Low-intensity Ultrasound Irradiation Research Articles

Ultrasound-Responsive Nanodelivery System of GPC3-Targeting and Sonosensitizer for Visualized Hepatocellular Carcinoma Therapy.

The incidence of hepatocellular carcinoma (HCC) is continuously increasing, and the mortality rate remains high. Thus, more effective strategies are needed to improve the treatment of HCC. In this study, we report the use of a visualized glypican-3 (GPC3)-targeting nanodelivery system (named GC-NBs) in combination with sonodynamic therapy (SDT) to enhance the therapeutic efficacy for treating HCC. The obtained nanodelivery system could actively target hepatocellular carcinoma cells and achieve ultrasound imaging through phase changes into nanobubbles under low-intensity ultrasound irradiation. Meanwhile, the released chlorine e6 (Ce6) after the nanobubbles collapse could lead to the generation of reactive oxygen species (ROS) under ultrasound irradiation to induce SDT. Both in vitro and in vivo experiments have shown that GC-NBs can accumulate in tumour areas and achieve sonodynamic antitumour therapy under the navigation action of glypican-3-antibody (GPC3-Ab). Furthermore, in vitro and in vivo experiments did not show significant biological toxicity of the nanodelivery system. Moreover, GC-NBs can be imaged with ultrasound, providing personalized treatment monitoring. GC-NBs enable a visualized antitumour strategy from a targeted sonodynamic perspective by combining tumour-specific targeting and stimuli-responsive controlled release into a single system.

Copper-Single-Atom Coordinated Nanotherapeutics for Enhanced Sonothermal-Parallel Catalytic Synergistic Cancer Therapy.

Phototherapy and sonotherapy are recognized by scientific medicine as effective strategies for treating certain cancers. However, these strategies have limitations such as an inability to penetrate deeper tissues and overcome the antioxidant tumor microenvironment. In this study, a novel "BH" interfacial-confined coordination strategy to synthesize hyaluronic acid-functionalized single copper atoms dispersed over boron imidazolate framework-derived nanocubes (HA-NC_Cu) to achieve sonothermal-catalytic synergistic therapy is reported. Notably, HA-NC_Cu demonstrates exceptional sonothermal conversion performance under low-intensity ultrasound irradiation, attained through intermolecular lattice vibrations. In addition, it shows promise as an efficient biocatalyst, able to generate high-toxicity hydroxyl radicals in response to tumor-endogenous hydrogen peroxide and glutathione. Density functional theory calculations reveal that the superior parallel catalytic performance of HA-NC_Cu originates from the CuN4 C/B active sites. Both in vitro and in vivo evaluations consistently demonstrate that the sonothermal-catalytic synergistic strategy significantly improves tumor inhibition rate (86.9%) and long-term survival rate (100%). In combination with low-intensity ultrasound irradiation, HA-NC_Cu triggers a dual death pathway of apoptosis and ferroptosis in MDA-MB-231 breast cancer cells, comprehensively limiting primary triple-negative breast cancer. This study highlights the applications of single-atom-coordinated nanotherapeutics in sonothermal-catalytic synergistic therapy, which may create new opportunities in biomedical research.

Fractionated Sonodynamic Therapy Using Gold@Poly(ortho-aminophenol) Nanoparticles and Multistep Low-Intensity Ultrasound Irradiation to Treat Melanoma Cancer: In Vitro and In Vivo Studies.

Cancer treatment using ultrasound irradiation with low intensities along with a sonosensitizer has been found to have significant advantages, such as high penetration depth in tissues, non-invasive therapeutic character, minor side effects, good patient adherence and preferential tumor area treatment. In the present study, gold nanoparticles covered by poly(ortho-aminophenol) (Au@POAP NPs) were synthesized and characterized as a new sonosensitizer. We investigated Au@POAP NPs efficacy on fractionated ultrasound irradiation for treatment of melanoma cancer in vitro as well as in vivo. In vitro examinations revealed that although Au@POAP NPs (with a mean size of 9.8 nm) alone represented concentration-dependent cytotoxicity against the B16/F10 cell line, multistep ultrasound irradiation (1 MHz frequency, 1.0 W/cm2 intensity, 60 s irradiation time) of the cells in the attendance of Au@POAP NPs led to efficient cell sonodynamic therapy (SDT) and death. Histological analyses revealed that in vivo fractionated SDT toward melanoma tumors of male balb/c mice led to no residual viable tumor cell after 10 d. A deep sonosensitizing effectiveness of Au@POAP NPs on fractionated low-intensity ultrasound irradiation was attained with the main mechanism of tumor cell eradication of promotion of apoptosis or necrosis through dramatically increased reactive oxygen species levels.

