RESUMO
Bile salts were first used in the preparation of nanoparticles due to their stabilizing effects. As time went by, they attracted much attention and were increasingly employed in fabricating nanoparticles. It is well accepted that the physicochemical properties of nanoparticles are influential factors in their permeation, distribution, elimination and degree of effectiveness as well as toxicity. The review of articles shows that the use of bile salts in the structure of nanocarriers may cause significant changes in their physicochemical properties. Hence, having information about the effect of bile salts on the properties of nanoparticles could be valuable in the design of optimal carriers. Herein, we review studies in which bile salts were used in preparing liposomes, niosomes and other nanocarriers. Furthermore, the effects of bile salts on entrapment efficiency, particle size, polydispersity index, zeta potential, release profile and stability of nanoparticles are pointed out. Finally, we debate how to take advantage of bile salts potential for preparing desirable nanocarriers.
Assuntos
Ácidos e Sais Biliares , Nanopartículas , Lipossomos/química , Nanopartículas/química , Tamanho da PartículaRESUMO
Due to the gastrointestinal side effects, the clinical application of sinomenine hydrochloride (SH) in rheumatoid arthritis is limited. The elderly population constitutes the primary group affected by this disease, and within this demographic, there are significant variations in gastric emptying time. To reduce the influence of individual differences on drug efficacy and concurrently alleviate gastrointestinal side effects, the SH sustained-release pellets with multiple release characteristics were developed, which comprised both regular sustained-release pellets and enteric-coated sustained-release pellets. The drug-loaded layer formulation was optimized by full factorial design. With the optimal formulation, the drug-loaded pellets achieved a yield of 96.05%, an encapsulation efficiency of 83.36% for SH, a relative standard deviation of 3.26% in SH content distribution, an average roundness of 0.971 for the pellets, and the particle size span of 0.808. The pellets with a 4 h SH release profile in an acidic environment and pellets displaying 4 h acid resistance followed by an 8 h SH release behavior in the intestinal environment were individually prepared through in vitro dissolution tests. The results demonstrated stable and compliant dissolution behavior of the formulation, along with excellent stability and physical appearance. This research offers novel insights and references for the innovative formulation of SH.
Assuntos
Preparações de Ação Retardada , Liberação Controlada de Fármacos , Morfinanos , Tamanho da Partícula , Solubilidade , Morfinanos/química , Morfinanos/administração & dosagem , Química Farmacêutica/métodos , Composição de Medicamentos/métodos , Artrite Reumatoide/tratamento farmacológicoRESUMO
Mining and smelting are the main sources of soil heavy metal pollution. Leaching and release of heavy metals in soils has been extensively studied. However, there are few researches on the release behavior of heavy metals from the Angle of mineralogy of smelting slag. This study focuses on the pollution of arsenic and chromium by traditional pyrometallurgical lead-zinc smelting slag in southwest China. Based on the mineralogy of smelting slag, the release behavior of heavy metals in smelting slag was studied. As and Cr deposit minerals were identified by MLA analysis, and the weathering degree and bioavailability of As and Cr deposit minerals were analyzed. The results showed that the weathering degree of slag was positively correlated with the bioavailability of heavy metals. The leaching experiment results showed that the higher pH was beneficial to the release of As and Cr. It was found that the chemical forms of As and Cr changed from relatively stable forms to easily released forms (As5+ to As3+ and Cr3+ to Cr6+) by characterizing the metallurgical slag during leaching. In the transformation process, the S in the pyrite as the enclosing layer is eventually oxidized to SO42-, which will accelerate the dissolution of the enclosing mineral. SO42- will occupy the adsorption site of As on the mineral surface, thus reducing the adsorption amount of As on the mineral surface. Fe is finally oxidized to Fe2O3, and the increase of Fe2O3 content in the waste residue will produce strong adsorption effect on Cr6+ and slow down the release of Cr6+. The results show that the release of As and Cr is controlled by the pyrite coating.
