Hank's Balanced Salt Solution Research Articles

In vitro immersion study and characterization of biomimetic bovine hydroxyapatite scaffolds: Influence of calcination temperature (600 and 1000 °C) on apatite formation

This work reports on the properties of natural bovine hydroxyapatite (HAp) scaffolds calcined at temperatures of 600 and 1000 °C and on the effects of apatite formation on these calcined scaffolds during immersion experiments in Hank's Balanced Salt Solution (HBSS) from 0 to 28 days. The study systematically identifies different mechanisms that determine the formation of the apatite layer. First, compositional analysis of the scaffolds by inductively couple plasma (ICP) reveals significant differences in macromineral content, which includes calcium, phosphorus, magnesium, and sodium. Subsequent X-ray diffraction (XRD) analysis reveals the presence of hydroxyapatite in both scaffolds, while the 1000 °C sample has additional β-whitlockite due to the higher calcination temperature. Further investigation by Fourier Transform Infrared Spectroscopy (FTIR) and Raman analyzes revealed carbonated HAp in the 600 °C scaffolds and characteristic bands of HAp in the 1000 °C scaffolds. Morphological changes during immersion, documented by Scanning Electron Microscopy (SEM) images, display leaf-like and cauliflower-like structures in the 600 °C sample and rash-like features leading to leaf-type apatite formation in the 1000 °C sample. High-Resolution Transmission Electron Microscopy (HR-TEM) showed elongated crystals in both samples, confirming exclusive HAp presence in the 600 °C sample and the coexistence of HAp and β-whitlockite phases in the 1000 °C sample. After 28 days of immersion, TEM images at 600 °C reveal ordered apatite particles, while the 1000 °C images exhibit random apatite formation, confirmed by Energy Dispersive X-ray Spectroscopy in TEM (EDS-TEM). In addition, both scaffolds calcined at 600 and 1000 °C showed biocompatibility, as cytotoxicity tests confirmed a remarkable 100 % cell viability, underlining their non-toxicity. The scaffolds calcined at 600 and 1000 °C therefore exhibit high bioactivity and viability, supporting their suitability for bone tissue engineering applications.

A Comparative Evaluation of the Periodontal Ligament Cell Viability Using Placentrex, Propolis, and Hanks' Balanced Salt Solution: An In-Vitro Study.

Most of the dento-alveolar trauma that occurs frequently in childhood is often linked to avulsion injuries. Two considerable elements influencing the prognosis of tooth avulsion after replantation are extraoral dry duration and the characteristics of the storage media to support the viability of cells. The study aimed to compare and assess the effectiveness of Hanks' balanced salt solution (HBSS) (HiMedia Laboratories, Thane, India) and Placentrex (Albert David Limited, Kolkata, India) against propolis (5% and 10%) as storage media in preserving the vitality of periodontal ligament (PDL) cells. Four groups with 15 samples each were selected for the study. Sixty recently extracted premolars were left to incubate for 30 minutes in 15-ml falcon tubes containing 2.5 ml of collagenase 0.2 mg/ml in phosphate-buffered saline and 2.4 mg/ml of dispase in HBSS, Placentex, propolis 5%, and propolis 10%. After the addition of bovine serum, it was centrifuged for 4 minutes. Trypan blue 0.4% was utilized to recognize the cells, and a hemocytometer was employed for counting the live PDL cells under a light microscope. Propolis 5% and 10%, HBSS, and Placentrex all showed statistically significant differences in PDL cell viability; however, HBSS was significantly outperformed by Placentrex and propolis. Placentrex is a superior substitute storage medium in cases of tooth avulsion as opposed to alternatives such as propolis 5% and 10%.

The Probiotic Lactobacillus reuteri Preferentially Synthesizes Kynurenic Acid from Kynurenine.