In vitro study about prevention of vascular reocclusion by low intensity ultrasonic irradiation.

For the treatment of acute ischemic stroke, the current standard of care is thrombolysis by the administration of intravenous (IV) recombinant tissue-type plasminogen activator (rt-PA). Although this approach is proven to be effective, reocclusion within 24 hours occurs in about 20% of patients who receive recanalization by rt-PA. In addition, the administration of anticoagulants within 24 hours after IV rt-PA increases the risk of intracranial hemorrhage; therefore, treatment with anticoagulants is contraindicated in this population. To address the need for an approach to sustain the effects of thrombolysis prevent blood vessel reocclusion without the use of anticoagulants, this study proposes a novel method using a low-intensity ultrasound (US) irradiation. An in vitro thrombus-growth model, in a latex rubber container was developed to study the effect of thrombus-growth suppression by US irradiation at 500 kHz in a 37°C water bath. The US acoustic intensity was set at or below 0.72 W/cm2, which is the maximum allowed for noninvasive acoustic irradiation. Low-intensity US irradiation of the thrombus-growth model resulted in a remarkable suppression of thrombus growth (100.22 ± 10.1 mg vs. 50.22 ± 5.3 mg, p < 0.0001), and the clot-growth inhibition depended logarithmically on acoustic intensity. Thrombus growth can be suppressed by low-intensity US irradiation, opening a new way to combat vascular reocclusion after rt-PA treatment of acute ischemic stroke.

Near-infrared phosphorescent carbon dots for sonodynamic precision tumor therapy

Theranostic sonosensitizers with combined sonodynamic and near infrared (NIR) imaging modes are required for imaging guided sonodynamic therapy (SDT). It is challenging, however, to realize a single material that is simultaneously endowed with both NIR emitting and sonodynamic activities. Herein, we report the design of a class of NIR-emitting sonosensitizers from a NIR phosphorescent carbon dot (CD) material with a narrow bandgap (1.62 eV) and long-lived excited triplet states (11.4 μs), two of which can enhance SDT as thermodynamically and dynamically favorable factors under low-intensity ultrasound irradiation, respectively. The NIR-phosphorescent CDs are identified as bipolar quantum dots containing both p- and n-type surface functionalization regions that can drive spatial separation of e−–h+ pairs and fast transfer to reaction sites. Importantly, the cancer-specific targeting and high-level intratumor enrichment of the theranostic CDs are achieved by cancer cell membrane encapsulation for precision SDT with complete eradication of solid tumors by single injection and single irradiation. These results will open up a promising approach to engineer phosphorescent materials with long-lived triplet excited states for sonodynamic precision tumor therapy.

Specific-Tuning Band Structure in Hetero-Semiconductor Nanorods to Match with Reduction of Oxygen Molecules for Low-Intensity Yet Highly Effective Sonodynamic/Hole Therapy of Tumors.

Sonosensitizers-assisted sonodynamic therapy (SDT) has been emerging as a promising treatment for cancers, and yet few specific regulations of band structure of sonosensitizers have been reported in relation to oxygen in tissues. Herein, by a gradient doping technique to modulate the band structure of hetero-semiconductor nanorods, it is found that the reduction potential of band-edge is very critical to reactive oxygen species (ROS) production under low-intensity ultrasound (US) irradiation and particularly, when aligned with the reduction of oxygen, ROS generation is found to be most significantly enhanced. Withal, US-generated oxidation holes are found to be effective in consuming overexpressed glutathione in tumor lesions, which amplifies cellular oxidative stress and finally induces tumor cell death. Moreover, the intrinsic fluorescence property of semiconductors provides imaging capability to illumine tumor area and guide the SDT process. This study demonstrates that the reduction potential state of sonosensitizers is of crucial importance in ROS generation and the proposed reduction potential-tailored hetero-semiconductor nanorods materialize low-intensity US irradiation yet highly effective SDT and synergetic hole therapy of tumors with imaging guidance and reduced radiation injury.

Ultrasound-Enhanced Reactive Oxygen Species Responsive Charge-Reversal Polymeric Nanocarriers for Efficient Pancreatic Cancer Gene Delivery.

