Recent advances of ultrasound-responsive nanosystems in tumor immunotherapy

Immunotherapy has revolutionized cancer treatment by boosting the immune system and preventing disease escape mechanisms. Despite its potential, challenges like limited response rates and adverse immune effects impede its widespread clinical adoption. Ultrasound (US), known for its safety and effectiveness in tumor diagnosis and therapy, has been shown to significantly enhance immunotherapy when used with nanosystems. High-intensity focused ultrasound (HIFU) can obliterate tumor cells and elicit immune reactions through the creation of immunogenic debris. Low-intensity focused ultrasound (LIFU) bolsters tumor immunosuppression and mitigates metastasis risk by concentrating dendritic cells. Ultrasonic cavitation (UC) produces microbubbles that can transport immune enhancers directly, thus strengthening the immune response and therapeutic impact. Sonodynamic therapy (SDT) merges nanotechnology with immunotherapy, using specialized sonosensitizers to kill cancer cells and stimulate immune responses, increasing treatment success. This review discusses the integration of ultrasound-responsive nanosystems in tumor immunotherapy, exploring future opportunities and current hurdles.

Ultrasound-assisted fabrication of biopolymer materials: A review

There is an urgent need to develop technologies that can physically manipulate the structure of biocompatible and green polymer materials in order to tune their performance in an efficient, repeatable, easy-to-operate, chemical-free, non-contact, and highly controllable manner. Ultrasound technology produces a cavitation effect that promotes the generation of free radicals, the fracture of chemical chain segments and a rapid change of morphology. The cavitation effects are accompanied by thermal, chemical, and biological effects that interact with the material being studied. With its high efficiency, cleanliness, and reusability applications, ultrasound has a vast range of opportunity within the field of natural polymer-based materials. This work expounds the basic principle of ultrasonic cavitation and analyzes the influence that ultrasonic strength, temperature, frequency and induced liquid surface tension on the physical and chemical properties of biopolymer materials. The mechanism and the influence that ultrasonic modification has on materials is discussed, with highlighted details on the agglomeration, degradation, morphology, structure, and the mechanical properties of these novel materials from naturally derived polymers.

Key Points of Advanced Oxidation Processes (AOPs) for Wastewater, Organic Pollutants and Pharmaceutical Waste Treatment: A Mini Review

Advanced oxidation procedures (AOPs) refer to a variety of technical procedures that produce OH radicals to sufficiently oxidize wastewater, organic pollutant streams, and toxic effluents from industrial, hospital, pharmaceutical and municipal wastes. Through the implementation of such procedures, the (post) treatment of such waste effluents leads to products that are more susceptible to bioremediation, are less toxic and possess less pollutant load. The basic mechanism produces free OH radicals and other reactive species such as superoxide anions, hydrogen peroxide, etc. A basic classification of AOPs is presented in this short review, analyzing the processes of UV/H2O2, Fenton and photo-Fenton, ozone-based (O3) processes, photocatalysis and sonolysis from chemical and equipment points of view to clarify the nature of the reactive species in each AOP and their advantages. Finally, combined AOP implementations are favored through the literature as an efficient solution in addressing the issue of global environmental waste management.

Ultrasound regulated flexible protein materials: Fabrication, structure and physical-biological properties

Ultrasound can be used in the biomaterial field due to its high efficiency, easy operation, no chemical treatment, repeatability and high level of control. In this work, we demonstrated that ultrasound is able to quickly regulate protein structure at the solution assembly stage to obtain the designed properties of protein-based materials. Silk fibroin proteins dissolved in a formic acid-CaCl2 solution system were treated in an ultrasound with varying times and powers. By altering these variables, the silks physical properties and structures can be fine-tuned and the results were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), gas permeability and water contact angle measurements. Ultrasonic treatment aids the interactions between the calcium ions and silk molecular chains which leads to increased amounts of intermolecular β-sheets and α-helix. This unique structural change caused the silk film to be highly insoluble in water while also inducing a hydrophilic swelling property. The ultrasound-regulated silk materials also showed higher thermal stability, better biocompatibility and breathability, and favorable mechanical strength and flexibility. It was also possible to tune the enzymatic degradation rate and biological response (cell growth and proliferation) of protein materials by changing ultrasound parameters. This study provides a unique physical and non-contact material processing method for the wide applications of protein-based biomaterials.

A review on recent advances in hydrogen energy, fuel cell, biofuel and fuel refining via ultrasound process intensification

Hydrogen energy is one of the most suitable green substitutes for harmful fossil fuels and has been investigated widely. This review extensively compiles and compares various methodologies used in the production, storage and usage of hydrogen. Sonochemistry is an emerging synthesis process and intensification technique adapted for the synthesis of novel materials. It manifests acoustic cavitation phenomena caused by ultrasound where higher rates of reactions occur locally. The review discusses the effectiveness of sonochemical routes in developing fuel cell catalysts, fuel refining, biofuel production, chemical processes for hydrogen production and the physical, chemical and electrochemical hydrogen storage techniques. The operational parameters and environmental conditions used during ultrasonication also influence the production rates, which have been elucidated in detail. Hence, this review's major focus addresses sonochemical methods that can contribute to the technical challenges involved in hydrogen usage for energy.

