Ultrasound stimulated release of mimosa medicine from cellulose hydrogel matrix

Ultrasound (US) drug release system using cellulose based hydrogel films was developed as triggered to mimosa. Here, the mimosa, a fascinating drug to cure injured skin, was employed as the loading drug in cellulose hydrogel films prepared with phase inversion method. The mimosa hydrogels were fabricated from dimethylacetamide (DMAc)/LiCl solution in the presence of mimosa, when the solution was exposed to ethanol vapor. The US triggered release of the mimosa from the hydrogel matrix was carried out under following conditions of US powers (0–30 W) and frequencies (23, 43 and 96 kHz) for different mimosa hydrogel matrix from 0.5 wt% to 2 wt% cellulose solution. To release the drug by US trigger from the matrix, the better medicine release was observed in the matrix prepared from the 0.5 wt% cellulose solution when the 43 kHz US was exposed to the aqueous solution with the hydrogel matrix. The release efficiency increased with the increase of the US power from 5 to 30 W at 43 kHz. Viscoelasticity of the hydrogel matrix showed that the hydrogel became somewhat rigid after the US exposure. FT-IR analysis of the mimosa hydrogel matrixes showed that during the US exposure, hydrogen bonds in the structure of mimosa–water and mimosa–cellulose were broken. This suggested that the enhancement of the mimosa release was caused by the US exposure.     

A single step ultrasound-assisted nitrocellulose synthesis from microcrystalline cellulose

Nitrocellulose is a nitrated cellulose polymer with a broad application in industry. Depending on the nitrogen content, this polymer can be used for manufacturing explosives, varnishes, clothes, and films, being considered a product of high value-added. In this work, the use of ultrasound was investigated for the intensification of nitrocellulose synthesis from microcrystalline cellulose. The ultrasound-assisted nitrocellulose synthesis (UANS) was carried out using several ultrasound systems, such as baths and cup horns, allowing the evaluation of the frequency (from 20 to 130 kHz) and delivered power (from 23 to 134 W dm⁻³) to the reaction medium. The following parameters were evaluated: acid mixture (H₂SO₄, H₃PO₄, CH₂O₂ or CH₃COOH with HNO₃, 2 to 14.4 mol L⁻¹), ultrasound amplitude (10 to 70%) and reaction time (5 to 50 min). Better nitrocellulose yield (nitrogen content of 12.5% was obtained from 1 g of microcrystalline cellulose employing a cup horn system operating at 20 kHz, 750 W of nominal power with 60% of amplitude, 25 mL of acid solution (13.6 mL of 18.4 mol L⁻¹ H₂SO₄ + 9.2 mL of 14.4 mol L⁻¹ HNO₃ + 2.2 mL H₂O), at 30 °C for 30 min. At silent conditions (mechanical stirring ranging from 100 to 500 rpm), the nitrogen content was lower than 11.8% which demonstrate the ultrasound effects for nitrocellulose synthesis.     

Synthesis of cellulose nanocrystals (CNCs) from cotton using ultrasound-assisted acid hydrolysis

This present work reports the synthesis of Cellulose nanocrystals (CNCs) from cotton using an ultrasound-assisted acid hydrolysis. Further, the synthesized CNCs was comprehensively characterized using Fourier Transform Infrared Spectroscopy (FTIR) to analyze surface functional groups and X-ray diffraction (XRD) in studying structural characteristics. Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) have been used to study the thermal properties of CNCs. Morphology of CNCs was studied using a Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM). The crystallite size was found to be 10–50 nm using XRD data and the average particle size to be 221 nm using PSD analysis.     

