Biological evaluation and osteogenic potential of polyhydroxybutyrate-keratin/Al2O3 electrospun nanocomposite scaffold: A novel bone regeneration construct.

In this study, the effect of alumina nanowire on the physical and biological properties of polyhydroxybutyrate-keratin (PHB-K) electrospun scaffold was investigated. First, PHB-K/alumina nanowire nanocomposite scaffolds were made with an optimal concentration of 3 wt% alumina nanowire by using the electrospinning method. The samples were examined in terms of morphology, porosity, tensile strength, contact angle, biodegradability, bioactivity, cell viability, ALP activity, mineralization ability, and gene expression. The nanocomposite scaffold provided a porosity of >80 % and a tensile strength of about 6.72 MPa, which were noticeable for an electrospun scaffold. AFM images showed an increase in surface roughness with the presence of alumina nanowires. This led to an improvement in the degradation rate and bioactivity of PHB-K/alumina nanowire scaffolds. The viability of mesenchymal cells, alkaline phosphatase secretion, and mineralization significantly increased with the presence of alumina nanowire compared to PHB and PHB-K scaffolds. In addition, the expression level of collagen I, osteocalcin, and RUNX2 genes in nanocomposite scaffolds increased significantly compared to other groups. In general, this nanocomposite scaffold could be a novel and interesting construct for osteogenic induction in bone tissue engineering.

Nanoemulsion carriers of porous γ-alumina modified by polyvinylpyrrolidone and carboxymethyl cellulose for pH-sensitive delivery of 5-fluorouracil.

5-Fluorouracil (5-FU) is a cytotoxic drug with a low half-life. These features can cause some problems such as burst drug release and numerous side effects. In the present study, a pH-sensitive nanocomposite of polyvinylpyrrolidone (PVP)/carboxymethyl cellulose (CMC)/γ-alumina developed by using water in oil in water (W/O/W) double emulsion method. The fabricated emulsion has been employed as the 5-FU carrier to investigate its effects on drug half-life, side effects, drug loading efficiency (DLE), and drug entrapment efficiency (DEE). Analyzing the FTIR and XRD indicated the successful loading of 5-FU into the nanocarrier and affirmed the synthesized nanocomposite's chemical bonding and crystalline features. Furthermore, by using DLS and Zeta potential assessment, size and undersize distribution, as well as the stability of the drug-loaded nanocomposite were determined, which demonstrated the monodisperse and stable nanoparticles. Moreover, the nanocomposites with spherical shapes and homogeneous surfaces were shown in FE-SEM, which indicated good compatibility for the constituents of the nanocomposites. Moreover, by employing BET analysis the porosity has been investigated. Drug release pattern was studied, which indicated a controlled drug release behavior with above 96 h drug retention. Besides, the loading and entrapment efficiencies were obtained 44 % and 86 %, respectively. Furthermore, the curve fitting technique has been employed and the predominant release mechanism has been determined to evaluate the best-fitted kinetic models. MTT assay and flow cytometry assessment has been carried out to investigate the cytotoxic effects of the fabricated drug-loaded nanocomposite on MCF-7 and normal cells. The results showed enhanced cytotoxicity and late apoptosis for the PVP/CMC/γ-alumina/5-FU. Based on the MTT assay outcomes on normal cell lines (L929), which indicated above 90 % cell viability, the biocompatibility and biosafety of the synthesized nanocarrier have been confirmed. Moreover, due to the porosity of the PVP/CMC/γ-alumina, this nanocarrier can exploit from high specific surface area and be more sensitive to environmental conditions such as pH. These outcomes propose that the novel pH-sensitive PVP/CMC/γ-alumina nanocomposite can be a potential candidate for drug delivery applications, especially for cancer therapy.

Aluminum Oxide Nanoparticles Impair Working Memory and Neuronal Activity through the GSK3ß/BDNF Signaling Pathway of Prefrontal Cortex in Rats.