The gut-brain axis is increasingly understood to play a role in neuropsychiatric disorders. The probiotic bacterium Lactobacillus (L.) reuteri and products of tryptophan degradation, specifically the neuroactive kynurenine pathway (KP) metabolite kynurenic acid (KYNA), have received special attention in this context. We, therefore, assessed relevant features of KP metabolism, namely, the cellular uptake of the pivotal metabolite kynurenine and its conversion to its primary products KYNA, 3-hydroxykynurenine and anthranilic acid in L. reuteri by incubating the bacteria in Hank's Balanced Salt solution in vitro. Kynurenine readily entered the bacterial cells and was preferentially converted to KYNA, which was promptly released into the extracellular milieu. De novo production of KYNA increased linearly with increasing concentrations of kynurenine (up to 1 mM) and bacteria (107 to 109 CFU/mL) and with incubation time (1-3 h). KYNA neosynthesis was blocked by two selective inhibitors of mammalian kynurenine aminotransferase II (PF-048559989 and BFF-122). In contrast to mammals, however, kynurenine uptake was not influenced by other substrates of the mammalian large neutral amino acid transporter, and KYNA production was not affected by the presumed competitive enzyme substrates (glutamine and α-aminoadipate). Taken together, these results reveal substantive qualitative differences between bacterial and mammalian KP metabolism.

Evaluation of Corrosion Performance of AZ31 Mg Alloy in Physiological and Highly Corrosive Solutions.

Resorbable Mg and Mg alloys have gained significant interest as promising biomedical materials. However, corrosion of these alloys can lead to premature reduction in their mechanical properties, and therefore their corrosion rate needs to be controlled. The aim of this study is to select an appropriate environment where the effects of coatings on the corrosion rate of the underlying Mg alloy can be discerned and measured in a relatively short time period. The corrosion resistance of uncoated AZ31 alloy in different solutions [Hank's Balanced Salt Solution, 1× phosphate buffered solution (PBS), 4× PBS, 0.9%, 3.5%, and 5 M sodium chloride (NaCl)] was determined by measuring the weight loss over a 2 week period. Upon exposure to physiological solutions, the uncoated AZ31 alloys exhibited a variable weight increase of 0.4 ± 0.4%. 3.5% and 5 M NaCl solutions led to 0.27 and 9.7 mm/year corrosion rates, respectively, where the compositions of corrosion products from AZ31 in all saline solutions were similar. However, the corrosion of the AZ31 alloy when coated by electrochemical oxidation with two phosphate coatings, one containing fluorine (PF) and another containing both fluorine and silica (PFS), showed 0.3 and 0.25 mm/year corrosion rates, respectively. This is more than 30 times lower than that of the uncoated alloy (7.8 mm/year), making them promising candidates for corrosion protection in severe corrosive environments. Cross-sections of the samples showed that the coatings protected the alloy from corrosion by preventing access of saline to the alloy surface, and this was further reinforced by corrosion products from both the alloy and the coatings forming an additional barrier. The information in this paper provides a methodology for evaluating the effects of coatings on the rate of corrosion of magnesium alloys.

Bio-corrosion susceptibility of surface voids and pores in microwave sintered Ti-HAp based bio-composites

Deterioration of implants caused by human blood plasma and liquid influence is termed Bio-corrosion. It is detrimental for metal-based implants to function and affects their lifespan adversely. Hybrid-microwave sintered Titanium-Hydroxyapatite-based metal-ceramic composites were studied for corrosion behaviour in Hank's Balanced Salt solution using an electrochemical test in linear polarization potential mode. The sintering induces surface voids and pores, thus its influence on corrosion for Ti-HAp sintered composite was studied. Different corrosion characteristics were determined, and the corrosion sites were analyzed using SEM-EDS. The study could lead to the development of corrosion-resistant porous bio-implants under an actual physiological body-fluid environment.

A Microfluidic-Fabricated Rod Sprayer for Nanoelectrospray Mass Spectrometry.

