Research Articles

Mechanical Properties and Residual Stress Measurements of Grade IV Titanium and Ti-6Al-4V and Ti-13Nb-13Zr Titanium Alloys after Laser Treatment.

Nowadays, surface engineering focuses on research into materials for medical applications. Titanium and its alloys are prominent, especially Ti-6Al-4V and Ti-13Nb-13Zr. Samples made of pure grade IV titanium and the titanium alloys Ti-6Al-4V and Ti-13Nb-13Zr were modified via laser treatment with laser beam frequency f = 25 Hz and laser beam power P = 1000 W during a laser pulse with duration t = 1 ms. Subsequently, to analyze the properties of the obtained surface layers, the following tests were performed: scanning electron microscopy, chemical and phase composition analysis, wetting angle tests and roughness tests. The assessment of the impact of the laser modification on the internal stresses of the investigated materials was carried out by comparing the values of the stresses of the laser-modified samples to those of the reference samples. The obtained results showed increased values of tensile stresses after laser modification: the highest value was found for the Ti-6Al-4V alloy at 6.7434 GPa and the lowest for pure grade IV titanium at 3.742 GPa. After laser and heat treatment, a reduction in the stress was observed, together with a significant increase in the hardness of the tested materials, with the highest value for Ti-6Al-4V alloy at 27.723 GPa. This can provide better abrasion resistance and lower long-term toxicity, both of which are desirable when using Ti-6Al-4V and Ti-13Nb-13Zr alloys for implant materials.

Knitted cardiac mesh to support left ventricular hypertrophy: an in vivo experimental study: supporting left ventricular hypertrophy using cardiac support mesh

Purpose The purpose of this work is to perform an application study on experimental animals (dogs) to investigate the efficiency of using weft knitted mesh fabric as cardiac support mesh to support left ventricular hypertrophy. Design/methodology/approach In this work, weft-knitted mesh sample “Knitted Cardiac Support Mesh” manufactured using Nylon (6, 6) yarns, with count 20 Denier and medium mesh size, was placed around the two ventricles to prevent further dilatation, support and reduce left ventricular wall stress. Findings Medical textile is a rapidly expanding field in technical textiles that are widely used in a variety of medical applications. One of these medical textile applications is “Knitted Cardiac Support Mesh”, which is used in the treatment of Dilated Cardiomyopathy. Originality/value After the implantation of the manufactured Knitted Cardiac Support Mesh around the myocardium, all dogs survived for three months before being euthanized, and some clinical examinations were performed to investigate and evaluate the sample performance. It was demonstrated from the experimental application, that the nylon mesh sample performed the best during the surgical operation due to its good ability to stretch and recover at a moderate rate, as well as the textile mesh lightweight.

Antibacterial Activity of Biodegradable Plastic from Chromolaena odorata (Pokok Kapal Terbang) Leaves

The aim of this research project was to develop antimicrobial films from blends of C. odorata and PVA and test the films for microbial activity using broth dilution methods for Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. The result shows that CO/PVA80 successfully inhibit the growth of target bacteria. In antibacterial activity analysis, CO/PVA80 showed 50% higher compare with pure PVA film, PVA100. Other than that, the high percentage of PVA in the blend films, the greater the thickness, Tensile Strength (TS) and Young’s Modulus (YM), while the Elongation Break (EB) of the prepared films decreased. The 0.5 mm CO/PVA80 film shows a good result in mechanical properties which is TS 6.55 MPa, YM 182 MPa and EB is 7.47%. A CO/PVA80 were show a smooth texture, lacked of macropore and good characteristic with a SEM analysis. These results suggest that CO/PVA80 films have good compatibility to form an antimicrobial film as a new material for medical application especially for wound healing.

