Freeze-drying Technique Research Articles

Inhaled Dry Powder Formulation of Tamibarotene, a Broad‐Spectrum Antiviral against Respiratory Viruses Including SARS‐CoV‐2 and Influenza Virus

AbstractIn response to the epidemic and pandemic threats caused by emerging respiratory viral infections, a safe and efficient broad‐spectrum antiviral therapy at early onset of infection can significantly improve patients’ outcome. Inhaled dry powder is easy to administer and delivers antiviral agent directly to the primary site of infection, thereby minimizing systemic side effects. Here, spray freeze drying (SFD) technique is employed to formulate tamibarotene, a retinoid derivative with broad‐spectrum antiviral activity, as inhalable powder. The SFD tamibarotene powder exhibits desirable physicochemical and aerodynamic properties for inhalation. Pulmonary delivery of tamibarotene powder results in rapid absorption and higher bioavailability compared with intraperitoneal injection of unformulated drug in animals. More importantly, inhalation or intranasal delivery of SFD tamibarotene formulation displays broad‐spectrum antiviral activity against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), Middle East respiratory syndrome coronavirus, and pandemic 2009 influenza A virus (H1N1) in mouse and hamster models by targeting lower or upper airways, and the efficacy is comparable or superior to the commercially available antivirals remdesivir and zanamivir against specific virus. These results present a promising strategy to combat various respiratory viral infections including SARS‐CoV‐2 and influenza virus, or even co‐infection.

Production of proficiency test items containing bacteria in chicken matrix using freeze-drying technique

Introdução: A participação em ensaios de proficiência (EP) é utilizada para avaliar a competência de laboratórios de ensaio e calibração. Objetivo: Avaliar a viabilidade da técnica de liofilização na produção de seis lotes de itens de EP, dois contendo Escherichia coli, dois contendo Bacillus cereus e Staphylococcus aureus concomitantemente, e dois contendo Salmonella Enteritidis em matriz frango desfiado cozido. Método: Foram realizados testes de homogeneidade segundo o protocolo harmonizado e de estabilidade em longo prazo pelo modelo clássico e curto prazo pelo modelo isócrono segundo a ISO Guide 35. Resultados: Todos os lotes produzidos foram considerados suficientemente homogêneos. No estudo de estabilidade em longo prazo, todos os lotes se apresentaram suficientemente estáveis nas temperaturas de -80 ± 10ºC e -20 ± 4ºC, exceto o lote contendo B. cereus e S. aureus. Os outros lotes apresentaram estabilidade por pelo menos 126 dias a -80 ± 10ºC e 84 dias a -20 ± 4ºC. Na avaliação da estabilidade em curto prazo, foram analisados apenas os lotes suficientemente estáveis no estudo em longo prazo. Os lotes foram suficientemente estáveis nas temperaturas de 5 ± 3ºC e 35 ± 2ºC, com exceção do lote contendo Salmonella Enteritidis a 35 ± 2ºC, devido ao decréscimo significativo da concentração celular. Conclusões: A técnica de liofilização foi satisfatória para produção de itens de ensaio contendo E. coli e Salmonella Enteritidis em matriz frango viáveis para utilização em um EP, sendo que o lote contendo Salmonella Enteritidis deve ser transportado aos laboratórios participantes em temperatura ≤ 8ºC por até quatro dias. Lotes contendo S. aureus e B. cereus, simultaneamente, apresentaram estabilidade insuficiente, indicando que a produção de lotes individuais contendo cada bactéria individualmente é necessária.

Enhanced Cellular Uptake in an Electrostatically Interacting Fucoidan-L-Arginine Fiber Complex.

