Hemolysis Ratio Research Articles

Bioresorption Control and Biological Response of Magnesium Alloy AZ31 Coated with Poly-β-Hydroxybutyrate

Magnesium and its alloys are not normally used as bioresorbable temporary implants due to their high and uncontrolled degradation rate in a physiological liquid environment. The improvement of corrosion resistance to simulated body fluids (SBF) of a magnesium alloy (AZ31) coated with poly-β-hydroxybutyrate (PHB) was investigated. Scanning electron microscopy, Fourier transform infrared spectrometer, and contact angle measurements were used to characterize surface morphology, material composition, and wettability, respectively. pH modification of the SBF corroding medium, mass of Mg2+ ions released, weight loss of the samples exposed to the SBF solution, and electrochemical experiments were used to describe the corrosion process and its kinetics. The material’s biocompatibility was described by evaluating the effect of corrosion by products collected in the SBF equilibrating solution on hemolysis ratio, cytotoxicity, nitric oxide (NO), and total antioxidant capacity (T-AOC). The results showed that the PHB coating can diffusively control the degradation rate of magnesium alloy, improving its biocompatibility: the hemolysis rate of materials was lower than 5%, while in vitro human umbilical vein endothelial cell (HUVEC) compatibility experiments showed that PHB-coated Mg alloy promoted cell proliferation and had no effect on the NO content and that the T-AOC was enhanced compared with the normal group and bare AZ31 alloy. PHB-coated AZ31 magnesium alloy extraction fluids have a less toxic behavior due to the lower concentration of corrosion byproducts deriving from the diffusion control exerted by the PHB coating films both from the metal surface to the solution and vice versa. These findings provide more reference value for the selection of such systems as tunable bioresorbable prosthetic materials.

Purified antioxidant from the medicinal mushroom Phellinus pini protects rat H9c2 cell against H2 O2 -induced oxidative stress.

In this study, through the combination of AB-8 macroporous resin, Sephadex LH-20 column chromatography and semi-preparative HPLC, an antioxidant component was purified from the crude extract of Phellinus pini, thereby evaluating the cardioprotective effect of the fraction. As a result, total phenolic content of the 60% ethanol elution was increased by 4.8-fold after one run treatment on Sephadex LH-20 chromatography with gradient elution. After semi-preparative HPLC separation, the first peak (PP-S4-1) showed that inhibition ratio of erythrocyte hemolysis was 91.9%, and inhibition ratio of lipid peroxidation was also increased by 87.6%, at 50μg/ml (p<.01). Based on the results of ESI-MS, 1 HNMR, 13 CNMR, and RP-HPLC compared to many published results, PP-S4-1was identified as catechin (MW 290.015, C15 H14 O6 ). The results showed that PP-S4-1 pretreatment made cell viability increased, and the generation of reactive oxygen species (ROS) inhibited. Meanwhile, PP-S4-1 remarkably decreased the fluorescence intensity of Ca2+ , and increased mitochondrial membrane potential (MMP; ΔΨm). In addition, PP-S4-1 could significantly inhibit the decrease of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activity as well as the increase of MDA content in H9c2 cells induced by H2 O2 . Moreover, pretreatment with PP-S4-1 significantly improved the morphological changes and prevented H2 O2 -induced DNA damage. Therefore, this study clarifies the ability of PP-S4-1 to treat H9c2 cell oxidative stress damage induced by H2 O2 through its antioxidant effect. PRACTICAL APPLICATIONS: This research is not only helpful to elaborate the cardioprotective effect of Phellinus pini but also can contribute to the development of health foods or drug supplements for heart disease in the future. This is the first report dealing with phenolic component and cardioprotective activity of a medicinal mushroom P. pini belonging to the genus Phellinus.

A composite sponge based on alkylated chitosan and diatom-biosilica for rapid hemostasis

Rapid control of bleeding is of great significance in military trauma and traffic accidents. In this study, alkylated chitosan (AC) and diatom biosilica (DB) were combined to develop a safe and effective hemostatic composite sponge (AC-DB sponge) for hemorrhage control. Due to the procoagulant chemical structure of AC-DB sponge, it exhibited rapid hemostatic ability in vitro (clotting time was shortened by 78% than that of control group), with favorable biocompatibility (hemolysis ratio < 5%, no cytotoxicity). The strong interface effect between AC-DB sponge and blood induced the erythrocyte and platelets activation, deformation and aggregation, intrinsic coagulation pathway activation, resulting in significant coagulation acceleration. AC-DB sponge had excellent performance in in vivo assessments with shortest clotting time (106.2 s) and minimal blood loss (328.5 mg). All above results proved that AC-DB sponge had great potential to be a safe and rapid hemostatic material.