Ultrasound-assisted dyeing of cellulose acetate

The possibility of reducing the use of auxiliaries in conventional cellulose acetate dyeing with Disperse Red 50 using ultrasound technique was studied as an alternative to the standard procedure. Dyeing of cellulose acetate yarn was carried out by using either mechanical agitation alone, with and without auxiliaries, or coupling mechanical and ultrasound agitation in the bath where the temperature range was maintained between 60 and 80 °C.The best results of dyeing kinetics were obtained with ultrasound coupled with mechanical agitation without auxiliaries (90% of bath exhaustion value at 80 °C). Hence the corresponding half dyeing times, absorption rate constants according to Cegarra–Puente modified equation and ultrasound efficiency were calculated confirming the synergic effect of sonication on the dyeing kinetics. Moreover the apparent activation energies were also evaluated and the positive effect of ultrasound added to mechanical agitation was evidenced by the lower value (48 kJ/mol) in comparison with 112 and 169 kJ/mol for mechanical stirring alone with auxiliaries and without, respectively.Finally, the fastness tests gave good values for samples dyed with ultrasound technique even without auxiliaries. Moreover color measurements on dyed yarns showed that the color yield obtained by ultrasound-assisted dyeing at 80 °C of cellulose acetate without using additional chemicals into the dye bath reached the same value yielded by mechanical agitation, but with remarkably shorter time.     

Effects of ultrasonic conditions on the interfacial property and emulsifying property of cellulose nanoparticles from ginkgo seed shells

Cellulose microparticles from ginkgo seed shells were treated by ultrasonic treatments within the selected output powders (150–600 W) and durations (10–60 min) to produce cellulose nanoparticles. The main aim of this study was to investigate effects of ultrasonic conditions on the interfacial property and emulsifying property of those cellulose nanoparticles. Compared to ultrasonic output powers, ultrasonic durations showed the greater influence on morphology and physical properties of cellulose nanoparticles. Atomic force microscopy revealed that noodle-like cellulose particles with 1100 nm in length gradually became the short rod-like nanoparticles with 300 nm in length with increasing of ultrasonic duration from 10 min to 60 min. Moreover, results of contact angles indicated that ultrasound could significantly improve hydrophobicity of cellulose nanoparticles. The interfacial shear rheology showed that although all cellulose nanoparticles exhibited the similar interface adsorption behavior which showed the initial lag-phase of adsorption, followed by the interface saturation, the time of this initial lag-phase was affected by ultrasonic conditions. The increase of ultrasonic duration and ultrasonic power could shorten the time of this initial lag-phase, suggesting the resulting cellulose nanoparticles easier adsorption at the O/W interface. It was probably attributed to its small size and high hydrophobicity induced by intense ultrasonic treatments. Meanwhile, the cellulose nanoparticles with small size and higher hydrophobicity exhibited the better emulsifying ability to stabilize oil-in-water emulsions due to the formation of the viscoelastic interfacial film. This study improved understanding about changes in interfacial and emulsifying properties of cellulose nanoparticles caused by ultrasonic treatments.     

Influence of ultrasound treatment on accessibility and regioselective oxidation reactivity of cellulose

Cellulose fibers were treated with ultrasound in order to improve the accessibility and the reactivity of cellulose. The influence of ultrasound treatment on changes of morphology structure, accessibility and oxidation reactivity of cellulose with sodium periodate were discussed. The results revealed an increase in cellulose’s accessibility in terms of water retention value (WRV) with increasing ultrasound treatment time, corresponding to 73.0%, 75.6%, 80.8%, 98.7% and 119.0% after treated for 0, 90, 180, 360 and 720 s, respectively. Furthermore, the regioselective oxidation reactivity of cellulose with sodium periodate was also successfully improved by the ultrasound treatment. However, no significant changes in crystallinity of cellulose were noted after ultrasound treatment. The oxidized products dialdehyde cellulose (DAC) was further characterized by means of FTIR, X-ray diffraction and SEM.     

Ultrasound response of viscoelastic changes of cellulose hydrogels triggered with Sono-deviced rheometer