The nanoelectrosprayer is a key device in the hyphenation of nanoLC-ESI-MS, and its development plays a crucial role in pushing forward the mining depth of biological discovery and industrialization of omics science. In this work, a new type of nanoelectrospray emitter, a rod sprayer, was developed based on microfluidic manufacture. Due to its porous silica structure, the rod sprayer in effect worked as a multinozzle sprayer, which is composed of a bunch of micrometer sized spray channels. Without the need for sophisticated microfabrication equipment, a superclean environment, or a complicated assembling process, such sprayer rods can be facilely fabricated in a mass production style: 3,600 rods with excellent monodispersity have been fabricated in 1 h, and rod sprayers thus made have demonstrated excellent intraday, interday, and interbatch reproducibilities: RSD = 1.9, 4.9, and 6.1%, respectively. The rod sprayer can generate stable electrospray in a wide voltage range from 2.6 to 3.2 kV and flow rates from 50 to 1000 nL/min, covering typical flow rates of subnanoLC, nanoLC, to microLC, and work steadily even under complex matrix environments (e.g., Hank's balanced salt solution containing sodium, magnesium, and calcium ions) without clogging. Meanwhile, the rod sprayers exhibited 200-1800% ionization efficiency enhancement in comparison with commonly used tapered tip emitters, for small molecule drugs, peptides, and proteins, respectively, and provided a broadened linear dynamic range of 4 orders of magnitude. The excellent characteristics of the rod sprayer, together with its small size and mass production capacity, should provide a high quality, high durability, high consistency, and disposable use-supported nanoelectrospray solution for MS-based bioanalyses.

Drug solubility in biorelevant media in the context of an inhalation-based biopharmaceutics classification system (iBCS)

An inhalation-based Biopharmaceutics Classification System for pulmonary drugs (iBCS) holds the perspective to allow for scientifically sound prediction of differences in the in vivo performance of orally inhaled drug products (OIDPs).A set of nine drug substances were selected, that are administered via both the oral and pulmonary routes. Their solubility was determined in media representative for the oral (Fasted State Simulated Intestinal Fluid (FaSSIF)) and pulmonary (Alveofact medium and Simulated Lung Fluid (SLF)) routes of administration to confirm the need for a novel approach for inhaled drugs. The complexity of these media was then stepwise reduced with the purpose of understanding the contribution of their components to the solubilizing capacity of the media. A second reason for varying the complexity was to identify a medium that would allow robust but accurate dissolution testing. Hence, Hank’s balanced salt solution (HBSS) as a medium used in many in vitro biological tests, non-buffered saline solution, and water were included.For some drug substances (salbutamol sulfate, tobramycin, isoniazid, and tiotropium bromide), no significant differences were observed between the solubility in the media used. For other drugs, however, we observed either just small (rifampicin, budesonide, salmeterol) or unexpectedly large differences (beclomethasone dipropionate).Based on the minimum theoretical solubility required for their common pulmonary dose in 10 ml of lung lining fluid, drug solubility was classified as either high or low. Two high solubility and two low solubility compounds were then selected for refined solubility testing in pulmonary relevant media by varying their content of phospholipids, surfactant proteins and other proteins.The solubility of drug substances in simulated lung lining fluids was found to be dependent on the physicochemical properties of the drug substance and the composition of the media. While a pulmonary dissolution medium that would fit all drugs could not be established, our approach may provide guidance for finding the most suitable dissolution medium for a given drug substance and better designing in vitro tests for predicting the in vivo performance of inhalable drug products.

Anticorrosive properties of chitosan-derivatives coatings on Mg AZ31 alloy in Hank's Balanced Salt Solution

This study describes the preparation of chitosan-derivatives coatings on AZ31 Mg alloy for corrosion protection in Hank's Balanced Salt Solution (HBSS). The derivatives were prepared by reacting chitosan with natural aldehydes (vanillin, benzaldehyde and cinnamaldehyde) and the coatings were characterized by means of water contact angle, scanning electron microscopy and swelling essays. The corrosion behavior of the samples was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy and hydrogen evolution essays. All derivatives present superior corrosion protection than neat chitosan and the best performance is observed for the vanillin derivative with the highest modification degree, which present hydrogen evolution rate of 0.05 mL cm−2 day−1, below the tolerance limit for biomedical application, and |Z|max in the order of 104.6 Ω cm2 even after 14 days of exposure to the corrosive solution.