Formation of diamond like carbon films on materials for medical application

The aim of this experimental work is to identify how the surfaces of materials that are most often used inmedical implants and prostheses, affect the properties of the deposited amorphous carbon films. The DLCfilms were formed on the stainless steel, aluminium, polyetheretherketone (PEEK) and polycaprolactone(PCL) surfaces by PECVD method using C2H2 gas plasma and their properties was compared with the filmsdeposited on silicon. The differences of the films properties were determined by a null-ellipsometry and Ramanspectroscopy. It was found that the thicknesses of the carbon coatings deposited on metallic substratesare larger than on the silicon when the deposition conditions were the same. When the films are formed athigh bias voltage the refractive index of the DLC films deposited on stainless steel are lower compared tothe coatings on silicon but the extinction coefficients are higher. Raman spectra shows that sp2 bonds concentrationis higher in this case. When the ion energy is lowest (bias voltage -400 V), Raman spectroscopyshows that D peak isn’t observed on the Si-deposited carbon coating, while the typical carbon amorphouscoating is formed on the Al substrate. The thickness of amorphous carbon coatings deposited on the polymersdepends on the bias voltage, and the optical properties depend on the type of polymer. The coatingsdeposited on PCL have a much higher refractive index than on PEEK. Key words: amorphous carbon films, steel, aluminum, polyetheretherketone, polycaprolactone, Ramanspectroscopy.

Preparation and Electron-Beam Surface Modification of Novel TiNi Material for Medical Applications

A new approach to fabricate TiNi surfaces combining the advantages of both monolithic and porous materials for implants is used in this work. New materials were obtained by depositing a porous TiNi powder onto monolithic TiNi plates followed by sintering at 1200 °C. Then, further modification of the material surface with a high-current-pulsed electron beam (HCPEB) was carried out. Three materials obtained (one after sintering and two after subsequent beam treatment by 30 pulses with different pulse energy) were studied by XRD, SEM, EDX, surface profilometry, and by means of electrochemical measurements, including OCP and EIS. Structural and compositional changes caused by HCPEB treatment were investigated. Surface properties of the samples during their storage in saline for 10 days were studied and a model experiment with cell growth (MCF-7) was carried out for the unmodified sample with an electron beam to detect cell appearance on different surface locations.

Characterization of a natural surfactant from an essential oil from neem (Azadirachta indica A. Juss) for textile industry applications

Surfactants are multipurpose active compounds and are ubiquitously present in detergents. Detergent demand spiked due to the current COVID-19 pandemic, further alerting to the need to replace petrochemical synthetic surfactants with natural and renewable surfactants to mitigate further environmental damage. The neem tree ( Azadirachta indica A. Juss) is a fast-growing tree that provides a multitude of commodities, namely neem oil. Neem oil possesses insecticidal and medicinal activity. This work reports the extraction and characterization of a surfactant from neem oil (SNO), displaying a yield of approximately 100%. SNO exhibited suitable detergent characteristics with a high potential to be used as a cleansing agent for textile applications, such as high pH value (10.1), suitable foaming of 1.5 cm and a critical micelle concentration of nearly 0.12 g mL−1. In addition, SNO showed a moderate bactericidal activity against Escherichia coli and bacteriostatic activity against Staphylococcus aureus, both common nosocomial pathogens. Therefore, SNO has a good potential to be used in medical textile applications due to its detergent and bactericidal properties. Finally, an economical overview of the SNO production process was assessed, underscoring its viability.

Spectroscopic studies of UV-irradiated poly(vinyl alcohol)/elastin blends

The blends of synthetic and natural polymers are extensively investigated as materials for medical applications. Synthetic component usually ensures appropriate mechanical and physical properties while biopolymer improves biocompatibility of the material. In our work, we decided to use poly(vinyl alcohol) (PVA)—water-soluble, chemically stable, elastic polymer and elastin—a fibrous protein present in the extracellular matrix of connective tissues. The aim of our work was to study the influence of UV light on spectroscopic properties of poly(vinyl alcohol)/elastin hydrolysates blends. PVA is a rather photostable polymer while elastin possesses various chromophores in the structure capable of absorption of light λ > 200 nm. As a result of the blending, some interactions between the synthetic and biological components occur and cause the changes of photochemical stability of the new material. Our study demonstrates that the poly(vinyl alcohol)/elastin mixtures are more sensitive to UV irradiation than both components separately.