Studies demonstrated that alumina nanoparticles (alumina NPs) impair spatial cognition and hippocampus-dependent synaptic plasticity. Although alumina NPs accumulate in the prefrontal cortex (PFC), their effects on PFC-mediated neuronal and cognitive function have been not yet documented. Here, alumina NPs (10 or 20 µg/kg of body weight) were bilaterally injected into the medial PFC (mPFC) of adult rats, and the levels of glycogen synthase kinase 3ß (GSK3ß) and the brain-derived neurotrophic factor (BDNF) were detected. The PFC-dependent working memory task with one-minute or three-minute delay time was conducted. Meanwhile, the neuronal correlates of working memory performance were recorded. The specific expression of neuronal BDNF was assessed by colabeled BDNF expression with the neuronal nuclear antigen (NeuN). Whole-cell patch-clamp recordings were employed to detect neuronal excitability. Intra-mPFC alumina NP infusions significantly enhanced the expression of GSK3ß but reduced the phosphorylation of GSK3ß (pGSK3ß) and BDNF levels more severely at a dose of 20 µg/kg. Alumina NPs acted in a dose-dependent manner to impair working memory. The neuronal expression of BDNF in the 20 µg/kg group was markedly declined compared with the 10 µg/kg group. During the delay time, the neuronal frequency of pyramidal cells but not interneurons was significantly weakened. Furthermore, both the frequency and amplitude of the excitatory postsynaptic currents (EPSCs) were descended in the mPFC slices. Additionally, the infusion of GSK3ß inhibitor SB216763 or BDNF could effectively attenuate the impairments in neuronal correlate, neuronal activity, and working memory. From the perspective of the identified GSK3ß/BDNF pathway, these findings demonstrated for the first time that alumina NPs exposure can be a risk factor for prefrontal neuronal and cognitive functions.

Antimicrobial materials with improved efficacy dedicated to large craniofacial bone defects after tumor resection.

The research was focused on alternative treatment techniques, separating immediate and long-term reconstruction stages. The work involved development of ceramic materials dedicated to reconstruction of the temporomandibular joint area. They were based on alumina (aluminum oxide) and characterized by varying porosities. A broad spectrum of studies was conducted to test the proposed material and determine its suitability for mandibular reconstruction. They compared the effects of substrate properties of ceramic materials in terms of biocompatibility, microbiology and systemic toxicity in in vivo studies. Finally it was concluded that Alumina LithaLox 350D is best suited for jawbone implants.

Chitosan/Gamma-Alumina/Fe3O4@5-FU Nanostructures as Promising Nanocarriers: Physiochemical Characterization and Toxicity Activity.

Today, cancer treatment is an important issue in the medical world due to the challenges and side effects of ongoing treatment procedures. Current methods can be replaced with targeted nano-drug delivery systems to overcome such side effects. In the present work, an intelligent nano-system consisting of Chitosan (Ch)/Gamma alumina (γAl)/Fe3O4 and 5-Fluorouracil (5-FU) was synthesized and designed for the first time in order to influence the Michigan Cancer Foundation-7 (MCF-7) cell line in the treatment of breast cancer. Physico-chemical characterization of the nanocarriers was carried out using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), dynamic light scattering (DLS), and scanning electron microscopy (SEM). SEM analysis revealed smooth and homogeneous spherical nanoparticles. The high stability of the nanoparticles and their narrow size distribution was confirmed by DLS. The results of the loading study demonstrated that these nano-systems cause controlled, stable, and pH-sensitive release in cancerous environments with an inactive targeting mechanism. Finally, the results of MTT and flow cytometry tests indicated that this nano-system increased the rate of apoptosis induction on cancerous masses and could be an effective alternative to current treatments.

Sesamol protects against aluminum oxide nanoparticles-induced hepatorenal toxicity in rats via modulation of oxidative stress, inflammation, apoptosis, and DNA damage.