Ultrasound-assisted synthesis of RO- and RS-substituted (hetero)acenes via oxo- and thio-Friedel-Crafts/Bradsher reactions

Two heteroatom-variants of the Friedel-Crafts/Bradsher cyclization of o-acetalaryl(aryl)methyl ethers and o-dithioacetalaryl(aryl)methyl thioethers, have been realized with the ultrasound assistance. The environmentally friendly "oxo-variant" (Oxo-F-C/B), proceeding in a medium containing mineral acid and a large amount of water (HCl_aq/CH₃CN) led to a very efficient formation of RO-substituted (hetero)acenes in less than 5 min. In the "thio-variant" (Thio-F-C/B), o-dithioacetalaryl(aryl)methyl thioethers underwent ultrasound-assisted cyclization in nonaqueous medium (FeCl₃/KI/EtOH) in less than 25 min., in lower yields than in the "oxygen variant" to give RS-substituted (hetero)acenes. The RO-(hetero)acenes cyclized at 25-60 °C in aqueous media but did not cyclize in organic solvents while the RS-(hetero)acenes required higher temperatures 55-60 °C and cyclized in organic solvents but did not react in aqueous media. The acceleration of the ultrasound-assisted reactions compared to the reactions carried out under silent conditions exceeded 7500 times in the most effective example of the oxo-variant and on average 2 times for the thio-variant. The plausible reaction mechanisms under ultrasound and silent conditions have been proposed. The ultrasonic mechanism involves disturbing of solvation layers and formation of the reactive ("naked") carbocations upon operation of the shock wave produced by the bubble collapse. The o-acetalaryl(aryl)methyl ethers underwent a selective ultrasound-assisted deacetalization to give o-formylaryl(aryl)methyl ethers, without subsequent cyclization under the acidic reaction conditions.

Modeling the effect of carbon-dioxide gas on cavitation

One of the controlling parameters of the physical and chemical effects produced by acoustic cavitation is the use of dissolved gas as it affects the temperature and pressure obtained at cavity collapse and, the reactions happening in a bubble. It also enhances the nucleation rates by decreasing the threshold required for cavitation by providing dissolved gas nuclei. The present study looks into the effect of carbon dioxide gas on cavitation using a diffusion limited model. The model couples the dynamics of a single bubble with 11 chemical reactions involving 8 reactive species. The effect of mass transport (diffusion of water vapor and radical species) and heat transport (by conduction) is included in the model. Simulations were carried out for different initial compositions of an Ar-CO₂^- bubble and the results were compared with an experimental study reported in the earlier literature. The results have indicated that intensity of collapse decreases with an increase in CO₂ composition in the bubble thereby decreasing the yield of the oxidizing radicals like OH. This is due to the lower polytropic coefficient and higher specific heat of CO₂ compared to that of argon. Also, the bubbles grows to a larger extent with an increase in the dissolved CO₂ concentration thereby accommodating higher amounts of water vapor and ultimately decreasing the temperature obtained at collapse. Simulations were done for a bubble containing a mole fraction of 95% Ar and 5% CO₂ at different values of driving frequencies (213, 355, 647 and 1000kHz) and driving pressure amplitudes (3.22, 5, 7.5 and 10bar). Higher production rate of OH radicals was predicted at a lower driving frequency, for a given driving pressure amplitude and it increased with an increase in the driving pressure amplitude. At a given driving pressure amplitude, the yield of OH radicals decreased with an increase in the CO₂ concentration in the bubble for all the driving frequencies used in the simulations.

Do not drop: mechanical shock in vials causes cavitation, protein aggregation, and particle formation

Industry experience suggests that g-forces sustained when vials containing protein formulations are accidentally dropped can cause aggregation and particle formation. To study this phenomenon, a shock tower was used to apply controlled g-forces to glass vials containing formulations of two monoclonal antibodies and recombinant human growth hormone (rhGH). High-speed video analysis showed cavitation bubbles forming within 30 μs and subsequently collapsing in the formulations. As a result of echoing shock waves, bubbles collapsed and reappeared periodically over a millisecond time course. Fluid mechanics simulations showed low-pressure regions within the fluid where cavitation would be favored. A hydroxyphenylfluorescein assay determined that cavitation produced hydroxyl radicals. When mechanical shock was applied to vials containing protein formulations, gelatinous particles appeared on the vial walls. Size-exclusion chromatographic analysis of the formulations after shock did not detect changes in monomer or soluble aggregate concentrations. However, subvisible particle counts determined by microflow image analysis increased. The mass of protein attached to the vial walls increased with increasing drop height. Both protein in bulk solution and protein that became attached to the vial walls after shock were analyzed by mass spectrometry. rhGH recovered from the vial walls in some samples revealed oxidation of Met and/or Trp residues.