Alendronate-Decorated Nanoparticles as Bone-Targeted Alendronate Carriers for Potential Osteoporosis Treatment.

Osteoporosis is a skeletal disorder characterized by a low bone mass and density. Alendronate (Alen), a second-generation bisphosphonate drug, was indicated as the first-line regimen for the treatment of osteoporosis. However, the use of Alen has been limited due to its low bioavailability and gastrointestinal side effects. Herein, Alen-decorated nanoparticles were prepared through ionic cross-linking between poly (lactic-co-glycolic acid), β-cyclodextrin-modified chitosan (PLGA-CS-CD), and Alen-modified alginate (ALG-Alen) for Alen loading and bone-targeted delivery. Alen was selected as a therapeutic drug and a bone-targeting ligand. The nanoparticles have negatively charged surfaces, and sustained release of Alen from the nanoparticles can be observed. Cytotoxicity detected using cell counting kit-8 (CCK-8) assay and lactate dehydrogenase release test on MC3T3 cells showed that the nanoparticles had good cytocompatibility. A hemolysis test showed that the hemolysis ratios of nanoparticles were <5%, indicating that the nanoparticles had no significant hemolysis effect. Moreover, the Alen-decorated nanoparticles exhibited enhanced binding affinity to the hydroxyapatite (HAp) disks compared with that of nanoparticles without Alen modification. Thus, the Alen-decorated nanoparticles might be developed as promising bone-targeted carriers for the treatment of osteoporosis.

Poly(Vinylamine) Derived N-Doped C-Dots with Antimicrobial and Antibiofilm Activities

Nitrogen-doped carbon dots (N-doped C-dots) was synthesized by using poly(vinyl amine) (PVAm) as a nitrogen source and citric acid (CA) as a carbon source via the hydrothermal method. Various weight ratios of CA and PVAm (CA:PVAm) were used to synthesize N-doped C-dots. The N-doped C-dots revealed emission at 440 nm with excitation at 360 nm and were found to increase the fluorescence intensity with an increase in the amount of PVAm. The blood compatibility studies revealed no significant hemolysis for N-doped C-dots that were prepared at different ratios of CA:PVAm for up to 500 μg/mL concentration with the hemolysis ratio of 1.96% and the minimum blood clotting index of 88.9%. N-doped C-dots were found to be more effective against Gram-positive bacteria than Gram-negative bacteria, with the highest potency on Bacillus subtilis (B. subtilis). The increase in the weight ratio of PVAm in feed during C-dots preparation from 1 to 3 leads to a decrease of the minimum bactericidal concentration (MBC) value from 6.25 to 0.75 mg/mL for B. subtilis. Antibiofilm ability of N-doped C-dots prepared by 1:3 ratio of CA:PVAm was found to reduce %biofilm inhibition and eradication- by more than half, at 0.78 mg/mL for E. coli and B. subtilis generated biofilms and almost destroyed at 25 mg/mL concentrations.

Cellulose acetate-polyvinyl alcohol blend hemodialysis membranes integrated with dialysis performance and high biocompatibility

Hemodialysis considered as therapy of end-stage renal disease (ESRD) for the separation of protein and uremic toxins based on their molecular weights using semi-permeable membranes. Cellulose Acetate (CA) hemodialysis membrane has been widely used in the biomedical field particularly for hemodialysis applications. The main issue of CA membrane is less selectivity and hemocompatibility. In this study, to enhance the filtration capability and biocompatibility of CA hemodialysis membrane modified by using Polyvinyl Alcohol (PVA) and Polyethylene Glycol (PEG) as additives. CA-PVA flat sheet membranes were cast by phase inversion method, and separation was done by dead-end filtration cell. The synthesized membranes were described in terms of chemical structure using Fourier Transform Infrared Spectroscopy (FTIR) and morphology by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), pure water flux, solute permeation, and protein retention. Biocompatibility of the membranes was tested by the platelet adherence, hemolysis ratio, thrombus formation, and plasma recalcification time. SEM images exposed that the CA-PVA membrane has a uniform porous structure. 42.484 L/m2 h is the maximum pure water flux obtained. The CA-PVA rejected up to 95% of bovine serum albumin (BSA). A similar membrane separated 93% of urea and 89% of creatinine. Platelet adhesion and hemolysis ratio of casted membranes were less than the pure CA membrane. Increased clotting time and less thrombus formation on the membrane's surface showed that the fabricated membrane is biocompatible. CA-PVA hemodialysis membranes are more efficient than conventional reported hemodialysis membranes. It revealed that CA-PVA is high performing biocompatible hemodialysis membrane.

