Phospholipid bilayer responses to ultrasound-induced microbubble cavitation phenomena

Recent breakthroughs in graphene quantum dot-enhanced sonodynamic and photodynamic therapy

Water-soluble graphene quantum dots (GQDs) have recently exhibited considerable potential for diverse biomedical applications owing to their exceptional optical and chemical properties. However, the pronounced heterogeneity in the composition, size, and morphology of GQDs poses challenges for a comprehensive understanding of the intricate correlation between their structural attributes and functional properties. This variability also introduces complexities in scaling the production processes and addressing safety considerations. Light and sound have firmly established their role in clinical applications as pivotal energy sources for minimally invasive therapeutic interventions. Given the limited penetration depth of light, photodynamic therapy (PDT) predominantly targets superficial conditions such as dermatological disorders, head and neck malignancies, ocular ailments, and early-stage esophageal cancer. Conversely, ultrasound-based sonodynamic therapy (SDT) capitalizes on its superior ability to propagate and focus ultrasound within biological tissues, enabling a diverse range of therapeutic applications, including the management of gliomas, breast cancer, hematological tumors, and modulation of the blood-brain barrier (BBB). Considering the advancements in theranostic and precision therapies, reevaluating these conventional energy sources and their associated sensitizers is imperative. This review introduces three prevalent treatment modalities that harness light and sound stimuli: PDT, SDT, and a synergistic approach that integrates PDT and SDT. This study delineated the therapeutic dynamics and contemporary designs of sensitizers tailored to these modalities. By exploring the historical context of the field and elucidating the latest design strategies, this review underscores the pivotal role of GQDs in propelling the evolution of PDT and SDT. This aspires to stimulate researchers to develop "multimodal" therapies integrating both light and sound stimuli.

Intensified and controllable vaporization of phase-changeable nanodroplets induced by simultaneous exposure of laser and ultrasound

Phase-changeable contrast agents have been proposed as a next-generation ultrasound contrast agent over conventional microbubbles given its stability, longer circulation time and ability to extravasate. Safe vaporization of nanodroplets (NDs) plays an essential role in the practical translation of ND applications in industry and medical therapy. In particular, the exposure parameters for initializing phase change as well as the site of phase change are concerned to be controlled. Compared to the traditional optical vaporization or acoustic droplet vaporization, this study exhibited the potential of using simultaneous, single burst laser and ultrasound incidence as a means of activating phase change of NDs to generate cavitation nuclei with reduced fluence and sound pressure. A theoretical model considering the laser heating, vapor cavity nucleation and growth was established, where qualitative agreement with experiment findings were found in terms of the trend of combined exposure parameters in order to achieve the same level of vaporization outcome. The results indicate that using single burst laser pulse and 10-cycle ultrasound might be sufficient to lower the exposure levels under FDA limit for laser skin exposure and ultrasound imaging. The combination of laser and ultrasound also provides temporal and spatial control of ND vaporization and cavitation nucleation without altering the sound field, which is beneficial for further safe and effective applications of phase-changeable NDs in medical, environmental, food processing and other industrial areas.

Liposomes for encapsulation of liposoluble vitamins (A, D, E and K): Comparation of loading ability, storage stability and bilayer dynamics

To understand the encapsulation difference and stability mechanism of nanoliposomes (NLPs) loaded with different kinds and loads of liposoluble vitamins (LSV, including VA, VD, VE, and VK), the physicochemical stability during three-months storage and bilayer membrane properties of LSV-NLPs were evaluated. The results suggested that VD and VE were not suitable for high-load (≥30 wt%) encapsulation, but the stability of other LSV-NLPs was excellent during storage. Their particle size was less than 100 nm, the polydispersity index was less than 0.3, and the retention rate of VE and VK remained above 85 %. LSV encapsulation inhibited malondialdehyde production, decreased liposome surface roughness, and improved nanoliposome rigidity. The order of occupying capacity of LSV to the hydrophobic zone of the bilayer was VK＞VD＞VE＞VA, and the stability of LSV located in the hydrophobic region was better. Except for high-load VD and VE, the other LSV encapsulation increased the microviscosity of the lipid-water interface and hydrophobic zone by 0.5 ∼ 7.1 times and 0.5 ∼ 20 times, respectively. The accumulation of acyl chain was enhanced by 0.2 ∼ 4 times, and the interchain longitudinal and intra-chain transverse order degree was increased by 10.89 %∼144.35 % and 3.26 %∼115.52 %, respectively. High microviscosity and tight chain stacking limited bilayer fluidity and thus improve LSV-NLPs stability. This work will contribute to the application of nanoliposomes as liposoluble vitamin carriers in the food industry.

Application of nanosonosensitizer materials in cancer sono-dynamic therapy

Sonodynamic therapy (SDT) is a novel non-invasive treatment for cancer combining low-intensity ultrasound and sonosensitizers. SDT activates sonosensitizers through ultrasound, releasing energy and generating reactive oxygen species to kill tumor cells. Compared with traditional photodynamic therapy (PDT), SDT is a promising anti-cancer therapy with the advantages of better targeting, deeper tissue penetration, and higher focusing ability. With the development and broad application of nanomaterials, novel sonosensitizers with tumor-targeting specificity can deliver to deep tumors and enhance the tumor microenvironment. In this review, we first review the mechanisms of sonodynamic therapy. In addition, we also focus on the current types of sonosensitizers and the latest design strategies of nanomaterials in sonosensitizers. Finally, we summarize the combined strategy of sonodynamic therapy.

Organic Sonosensitizers for Sonodynamic Therapy: From Small Molecules and Nanoparticles toward Clinical Development

Sonodynamic therapy (SDT) is a novel noninvasive therapeutic modality that combines low-intensity ultrasound and sonosensitizers. Versus photo-mediated therapy, SDT has the advantages of deeper tissue penetration, high accuracy, and less side effects. Sonosensitizers are critical for therapeutic efficacy during SDT and organic sonosensitizers are important because of their clear structure, easy monitoring, evaluation of drug metabolism, and clinical transformation. Notably, nanotechnology can be used in the field of sonosensitizers and SDT to overcome the inherent obstacles and achieve sustainable innovation. This review introduces organic small molecule sonosensitizers, nano organic sonosensitizers, and their clinical translation by providing ideas and references for the design of sonosensitizers and SDT so as to promote its transformation to clinical applications in the future.