Focused ultrasound stimulation of infralimbic cortex attenuates reinstatement of methamphetamine-induced conditioned place preference in rats.

Methamphetamine (MA) use disorder poses significant challenges to both the affected individuals and society. Current non-drug therapies like transcranial direct-current stimulation and transcranial magnetic stimulation have limitations due to their invasive nature and limited reach to deeper brain areas. Transcranial focused ultrasound (FUS) is gaining attention as a noninvasive option with precise spatial targeting, able to affect deeper areas of the brain. This research focused on assessing the effectiveness of FUS in influencing the infralimbic cortex (IL) to prevent the recurrence of MA-seeking behavior, using the conditioned place preference (CPP) method in rats. The study involved twenty male Sprague-Dawley rats. Neuronal activation by FUS was first examined via electromyography (EMG). Rats received alternately with MA or saline, and confined to one of two distinctive compartments in a three compartment apparatus over a 4-day period. After CPP test, extinction, the first reinstatement, and extinction again, FUS was applied to IL prior to the second MA priming-induced reinstatement. Safety assessments were conducted through locomotor and histological function examinations. EMG data confirmed the effectiveness of FUS in activating neurons. Significant attenuation of reinstatement of MA CPP was found, along with successful targeting of the IL region, confirmed through acoustic field scanning, c-Fos immunohistochemistry, and Evans blue dye staining. No damage to brain tissue or impaired locomotor activity was observed. The results of the study indicate that applying FUS to the IL markedly reduced the recurrence of MA seeking behavior, without harming brain tissue or impairing motor skills. This suggests that FUS could be a promising method for treating MA use disorder, with the infralimbic cortex being an effective target for FUS in preventing MA relapse.

Application of Ultrasound to Enhancing Stem Cells Associated Therapies.

Pluripotent stem cell therapy exhibits self-renewal capacity and multi-directional differentiation potential and is considered an important regenerative approach for the treatment of several diseases. However, insufficient cell transplantation efficiency, uncontrollable differentiation, low cell viability, and difficult tracing limit its clinical applications and treatment outcome. Ultrasound (US) has mechanical, cavitation, and thermal effects that can produce different biological effects on organs, tissues, and cells. US can be combined with different US-responsive particles for enhanced physical-chemical stimulation and drug delivery. In the meantime, US also can provide a noninvasive and harmless imaging modality for deep tissue in vivo. An in-depth evaluation of the role and mechanism of action of US in stem cell therapy would enhance understanding of US and encourage research in this field. In this article, we comprehensively review progress in the application of US alone and combined with US-responsive particles for the promotion of proliferation, differentiation, migration, and in vivo detection of stem cells and the potential clinical applications.

Enhanced sonodynamic therapy by carbon dots-shelled microbubbles with focused ultrasound.

Sonodynamic therapy involving the non-invasive and local generation of lethal reactive oxygen species (ROS) via ultrasound (US) with sonosensitizers has been proposed as an emerging tumor therapy strategy. However, such therapy is usually associated with inertial cavitation and unnecessary damage to healthy tissue because current sonosensitizers have insufficient sensitivity to US. Here, we report the use of a new proposed sonosensitizer, carbon dots (C-dots), to assemble microbubbles with a gas core (C-dots MBs). As the C-dots were directly integrated into the MB shell, they could effectively absorb the energy of inertial cavitation and transfer it to ROS. Our results revealed the appearance of 1O2, •OH, and H2O2 after US irradiation of C-dots MBs. In in vitro experiments, treatment with C-dots MBs plus US induced lipid peroxidation, elevation of intracellular ROS, and apoptosis in 32.5%, 45.3%, and 50.1% of cells respectively. In an animal solid tumor model, treatment with C-dots MBs plus US resulted in a 3-fold and 2.5-fold increase in the proportion of ROS-damaged cells and apoptotic cells, respectively, compared to C-dots MBs alone. These results will pave the way for the design of novel multifunctional sonosensitizers for SDT tumor therapy.

Enhancing Doxorubicin Delivery in Solid Tumor by Superhydrophobic Amorphous Calcium Carbonate-Doxorubicin Silica Nanoparticles with Focused Ultrasound.