Sono-deviced rheometer,which enabled viscoelastic properties under ultrasound operation, was used to investigate for cellulosic hydrogels. The viscoelastic behavior was compared in cellulosic hydrogels prepared at 0.5, 1 and 2 wt% concentration in the DMAc/LiCl solution. The sono-deviced equipment could measure the effect of changes in storage modulus G’ and loss modulus G” under 43 kHz ultrasound exposure. It was noted that the 43 kHz ultrasound significantly changed the values of the G′, meaning that the hydrogel was soften under the exposure within few seconds. When the ultrasound exposed 50 W of the out-put power at 1% strain, the G′ value of 4.2x10⁴ Pa was reduced to 4.0x10³ Pa during 5 min of the US interval. The declined lowering value of G’ then returned to the original moduli value when ultrasound was stopped. The values of both G’ and G” values were measured at applied strain % during viscoelastic measurements of the cellulosic hydrogels without and with ultrasound exposure. The comparison indicated that the ultrasound has reinforced the effect of the mechanical deformation of the hydrogel structure at the smaller mechanical strain values applied during the ultrasound operation. The ultrasound soften effect on the viscoelastic change efficiently occurred in the 0.5 wt% sample and easily induced the structural deformation probably due to the breakage of hydrogen bonds in the cellulose hydrogels.     

Comparison of two different ultrasound reactors for the treatment of cellulose fibers

The pulp and paper industry is in continuous need for energy-efficient production processes. In the refining process of mechanical pulp, fibrillation is one of the essential unit operations that count for up to 80% of the total energy use. This initial study explores the potential and development of new type of scalable ultrasound reactor for energy efficient mechanical pulping. The developed reactor is of continuous flow type and based on both hydrodynamic and acoustic cavitation in order to modify the mechanical properties of cellulose fibers. A comparison of the prototype tube reactor is made with a batch reactor type where the ultrasonic horn is inserted in the fluid. The pulp samples were sonicated by high-intensity ultrasound, using tuned sonotrodes enhancing the sound pressure and cavitation intensity by a controlled resonance in the contained fluid. The resonant frequency of the batch reactor is 20.8 kHz and for the tube reactor it is 22.8 kHz. The power conversion efficiency for the beaker setup is 25% and 36% in case of the tube reactor in stationary mode. The objective is to verify the benefit of resonance enhanced cavitation intensity when avoiding the effect of Bjerkenes forces. The setup used enables to keep the fibers in the pressure antinodes of the contained fluid. In case of the continuous flow reactor the effect of hydrodynamic cavitation is also induced. The intensity of the ultrasound in both reactors was found to be high enough to produce cavitation in the fluid suspension to enhance the fiber wall treatment. Results show that the mechanical properties of the fibers were changed by the sonification in all tests. The continuous flow type was approximately 50% more efficient than the beaker. The effect of keeping fibers in the antinode of the resonant mode shape of the irradiation frequency was also significant. The effect on fiber properties for the tested mass fraction was determined by a low-intensity ultrasound pulse-echo based measurement method, and by a standard pulp analyzer.     

High-intensity ultrasound-assisted formation of cellulose nanofiber scaffold with low and high lignin content and their cytocompatibility with gingival fibroblast cells

Cellulose nanofiber (CNF) hydrogels with low lignin (8%) (LL-CNF) and high lignin (18%) (HL-CNF) content were produced at nominal powers of 240, 720 and 1200 W using high-intensity ultrasound technology (HIUS). Freeze-dried CNF hydrogels were evaluated as scaffolds for gingival fibroblast cells proliferation aiming biomedical applications. HIUS processing improved the dispersibility of the CNF and increased the water retention value by more than 5 times. The LL-CNF had a maximum fibrillation yield of 46 wt.%, whereas the HL-CNF had a maximum fibrillation yield of 40 wt.% at nominal power of ≥720 W. Regardless of the lignin content, the CNF hydrogels exhibited a typical elastic gel-like behavior with the highest elasticity of 263 Pa. After freeze-drying, the CNF aerogels had porosity ≥ 96.8%, and swelling capacity up to 42.1 g PBS/g aerogel. Moreover, the cell proliferation assay showed no differences in proliferation among the LL-CNF and HL-CNF scaffolds up to 11 days. Therefore, CNF scaffolds prepared with lignin content up to 18% present promising application in the biomedical field.     

