Sonoluminescence and acoustic emission spectra at different stages of cavitation zone development

MOF-Derived Nanoparticles with Enhanced Acoustical Performance for Efficient Mechano-Sonodynamic Therapy

Ultrasound (US) generates toxic reactive oxygen species (ROS) by acting on sonosensitizers for cancer treatment, and the mechanical damage induced by cavitation effects under US is equally significant. Therefore, designing a novel sonosensitizer that simultaneously possesses efficient ROS generation and enhanced mechanical effects is promising. In this study, carbon-doped zinc oxide nanoparticles (C-ZnO) are constructed for mechano-sonodynamic cancer therapy. The presence of carbon (C) doping optimizes the electronic structure, thereby enhancing the ROS generation triggered by US, efficiently inducing tumor cell death. On the other hand, the high specific surface area and porous structure brought about by C doping enable C-ZnO to enhance the mechanical stress induced by cavitation bubbles under US irradiation, causing severe mechanical damage to tumor cells. Under the dual effects of sonodynamic therapy (SDT) and mechanical therapy mediated by C-ZnO, excellent anti-tumor efficacy is demonstrated both in vitro and in vivo, along with a high level of biological safety. This is the first instance of utilizing an inorganic nanomaterial to achieve simultaneous enhancement of ROS production and US-induced mechanical effects for cancer therapy. This holds significant importance for the future development of novel sonosensitizers and advancing the applications of US in cancer treatment.

Ultrasound-excited temozolomide sonosensitization induces necroptosis in glioblastoma

Temozolomide (TMZ) has been determined to be the chemotherapeutic drug with efficacy for glioblastoma (GBM). Thus, potentiating the therapeutic effect of TMZ can undoubtedly yield twice the result with half the effort. In this study, we found for the first time that TMZ can produce reactive oxygen species (ROS) under the influence of ultrasound (US). This property allows TMZ-US therapy to have better efficacy in the treatment of GBM. Given that the increasing use of US in central nervous system (CNS) diseases and the importance of TMZ for GBM therapy, our results will facilitate the development of TMZ-associated glioblastoma therapies. Moreover, we found that chemotherapeutic drugs might have the ability to generate ROS under the excitation of US. On a larger scale, our findings may be applicable to a wide range of known drugs.

Insight into Sonoluminescence Augmented by ZnO-Functionalized Nanoparticles

Recent advances in optical imaging techniques rely on the use of nanosized contrast agents for in vitro and in vivo applications. We report on an imaging method based on the inertial cavitation of ultrasound-irradiated water solutions that lead to sonoluminescence (SL), here, newly proposed in combination with semiconductor nanoparticles, in particular, aminopropyl-functionalized zinc oxide nanocrystals. The obtained measurements confirm the ability of such nanocrystals to increase the sonoluminescence emission, together with the ability to modify the SL spectrum when compared to the pure water behavior. In particular, it is shown that the UV component of SL is absorbed by the semiconductor behavior that is also confirmed in different biologically relevant media. Finally, optical images of nanocrystal-assisted SL are acquired for the first time, in particular, in biological buffers, revealing that at low ultrasound intensities, SL is measurable only when the nanocrystals are present in solution. All of these results witness the role of amine-functionalized zinc oxide nanocrystals for sonoluminescence emission, which makes them very good candidates as efficient nanocontrast agents for SL imaging for biological and biomedical applications.

Sonoluminescence emission spectra of a 3.6 MHz HIFU in sweeping mode

Use of sweeping mode with a 3.6 MHz High Intensity Focused Ultrasound (HIFU) allows cavitation activity to be controlled. This is especially true in the pre-focal zone where the high concentration of bubbles acts as an acoustic reflector and quenches cavitation above this area. Previous studies attributed the enhancement of cavitation activity under negative sweep to the activation of more bubble nuclei, requiring deeper investigations. After mapping this activity with SCL measurements, cavitation noise spectra were recorded. The behavior of the acoustic broadband noise follows the sonochemical one i.e., showing the same attenuation (positive scan) or intensification (negative scan) of cavitational activity. In 1 M NaCl 3.7 mM 2-propanol solution saturated by a mixture of Ar-15.5%O₂-2.2%N₂, intensities of SL spectra are high enough to allow detection of several molecular emissions (OH, NH, C₂, Na) under negative frequency sweeps. This is the first report of molecular emissions at such high frequency. Their intensities are low, and they are very broad, following the trend obtained at fixed frequency up to 1 MHz. Under optimized conditions, CN emission chosen as a spectroscopic probe is strong enough to be simulated, which is reported for the first time at such high frequency. The resulting characteristics of the plasma do not show any spectral difference, so bubble nature is the same in the pre-and post-focal zone under different sweeping parameters. Consequently, SL and SCL intensification was not related to a change in plasma nature inside the bubbles but to the number of cavitation bubbles.