Assuntos
Metais Pesados , Poluentes do Solo , Zinco/análise , Disponibilidade Biológica , Compostos Férricos , Chumbo/análise , Metais Pesados/análise , Minerais/análise , Poluentes do Solo/análise , Monitoramento AmbientalRESUMO
We report extended ethanol-induced gelation procedures of bovine serum albumin (BSA) at 37 °C and investigate the release behavior of a spin-labeled naproxen derivative (SL-NPX) from these hydrogels. The macroscopic mechanical properties of these gels during formation were studied using rheology, while a nanoscopic, more molecular view was obtained by analyzing the secondary structure of the protein during gelation via infrared (ATR-IR) spectroscopy. To evaluate the potential use of BSA hydrogels in controlled drug delivery, SL-NPX-BSA interaction was investigated in detail by continuous-wave electron paramagnetic resonance (CW EPR) spectroscopy, which provides information on the interaction of the small drug molecules and the hydrogel. In addition to CW EPR spectroscopy, dynamic light scattering (DLS), which provides insight into the size and nature of released components, was applied to characterize the combined influence of incubation time, ethanol, SL-drug, and BSA concentration on release behavior. It was found that the alteration of initial drug loading percentage, hydrogel incubation time as well as BSA and alcohol concentrations affect and thus tune the release rate of SL-NPX from BSA hydrogels. These results lead to the conclusion that BSA hydrogels as controlled release systems offer a remarkable fine-tuning capability for pharmaceutical applications due to the variety of gelation parameters.
Assuntos
Naproxeno , Soroalbumina Bovina , Etanol , Hidrogéis/química , Reologia , Soroalbumina Bovina/químicaRESUMO
Co-pyrolysis of coal and seaweed can not only effectively decrease the carbon footprint but also improve the quality and output of coal pyrolysis products, however, the influence of seaweed on thermal releasing behaviors of mercury during co-pyrolysis process are still unclear. In this work, the chlorella and Guizhou bituminous coal were mixed and used to reveal the mercury release behavior during co-pyrolysis by the temperature programmed pyrolysis experiments, thermogravimetric and differential thermogravimetric analysis (TG-DTG) and thermogravimetry-mass spectrometry (TG-MS) methods, offering a sufficient explanation on the control technology of mercury pollutants in co-pyrolysis. The results exhibited that a large amount of reducing gases such as CO, H2 and H2O were generated in chlorella at the temperature range of 100-500°C, which was favorable for the transformation from oxidized mercury to elemental mercury, thus remarkably increased the release of elemental mercury in the raw coal sample. The mixed chlorella also significantly lowered the decomposition temperature range (from 400-600 to 300-400°C) of pyrite-bound mercury and decreased the decomposition temperatures of the pyrite-bound mercury species. Additionally, in the co-pyrolysis about 91.82% of mercury was released into the gas phase below 400°C and was 13.77% higher than that of in individual pyrolysis of coal.
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Chlorella , Mercúrio , Carvão Mineral/análise , Gases , Cinética , Pirólise , TermogravimetriaRESUMO
Incidental capture of sharks during commercial and recreational fishing is of major conservation concern because of the potential effects it can have on physiological stress responses and survival. Endocrine aspects of the stress response are, however, poorly understood in elasmobranchs because of difficulties in measuring the primary glucocorticoid (1α-hydroxycorticosterone). Here, we combined measures of plasma adrenocorticotropic hormone (ACTH), the highly conserved pituitary hormone responsible for stimulating the release of adrenal/interrenal glucocorticoids, with measures of plasma lactate, osmolality, hematocrit, and behavior to gain a greater understanding of the capture stress response in Atlantic Sharpnose sharks, Rhizoprionodon terraenovae. Individuals were subject to a non-repeated measures blood sampling protocol in which blood samples were obtained following exposure to capture stress for <3 min (designated baseline), and 15, 30, 45 and 60 min, after which behavior was categorized during release. Results revealed that ACTH was significantly higher at 15, 30, 45, and 60 min than at baseline. Lactate levels were highest at 45 and 60 min whereas osmolality and hematocrit did not differ significantly among the sampling periods. Lactate was the only variable to significantly predict the shark's behavior upon release with higher lactate levels correlating with sluggish behavior. Measurements of stress indicators are important in understanding the effects of capture on shark populations, which has been implicated in population declines.
