Structural and permeability sensitivity of cells to low intensity ultrasound: Infrared and fluorescence evidence in vitro

Sono-promoted piezocatalysis and low-dose drug penetration for personalized therapy via tumor organoids

Chemotherapy is a widely used cancer treatment, however, it can have notable side effects owing to the high-doses of drugs administered. Sonodynamic therapy (SDT) induced by sonosensitizers has emerged as a promising approach to treat cancer, however, there is limited research evaluating its therapeutic effects on human tumors. In this study, we introduced a dual therapy that combines low-dose chemotherapeutic drugs with enhanced sonodynamic therapy, utilizing barium titanate (BaTiO3, BTO) nanoparticles (NPs) as sonosensitizers to treat tumor organoids. We demonstrated that ultrasound could improve the cellular uptake of chemotherapy drugs, while the chemotherapeutic effect of the drugs made it easier for BTO NPs to enter tumor cells, and the dual therapy synergistically inhibited tumor cell viability. Moreover, different patient-derived tumor organoids exhibited different sensitivities to this therapy, highlighting the potential to evaluate individual responses to combination therapies prior to clinical intervention. Furthermore, this dual therapy exhibited therapeutic effects equivalent to those of high-dose chemotherapy drugs on drug-resistant tumor organoids and showed the potential to enhance the efficacy of killing drug-resistant tumors. In addition, the biosafety of the BTO NPs was successfully verified in live mice via oral administration. This evidence confirms the reliable and safe nature of the dual therapy approach, making it a feasible option for precise and personalized therapy in clinical applications.

Basic research on curcumin in cervical cancer: Progress and perspectives

Curcumin is a polyphenolic substance extracted from plants such as Curcuma longa, Curcuma zedoaria, and radix curcumae, and it has attracted much attention because of the anti-inflammatory, antioxidant, anti-tumor, antibacterial and other multiple pharmacological effects. Cervical cancer is one of the most common malignant tumors in women. With the application of HPV (human papillomavirus) vaccine, the incidence of cervical cancer is expected to be reduced, but it remains difficult to promote the vaccine among low-income population. As a commonly used food additive, curcumin has recently been found to have a significant therapeutic effect in the treatment of cervical cancer. In recent years, numerous in vitro and in vivo studies have found that curcumin can have significant efficacy in anti-cervical cancer treatment by promoting apoptosis, inhibiting tumour cell proliferation, metastasis and invasion, inhibiting HPV and inducing autophagy in tumour cells. However, due to poor water solubility, rapid catabolism, and low bioavailability of curcumin, studies on curcumin derivatives and novel formulations are increasing. Curcumin has a wide range of mechanisms of action against cervical cancer and may become a novel antitumor drug in the future, opening up new ideas for the research of curcumin in the field of antitumor. There is a lack of systematic reviews on the mechanism of action of curcumin against cervical cancer. Therefore, this study is a review of the literature based on the mechanism of action of curcumin against cervical cancer, with a view to providing reference information for scientific and clinical practitioners.

Therapeutic Ultrasound Effects on Human Induced Pluripotent Stem Cell Cardiomyocytes Measured Optically and with Spectral Ultrasound