Establishment of a Practical Sperm Cryopreservation Pathway for the Axolotl (Ambystoma mexicanum): A Community-Level Approach to Germplasm Repository Development.

The axolotl (Ambystoma mexicanum) draws great attention around the world for its importance as a biomedical research model, but housing and maintaining live animals is increasingly expensive and risky as new transgenic lines are developed. The goal of this work was to develop an initial practical pathway for sperm cryopreservation to support germplasm repository development. The present study assembled a pathway through the investigation of axolotl sperm collection by stripping, refrigerated storage in various osmotic pressures, cryopreservation in various cryoprotectants, and in vitro fertilization using thawed sperm. By the stripping of males, 25-800 µL of sperm fluid was collected at concentrations of 1.6 × 106 to 8.9 × 107 sperm/mL. Sperm remained motile for 5 d in Hanks' Balanced Salt Solution (HBSS) at osmolalities of 100-600 mOsm/kg. Sperm cryopreserved in 0.25 mL French straws at 20 °C/min in a final concentration of 5% DMFA plus 200 mM trehalose and thawed at 25 °C for 15 s resulted in 52 ± 12% total post-thaw motility. In six in vitro fertilization trials, 20% of eggs tested with thawed sperm continued to develop to stage 7-8 after 24 h, and a third of those embryos (58) hatched. This work is the first report of successful production of axolotl offspring with cryopreserved sperm, providing a general framework for pathway development to establish Ambystoma germplasm repositories for future research and applications.

Efficacy of Natural Coconut Water, Pre-packaged Coconut Water, and Hank’s Balanced Salt Solution as Storage Media in Maintaining Periodontal Ligament Cell Viability: An In-vitro Study

Introduction: Avulsion of teeth is one of the most complex forms of dental injury, and the selection of an appropriate storage medium greatly influences the preservation of Periodontal Ligament (PDL) cell viability, which is crucial for the successful re-implantation of avulsed teeth. Therefore, identifying effective storage options such as natural coconut water and prepackaged coconut water holds significant promise in improving outcomes for this challenging dental injury. Aim: To evaluate the efficacy of natural coconut water, prepackaged coconut water, and Hank’s Balanced Salt Solution (HBSS) as storage media in maintaining PDL cell viability. Materials and Methods: A total of 32 non-carious freshly extracted human premolars were randomly divided into four study groups (n=8) and stored in the following storage media respectively: Group I-Natural coconut water group, Group IIPre-packaged coconut water group, Group III-Bench dry group, and Group IV-HBSS groups for 30 minutes. The PDL cells were collected and incubated in phosphate buffer saline for 30 minutes and then centrifuged at 800 rpm for five minutes. Following this, the cells were stained with trypan blue to observe their viability. The Analysis of Variance (ANOVA) with Tukey’s post-hoc test was used for analysing the data. Results: The mean percentage of viable cells in natural coconut water (80.6250) was higher than in HBSS (79.8750), prepackaged coconut water (79.2500), and the bench dry group (6.1250). Meanwhile, the mean percentage of non-viable cells was highest in the bench dry group (93.8750), followed by the pre-packaged coconut water (20.7500), HBSS (20.1250), and natural coconut water (19.3750). Conclusion: Natural coconut water and pre-packaged coconut water are equally effective in maintaining the viability of PDL cells. Therefore, pre-packaged coconut water can be used as a substitute for natural coconut water for tooth storage, depending upon availability.

The impact of acemannan, an extracted product from Aloe vera, on proliferation of dental pulp stem cells and healing of mandibular defects in rabbits.