A Review on Gelatin Based Hydrogels for Medical Textile Applications

Hydrogels are hydrophilic polymer networks that absorb any kind of liquid including biological fluids. Natural polymers and their derivatives along with synthetic polymers are used to form the hydrogels. Networks that constitute the hydrogels are created by the crosslinking of either synthesized polymers starting from monomers or already developed polymers. Crosslinking can be developed either physically if secondary intermolecular forces are involved or chemically in which a covalent bond between polymeric chains is created. Gelatins are natural driven protein polymers. One of the main biopolymers used for producing hydrogels is gelatin. Gelatin has a very wide application other than hydrogels. In this review, hydrogels and their property and synthesis mechanism, as well as their application in biomedical along with gelatin chemistry and application, are reviewed. Due to its nonimmunogenicity, nontoxicity, low cost, and high availability gelatin-based hydrogels could find applications in drug delivery carrier, bioink, transdermal therapy, wound healing, and tissue repair. The beneficiation of gelatin can result in their sustainable conversion into high-value biomaterials on the proviso of the existence or development of cost-effective, sustainable technologies for converting this biopolymer into useful bioproducts.

Comparative analysis of total phenolic content and antimicrobial activity of some plants of Garo hills, Meghalaya

Eethanolic and aqueous extracts of some plants commonly found in Garo hills of Meghalaya and known for their medicinal value were analysed for total phenolic content and antimicrobial activity. Total content of phenols was quantitatively estimated from extracts of lemon grass, tamarind, Ber, starfruit and Beetle nut. Antimicrobial activity and yield of these plant extracts was also determined. Further, ethanolic extracts have revealed better total phenolic content and antimicrobial activity against test pathogens in comparison to aqueous extracts. Among the plant extracts investigated Beetle nut exhibited highest content of phenols and also best antimicrobial properties. The results show that use of the natural antimicrobial inherent properties occurring in plants extracts is a viable option for the textile finishing industry for functional textile applications. The plant extracts showed high antimicrobial activity which indicates that these extracts may be useful natural remedies for antimicrobial textile finishes for treatment of various types of skin/wound infections and medical textile applications.

Processing of Highly Filled Polymer-Metal Feedstocks for Fused Filament Fabrication and the Production of Metallic Implants.

Fused filament fabrication (FFF) is a new procedure for the production of plastic parts, particularly if the parts have a complex geometry and are only needed in a limited quantity, e.g., in specific medical applications. In addition to the production of parts which are purely composed of polymers, fused filament fabrication can be successfully applied for the preparation of green bodies for sintering of metallic implant materials in medical applications. In this case, highly filled polymer–metal feedstocks, which contain a variety of polymeric components, are used. In this study, we focus on various polymer-metal feedstocks, investigate the rheological properties of these materials, and relate them to our results of FFF experiments. Small amplitudes of shear oscillations reveal that the linear range of the polymer–metal feedstocks under investigation is very small, which is caused by elastic and viscous interactions between the metallic particles. These interactions strongly influence or even dominate the flow properties of the feedstock depending on the applied shear stress. The magnitude of the complex viscosity strongly increases with decreasing angular frequency, which indicates the existence of an apparent yield stress. The viscosity increase caused by the high powder loading needed for sintering limits the maximum printing velocity and the minimum layer height. The apparent yield stress hinders the formation of smooth surfaces in the FFF process and slows down the welding of deposited layers. The influence of composition on the processing parameters (suitable temperature range) and part properties (e.g., surface roughness) is discussed on the basis of rheological data.

Strategies for improving antimicrobial properties of stainless steel.