A study of the kinetics of isothermal nicotine desorption from silicon dioxide

The isothermal kinetics of nicotine desorption from silicon dioxide (SiO₂) was investigated. The isothermal thermogravimetric curves of nicotine at temperatures of 115 °C, 130 °C and 152 °C were recorded. The kinetic parameters (E_a, ln A) of desorption of nicotine were calculated using various methods (stationary point, model constants and differential isoconversion method). By applying the “model-fitting” method, it was found that the kinetic model of nicotine desorption from silicon dioxide was a phase boundary controlled reaction (contracting volume). The values of the kinetic parameters, E_a,α and ln A_α, complexly change with changing degree of desorption and a compensation effect exists. A new mechanism of activation for the desorption of the absorbed molecules of nicotine was suggested in agreement with model of selective energy transfer.     

新型自动化细胞涂片和激光释放系统用于近红外光响应释放有核红细胞北大核心CSCD

为了实现外周血有核红细胞的分离与释放,开发安全有效的非侵入式技术分离有核红细胞以用于产前胎儿疾病诊断,本文以水凝胶材料为基底建立自动化细胞涂片制备系统,并构建用于识别释放有核红细胞的激光会聚和显微成像系统。首先,设计了细胞涂片制备机的机械结构,基于单片机制作上位机控制软件,优化推片角度和速度参数制备水凝胶膜基底涂片,在温敏水凝胶明胶中引入二维材料MXene,结合MXene的近红外光热转换特性,在水凝胶膜表面实现近红外光响应。然后,在水凝胶基底膜表面进行全血推片实验,优化血液推片参数,制备得到单层细胞涂片。最后,建立激光会聚和显微成像光路,对有核红细胞进行识别定位。808 nm激光器的光源经过准直镜和会聚镜聚焦到细胞涂片表面,产生光热效应进行细胞释放。此项工作实现了单层细胞涂片的加工制备,在808 nm近红外光下产生光热效应,经过激光会聚系统的调控,最终得到了光斑直径为300μm的细胞定点释放区域。本文将自动推片技术应用于以水凝胶膜为基底的单层细胞涂片的制备,建立激光会聚与显微成像光路,通过水凝胶膜的近红外响应以及热响应特性,实现了有核红细胞的识别与定点释放,提高了有核红细胞分离富集效率,在产前筛选诊断领域中具备广阔的应用前景。     

Incorporation and release of drug into/from superparamagnetic iron oxide nanoparticles

The aim of this study was to attach a model drug (naproxen) onto superparamagnetic iron oxide nanoparticles (SPION). First, SPION were coated with thin layer of silica that contained micropores. We demonstrated that such surface functionalization could be optimized by the use of citric acid which prevented SPION agglomeration during the procedure. HRTEM investigation showed a uniform 1-2-nm-thick silica coating around SPION. This coating did not affect significantly the magnetic properties of the SPION. Into the coated SPION we successfully incorporated about 30 wt% of naproxen. The latter was readily released after immersion into a testing solution. The composites could be interesting for potential use in diagnostics.     

One injection for one-week controlled release: In vitro and in vivo assessment of ultrasound-triggered drug release from injectable thermoresponsive biocompatible hydrogels

Episodic release of bioactive compounds is often necessary for appropriate biological effects under specific physiological conditions. Here, we aimed to develop an injectable, biocompatible, and thermosensitive hydrogel system for ultrasound (US)-triggered drug release. An mPEG-PLGA-BOX block copolymer hydrogel was synthesized. The viscosity of 15 wt% hydrogel is 0.03 Pa*s at 25 °C (liquid form) and 34.37 Pa*s at 37 °C (gel form). Baseline and US-responsive in vitro release profile of a small molecule (doxorubicin) and that of a large molecule (FITC-dextran), from the hydrogel, was tested. A constant baseline release was observed in vitro for 7 d. When triggered by US (1 MHz, continuous, 0.4 W/cm²), the release rate increased by approximately 70 times. Without US, the release rate returned to baseline. Baseline and US-responsive in vivo release profile of doxorubicin was tested by subcutaneous injection in the back of mice and rats. Following injection into the subcutaneous layer, in vivo results also suggested that the hydrogels remained in situ and provided a steady release for at least 7 d; in the presence of the US-trigger, in vivo release from the hydrogel increased by approximately 10 times. Therefore, the mPEG-PLGA-BOX block copolymer hydrogel may serve as an injectable, biocompatible, and thermosensitive hydrogel system that is applicable for US-triggered drug release.     