Dental pulp stem cells (DPSCs) were shown to play an important role in regenerative medicine including reconstruction of various bone lesions. This study determined the impact of acemannan, an extracted product from Aloe vera, on in vitro proliferation of DPSCs and in vivo healing of mandibular defects in rabbits. DPSCs were isolated and characterized. The growth kinetics of cells exposed to acemannan (8 mg/mL) and Hank's balanced salt solution (HBSS) were compared in vitro. Fifteen male rabbits were divided into 3 groups. Five animals were left as control group without any therapeutic intervention. Five rabbits were considered as experimental group 1 and received 20 µL of a cell suspension containing 106 DPSCs in the bone defect. Another 5 rabbits were regarded as experimental group 2 and were injected in the bone defect with 20 µL of a cell suspension containing 106 DPSCs treated with acemannan for 24 h. After 60 days, the animals were assessed by radiography and histologically. The mesenchymal properties of DPSCs were confirmed. Population doubling time (PDT) of DPSCs treated with acemannan (29.8 h) was significantly shorter than cells were just exposed to HBSS (45.9 h). DPSCs together with acemannan could significantly accelerate the healing process and osteogenesis in mandibular defects. As DPSCS showed an increased proliferation when treated with acemannan and accelerated the healing process in mandibular defects, these findings can open a new avenue in dentistry regenerative medicine when remedies of bone defects are targeted.

Effect of gamma irradiation and supercritical carbon dioxide sterilization with Novakill™ or ethanol on the fracture toughness of cortical bone.

Sterilization of structural bone allografts is a critical process prior to their clinical use in large cortical bone defects. Gamma irradiation protocols are known to affect tissue integrity in a dose dependent manner. Alternative sterilization treatments, such as supercritical carbon dioxide (SCCO2 ), are gaining popularity due to advantages such as minimal exposure to denaturants, the lack of toxic residues, superior tissue penetration, and minor impacts on mechanical properties including strength and stiffness. The impact of SCCO2 on the fracture toughness of bone tissue, however, remains unknown. Here, we evaluate crack initiation and growth toughness after 2, 6, and 24 h SCCO2 -treatment using Novakill™ and ethanol as additives on ~11 samples per group obtained from a pair of femur diaphyses of a canine. All mechanical testing was performed at ambient air after 24 h soaking in Hanks' balanced salt solution (HBSS). Results show no statistically significant difference in the failure characteristics of the Novakill™-treated groups whereas crack growth toughness after 6 and 24 h of treatment with ethanol significantly increases by 37% (p = .010) and 34% (p = .038), respectively, compared to an untreated control group. In contrast, standard 25 kGy gamma irradiation causes significantly reduced crack growth resistance by 40% (p = .007) compared to untreated bone. FTIR vibrational spectroscopy, conducted after testing, reveals a consistent trend of statistically significant differences (p < .001) with fracture toughness. These trends align with variations in the ratios of enzymatic mature to immature crosslinks in the collagen structure, suggesting a potential association with fracture toughness. Additional Raman spectroscopy after testing shows a similar trend with statistically significant differences (p < .005), which further supports that collagen structural changes occur in the SCF-treated groups with ethanol after 6 and 24 h. Our work reveals the benefits of SCCO2 sterilization compared to gamma irradiation.

Investigation of the electrochemical behavior of a newly designed TiMg dental implant

This study is aimed to evaluate the galvanic corrosion of a newly designed TiMg dental implant. The TiMg composite was tested in two forms: (1) cylinders (TiMg cyl) and (2) dental implants (TiMg DI). Surface roughness was measured using a confocal microscope. The electrochemical behavior was determined in a Hank’s balanced salt solution (HBSS) by the open-circuit potential (OCP), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) measurements. Surfaces after corrosion were examined by a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (EDS). OCP of TiMg cyl and TiMg DI increased in the noble direction, indicating the formation and growth of a base film on their surfaces. After 2-h immersion, TiMg cyl had higher values of iCorr and RCorr compared with those of TiMg DI. After 24-h immersion, a prominent reduction in the values of iCorr and RCorr was observed, and ECorr shifted positively. The Nyquist plots of TiMg cyl and TiMg DI show capacitive loops that tended to close after 2-h exposure. As the time extended, TiMg DI showed higher corrosion resistance compared with that of TiMg cyl, and the linear diffusion response arose from the formation and dissolution of chemically non-stable by-products caused by the hydrogen evolution. In such a case, the involved reaction was controlled by charge transfer and diffusion processes. The formation of a film composed of stable CAp species that attached directly to the surface and chemically non-stable by-products that included (Mg3(PO4)2) and Mg(OH)2 was demonstrated. To conclude, the obtained results revealed that TiMg DI of a complicated threaded design had a more stable passive film and higher corrosion resistance in HBSS compared with those of TiMg cyl of a cylindrical design. These findings have the utmost importance for the fabrication of dental implants.Graphical abstract