Inefficient intracellular gene release and transfection limit nonviral gene delivery applications in cancer therapy. Reactive oxygen species (ROS) responsive nonviral gene delivery is the most widely explored strategy for such applications, yet the development of fast and safe ROS responsive nanocarriers proves to be a challenge because of the intracellular chemical equilibrium of high ROS and glutathione levels. Here, we report an ultrasound-enhanced ROS responsive charge-reversal polymeric nanocarrier (BTIL) for fast and efficient pancreatic cancer gene delivery. The BTIL is composed of B-PDEAEA/DNA polyplex-based cores and IR780-loaded liposome coatings. The IR780 is able to produce an excess of ROS under low intensity ultrasound irradiation, thus disequilibrating the chemical equilibrium of ROS and glutathione, and promoting the ROS-responsive positive-to-negative charge-reversal of the B-PDEAEA polymer. This charge conversion results in fast polyplex dissociation and intracellular gene release, inducing efficient gene transfection and cancer cell apoptosis. Moreover, following the intravenous administration, BTIL maintains a stable and long circulation in the bloodstream, achieves orthotopic pancreatic ductal adenocarcinoma distribution, and exhibits potent antitumor activity with negligible side effects. Our results reveal the proposed strategy to be both promising and universal for the development of fast and safe ROS responsive nonviral gene delivery in cancer therapy.

Intrinsic nucleus-targeted ultra-small metal\u2013organic framework for the type I sonodynamic treatment of orthotopic pancreatic carcinoma

BackgroundSonodynamic therapy (SDT) strategies exhibit a high tissue penetration depth and can achieve therapeutic efficacy by facilitating the intertumoral release of reactive oxygen species (ROS) with a short lifespan and limited diffusion capabilities. The majority of SDT systems developed to date are of the highly O2-dependent type II variety, limiting their therapeutic utility in pancreatic cancer and other hypoxic solid tumor types.ResultsHerein, a nucleus-targeted ultra-small Ti-tetrakis(4-carboxyphenyl)porphyrin (TCPP) metal–organic framework (MOF) platform was synthesized and shown to be an effective mediator of SDT. This MOF was capable of generating large quantities of ROS in an oxygen-independent manner in response to low-intensity ultrasound (US) irradiation (0.5 W cm−2), thereby facilitating both type I and type II SDT. This approach thus holds great promise for the treatment of highly hypoxic orthotopic pancreatic carcinoma solid tumors. This Ti-TCPP MOF was able to induce in vitro cellular apoptosis by directly destroying DNA and inducing S phase cell cycle arrest following US irradiation. The prolonged circulation, high intratumoral accumulation, and nucleus-targeting attributes of these MOF preparations significantly also served to significantly inhibit orthotopic pancreatic tumor growth and prolong the survival of tumor-bearing mice following Ti-TCPP + US treatment. Moreover, this Ti-TCPP MOF was almost completely cleared from mice within 7 days of treatment, and no apparent treatment-associated toxicity was observed.ConclusionThe nucleus-targeted ultra-small Ti-TCPP MOF developed herein represents an effective approach to the enhanced SDT treatment of tumors in response to low-intensity US irradiation.Graphic abstract

Concise Nanoplatform of Phycocyanin Nanoparticle Loaded with Docetaxel for Synergetic Chemo-sonodynamic Antitumor Therapy.

Combined chemotherapy and sonodynamic therapy (chemo-SDT) based on the nanoplatform/nanocarrier is a potential antitumor strategy that has shown higher therapeutic efficacy than any monotherapy. Therefore, a safe and effective multifunctional system with a concise design and simple preparation process is urgently needed. In this work, by using a one-step cross-linking method, a multifunctional nanosystem, which employs phycocyanin nanoparticles (PCNPs) as a nanocarrier to deliver the chemotherapy drug docetaxel (DTX) and a nanosonosensitizer to generate reactive oxygen species (ROS), was prepared and evaluated (PCNP-DTX). Under low-intensity ultrasound irradiation, PCNP-DTX retained the ROS generation ability of phycocyanin and caused the destruction of mitochondrial potential. PCNP was also revealed to be an acidic and ultrasound-sensitive carrier with good biocompatibility. In addition to its cumulation behavior in tumors, PCNP can achieve tumor-targeted delivery and release of DTX. PCNP-DTX has also been proven to have a significant chemo-SDT synergy effect when low-intensity ultrasound was applied, showing enhanced antitumor activity both in vitro and in vivo. This study provides a concise yet promising nanoplatform based on the natural protein phycocyanin for achieving an effective, targeted, and synergetic chemo-SDT for antitumor therapy.