To the best of our knowledge, therapeutic ultrasound (TUS) is thus far an unexplored means of delivering mechanical stimulation to cardiomyocyte cultures, which is necessary to engineer a more mature cardiomyocyte phenotype in vitro. Spectral ultrasound (SUS) may provide a way to non-invasively, non-disruptively and inexpensively monitor growth and change in cell cultures over long periods. Compared with other measurement methods, SUS as an acoustic measurement tool will not be affected by an acoustic therapy, unlike electrical measurement methods, in which motion caused by acoustic therapy can affect measurements. Further SUS has the potential to provide functional as well as morphological information in cell cultures. Human induced pluripotent stem cell cardiomyocytes (iPS-CMs) were imaged with calcium fluorescence microscopy while TUS was being applied. TUS was applied at 600 kHz and 1, 3.4 and 6 W/cm² for a continuous 1 s pulse. Measures of the instantaneous beat frequency, repolarization rate and calcium spike amplitude were calculated from the fluorescence data. At 600 kHz, TUS at 1 and 6 W/cm² had significant effects on the shortening of both the repolarization rate and instantaneous beat rate of the iPS-CMs (p < 0.05), while TUS at 3.4 and 6 W/cm² had significant effects on the shortening of the calcium spike amplitude (p < 0.05). Three SUS measures and one gray-level measure were captured from the iPS-CM monolayers while they were simultaneously being imaged with calcium-labeled confocal microscopy. The gray-level measure performed the best of all SUS measures; however, it was not reliable enough to produce a consistent determination of the beat rate of the cell. Finally, SUS measures were captured using three different transducers while simultaneously applying TUS. A center-of-mass (COM) measure calculated from the wavelet transform scalogram of the time-averaged radiofrequency data revealed that SUS was able to detect a change in the frequency content of the reflected ultrasound at 1 and 6 W/cm² before and after ultrasound application (p < 0.05), showing promise for the ability of SUS to measure changes in the beating behavior of iPS-CMs. Overall, SUS is promising as a method for constant monitoring of dynamic cell and tissue culture and growth.

Effect of 1-MHz ultrasound on the proinflammatory interleukin-6 secretion in human keratinocytes

Keratinocytes, the main cell type of the skin, are one of the most exposed cells to environmental factors, providing a first defence barrier for the host and actively participating in immune response. In fact, keratinocytes express pattern recognition receptors that interact with pathogen associated molecular patterns and damage associated molecular patterns, leading to the production of cytokines and chemokines, including interleukin (IL)-6. Herein, we investigated whether mechanical energy transported by low intensity ultrasound (US) could generate a mechanical stress able to induce the release of inflammatory cytokine such IL-6 in the human keratinocyte cell line, HaCaT. The extensive clinical application of US in both diagnosis and therapy suggests the need to better understand the related biological effects. Our results point out that US promotes the overexpression and secretion of IL-6, associated with the activation of nuclear factor-κB (NF-κB). Furthermore, we observed a reduced cell viability dependent on exposure parameters together with alterations in membrane permeability, paving the way for further investigating the molecular mechanisms related to US exposure.

A Promising Platform of Magnetic Nanofluid and Ultrasonic Treatment for Cancer Hyperthermia Therapy: In Vitro and in Vivo Study

Localized hyperthermia is a very promising cancer therapy approach especially when stimulated by the exceptional properties of iron oxide magnetic nanoparticles (MNPs). This approach is a highly site-specific method for localized heating of bodily tissue without any harmful side effects that could revolutionize the practice of cancer therapy. The main objective of this study was to evaluate the cancer cell-destroying capability of MNPs in combination with ultrasound treatment as an innovative sonomagnetic cancer therapy. Magnetic nanofluids (MNFs) were synthesized by co-precipitation/sonochemical techniques in an aqueous medium without any surfactant and/or capping agent. The physicochemical characteristics of the prepared MNFs were investigated with scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, Fourier transform infrared and vibrating sample magnetometry. The MNFs was used as a mediator and sonosensitizer to destroy tumor tissue when irradiated by ultrasound waves. The antitumor efficiency of MNFs in combination with pulsed ultrasound (1.5 W/cm², 1 MHz) was evaluated in vitro and in vivo. In vitro efficacy was estimated by determining the cell viability of Ehrlich ascites carcinoma cells. For in vivo experiments, female mice were inoculated subcutaneously with Ehrlich carcinoma cells to establish solid Ehrlich carcinoma. The cytotoxic concentration of MNFs (400 µg/mL) was injected intratumorally and exposed to pulsed ultrasound (1.5 W/cm², 1 MHz). The cytotoxic effect was determined in terms of tumor growth rate, apoptosis and necrosis. Our results revealed that MNFs in the presence of pulsed ultrasound cause a significant increase in the cytotoxicity effect on tumor cells. This study illustrates the high efficiency of cancer therapy as assisted by both ultrasound and magnetic nanofluid.