Chitosan/alginate/hyaluronic acid polyelectrolyte composite sponges crosslinked with genipin for wound dressing application

Wound dressing composed of polyelectrolyte complexes (PECs), based on chitosan/alginate/hyaluronic acid (CS/ALG/HYA) crosslinked by genipin, was prepared by freeze-dried molding. Genipin as excellent natural biological crosslinker was chose for high biocompatibility and improving mechanical properties of materials. The CS/ALG/HYA sponges (CAHSs) were characterized by FTIR, XRD, DSC and SEM. Porosity, swelling behavior and mechanical properties and in vitro degradation of CAHSs were investigated. The cytotoxicity assay was carried out on HUVEC cells in vitro and the result proves the good biocompatibility of CAHSs. Hemolysis tests indicated that the prepared CAHSs were non-hemolytic material (hemolysis ratio < 5%, no cytotoxicity). PT and aPPT coagulation tests demonstrated that CAHS2 and CAHS3 could both activate the extrinsic and intrinsic coagulation pathway and thus accelerated blood coagulation. Further, in a rat full-thickness wounds model, the CAHS2 sponge significantly facilitates wound closure compared to other groups. CAHSs exhibited adjustable physical, mechanical and biological properties. Thus, the chitosan-based polyelectrolyte composite sponges exhibit great potential as promising wound dressings.

Corrosion Behavior and Biocompatibility of Diamond-like Carbon-Coated Zinc: An In Vitro Study.

Owing to the desirable degradation rate and good biocompatibility, zinc (Zn) and Zn alloys are promising biodegradable implant metals in orthopedic and cardiovascular applications. Surface modification, such as deposition of coatings, is frequently implemented to further enhance their biological properties. In this study, diamond-like carbon (DLC) films are deposited on Zn by magnetron sputtering. The DLC films do not change the surface morphology of Zn but alter the hydrophobic properties with a contact angle of approximately 90°. Electrochemical and in vitro immersion tests reveal that the corrosion resistances of the DLC-coated Zn decrease unexpectedly, which is possibly due to galvanic corrosion between the DLC film and Zn substrate. Furthermore, the uncoated and coated Zn samples show hemolysis ratios less than 1%. The cells cultured in the Zn extract exhibit higher viability than those cultured in the extract of the DLC-coated Zn, suggesting that the DLC films decrease the cytocompatibility of Zn. The lower corrosion resistance has little influence on the hemolysis ratio, suggesting that hemolysis is not an obstacle for the design of Zn-based biomaterials. Our results show that the traditional concept of protection with DLC films may not be applicable universally and decreased corrosion resistance and cytocompatibility are actually observed in DLC-coated Zn.

Synthesis, Characterization, Molecular Docking, In Vitro Biological Evaluation and In Vitro Cytotoxicity Study of Novel Thiazolidine-4-One Derivatives as Anti-Breast Cancer Agents