Aluminum oxide nanoparticles (Al2 O3 -NPs) are exceedingly used in various industrial and commercial applications, providing growing concerns about their potential adverse impacts on animals and human health. Therefore, the present study was conducted to evaluate the potential protective effect of sesamol (SML) against the induced hepatorenal toxicity of Al2 O3 -NPs. Forty male rats were randomly assigned into four groups and treated orally for 28 consecutive days. Control group received distilled water. SML group received SML (100 mg/kg bw). Al2 O3 -NPs group received Al2 O3 -NPs (100 mg/kg bw). SML + Al2 O3 -NPs group received SML 2 h prior to Al2 O3 -NPs. The results revealed that Al2 O3 -NPs significantly increased serum alanine aminotransferase and aspartate aminotransferase activities and serum urea and creatinine levels. Moreover, Al2 O3 -NPs induced a significant elevation in malondialdehyde level with significant reduction in reduced glutathione content and catalase and superoxide dismutase activities, together with a marked increase of 8-hydroxy-2-desoxyguanosine level in the hepatic and renal tissues. Also, up-regulations of glutathione-S-transferase, tumor necrosis factor-alpha, and caspase-3 mRNA gene expressions were recorded in the liver and kidneys. Additionally, Al2 O3 -NPs induced multifocal areas of necrosis in hepatic parenchyma with glomerular mesangial cell proliferation and glomerular sclerosis in kidney tissues. Conversely, concomitant treatment with sesamol mitigated Al2 O3 -induced hepatorenal toxicity evidenced by improvement of liver and kidney functions that correlated with regulation of oxidant/antioxidant status, inflammatory, and apoptotic biomarkers and reduction of DNA and tissues damages. In conclusion, sesamol could exert a promising protective role against hepatorenal toxicity of Al2 O3 -NPs, possibly via its antioxidant, anti-inflammatory and anti-apoptotic properties.

New Carbon-Mineral Sorbent Based on Aluminum Oxide, Polydimethylsiloxane, and Single-Wall Carbon Nanotubes: Assessment of the Effect on Erythrocytes In Vitro.

A comparative study of the effect of a sorbent with nanotubes (Al2O3@ WCNT-PDMS) and a carbon-mineral sorbent (Al2O3@C) on the parameters of human erythrocytes was carried out. Using scanning flow cytometry, the morphological and functional parameters of venous blood erythrocytes as well as drainage blood after its perfusion through columns with sorbents were determined. The compared samples Al2O3@SWCNT-PDMS and Al2O3@C are similar by their effect on the morphological and functional parameters of erythrocytes. The maximum membrane extensibility increased to a greatest extent after contact with Al2O3@C, the amount of hemoglobin in erythrocytes decreased to the greatest extent after perfusion through a column with Al2O3@SWCNT-PDMS sorbent. The scanning flow cytometry is promising for assessing the effect on erythrocytes of new sorption materials intended for blood detoxification. Changes in the parameters of erythrocytes of blood collected in a sterile drainage system for subsequent reinfusion were revealed.

Hepatic enzymes and immunoinflammatory response to Bio-C Temp bioceramic intracanal medication implanted into the subcutaneous tissue of rats.

Our purpose was to evaluate the biocompatibility and hepatotoxicity of a new bioceramic intracanal medicament, Bio-C Temp (BIO). The biological properties of BIO were compared with calcium hydroxide-based intracanal medicament (Calen; CAL), used as gold pattern. Polyethylene tubes filled with BIO or CAL, and empty tubes (control group, CG) were implanted into subcutaneous tissue of rats. After 7, 15, 30 and 60 days, the samples were embedded in paraffin for morphological, quantitative and immunohistochemistry analyses. At 7 and 60 days, blood samples were collected for analysis of serum glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) levels. The data were submitted to two-way ANOVA and Tukey's test (p ≤ 0.05). No significant difference was detected in serum GOT and GPT levels among BIO, CAL and CG specimens. In all periods, BIO specimens exhibited lower number of inflammatory cells and immunoexpression of IL-6, a pro-inflammatory cytokine, than CAL specimens. The reduction of these parameters was accompanied by significant increase in the collagen content and in the immunoexpression of IL-10, a cytokine involved in the tissue repair, over time. Our findings indicate that Bio-C Temp is biocompatible and had no hepatotoxicity effect.

Rationale, design, demographics and baseline characteristics of the randomized, controlled, Phase 2b SAPPHIRE study of verinurad plus allopurinol in patients with chronic kidney disease and hyperuricaemia.