Low-intensity pulsed ultrasound-generated singlet oxygen induces telomere damage leading to glioma stem cell awakening from quiescence

Cancer stem cells, quiescent and drug resistant, have become a therapeutic target. Unlike high-intensity focused ultrasound directly killing tumor, low-intensity pulsed ultrasound (LIPUS), a new noninvasive physical device, promotes pluripotent stem cell differentiation and is primarily applied in tissue engineering but rarely in oncotherapy. We explored the effect and mechanism of LIPUS on glioma stem cell (GSC) expulsion from quiescence. Here, we observed that LIPUS led to attenuated expression of GSC biomarkers, promoted GSC escape from G0 quiescence, and significantly weakened the Wnt and Hh pathways. Of note, LIPUS transferred sonomechanical energy into cytochrome c and B5 proteins, which converted oxygen molecules into singlet oxygen, triggering telomere crisis. The in vivo and in vitro results confirmed that LIPUS enhanced the GSC sensitivity to temozolomide. These results demonstrated that LIPUS "waked up" GSCs to improve their sensitivity to chemotherapy, and importantly, we confirmed the direct targeted proteins of LIPUS in GSCs.

The bright side of sound: perspectives on the biomedical application of sonoluminescence

Light is a physical phenomenon that is very important to human life, and has been investigated in its nature, behaviour and properties throughout human history although the most impressive improvements in the use of light in human activities, and of course in medicine, began just two centuries ago. However, despite the enormous progress in diagnosis, therapy and surgery to assess health and treat diseases, the delivery of light sources in vivo remains a challenge. In this regard, several strategies have been developed to overcome this drawback, the most interesting of which is the involvement of ultrasound. In this review, the authors examine how ultrasound may improve light delivery in vivo with a special emphasis on one of the most intriguing ultrasound-mediated phenomena called sonoluminescence, which is the conversion of mechanical ultrasound energy into light.

Metalloporphyrins in Medicine: From History to Recent Trends

The history of metalloporphyrins dates back more than 200 years ago. Metalloporphyrins are excellent catalysts, capable of forming supramolecular systems, participate in oxygen photosynthesis, transport, and used as contrast agents or superoxide dismutase mimetics. Today, metalloporphyrins represent complexes of conjugated π-electron system and metals from the entire periodic system. However, the effect of these compounds on living systems has not been fully understood, and researchers are exploring the properties of metalloporphyrins thereby extending their further application. This review provides an overview of the variety of metalloporphyrins that are currently used in different medicine fields and how metalloporphyrins became the subject of scientists' interest. Currently, metalloporphyrins utilization has expanded significantly, which gave us an opprotunuty to summarize recent progress in metalloporphyrins derivatives and prospects of their application in the treatment and diagnosis of different diseases.

Interpreting the influence of liquid temperature on cavitation collapse intensity through bubble dynamic analysis

The violent collapse of inertial bubbles generates high temperature inside and emits strong impulsive pressure. Previous tests on sonoluminescence and cavitation erosion showed that the influence of liquid temperature on these two parameters is different. In this paper, we conducted a bubble dynamic analysis to explore the mechanism of the temperature effect and account for the above difference. The results show that the increase of vapor at higher liquid temperatures changes both the external compression pressure and the internal cushion and is responsible for the variation of bubble collapse intensity. The different trends of the collapsing temperature and emitted sound pressure are caused by the energy distribution during the bubble collapse. Moreover, a series of simulations are conducted to establish the distribution map of the optimum liquid temperature where the collapse intensity is maximized. The relationship between the collapse intensity and the radial dynamics of the bubble is discussed and the reliable indicator is identified. This study provides a clear picture of how the thermodynamic process changes cavitation aggressiveness and enriches the understanding of this complex thermal-hydrodynamic phenomenon.