The current approach of delivering chemotherapy via pH-sensitive amorphous calcium carbonate-doxorubicin silica nanoparticles (ADS NPs) faces the challenge of insufficient drug dose due to drug instability within the bloodstream and poor tumor penetration. To overcome these long-standing obstacles, we proposed a superhydrophobic coating on the surface of the ADS NPs that could be easily modified via fluorination (ADSF NPs). The surface of fluorinated ADS NPs was further modified with a phospholipid layer to reduce aggregation and improve biocompatibility (ADSFL NPs). The contact angle and mean size of ADSFL NPs were 30.2 ± 4.4° and 353.1 ± 54.2 nm, respectively. The superhydrophobic layer generated interfacial nanobubbles on the outer shell of the NPs that reduced water-induced leakage of doxorubicin (DOX) sevenfold compared with the uncoated group and induced a cavitation effect upon ultrasound (US) sonication. Moreover, release of DOX from the ADSFL NPs could be triggered by US, and this release was further improved 1.6-fold in acidic aqueous conditions, indicating that the ADSFL NPs retained pH responsiveness. Enhanced sonography contrast and histological examination demonstrated that US could trigger cavitation activities from ADSFL NPs in vivo to induce vessel disruption and enhance the fluorescence intensity of DOX within the tumor region threefold under US imaging guidance compared with the ADSFL NPs-only group.

State-of-the-art of ultrasound-triggered drug delivery from ultrasound-responsive drug carriers.

INTRODUCTION: Delivering sufficient therapeutics at the target site without off-target effects is a major goal of drug delivery technology innovation. Among the established methods, ultrasound (US) with US-responsible carriers holds great promise and demonstrates on-demand delivery of a variety of functional substances with spatial precision of several millimeters in deep-seated tissues in animal models and humans. These properties have motivated several explorations of US with US responsible-responsible carriers as a modality for neuromodulation and the treatment of various diseases, such as stroke and cancer. AREAS COVERED: We briefly discuss three specific mechanisms that enhance in vivo drug delivery via US with US-responsible carriers: 1) permeabilizing cellular membrane, 2) increasing the permeability of vessels, and 3) promoting cellular endocytotic uptake. We then reviewed the state-of-the-art materials for US-triggered drug delivery, including conventional US contrast agents, and nanocarrier formulations, such as inorganic nanoparticles and gas vesicles. EXPERT OPINION: In this article, we summarized recent progress for each of US-responsible drug carrier, focusing on the routes of enhancing delivery and applications. The mechanisms of interaction between US-responsible carriers and US waves, such as cavitation, streaming, hyperthermia, and ROS, as well as how those interactions can improve drug release and cell/tissue uptake.

Overcoming Hypoxia-Induced Drug Resistance via Promotion of Drug Uptake and Reoxygenation by Acousto-Mechanical Oxygen Delivery.

Hypoxia-induced drug resistance (HDR) is a critical issue in cancer therapy. The presence of hypoxic tumor cells impedes drug uptake and reduces the cytotoxicity of chemotherapeutic drugs, leading to HDR and increasing the probability of tumor recurrence and metastasis. Microbubbles, which are used as an ultrasound contrast agent and drug/gas carrier, can locally deliver drugs/gas and produce an acousto-mechanical effect to enhance cell permeability under ultrasound sonication. The present study applied oxygen-loaded microbubbles (OMBs) to evaluate the mechanisms of overcoming HDR via promotion of drug uptake and reoxygenation. A hypoxic mouse prostate tumor cell model was established by hypoxic incubation for 4 h. After OMB treatment, the permeability of HDR cells was enhanced by 23 ± 5% and doxorubicin uptake was increased by 11 ± 7%. The 61 ± 14% reoxygenation of HDR cells increased the cytotoxicity of doxorubicin from 18 ± 4% to 58 ± 6%. In combination treatment with OMB and doxorubicin, the relative contributions of uptake promotion and reoxygenation towards overcoming HDR were 11 ± 7% and 28 ± 10%, respectively. Our study demonstrated that reoxygenation of hypoxic conditions is a critical mechanism in the inhibition of HDR and enhancing the outcome of OMB treatment.

Ultrasound-activated nanomaterials for sonodynamic cancer theranostics.

