Freeze-drying Method Research Articles

Biperiden Hydrochloride/β -Cyclodextrins supramolecular system and its cytotoxicity against lung adenocarcinoma cells

Understanding the supramolecular structures and the host and guest interactions of supramolecular systems is crucial to corroborate the biological findings. In this sense, combining experimental and theoretical approaches has allowed to comprehend the interactions between cyclodextrins (CDs) and guest molecules. Herein, biperiden hydrochloride (BPR) was successfully included into the β -cyclodextrin (β CD) using freeze-drying method. The drug solubility increased in presence of β CD and the thermodynamic parameters for the inclusion process determined by isothermal titration calorimetry (ITC). ITC indicated that the β CD supramolecular system formed a 1:1 inclusion complex. The 2D nuclear magnetic resonance (NMR) results for the β CD:BPR suggested an equilibrium between two different supramolecular complexes in solution, since cross peak correlations with to different moieties was observed. The ITC and NMR findings were corroborated by the theoretical calculations. Moreover, the inclusion complexes’ cytotoxicity was tested against lung adenocarcinoma cells, demonstrating that β CD:BPR supramolecular system is promising for further investigation, while free BPR demonstrated to be a non-cytotoxic agent against A549 human cells.

Screening of Cyclodextrins in the Processing of Buserelin Dry Powders for Inhalation Prepared by Spray Freeze-Drying.

In this study, we prepared inhalable buserelin microparticles using the spray freeze-drying (SFD) method for pulmonary drug delivery. Raffinose as a cryoprotectant carrier was combined with two levels of five different cyclodextrins (CDs) and then processed by SFD. Dry powder diameters were evaluated by laser light scattering and morphology was determined by scanning electron microscopy (SEM). Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis were utilized for the determination of crystalline structures. The aerodynamic properties of the spray freeze-dried powders were evaluated by twin stage impinger (TSI) and the stability of prepared samples was assessed under normal and accelerated conditions. The prepared powders were mostly porous spheres and the size of microparticles ranged from 9.08 to 13.53 μm, which are suitable as spray-freeze dried particles. All formulations showed amorphous structure confirmed by DSC and XRD. The aerosolization performance of the formulation containing buserelin, raffinose and 5% beta-cyclodextrin (β-CD), was the highest and its fine particle fraction (FPF) was 69.38%. The more circular and separated structures were observed in higher concentrations of CDs, which were compatible with FPFs. The highest stability was obtained in the formulation containing hydroxypropyl beta-cyclodextrin (HP-β-16. CD) 5%. On the contrary, sulfobutylether beta-cyclodextrin (SBE-β-CD) 5% bearing particles showed the least stability. By adjusting the type and ratio of CDs in the presence of raffinose, the prepared formulations could effectively enhance the aerosolization and stability of buserelin. Therefore, they can be proposed as a suitable career for lung drug delivery.

A facile strategy for constructing lightweight, fire safety and compression resistance poly(vinylalcohol) aerogels with highly-efficient expansible graphene oxide/layered double hydroxides hybrid synergistic flame retardant

Poly(vinyl alcohol) (PVA) aerogels with excellent environmentally friendly properties have been considered to replace undegradable polymer foams. However, due to highly flammable, hydrophilic, and worse compression resistance performance, PVA aerogels have always been excluded from practical. Herein, a fire safety and compression resistance PVA/expansible graphene oxide (EGO)/Layered double hydroxides (LDHs) (PGL) aerogel was prepared via the freeze-drying method and electrostatic adsorption of flame retardant. The ice crystals from aerogels were sublimated and left a mass of tree-like pore tunnel structures. Meantime, the compound of EGO and LDHs rendered PGL aerogels high compressive strength of 6.0917 MPa (at 80% of strains), a high specific modulus of 19.16 m2/s2, and an ultra-low density of 0.059 g/cm3. Especially, the as-prepared PGL aerogels showed heat release reduced by 55.4%, smoke release reduced by 54.3%, and the limiting oxygen index reaching up to 31%. Moreover, LDHs also enhanced the interface with PVA/EGO resulting in hydrophobic performance improvement. The proposed enhancements mechanism suggested that (i) chemical reactions between EGO and PVA matrix; (ii) a mass of negative potential sites from the interface of PVA/EGO composites made LDHs sheets easily adsorbing; (iii) oxygen-containing groups from EGO and LDHs absorbed mass of heat during combustion; (iv) the compact char residues on the surface of aerogels acting as barriers suppressed smoke and prevented PVA matrix from further combustion. Therefore, electrostatic adsorption as a facile production process was paved for meeting the compression resistance, flame-retardant, heat-insulating, and smoke-suppressed requirements of PVA aerogels in this work.

