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Herein, the tribological behavior of 316L stainless steel (SS) fabricated using metal extrusion additive manufacturing (MEAM) is investigated both under dry and simulated body fluid (SBF)‐lubricated conditions. The results and mechanisms are compared with those of 316L SS fabricated via selective laser melting (SLM) and hot rolling (HR). Under dry‐friction conditions, the 316L SS fabricated via MEAM shows inferior tribological performance compared with those fabricated via SLM and HR, primarily because of its lower initial hardness and better plasticity, which increase both abrasive and adhesive wear. Under SBF‐lubricated conditions, the tribological performance of the 316L SS fabricated via MEAM is comparable to that fabricated via HR and superior to that fabricated via SLM. The wear rate of the MEAM‐fabricated 316L SS is 16.8% and 3.2% lower than SLM‐ and HR‐fabricated, respectively. The numerous pores on 316L SS serve as traps for wear particles, which contribute to the reduction of three‐body wear. In terms of wear under SBF‐lubricated conditions, MEAM technology appears to be a promising method for the fabrication of customized 316L orthopedic implants. [ABSTRACT FROM AUTHOR]

AZ80 magnesium alloy was surface treated by micro‐arc oxidation (MAO) and composite of laser shock penning (LSP) and MAO techniques. Untreated and treated specimens were pre‐corroded in simulated body fluids (SBF) with different pH values (pH 4, 7.4, and 9). The ratcheting behavior of all test specimens was experimentally investigated under stress‐controlled loading. The positive or negative value of the ratcheting strain reflects the mechanism of cyclic deformation. The ratcheting strain with negative values is associated with the cyclic deformation being dominated by twinning–detwinning, while the ratcheting strain with positive values is due to dislocation slip playing a dominant role in the cyclic deformation. A higher absolute value of the ratcheting strain means a lower the ratcheting life. Single MAO coating is not conducive to the fatigue life of magnesium alloy in acidic SBF environment, while LSP/MAO composite coating can improve the fatigue life of magnesium alloy under various loading conditions and different pH environment. Highlights: Two modified layers were prepared on the surface of AZ80 magnesium alloys.Modified layers and pH values on effect of ratcheting deformation was investigated.Four deformation mechanisms were used to evaluate the ratcheting behavior. [ABSTRACT FROM AUTHOR]

Aerogels are fascinating solid materials known for their highly porous nanostructure and exceptional physical, chemical, and mechanical properties. They show great promise in various technological and biomedical applications, including tissue engineering, and bone and cartilage substitution. To evaluate the bioactivity of bone substitutes, researchers typically conduct in vitro tests using simulated body fluids and specific cell lines, while in vivo testing involves the study of materials in different animal species. In this context, our primary focus is to investigate the applications of different types of aerogels, considering their specific materials, microstructure, and porosity in the field of bone and cartilage tissue engineering. From clinically approved materials to experimental aerogels, we present a comprehensive list and summary of various aerogel building blocks and their biological activities. Additionally, we explore how the complexity of aerogel scaffolds influences their in vivo performance, ranging from simple single-component or hybrid aerogels to more intricate and organized structures. We also discuss commonly used formulation and drying methods in aerogel chemistry, including molding, freeze casting, supercritical foaming, freeze drying, subcritical, and supercritical drying techniques. These techniques play a crucial role in shaping aerogels for specific applications. Alongside the progress made, we acknowledge the challenges ahead and assess the near and far future of aerogel-based hard tissue engineering materials, as well as their potential connection with emerging healing techniques. [ABSTRACT FROM AUTHOR]

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Quantification of Cd2+ release from Cd-containing quantum dots (QDs) is of fundamental importance to elucidate its toxicity to organisms, but remains a great challenge due to the lack of appropriate analytical method. Herein, a facile method based on size exclusion chromatography (SEC) combined with inductively coupled plasma mass spectrometry (ICP-MS) was developed for separating and quantifying the QDs and counterpart ions. By using the mixture of sodium dodecyl sulfate (SDS) and ethylenediaminetetraacetic acid tetrasodium salt (EDTA) as the mobile phase, the defect of QD and ion adsorption onto the SEC column was overcome, thus realizing the accurate quantification of ionic species. Besides, the concentration of QDs was achieved through subtracting the ion concentration from the total concentration. Selecting CdSe@ZnS as the typical QDs, the Cd2+ release process in four typical simulated body fluids, namely, simulated gastric fluid, simulated sweat, Gamble's solution, and artificial lysosomal fluid, was monitored using the developed SEC–ICP–MS method. The media pH is identified as the decisive factor which controls the dissolution of ZnS shells and also the Cd2+ release kinetics and final concentration. Our results suggest that the oral pathway for QD uptake poses the biggest risk to human health. [ABSTRACT FROM AUTHOR]