Assuntos
Hormônio Adrenocorticotrópico/sangue , Ácido Láctico/sangue , Restrição Física/efeitos adversos , Estresse Fisiológico , Animais , Hematócrito , Concentração Osmolar , TubarõesRESUMO
In recent years, wormwood has been successfully applied in various fields, such as flavouring agent, plant dye, insect repellent and medical product. Wormwood oil encapsulated microcapsules with continuous release behaviours would be further applied in the health care textiles. Here, wormwood oil encapsulated microcapsules with different core-wall materials ratios (gelatine: gum arabic: wormwood oil = 1:1:1, 1:1:2, 1:1:3, 1:1:4) were fabricated. The morphology and physicochemical properties of microcapsules were explored by scanning electron microscopy, ultrasonic wave particle size analysis, thermo gravimetric analysis and so on. The size analysis results indicated that the microcapsule diameter could be controlled less than 1 um. In vitro testing showed that the microcapsules were capable of extending the releasing period to over 6 days. The thermo gravimetric analysis proved that microcapsules had superior thermal stability compared with pure wormwood oil, showing broad application prospects in functional health care textile.
Assuntos
Artemisia/química , Cápsulas/química , Óleos de Plantas/química , Preparações de Ação Retardada , Estabilidade de Medicamentos , Tamanho da Partícula , Têxteis , TermogravimetriaRESUMO
Recently, the potential of nanoparticles (NPs) in ulcerative colitis (UC) therapy has been increasingly demonstrated. Namely, anionic NPs have been found to be accumulated efficiently to the UC damaged area due to epithelial enhanced permeability and retention (eEPR) effect. Previously, a novel anionic nanogel system (NG(S)) was prepared, and evaluated for the efficacy and toxicity. In the present study, release behaviors and biodistribution were investigated in detail to elucidate the functional mechanisms. Rats with 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced ulcerative colitis (UC) were used as biomodels. In vitro release was examined with or without the contents of the cecum or distal colon. Gastrointestinal distribution and plasma concentrations were investigated after the intragastric administration of 10 mg prednisolone (PD) eq./kg. At pH 1.2 and 6.8, release behaviors were slow, but controlled. Overall release was not markedly different irrespective of coexistence of intestinal contents. In in vivo studies, a large amount of PD was distributed in the lower parts of the gastrointestinal tract 6 and 12 h after administration with NG(S). PD accumulated well in the colonic parts, and prolonged release was noted. The systemic absorption of PD with NG(S) was hardly found. NG(S) concentrated the drug in the colon and showed controlled release. These behaviors were considered to lead to the previously reported good results, promotion of effectiveness and suppression of toxic side effects.
Assuntos
Anti-Inflamatórios/administração & dosagem , Quitosana/química , Sistemas de Liberação de Medicamentos , Géis/química , Prednisolona/administração & dosagem , Animais , Anti-Inflamatórios/farmacocinética , Colite Ulcerativa/tratamento farmacológico , Portadores de Fármacos/química , Absorção Gastrointestinal , Trato Gastrointestinal/metabolismo , Masculino , Prednisolona/farmacocinética , Ratos Wistar , Ácido Succínico/químicaRESUMO
BACKGROUND: Spray-dried docosahexaenoic acid algae oil (DHA AO) microcapsules were prepared using whey protein isolate and glucose syrup (WPI + GS), or sodium starch octenylsuccinate and glucose syrup (SSOS + GS), or whey protein isolate and lactose (WPI + L). The effect of the formulations on encapsulation properties, oxidative protection and in vitro oil release pattern of the resulting microencapsulates was investigated. RESULTS: A high encapsulation efficiency of over 98% of DHA AO was obtained for microcapsules with all three wall materials. Among the wall materials, SSOS + GS exhibited a better micro-particulation ability reflected by more uniform size and smoother surface of the formed microcapsules and no agglomerates. DHA AO microcapsules with all the wall materials showed good protection of the oil from oxidation during storage with an increasing order of WPI + GS, SSOS + GS and WPI + L. Moreover, microencapsulation significantly increased the release of DHA AO in the intestinal phase of the in vitro digestion process with an increasing order of SSOS + GS, WPI + GS and WPI + L, indicating the increased stability of the oil in the highly acidic gastric environment and the enhanced lipid digestibility in the small intestine. CONCLUSIONS: The results suggest that it is possible to transform a highly oxidizable liquid functional food ingredient such as DHA AO into a stable and easy-to-handle solid powder through spray drying with properly selected wall materials. © 2020 Society of Chemical Industry.