Fucoidan is an abundant marine sulfated polysaccharide extracted from the cell wall of brown macroalgae (seaweed). Recently, fucoidan has been highly involved in various industrial applications, such as pharmaceuticals, biomedicals, cosmetics, and food. However, the presence of a sulfate group (negative surface charge) in the fucoidan structure limits its potential and biological activity for use in biomedical applications during cellular uptake. Thus, we aimed to improve the uptake of fucoidan by using an L-arginine uptake enhancer within an in vitro study. A Fucoidan–L-Arginine (Fuc-L-Arg) fiber complex was prepared via α-helical electrostatic interactions using a freeze-drying technique and confirmed using field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. In addition, fucoidan was conjugated with cyanine 3 (Cy3) dye to track its cellular uptake. Furthermore, the results of Fuc-L-Arg (1:1, 1:2.5) complexes revealed biocompatibility >80% at various concentrations (5, 10, 25, 50, 100 µg/mL). Owing to the higher internalization of the Fuc-L-Arg (1:5) complex, it exhibited <80% biocompatibility at higher concentrations (25, 50, 100 µg/mL) of the complex. In addition, improved cellular internalization of Fuc-L-Arg complexes (1:5) in HeLa cells have been proved via flow cytometry quantitative analysis. Hence, we highlight that the Fuc-L-Arg (1:5) fiber complex can act as an excellent biocomplex to exhibit potential bioactivities, such as targeting cancers, as fucoidan shows higher permeability in HeLa cells.

Improved water solubility of quercetin by preparing complexation with cyclodextrins in binary solvent

The antioxidant capacity of polyphenols have been widely used in food and pharmaceutical industries. Quercetin (Quer) is a polyphenolic flavonoid that shows several biological effects such as antioxidant, antitumor, antibacterial and antiproliferative effects both in-vitro and in-vivo. However, the solubility of quercetin in water is poor. Thus, it is essential to improve solubility of quercetin in pharmaceuticals by making its complexation with other compounds. In this study, the synthesis of the 2-hydroxypropyl-β-cyclodextrin complex with quercetin (Quer-HPβCD) in the form of nanoparticles in water-ethanol solvents has been carried out. The results showed that the obtained yield of (Quer-HPβCD) complexation in binary solvent was greater than that in pure water. The highest Y value was 80% in a binary solvent with 20% v/v of ethanol. The composition, morphology, structural and thermodynamic properties of the nanoparticles Quer-HPβCD have been determined. This study demonstrated that using mixed water- ethanol solvent and lyophilization technique was able to produce quercetin nanoparticles with significantly smaller particle size. The nanoparticles have a spherical shape with an average size of about 40-60 nm. The results of the phase solubility diagram showed that in water the solubility of quercetin increased and linearly depended on the concentration of host’s molecule while Quer and HP-βCD obtained a 1:1 stoichiometric complex. The stability constant of (Quer-HPβCD) complex was found to be logK = 2.56. The Gibbs energy change of the complexation reaction was found to be -14.60 kJ/mol.

Development of Biopolymeric Hybrid Scaffold-Based on AAc/GO/nHAp/TiO2 Nanocomposite for Bone Tissue Engineering: In-Vitro Analysis.

Bone tissue engineering is an advanced field for treatment of fractured bones to restore/regulate biological functions. Biopolymeric/bioceramic-based hybrid nanocomposite scaffolds are potential biomaterials for bone tissue because of biodegradable and biocompatible characteristics. We report synthesis of nanocomposite based on acrylic acid (AAc)/guar gum (GG), nano-hydroxyapatite (HAp NPs), titanium nanoparticles (TiO2 NPs), and optimum graphene oxide (GO) amount via free radical polymerization method. Porous scaffolds were fabricated through freeze-drying technique and coated with silver sulphadiazine. Different techniques were used to investigate functional group, crystal structural properties, morphology/elemental properties, porosity, and mechanical properties of fabricated scaffolds. Results show that increasing amount of TiO2 in combination with optimized GO has improved physicochemical and microstructural properties, mechanical properties (compressive strength (2.96 to 13.31 MPa) and Young’s modulus (39.56 to 300.81 MPa)), and porous properties (pore size (256.11 to 107.42 μm) and porosity (79.97 to 44.32%)). After 150 min, silver sulfadiazine release was found to be ~94.1%. In vitro assay of scaffolds also exhibited promising results against mouse pre-osteoblast (MC3T3-E1) cell lines. Hence, these fabricated scaffolds would be potential biomaterials for bone tissue engineering in biomedical engineering.