A novel model of biodegradable PHA copolymer films preparation was applied to evaluate the biodegradability of various PHA copolymers and to discuss its biomedical applicability. In this study, we illustrate the potential biomaterial degradation rate affectability by manipulation of monomer composition via controlling the biosynthetic strategies. Within the experimental investigation, we have prepared two different copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate—P(3HB-co-36 mol.% 4HB) and P(3HB-co-66 mol.% 4HB), by cultivating the thermophilic bacterial strain Aneurinibacillus sp. H1 and further investigated its degradability in simulated body fluids (SBFs). Both copolymers revealed faster weight reduction in synthetic gastric juice (SGJ) and artificial colonic fluid (ACF) than simple homopolymer P3HB. In addition, degradation mechanisms differed across tested polymers, according to SEM micrographs. While incubated in SGJ, samples were fragmented due to fast hydrolysis sourcing from substantially low pH, which suggest abiotic degradation as the major degradation mechanism. On the contrary, ACF incubation indicated obvious enzymatic hydrolysis. Further, no cytotoxicity of the waste fluids was observed on CaCO-2 cell line. Based on these results in combination with high production flexibility, we suggest P(3HB-co-4HB) copolymers produced by Aneurinibacillus sp. H1 as being very auspicious polymers for intestinal in vivo treatments. [ABSTRACT FROM AUTHOR]

Silicone rubber (SR) has extensively been used for different industrial and biomedical applications, in view of its good elasticity, chemical inertness, and biocompatibility. However, cure inhibition features, poor mechanical properties, and hydrophobicity, often, limit the possible expansion of its spectrum of applications. The present work has been designed to address these issues by embedding a potential biocompatible filler, nano‐hydroxylapatite (n‐HA), within the SR matrix, through compression molding. The n‐HA particles were initially synthesized by a wet chemical method, and were subsequently introduced into SR quantitatively. The rheological features, compressive properties, simulated body fluid (SBF) uptake, bovine serum albumin (BSA) adsorption, blood compatibility, and cytocompatibility of n‐HA modified SR systems have been investigated. The change in rheological characteristics after n‐HA embedding within SR clearly indicated the favorable interactions between them, and a compatible functional existence under external stresses. The compressive strength, which is critical for the different applications of SR, has been found to be increased with an increase in n‐HA loading. In‐vitro mineralization studies using SBF showed the formation of apatite crystals on the surface of SR/n‐HA system indicating its biocompatibility. This has been confirmed by SEM and FTIR examinations. It has further been observed that the addition of n‐HA particles into SR matrix enhances the protein adsorption characteristics. The n‐HA embedded system exhibited excellent blood compatibility, which has been complemented through hemolysis (%) studies and thrombogenicity assay. The results indicate that the strategy of n‐HA embedding would do significant value addition to SR, and widen its scope in the industrial and biomedical sectors. [ABSTRACT FROM AUTHOR]

Purpose: The commercial stainless steels have been used extensively in the biomedicine application and their electrochemical behaviour in the simulated body fluid (SBF) are not uncovered obviously. In this research, the corrosion resistance of the commercial stainless steel of Fe–17Cr–xNi alloys (x = 4, 8, 10 and 14) has been studied. This study aims to evaluate the rate of corrosion and corrosion resistance of some Fe–Cr–Ni alloys in SBF at 37°C. Design/methodology/approach: In this research, the corrosion resistance of the commercial stainless steel of Fe–17Cr–xNi alloys has been studied using open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization in the SBF at 37°C and pH 7.4 for a week. Also, the surface morphology of the four alloys was investigated using scanning electron microscopy, elemental composition was obtained via energy dispersive spectroscopy and the crystal lattice structure of Fe–17Cr–xNi alloys was obtained using X-ray diffraction technique. The chemical structure of the protective oxide film has been examined by X-ray photoelectron spectroscopy (XPS) and metals ions released into the solution have been detected after different immersion time using atomic absorption spectroscopy. Findings: The results revealed that the increase of the Ni content leads to the formation of the stable protective film on the alloys such as the Fe–17Cr–10Ni and Fe–17Cr–14Ni alloys which possess solid solution properties. The Fe–17Cr–14Ni alloy displayed highest resistance of corrosion, notable resistance for localized corrosion and the low corrosion rate in SBF because of the formation of a homogenously protective oxide film on the surface. The XPS analysis showed that the elemental Fe, Cr and Ni react with the electrolyte medium and the passive film is mainly composed of Cr2O3 with some amounts of Fe(II) hydroxide at pH 7.4. Originality/value: This work includes important investigation to use commercial stainless steel alloys for biomedical application. [ABSTRACT FROM AUTHOR]