BACKGROUND: Verinurad is a human uric acid (UA) transporter (URAT1) inhibitor known to decrease serum UA (sUA) levels and that may reduce albuminuria. In a Phase 2a study (NCT03118739), treatment with verinurad + febuxostat lowered urine albumin-to-creatinine ratio (UACR) at 12 weeks by 39% (90% confidence interval 4-62%) among patients with Type 2 diabetes mellitus, hyperuricaemia and albuminuria. The Phase 2b, randomized, placebo-controlled Study of verinurAd and alloPurinol in Patients with cHronic kIdney disease and hyperuRicaEmia (SAPPHIRE; NCT03990363) will examine the effect of verinurad + allopurinol on albuminuria and estimated glomerular filtration rate (eGFR) slope among patients with chronic kidney disease (CKD) and hyperuricaemia. METHODS: Adults (≥18 years of age) with CKD, eGFR ≥25 mL/min/1.73 m2, UACR 30-5000 mg/g and sUA ≥6.0 mg/dL will be enrolled. Approximately 725 patients will be randomized 1:1:1:1:1 to 12, 7.5 or 3 mg verinurad + allopurinol, allopurinol or placebo. An 8-week dose-titration period will precede a 12-month treatment period; verinurad dose will be increased to 24 mg at Month 9 in a subset of patients in the 3 mg verinurad + allopurinol arm. The primary efficacy endpoint the is change from baseline in UACR at 6 months. Secondary efficacy endpoints include changes in UACR, eGFR and sUA from baseline at 6 and 12 months. CONCLUSIONS: This study will assess the combined clinical effect of verinurad + allopurinol on kidney function in patients with CKD, hyperuricaemia and albuminuria, and whether this combination confers renoprotection beyond standard-of-care.

Enhancement of the anticoagulant capacity of polyvinyl chloride tubing for cardiopulmonary bypass circuit using aluminum oxide nanoscale coating applied through atomic layer deposition.

For cardiopulmonary bypass, the polyvinyl chloride (PVC) circuit which can initiate the activation of platelets and the coagulation cascade after blood cell contacting is the possible detrimental effect. Surface coating of the PVC tubing system can be an effective approach to enhance circuit's hemocompatibility. In this study, aluminum oxide (Al2 O3 ) thin films were deposited through thermal atomic layer deposition (T-ALD) or plasma-enhanced ALD (PE-ALD) on PVC samples, and the anticoagulation of the Al2 O3 -coated PVC samples was demonstrated. The results revealed that Al2 O3 deposition through ALD increased surface roughness, whereas T-ALD had a relative hydrophilicity compared with blank PVC and PE-ALD. Whole blood immersion tests showed that blood clots formed on blank PVC and that a large amount of red blood cells was found on PE-ALD substrates, whereas less blood cells were noted in T-ALD samples. Both T-ALD and PE-ALD Al2 O3 films did not cause activation of blood cells, as evidenced in CD3+ /CD4+ /CD8+ , CD61+ /CD62P+ , and CD45+ /CD42b+ populations. Analysis of serum coagulation factors showed that a lower amount of prothrombin was absorbed on T-ALD Al2 O3 samples than that on blank PVC. For albumin and fibrinogen immersion tests, immunostaining and scanning electron microscopy further revealed that a thin albumin layer was absorbed on T-ALD Al2 O3 substrates but not on PVC samples. This study revealed that deposition of Al2 O3 films by T-ALD can improve anticoagulation of the PVC tubing system.

Plasmonic nanorod array for effective photothermal therapy in hyperthermia.

Optical properties of anisotropic gold nanorod arrays inside anodic aluminium oxide substrates enhance the longitudinal absorption intensities and the hyperthermia cancer cell killing at 42.1 °C under photothermal laser exposures at 671 nm.

Pseudoboehmite as a drug delivery system for acyclovir.