Flexible fabrication chitosan-polyamidoamine aerogels by one-step method for efficient adsorption and separation of anionic dyes

Chitosan in situ grown polyamidoamine (CTS-Gx PAMAM (x = 0, 1, 2, 3)) aerogels were fabricated by a facile one-step freeze-drying method, with glutaraldehyde serving as a crosslinker. The three-dimensional skeletal structure of aerogel provided numerous adsorption sites and accelerated the effective mass transfer of pollutants. The adsorption kinetics and isotherm studies of the two anionic dyes were consistent with the pseudo-second-order and Langmuir models, indicating that the removal of rose bengal (RB) and sunset yellow (SY) was a monolayer chemisorption process. The maximum adsorption capacity of RB and SY reached 370.28 mg/g and 343.31 mg/g, respectively. After five adsorption-desorption cycles, the adsorption capacities of the two anionic dyes reached 81.10% and 84.06% of the initial adsorption capacities, respectively. The major mechanism between the aerogels and dyes was systematically investigated based on using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy-dispersive spectroscopy analyses, confirming that electrostatic interaction, hydrogen bonding and van der Waals interactions were the main driving forces for the superior adsorption performance. Furthermore, the CTS-G2 PAMAM aerogel exhibited good filtration and separation performance. Overall, the novel aerogel adsorbent possesses excellent theoretical guidance and practical application potential for the purification of anionic dyes.

Alginate-bentonite composite decorated by chitosan-folate conjugate for the oral delivery of 5-Fluorouracil

In this work, a novel alginate-modified Na-Bentonite clay composite (APTSB-AL) was synthesized via an ionotropic gelation technique for the controlled delivery of 5-Flurouracil. Characterization of the composite was performed using Fourier transform infrared spectroscopy (FTIR): X-ray diffraction (XRD): scanning electron microscopy (SEM) etc. In order to acquire the targeted drug delivery, the composite was covered by chitosan-folate conjugate (APTSB-AL-CSFA). The freeze-drying method was adopted to avoid the leakage of water-soluble drug molecules during the drying process. The maximum swelling of the composite was found to be at pH 6.8 and the maximum drug release was at pH 7.4. The release kinetics mechanism was explained by the Korsmeyer-Peppas kinetic model. In order to find out the material toxicity, the biocompatibility assay in a normal cell line of mouse fibroblast (L929) was carried out. At the concentration of 2.5 μg/ml, the cell toxicity was negligible. At the high concentration level of 40.0 μg/ml, the cell viability was not less than 70.0 %. The in vitro cytotoxicity of the drug-loaded composite was studied in Human Colorectal Adenocarcinoma cells and the findings indicated good biocompatibility of the composite. At the concentration of 2.5 μg/ml of the drug-loaded composite (FU-L-APTSB-AL-CSFA): the cell toxicity was found to be less than 50%. And at the high concentration level of 40.0 μg/ml, the cell viability was found to be less than 10%, indicating the targeting action of the loaded composite.

Lithium Manganese Sulfates as a New Class of Supercapattery Materials at Elevated Temperatures.