Characteristics of phenanthrene and pyrene's sorption and desorption on two local soils in solutions of simulated groundwater, simulated lung fluid, and simulated saliva were studied with batch equilibrium experiments to understand the fate of PAHs in the karst region of southwestern China and to assess the environmental exposure and the health risk of PAHs. The results showed that the sorption and desorption isotherms of phenanthrene and pyrene on two target soils in the three solution systems could be adequately described by the Freundlich model, while the fitted isotherm parameters for the simulated groundwater solution distinguished notably from those for the simulated body fluid solutions. For the sorption experiments, in the simulated groundwater, the n values were 0.722 and 0.672 for phenanthrene and were 0.724 and 0.663 for pyrene, respectively, on the yellow soil and the limestone soil; The log KF values were 3.118 and 3.323 for phenanthrene and were 3.648 and 3.846 for pyrene, respectively, on the yellow soil and the limestone soil. In the simulated body fluids, the n values for phenanthrene and pyrene ranged from 0.622 to 0.836 and from 0.590 to 0.865, respectively, and the log KF values of phenanthrene and pyrene ranged from 2.845 to 3.327 and from 3.344 to 3.779, respectively. For the desorption experiments, in the simulated groundwater, the n values were 0.662 and 0.744 for phenanthrene and were 0.702 and 0.647 for pyrene, respectively, on the yellow soil and the limestone soil. The log KF values were 3.666 and 3.686 for phenanthrene and were 4.128 and 4.225 for pyrene, respectively, on the yellow soil and the limestone soil. In the simulated body fluids, the n values for phenanthrene and pyrene ranged from 0.612 to 0.668 and from 0.631 to 0.819, respectively, and the log KF values of phenanthrene and pyrene ranged from 3.134 to 3.407 and from 3.533 to 3.839, respectively. The limestone soil had relatively higher log KF values but lower KOC values compared to those of the yellow soil, indicated that the nature of sorbent soils played the dominant role in sorption and desorption behaviors of PAHs. The experimental results showed a remarkable differences in sorption and desorption behaviors of PAHs in simulated body fluids and groundwater. The nonlinearities of measured isotherms and the measured sorption capacities of soils in simulated body fluids were significantly lower than corresponding those in the simulated groundwater, and HI values for simulated body fluids systems were significantly smaller than corresponding those for the simulated groundwater systems. The results underscore cautions in assessing environmental exposure and health risks of PAHs based on their sorption–desorption data in simulated groundwater as this is traditionally done. [ABSTRACT FROM AUTHOR]

Purpose: Most of the studies concerning gellan have been focused on its application as a food ingredient, however, gellan is often considered as a candidate for the development of novel pharmaceutical formulations. Taking into account that gellan is ion-sensitive, it can be assumed that its initial mechanical properties can change upon contact with body secretions. Therefore, the aim of the work was to investigate the rheological properties of pure high-acyl gellan gum hydrogel (0.4%) and its mixtures with selected simulated body fluids. Methods: The rheological investigations were performed on rotational rheometer and included oscillatory temperature, amplitude, and frequency sweeping. The results enabled estimation of the linear viscoelastic regime, calculation of the cross-over points, and percentage of structure recovery. Results: In the case of pure hydrogel no evidence of thermosensitivity was observed in the range of 20-40[sup °]C. In pH = 1.2 (NaCl/HCl) the hydrogel structure was almost entirely destroyed. Mixing with phosphate buffer (pH = 4.5) resulted in higher gel strength than after dilution with deionized water. The opposite effect was observed in the case of pH = 7.4. The studies performed for the mixture of GG hydrogel and mucin indicated interaction between the components. The hydrogel elasticity increased in the presence of simulated tear, but decreased in simulated saliva and vaginal fluid. Conclusions: In this study, it was shown that the stability of a three-dimensional gellan structure may be affected by pH and the presence of mucin which most probably competed with gellan gum in divalent cations binding. The observations presented in this study may be important in terms of potential application of gellan gum as a potential carrier in drug delivery systems. [ABSTRACT FROM AUTHOR]