Encapsulation of Freeze-dried Propolis Powder: Study of in vitro Disintegration and Dissolution

Abstract: Propolis is a resinous material collected by bees from various plant sources. Propolis has been used since ancient times for medicinal purposes. In this study, the propolis extracts were dried using a freeze-drying technique to preserve its medicinal properties. The effect of different freezing temperatures on the yield and propolis powder flow ability characteristics was evaluated. The potential of propolis powder to be encapsulated in hard gelatin capsules and hard hydroxypropyl methylcellulose (HPMC) capsules were investigated. The mass uniformity, in vitro disintegration and dissolution performance of the propolis powder in hard gelatine capsules and hard HPMC capsules were determined after encapsulation. The amount of propolis powder produced after freeze-drying decreased with decreasing of freezing temperature from -50°C to -80°C. Propolis powder obtained at -80°C of freezing temperature showed excellent flow ability characteristics. The average mass of propolis powder in hard gelatine capsules and the propolis powder in hard HPMC capsules was 0.5578 ± 0.019g and 0.5559 ± 0.020 g, respectively. In vitro disintegration test showed that the propolis powder that was loaded into the hard gelatine capsules disintegrated faster than the propolis powder loaded into the hard HPMC capsules, which were 1.7 to 7.8 min and 3.7 to 8.4 min in all four media solutions. Among the dissolution media tested, 1 % SLS in water showed the highest release of flavonoid. The studies of an encapsulated form of propolis powder are recommended prior to the release of a dietary supplement or clinical trial investigational product to ensure its efficacy. Key words: Propolis, Trigona thoracica, Freeze-drying, Capsule, Disintegration, Dissolution.

Quality of a powdered grapefruit product formulated with biopolymers obtained by freeze-drying and spray-drying.

Freeze-drying and spray-drying are two techniques used to produce dehydrated food products. Both techniques are easy to use and offer high sensory, nutritive value, and functional quality to foods. However, both processes become difficult for foods with high sugar and acid content, such as fruits. This is because these products, once dehydrated, moisten quickly, causing a change in their physical properties, mainly in the mechanical aspects related to the start of a caking phenomenon. Therefore, incorporating high molecular weight biopolymers that act as facilitators or processors, prevent the structural collapse of the product. The aim of this study was to select the best process, between freeze-drying or spray-drying, to obtain a powdered grapefruit product with the higher quality. The impact of the biopolymers used to stabilize the powdered product was also tested. The properties analyzed were the solubility, wettability, hygroscopicity, porosity, and color of the powder together with the flow behavior, both in air and water. The results of this study show that using the freeze-drying technique, products have a better flow behavior, greater porosity, and a color more like fresh grapefruit. Biopolymers, especially when in combination, have a positive effect on the quality parameters studied. PRACTICAL APPLICATION: The results of this study allow freeze-drying to be proposed as a process to obtain a grapefruit product with better properties, both powdered and rehydrated, than that obtained by spray-drying. On the other hand, although the incorporation of biopolymers is necessary to facilitate the process and stabilize the product, no significant differences have been found between the different formulations tested, although it seems that their combination favours some of the properties of the powder, such as solubility, hygroscopicity, wetting time and dispersibility.

3D-printing-assisted fabrication of chitosan scaffolds from different sources and cross-linkers for dental tissue engineering.