Intracranial Sonodynamic Therapy With 5-Aminolevulinic Acid and Sodium Fluorescein: Safety Study in a Porcine Model.

BackgroundSonodynamic therapy (SDT) is an emerging ultrasound-based treatment modality for malignant gliomas which combines ultrasound with sonosensitizers to produce a localized cytotoxic and modulatory effect. Tumor-specificity of the treatment is achieved by the selective extravasation and accumulation of sonosensitizers in the tumor-bearing regions. The aim of this study is to demonstrate the safety of low-intensity ultrasonic irradiation of healthy brain tissue after the administration of FDA-approved sonosensitizers used for SDT in experimental studies in an in vivo large animal model.MethodsIn vivo safety of fluorescein (Na-Fl)- and 5 aminolevulinic acid (5-ALA)-mediated low-intensity ultrasound irradiation of healthy brain parenchyma was assessed in two sets of four healthy swine brains, using the magnetic resonance imaging (MRI)-guided Insightec ExAblate 4000 220 kHz system. After administration of the sonosensitizers, a wide fronto-parietal craniotomy was performed in pig skulls to allow transmission of ultrasonic beams. Sonication was performed on different spots within the thalamus and periventricular white matter with continuous thermal monitoring. Sonication-related effects were investigated with MRI and histological analysis.ResultsPost-treatment MRI images acquired within one hour following the last sonication, on day one, and day seven did not visualize any sign of brain damage. On histopathology, no signs of necrosis or apoptosis attributable to the ultrasonic treatments were shown in target areas.ConclusionsThe results of the present study suggest that either Na-FL or 5-ALA-mediated sonodynamic therapies under MRI-guidance with the current acoustic parameters are safe towards healthy brain tissue in a large in vivo model. These results further support growing interest in clinical translation of sonodynamic therapy for intracranial gliomas and other brain tumors.

Ultrasound irradiation inhibits proliferation of cervical cancer cells by initiating endoplasmic reticulum stress-mediated apoptosis and triggering phosphorylation of JNK.

Cervical cancer is the 2nd most frequently diagnosed gynecological cancer. Therefore, it is clinically significant to discover an effective anti-cancer approach. This study aimed to investigate the effects of low-intensity ultrasound irradiation (USI) on cervical cancer cells and associated mechanisms of cell death. Normal human cervical HaCaT cells and cervical cancer cell lines C33A, Hela and Siha were cultured and γ-rays applied at a dosage of 2.0 Gy/min. The MTT assay was then used to assess viability (proliferation) of HaCaT, C33A, Hela, and Siha cells. Small interfering RNA (siRNA) sequences that silence the glucose-related protein (GRP78) gene were synthesized. Structural changes to cells exposed to USI were observed with scanning electron microscopy. Immunocytochemistry and western blotting were utilized to examine GRP78, C/EBP-homologous protein (CHOP), phosphorylated JNK (p-JNK), and caspase-12 expression in cervical cancer cells. Ultrasound irradiation reduced the viability of cervical cancer cells and increased apoptosis, compared to untreated tumor cells (p < 0.05). This effect was not apparent on HaCaT cells. Ultrasound irradiation also induced formation of apoptotic bodies compared to untreated tumor cells (p < 0.05), and activated endoplasmic reticulum (ER) stress-associated apoptosis compared to untreated tumor cells (p < 0.05), by triggering GRP78, CHOP and caspase-12 expression. Moreover, USI triggered ER stress by upregulating GRP78 expression. Remarkably, USI triggered phosphorylation of JNK compared to untreated tumor cells (p < 0.05). Ultrasound irradiation initiated phosphorylation of JNK by increasing GRP78 expression. Silencing of GRP78 further enhanced the effect of USI on tumor cells. Ultrasound irradiation significantly inhibited proliferation and induced apoptosis of cervical cancer cells by initiating ER stress associated with apoptosis signaling pathways and triggering phosphorylation of JNK.