To make supercapattery devices feasible, there is an urgent need to find electrode materials that exhibit a hybrid mechanism of energy storage. Herein, we provide a first report on the capability of lithium manganese sulfates to be used as supercapattery materials at elevated temperatures. Two compositions are studied: monoclinic Li2Mn(SO4)2 and orthorhombic Li2Mn2(SO4)3, which are prepared by a freeze-drying method followed by heat treatment at 500 °C. The electrochemical performance of sulfate electrodes is evaluated in lithium-ion cells using two types of electrolytes: conventional carbonate-based electrolytes and ionic liquid IL ones. The electrochemical measurements are carried out in the temperature range of 20-60 °C. The stability of sulfate electrodes after cycling is monitored by in-situ Raman spectroscopy and ex-situ XRD and TEM analysis. It is found that sulfate salts store Li+ by a hybrid mechanism that depends on the kind of electrolyte used and the recording temperature. Li2Mn(SO4)2 outperforms Li2Mn2(SO4)3 and displays excellent electrochemical properties at elevated temperatures: at 60 °C, the energy density reaches 280 Wh/kg at a power density of 11,000 W/kg. During cell cycling, there is a transformation of the Li-rich salt, Li2Mn(SO4)2, into a defective Li-poor one, Li2Mn2(SO4)3, which appears to be responsible for the improved storage properties. The data reveals that Li2Mn(SO4)2 is a prospective candidate for supercapacitor electrode materials at elevated temperatures.

Rational construction of 3D recyclable g-C3N4 when encapsulated by cellulose/graphene oxide hybrid aerogels for efficient contaminant removal

The low quantum efficiency and poor recyclability of g-C3N4 limit its further application. Cellulose/graphene oxide hybrid aerogels have the potential to solve these drawbacks owing to their porous structure and enhanced electronic conductivity. Thus recyclable g-C3N4/cellulose/graphene oxide composites (CNxCEG-y) were developed by using facile freeze-dried method in this study. The network-interleaving structure, components and efficient degradation rate were investigated using a host of systematic technologies. The excellent degradation capacity of this approach is primarily resulted from the synergistic effect of their adsorption-photocatalysis dual properties, unique porous structure, larger specific surface area, enhanced light absorption capacity and smaller charge transfer resistance. In addition, reactive species of h+ and •O2-, especially the dominant role of h+, were identified during the reaction procedure. This research can provide a novel strategy for designing artificial contaminant disposal systems with high efficiency and superior reusability.

Development of cellulose/hydroxyapatite/TiO2 scaffolds for efficient removal of lead (II) ions pollution: Characterization, kinetic analysis, and artificial neural network modeling

The utilization of nano-biodegradable composites for removing pollutants and heavy metals in aquatic environments has been widespread. This study focuses on synthesizing cellulose/hydroxyapatite nanocomposites with titanium dioxide (TiO2) via the freeze-drying method for the adsorption of lead ions in aquatic environments. The physical and chemical properties of the nanocomposites, including structure, morphology, and mechanical properties, were analyzed through FTIR, XRD, SEM, and EDS. In addition, parameters affecting the adsorption capacity, such as time, temperature, pH, and initial concentration, were determined. The nanocomposite exhibited a maximum adsorption capacity of 1012 mg⸱g−1, and the second-order kinetic model was found to govern the adsorption process. Additionally, an artificial neural network (ANN) was created using weight percentages (wt%) of nanoparticles included in the scaffold to predict the mechanical behavior, porosity, and desorption of the scaffolds at various weight percentages of hydroxyapatite (nHAP) and TiO2. The results of the ANN indicated that the incorporation of both single and hybrid nanoparticles into the scaffolds improved their mechanical behavior and desorption, as well as increased their porosity.

Boron-doped porous waste silicon/carbon composite with improved performance for lithium-ion batteries

With the rapid development of the photovoltaic (PV) industry, the amount of PV silicon (Si) produced by cutting is also increased. Therefore, recycling PV Si produced by PV cutting is critical. Herein, we used PV Si to design a kind of boron-doped porous silicon/carbon (B-Si/C) composites through acid etching and freeze-drying methods. The B-Si/C has a uniform size (25–35 nm), rich pores and good dispersibility. Porous Si doped with B can shorten the ion transmission distance. Simultaneously, the outer carbon layer of B-Si/C can relieve the volume expansion of the Si nanoparticles and prevent the Si nanoparticles from agglomerating during charge–discharge cycles. When applied as anodes for lithium-ion batteries (LIBs), the B-Si/C exhibits superior electrochemical performance with a commendable capacity of 1240 mA h g−1 at 420 mA g−1 after 100 cycles. It is very viable environmentally and economically to produce advanced high-capacity anode materials for LIBs using PV Si.

