Use In Biomedical Engineering Research Articles

A multiple applications study of motile microorganisms past a vertical surface with double‐diffusive binary base fluid

AbstractThis study investigates the various uses of density of motile microorganisms in the context of the flow of a binary base fluid with double diffusion past a vertical surface. The research aims to comprehend the interactions between motile microorganisms and the fluid dynamics, as well as the heat and mass transport mechanisms in this system. The analysis involves mathematically constructing the governing equations, transforming them into dimensionless nonlinear ordinary differential equations using similarity transformations, and numerically solving them using the MATLAB bvp4c solver. An analysis of the influence of several parameters on the profiles of velocity, temperature, concentration, nanoparticle concentration, and density of motile microorganisms is conducted using graphical representation. The findings demonstrate that boosting the thermophoresis parameter intensifies the temperature profile. In addition, an increase in the nanofluid Schmidt number results in a larger concentration of nanoparticles, whereas a higher bioconvection Lewis number reduces the density of the motile microorganism profile. These findings may find use in biomedical engineering as well as industrial processes that include enhancing the efficiency of mass transfer and bioconvection. Numeric simulation prophesies 99.9% for both shear stress and heat transfer rate intensification for Prandtl values are noticed.

Molecular Dynamic Simulations for Biopolymers with Biomedical Applications.

Computational modeling (CM) is a versatile scientific methodology used to examine the properties and behavior of complex systems, such as polymeric materials for biomedical bioengineering. CM has emerged as a primary tool for predicting, setting up, and interpreting experimental results. Integrating in silico and in vitro experiments accelerates scientific advancements, yielding quicker results at a reduced cost. While CM is a mature discipline, its use in biomedical engineering for biopolymer materials has only recently gained prominence. In biopolymer biomedical engineering, CM focuses on three key research areas: (A) Computer-aided design (CAD/CAM) utilizes specialized software to design and model biopolymers for various biomedical applications. This technology allows researchers to create precise three-dimensional models of biopolymers, taking into account their chemical, structural, and functional properties. These models can be used to enhance the structure of biopolymers and improve their effectiveness in specific medical applications. (B) Finite element analysis, a computational technique used to analyze and solve problems in engineering and physics. This approach divides the physical domain into small finite elements with simple geometric shapes. This computational technique enables the study and understanding of the mechanical and structural behavior of biopolymers in biomedical environments. (C) Molecular dynamics (MD) simulations involve using advanced computational techniques to study the behavior of biopolymers at the molecular and atomic levels. These simulations are fundamental for better understanding biological processes at the molecular level. Studying the wide-ranging uses of MD simulations in biopolymers involves examining the structural, functional, and evolutionary aspects of biomolecular systems over time. MD simulations solve Newton's equations of motion for all-atom systems, producing spatial trajectories for each atom. This provides valuable insights into properties such as water absorption on biopolymer surfaces and interactions with solid surfaces, which are crucial for assessing biomaterials. This review provides a comprehensive overview of the various applications of MD simulations in biopolymers. Additionally, it highlights the flexibility, robustness, and synergistic relationship between in silico and experimental techniques.

Valorization of Crude Glycerol, Residue Deriving from Biodiesel- Production Process, with the Use of Wild-type New Isolated Yarrowia lipolytica Strains: Production of Metabolites with Pharmaceutical and Biotechnological Interest.

Crude glycerol (Glol), used as substrate for screening eleven natural Yarrowia lipolytica strains in shake-flask experiments. Aim of this study was to assess the ability of the screened strains to produce biomass (dry cell weight; X), lipid (L), citric acid (Cit), mannitol (Man), arabitol (Ara) and erythritol (Ery), compounds presenting pharmaceutical and biotechnological interest, in glycerol-based nitrogen-limited media, in which initial glycerol concentration had been adjusted to 40 g/L. Citric acid may find use in biomedical engineering (i.e. drug delivery, tissue engineering, bioimaging, orthopedics, medical device coating, wound dressings). Polyols are considered as compounds with non-cariogenic and less calorigenic properties as also with low insulin-mediated response. Microbial lipids containing polyunsaturated fatty acids (PUFA) are medically and dietetically important (selective pharmaceutical and anticancer properties, aid fetal brain development, the sight function of the eye, hormonal balance and the cardio-vascular system, prevent reasons leading to type-2 diabetes, present healing and anti-inflammatory effects). All strains presented satisfactory microbial growth (Xmax=5.34-6.26 g/L) and almost complete substrate uptake. The principal metabolic product was citric acid (Citmax=8.5-31.7 g/L). Production of cellular lipid reached the values of 0.33-0.84 g/L. Polyols were also synthesized as strain dependent compounds (Manmax=2.8-6.1 g/L, Aramax ~2.0 g/L, Erymax= 0.5-3.8 g/L). The selected Y. lipolytica strain ACA-DC 5029 presented satisfactory growth along with synthesis of citric acid and polyols, thus, was further grown on media presenting an increased concentration of Glol~75 g/L. Biomass, lipid and citric acid production presented significant enhancement (Xmax=11.80 g/L, Lmax=1.26 g/L, Citmax=30.8 g/L), but conversion yield of citric acid produced per glycerol consumed was decreased compared to screening trials. Erythritol secretion (Erymax=15.6 g/L) was highly favored, suggesting a shift of yeast metabolism from citric acid accumulation towards erythritol production. Maximum endopolysaccharides (IPS) concentration was 4.04 g/L with yield in dry weight 34.2 % w/w. Y. lipolytica strain ACA-YC 5029 can be considered as a satisfactory candidate grown in high concentrations of crude glycerol to produce added-value compounds that interest pharmaceutical and biotechnology industries.