Endoleak Detection after Endovascular Aortic Aneurysm Repair Using Ultrasound Based on Nanoscale Bubble Contrast Agents and Their Effects on Vascular Smooth Muscle Cell Proliferation and Migration

Abdominal aortic aneurysm (AAA) is the most common vascular disease that causes disability and death. Its morbidity is relatively subtle, and the mortality rate is high. Clinically, endovascular aortic aneurysm repair (EVAR) has gradually become the primary treatment of AAA due to its unique advantages such as low trauma and low incidence of short-term complications. However, the outcome of EVAR is greatly compromised by the possible occurrence of endoleaks. Contrast-enhanced ultrasound (CEUS) is a promising alternative technique to detect endoleaks following EVAR due to lack of exposure to ionizing radiation. Traditional ultrasound contrast agents with an overlarge size (microscale) leading to reluctant accumulation in target organs and instability trigger the requirement of nanoscale contrast agents that enter tumor tissues through the enhanced permeability and retention effect. In this study, we used ultrasound based on nanoscale bubble contrast agents to evaluate endoleak detection after endovascular aortic aneurysm repair and analyzed the effects of nanoscale bubble contrast agents on vascular smooth muscle cell (VSMC) proliferation and migration. Among 52 AAA patients a month following EVAR, there were 16 cases of endoleaks after EVAR detected by nanobubble contrast-enhanced ultrasound, including 6 cases of type I endoleak (1 case of type Ia endoleak and 5 cases of type Ib endoleak), 7 cases of type II endoleak, and 3 cases of type III endoleak; there were 12 cases of endoleak after EVAR detected by computed tomography angiography (CTA), including 6 cases of type I endoleak (1 case of type Ia and 5 cases of type Ib), 5 cases of type II endoleak, and 1 case of type III endoleak. Six months after EVAR, 3 cases of type III endoleak were detected by both nanobubble contrast-enhanced ultrasound and CTA. Vascular smooth muscle cells (VSMCs) used for in vitro experiments were subjected to ultrasound irradiation and platelet-derived growth factor (PDGF) treatment with or without the addition of nanobubble contrast agents. After high-intensity and long-term irradiation (0.75 W/cm2 and 1 W/cm2 irradiation for 120 s and 150 s, respectively) by ultrasound with or without the addition of nanobubble contrast agents, PDGF-induced VSMC migration was inhibited ( P &lt; 0.01 ). Low-intensity and short-term ultrasound irradiation did not differ PDGF-induced VSMC migration ( P &gt; 0.05 ), but 0.5 W/cm2 and 90 s ultrasound irradiation could significantly inhibit PDGF-induced VSMC migration without the addition of nanobubble contrast agents ( P &lt; 0.05 ). When VSMCs were irradiated at 1, 0.75, 0.5, and 0.35 W/cm2 for 30 s to 150 s, ultrasound irradiation with or without the addition of nanobubble contrast agents remarkably reduced PDGF-induced VSMC proliferation, as evidenced by reduced OD values ( P &lt; 0.05 ). In conclusion, ultrasound based on nanoscale bubble contrast agents is an effective alternative detection method for the occurrence of AAA patients who are not suitable for CTA.

Enhancement of Anammox performances in an ABR at normal temperature by the low-intensity ultrasonic irradiation

A lab-scale ultrasound enhancing Anammox reactor (ABRU) was established and irradiated once a week by ultrasound with the optimal parameter (frequency of 25.0 kHz, intensity of 1.00 W cm−2 and exposure time of 36.0 s) obtained by response surface methodology (RSM). ABRU and the controlled Anammox reactor (ABRC) without ultrasonic treatment were operated in parallel. The start-up time of Anammox process in ABRU (59 d) was shorter than that in ABRC (69 d). At the end of the nitrogen load-enhancing period, NLR (0.500 kg N m−3 d−1) and NRR (0.430 kg N m−3 d−1) in ABRU were both higher than NLR (0.400 kg N m−3 d−1) and NRR (0.333 kg N m−3 d−1) in ABRC. The results of RTQ-PCR demonstrated that the specific low-intensity ultrasound irradiation improved the enrichment levels of AnAOB in mature sludge. SEM images and the observation of the macroscopic morphology of mature sludge showed that the ultrasound irradiation strengthened the formation of Anammox granular sludge, thereby improved the interception capacity and impact load resistance of the reactor, and enhanced the nitrogen removal performance in ABRU. The ultrasonic enhanced Anammox reactor based on an ABR with the optimal parameters can promote the rapid start-up and efficient and stable operation of the Anammox process at normal temperature (around 25.0 °C).