Assuntos
Cápsulas/química , Ácidos Docosa-Hexaenoicos/química , Oxirredução , Óleos de Plantas/química , Dessecação/métodos , Digestão , Armazenamento de Alimentos , Alimento Funcional , Glucose/química , Lactose/química , Amido/química , Proteínas do Soro do LeiteRESUMO
With an increased awareness of the link between the consumption of omega 3-6-9 fatty acid-rich oils and health, the food industry has been developing innovative strategies for raising their levels within the diet. Microencapsulation is one approach used to protect those oils from oxidative deterioration and to improve their ingredient properties (e.g., handling and sensory). Spray drying is the most commonly used technique to develop microcapsules. The preparation of protein-stabilized emulsions is a fundamental step in the process in order to produce microcapsules with good physical properties, effective protection and controlled release behaviors. This review describes types of emulsions prepared by animal and plant proteins, discusses the relationship between emulsion properties and microcapsule properties, and identifies key parameters to evaluate physical properties (e.g., moisture content, water activity, particle size, surface oil and entrapment efficiency), oxidative stability and release behavior of spray-dried microcapsules for industrial application.
RESUMO
The ability to control drug loading and release is the most important feature in the development of medical devices. In this research, we prepared a functional nanocoating technology to incorporate a drug-release layer onto a desired substrate. The multilayer films were prepared using chitosan (CHI) and carboxymethyl cellulose (CMC) polysaccharides by the layer-by-layer (LbL) method. By using chemical cross-linking to change the inner structure of the assembled multilayer, we could control the extent of drug loading and release. The cross-linked multilayer film had a porous structure and enhanced water wettability. Interestingly, more of the small-molecule drug was loaded into and released from the non-cross-linked multilayer film, whereas more of the macromolecular drug was loaded into and released from the cross-linked multilayer film. These results indicate that drug loading and release can be easily controlled according to the molecular weight of the desired drug by changing the structure of the film.
Assuntos
Carboximetilcelulose Sódica/química , Quitosana/química , Liberação Controlada de Fármacos , Nanoestruturas/química , Química Farmacêutica , Reagentes de Ligações Cruzadas/química , Porosidade , Propriedades de Superfície , MolhabilidadeRESUMO
Actually, reflecting drug release from polymer-coated pellets remains a challenge. In this study, sticking of pellets caused by Eudragit®L30D-55 was observed during the release process, leading to change in drug release. Talcum powder (talc) was used in esomeprazole magnesium pellets to prevent sticking and modify release of pellets. Three methods including talc incorporated in enteric layer, physically mixed and coating resulted pellets were employed to prevent the sticking. The release of pellets was modified by addition talc into subcoat. The dispersion coefficient (Fd) and release profiles were determined in phosphate buffer solution (pH 6.8 and 6.0) and distilled water. It was found that the first manner made Fd increase to about 0.75, but the latter two methods could completely prevent sticking. Also, the second manner was more simple and readily scaled up. In addition, talc in subcoat significantly slowed the drug release in water, but the slowing release effect is less pronounced at pH 6.0 and 6.8. These different effects of talc were attributed to a different release mechanism in three media. The release profiles in water were fitted to Nuttanan model, and the K designated as "diffusive resistance constant" was linearly increased with talc levels in subcoat (R(2)=0.9874).