The metastable and stable equilibria during the precipitation of calcium phosphates in three biomimetic systems, namely SBFc-CaCl-KHPO-HO, SBFc-CaCl-MgCl-KHPO-HO and SBFc-CaCl-ZnCl-KHPO-HO, where SBFc denotes a conventional simulated body fluid, were modeled by a thermodynamic approach (ion-association model, computer program PHREEQCI v.2.14.3). In all cases the highest saturation indices (SI) and the thermodynamic stability were calculated for hydroxyapatite, Ca(PO)OH. Co-precipitation of metastable phases of seven salts in the first system, co-precipitation of additional four magnesium salts in the second system, and no co-precipitation of zinc salts in the third system were calculated at pH 8. Precipitation of amorphous calcium phosphate incorporating Mg, Na, K, $$ {\text{CO}}_{3}^{2 - } $$ and Cl ions at levels close to those of natural enamel, dentin and bone, instead of the thermodynamically stable hydroxyapatite, was experimentally found. This reveals that kinetic factors are decisive for the precipitation processes. In addition, the phase transformations of the precipitated metastable amorphous products (9.94 > SI > 0) during their maturation in the three simulated body fluids, differing in their concentrations of $$ {\text{HCO}}_{3}^{ - } $$ and Cl ions and organic macromolecules, were also modeled. Dissolution of all magnesium salts was found to occur and equilibrium of the more stable calcium salts was established, depending on the $$ {\text{HCO}}_{3}^{ - } $$ concentration. In contrast, transformation of the stable equilibrium products (SI > 0) to the thermodynamically stable hydroxyapatite (SI = 0), independent of the $$ {\text{HCO}}_{3}^{ - } $$ concentration, was both calculated and experimentally proven. Analogous distribution of the species was calculated for the initial and equilibrium solutions of the studied SBFs, while it was different for the metastable solutions. The predominance of free Me ions (Me = Ca, Mg) was calculated in all studied cases. [ABSTRACT FROM AUTHOR]

The application of mesoporous silica nanoparticles as a platform for drug delivery and bioimaging requires a good understanding of the degradability of these particles under physiological conditions. Optimally, the degradability should be studied in vivo using relevant administration routes and dosings, but such studies are complicated and expensive. Thus, the biodegradability is often studied in vitro using simulated body fluids. However, such studies are scarce to date, and the results are partially conflicting. The aims of this study were therefore (a) to determine the influence of the composition of different simulated body fluids on the observed silica dissolution rates and (b) to establish morphological key parameters that determine the dissolution kinetics of silica nanoparticles. As dissolution media, simulated body fluid (SBF), simulated lung fluid (SLF), simulated gastric juice (SGF) and PBS buffer were used, and the silica concentration was kept below the silica saturation limit. Three mesoporous silica particles of different sizes were studied together with one non-porous Stöber-type silica particle. The observed silica dissolution rates followed the order SLF > SBF ≈ PBS ≫ SGF. Apart from general pH effects, the presence of organic acids in SLF is suggested to enhance the silica dissolution rate. The specific surface area was identified as the main parameter controlling the rate of dissolution of the different silica particles studied, while particle size influences were minor. Graphical Abstract: The dissolution of mesoporous silicas with different particle sizes has been studied in four different physiological buffers. [ABSTRACT FROM AUTHOR]

Although stainless steel is a material widely used for biomedical applications, its surface properties for long term application are still a serious concern. 316L stainless steel (SS 316L) is a material commonly used in dentistry for orthodontic braces, wires and in some cases as dental crowns. The pH value of natural saliva from the oral cavity can undergo sudden modification due to food products which are rich in citric acid. The electrochemical corrosion behavior of 316L stainless steel was evaluated in two simulated body fluid solutions, Fusayama-Mayer artificial saliva with pH=5 and Fusayama-Mayer artificial saliva adjusted with citric acid to a pH=1.58 which simulates the environmental conditions of the oral cavity. The surface of SS316L was investigated by optical microscope before and after corrosion assays. The electrochemical corrosion behavior was studied by open circuit potential, potenitodynamic polarization and linear polarization. Optical microscopy was used to characterize the corrosion damage after the electrochemical assays. [ABSTRACT FROM AUTHOR]