Herpes simplex virus is among the most prevalent sexually transmitted infections. Acyclovir is a potent, selective inhibitor of herpes viruses and it is indicated for the treatment and management of recurrent cold sores on the lips and face, genital herpes, among other diseases. The problem of the oral bioavailability of acyclovir is limited because of the low permeability across the gastrointestinal membrane. The use of nanoparticles of pseudoboehmite as a drug delivery system in vitro assays is a promising approach to further the permeability of acyclovir release. Here we report the synthesis of high purity pseudoboehmite from aluminium nitrate and ammonium hydroxide containing nanoparticles, using the sol-gel method, as a drug delivery system to improve the systemic bioavailability of acyclovir. The presence of pseudoboehmite nanoparticles were verified by infrared spectroscopy, transmission electron microscopy, and X-ray diffraction techniques. In vivo tests were performed with Wistar rats to compare the release of acyclovir, with and without the addition of pseudoboehmite. The administration of acyclovir with the addition of pseudoboehmite increased the drug content by 4.6 times in the plasma of Wistar rats after 4 h administration. We determined that the toxicity of pseudoboehmite is low up to 10 mg/mL, in gel and the dried pseudoboehmite nanoparticles.

Inflammatory responses to metal oxide ceramic nanopowders.

Ceramic orthopaedic implants are increasingly popular due to the need for robust total joint replacement implants that have a high success rate long-term and do not induce biological responses in patients. This study was designed to investigate the biological effects of ceramic nanopowders containing aluminium oxide or zirconium oxide to activate the human macrophage THP-1 cell line. In vitro investigation of pro-inflammatory gene expression and chemokine secretion was performed studied using RT-qPCR and ELISA, respectively. TLR4 inhibition, using a small-molecule inhibitor, was used to determine whether ceramic-mediated inflammation occurs in a similar manner to that of metals such as cobalt. THP-1 macrophages were primed with ceramics or LPS and then treated with ATP or ceramics, respectively, to determine whether these nanopowders are involved in the priming or activation of the NLRP3 inflammasome through IL-1ß secretion. Cells treated with ceramics significantly increased pro-inflammatory gene expression and protein secretion which was attenuated through TLR4 blockade. Addition of ATP to cells following ceramic treatment significantly increased IL-1ß secretion. Therefore, we identify the ability of ceramic metal oxides to cause a pro-inflammatory phenotype in THP-1 macrophages and propose the mechanism by which this occurs is primarily via the TLR4 pathway which contributes to inflammasome signalling.

The biological synthesis of gold/perlite nanocomposite using Urtica dioica extract and its chitosan-capped derivative for healing wounds infected with methicillin-resistant Staphylococcus aureus.

The preparation of ointments from natural compounds is essential for accelerating infected wounds. This study investigated the effects of topical uses of gold nanoparticles (Au)/perlite (Au/Perl) nanocomposites (NCs) by the help of Urtica dioica extract and its chitosan-capped derivative (Chit) on methicillin-resistant Staphylococcus aureus (MRSA)-infected wound healing in a mouse model. Furthermore, Au/Perl/Chit nanocomposite was prepared using protonated chitosan solution. The physicochemical properties of the as-synthesized nanocomposites were also investigated. The effects of Au/Perl/Chit NC were assessed by antibacterial, histopathological parameters as well as molecular evaluations. Then, they were compared with synthetic agent of mupirocin. The results revealed that Au/Perl NC was mesoporous and spherical in a range of 13-15 nm. Topical administration of Au/Perl/Chit ointment accelerated wound healing by reducing bacteria colonization and wound rate enhancing collagen biosynthesis and re-epithelialization, the expressions of IL-10, PI3K, AKT, bFGF, and COL1A genes, which is in agreement with the obtained results for mupirocin. In conclusion, the results strongly demonstrated that administration of ointments prepared from Au/Perl and Au/Perl/Chit nanocomposites stimulates MRSA-infected wound healing by decreasing the length of healing time and regulating PI3K/AKT/bFGF signaling pathway and is a promising candidate in stimulating MRSA-infected wound regeneration.