Surfactant-free coating of thiols on gold nanoparticles using sonochemistry: a study of competing processes

A method for the surfactant-free coating of gold nanoparticles with thiols using sonochemistry is presented. The gold nanoparticles were prepared by a modified Zsigmondy method, affording good control over the particle-size distribution, and the thiol coating was performed by the sonication of a biphasic system consisting of a nanoparticle suspension in water and thiols in toluene. The effects of two important reaction parameters on the particle morphology, viz. sonication time and thiol concentration, were investigated in detail using transmission electron microscopy. The effect of the thiol chain length was also studied. We show that the morphology of the coated particles is determined through a competition between two opposing effects: particle fusion, due to the sonication conditions, and digestive ripening, due to the action of the thiols. Additionally, we illustrate the utility of our technique for various applications, including surface-enhanced Raman scattering from bound molecules, and further functionalization using a thiol-exchange reaction. Our technique paves the way for an efficient synthesis of thiol-coated AuNPs of different shapes and sizes, suitable for a range of diverse applications.

Calorimetric study of the energy efficiency for ultrasound-induced radical formation

Energy conversion in sonochemistry is known to be an important factor for the development of industrial applications, however, the strong influence of the physical properties of the liquid on the ultrasound characteristics usually prevents an accurate determination of the chemical effects. In this study, the energy efficiency of the ultrasound-induced radical formation from methyl methacrylate has been investigated. The energy yield can be quantified by comparison of the ultrasonic power that is transferred to the liquid and the radical formation kinetics. Based on this method the influence of temperature and amplitude of the ultrasound horn on the energy efficiency has been determined. The energy yield for the formation of radicals from ultrasonic waves appears to be in the order of 5 x 10(-6) J/J. The energy conversion is the highest at low temperatures and at low amplitudes.

Modeling of Interface Phenomena in Liquid under Vibration, Using the Chemical Model

An analysis of interface phenomena in a liquid under a vibration field is presented, based on the chemical model of vibration in a liquid. The objects studied are a bubble, a solid surface, and a linear macromolecule, in a vibrated liquid. It is concluded that many sonochemical phenomena can be realized in some different (two or more) mechanisms, and mutually stimulate. Inharmonic effects and the influence of distant neighbors are analyzed.

Methods of theoretical study of vibrational phenomena in liquids--comparative analysis

In this review, existing theoretical models of vibrational phenomena in liquids are analyzed and compared. Most attention is paid to sonoluminescence, sonolysis and related phenomena. The criteria of selection of the optimal theoretical model involve analyzing experimental results, its usefulness for evaluation of thermodynamic and other parameters of the liquid under vibration, simplicity of the mathematical solution and the time needed for computing. It is concluded that, according to these criteria, the optimal (between existing models) is the chemical model of vibration in liquid, while the best perspectives are for its combinations with other models.

Degradation of aqueous solution of potassium iodide and sodium cyanide in the presence of carbon tetrachloride

The degradation of potassium iodide, carbon tetrachloride and sodium cyanide has been studied using an ultrasounic probe of 20 kHz frequency. In the case of potassium iodide and sodium cyanide, the rate of degradation was much higher in presence of CCl4. The location of the ultrasonic horn showed a significant effect in the degradation of CCl4.

Kinetics of nitrous acid formation in nitric acid solutions under the effect of power ultrasound

Sonochemical nitrous acid formation was investigated in 0.1-4.0 mol dm(-3) aqueous nitric acid solutions under the effect of power ultrasound with 20 kHz frequency. HNO2 steady-state concentration was obtained under long-time sonication; the excess HNO2 formed is decomposed and evoluted from the solution as NO and NO2 gases. The HNO2 steady-state concentration and the HNO2 initial formation rate depend linearly on the HNO3 concentration and acoustic intensity (1.8-3.5 W cm(-2)) and decrease with rising temperature in the range 21-50 degrees C. The HNO2 formation rate depends on the type of saturating gas as follows: Ar > N2 > He > air. NO and O2 are the major gaseous products of HNO3 sonication. The NO2 accumulation of in the gas phase is observed only when the decomposition of HNO2 formed becomes noticeable. The gaseous products formation rates depend on the HNO3 concentration, acoustic intensity and the type of saturating gas. The mechanism of HNO2 sonochemical formation is assumed to be the thermal decomposition of HNO3 in the gaseous vicinity of collapsing bubbles or in the overheated liquid reaction zone surrounding the cavitational bubbles.