Assuntos
Antiulcerosos/administração & dosagem , Esomeprazol/administração & dosagem , Excipientes/química , Ácidos Polimetacrílicos/química , Comprimidos com Revestimento Entérico/química , Talco/química , Antiulcerosos/química , Liberação Controlada de Fármacos , Esomeprazol/química , Solubilidade , Água/químicaRESUMO
Local intra-pocket drug delivery devices can provide an effective concentration of the antimicrobial agent at the site of action with avoidance of undesirable side effects. This study explored the application of chitosan-alginate and chitosan-pectin polyelectrolyte complex (PEC) films as drug release regulators for tetracycline HCl (Tc) to treat periodontal pockets. Periodontal films with 1:1 Tc:PEC ratio were prepared using 1:1 chitosan (Ch) to sodium alginate (A) or 1:3 Ch to pectin (P). The scanning electron microscope showed acceptable film appearance and differential scanning calorimetry analysis confirmed complex formation. The in vitro release studies for both films showed a burst drug release, followed by prolonged release for 70 h. A prolonged antibacterial activity of both films against Staphylococcus aureus ATCC 6538 was observed over a period of 21 days. Aging studies indicated that the five months storage period in freezer did not significantly influence the drug release profile or the antibacterial activity of both films. Clinical evaluation showed a significant reduction in pocket depth (p < 0.0001) to their normal values (≤3 mm). PEC films could be exploited as a prolonged drug release devices for treatment of periodontal pockets.
Assuntos
Antibacterianos/administração & dosagem , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Tetraciclina/administração & dosagem , Alginatos/química , Antibacterianos/farmacologia , Varredura Diferencial de Calorimetria , Química Farmacêutica/métodos , Quitosana/química , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Eletrólitos/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Humanos , Pectinas/química , Staphylococcus aureus/efeitos dos fármacos , Tetraciclina/farmacologia , Fatores de TempoRESUMO
Coacervation, a common method for microspheres preparation, has not been given sufficient attention and study. This study aims to clarify the key factors in the phase separation step. Firstly, based on the thermodynamics of polymer solutions, the phase equilibrium time, binodal line, and the relationship between the concentration of lactic-glycolic acid copolymer (PLGA) in the coacervate phase (CPLGA) and the concentration of polydimethylsiloxane (PDMS) in the PLGA-lean phase (CPDMS) were determined. It was found that the lactic:glycolic ratio (L:G) significantly influences phase separation, and we introduced a method to calculate the compositions and masses of both the coacervate and PLGA-lean phases after phase separation of a system composed of PLGA, PDMS, and dichloromethane (DCM). Furthermore, some impellers aimed at producing narrow size distribution microspheres were designed, and the stirring states were analyzed visually using Computational Fluid Dynamics (CFD), explaining the impact of impeller types and clearance between impeller and vessel on particle size distribution. Measurements of the viscosities of the coacervate and continuous phases, coupled with emulsion theories, clarified the behavior of emulsion during the phase separation step, while also highlighting that the key to preparing narrow size distribution microspheres lies in weakening the coalescence of coacervate droplets. Finally, in vitro release demonstrated that CPLGA and the particle size distribution of coacervate droplets are key factors in the phase separation step.
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Self-assembled protein fibers have attracted much attention in the fields of medicine and food because of their high aspect ratio, polymorphic structure and strong surface hydrophobicity. In this study, three different gelation types of polysaccharides/ß-lactoglobulin fiber (Fblg) composite gels, including ionic alginate-Fblg gels, synergistic xanthan-Fblg gels, and double network agar-Fblg gels, were first prepared. The interactions between the polysaccharides and the Fblgs, the microstructure and mechanical properties of the composite gels were investigated using the light scattering, scanning electron microscopy, rheology and texture analysis in order to reveal their formation mechanisms. Then the loading and release properties of the water-soluble drug 5-fluorouracil (5-FU) and the hydrophobic drug curcumin (Cur) through these composite gels were further studied with release mechanisms determined by fitting different release models. It was found that the mechanical properties of the composite gels were determined by the mesh density of the three-dimensional networks formed inside the gels. The network structure and mechanical strength of the alginate-Fblg gels became weaker with the increase of Fblg content at pH 4 due to their attractive interaction which hindered the binding of Ca2+ to ALG, while the network and the strength of the alginate-Fblg gels didn't change much at pH 7 due to the repulsion between Alg and Fblg. The xanthan-Fblg gels formed lamellar structures with enhanced gel network and mechanical strength due to the hydrogen bonding and the electrostatic interaction with Fblg. The Agar-Fblg composite gel formed at 60 °C (above the gelation temperature of agar of 40 °C) had a denser double network structure and higher mechanical strength than that formed at 0 °C due to inhibition of diffusion of Ca2+ as salt bridges for Fblg. The hydrophilic drugs were loaded in the meshes of the composite gels and their release was determined by the structure of the composite gel networks, whereas the hydrophobic drugs were loaded by attaching to the Fblgs in the composite gels and their release was determined by the loading ability and strength of the gels. The study not only provided a new idea for the preparation and application of polysaccharide-protein fiber composite hydrogels, but also provided insights for improving the efficiency of drug carriers.