Despite intensive efforts to develop diagnostic and therapeutic tools, the successful treatment of cancer is still hampered by the obscure boundary between cancerous cells and normal cells, recurrence of the cancer, and the development of drug resistance during chemotherapy. In recent years, sonodynamic therapy (SDT), employing therapeutic ultrasound with sonosensitizers, has attracted attention as a potentially promising approach for cancer therapy. This review describes the current understanding of the mechanisms and the preclinical and clinical efficacy of SDT-based applications in tumors, providing an insight into the therapeutic potential offered by SDT. The limitations and future directions of this emerging treatment are also discussed.

Dynamic Ultrasound Assessment of Median Nerve Mobility Changes Following Corticosteroid Injection and Carpal Tunnel Release in Patients With Carpal Tunnel Syndrome.

Decreased median nerve (MN) mobility was found in patients with carpal tunnel syndrome (CTS) and was inversely associated with symptom severity. It is unclear whether MN mobility can be restored with interventions. This study compared the changes in MN mobility and clinical outcomes after interventions. Forty-six patients with CTS received an injection (n = 23) or surgery (n = 23). Clinical outcomes [Visual Analogue Scale; Boston Carpal Tunnel Questionnaire (BCTQ), which includes the Symptom Severity Scale and Functional Status Scale; median nerve cross-sectional area; and dynamic ultrasound MN mobility parameters (amplitude, and R2 value and curvature of the fitted curves of MN transverse sliding)] were assessed at baseline and 12 weeks after the interventions. At baseline, the BCTQ-Functional Status Scale and median nerve cross-sectional area showed significant inter-treatment differences. At 12 weeks, both treatments had significant improvements in BCTQ-Symptom Severity Scale and Visual Analogue Scale scores and median nerve cross-sectional area, but with greater improvements in BCTQ-Functional Status Scale scores observed in those who received surgery than in those who received injections. MN mobility was insignificantly affected by both treatments. The additional application of dynamic ultrasound evaluation may help to discriminate the severity of CTS initially; however, its prognostic value to predict clinical outcomes after interventions in patients with CTS is limited.

Sonogenetic-Based Neuromodulation for the Amelioration of Parkinson's Disease.

Sonogenetics is a promising strategy allowing the noninvasive and selective activation of targeted neurons in deep brain regions; nevertheless, its therapeutic outcome for neurodegeneration diseases that need long-term treatment remains to be verified. We previously enhanced the ultrasound (US) sensitivity of targeted cells by genetic modification with an engineered auditory-sensing protein, mPrestin (N7T, N308S). In this study, we expressed mPrestin in the dopaminergic neurons of the substantia nigra in Parkinson's disease (PD) mice and used 0.5 MHz US for repeated and localized brain stimulation. The mPrestin expression in dopaminergic neurons persisted for at least 56 days after a single shot of adeno-associated virus, suggesting that the period of expression was long enough for US treatment in mice. Compared to untreated mice, US stimulation ameliorated the dopaminergic neurodegeneration 10-fold and mitigated the PD symptoms of the mice 4-fold, suggesting that this sonogenetic strategy has the clinical potential to treat neurodegenerative diseases.

Ultrasonic technologies in imaging and drug delivery.

Ultrasonic technologies show great promise for diagnostic imaging and drug delivery in theranostic applications. The development of functional and molecular ultrasound imaging is based on the technical breakthrough of high frame-rate ultrasound. The evolution of shear wave elastography, high-frequency ultrasound imaging, ultrasound contrast imaging, and super-resolution blood flow imaging are described in this review. Recently, the therapeutic potential of the interaction of ultrasound with microbubble cavitation or droplet vaporization has become recognized. Microbubbles and phase-change droplets not only provide effective contrast media, but also show great therapeutic potential. Interaction with ultrasound induces unique and distinguishable biophysical features in microbubbles and droplets that promote drug loading and delivery. In particular, this approach demonstrates potential for central nervous system applications. Here, we systemically review the technological developments of theranostic ultrasound including novel ultrasound imaging techniques, the synergetic use of ultrasound with microbubbles and droplets, and microbubble/droplet drug-loading strategies for anticancer applications and disease modulation. These advancements have transformed ultrasound from a purely diagnostic utility into a promising theranostic tool.