Thiazolidine-4-one is a promising class of heterocyclic compounds with interesting pharmacological and biological activities, such as anticancer and antibacterial. Therefore, many researchers have synthesized thiazolidine-4-ones and evaluated their biological potential for developing new drugs. In this study, two novel thiazolidine-4-one derivatives (T1 and T2) were synthesized and evaluated for their antibacterial activity toward Staphylococcus aureus, Escherichia coli, and Proteus mirabilis. Also, the cytotoxic activities of compounds T1 and T2 were estimated against MCF-7 (HER2+, ER+, and ER+) and MDAMB- 231 (triple-negative) human breast cancer cell lines. The chemical structures of the compounds T1 and T2 were proven using spectral techniques (FT-IR, 1HNMR, and 13CNMR) and CHN elemental analysis. The synthesis of thiazolidine-4-one compounds was performed in two steps. The first step consisted of the formation of Schiff bases S1 and S2. In the second step, the synthesized Schiff bases were reacted with thioglycolic acid to prepare thiazolidine-4-one compounds. Hemolysis assay, molecular docking, cytotoxicity activity (MTT assay), and antibacterial activity (disc diffusion assay) were studied. The hemolysis study demonstrated that the hemolytic ratio of compounds T1 and T2 at (1, 2, and 3) mg/ml was less than 4%. MTT assay showed that 100 μg/ml of compounds T1 and T2 diminish the MCF-7 cell growth up to 80.05 ± 1.72 and 69.85 ± 3.26 respectively after 72hr., while the same concentration of compounds T1 and T2 reduces the MDA-MB-231 cell growth up 70.28 ± 2.31 and 57.15 ± 1.49, respectively. The inhibition zones of T1 and T2 were 12 mm at 50 mg/ml and 10 mm at 5 mg/ml in E. coli bacteria. Furthermore, a docking study was carried out to investigate the affinity and binding mode of compounds T1 and T2 towards the ERα, VEGF, and HER2 protein receptors in breast cancer cells. Data obtained from the docking study were exactly identical to that obtained from in vitro cytotoxicity assay. The results proved that T1 is an optimal anticancer agent toward breast cancer cells and the hemolysis study indicates the use of safety inside the body for compound T1. Synthesized compound T1 was most effective against MCF-7 cells compared to MDA-MB-231 cells and more effective than the reference drug tamoxifen in breast cell lines. The high cytotoxicity of T1 on the growth of MCF-7 cells because T1 binds with a high degree of affinity to the estrogen and HER2 receptors, which in turn inhibits cell proliferation and induces apoptosis.

Synthesis, Structure Characterization, and Antioxidant and Antibacterial Activity Study of Iso-orientin-Zinc Complex.

Flavonoid-metal complexes possess more effective functional properties than flavonoids. However, the research of iso-orientin (Iso)-metal complex has rarely been reported. In this study, Iso-zinc complex (Iso-Zn, [Zn3(C21H14O11)2]·4H2O) had been synthesized and characterized. From the UV-vis spectra and IR spectra, the 4-carbonyl group in the C-ring of Iso was involved in the metal chelation besides A-ring and B-ring hydroxyl group. Thermal gravimetric analysis and the water contact angle test showed that Iso-Zn had higher thermal stability and better hydrophilicity than Iso, respectively. The radical scavenger and antibacterial potencies of Iso-Zn were significantly stronger than those of Iso. Furthermore, Iso-Zn showed lower erythrocytes hemolysis ratio and cytotoxicity. The present study demonstrated that Iso-Zn exhibited better water solubility, antioxidative and antibacterial activities, and lower cytotoxicity and provided a theoretical basis for expanding the utilization scope of Iso through enhancing its hydrophilicity.

Mechanical alloying and characterization of chlorine doped hydroxyapatite nanopowders

Chlorine-doped Hydroxyapatite (ClHA)(Ca10(PO4)6(OH)2-xClx) nanopowders were successfully synthesized using high planetary ball mill. Milling was carried from 1 to 8 h in order to study the effect of milling time on the doped powders. Additionally, a study on the effect of chlorine addition to HA was also done. XRD results confirmed that all the milled powders consisted apatite as main phase. A significant increase in the unit cell parameters of ClHA nanopowders was observed in contrast to pure HA. However, in doped powders the size decreased with an increase in milling time with a minimal change in the lattice parameters. Microscopic observations also revealed an overall increase in the particle size due to Cl− addition. FTIR results confirmed the incorporation of Cl ions into HA lattice. Hemocompatibility of the synthesized powders (pure HA and ClHA8) was investigated using bovine blood. It was seen that hemolysis ratios for both the samples were below 2%, indicating that the synthesized powders of HA and ClHA are hemocompatible and can be used in various biomedical applications.