In this review, strategies for improving the antimicrobial properties of stainless steel (SS) are presented. The main focus given is to present current strategies for surface modification of SS, which alter surface characteristics in terms of surface chemistry, topography and wettability/surface charge, without influencing the bulk attributes of the material. As SS exhibits excellent mechanical properties and satisfactory biocompatibility, it is one of the most frequently used materials in medical applications. It is widely used as a material for fabricating orthopedic prosthesis, cardiovascular stents/valves and recently also for three dimensional (3D) printing of custom made implants. Despite its good mechanical properties, SS lacks desired biofunctionality, which makes it prone to bacterial adhesion and biofilm formation. Due to increased resistance of bacteria to antibiotics, it is imperative to achieve antibacterial properties of implants. Thus, many different approaches were proposed and are discussed herein. Emphasis is given on novel approaches based on treatment with highly reactive plasma, which may alter SS topography, chemistry and wettability under appropriate treatment conditions. This review aims to present and critically discuss different approaches and propose novel possibilities for surface modification of SS by using highly reactive gaseous plasma in order to obtain a desired biological response.

Usage of glass ionomer cements for reconstructions in the head region

Glass ionomer cements are a two-component hybrid material, consisting of inorganic glass particles, surrounded by an insoluble hydrogel matrix. They are a group of materials based on the acid/ base reaction between poly (alkenoic) acid and an ion-leachable silicate glass. Their biocompatibility, osteoconductive behavior, and ability to bond to bone and metals have generated interest in the material for medical applications. GIC are widely used in dental medicine as an obturation material in primary teeth for treatment and prophylaxis of dental caries, because they have the ability to create a physicochemical bond to tooth structure and to release fluoride. They are currently frequently used in otological and neuro-otological surgery. Apart from ossicular chain reconstruction, they are used for repair of tegmen defects, outer ear canal reconstruction, mastoid obli teration, and stabilization of some hearing prostheses.

Recombinant Spidroins as the Basis for New Materials.

Spider web proteins are unique materials created by nature that, considering the combination of their properties, do not have analogues among natural or human-created materials. Obtaining significant amounts of these proteins from natural sources is not feasible. Biotechnological manufacturing in heterological systems is complicated by the very high molecular weight of spidroins and their specific amino acid composition. Obtaining recombinant analogues of spidroins in heterological systems, mainly in bacteria and yeast, has become a compromise solution. Because they can self-assemble, these proteins can form various materials, such as fibers, films, 3D-foams, hydrogels, tubes, and microcapsules. The effectiveness of spidroin hydrogels in deep wound healing, as 3D scaffolds for bone tissue regeneration and as oriented fibers for axon growth and nerve tissue regeneration, was demonstrated in animal models. The possibility to use spidroin micro- and nanoparticles for drug delivery was demonstrated, including the use of modified spidroins for virus-free DNA delivery into animal cell nuclei. In the past few years, significant interest has arisen concerning the use of these materials as biocompatible and biodegradable soft optics to construct photonic crystal super lenses and fiber optics and as soft electronics to use in triboelectric nanogenerators. This review summarizes the latest achievements in the field of spidroin production, the creation of materials based on them, the study of these materials as a scaffold for the growth, proliferation, and differentiation of various types of cells, and the prospects for using these materials for medical applications (e.g., tissue engineering, drug delivery, coating medical devices), soft optics, and electronics. Accumulated data suggest the use of recombinant spidroins in medical practice in the near future.

Tribological and Mechanical Behaviour of the Polymer Matrix Composite Reinforced with Ceramics Used as Implant Material

Recently, leading to its various attractive properties, Polymer matrix composites are suitable material in medical applications. This includes a light weight to high strength, a simple and complex shape easy to process. This paper describes the effect of Alumina, CaCO3, and TiO2 reinforcements with bio polymer UHMWPE matrix. The samples were fabricated by injection molding machines with different particle reinforcement percentages. On prepared samples, various experiments have been carried out, viz tensile, bending, impact, hardness, and wear. Samples were developed according to the ASTM standard. Polymer matrix composites of 65% LDPE + 5% TiO2 + 15% Al2O3 + 15% CaCO3 is suitable biomaterial candidate. Thus, it can be used in an orthopedic approach applied on hard or soft tissues.