The aim of the present study was to fabricate and characterise chitosan scaffolds from animal and fungal sources, with or without gelatine as a co-polymer, and cross-linked to 3-glycidyloxyproply trimethoxysilane (GPTMS) or genipin for application in dental root tissue engineering. Chitosan-based scaffolds were prepared by the emulsion freeze-drying technique. Scanning electron microscopy (SEM) and nano-focus computed tomography (nano-CT) were used to characterise scaffold microstructure. Chemical composition and cross-linking were evaluated by Fourier transform infrared-attenuated total reflectance spectroscopy. Compression tests were performed to evaluate scaffold mechanical properties. Scaffold degradation was evaluated by gravimetric method and SEM. Scaffold bioactivity immersed in simulated body fluid was evaluated by SEM, with associated electron dispersive X-ray spectroscopy, and apatite formation was examined by X-ray diffraction. Finally, human dental pulp stem cells (hDPSCs) viability was evaluated. The fabrication method used was successful in producing scaffolds with organised porosity. Chitosan source (animal vs. fungal), co-polymerisation with gelatine and cross-linking using GPTMS or genipin had a significant effect on scaffold properties and hDPSCs response. Chitosan-genipin (CS-GEN) scaffolds had the largest pore diameter, while the chitosan-gelatine-GPTMS (CS-GEL-GPTMS) scaffolds had the smallest. Animal chitosan-gelatine co-polymerisation increased scaffold compressive strength, while fungal chitosan scaffolds (fCS-GEL-GPTMS) had the fastest degradation rate, losing 80 % of their weight by day 21. Gelatine co-polymerisation and GPTMS cross-linking enhanced chitosan scaffolds bioactivity through the formation of an apatite layer as well as improved hDPSCs attachment and viability. Tailored chitosan scaffolds with tuned properties and favourable hDPSCs response can be obtained for regenerative dentistry applications.

Waste water of various boiled legumes as potential of radical scavenging agents

Peanut, soybean and chickpea important source of macronutrients and considered as important foodstuff in Malaysia. Boiled legumes are usually sold on by hawker on street. The water used for boiling the legumes is commonly thrown away without considering the radical scavenging potential of this so-called waste. Besides, there is lacking of awareness among the public about its nutritional benefits as part of sustainable food production aimed towards food security and nutrition. Furthermore, food antioxidants might play a significant role as physiological and dietary antioxidants which also could be a substitute for synthetic antioxidants and preservatives. Hence, this study aimed to evaluate the radical scavenging activity of the waste water from the three types of boiled legumes. The legumes were boiled in hot water and the waste water were collected. In this study, the waste water is converted into powder by means of freeze-drying technique. Radical scavenging activity was investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, while its phenolic and flavonoid contents were determined using Folin-Ciocalteu assay and aluminum chloride colorimetric assay. The waste water of peanut showed the highest percentage of DPPH inhibition at 85.03±6.91%, followed by chickpea and soybean waste water at 79.89±3.69% and 69.10±6.19%, respectively. Furthermore, the waste water of peanut also showed the lowest IC50 value of 0.503±0.05 mg/mL, followed by soybean and chickpea of 0.554 ±0.01 mg/mL and 0.697±0.04 mg/mL. On a side note, peanut waste water extract showed the highest phenolic and flavonoid contents which are 1.877±0.36 mg GAE/g and 0.736±0.01 mg CE/g, respectively, whereas chickpea showed the lowest content of both which are 0.519±0.01 mg GAE/g and 0.227±0.01 mg CE/g, respectively. As conclusion, the waste water of boiled legumes is worth to be further investigated on their radical scavenging activity using other assays and could be potentially developed into functional foods.

Preparation and characterization of carboxymethylcellulose based citric acid cross-linked magnetic aerogel as an efficient dye adsorbent

A low-cost, collectable, and efficient material is essential for adsorbing water pollution, such as dyes and heavy metal ions pollution. In this work, we proposed a novel strategy for the preparation of an efficient and collectable magnetic aerogel as adsorbent for dye. The magnetic aerogels were prepared from sodium carboxymethylcellulose (CMC) hydrogel using citric acid (CA) as the crosslinker, followed by vacuum freeze-drying technique to obtain aerogels. The effects of magnetic Fe3O4 nanoparticle contents on the adsorption properties of the aerogels were investigated. The results show that the as-prepared magnetic composite aerogels exhibit porous structure and display good adsorption and collectable performance for methylene blue (MB) in water with the removal rate of 97.5% in 6 h. The maximum compress strength and absorption capacity of the magnetic aerogel with 1 wt% Fe3O4 nanoparticle loading for MB is 0.13 MPa and 83.6 mg/g, respectively. Aerogels with Fe3O4 nanoparticles exhibited magnetism which enables the aerogels to easily collect. This excellent structure stability and collectability guarantees long-term integrity and floatability of the magnetic aerogels in water.