The Effect of Material Surface Microstructure on the Enhancement of Bone-Bonding Ability of a Hydroxyapatite-Implant by Low-Intensity Pulsed Ultrasound (LIPUS)

Excellent firm bonding between the biomaterials and bone tissue (osseointegration and osteo-conductivity) has been desired for the stability in vivo of dental implants and artificial joints. Much has been learned about this concept, which has led to significant improvements in the design and surface modification of implants in the field of implant dentistry, orthopedic surgery. We have already reported that low-intensity pulsed ultrasound (LIPUS) irradiation can accelerate the bone bonding ability of the bio-conductive materials such as bioactive titanium and hydroxyapatite implant. However, it is still unclear whether the LIPUS could have same effect to different types of the bioactive-materials. Therefore, in this study, the differences of bone-like hydroxyapatite formation on some kind of hydroxyapatite surface in simulated body fluid (SBF) under the LIPUS irradiation were investigated. Two kinds of hydroxyapatite samples immersed in SBF was exposed to ultrasound waves, the bone-like apatite on the surface was analyzed by Scanning electron microscopy and X-ray diffraction. As a result, the enhancement of hydroxyapatite formation on the surface by LIPUS was confirmed, the initial epitaxial nucleation and crystal growth of apatite depended on crystal structure of the surface of matrix materials.

Effect of low intensity pulsed ultrasound on osteoclast differentiation

ABSTRACT Purpose For many years, people have attempted to identify ways of efficiently moving teeth in orthodontic therapy to reduce harmful effects. In this study, we investigate whether the non-surgical method of low-intensity pulsed ultrasound (LIPUS) irradiation affects osteoclast differentiation in vitro. Materials and Methods RAW264 cells were stimulated with RANKL and U0126, and LIPUS irradiation was performed using different ultrasonic outputs, irradiation times, and number of irradiations. Assessments used TRAP staining, TRAP quantitative assays, and western blot analysis. Results LIPUS irradiation significantly increased osteoclast differentiation rates of RAW264 cells. The rates were significantly higher in the three-time irradiation group compared with the single irradiation group. However, significant differences were not observed between the ultrasonic output. TRAP quantitative assay results showed significantly increased osteoclast differentiation rates with increased irradiation time, however, only in the single irradiation group. Conclusion These results suggest that an increased number of LIPUS irradiations may improve its effectiveness in orthodontic therapy.

Development of a Composite of Polypyrrole-Coated Carbon Nanotubes as a Sonosensitizer for Treatment of Melanoma Cancer Under Multi-Step Ultrasound Irradiation

Sonodynamic therapy (SDT) has established a novel route for treating solid cancers. Low-intensity ultrasound irradiation accompanied by a sonosensitizer has revealed remarkable advantages for cancer therapy such as targeted uptake, access to deeper tumors, insignificant side effects and invasiveness, compared with other therapeutic methods. In this study, we scrutinized synthesis and characterization of a polypyrrole-coated multi-walled carbon nanotubes composite (PPy@MWCNTs). PPy@MWCNTs can absorb ultrasound irradiation by both of its components, and it was introduced as a new sonosensitizer. The composite was characterized by field emission scanning electron microscopy (FESEM), and its ability to temperature elevation was explored. FESEM images revealed that PPy@MWCNTs comprised nanotubes of 36.3 ± 5.1 nm in diameter with up to several micrometer in length. Ultrasound irradiation at 1 MHz and 1.0 W cm−2 for 60 s in four steps led to an efficient SDT in vitro (16.3 ± 2.8°C temperature increment for 250 μg mL−1 of PPy@MWCNTs), in C540 (B16/F10) cell line and a melanoma tumor model in male balb/c mice. In vitro examinations revealed that PPy@MWCNTs represented a concentration-dependent cytotoxicity on multi-step ultrasound irradiation (a cell viability of 8.9% for 250 μg mL−1 of PPy@MWCNTs). Histologic analyses and tumor volume decrement after 10 d revealed detrimental SDT effects of PPy@MWCNTs on tumors (75% necrosis and 50% decrement in tumor volume). Thermal effects and reactive oxygen species generation were the reasons of the working function of PPy@MWCNTs in SDT.