Encapsulating doxorubicin-intercalated lamellar nanohydroxyapatite into PLGA nanofibers for sustained drug release

In this work, doxorubicin (DOX) was intercalated into layered nanohydroxyapatite (LHAp). The drug loaded LHAp (DOX@LHAp) was then mixed with poly(lactic-co-glycolic acid) (PLGA) and electrospun to yield DOX@LHAp/PLGA composite scaffolds. As control, needle-like nanohydroxyapatite (nHAp) was also used to make an DOX@nHAp/PLGA composite scaffold and bare DOX was used to fabricate DOX/PLGA scaffold. The morphology, release behavior of DOX, and capability to inhibit cancer cells were assessed. The addition of DOX-loaded nHAp to PLGA causes a slight decrease in the average fiber diameter of DOX@LHAp/PLGA as compared to PLGA. The in vitro drug release tests reveal a much faster release of DOX from DOX/PLGA than DOX@LHAp/PLGA. Moreover, DOX@LHAp/PLGA displays a more sustainable release over DOX@nHAp/PLGA due to the storage of DOX in the gallery of LHAp, which is further proved by their cancer cell inhibition results. We believe that the DOX@LHAp/PLGA scaffold has potential as an implantable drug delivery system.     

Adsorption of nicotine from aqueous solution onto hydrophobic zeolite type USY

The isothermal adsorption of nicotine from an aqueous solution onto zeolite type USY was investigated. The adsorption isotherms of nicotine onto the zeolite at different temperatures ranging from 298 to 322 K were determined. It was found that the adsorption isotherms can be described by the model of Freundlich adsorption isotherm. Based on the adsorption isotherms the changes of adsorption heat, free energy and entropy with adsorption degree were determined. The determined decrease of adsorption heat with adsorption degree can be explained by the presence of the adsorption centers of different energy and concentration on interface of zeolite-nicotine solution. It was found that the probability function of density distribution of the heat of adsorption (DDF) has exponential form. It was concluded that the possibility of fitting the adsorption isotherms of nicotine onto the zeolite by Freundlich adsorption isotherm was a direct consequence of that. The determined increase in entropy with the increase in adsorption degree can be explained with the change of phase state of adsorbed nicotine.     

Acoustic-responsive carbon dioxide-loaded liposomes for efficient drug release

The role of liposomes as drug carriers has been investigated. Ultrasound-based drug release methods have been developed for on-demand drug delivery. However, the acoustic responses of current liposome carriers result in low drug release efficiency. In this study, CO₂-loaded liposomes were synthesized under high pressure from supercritical CO₂ and irradiated with ultrasound at 237 kHz to demonstrate their superior acoustic responsiveness. When liposomes containing fluorescent drug models were irradiated with ultrasound under acoustic pressure conditions that are safe for the human body, CO₂-loaded liposomes synthesized using supercritical CO₂ had 17.1 times higher release efficiency than liposomes synthesized using the conventional Bangham method. In particular, the release efficiency of CO₂-loaded liposomes synthesized using supercritical CO₂ and monoethanolamine was 19.8 times higher than liposomes synthesized using the conventional Bangham method. These findings on the release efficiency of acoustic-responsive liposomes suggest an alternative liposome synthesis strategy for on-demand release of drugs by ultrasound irradiation in future therapies.     

High intensity focused ultrasound responsive release behavior of metallo-supramolecular block PPG-PEG copolymer micelles

An amphiphilic metallo-supramolecular poly(propylene glycol)-block-poly(ethylene glycol) block copolymer containing a bis(2,2′:6′,2″-terpyridine) ruthenium (II) complex as a supramolecular connection between the two constituting blocks was used to prepare stable aqueous micelles which displayed a high intensity focused ultrasound (HIFU) triggered release behavior. By adjusting the HIFU time and intensity, the novel modality of HIFU triggered release allows for fine-tuning of the release kinetics of the encapsulants from the micelles in a remote and controlled way. Nuclear magnetic resonance spectroscopy, ultraviolet spectroscopy, and matrix-assisted laser desorption/ionization-time of flight mass spectrometry confirmed that the degradation of the micelles was due to the cleavage of the ether bond connected to the pyridine ring. This well controlled HIFU-copolymer micelle drug delivery system has considerable potential in targeted therapy.     