The influence of hyperglycemia on the safety of ultrasound in retinal pigment epithelial cells

Ultrasound (US) assisted drug delivery is receiving interest in treating posterior eye diseases, such as diabetic retinopathy due to its ability to maximize drug penetration into difficult to reach tissues. Despite its promise, the technique has only been investigated using healthy cell and tissue models, with no evidence to date about its safety in active disease. As a result, the aim of this study was to evaluate the safety of US administration in vitro in retinal pigment epithelial cells under normal and high glucose conditions. US protocols within the presently accepted safety threshold were applied and their influence on cell membrane and tight junction integrity as well as intracellular inflammation was evaluated using lactate dehydrogenase (LDH), zona occludens-1 (ZO-1), fluorescein isothiocyanate (FITC)-dextran dye leak and nuclear factor-kappaB (NF-κB) assays, respectively. Under high glucose conditions, US application increased LDH release and resulted in loss of ZO-1 labeling at 2 h; however, normal levels were restored within 24 h. US within its safety parameters did not induce any FITC-dextran dye leak or NF-κB nuclear translocation in normal or high glucose conditions. In conclusion, our results suggest that while high glucose conditions increase cell susceptibility to US-mediated stress, basal conditions can be restored within 24 h without long-lasting cell damage.

Ultrasound delivery of Surface Enhanced InfraRed Absorption active gold-nanoprobes into fibroblast cells: a biological study via Synchrotron-based InfraRed microanalysis at single cell level

Ultrasound (US) induced transient membrane permeabilisation has emerged as a hugely promising tool for the delivery of exogenous vectors through the cytoplasmic membrane, paving the way to the design of novel anticancer strategies by targeting functional nanomaterials to specific biological sites. An essential step towards this end is the detailed recognition of suitably marked nanoparticles in sonoporated cells and the investigation of the potential related biological effects. By taking advantage of Synchrotron Radiation Fourier Transform Infrared micro-spectroscopy (SR-microFTIR) in providing highly sensitive analysis at the single cell level, we studied the internalisation of a nanoprobe within fibroblasts (NIH-3T3) promoted by low-intensity US. To this aim we employed 20 nm gold nanoparticles conjugated with the IR marker 4-aminothiophenol. The significant Surface Enhanced Infrared Absorption provided by the nanoprobes, with an absorbance increase up to two orders of magnitude, allowed us to efficiently recognise their inclusion within cells. Notably, the selective and stable SR-microFTIR detection from single cells that have internalised the nanoprobe exhibited clear changes in both shape and intensity of the spectral profile, highlighting the occurrence of biological effects. Flow cytometry, immunofluorescence and murine cytokinesis-block micronucleus assays confirmed the presence of slight but significant cytotoxic and genotoxic events associated with the US-nanoprobe combined treatments. Our results can provide novel hints towards US and nanomedicine combined strategies for cell spectral imaging as well as drug delivery-based therapies.

In vitro effects of 1-MHz ultrasound on the mitotic spindle

The effects of ultrasound on the cytoskeleton, comprising microtubules, had been studied decades ago. Nonetheless, very little attention has been paid to the effects of ultrasound on the mitotic spindle, which is also formed by microtubules. In this study, we treated human fibroblasts and human cancer cells (HeLa and MCF-7) with 1-MHz ultrasound at low intensities (70, 140, and 300 mW/cm² ). In all cell lines, 5 min after the end of sonication, we found an intensity-dependent increase of mitotic abnormalities (including multipolar spindles). Two hours after sonication, these abnormalities were present, but at much lower frequencies. Twenty-four hours after sonication, mitotic abnormalities were at the same level of untreated samples, suggesting a transient effect due to ultrasound. Beside abnormalities of the mitotic spindle, we also observed an increase of metaphases with nonaligned chromosomes. The mitotic index of fibroblasts and HeLa cells, two hours after sonication, showed an intensity-dependent decrease; this was not observed in MCF-7 cells. In agreement with this last result, ultrasound-induced growth inhibition (which was also intensity-dependent) was more marked in fibroblasts and HeLa cells compared to MCF-7 cells. This work indicates that therapeutic ultrasound, even at intensities below the cavitation threshold, can affect genome integrity, showing the need to increase the knowledge of the potential risks of ultrasound to human health. Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc.