Assuntos
Liberação Controlada de Fármacos , Géis , Lactoglobulinas , Polissacarídeos , Lactoglobulinas/química , Géis/química , Polissacarídeos/química , Reologia , Alginatos/química , Portadores de Fármacos/química , Fluoruracila/química , Curcumina/química , Concentração de Íons de Hidrogênio , Polissacarídeos Bacterianos/química , Interações Hidrofóbicas e HidrofílicasRESUMO
GFP1, a sulfated polysaccharide extracted from Grateloupia filicina, exhibits remarkable immunomodulatory activity. To reduce the side effects of 5-fluorouracil (5-FU), GFP1 was employed as a macromolecular carrier to synthesize of GFP1-C-5-FU by reacting with carboxymethyl-5-fluorouracil (C-5-FU). Subsequently, this new compound was reacted with folic acid (FA) through an ester bond, forming novel conjugates named GFP1-C-5-FU-FA. Nuclear magnetic resonance analysis confirmed the formation of GFP1-C-5-FU-FA. In vitro drug release studies revealed that the cumulative release rate of C-5-FU reached 46.9 % in phosphate buffer (pH 7.4) after 96 h, a rate significantly higher than that of the control groups, indicating the controlled drug release behavior of GFP1-C-5-FU-FA. Additionally, in vitro anticancer assays demonstrated the potent anticancer activity of GFP1-C-5-FU-FA conjugates, as evidenced by the reduced viability of HeLa and AGS cancer cells, along with increased levels of apoptosis and cellular uptake. Western blot analysis indicated that the GFP1-C-5-FU-FA conjugate effectively enhanced phosphorylation in cancer cells through the NF-kB and MAPK pathways, thereby promoting apoptosis. These findings highlight the potential of folate-targeted conjugates in efficiently treating HeLa and AGS cancer cells in vitro and lay a robust theoretical groundwork for future in vivo anti-cancer research involving these cells.
Assuntos
Antineoplásicos , Fluoruracila , Ácido Fólico , Polissacarídeos , Fluoruracila/farmacologia , Fluoruracila/química , Humanos , Ácido Fólico/química , Ácido Fólico/farmacologia , Polissacarídeos/química , Polissacarídeos/farmacologia , Antineoplásicos/farmacologia , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Sulfatos/química , Células HeLa , Liberação Controlada de Fármacos , Sistemas de Liberação de Medicamentos , Portadores de Fármacos/química , Sobrevivência Celular/efeitos dos fármacosRESUMO
Captopril (CTP) is an oral drug widely used to treat high blood pressure and congestive heart failure. In this study, CTP-incorporated biomaterials for antihypertensive therapy were synthesized from chitosan, carboxymethyl cellulose, and plasticizers. The physicochemical properties of the prepared biomaterials were characterized using FE-SEM, FT-IR analysis, and physical properties. CTP release experiments were carried out in buffer solutions at various pH values and temperatures. Results indicated that above 99.0 % of CTP was released within 180 min. Optimization of the experimental conditions for CTP release was analyzed by using response surface methodology (RSM). Results of CTP release through artificial skin indicated that CTP was continuously released above 95.0 % from the prepared biomaterials for 36.0 h. The CTP release mechanisms into a buffer and through artificial skin followed pseudo-Fickian diffusion mechanism and non-Fickian diffusion mechanisms, respectively. Moreover, angiotensin-converting enzyme (ACE) inhibition (related to cardiovascular disease) via the released CTP clearly reveals that the prepared biomaterials have a high potential as a transdermal drug delivery agent in antihypertensive therapy.