P0138 / #1480: COMPARISON OF HEMOLYSIS MARKERS AFTER RBC INFUSION IN SYRINGE INFUSION PUMPS

Aims & Objectives: Syringe infusion pumps (SIP) are used to blood transfusion in some healthcare settings aiming to achieve more accurate infusions in low infusion rates as required by critically ill newborns and infants. Despite the benefits, studies have shown that SIPs can cause red cell damage, increasing the rate of hemolysis of the RBC. The objective of this study was to evaluate hemolysis markers of RBC transfused in three different brands of SIP. Methods: Lab-based experimental study with 16 aliquots of A positive RBC units from different donors. Hemolysis markers (free hemoglobin (g/dL), hemolysis ratio (%) and potassium (mmol/L)) were measured before (control) and after (SIP) RBC infusion. Three different SIP brands (SIPA, SIPB and SIPC) were compared and biomarkers were analyzed in triplicates. Results: Free hemoglobin levels (p=0.114) and hemolysis ratio (p=0.076) increased in all infusions, but without statistical significance; difference according to brands. Potassium levels increased significantly after infusion, and the SIPA caused a threefold increase when compared to SIPB and SIPC (p=0.003). Conclusions: The studied SIPs used to RBC transfusion caused significant alterations on RBC potassium levels and the performance of the devices were different between brands

Multifunctional hybrid nanoplatform based on Fe3O4@Ag NPs for nitric oxide delivery: development, characterization, therapeutic efficacy, and hemocompatibility

The combination of Fe3O4@Ag superparamagnetic hybrid nanoparticles and nitric oxide (NO) represents an innovative strategy for a localized NO delivery with a simultaneous antibacterial and antitumoral actions. Here, we report the design of Fe3O4@Ag hybrid nanoparticles, coated with a modified and nitrosated chitosan polymer, able to release NO in a biological medium. After their synthesis, physicochemical characterization confirmed the obtention of small NO-functionalized superparamagnetic Fe3O4@Ag NPs. Antibacterial assays demonstrated enhanced effects compared to control. Bacteriostatic effect against Gram-positive strains and bactericidal effect against E. coli were demonstrated. Moreover, NO-functionalized Fe3O4@Ag NPs demonstrated improved ability to reduce cancer cells viability and less cytotoxicity against non-tumoral cells compared to Fe3O4@Ag NPs. These effects were associated to the ability of these NPs act simultaneous as cytotoxic (necrosis inductors) and cytostatic compounds inducing S-phase cell cycle arrest. NPs also demonstrated low hemolysis ratio (<10%) at ideal work range, evidencing their potential for biomedical applications.Targeted and hemocompatible nitric oxide-releasing multi-functional hybrid nanoparticles for antitumor and antimicrobial applications.

Catechol functionalized chitosan/active peptide microsphere hydrogel for skin wound healing

Chitosan-based thermosensitive hydrogels have been widely used in drug delivery and tissue engineering, but their poor bioactivity has limited their further applications. Integral active oyster peptide microspheres (OPM) with an average particle diameter of 3.9 μm were prepared with high encapsulation efficiency (72.8%) and loading capacity (11.9%), exhibiting desirable sustained release effects. Using catechol functionalized chitosan (CS-C) as the polymeric matrix, OPM as the filler, and β-sodium glycerophosphate (β-GP) as a thermal sensitizer, the thermosensitive hydrogel CS-C/OPM/β-GP was prepared. Besides, the application of the hydrogel on wound healing was studied, and its biosafety was evaluated. The results of cell migration in vitro showed that the cell migration rate of CS-C/OPM/β-GP reached 97.47 ± 5.41% within 48 h, indicating that the hydrogel accelerated the migration of L929 cells. As demonstrated in the mouse skin wound experiment, CS-C/OPM/β-GP hydrogel not only inhibited the aggregation of diversified inflammatory cells and accelerated the generation of collagen fibers and new blood vessels of the wound, but also enhanced the synthesis of total protein (TP) in granulation tissue, and up-regulated the expression of Ki-67 and VEGF in the injury, thereby achieving fast wound healing. Safety evaluation results showed that CS-C/OPM/β-GP hydrogel was not cytotoxic to L929 cells, and the hemolysis ratio was less than 5% within 1 mg/mL. In conclusion, CS-C/OPM/β-GP hydrogel is expected as a promising medical dressing for wound healing.