Development of cellulose-based prebiotic fiber from banana peel by enzymatic hydrolysis

Cellulose is a kind of dietary fiber that resists digestion and absorption in the human body. In addition to health benefits of cellulose ingestion with regard to body weight management, this fiber may also provide prebiotic activity if its solubility can be enhanced. In this study, cellulose extracted from banana peels was modified by enzymatic and diluted-acid hydrolysis in order to obtain the partially hydrolyzed cellulose, which is a water-soluble fiber, and prebiotic activity involving Lactobacillus plantarum, L. casei, and Escherichia coli was evaluated. The results revealed that enzymatic hydrolysis by Celluclast® provided higher contents of water-soluble cellulose and cellodextrins than did diluted-acid hydrolysis. The sugar pattern by thin layer chromatography also indicated that cellobiose and cellotriose significantly supported the growth and lactic acid production of probiotic strains. After enzymatic hydrolysis, the water-soluble cellulose was kept in 2 forms; 1) solution, and 2) dried powder. However, the dried powder could not be utilized as a sole carbon source by those bacteria since the lyophilization technique dramatically reduced the solubility of the sample. Interestingly, cellulose solution could promote the growth of L. plantarum TISTR2075, but it did not support the growth of E. coli TISTR073. This finding provides a positive prebiotic index value, which is higher than those from inulin, a commercially well-known prebiotic fiber. Therefore, this study presents a novel perspective on consumption of cellulose as a prebiotic fiber.

In Vitro Mechanism Assessment of Zearalenone Removal by Plant-Derived Lactobacillus plantarum BCC 47723

Zearalenone (ZEA) is a harmful secondary fungal metabolite, produced primarily by plant pathogenic fungi mostly belonging to the genus Fusarium. It is involved in reproductive disorders in animals since its structure is similar to the estrogen hormone. This induces precocious pubertal changes, fertility problems, and hyper estrogenic disorders. The main objectives of this study were to evaluate the ZEA removal capacity of plant-derived lactic acid bacteria (LAB) and to investigate the possible components and mechanisms involved in the removal of ZEA by physically and chemically treated plant-derived LAB. The bacterial cells were characterized using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), and the analysis of zeta potential, and hydrophobic index. Results revealed that 17 out of 33 plant-derived LAB exhibited ZEA removal from liquid medium. The percentage of removal ranged from 0.5–23% and Lactobacillus plantarum BCC 47723, isolated from wild spider flower pickle (Pag-sian-dorng), exhibited the highest removal. The alteration of proteins on L. plantarum BCC 47723 structure by Sodium dodecyl sulphate (SDS) treatment was positively affected on ZEA removal, whereas that of lipids on ZEA removal was negatively observed. Heat treatment influenced the higher ZEA adsorption. SEM images showed that the morphologies of modified bacterial cells were distinctly deformed and damaged when compared with untreated control. FTIR analysis indicated that the original functional groups, which included amide (C=O, C-N), carboxyl (C=O, C-O, O-H), methylene (C=C), and alcohol (O-H) groups, were not changed after ZEA adsorption. The zeta potential indicated that electrostatic interaction was not involved in the ZEA removal, while hydrophobicity was the main force to interact with ZEA. These findings can conclude that adsorption by hydrophobicity is the main mechanism for ZEA removal of plant-derived L. plantarum BCC 47723. The alteration of bacterial cell structure by heat treatment enhanced the efficiency of L. plantarum BCC 47723 for ZEA reduction. Its activity can be protected by the freeze-drying technique. Hence, plant-derived L. plantarum BCC 47723 can be considered as an organic adsorbent for ZEA reduction in food and feedstuff.

Improved Mesenchymal Stem Cell Proliferation, Differentiation, Epithelial Transition, and Restrained Senescence on Hierarchically Patterned Porous Honey Silk Fibroin Scaffolds.