Long-term physical evolution of an elastomeric ultrasound contrast microbubble

HYPOTHESIS

One of the main assets of crosslinked polymer-shelled microbubbles (MBs) as ultrasound-active theranostic agents is the robustness of the shells, combined with the chemical versatility in modifying the surface with ligands and/or drugs. Despite the long shelf-life, subtle modifications occur in the MB shells involving shifts in acoustic, mechanical and structural properties.

EXPERIMENTS

We carried out a long-term morphological and acoustic evolution analysis on elastomeric polyvinyl-alcohol (PVA)-shelled MBs, a novel platform accomplishing good acoustic and surface performances in one agent. Confocal laser scanning microscopy, acoustic spectroscopy and AFM nanomechanics were integrated to understand the mechanism of PVA MBs ageing. The changes in the MB acoustic properties were framed in terms of shell thickness and viscoelasticity using a linearised oscillation theory, and compared to MB morphology and to nanomechanical analysis.

FINDINGS

We enlightened a novel, intriguing ageing time evolution of the PVA MBs with double behaviour with respect to a crossover time of ∼50 days. Before, significant changes occur in MB stiffness and shell thickness, mainly due to a massive release of entangled PVA chains. Then, the MB resonance frequency increases together with shell thickening and softening. Our benchmark study is of general interest for emerging viscoelastomeric bubbles towards personalised medicine.

Differential effects on membrane permeability and viability of human keratinocyte cells undergoing very low intensity megasonic fields

Among different therapeutic applications of Ultrasound (US), transient membrane sonoporation (SP) - a temporary, non-lethal porosity, mechanically induced in cell membranes through US exposure - represents a compelling opportunity towards an efficient and safe drug delivery. Nevertheless, progresses in this field have been limited by an insufficient understanding of the potential cytotoxic effects of US related to the failure of the cellular repair and to the possible activation of inflammatory pathway. In this framework we studied the in vitro effects of very low-intensity US on a human keratinocyte cell line, which represents an ideal model system of skin protective barrier cells which are the first to be involved during medical US treatments. Bioeffects linked to US application at 1 MHz varying the exposure parameters were investigated by fluorescence microscopy and fluorescence activated cell sorting. Our results indicate that keratinocytes undergoing low US doses can uptake drug model molecules with size and efficiency which depend on exposure parameters. According to sub-cavitation SP models, we have identified the range of doses triggering transient membrane SP, actually with negligible biological damage. By increasing US doses we observed a reduced cells viability and an inflammatory gene overexpression enlightening novel healthy relevant strategies.

Complex interfaces in "phase-change" contrast agents

In this paper we report on the study of the interface of hybrid shell droplets encapsulating decafluoropentane (DFP), which exhibit interesting potentialities for ultrasound (US) imaging. The fabrication of the droplets is based on the deposition of a dextran methacrylate layer onto the surface of surfactants. The droplets have been stabilized against coalescence by UV curing, introducing crosslinks in the polymer layer and transforming the shell into an elastomeric membrane with a thickness of about 300 nm with viscoelastic behaviour. US irradiation induces the evaporation of the DFP core of the droplets transforming the particles into microbubbles (MBs). The presence of a robust crosslinked polymer shell introduces an unusual stability of the droplets also during the core phase transition and allows the recovery of the initial droplet state after a few minutes from switching off US. The interfacial tension of the droplets has been investigated by two approaches, the pendant drop method and an indirect method, based on the determination of the liquid ↔ gas transition point of DFP confined in the droplet core. The re-condensation process has been followed by capturing images of single MBs by confocal microscopy. The time evolution of MB relaxation to droplets was analysed in terms of a modified Church model to account for the structural complexity of the MB shell, i.e. a crosslinked polymer layer over a layer of surfactants. In this way the microrheology parameters of the shell were determined. In a previous paper (Chem. Commun., 2013, 49, 5763-5765) we showed that these systems could be used as ultrasound contrast agents (UCAs). In this work we substantiate this view assessing some key features offered by the viscoelastic nature of the droplet shell.