Short-Term Storage of Japanese Koi (Cyprinus carpio var. koi) Sperm on the Egg Fertilization Performance

Lack of mature male broodfish, insufficient sperm, and non-synchronized maturation times have always been a hindrance to the breeding program of Japanese koi (Cyprinus carpio var. koi) raised indoors. Therefore, it is believed that the preservation of Japanese koi sperm by short-term storage and cryopreservation could solve this problem. In this study, the appropriate diluent solution, sperm-to-diluent ratio, and storage temperature for short-term storage of Japanese koi sperm were determined, and the efficacy of the short-term stored sperm in fertilizing eggs was evaluated. Milt samples collected from sexually mature males were pooled and tested in modified calcium-free Hank's Balanced Salt Solution (CF-HBSS), modified Mahseer extender, and modified Kurokura extender at 1:1 and 1:5 ratios of sperm to diluent, respectively. Storage temperatures were tested at 4 °C and room temperature. Milt sample without diluent solution served as a control. The percentage of sperm motility was measured daily for one week. For the egg fertilization experiment, Japanese koi eggs were fertilized with sperm on the second day of short-term storage, while a freshly collected sperm sample served as a control. We found that sperm diluted 1:1 with a modified Kurokura extender and stored at 4 °C had a mean sperm motility of 76.00 ± 3.06% on the third day, compared with 54.67 ± 2.91% in the control treatment (P&lt;0.05). Short-term stored spermatozoa showed equivalent egg fertilization ability compared to fresh spermatozoa (control) (P&gt;0.05). In conclusion, the use of a modified Kurokura extender at a 1:1 ratio of sperm to diluent and storage at 4 °C was optimal for short-term storage of Japanese koi sperm, and these sperm still showed equivalent egg fertilization ability to freshly collected sperm after two days of storage. In addition, the current study also determined the appropriate extender solution for cryopreservation of Japanese koi sperm.

Viability of periodontal ligament cells in selected transport media for avulsed teeth

To compare the viability of periodontal ligament (PDL) cells stored in Hanks Balanced Salt Solution (HBSS) with those in readily available transport media over a variable period of time. Methods: Periodontal ligament cells harvested from premolars freshly extracted for orthodontic reasons were cultured for exponential growth. The cells were exposed to egg white, evaporated milk, water and Hanks Balanced Salt Solution (HBSS) at room temperature. Their viability was evaluated after 30 minutes, 1 hour and 3 hours with the tetrazolium salt-based colorimetric assay (MTT assay). Statistical analysis was done using the IBM® SPSS version 23.0 software. Comparison between the Mean Optical Densities (MODs) of the cells stored in HBSS and other media at each time interval was done using the independent t test. Repeated measure ANOVA and Tukey post-hoc test were also carried out to compare the MOD of cells within each medium over time. The level of significance was set at p &lt;0.05. Result: The PDL cells stored in egg white had higher MODs than those in HBSS at 30 minutes and 1 hour. Conversely, the MODs of the cells stored in milk and water were lower than those in HBSS at all the studied points. There was a significant difference in the viability of the cells stored in HBSS and water at all the time points (p&lt;0.05). Conclusion: For up to an hour, egg white was found to perform better than HBSS in supporting the viability of PDL cells.