Injection of hybrid 3D spheroids composed of podocytes, mesenchymal stem cells, and vascular endothelial cells into the renal cortex improves kidney function and replenishes glomerular podocytes.

Podocytes are highly differentiated epithelial cells that are crucial for maintaining the glomerular filtration barrier in the kidney. Podocyte injury followed by depletion is the major cause of pathological progression of kidney diseases. Although cell therapy has been considered a promising alternative approach to kidney transplantation for the treatment of kidney injury, the resultant therapeutic efficacy in terms of improved renal function is limited, possibly owing to significant loss of engrafted cells. Herein, hybrid three-dimensional (3D) cell spheroids composed of podocytes, mesenchymal stem cells, and vascular endothelial cells were designed to mimic the glomerular microenvironment and as a cell delivery vehicle to replenish the podocyte population by cell transplantation. After creating a native glomerulus-like condition, the expression of multiple genes encoding growth factors and basement membrane factors that are strongly associated with podocyte maturation and functionality was significantly enhanced. Our in vivo results demonstrated that intrarenal transplantation of podocytes in the form of hybrid 3D cell spheroids improved engraftment efficiency and replenished glomerular podocytes. Moreover, the proteinuria of the experimental mice with hypertensive nephropathy was effectively reduced. These data clearly demonstrated the potential of hybrid 3D cell spheroids for repairing injured kidneys.

Oscillatory behavior of microbubbles impacts efficacy of cellular drug delivery.

Drug-loaded microbubbles have been proven to be an effective strategy for non-invasive and local drug delivery when combined with ultrasound excitation for targeted drug release. Inertial cavitation is speculated to be a major mechanism for releasing drugs from drug-loaded microbubbles, but it results in lethal cellular pore damage that greatly limits its application. Thus, we investigated the cellular vesicle attachment and uptake to evaluate the efficiency of drug delivery by modulating the behaviors of targeted microbubble oscillation. The efficiency of vesicle attachment on the targeted cell membrane was 36.5 ± 15.9% and 3.8 ± 2.3% under stable and inertial cavitation, respectively. Further, stable cavitation enhanced cell permeability (26.8 ± 3.2%), maintained cell viability (90.8 ± 2.1%), and showed 7.9 ± 1.9-fold enhancement of in vivo vesicle release on tumor vessels. Therefore, our results reveal the ability to improve drug delivery via stable cavitation induced by targeted microbubbles. We propose that this strategy might be suitable for tissue repair or neuromodulation.

Improvement of light penetration in biological tissue using an ultrasound-induced heating tunnel.

The major obstacles of optical imaging and photothermal therapy in biomedical applications is the strong scattering of light within biological tissues resulting in light defocusing and limited penetration. In this study, we propose high intensity focused ultrasound (HIFU)-induced heating tunnel to reduce the photon scattering. To verify our idea, Monte Carlo simulation and intralipid-phantom experiments were conducted. The results show that the thermal effect created by HIFU could improve the light fluence at the targeted region by 3% in both simulation and phantom experiments. Owing to the fluence increase, similar results can also be found in the photoacoustic experiments. In conclusion, our proposed method shows a noninvasive way to increase the light delivery efficiency in turbid medium. It is expected that our finding has a potential for improving the focal light delivery in photoacoustic imaging and photothermal therapy.