We report a significant improvement of adipose-derived mesenchymal stem cells' (ADMSCs) biocompatibility and proliferation on hierarchically patterned porous honey-incorporated silk fibroin scaffolds fabricated using a combination of soft lithography and freeze-drying techniques. Parametric variations show enhanced surface roughness, swelling, and degradation rate with good pore interconnectivity, porosity, and mechanical strength for soft-lithographically fabricated biomimetic microdome arrays on the 2% honey silk fibroin scaffold (PHSF2) as compared to its other variants, which eventually made PHSF2 more comparable to the native environment required for stem cell adhesion and proliferation. PHSF2 also exhibits sustained honey release with remarkable antibacterial efficacy against methicillin-resistant Staphylococcus aureus (MRSA). Honey incorporation (biochemical cue) influences microdome structural features, that is, biophysical cues (height, width, and periodicity), which further allows ADMSCs pseudopods (filopodia) to grasp the microdomes for efficient cell-cell communication and cell-matrix interaction and regulates ADMSCs behavior by altering their cytoskeletal rearrangement and thereby increases the cellular spreading area and cell sheet formation. The synergistic effect of biochemical (honey) and biophysical (patterns) cues on ADMSCs studied by the nitro blue tetrazolium assay and DCFDA fluorescence spectroscopy reveals limited free radical generation within cells. Molecular expression studies show a decrease in p53 and p21 expressions validating ADMSCs senescence inhibition, which is further correlated with a decrease in cellular senescence-associated β galactosidase activity. We also show that an increase in CDH1 and CK19 molecular expressions along with an increase in SOX9, RUNX2, and PPARγ molecular expressions supported by PHSF2 justify the substrate's efficacy of underpinning mesenchymal to epithelial transition and multilineage trans-differentiation. This work highlights the fabrication of a naturally healing nutraceutical (honey)-embedded patterned porous stand-alone tool with the potential to be used as smart stem cells delivering regenerative healing implant.

In vitro bioaccessibility and characterisation of spent hen meat hydrolysate powder prepared by spray and freeze-drying techniques

A detailed characterisation of spent hen meat hydrolysate (SMH) powders was done in this study. Briefly, SMH was obtained by enzymatic hydrolysis of whole spent hen meat of Indian layer bird breed (BV-300) using Flavourzyme® at optimised temperature (54 °C) and pH 6.6 for 30 min. The spray-dried (SD-SMH) hydrolysate powder showed significantly (p < 0.05) higher antioxidant activity (via the DPPH assay) than the freeze-dried (FD-SMH) hydrolysate powder, possibly due to the high level of sulphur-containing amino acids, as quantified by GC–MS/MS. The FD-SMH powder exhibited a higher average particle diameter (687 nm) and lower zeta potential (0.08 mV) than the SD-SMH powder (particle diameter =545 nm and zeta potential =–10.20 mV). Morphological analysis by scanning electron microscopy (SEM) corroborated significantly (p < 0.05) higher flowability of spray-dried powder (15.24; distinct spherical structure) than the freeze-dried powder (26.55; lamellar/shrivelled structure). The higher bioaccessibility of SD-SMH than FD-SMH depicted its preserved bioactivity, even after simulated gastrointestinal digestion. Overall, SD-SMH powder exerts the potential to be used in the food industry for its potential exploitation as a functional food ingredient or for nutraceutical applications.

Biomineralization of Hydroxyethyl Cellulose/Sodium Alginate for Bone Tissue

The aim of this research is to synthesis biopolymeric materials from hydroxyethyl cellulose (HEC) (5 wt. %) blended with sodium alginate (SA) (10 wt. %) at 1:1 ratio fabricated by using freeze-drying technique. The HES/SA was treated with simulated body fluid (SBF) by immersion technique through the depositing of calcium phosphate on the scaffold’s surfaces. All scaffolds were characterizing by using field emission electron microscope (FESEM), attenuated total reflectance-Fourier infrared transform (ATR-FTIR), and thermogravimetric analysis (TGA). The FESEM images results displayed interconnected porous structure with diameter ranging from 40 to 400 μm with average apatite diameter in range of 95 nm – 148 nm. The ATR-FTIR results exhibit possible interactions between hydroxyl groups of HEC, SA and apatite groups of the scaffolds. The TGA results showed four different regions of mass losses, represents the amorphous transition temperature and water disposal, side-chain bond breaking, pyrolysis of SA and dihydroxylation behaviour of calcium phosphate, respectively. Cell-scaffolds interaction demonstrated that human fetal osteoblast (hFOB) cells differentiated and spread well on scaffolds with better cell proliferation and attachment was more prominent on HEC/SA treated with SBF. Since these biocompatible and biodegradable scaffolds showed promising results, these scaffolds could be adopted for the design of next-generation tissue-engineered bone grafts.