Effect of low-intensity pulsed ultrasound on posterolateral lumbar fusion of rabbit

OBJECTIVE

To observe the effect of low-intensity pulsed ultrasound in the posterolateral lumbar fusion of rabbit.

METHODS

A total of 48 New Zealand white rabbits were randomly divided into the observation group and control group, including the autogenous iliac observation group, artificial bone observation group, artificial bone control group and autogenous iliac control group according to the different bone grafting. The posterolateral lumbar fusion of rabbits in each group was analyzed and compared.

RESULTS

After 4 weeks of treatment using the low-intensity pulsed ultrasound, the fusion in the bone grafting area of observation group was good. There was the relatively dense fusion area between the right transverse process and artificial bone. The left transverse process had been completely fused, with the clear bone trabecula through the fusion area. There was no significant fusion sign in the control group. According to the fusion comparison between two groups, the fusion rate of the observation group was 83.3% and it was significantly higher than the one of the control group (37.5%). Results of the comparison were statistically significant (P<0.05). The number of chondrocytes and the increase in the relative gray-scale in the fusion area of the iliac observation group were significantly higher than ones of the iliac control group (P<0.05). The number of chondrocytes and the increase in the relative gray-scale in the fusion area of the artificial bone observation group were significantly higher than ones of the artificial bone control group (P<0.05). The expression of IL-1, IL-6 and IL-17 4 weeks after the treatment of the observation group was significantly lower than the one of the control group, with the statistical significance (P<0.05). It indicated that the treatment of low-intensity pulsed ultrasound could reduce the expression level of inflammatory factors.

CONCLUSIONS

The low-intensity pulsed ultrasound can significantly increase the bone grafting fusion rate of the rabbit's posterolateral lumbar fusion. The possible mechanism is that it promotes the lumbar posterolateral endochondral ossification and reduces the inflammatory reaction.

Potential genotoxic effects of low-intensity ultrasound on fibroblasts, evaluated with the cytokinesis-block micronucleus assay

Although medical ultrasound offers compelling opportunities to improve therapy in principle, progress in the field has been limited because of an insufficient understanding of the potential genotoxic and cytotoxic effects of ultrasound on biological systems. This paper is mainly focused on an in vitro study of effects with respect to genotoxicity and viability induced by 1- and 3-MHz medical ultrasound in murine fibroblasts (NIH-3T3) at low-intensity exposure (spatial peak temporal average intensity Ita<0.1 W/cm(2)). The NIH-3T3 cells constitute a well-characterized in vitro cell model in which a genotoxic effect can be predicted by means of a reliable and precise murine cytokinesis-block micronucleus assay. A statistically significant increase in the incidence of micronuclei was observed in sonicated 3T3 cells. In particular, the effects were more evident at 1 MHz. Moreover, for each frequency investigated, the occurrence of micronuclei was comparatively more frequent with increasing time of exposure. The possible toxicological implications of the medical ultrasound employed herein deal with the existence of a window of exposure parameters (set well below the intensity of ultrasound cavitation) in which some genotoxic effects may occur without significant cytotoxicity. In this respect, they provide new insight toward the correct risk to benefit balancing of ultrasound-based treatments and for designing innovative therapeutic strategies.