Ultrasound with microbubbles improves memory, ameliorates pathology and modulates hippocampal proteomic changes in a triple transgenic mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disease manifested by cognitive impairment. As a unique approach to open the blood-brain barrier (BBB) noninvasively and temporarily, a growing number of studies showed that low-intensity focused ultrasound in combination with microbubbles (FUS/MB), in the absence of therapeutic agents, is capable of ameliorating amyloid or tau pathology, concurrent with improving memory deficits of AD animal models. However, the effects of FUS/MB on both the two pathologies simultaneously, as well as the memory behaviors, have not been reported so far. Methods: In this study, female triple transgenic AD (3×Tg-AD) mice at eight months of age with both amyloid-ß (Aß) deposits and tau phosphorylation were treated by repeated FUS/MB in the unilateral hippocampus twice per week for six weeks. The memory behaviors were investigated by the Y maze, the Morris water maze and the step-down passive avoidance test following repeated FUS/MB treatments. Afterwards, the involvement of Aß and tau pathology were assessed by immunohistochemical analysis. Neuronal health and phagocytosis of Aß deposits by microglia in the hippocampus were examined by confocal microscopy. Further, hippocampal proteomic alterations were analyzed by employing two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) combined with mass spectrometry. Results: The three independent memory tasks were indicative of evident learning and memory impairments in eight-month-old 3×Tg-AD mice, which developed intraneuronal Aß, extracellular diffuse Aß deposits and phosphorylated tau in the hippocampus and amygdala. Following repeated FUS/MB treatments, significant improvement in learning and memory ability of the 3×Tg-AD mice was achieved. Amelioration in both Aß deposits and phosphorylated tau in the sonicated hemisphere was induced in FUS/MB-treated 3×Tg-AD mice. Albeit without increase in neuron density, enhancement in axonal neurofilaments emerged from the FUS/MB treatment. Confocal microscopy revealed activated microglia engulfing Aß deposits in the FUS/MB-treated hippocampus. Further, proteomic analysis revealed 20 differentially expressed proteins, associated with glycolysis, neuron projection, mitochondrial pathways, metabolic process and ubiquitin binding etc., in the hippocampus between FUS/MB-treated and sham-treated 3×Tg-AD mice. Conclusions: Our findings reinforce the positive therapeutic effects on AD models with both Aß and tau pathology induced by FUS/MB-mediated BBB opening, further supporting the potential of this treatment regime for clinical applications.

Near Infrared-Activatable Platinum-Decorated Gold Nanostars for Synergistic Photothermal/Ferroptotic Therapy in Combating Cancer Drug Resistance.

Ferroptotic cell death results from glutathione peroxidase 4 (GPX4) inactivation and/or glutathione (GSH) depletion. Elevated GSH levels are often found in multidrug-resistant (MDR) tumor cells, reducing their sensitivity to chemotherapeutic drugs and the efficacy of treatment. MDR cells also acquire a dependency on GPX4, reducing their oxidative stress and promoting their survival. Therefore, the depletion of GSH and inactivation of GPX4 has the potential to be a superior treatment strategy for MDR tumors. Platinum-decorated gold nanostars (Pt-AuNS) are presented as a novel metal nanoprodrug for ferroptotic therapy against MDR tumors. Under dark conditions, the synthesized Pt-AuNS exhibit negligible levels of toxicity. Upon exposure of the Pt-AuNS to near-infrared (NIR) light, active metallic (Pt and Au) species are released, subsequently inducing cytotoxicity. The mechanism of action is attributed to GSH depletion and GPX4 inactivation, accumulating lipid hydroperoxides, which in turn leads to ferroptosis. In in vivo xenograft, the MDR cancer model confirmed the NIR light-activation of Pt-AuNS prodrugs, resulting in efficient ferroptotic therapeutic action against MDR tumors without long-term side effects. The findings lay the groundwork for using Pt-AuNS prodrugs responsive to NIR light as ferroptosis-inducing agents in chemo-resistant cancer cells and demonstrate their potential for use in future clinical applications.

Ultrasound in tumor immunotherapy: Current status and future developments.

Immunotherapy has considerable potential in eliminating cancers by activating the host's own immune system, while the thermal and mechanical effects of ultrasound have various applications in tumor therapy. Hyperthermia, ablation, histotripsy, and microbubble stable/inertial cavitation can alter the tumor microenvironment to enhance immunoactivation to inhibit tumor growth. Microbubble cavitation can increase vessel permeability and thereby improve the delivery of immune cells, cytokines, antigens, and antibodies to tumors. Violent microbubble cavitation can disrupt tumor cells and efficiently expose them to numerous antigens so as to promote the maturity of antigen-presenting cells and subsequent adaptive immune-cell activation. This review provides an overview and compares the mechanisms of ultrasound-induced immune modulation for peripheral and brain tumor therapy, even degenerative brain diseases therapy. The possibility of reversing tumors to an immunoactive microenvironment by utilizing the cavitation of microbubbles loaded with therapeutic gases is also proposed as another potential pathway for immunotherapy. Finally, we disuss the challenges and opportunities of ultrasound in immunotherapy for future development.