Assuntos
Captopril , Quitosana , Captopril/química , Captopril/uso terapêutico , Anti-Hipertensivos/química , Quitosana/química , Carboximetilcelulose Sódica/química , Liberação Controlada de Fármacos , Materiais Biocompatíveis , Espectroscopia de Infravermelho com Transformada de Fourier , Portadores de Fármacos/químicaRESUMO
We revealed that the encapsulation of enzyme-immobilized silica particles in hollow-type spherical bacterial cellulose (HSBC) gels enables the use of the inside of HSBC gels as a reaction field. The encapsulation of horseradish peroxidase (HRP)-immobilized silica particles (Si-HRPs, particle size: 40-50 µm) within HSBC gels was performed by using a BC gelatinous membrane produced at the interface between Komagataeibacter xylinus suspension attached onto an alginate gel containing Si-HRPs and silicone oil. After the biosynthesis of the BC gelatinous membrane, formed from cellulose nanofiber networks, the alginate gel was removed via immersion in a phosphate-buffered solution. Si-HRP encapsulated HSBC gels were reproducibly produced using our method with a yield of over 90%. The pore size of the network structure of the BC gelatinous membrane was less than 1 µm, which is significantly smaller than the encapsulated Si-HRPs. Consequently, the encapsulated Si-HRPs could neither pass through the BC gelatinous membrane nor leak from the interior cavity of the HSBC gel. The activity of the encapsulated HRPs was detected using the 3,3',5,5'-tetramethylbenzidine (TMB)-H2O2 system, demonstrating that this method can encapsulate the enzyme without inactivation. Since HSBC gels are composed of a network structure of biocompatible cellulose nanofibers, immune cells cannot enter the hollow interior, thus, the enzyme-immobilized particles encapsulated inside the HSBC gel are protected from immune-cell attacks. The encapsulation technique demonstrated in this study is expected to facilitate the delivery of enzymes and catalysts that are not originally present in the in vivo environment.
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Heavy metals raise a global concern and can be easily retained by ubiquitous iron (oxyhydr)oxides in natural and engineered systems. The complex interaction between iron (oxyhydr)oxides and heavy metals results in various mineral-metal binding configurations, such as outer-sphere complexes and edge-sharing inner-sphere complexes, which determine the accumulation and release of heavy metals in the environment. However, traditional experimental approaches are time-consuming and inadequate to elucidate the complex binding relationships and configurations between iron (oxyhydr)oxides and heavy metals. Herein, a workflow that integrates the binding configuration data of 11 heavy metals on 7 iron (oxyhydr)oxides and then trains machine learning models to predict unknown binding configurations was proposed. The well-trained multi-grained cascade forest models exhibited high accuracy (> 90%) and predictive performance (R2 â¼ 0.75). The underlying effects of mineral properties, metal ion species, and environmental conditions on mineral-metal binding configurations were fully interpreted with data mining. Moreover, the metal release rate was further successfully predicted based on mineral-metal binding configurations. This work provides a method to accurately and quickly predict the binding configuration of heavy metals on iron (oxyhydr)oxides, which would provide guidance for estimating the potential release behavior of heavy metals and remediating heavy metal pollution in natural and engineered environments.
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Nanoparticles are used as fillers to improve the properties of biopolymers, and their particle size is an important parameter. This work aims to investigate the effect of particle size of isoreticular metal-organic framework-3 (IRMOF-3) on the mechanical, physical, and release properties of sodium alginate (SA)-based composite active film. In our study, IRMOF-3 with six different particle sizes was synthesized by introducing additives. IRMOF-3 loading with carvacrol (IRMOF-3/CA nanoparticles) was incorporated into the SA matrix to prepare the composite film. The characterization and testing results of films showed that the particle size of nanoparticles affected the physical morphology and chemical structure of the film. Especially smaller nanoparticles uniformly dispersed into the SA matrix more easily, forming a denser and more stable spatial network structure with SA, which could more significantly improve the tensile strength, water vapor barrier, and hydrophobic properties of the film (P < 0.05). In addition, the CA release rate from the active film could be significantly reduced by about 33.90 % even when the smallest particle size of the IRMOF-3/CA nanoparticles was added. Therefore, when IRMOF-3/CA is used as the nano-filler to develop SA-based active film, its particle size has a potential influence on the properties of the film.