Transient cartilage and a mineralizing microenvironment play pivotal roles in mesenchymal cell ossification during bone formation. In order to recreate these microenvironmental cues, C3H10T1/2 murine mesenchymal stem cells (MSCs) were exposed to chondrocyte-conditioned medium (CM) and seeded onto three-dimensional mineralized scaffolds for bone regeneration. Expansion of C3H10T1/2 cells with CM resulted in enhanced expression levels of chondrogenic markers such as aggrecan, type II collagen, type X collagen, and Sox9, rather than of osteogenic genes. Interestingly, CM expansion led to reduced expression levels of osteogenic genes such as alkaline phosphatase ( ALP), type I collagen, osteocalcin, and Runx2. However, CM-expanded C3H10T1/2 cells showed enhanced osteogenic differentiation as indicated by increased ALP and Alizarin Red S staining upon osteogenic factor exposure. In vivo, CM-expanded C3H10T1/2 mesenchymal cells were seeded onto mineralized scaffolds (fabricated with polydopamine and coated with simulated body fluids) and implanted into critical-sized calvarial-defect mouse models. After 8 weeks of implantation, mouse skulls were collected, and bone tissue regeneration was evaluated by micro-computed tumography and Masson's trichrome staining. In accordance with the in vitro analysis, CM-expanded C3H10T1/2 cells gave enhanced bone mineral deposition. Thus, chondrocyte-conditioned factors and a mineralized microenvironment stimulate the bone formation of MSCs. [ABSTRACT FROM AUTHOR]

The electrochemical corrosion behaviour of biomedical Ti-25Nb-3Mo-3Zr-2Sn (TLM) alloy was investigated in various simulated body fluids at 37±0.5° utilising potentiodynamic polarisation and current-time curves. The Ti-6Al-4V (TC4) alloy was also investigated to make a comparison. The different simulated body fluids comprised of 0.9%NaCl saline, Hank's and Ringer's solution were employed. The effect of heat treatment on the electrochemical behaviour of the TLM alloy was also considered. It was discovered that all the test specimens were passivated once immersed into the simulated body fluids. It was also found that the TLM alloy has poorer corrosion resistance in Hank's solution, due to the chemical composition of the Hank's. After different heat treated, the TLM alloy had different phases and microstr°ture, and the corrosion behaviour of the TLM alloy was different. In this study, after the heat treatment of 760°/1 h/AC+550°/6 h/AC, the TLM alloy had better corrosion resistance. Owing to the corrosion resistance of the TLM alloy was influenced by numerous factors, s°h as microstr°ture and the chemical composition of electrolyte, the corrosion behaviour of the TLM alloy is complex. By comparing with the corrosion behaviour of the TC4 alloy, the TLM alloy has poorer corrosion resistant than the TC4 alloy under the same conditions. But the current-time curves of the TLM alloy were more stable than these of the TC4 alloy with further experiments, because of the more passivation film on the surface of the TLM alloy. [ABSTRACT FROM AUTHOR]

Objective: To determine the micro hardness of novel Pakistani manufactured osteosynthetic titanium bone mini plates (MPP) and imported osteosynthetic titanium bone mini plates (MPG) in body like conditions. Study Design: Descriptive study. Place and Duration of Study: This study was carried out at School of Chemical and Material Engineering, NUST from March to May 2013. Material and Methods: Microvicker hardness tester was used for assessment of micro hardness of two types of plates. The hardness was checked before conditioning and after conditioning at (six different places) on interval of 1, 7,14,21,28 and 40 days in modified simulated body fluid with ph 7.4 and temperature 37°C. Results: Result showed that hardness of MPG was higher than MPP and after conditioning in simulated body fluid at all time periods, hardness of both types of plates was increased. Conclusion: It can be concluded from this study that micro hardness of imported plates is more than local plates so recommendations should be sent to manufacturers of local industry of Pakistan to improve the hardness of local plates so that they can meet international standards. [ABSTRACT FROM AUTHOR]

Biomimetic formation of extracellular matrix (ECM) like coatings on artificial biomaterials provides a promising route to gain bioactive materials for tissue engineering applications. Organic ECM is also a template for apatite mineralization in bone tissue. This study was aimed at designing a multilayer film containing an ECM-like molecule on biomaterial surfaces to direct apatite mineralization and to develop biomimetic biomaterials for bone tissue engineering. A multilayer film consisting of gelatin and poly(ethylenimine) molecules was formed on a poly(L-lactic acid) substrate via electrostatic self-assembly technique. Bone-like apatite coating was formed on the multilayer film modified poly(L-lactic acid) substrate in simulated body fluids (SBFs). The amount of forming apatite could be controlled by the Ca2+ and HPO4 2- concentrations in SBF and also through the mineralization time. Gelatin terminated multilayer film can induce the apatite formation with a weak orientation in the (002) plane and the apatite is similar in composition to the natural bone. The gelatin multilayer film/apatite composite coating may serve as a promising microenvironment for bone tissue formation and growth. [ABSTRACT FROM AUTHOR]