A preliminary study of Parkinson's gene therapy via sono-magnetic sensing gene vector for conquering extra/intracellular barriers in mice.

BACKGROUND: Non-virus genetic treatment for Parkinson's disease (PD) via plasmid glial cell-line derived neurotrophic factor (pGDNF) has shown potential for repairing damaged dopaminergic neurons. However, development of this gene therapy is largely hampered by the insufficient transfection efficiency as a result of the cell membrane, lysosome, and cytoskeleton meshwork. METHODS: In this study, we propose the use of polyethylenimine (PEI)-superparamagnetic iron oxide-plasmid DNA (pDNA)-loaded microbubbles (PSp-MBs) in conjunction with focused ultrasound (FUS) and two-step magnetic navigation to provide cavitation, proton sponge effect and magnetic effects to increase the efficiency of gene delivery. RESULTS: The gene transfection rate in the proposed system was 2.2-fold higher than that of the commercial agent (TransIT®-LT1). The transfection rate could be boosted ∼11%, ∼10%, and 6% by cavitation-magnetic hybrid enhanced cell membrane permeabilization, proton sponge effect, and magnetic-assisted cytoskeleton-reorganization, respectively. In vivo data suggested that effective gene delivery with this system results in a 3.2-fold increase in recovery of dopaminergic neurons and a 3.9-fold improvement in the motor behavior when compared to untreated genetic PD mice. CONCLUSIONS: We proposed that this novel FUS-magnetic hybrid gene delivery platform could be integrated with a variety of therapeutic genes for treating neurodegenerative diseases in the future.

Targeted delivery of engineered auditory sensing protein for ultrasound neuromodulation in the brain.

Sonogenetics is a promising approach for in vivo neuromodulation using ultrasound (US) to non-invasively stimulate cells in deep tissue. However, sonogenetics requires accurate transduction of US-responsive proteins into target cells. Here, we introduce a non-invasive and non-viral approach for intracerebral gene delivery. This approach utilizes temporary ultrasonic disruption of the blood-brain barrier (BBB) to transfect neurons at specific sites in the brain via DNA that encodes engineered US-responsive protein (murine Prestin (N7T, N308S))-loaded microbubbles (pPrestin-MBs). Prestin is a transmembrane protein that exists in the mammalian auditory system and functions as an electromechanical transducer. We further improved the US sensitivity of Prestin by introducing specific amino acid substitutions that frequently occur in sonar species into the mouse Prestin protein. We demonstrated this concept in mice using US with pPrestin-MBs to non-invasively modify and activate neurons within the brain for spatiotemporal neuromodulation. Method: MBs composed of cationic phospholipid and C3F8 loaded with mouse Prestin plasmid (pPrestin) via electrostatic interactions. The mean concentration and size of the pPrestin-MBs were (16.0 ± 0.2) × 109 MBs/mL and 1.1 ± 0.2 µm, respectively. SH-SY5Y neuron-like cells and C57BL mice were used in this study. We evaluated the gene transfection efficiency and BBB-opening region resulting from pPrestin-MBs with 1-MHz US (pressure = 0.1-0.5 MPa, cycle = 50-10000, pulse repetition frequency (PRF): 0.5-5 Hz, sonication time = 60 s) using green fluorescence protein (Venus) and Evans blue staining. Results: The maximum pPrestin expression with the highest cell viability occurred at a pressure of 0.5 MPa, cycle number of 5000, and PRF of 1 Hz. The cellular transfection rate with pPrestin-MBs and US was 20.2 ± 2.5%, which was 1.5-fold higher than that of commercial transfection agents (LT-1). In vivo data suggested that the most profound expression of pPrestin occurred at 2 days after performing pPrestin-MBs with US (0.5 MPa, 240 s sonication time). In addition, no server erythrocyte extravasations and apoptosis cells were observed at US-sonicated region. We further found that with 0.5-MHz US stimulation, cells with Prestin expression were 6-fold more likely to exhibit c-Fos staining than cells without Prestin expression. Conclusion: Successful activation of Prestin-expressing neurons suggests that this technology provides non-invasive and spatially precise selective modulation of one or multiple specific brain regions.

Characterization of limb lymphedema using the statistical analysis of ultrasound backscattering.