Synthesis and characterization of chitosan/polyvinylpyrrolidone coated nanoporous γ-Alumina as a pH-sensitive carrier for controlled release of quercetin.

pH-sensitive drug delivery systems based on amphiphilic copolymers constitute a promising strategy to overcome some challenges to cancer treatment. In the present study, quercetin-loaded chitosan/polyvinylpyrrolidone/γ-Alumina nanocomposite was fabricated through a double oil in water emulsification method for the first time. γ-Alumina was incorporated to improve the drug loading efficiency and release behavior of polyvinylpyrrolidone and chitosan copolymeric hydrogel. γ-Alumina nanoparticles were obtained by the sol-gel method with a nanoporous structure, high surface area, and hydroxyl-rich surface. Quercetin, a natural anticancer agent, was loaded into the nanocomposite as a drug model. XRD and FTIR analyses confirmed the crystalline properties and chemical bonding of the prepared nanocomposite. The size of drug-loaded nanocomposites was 141 nm with monodisperse particle distribution, having a spherical shape approved by DLS analysis and FE-SEM, respectively. Incorporating γ-Alumina nanoparticles improved the encapsulation efficiency up to 95%. Besides, swelling study and the quercetin release profile demonstrated that γ-Alumina ameliorated pH sensitivity of nanocomposite and a targeted controlled release was obtained. Various release kinetic models were applied to the experimental release data to study the mechanism of drug release. Through MTT assay and flow cytometry, the quercetin-loaded nanocomposite showed significant cytotoxicity on MCF-7 breast cancer cells. Also, the enhanced apoptotic cell death confirmed the anticancer activity of γ-Alumina. These results suggest that the chitosan/polyvinylpyrrolidone/γ-Alumina nanocomposite is a novel pH-sensitive drug delivery system for anticancer applications.

Effect of a New Lithium Preparation on the Behavior of CBA/CaLac Mice in an Experimental Conflict Model.

The use of lithium drugs in clinical practice requires constant monitoring of lithium plasma concentration, because toxicity is sometimes observed at therapeutic concentrations of lithium. This is often associated with fluctuations of plasma concentration of lithium ions after intake of individual doses. Therefore, the use of a porous carrier providing a stable blood level of the drug is extremely promising and important for clinical practice. We studied activity of a new lithium drug (lithium complex) consisting of aluminum-silicon base and lithium citrate immobilized on its surface. Lithium carbonate served as the reference drug. It was shown that lithium carbonate and lithium complex exhibited no anxiolytic activity in the conflict model, but produced an antidepressant effect and improved exploratory behavior of animals.

Multifunctional Coating with Both Thermal Insulation and Antibacterial Properties Applied to Nickel-Titanium Alloy.

BACKGROUND: With excellent shape memory and superelastic properties, shape memory alloy (SMA) is an ideal actuator, and it can form smart structure for different applications in medical field. However, SMA devices cause apparent thermal damage to the surrounding tissues when it works in vivo, making the application of smart structure that is composed of SMA actuator in vivo is greatly limited. METHODS: In this paper, coating (APA) with PLA as the main body to limit the heat conduction, a multifunctional Ag nanoparticles (AgNPs)/polylactic acid (PLA)/Al2O3 was synthesized. The Al2O3 layer was formed by micro-arc oxidation (MAO) and AgNPs were synthesized by silver nitrate and ethylene glycol. Scanning electron microscopy, transmission electron microscope, and Fourier transform infrared spectra were applied to analyze the morphology and characterization of APA coating. The antimicrobial activity, thermal insulation activity, and biocompatibility of APA coating were furtherly explored and verified through animal experiments and immunohistochemistry. RESULTS: With different particle sizes and concentrations of AgNPs, APA multi-functional films were successfully prepared. The Al2O3 layer was closely combined with SMA and formed a porous surface, so the PLA and AgNPs layers can firmly adhere to SMA, thus reducing the release of nickel ions in SMA. AgNPs gave APA coating excellent antibacterial activity and effectively inhibited the growth of Staphylococcus aureus. In addition, coupled with the low thermal conductivity of PLA and Al2O3, AgNPs were tightly anchored on the surface of PLA, which has high infrared reflectivity, making the APA coating obtain good thermal insulation performance. CONCLUSION: We have successfully prepared the APA coating and obtained the optimum amount of AgNPs, which makes it have good thermal insulation performance, good antibacterial activity and good biocompatibility, which provides a new prospect for the application of SMA.

In vitro and in vivo study of naturally derived alginate/hydroxyapatite bio composite scaffolds.