Isolation, identification and conservation of bacteria of biotechnological interest

Introduction. The evaluation of microbial biodiversity is an important step in the process of its conservation, and the identification of bacterial strains of biotechnological interest allows their application as support for the development of sustainable agriculture technologies.
 Material and methods. From the lakes of the "La Izvor" park, 213 types of bacteria, 148 of them pathogenic, were isolated. From the non-pathogenic ones, those of biotechnological interest were determined the enzymatic properties, antimicrobial activity and were identified by molecular biological methods after that preserved by the lyophilization method with the determination of viability before and after lyophilization.
 Results. The microbial biodiversity of the "La Izvor" lakes was studied, 213 types of bacterial colonies were isolated in pure culture, which of 148 proved to be enteropathogenic belonging to the genera Escherichia, Salmonella, Shigella, Enterobacter and Klebsiella as and other strains from the Enterobacteriaceae family. The purpose of the research consisted in the isolation and identification of non-pathogenic bacteria of biotechnological interest with different properties that could serve to elaborate and improve the development of sustainable agriculture technologies. Nineteen strains with enzymatic properties and high antifungal activity against phytopathogenic fungi, were selected for molecular identification, passported, submitted to the NCNM and preserved by the lyophilization method for determination valuable properties for a long time.
 Conclusions. In the lakes of "La Izvor" park there is a very large variety of microorganisms, especially bacteria, some of which are enteropathogenic bacteria that can cause diseases in the population. Selected non-pathogenic strains stored in the NCNM can be applied against phytopathogens that cause dangerous disease and damage in agriculture major crops. As a result of lyophilization, we found that all strains showed the osmotic and thermal shocks tolerance and have a viability over 75%.
 Key words: microbial biodiversity, isolation, identification, conservation.

Enhanced Lithium Storage Performance in Si/MXene Porous Composites

As a potential negative electrode material for lithium-ion batteries (LIBs), silicon has a relatively high specific lithium storage capacity. However, the large volume change during the cycle may result in the isolation with the current collector and therefore the rapid capacity decay during cycling. The poor electric conductivity of the silicon limits the high-power density application in LIBs. To meet the above challenges, a stable Si/Ti3C2Tx composite material was designed. Si nanoparticles are bonded with -NH2 group so that the silicon surface has a positive charge, which can then be electrostatic self-assembly with negatively charged MXene nanosheets in a facile freeze-drying method. Silicon nanoparticles were anchored on the surface or inside the interspace of the MXene nanosheets, which could improve the conductivity of the composites. The composite material (NH2-Si/MXene) presented a stable and porous structure with extra room for silicon expansion and plentiful channels for carrier transportation. Benefiting from the improved structural stability and enhanced charge storage dynamics, the discharge capacity of NH2-Si/MXene is 1203.3 mAh g−1 after 100 cycles at 200 mA g−1. These results provide new insights for the application of silicon-based negative electrode materials in high-energy-density LIBs.

Multidimensional nanomaterials synergistic polyimide nanofiber/MXene/NiFe2O4 hybrid aerogel for high-performance microwave absorption

Microwave absorption materials are urgently demanded to control the increasing electromagnetic radiation pollution, but it remains a great challenge to achieve high-performance absorption through ingenious structure design and reasonable multicomponent strategy. Herein, a three-dimensional (3D) hybrid aerogel constructed from multidimensional nanomaterials was fabricated via freeze-drying method followed by heating treatment process. Therein, 2D Ti3C2Tx MXene nanosheets and 0D NiFe2O4 nanoparticles act as the electrical-magnetic skeleton of aerogel, while 1D polyimide nanofibers and polydimethylsiloxane as internal supporting parts and external crosslinker, respectively. The macroscopic interconnected porous structure coupled with the microscopic multiphase heterointerfaces are beneficial to forming the perfect impedance matching and superior dielectric/magnetic synergistic loss effects. Thus, the microwave absorption performance of this hybrid aerogel achieves thin thickness (1.5 mm), light weight (∼9.6 mg/cm3), wide effective absorption bandwidth (−6.24 GHz), and strong absorption (minimum reflection loss of −64.87 dB, 99.99996% microwave absorption) features. Besides, this aerogel also exhibits exceptional structural robustness and mechanical properties, as well as good hydrophobicity and thermal insulation characteristics, which ensure its stable and durable microwave absorption application in complex environments. This study effectively integrates multidimensional nanomaterials into a host–guest aerogel system, providing a valuable strategy for constructing high-performance microwave absorption materials.