Multifunctional poly(allylamine hydrochloride)/bioactive glass layer by layer surface coating on magnesium alloy for biomedical applications

The present study reports on a novel multilayer coating for biodegradable magnesium (Mg) alloy substrates. This coating contains soy protein hydrolysate (SPH), poly(allylamine hydrochloride) (PAH), and folic acid (FA) templated bioactive glass (BG) nano particles. The multilayer, designated as SPH/(PAH/BG)n, was coated onto an alkaline-treated Mg alloy surface (AMgS) through a dip-coating process with various numbers of cycles (n = 5and 7) using a layer-by-layer (LbL) assembly. The BG particles had an average diameter of 12.53 ± 2.22 nm and were embedded with therapeutic FA molecules. Scratch testing, wettability, and roughness tests showed excellent adherence of the SPH/(PAH/BG)7 coating on AMgS, making it suitable for cell attachment. Electrochemical measurements in Hanks balanced salt solution (HBSS) demonstrated that the SPH/(PAH/BG)7 coating improved the corrosion resistance of the Mg alloy. SPH/(PAH/BG)7 coated substrate showed a maximum protective efficacy of 98.4041 %, thanks to the bioactive nature of BG. High-resolution XPS and XRD analyses on SPH/(PAH/BG)7/AMgS confirmed the corrosion deposition of Mg(OH)2, MgHPO4.H2O, CaHPO4.H2O, SiO2, MgCO3 and CaCO3 on the substrate surface after immersion in HBSS for 10 d at 37 °C. The LbL coated Mg substrate also showed excellent cytocompatibility by hemolysis assay These results suggest that the SPH/(PAH/BG)7/AMgS material has multifunctional properties and can be a possible alternative for biomedical applications of Mg alloys.

Effects of surface treatments of bioactive tricalcium silicate-based restorative material on the bond strength to resin composite

ObjectivesThis study aimed to enhance the bond strength between Biodentine™ (BD), a bioactive tricalcium silicate (C3S) based material, and resin composite through various surface treatments. MethodologyBD samples were immersed in either double distilled water or Hank's Balanced Salt Solution and analyzed using X-ray Diffraction (XRD). Shear bond strength (SBS) evaluations of BD were performed using Prime & Bond™ NT (PNT), Single Bond Universal (SBU), Xeno V (Xeno), and glass ionomer cement (GIC) following various etching durations (0 s/ 15 s/ 30 s/ 60 s with 37.5% phosphoric acid). Two primers, RelyX™ Ceramic Primer (RCP) and Monobond ™ Plus (MBP), were chosen to prime BD for SBS enhancement. Fractography and bonding interfaces were examined with energy dispersive X-ray spectroscopy (EDS)/ scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). ResultsXRD confirmed BD’s main compositions as C3S, Ca(OH)2, CaCO3 and ZrO2 after 14 days crystal maturation. Etched BD did not improve SBS. GIC exhibited the lowest SBS (p < 0.05) among all adhesives, regardless of the etching mode (all < 1 MPa). The highest SBS (17.5 ± 3.6 MPa, p < 0.05) was achieved when BD primed with MBP followed by SBU application. FTIR and EDS showed γ-MPTS and10-MDP within the MBP primer interacted with C3S and ZrO2 of BD, achieving enhanced SBS. Most specimens exhibited mixed or cohesive failure modes.SignificanceBD’s subpar mechanical properties and texture may contribute to its poor adhesion to resin composite. Pretreating BD with MBP primer, followed by SBU adhesive is recommended for improving bond strength.

Corrosion behavior and microstructure of the surface corrosion film of biodegradable WE43 and ZX21 Mg alloys in Hanks’ balanced salt solution

In this study, the corrosion behavior and microstructure of the surface corrosion film of WE43 (Mg-4 wt%Y-3 wt%RE) and ZX21 (Mg-2 wt%Zn-1 wt%Ca) Mg alloys immersed in Hanks’ balanced salt solution (HBSS) at 37 °C are investigated. Through cross-sectional transmission electron microscopy (TEM) analysis, the surface corrosion films formed on both alloys after immersion in HBSS for 24 h are mainly a mixture of magnesium hydroxide (Mg(OH)2) and dicalcium phosphate dihydrate (DCPD) (CaHPO4·2H2O). Nevertheless, the surface corrosion film on WE43 alloy is only 114 ± 17 nm with Ca and P enriched in the outer portion of the film, while the surface corrosion film on ZX21 alloy is thicker (406 ± 50 nm) with some scattered hollow corrosion products on top of the film. The difference in the surface corrosion film thickness and microstructure is because of the faster corrosion rate of the ZX21 alloy, which resulted from the occurrence of localized corrosion on the alloy surface.