BACKGROUND: Lymphedema is a disease in which tissue swelling is caused by interstitial fluid retention in subcutaneous tissue. It is caused by a compromised lymphatic system. Lymphoscintigraphy is the current and primary modality used to assess lymphatic system dysfunction. Ultrasound elastography is a complementary tool used for evaluating the tissue stiffness of the lymphedematous limb. Tissue stiffness implies the existence of changes in tissue microstructures. However, ultrasound features related to tissue microstructures are neglected in clinical assessments of lymphedematous limbs. In this study, we aimed to evaluate the lymphedematous diagnostic values of ultrasound Nakagami and entropy imaging, which are, respectively, model- and nonmodel-based backscattered statistical analysis methods for scatterer characterization. METHODS: A total of 60 patients were recruited, and lymphoscintigraphy was used to score the patient's clinical severity of each of their limb lymphedema (0: normal; 1: partial lymphatic obstruction; and 2: total lymphatic obstruction). We performed ultrasound examinations to acquire ultrasound backscattered signals for B-mode, Nakagami, and entropy imaging. The envelope amplitude, Nakagami, and entropy values, as a function of the patients' lymphatic obstruction grades, were expressed in terms of their median and interquartile range (IQR). The values were then used in both an independent t test and a receiver operating characteristic (ROC) curve analysis. RESULTS: For each increase in a patient's score from 0 to 2, the envelope amplitude values were 405.44 (IQR: 238.72-488.17), 411.52 (IQR: 298.53-644.25), and 476.37 (IQR: 348.86-648.16), respectively. The Nakagami parameters were 0.16 (IQR: 0.14-0.22), 0.26 (IQR: 0.23-0.34), and 0.24 (IQR: 0.16-0.36), respectively, and the entropy values were 4.55 (IQR: 4.41-4.66), 4.86 (IQR: 4.78-4.99), and 4.87 (IQR: 4.81-4.97), respectively. The P values between the normal control and lymphedema groups obtained from B-mode and Nakagami analysis were larger than 0.05; whereas that of entropy imaging was smaller than 0.05. The areas under the ROC curve for B-mode, Nakagami, and entropy imaging were 0.64 (sensitivity: 70%; specificity: 47.5%), 0.75 (sensitivity: 70%; specificity: 75%), and 0.94 (sensitivity: 95%; specificity: 87.5%), respectively. CONCLUSIONS: The current findings demonstrated the diagnostic values of ultrasound Nakagami and entropy imaging techniques. In particular, the use of non-model-based entropy imaging enables for improved performance when characterizing limb lymphedema.

Superhydrophobic drug-loaded mesoporous silica nanoparticles capped with ß-cyclodextrin for ultrasound image-guided combined antivascular and chemo-sonodynamic therapy.

Interfacial nanobubbles (INBs) on a superhydrophobic surface has been proposed as a solid cavitation agent for enhancing inertial cavitation dose and ultrasound contrast imaging, but the dispersibility of superhydrophobic particles limits the biomedical application. For this study, we designed superhydrophobic mesoporous silica nanoparticles loaded with the anti-tumor drug Doxorubicin (FMSNs-Dox) for tumor therapy. The ß-cyclodextrin was used to cap the superhydrophobic surface of FMSNs-Dox to reduce aggregation without inhibiting the accumulation of INBs. The mean size and a contact angle of FMSNs-Dox was 217 ± 58 nm and 129 ± 3°, respectively. The INBs cavitation on the surface of FMSNs-Dox during ultrasound sonication disrupted tumor vessels to allow a large amount of drug penetrating and trapping within tumors. The reduced tumor perfusion, histological reactive oxygen species staining, and tumor inhibition demonstrated that FMSNs-Dox sonication combined anti-vascular, sonodynamic and chemical therapies in a simple platform. Moreover, the repeatability of INB cavitation by single-injection FMSNs-Dox with multiple ultrasound sonication provided intratumoral ultrasound contrast-enhanced imaging from day 1-9 (enhancement of 3.84 ± 0.47 dB). Therefore, the characteristics of FMSNs-Dox with slow biodegradation and acoustic-sensitivity presented intratumoral day-scaled lifetime to provide a probability of repeated combination therapy by single-injection.