Low-intensity ultrasound radiation increases exosome yield for efficient drug delivery

Exosomes are emerging as a promising drug delivery vehicle, while the low yield from the cell culture medium restricts their potential application. Exploring strategies boosting the yields would be of significant importance. In this study, we aimed to explore whether low intensity ultrasound (LIUS) irradiation could booster the exosome yield, while having no significant effects on the characteristics. Treatment of LIUS at 0.5 w/cm2 60 min significantly promotes exosomes secretion in A2780 cells, an ovary cancer cell model used to produce exosomes. Moreover, the resultant exosomes had no significant change in morphology, size, and in vivo distribution. Mechanistical study further suggest that LIUS boosts exosome secretion possibly via promoting the expression of exosome biosynthesis/secretion-related genes. Taken together, our data indicate that LIUS could promote exosome biosynthesis, which could be an effective method to increase exosome yield for drug delivery.

Enhanced co-production of pectinase, cellulase and xylanase enzymes from Bacillus subtilis ABDR01 upon ultrasonic irradiation

The effect of low-intensity ultrasound irradiation was studied to improve the co-production for pectinase, cellulase, and xylanase enzymes using Bacillus subtilis ABDR01. Different parameters such as ultrasonic irradiation at the different growth phases of the bacterial strain, ultrasound power, irradiation duration, and irradiation duty cycle were assessed. Sonication with 90 W ultrasound power, 25 kHz frequency with 70 % duty cycle for 5 min at 6 h of bacterial growth phase gave the maximum productions of 87.82 U/ mL pectinase 22.17 U/ mL cellulase and 137.95 U/ mL xylanase respectively. The enzyme activity of pectinase, cellulase, and xylanase was enhanced by about 38.15 %, 53.77 %, and 24.59 %, respectively, compared to non-sonicated control cultivation. This optimized low-frequency ultrasound irradiation to bacterial cells enhanced the nutrient uptake rate and increased the cell wall permeability, which results in higher enzyme productivity. Our results signify the effectiveness of low-frequency ultrasound irradiation for improved enzyme yields and hyperactivation during microbial fermentation.

Evaluation of the Theranostic Potential of Perfluorohexane-Based Acoustic Nanodroplets.

In this study, we have prepared perfluorohexane (PFH)-based acoustic nanodroplets (PFH-NDs) and evaluated their theranostic characteristics. Nile Red (NR) was incorporated into PFH-NDs as a model of hydrophobic drugs (NR-PFH-NDs). The mean particle diameters of PFH-NDs and NR-PFH-NDs were 205 ± 1.8 nm and 346.3 ± 6 nm, respectively. There was no significant PFH leakage from PFH-NDs during 90 min incubation at 37°C in the presence of 10% rat serum. The in vitro ultrasonography showed that the phase transition of PFH-NDs from liquid droplets to gassed bubbles could be induced by therapeutic low-intensity ultrasound with a frequency of 1 MHz and an intensity of 5 W/cm2. Irradiation of ultrasound in combination with NR-PFH-NDs enhanced uptake of NR in murine adenocarcinoma cells (C26). After intravenous injection of PFH-NDs to mice, PFH gradually disappeared from blood circulation with an elimination half-life of 43.3 min. Intravenous injection of PFH-NDs also resulted in significant contrast enhancement in the mouse carotid artery upon therapeutic low-intensity ultrasound irradiation. These results suggest the potential of PFH-NDs as a novel contrast agent for further theranostic applications.

Echographic and physical characterization of albumin-stabilized nanobubbles

There has been increasing interest in using nanobubbles (NBs) for ultrasound mediated drug delivery as well as for ultrasound imaging. Albumin NBs are especially attractive for its potential of becoming a versatile platform for drug carriers and molecular targeted therapy agents. However, physical characterization of NBs is generally considered to be difficult due to various technical issues, such as concentration limitations, nanoparticle contamination, etc. In the present study, we measured the size distribution, concentration and weight density of albumin stabilized NBs by means of multiple nanoscale measurement modalities. Laser nanoparticle tracking analysis, multicolor flow cytometry, resonance mass evaluation showed consistent measurement results of the NBs with low mass weight density and diameter size ranging from 100 nm to 400 nm. Furthermore, the NB solution showed excellent images by high frequency ultrasound (30–50 MHz) in flow model acoustic phantoms. The NBs also induced acute cell disruption by low intensity ultrasound (0.8 W/cm2) irradiation. We successfully fabricated and characterized albumin stabilized NBs which could serve as an effective platform for future theranositic agents.