Cross-linked gelatin/nanoparticles composite coating on micro-arc oxidation film for corrosion and drug release

A composite coating which could control drug release and biocorrosion of magnesium alloy stent materials WE42 was prepared. This composite coating was fabricated on the surface of the micro-arc oxidation (MAO) film of the magnesium alloy, WE42, by mixing different degrees of cross-linked gelatin with well-dispersed poly(dl-lactide-co-glycolide) (PLGA) nanoparticles. The PLGA nanoparticles were prepared by emulsion solvent evaporation/extraction technique. Nano ZS laser diffraction particle size analyzer detected that the size of the nanoparticles to be 150-300 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) was used to analyze the morphology of the nanoparticles and the composite coating. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion behavior of the composite coating. Drug release was determined by ultraviolet-visible (UV-vis) spectrophotometer. The corrosion resistance of the composite coating was improved by preventing the corrosive ions from diffusing to the MAO films. The drug release rate of paclitaxel (PTX) exhibited a nearly linear sustained-release profile with no significant burst releases.     

Fabrication and characterization of cellulose nanoparticles from maize stalk pith via ultrasonic-mediated cationic etherification

In this study, parenchyma cellulose, which was extracted from maize stalk pith as an abundant source of agricultural residues, was applied for preparing cellulose nanoparticles (CNPs) via an ultrasound-assisted etherification and a subsequent sonication process. The ultrasonic-assisted treatment greatly improved the modification of the pith cellulose with glycidyltrimethylammonium chloride, leading to a partial increase in the dissolubility of the as-obtained product and thus disintegration of sheet-like cellulose into nanoparticles. While the formation of CNPs by ultrasonication was largely dependent on the cellulose consistency in the cationic-modified system. Under the condition of 25% cellulose consistency, the longer sono-treated duration yielded a more stable and dispersible suspension of CNP due to its higher zeta potential. Degree of substitution and FT-IR analyses indicated that quaternary ammonium salts were grafted onto hydroxyl groups of cellulose chain. SEM and TEM images exhibited the CNP to have spherical morphology with an average dimeter from 15 to 55 nm. XRD investigation revealed that CNPs consisted mainly of a crystalline cellulose Ι structure, and they had a lower crystallinity than the starting cellulose. Moreover, thermogravimetric results illustrated the thermal resistance of the CNPs was lower than the pith cellulose. The optimal CNP with highly cationic charges, good stability and acceptable thermostability might be considered as one of the alternatively renewable reinforcement additives for nanocomposite production.     

Ultrasound-assisted multilayer Pickering emulsion fabricated by WPI-EGCG covalent conjugates for encapsulating probiotics in colon-targeted release

This study demonstrated the influences of ultrasound-assisted multilayer Pickering double emulsion capsules on the pasteurization and gastrointestinal digestive viability of probiotic (L. plantarum) strain liquid. Firstly, the role of ultrasonic homogenization on the morphology of W₁/O/W₂ double emulsions were studied. The double emulsion formed by ultrasonic intensity at 285 W had a single and narrow distribution with smallest droplet size. The double emulsion particles were then coated with chitosan(Chi), alginate (Alg), and CaCl₂(Ca). The multilayer emulsion after pasteurization and gastrointestinal digestion both had the highest viability at 5 coating layers, but its particle size (108.65 μm) exceeded the limit of human oral sensory (80 μm). It could be noted that the deposition of 3–4 layers of coating had similar activity after pasteurization/GIT digestion. And droplets with 3 layers of coating were the minimum and most available formulation for encapsulated probiotics (L. plantarum). Hence, the results suggest that the use of ultrasound-assisted multilayer emulsions encapsulated with probiotics in granular food and pharmaceutical applications is a promising strategy.