A novel investigation on characterization of bioactive glass cement and chitosan-gelatin membrane for jawbone tissue engineering

The aim of this work was to investigate the characterization of a bioactive glass (BG) ceramic prepared by sol–gel technique and chitosan-gelatin membranes prepared by lyophilization technique containing 0, 1 and 2 vol.% ethanol. Early-absorbing and late-absorbing bone substitutes in practice constitute the main volume of bone substitutes used by dentist and orthopedic surgeons. When the graft is to be gradually replaced by normal bone, the important issue is the duration and rate of graft absorption. The prepared samples were characterized using fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. The presence of Ag nanoparticles into bioactive glass was evaluated. Porous membranes were examined under scanning electron microscopy (SEM) to estimate the size of the pores and analysis the morphological behavior. The pore diameter could be controlled within the range 10–30 µm by adjusting the percent of ethanol. The formation of needle-like hydroxyapatite (HA) crystals on the surface of the membrane after 7 days immersion in the ringer's solution was also assessed using SEM images. The SEM images results illustrated the porous structures in the membranes. The average pore size for chitosan-gelatin membrane with 2% ethanol were 30±6.3 μm. Finally, these obtained results suggested that the developed membrane with 2% ethanol possess the prerequisites for tissue engineering and can be used for jawbone tissue engineering applications.

Effect of hexagonal structure nanoparticles on the morphological performance of the ceramic scaffold using analytical oscillation response

Porous bony scaffolds are utilized to manage the growth and migration of cells from adjacent tissues to a defective position. In the current investigation, the effect of titanium oxide (TiO2) nanoparticles on mechanical and physical properties of porous bony implants made of polymeric polycaprolactone (PCL) is studied. The bio-nanocomposite scaffolds are prepared with composition of nanocrystalline hydroxyapatite (HA) and TiO2 powder using the freeze-drying technique for different weight fractions of TiO2 (0 wt%, 5 wt%, 10 wt%, and 15 wt%). In order to identify the microstructure and morphology of the fabricated porous bio-nanocomposites, the X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscopy (SEM) are employed. Also, the biocompatibility and biodegradability of the manufactured scaffolds are examined by placing them in a simulated body fluid (SBF) for 21 days, their weight and pH changes are measured. The rate of degradation of the PCL-HA scaffold can be controlled by varying the percentage of its constituent components. Due to an increasing growth and activity of bone cells and the apatite formation on the free surface of the fabricated bio-nanocomposite implants as well as their reasonable mechanical properties, they have the potential to be used as a bone substitute. Additionally, with the aid of the experimentally extracted mechanical properties of the scaffolds, the vibrational characteristics of a beam-type implant made of the proposed porous bio-nanocomposites are explored. The results obtained from SEM image indicate that the scaffolds produced by the employed method have high total porosity (70%–85%) and effective porosity. The pore size is obtained between 60 and 200 μm, which is desirable for the growth and propagation of bone cells. Also, it is revealed that the addition of TiO2 nanoparticles leads to reduce the rate of dissolution of the fabricated bio-nanocomposite scaffolds.

Arabinoxylan/graphene-oxide/nHAp-NPs/PVA bionano composite scaffolds for fractured bone healing.