Improving the comprehensive properties of chitosan-based thermal insulation aerogels by introducing a biobased epoxy thermoset to form an anisotropic honeycomb-layered structure

Naturally-derived aerogels have attracted considerable attention owing to their good biocompatibility, biodegradability and sustainability, but their weak mechanical properties largely limit their applications in various fields. Herein, we proposed the use of a directional freeze-drying method to prepare an anisotropic honeycomb three-dimensional porous aerogel with water-soluble chitosan (CS) as a rigid skeleton and water-soluble biobased epoxy resin as cross-linked hard segments, which had low volume shrinkage and density of 13.9 % and 34.3 mg/cm3, respectively. The resultant aerogel had anisotropic mechanical properties, such as rigidity in the axial direction with a maximum axial modulus of 6.71 MPa, which was 51.6 times larger than that of the pure chitosan aerogel, demonstrating a good compressive elasticity in the radial direction. It also had anisotropic thermal management properties, with a lower thermal conductivity in the radial direction than in the axial direction, down to 0.029 W/mK. The introduction of biobased epoxy resin improved the overall thermal stability, flame retardancy, and increased the biomass content in the aerogel, reducing the carbon footprint of the material. This study paves the way for the construction of a special graded porous, structurally and functionally integrated thermal insulation aerogel, which is of great significance for the development of new thermal insulation materials.

Development of an Alcohol Dilution-Lyophilization Method for the Preparation of mRNA-LNPs with Improved Storage Stability.

The lipid nanoparticle (LNP) is one of the promising nanotechnologies for the delivery of RNA molecules, such as small interfering RNA (siRNA) and messenger RNA (mRNA). A series of LNPs that contain an mRNA encoding the antigen protein of SARS-CoV-2 were already approved as RNA vaccines against this infectious disease. Since LNP formulations are generally metastable, their physicochemical properties are expected to shift toward a more stable state during the long-time storage of suspensions. The current mRNA vaccines are supplied in the form of frozen formulations with a cryoprotectant for preventing deterioration. They must be stored in a freezer at temperatures from -80 °C to -15 °C. It is thought that therapeutic applications of this mRNA-LNP technology could be accelerated if a new formulation that permits mRNA-LNPs to be stored under milder conditions were available. We previously reported on a one-pot method for producing siRNA-encapsulated LNPs by combining freeze-drying technology with the conventional alcohol dilution method (referred to herein as the "alcohol dilution-lyophilization method"). In this study, this method was applied to the preparation of mRNA-LNPs to provide a freeze-dried formulation of mRNA LNPs. The resulting formulation can be stored at 4 °C for at least 4 months.

Curcumin nanocrystals self-stabilized Pickering emulsion freeze-dried powder: Development, characterization, and suppression of airway inflammation

Curcumin, a diketone compound extracted from turmeric's rhizome, is an effective anti-inflammatory drug with multiple pharmacological activities. However, its low oral bioavailability due to its low water solubility and permeability severely limits its clinical applications. Therefore, to enhance the oral bioavailability of curcumin, further enhance its anti-inflammatory effects, and improve its potential in the treatment of airway inflammation, a curcumin nanocrystalline self-stabilizing Pickering emulsion (Cur-NSSPE) was prepared through high-pressure homogenization. Next, Cur-NSSPE was dried using a freeze-drying method to produce Cur-NSSPE-FDP. The prepared Cur-NSSPE and Cur-NSSPE-FDP were physically characterized. The release behavior and transmembrane transport capability of Cur-NSSPE-FDP in vitro were evaluated. Pharmacokinetic study was performed to evaluate its oral bioavailability. The anti-inflammatory effects of Cur-NSSPE-FDP in vivo and in vitro were investigated using RAW 264.7 macrophage inflammation model induced by LPS and IFN-γ and asthma model in BALB/c mice induced by OVA. The average particle size of Cur-NSSPE was (163.66 ± 6.78) nm, and the average drug content was (2.78 ± 0.01) mg/mL. The transmission electron microscopy results showed that the droplets were spherical in shape with a relatively uniform size, and the curcumin nanocrystals formed a spherical core-shell structure wrapped at the interface of the droplets. The scanning electron microscopy showed that Cur-NSSPE-FDP was a neatly arranged, having loose and porous network structure. Furthermore, it can significantly improve the cumulative release of curcumin in vitro and improve oral bioavailability in rats, increase the uptake of RAW264.7 and Caco-2 cells, promote the transport of curcumin across Caco-2 cells, significantly inhibit the expression of inflammatory factors NO, IL-6, TNF-a, MDA, IgE and ICAM-1, and improve the expression of IL-10 and SOD. These results indicated that the curcumin nanocrystalline self-stabilizing Pickering emulsion-freeze dried powder improved the oral bioavailability of curcumin and enhanced its therapeutic effect in airway inflammation.