Biogenic bioceramics scaffolds are receiving considerable attention for bone restoration applications. Compared with scaffolds of chemical origin, biogenic scaffolds exhibit greater biocompatibility and enhanced bioactive features. In the present study, porous biogenic hydroxyapatite (bHA) was prepared via a polymeric infiltration route and was subsequently coated with alginate to produce alginate/biogenic hydroxyapatite (Alg/bHA) composites. Alginate was used to enhance the mechanical properties as well as the bioactivity and biodegradability of the HA scaffolds. A coating of 3%w/v alginate applied for 10 min was found to result in the best coating for the HA porous scaffolds. The in vitro study demonstrated that the prepared composites had acceptable bioactivity and biodegradability characteristics. The histological study in femur bone of rats indicated that the 3Alg/HA scaffolds capable of supporting both endochondral and intramembranous bone formation. The defect was fully regenerated and mostly filled with the mature lamellar bone after 6 months, with Ca/P atomic ratio similar to the rat's normal bone. The studied scaffolds provide a promising therapeutic option to enhance local bone healing because they do not damage liver or kidney functions and do not induce carcinogenic or inflammatory effects. Accordingly, 3Alg/HA scaffolds are recommended for the tissue engineering applications.

Synthesis and enhanced antioxidant and membrane-protective activity of curcumin@AlOOH nanoparticles.

The ever increasing demand for nanoantioxidants with minimized toxicity dictates the necessity to develop new biocompatible materials. One promising approach is the immobilization of polyphenols on metal (oxy)hydroxide nanoparticles (NPs) that possess the desired chemical and colloidal stability while also allowing to dispose of the antioxidants more safely and effectively. In this paper we modify sol-gel synthesized γ-AlOOH NPs with curcumin molecules. The prepared colloidal systems are hydrosols, stable in acidic, neutral and slightly basic pH values. UV-vis and FTIR spectroscopies suggest that the mechanism of curcumin binding lies in the H-bonding of its functional groups to hydroxyls of pseudoboemite. Modification of AlOOH nanoparticles shifts its isoelectric point from 9.7 to 9.3 due to the weak acidic centers of the polyphenol. Immobilization of curcumin molecules on pseudoboehmite allows to achieve good solubility of the phenol in water and to reduce the level of its hemolytic activity (indicating good biocompatibility). At the same time, it preserves radical scavenging activity and in some experimental designs even enhances antioxidant and membrane-protective activity (enhancement ≥30%) in vitro on cellular and non-cellular models.

Design of γ-AlOOH, γ-MnOOH, and α-Mn2O3 nanorods as advanced antibacterial active agents.

In the current study, γ-AlOOH, γ-MnOOH, and α-Mn2O3 nanorods (NRs) were easily synthesized and applied as advanced antibacterial materials. γ-AlOOH NRs with 20 nm width, [100] crystal plane, and 200 nm length were fabricated through a surfactant-directed solvothermal method. γ-MnOOH NRs with 20 nm width, [101] crystal direction and 500 nm length were fabricated through a hydrothermal method. The prepared γ-MnOOH NRs were calcinated (for 5 h) at 700 °C to produce α-Mn2O3 NRs with 20 nm average width and increased surface area. The NRs' structures were confirmed through FT-IR, XRD, XPS, FESEM, and FETEM. The antibacterial activity of the NRs was studied against different Gram-negative and Gram-positive bacterial strains and yeast. The three NRs exhibited antibacterial activity against all of the used strains. Biological studies indicated that the NRs' antimicrobial activity increased in the order of γ-MnOOH < γ-AlOOH < α-Mn2O3 NRs. The α-Mn2O3 NRs exhibited the lowest MIC value (39 µg mL-1) against B. subtilis, B. pertussis, and P. aeruginosa. The prepared NRs exhibited a higher antimicrobial potential toward Gram-positive bacteria than Gram-negative bacteria. The higher antimicrobial activity of the α-Mn2O3 NRs is highlighted based on their larger surface area and smaller diameter. Consequently, uniform NR architectures, single crystallinity, small nanoscale diameters, and more highly exposed [110] Mn-polar surfaces outwards are promising structures for α-Mn2O3 antibacterial agents. These NRs adhered firmly to the bacterial cells causing cell wrapping and morphology disruption, and microbial death. The designed NRs provide a great platform for microbial growth inhibition.