X-ray photoelectron spectroscopy (XPS) is extensively used to characterise the surface of materials used in bioengineering. Its ability to characterise both the elemental composition and structural characteristics of the surface makes it particularly useful, as it can identify the functional groups present on the surface of any material and implicitely give insight into biointerfacial interactions. The paper summarizes some XPS results obtained on compact and porous materials with potential biomedical applications, before and after their interaction with simulated body fluids. [ABSTRACT FROM AUTHOR]

The deposition of a bonelike mineral on the surface of polymer scaffolds results in the formation of hybrid biomaterials, possessing enhanced osteoconductivity while retaining appropriate biodegradability. However, current methods of fabricating such composite scaffolds use a prolonged incubation process, which permits scaffold deformation and premature loss of incorporated macromolecules. We hypothesized that the fabrication of biomineralized polymer scaffolds could be achieved using premineralized polymer microspheres generated through incubation in a modified simulated body fluid (mSBF). We explored the material characteristics of these substrates and characterized the in vitro osteogenic differentiation of human mesenchymal stem cells (hMSCs) when cultured on these novel scaffolds. Unlike scaffolds prepared using the conventional approach, premineralized scaffolds maintained their initial conformation after fabrication, achieved improved mineral distribution throughout the substrate, and enabled significantly greater incorporation efficiency of a model protein. We did not detect differences in osteogenic differentiation as determined by alkaline phosphatase activity and osteopontin secretion. However, we did observe a significant increase in cell-secreted calcium by hMSCs seeded on scaffolds prepared from premineralized polymer. These results demonstrate that the use of premineralized polymeric materials to fabricate biodegradable polymer scaffolds is an improved method for composite scaffold formation and may have numerous advantages for use in bone tissue engineering. [ABSTRACT FROM AUTHOR]

Three simulated body fluids were prepared by varying the magnesium ion content. Ceramic specimens, obtained by uniaxial pressing of wollastonite powders followed by sintering, were immersed in each simulated body fluid for different periods of time at physiological conditions of pH and temperature. In all the cases, an apatite layer was formed on the ceramic specimens. However, the morphology of the layer changed substantially. Furthermore, the crystallinity of the apatite layer decreased as the magnesium content in SBF was increased. [ABSTRACT FROM AUTHOR]

The present paper focuses on the fabrication of coatings based on vinyltrimethoxysilane and the influence of various corrosion media on the coatings produced. Coatings were deposited on two substrate materials, namely, titanium Grade 2 and titanium alloy Ti13Nb13Zr, by immersion in a solution containing vinyltrimethoxysilane, anhydrous ethyl alcohol, acetic acid and distilled water. The obtained coatings were characterized in terms of surface morphology, adhesion to the substrate and corrosion resistance. As corrosion solutions, four different simulated physiological fluids, which differed in the contents of individual ions, and a 1 mol dm−3 NaBr solution were used. The chloride ions contained in the simulated physiological fluids did not lead to pitting corrosion of titanium Grade 2 and titanium alloy Ti13Nb13Zr. This investigation shows that titanium undergoes pitting corrosion in a bromide ion medium. It is demonstrated that the investigated coatings slow down corrosion processes in all corrosion media examined. [ABSTRACT FROM AUTHOR]

Stearic acid-based solid lipid nanoparticles, stabilised with Tween® 20, were synthesised using a microwave-assisted microemulsion technique and their stability was tested in simulated blood plasma, several liquids mimicking gastrointestinal fluids and solutions containing different electrolyte compositions and pH levels. It was discovered that simulated blood plasma had a stabilising effect on the particles, as did simulated saliva and intestinal fluid, which was due to hydration forces, facilitated by the presence of hydrated cations. It was determined that the hydration stabilisation was pH dependent, with highly acidic conditions depriving the solid lipid nanoparticles of the negative charge required for the cations to hydrate the surface. In environments lacking hydrated cations, the particles were predominately reliant on steric stabilisation and were particularly susceptible to pH extremes due to hydrolysis/oxidation of the Tween® 20 layer. The results suggest that the SLNs have potential as a systemic drug carrier, as the physicochemical conditions of blood provide a stabilising environment that inhibits particle growth. [ABSTRACT FROM AUTHOR]