The importance of bone scaffolds has increased many folds in the last few years; however, during bone implantation, bacterial infections compromise the implantation and tissue regeneration. This work is focused on this issue while not compromising on the properties of a scaffold for bone regeneration. Biocomposite scaffolds (BS) were fabricated via the freeze-drying technique. The samples were characterized for structural changes, surface morphology, porosity, and mechanical properties through spectroscopic (Fourier transform-infrared [FT-IR]), microscopic (scanning electron microscope [SEM]), X-ray (powder X-ray diffraction and energy-dispersive X-ray), and other analytical (Brunauer-Emmett-Teller, universal testing machine Instron) techniques. Antibacterial, cellular, and hemocompatibility assays were performed using standard protocols. FT-IR confirmed the interactions of all the components. SEM illustrated porous and interconnected porous morphology. The percentage porosity was in the range of 49.75%-67.28%, and the pore size was 215.65-470.87µm. The pore size was perfect for cellular penetration. Thus, cells showed significant proliferation onto these scaffolds. X-ray studies confirmed the presence of nanohydroxyapatite and graphene oxide (GO). The cell viability was 85%-98% (BS1-BS3), which shows no significant toxicity of the biocomposite. Furthermore, the biocomposites exhibited better antibacterial activity, no effect on the blood clotting (normal in vitro blood clotting), and less than 5% hemolysis. The ultimate compression strength for the biocomposites increased from 4.05 to 7.94 with an increase in the GO content. These exciting results revealed that this material has the potential for possible application in bone tissue engineering.

Combination of rehydrated sodium caseinate aqueous solution with blackcurrant concentrate and the formation of encapsulates via spray drying and freeze drying: Alterations to the functional properties of protein

The practical applications of protein ingredients in the preservation of bioactive compounds are of research interest. In this study, an aqueous solution of sodium caseinate was combined with blackcurrant concentrate to produce novel protein ingredients using spray-drying and freeze-drying techniques. High-performance liquid chromatography results showed that both spray-drying and freeze-drying strategies effectively delivered the anthocyanins of blackcurrant concentrate. Cyanidin and delphinidin contents in spray-dried samples 71.39 ± 1.07 μg/g and 83.55 ± 1.04 μg/g, respectively, while in the freeze-dried sample, cyanidin and delphinidin contents were at 53.61 ± 0.13 μg/g and 59.55 ± 0.54 μg/g, respectively. The physical and functional properties of sodium caseinate ingredients were altered by both drying strategies and also through the addition of blackcurrant concentrate. Drying processes influenced the shape and size of particles, and ultimately altered the rehydration properties of the protein ingredients. The inclusion of blackcurrant concentrate for sodium caseinate ingredients and the spray-and freeze-drying strategies altered the physical properties (particle size distribution, bulk density, and morphology), functional properties (water-holding capacity, oil-holding capacity, foamability, and foam stability), and nutritional values of sodium caseinate ingredients, providing new options for the development and innovation of food products. Novelty impact statement The research is novel in generating sodium caseinate-based blackcurrant concentrate encapsulates by spray-drying and freeze-drying. This research advances current understanding by illustrating the modifications in protein functional properties, while maintaining bioactivity. The research could be applied in generating novel food systems for health enhancement.

Hierarchically Structured Nanocellulose-Implanted Air Filters for High-Efficiency Particulate Matter Removal

Fine particulate matter (PM) air pollution has increasingly become a global problem; thus, high-performance air filtration materials are in great demand. Herein, we first prepared a biodegradable hierarchically structured nanocellulose-implanted air filter with a high filtration capacity using a freeze-drying technique. In this hierarchically structured air filter, porous structures of corrugated paper and cellulose nanofibrils (CNFs) were used as a frame and functional fillers, respectively. The self-assembled structure of the CNF fillers could be controlled by changing the freezing temperature, CNF sizes, concentrations, and base weights. Only the CNFs with a smaller size and concentration of 0.05 wt % were able to self-assemble to well-dispersed fibril networks. With constant optimization of conditions, when the base weight went up to only 0.25 g/m2, the coverage of the corrugated paper fibers with CNF networks became perfect, and a high efficiency of 94.6% for PM0.3 removal was achieved, while maintaining a relatively low pressure drop of 174.2 Pa. All of the raw materials we used are biodegradable, nonpetroleum-based materials, contributing to sustainable development. We believe that such excellent biodegradable high-performance cellulose-based air filtration materials will provide a new direction for the application of nanocellulose in air filtration.