Guttapercha Improves In Vitro Bioactivity and Dentin Remineralization Ability of a Bioglass Containing Polydimethylsiloxane-Based Root Canal Sealer.

Guttapercha (GP, trans-1,4-polyisoprene) is the most used tooth root filling material, and it must be used with an appropriate cement (typically a polydimethylsiloxane (PDMS)-based sealer) to ensure an adequate canal obturation. This study aimed to assess the bioactivity and dentin remineralization ability of a bioglass containing PDMS commercial endodontic sealer, BG-PDMS (GuttaFlow Bioseal), and to evaluate the possible influence of a GP cone (Roeko GP point) on the mineralization process. To this end, BG-PDMS disks were aged alone or in the presence of a GP cone in Hank's Balanced Salt Solution (28 d, 37 °C). Dentin remineralization experiments were carried out under the same conditions. Micro-Raman and IR analyses demonstrated that BG-PDMS is bioactive, thanks to the formation of a silica-rich layer with nucleation sites for B-type carbonated apatite deposition. This phase was thicker when BG-PDMS was aged in the presence of GP. The two materials influenced each other because GP, which alone did not show any bioactivity, nucleated a calcium phosphate phase under these conditions. Analogously, dentin remineralization experiments showed that BG-PDMS is able to remineralize dentin, especially in the presence of GP. Under the experimental conditions, GP acted as a templating agent for calcium phosphate deposition.

Zein-Bioactive Glass nanocomposite Coating on Magnesium Alloy Substrate for Orthopedic Applications

Excellent mechanical strength and biodegradable characteristics of magnesium alloys have sparked considerable interest in orthopedic applications. The utilization of magnesium alloys in orthopedic applications has been restricted due to their brittleness caused by high corrosion rate in biological environments. One of the best techniques for increasing corrosion resistance of these alloys is surface coating. For the first time, the present work aims to dip-coat zein-bioactive glass (BG) nanocomposite on AZ31B magnesium alloy. The alloy surface was also coated by native zein as a control coating. BG nanoparticles required for zein and BG (zein_BG) composite were synthesized by a bio-inspired method using cetyltrimethylammonium bromide (CTAB) as a template. The formation of BG particles was affirmed by FTIR showing characteristic Si-O-Si and Si-O– peaks. Nano-size of BG particles with an average diameter of 6.67 ± 0.06 nm was reported by TEM. SEM micrographs revealed successful deposition of zein and zein_BG coatings on the magnesium alloy surfaces. High-resolution XPS analysis on zein_BG-coated Mg alloy immersed in HBSS revealed the corrosion deposition of Mg(OH)2, MgHPO4.H2O, CaHPO4.H2O, SiO2, MgCO3, and CaCO3 on the substrate surface. More than twofold wettability, 95% adhesion strength and 14-fold increase in surface roughness were reported for zein_BG-coated magnesium alloy compared to the bare surface. Measurements of weight loss in zein and zein_BG-coated alloy substrates in Hanks Balanced Salt Solution (HBSS) for 10 d at 37°C showed a drastic decrease in weight loss of substrates after coating. As a result, zein_BG-coated substrate was observed to possess the maximum protective efficacy (95.99%) against corrosion. Interestingly, electrochemical measurements revealed a vast decrease in corrosion current density (2.41 E−6 A.cm−2) of zein_BG-coated substrate compared to the uncoated substrate (3.04 E−4 A.cm−2). Electrochemical impedance spectra (EIS) confirmed capacitive behavior of zein_BG-coated alloy substrate. These findings demonstrated that simple zein_BG composite dip coating was a successful corrosion-resistant implant coating on magnesium alloy surface for orthopedic applications.