Effects of RF plasma modification on the thermal and mechanical properties of electrospun chitosan/poly(vinyl alcohol) nanofiber mats

On the design and fabrication of biomedical devices, the mechanical integrity and the thermal stability of the materials used are of paramount consideration. In this study, the effects of 13.56 MHz radio frequency plasma modification using argon (Ar) and oxygen (O2) discharges on the morphology, thermal properties, and tensile properties of the nonwoven electrospun chitosan/poly(vinyl alcohol) nanofiber mats were investigated. The scanning electron microscope images showed a significant change in the morphology of the nanofiber mats due to the Ar and O2 plasma treatment. The thermogravimetric-differential thermogravimetry data revealed two major degradation steps for both the pristine samples and the Ar plasma-treated samples due to the molecular backbone degradation and decomposition of polyene and carbonyl residues. However, a third peak was observed for O2 plasma-treated samples which may be due to the oxygen functionalities imparted by the discharge as seen from the Fourier-transform infrared spectroscopy data. Differential scanning calorimetry (DSC) results have shown the glass transition temperature at 65–68 °C and a melting temperature at around 200–220 °C. Also, a decrease in the crystallinity of the plasma-treated samples were noted from the DSC thermograms. A significant (p < 0.05) decrease in the tensile strength, yield strength, Young's modulus, and elongation at break were noted for the plasma-treated samples due to the etching and ablation effects induced by energetic particle interactions. However, the mechanical properties are still comparable with the tensile properties of human tissues such as the skin. These nonwoven mats with tunable properties have potential use in biomedical engineering, particularly as tissue scaffolds, wound dressings, sutures, and antibacterial gauzes.

Review article- Role of Chitosan in Wound Healing - a Review of the Recent Advances

During the past decade, much interest has been developed in biopolymer based materials due to their biocompatible, biodegradable, non-toxic and non-allergic nature. Studies have been done on the key features of inherent properties of chitosan, their modification, and its use in biomedical engineering particularly toward anti inflammatory and wound healing. Chitin and chitosan with beneficial biological and antimicrobial properties and high valuable potential for wound healing are attractive for wound care. The chitin nanowhiskers applications are used mainly as reinforcing polymer nanocomposites, but also to prepare scaffolds, hydrogels and wound dressings, as adsorbents in industry, water purification, for protein immobilization, transformation of bacteria by exogenous genes, stabilization of oil-in-water emulsion and nematic gels, formation of CaCO3/chitin-whisker hybrids and as carbon precursors.

Austenitic high interstitial steels vs. CoCrMo – Comparison of fatigue behavior

The favourable combination of strength and ductility as well as excellent corrosion resistance of CrNiCN-austenitic steels is the reason for their use in biomedical engineering. However, Ni was attributed to cause allergies within a certain number of patients. Thus Ni-free alternatives like CoCrMo- and Ti-base alloys are often preferred. Other possible alternatives might be austenitic high nitrogen steels (AHNS) and austenitic high interstitial steels (AHIS). The aim of this study is to compare the fatigue properties of Ni-free austenitic CrMn(Mo)CN-steels with 0.85–1.07wt% C+N, CoCrMo-alloy with up to 0.25wt% C and conventional CrNiCN-steels with 0.01–0.42wt% C+N.The comparison was conducted using total strain controlled axial LCF and HCF fatigue tests at room temperature on solution-annealed samples. After mechanical testing the samples were investigated by means of SEM including EBSD and TEM in order to analyse the distribution of plastic strains.In contrast to the CrNiCN-steels, which show cyclic hardening before the generation of the first crack, the CrMn(Mo)CN as well as the CoCrMo-alloys only showed cyclic softening. Still within the HCF regime the Co-base alloys showed the best fatigue behavior in terms of numbers of cycles to fracture Nf for a given total strain amplitude, while the Ni-free CrMn(Mo)CN-steels were either as good or slightly worse. The results indicate a distinct correlation between slip behavior, stacking fault energy and the amount of interstitials in solid solution.

Thin calcium-phosphate coatings produced by RF magnetron sputtering and prospects for their use in biomedical engineering

Thin calcium-phosphate coatings with thickness less than 2.7 m were prepared by radio-frequency magnetron sputtering technique on the surfaces of pure titanium, titanium alloy Ti6A14V and stainless ASTM 316. Results of scanning electron microscopy showed that all coatings were dense and poreless and did not have any visible defects or microcracks. Rutherford backscattering (RBS) revealed a prepared coating consisting only of calcium 33.6 (1.6 at%, phosphorous 16.5 (1.5 at%, and oxygen 48.6 (1.2 at%. The concentration of each above-mentioned element through the coating was almost constant. The physicomechanical properties of the prepared coatings were investigated using a nanoindentation technique. The values of nano-hardness and Young's modulus calculated on the basis of the obtained data were 10 GPa and 113 GPa, respectively. These values were higher than that of non-coated substrates, except titanium alloy due to the sputtering mechanism. It was found that the coating with a thickness less than 1.6 ?m possessed more adhesion strength than coatings with greater value of thickness. However, we suggest that all coatings have great cohesive resistance that does not depend on the coating thickness.

Tissue regeneration: A new property of mesoporous materials

A new application of mesoporous materials as bone regenerators is described. In vitro bioactivity studies by soaking three different mesoporous materials, SBA-15, MCM-48 and MCM-41, in simulated body fluid (SBF) have been carried out. After the in vitro test, the study by Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, electron diffraction and microscopy shows that an apatite-like layer is formed on the surface of SBA-15 and MCM-48 materials after 30 and 60 days, respectively, allowing their use in biomedical engineering for tissue regeneration.