Hemolysis and hypersensitive tests ease culture collection management of antagonistic bacteria

A biosafety assessment is a crucial first step in the management of microbial culture collection to screen and determine unexpected potential plant and human pathogenic bacteria. It is common to collect and store as many fresh culture collections from natural resources before being further evaluated for antagonist bacteria. As a result, a bulk of isolates must be preserved which required more effort and budget. Safety evaluations based on the hemolysis and hypersensitive reactions offer simple tests to ease culture collection management of antagonist bacteria. The study aimed to evaluate the safety of bacterial culture collection for their hemolysis and hypersensitive reactions. Ninety-five isolates of rhizosphere and endophytic bacterial isolates from the culture collections of the Department of Plant Protection-IPB University, Indonesian Industrial and Beverages Crops Research Institute, and Indonesian Spice and Medicinal Crops Research Institute, were evaluated their safety using the hemolysis and hypersensitive tests. The hemolysis test was conducted using blood agar media, from which isolates with a negative (?) reaction were then tested for the hypersensitivity reaction on tobacco leaves. Bacterial isolates passed from both hemolysis and hypersensitivity tests were then preserved by the lyophilization method for long-term storage of culture collection. Based on the hemolysis test, 68 out of 95 bacterial isolates (71.57%) were found to be positive (? or ?) reactions. The hypersensitive test showed that 22 of 27 negative hemolysis isolates did not trigger hypersensitivity reactions in tobacco leaves, therefore, they were preserved by lyophilization. The study indicated that a high number of bacterial isolates in the present collection, 68 positive hemolysis, and 5 hypersensitive, need to be re-evaluated due to their safety concerns. The present study highlights the importance of biosafety tests performed in an early stage before the to permanent collection of antagonist isolates.

Multi-interfacial engineering in the hierarchical self-assembled micro-nano dielectric aerogel for wide-band absorption and low infrared emissivity

Radar-infrared (IR) compatible stealth can satisfy the characteristics of excellent electromagnetic wave attenuation property and low infrared emissivity. However, concurrently satisfying these demands is still a great challenge at present. Herein, multi-interfacial engineering strategy was proposed for the preparation of radar-IR compatible stealth materials. ZnO has a high electron binding energy and a large band gap at room temperature, and doping with sulphide can increase the concentration of unconstrained carriers. Therefore, bimetallic sulphide aerogels loaded with ZnO were prepared by means of carbonization and vulcanization, combined with freeze-drying method. When the filling ratio is 20 %, an absorption bandwidth (fe) of 6.62 GHz at a matching thickness of 2.0 mm and a reduction in IR emissivity from 0.920 to 0.539 in the 8–14 μm band are achieved. This work provides a guidance to design and synthesize high-performance absorbers by multi-interfacial engineering for IR-radar compatible stealth application.

The compressive strength and static biodegradation rate of chitosan-gelatin limestone-based carbonate hydroxyapatite composite scaffold