Formation mechanism and hemocompatibility of the superhydrophobic surface on biomedical Ti–6Al–4V alloy

The superhydrophobic surface was prepared on biomedical Ti–6Al–4V alloy by hydrothermal treatment coupled with subsequent hydrophobic treatment. The surface morphologies, surface roughness, phase and elemental compositions, water contact angle and hemocompatibility of the superhydrophobic samples were investigated. The results show that the hydrothermally treated sample is mainly composed of Na2Ti6O13 phase with some –OH groups. The surface morphologies of the hydrothermally treated samples change from feather-like structure to grass-like structure, and the surface roughness gradually increases with increasing the concentrations of NaOH solution. After hydrophobic treatment, the surface roughness of samples slightly decreases, and the water contact angles increase first, reaching the maximum value of 159.24° ± 1.89° at 3.75 mol/L, and then decrease with increasing the NaOH concentrations. The –C8H4F13 low surface energy fluorides are grafted onto the surface of hydrothermally treated sample by a self-assembly dehydration reaction, resulting in the formation of the superhydrophobic surface. The superhydrophobic surface effectively decreases the hemolysis ratio and platelets adhesion, and prolongs the dynamic coagulation time, indicating that it greatly improves the hemocompatibility of the biomedical Ti–6Al–4V alloy.

Heparin immobilized graphene oxide in polyetherimide membranes for hemodialysis with enhanced hemocompatibility and removal of uremic toxins

Intermittent hemodialysis is a life-saving renal replacement therapy that removes excess water and uremic salts from patients who suffer from loss of kidney function. Hemocompatible polyetherimide membranes were fabricated by the incorporation of functionalized graphene oxide (f-GO). The f-GO was prepared by immobilizing heparin via the polydopamine anchor onto the nanosheets. The role of the f- GO in altering membrane morphology, surface roughness, wettability, porosity, and surface chemistry were evaluated in detail. The addition of f-GO suppressed the protein adsorption from platelet-poor plasma (>90%) lowered the adhesion (103 times)/activation of platelets, improved the blood clotting time (aPTT/TCT - ~235 s/58.5 s), decreased the thrombin generation and did not activate either complement pathways. Low aggregation of erythrocytes and <2% hemolysis ratio was another indication of improved membrane hemocompatibility. The cell proliferation of Chang liver cells on the f-GO incorporated membranes is an indication of low cytotoxicity of the prepared membranes. The modified hollow fiber membranes displayed exceptional capabilities compared to its pristine counterpart, evidenced by ~ four times higher ultrafiltration coefficient, outstanding removal of uremic toxins after 4 h (Urea- 77 ± 2.5%, creatinine- 68 ± 2% and Lysozyme 44 ± 2%) and ~95% retention of essential protein (albumin). No leaching of the f-GO could be observed from the membrane, and the prepared membranes were robust as they exhibited a sufficiently high solute removal (urea, creatinine, and phosphate) in the ex-vivo run using spiked goat blood. These preliminary investigations point to the fact that f-GO is a suitable modifier, and these membranes can be further explored for hemodialysis application.

In vitro biological activity of Zn substituted hydroxyapatite/ polyvinyl alcohol composite for orthopaedic applications

Zinc substituted hydroxyapatite (Zn-HAP) Ca5-xZnx(PO4)3OH (x = 0, 0.05, 0.2 and 1.0) was synthesized by hydrothermal method. Different weight ratio (30:70, 50:50 and 70:30) of polymer composite (parent HAP and Zn-HAP/PVA (poly vinyl alcohol)) were prepared by solvent casting method. The developed parent and Zn-HAP/PVA composites were characterized by XRD, FTIR and SEM-EDAX to examine the phase composition, functional groups and morphology. Porosity, swelling percentage, mechanical strength, antibacterial activity, hemocompatibility, bioactivity and cytotoxicity were studied. Increase in porosity (88.90 ± 1.20–97.25 ± 1.12 %) and mechanical strength (44.45–98.94 MPa) were observed with the increase in the wt% of Zn-HAP in the PVA network. Furthermore, In-vitro hemocompatibility assay showed that all composites were hemocompatible with less than 2% hemolytic ratio. In-vitro biomineralization of the optimized composite (Zn-HAP/PVA with 30:70 (w/w)) showed a new apatite formation on the surface of the composite after soaking in simulated body fluid (SBF) for 28 days. Further, the cytotoxicity of the optimized composite was evaluated against human osteoblast cells (HOS). Zn-HAP/PVA with 30:70 was found to have higher cell viability (p < 0.01) compared to the pure (HAP/PVA) composite.