Bubble dynamics and cavitation intensity in milli-scale channels under an ultrasonic horn

Under a vibrating ultrasonic horn device, intense cavitation occurs but is restricted to a small volume due to strong attenuation effects. In this study, milli-scale channels were introduced under the horn. The effect of this on the cavitation development and intensity within the channels were explored. High speed videography of up to 100,000 fps and acoustic signal acquisition through hydrophone were conducted. Cavitation intensity was observed to increase within the channels as compared to free field condition. Bubble density increased with a decrease in channel diameter and a rise in ultrasonic amplitude. Furthermore, an intriguing phenomenon of large bubble cluster formation near the channel exit (20 mm away from the horn surface) was detected. The oscillation behaviour of these clusters is dependent on both channel diameter and ultrasonic amplitude. At the maximum ultrasonic amplitude, the clusters reached maximum radiuses exceeding 3 mm and collapsed violently. Repetitive transient collapses near the exit region suggest that the introduction of milli-scale channels could extend the effective cavitation zone length and enhance the overall cavitation intensity under an ultrasonic horn.

A novel Z-scheme sonocatalyst system, Er3+:Y3Al5O12@Ni(Fe0.05Ga0.95)2O4-Au-BiVO4, and application in sonocatalytic degradation of sulfanilamide

A novel Z-scheme coated composite, Er³⁺:Y₃Al₅O₁₂@Ni(Fe_0.05Ga_0.95)₂O₄-Au-BiVO₄, was designed for sonocatalytic degradation of sulfanilamide and fabricated by sol-hydrothermal and calcination methods. The prepared sample was characterized by X-ray diffractometer (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), UV-vis diffuse reflectance spectra (DRS), fourier transform infrared (FT-IR) spectra, Raman spectra and photoluminescence (PL) spectra. In Er³⁺:Y₃Al₅O₁₂@Ni(Fe_0.05Ga_0.95)₂O₄-Au-BiVO₄, Ni(Fe_0.05Ga_0.95)₂O₄ and BiVO₄ form a Z-scheme sonocatalytic system, Er³⁺:Y₃Al₅O₁₂ as an up-conversion luminescence agent (from visible-light to ultraviolet-light) provides the ultraviolet-light for satisfying the energy demand of wide band-gap Ni(Fe_0.05Ga_0.95)₂O₄ and Au nanoparticles as co-catalyst forms more active sites to enrich electrons. Also, Au nanoparticles as conductive channels promotes the electrons (e^-) from conduction band of BiVO₄ to transfer to valence band of Ni(Fe_0.05Ga_0.95)₂O₄. Due to the characteristics of valence state diversity, the Fe³⁺ and V⁵⁺ constitute a redox reaction recombination system, which can also push electrons (e^-) on conduction band of BiVO₄ to quickly transfer to valence band of Ni(Fe_0.05Ga_0.95)₂O₄. The sonocatalytic activity of Er³⁺:Y₃Al₅O₁₂@Ni(Fe_0.05Ga_0.95)₂O₄-Au-BiVO₄ nanocomposite was detected through degradation of sulfanilamide under ultrasonic irradiation. A high sonocatalytic degradation ratio (95.64%) of sulfanilamide can be obtained when the conditions of 10.00 mg/L sulfanilamide, 1.00 g/L Er³⁺:Y₃Al₅O₁₂@Ni(Fe_0.05Ga_0.95)₂O₄-Au-BiVO₄, 300 min ultrasonic irradiation and 100 mL total volume were adopted. Some factors such as ultrasonic irradiation time and cycle number on the sonocatalytic degradation efficiency are also investigated by using TOC and UV-vis spectroscopy. Subsequently, the effects of hydroxyl radicals (OH) and hole scavengers were investigated to elaborate the mechanism. The researches show that the prepared Z-scheme Er³⁺:Y₃Al₅O₁₂@Ni(Fe_0.05Ga_0.95)₂O₄-Au-BiVO₄ coated composite displayed an excellent sonocatalytic activity in degradation of sulfanilamide under ultrasonic irradiation.