The interplay between network morphology and degradation kinetics of polymers: Theoretical and experimental analysis by means of a 2D model system

ABSTRACTNetwork formation by cross-linking is a common method to incorporate functions like elastic deformability, shape-memory capability or hydrogel formation into polymer materials for medical applications. Since these materials are often intended to degrade, their design would benefit from a quantitative prediction of the interdependence between network architecture and degradation behavior. Here, we introduce a quantitative description of the degradation behavior of polymer networks. A simplified model was developed under the assumption of having an ideal network, where all network strands are terminated by network nodes and each node is connected to the same number of strands. To describe the degradation of real networks, the model was modified by allowing for a varying connectivity of network nodes, which also included free chain-ends. The models were validated by comparison with Langmuir monolayer degradation data from 2D networks formed by cross-linking oligo(ε-caprolactone)diols with dialdehydes. We found that both the ideal network hypothesis and the real network model were in excellent agreement with the experimental data, with the ideal network hypothesis requiring longer network strands than the real network to result in the same degradation behavior. The models were further used to calculate the degradation curves of the corresponding, non cross-linked molecules. By comparison, it was found that the network formation increases the time required to reach 50% degradation of oligo(ε-caprolactone)diols by only 20%. This difference mainly arises from attaching free chain ends to network points.

Development and Characterization of Wound Dressing Material Coated with Natural Extracts of Curcumin, Aloe vera and Chitosan Solution Enhanced with rhEGF (REGEN-DTM)

ABSTRACT In this work, the leave extracts of Aloe vera, piper betel and neem leaf were prepared and coated on bamboo fiber based material for wound dressing applications. The fabrics coated with different compositions of the natural extract were enhanced with rhEGF (REGEN-D™ 150). The FTIR confirms the presence of alcoholic and phenolic group which were responsible for antibacterial activity. The SEM morphology of the developed dressing material was porous nature and more suitable for the process of curing wound. In antimicrobial tests, the zone of incubation of E. coli and S. aureus ranges from 18 mm and 22. In vivo study using albino rats induced with diabetes reveals that the wound healing rate is increased in the range of 25% to 54% compared to a negative-control group. Overall, the natural extracts coated dressing material has considerable potential and well suited for clinical application that was evidenced through antimicrobial and in vivo study results. Therefore, natural extracts coated on bamboo-based dressing materials are claimed to have helpful nature for wound healing and the current study will be one of the platforms for natural extracts coated material-based medical textile applications.

Poly(Methyl Methacrylate) Structure Modification through Zn-Cu-In-S / ZnS Quantum Dot Nanocrystals Dispersion

The aim of the current study was to present a simple method for the fabrication of quantum dot (QD)/polymer films for possible use as a luminescent material in medical applications. To this aim the poly(methyl methacrylate) (PMMA) polymer matrix was modified in order to host Zinc Copper Indium Sulfide encapsulated by an outer core of Zinc Sulfide (ZnCuInS/ZnS) QD nanocrystals, through dispersion. Four composite PMMA films of ZnCuInS/ZnS nanocrystals with maximum emission at 530 nm and concentrations of 1.0, 4.0, 6.0 and 10.0 %w/v, were prepared. X-ray irradiation and scanning electron microscopy (SEM) micrographs were used to evaluate the volume homogeneity of the final samples, as a measure of QD dispersion. The coefficient of variation (CV) estimated from homogeneity measurements, increased with increasing concentration, for the 1.0, 4.0 and 6.0 %w/v samples. The minimum CV value was obtained for the 10.0 %w/v sample which is attributed to the incorporation of sonication in the final product, during the fabrication process. Homogenous dispersion was observed from the SEM micrographs.