Background: One of the main components in tissue engineering is the scaffold, which may serve as a medium to support cell and tissue growth. Scaffolds must have good compressive strength and controlled biodegradability to show biological activities while treating bone defects. This study uses Chitosan-gelatin (C–G) with good flexibility and elasticity and high-strength carbonate hydroxyapatite (CHA), which may be the ideal scaffold for tissue engineering. Purpose: To analyze the compressive strength and static biodegradation rate within various ratios of C–G and CHA (C–G:CHA) scaffold as a requirement for bone tissue engineering. Methods: The scaffold is synthesized from C–G:CHA with three ratio variations, which are 40:60, 30:70, and 20:80 (weight for weight [w/w]), made with a freeze-drying method. The compressive strengths are then tested. The biodegradation rate is tested by soaking the scaffold in simulated body fluid for 1, 3, 7, 14, and 21 days. Data are analyzed with a one-way ANOVA parametric test. Results: The compressive strength of each ratio of C–G:CHA scaffold 40:60 (w/w), 30:70 (w/w), and 20:80 (w/w), consecutively, are 4.2 Megapascals (MPa), 3.3 MPa, 2.2 MPa, and there are no significant differences with the p= 0.069 (p>0.05). The static biodegradation percentage after 21 days on each ratio variation of C–G:CHA scaffold 40:60 (w/w), 30:70 (w/w), and 20:80 (w/w) is 25.98%, 24.67%, and 20.64%. One-way ANOVA Welch test shows the result of the p-value as p<0.05. Conclusion: The compressive strength and static biodegradation of the C–G:CHA scaffold with ratio variations of 40:60 (w/w), 30:70 (w/w), and 20:80(w/w) fulfilled the requirements as a scaffold for bone tissue engineering.

The characteristics of swelling and biodegradation tests of bovine amniotic membrane-hydroxyapatite biocomposite

Background: A good biocomposite is a structure that can provide opportunities for cells to adhere, proliferate, and differentiate. It is affected by the characteristics of a material. As bone tissue regeneration occurs, biomaterials must have a high swelling ability and low biodegradability. The high swelling capability will have a larger surface area that can support maximal cell attachment and proliferation on the biocomposite surface, which accelerates the regeneration process of bone defects. Purpose: The study aimed to analyze the characteristics of swelling and biodegradation of bovine amniotic membrane-hydroxyapatite (BAM-HA) biocomposite with various ratios. Methods: The BAM-HA biocomposite with a ratio of 30:70, 35:65, and 40:60 (w/w) was synthesized using a freeze-dry method. The swelling test was done by measuring the initial weight and final weight after being soaked in phosphate-buffered saline for 24 hours and the biodegradation test was done by measuring the initial weight and final weight after being soaked in simulated body fluid for seven days. Results: The swelling percentage of BAM-HA biocomposite at each ratio of 30:70, 35:65, and 40:60 (w/w) was 303.90%, 477.94%, and 574.19%. The biodegradation percentage of BAM-HA biocomposite at each ratio of 30:70, 35:65, and 40:60 was 9.43%, 11.05%, and 12.02%. Conclusion: The BAM-HA biocomposite with a ratio of 40:60 (w/w) has the highest swelling percentage while the 30:70 (w/w) ratio has the lowest percentage of biodegradation.

High-Performance Aqueous Zinc-Ion Batteries Based on Multidimensional V2O3 Nanosheets@Single-Walled Carbon Nanohorns@Reduced Graphene Oxide Composite and Optimized Electrolyte.

The drawbacks of poor electronic conductivity and structural instability during the cycling process limit the electrochemical property of vanadium-based cathode materials for aqueous zinc-ion batteries. In addition, continuous growth and accumulation of zinc dendrites can puncture the separator and cause an internal short circuit in the battery. In this work, a unique multidimensional nanocomposite is designed by a facile freeze-drying method with subsequent calcination, consisting of V2O3 nanosheets and single-walled carbon nanohorns (SWCNHs) crosslinked together and wrapped by reduced graphene oxide (rGO). The multidimensional structure can largely enhance the structural stability and electronic conductivity of the electrode material. Besides, additive Na2SO4 in the ZnSO4 aqueous electrolyte not only prevents the dissolution of cathode materials but also suppresses the Zn dendrite growth. After considering the influence of additive concentration on ionic conductivity and electrostatic force for electrolyte, V2O3@SWCNHs@rGO electrode delivers a high initial discharge capacity of 422 mAh g-1 at 0.2 A g-1 and a high discharge capacity of 283 mAh g-1 after 1000 cycles at 5 A g-1 in 2m ZnSO4 + 2m Na2SO4 electrolyte. Experimental techniques reveal that the electrochemical reaction mechanism can be expressed as the reversible phase transformation between V2O5 and V2O3 with Zn3(VO4)2.