Tentative identification of key factors determining the hemostatic efficiency of diatom frustule.

It is increasingly essential to develop excellent materials for rapid hemorrhage control. Our previous study showed that centric diatoms such as frustules were superior to QuikClot® in hemostasis, however, related studies in pennate diatoms are still scarce. The morphological and physicochemical properties of pennate diatoms are quite different from those of centric diatoms, meaning that significant differences may also be observed from their hemostatic effects. Thus, the hemostasis effects of four pennate diatom frustules (Cocconeiopsis orthoneoides, Navicula avium, Navicula sp., and Pleurosigma indicum) were investigated in this study. Herein, all diatom frustules demonstrated outstanding hemostasis performance. For example, the in vitro coagulation time of C. orthoneoides (100.33 ± 9.5 s) was 32.4% lower than that of QuikClot®. Meanwhile, the hemostatic times of C. orthoneoides in the rat tail amputation and femoral artery models were 82 s and 180 s, respectively, only around one-half and one-third of the QuikClot® values. Moreover, the blood loss amounts of C. orthoneoides in the rat tail amputation and femoral artery model were 73.4% and 61% less than that of QuikClot®. Besides that, diatom frustules also exhibited favorable biocompatibility (hemolysis ratio <5%, MEFs cell viabilities >80%, and no inflammation). To find out the key factors underlying the hemostatic effect of frustules, Pearson correlation analysis was further performed in this study. The results demonstrated that the coagulation reaction time (R) was negatively correlated with the specific surface area and liquid absorbability but positively with the diatom pore diameter. The angle α, indicating the clot formation rate, was negative to the diatom size and pore diameter. Additionally, MA also showed a negative correlation with the BET value. This study can enrich our knowledge about the application potential of diatoms in the field of bleeding control and is helpful in deepening our understanding about the hemostatic mechanism of frustules.

Synthesis and characterization of iron oxide-hydroxyapatite-chitosan composite coating and its biological assessment for biomedical applications

Hydroxyapatite coatings are widely employed to enhance the osseointegration ability and bioactivity of biodegradable magnesium alloys as biodegradable implants. To further enhance the efficiency of hydroxyapatite-coated magnesium alloys, iron oxide particles were used along with hydroxyapatite to produce the antimicrobial and bioactive coating via electrophoretic deposition. The coatings were integrated in a matrix of chitosan. The experiments were carried out with different iron oxide particle concentrations i.e., 1, 3 and 5 (wt. %)), respectively. The antimicrobial property was investigated in Escherichia coli and Staphylococcus aureus strains, which confirmed that the micro-organisms development was suppressed by the significant rise of iron oxide particles. Evaluation of bioactivity behavior was carried out in phosphate buffer saline for 7 days, and the composite coatings were found to enhance the apatite mineralization, as affirmed by SEM-EDX analysis. The assessment of hemocompatibility showed that the hemolysis ratio was less than 5 %, which confirms that the coatings were blood compatible in nature. The outcomes showed that hydroxyapatite-iron oxide-chitosan composite coating may be extensively utilized as an appropriate material for biomedical implant applications.

Electrophoretic deposition of Fe3O4 nanoparticles incorporated hydroxyapatite-bioglass-chitosan nanocomposite coating on AZ91 Mg alloy

The present work concentrates on the electrophoretic deposition (EPD) of hydroxyapatite, bioglass and iron oxide nanoparticles nanocomposite coating into chitosan matrix on AZ91 Mg alloy. The iron oxide nanoparticles formed by the co-precipitation method and varied at 1, 3 and 5 (wt %) concentration in the bioactive coatings. Scanning electron microscopy graphs exhibited that the nanocomposite coatings had a porous spherical structure. The hydroxyapatie-bioglass-1% iron oxide coating demonstrated the highest corrosion resistance among all the samples. The hemocompatibility tests indicated a hemolysis ratio < 5%, and no detrimental effects on the erythrocytes. The findings revealed that hydroxyapatite-bioglass- iron oxide-chitosan coating could be considered as potential candidate for degradable implant applications.