Fabrication of a multifunctional magnetic-fluorescent material for medical applications.

Multifunctional biocompatible materials have evoked considerable interest in the field of medical applications. Here we report the thermal decomposition preparation of homogeneous fluorescent-magnetic particles with a composite structure containing CoFe2O4 nanoparticles as nucleation seeds for fluorescent Gd2-xO3:Eux. The composite exhibited a wide range of fluorescence transitions in the whole visible spectrum, displaying 18 different emission peaks when excited at a 250 nm wavelength. Moreover, at low temperature the peaks of the composite were wider than the peaks of the fluorescent material, which may be attributed to a set of new energy levels due to a combination of Stark splitting with the magnetic field of CoFe2O4. Because this material is intended to be used for biomedical applications, the potential toxicity of the composite was tested using an invertebrate hemocyte cell model. The cells showed slight morphological and biochemical changes upon exposure to the composite; however, there was no increase in cell death at concentrations of up to 40 ppm. In addition, the material could be tracked by its fluorescence inside the cells, when excited at a more bio-friendly and less energetic wavelength of 405 nm. Furthermore, MRI showed T1 and T2 dual contrast with relaxivity values in the range of most reported materials.

Triclosan applications for biocidal functionalization of polyester and cotton surfaces

For 20 years, antibacterial functionalization has been one of the most attractive research fields in the textile industry. Nowadays, globalization has spread the microorganisms everywhere and produced many epidemics and pandemics such as smallpox, cholera, tuberculosis, yellow fever, Spanish flu, and coronavirus. The textile materials treated with triclosan would be a strong alternative to obtain antibacterial function against microorganisms for the medical applications, such as face masks, lab coats, and wound dresses. This study aimed to investigate the characterization, antibacterial properties, and durability of triclosan on polyester, polyester/cotton, and cotton surfaces. The pure triclosan and presence of triclosan in solutions were detected by gas chromatography–mass spectrometry chromatograms. It can be seen that surfaces were homogeneously covered by triclosan on scanning electron microscope micrographs, and there were new bands on Fourier transform infrared spectra after treatments. Large inhibition zones around all surfaces were observed, and antibacterial activity slightly increased depending on increasing chemical concentrations. The samples demonstrated strong biocidal activity to bacteria for 3 h. They lost their antibacterial properties after washing, but they showed good antibacterial (bactericidal) properties and satisfactory durability to washes. The results show that triclosan is a highly effective and durable chemical on polyester and cotton surfaces for medical textile applications.

Influence of ionic liquid on graphite/silver nanoparticles dispersion and antibacterial properties against Escherichia coli of PP/EPDM composite coatings

ABSTRACTIn this work, graphite doped with silver nanoparticles are synthesized and coated onto a PP/EPDM blend surface. Three nanoparticles deposition methods are used. In one method, the nanoparticles are directly deposited on previously corona discharge‐treated TPO surface. Another method is by compression deposition of nanoparticles in a thin layer forming a segregated coating. In the last method, a nanoparticle‐polymer composite is deposited and then treated by corona discharge to expose the deposited nanoparticles. These last two methods show excellent antimicrobial activity (R = 2.8 and 3.9, respectively) and higher inhibition values (85% and 89%, respectively) against Escherichia coli strains. The effect of using HMIMPF6 and BMIMBF4 ionic liquids on particle dispersion and antibacterial activity against E. coli is evaluated. Using ionic liquids enhance the antibacterial activity (from R = 3.9 to 5.4) and inhibition rates (from 89% to 99.8%) of the samples. As a result, a thermoplastic elastomer (TPE) material with enhanced antibacterial properties against E. coli is obtained using ionic liquids, which offer significant promise as a material for medical applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48714.