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Neuromodulation by ultrasound (US) has recently drawn considerable attention due to its great advantages in noninvasiveness, high penetrability across the skull and highly focusable acoustic energy. However, the mechanisms and safety from US irradiation still remain less understood. Recently, documents revealed Piezo1, a mechanosensitive cation channel, plays key role in converting mechanical stimuli from US through its trimeric propeller-like structure. Here, we developed a Piezo1-targeted microbubble (PTMB) which can bind to the extracellular domains of Piezo1 channel. Due to the higher responsiveness of bubbles to mechanical stimuli from US, significantly lower US energy for these PTMB-binding cells may be needed to open these mechanosensitive channels. Our results showed US energy at 0.03 MPa of peak negative pressure can achieve an equivalent level of cytoplasmic Ca2+ transients which generally needs 0.17 MPa US intensity for the control cells. Cytoplasmic Ca2+ elevations were greatly reduced by chelating extracellular calcium ions or using the cationic ion channel inhibitors, confirming that US-mediated calcium influx are dependent on the Piezo1 channels. No bubble destruction and obvious temperature increase were observed during the US exposure, indicating cavitation and heating effects hardly participate in the process of Ca2+ transients. In conclusion, our study provides a novel strategy to sensitize the response of nerve cells to US stimulation, which makes it safer application for US-mediated neuromodulation in the future.

Manxiang Wu,1,* Zhuqing Song,2,* Shiyu Zhang,1 Qing Dan,1 Caiyun Tang,3 Chao Peng,1 Yu Liang,1 Li Zhang,1 Hao Wang,4 Yingjia Li1 1Department of Medicine Ultrasonics, Nanfang Hospital, Southern Medical University, Guangzhou, People’s Republic of China; 2Department of Breast Surgery, Peking University Shenzhen Hospital, Shenzhen, People’s Republic of China; 3Pharmaceutical Analysis Department, College of Pharmacy, Jiamusi University, Jiamusi, People’s Republic of China; 4Department of Neurosurgery, Shenzhen People‘s Hospital, The Second Clinical Medical College of Jinan University, Shenzhen, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yingjia LiDepartment of Medicine Ultrasonics, Nanfang Hospital, Southern Medical University, No. 1023-1063, Sha Tai Nan Road, Baiyun District, Guangzhou 510515, People’s Republic of ChinaTel +86 20 6164200Email lyjia@smu.edu.cnHao WangDepartment of Neurosurgery, Shenzhen People’s Hospital, The Second Clinical Medical College of Jinan University, No.1017 Dongmen North Road, Luohu District, Shenzhen 518020, People’s Republic of ChinaTel +86 755 22948200Email hwmai@sina.comBackground: Ultrasound-targeted microbubble destruction (UTMD) has been shown to be a promising noninvasive technique to change the tumor circulation, thus providing a potential method to increase reactive oxygen species (ROS) levels in tumors by inducing tumor tissue ischemia-reperfusion (IR). In this study, we investigated the feasibility of local tumor IR through UTMD to enhance the anti-tumor efficacy of doxorubicin (DOX) chemotherapy.Methods: UTMD was used to induce local tumor IR. After the major blood supply of the tumor was restored, DOX was intravenously injected into the tumor-bearing mice. The superoxide dismutase (SOD) and catalase (CAT) activity and ROS levels were examined, and the anti-tumor efficacy was evaluated.Results: UTMD blocked the circulation to the tumor for 30 mins. Slow reperfusion began to occur after 30 mins, and major blood supply was restored after 1 hr. The blood perfusion of the tumor completely recovered at 2 hrs. The activity of SOD in the tumors was significantly decreased at 2 hrs and 1 day after IR treatment with or without DOX treatment. The CAT activity showed no obvious changes at 2 hrs after IR treatment, whereas a significant decrease was found after 1 day in both the IR and DOX/IR groups. Moreover, higher levels of ROS were produced in the IR group and IR/DOX group. In vivo anti-tumor study indicated that the local tumor IR strategy may significantly enhance the anti-tumor efficacy of DOX chemotherapy.Conclusion: UTMD provides a novel, simple and non-invasive technique for tumor IR. In combination with chemotherapy, UTMD may have high great potential to improve the anti-tumor efficacy of chemotherapeutic drugs.Keywords: ischemia-reperfusion, ultrasound targeted microbubble destruction, breast tumor, doxorubicin, combined treatment

The differentiation of benign and malignant tumors is of great significance for the preliminary evaluation of biological behaviors and prognosis of tumors prior to surgery or other interventions (1). Histopathological examination of the tumor biopsy samples serves as the gold standard for confirming the degree of malignancy of tumors. However, it is desirable and valuable to explore noninvasive imaging approaches to obtain diagnostic information at the earliest possible time points and without biopsy. When compared with other imaging modalities, ultrasound offers many advantages. It is safe, sensitive and portable. It offers a lower cost, yet also provides the features of real-time imaging and deep tissue penetration. Traditional ultrasound imaging technologies include B-mode-based grayscale ultrasonography, blood-flow-based color Doppler flow imaging (CDFI) and stiffness-based elastography. These techniques reflect local anatomy and can provide precursory information on the benign and malignant status of tumors (2,3). For example, the representative grayscale ultrasonography of malignant neoplasms is considered to be hypoechoic in grey scale, with fuzzy boundary often accompanied by microcalcification (4). CDFI is generally used to determine the benign vs. malignant tumor status from the blood vessel density and blood flow spectrum data (5,6). Contrast-enhanced ultrasound (CEUS) is capable of assessing the blood flow in the lesions through perfusion imaging of small capillary blood vessels (7,8). To some degree, all these methods provide diagnostic information on the benign or malignant status of the interrogated lesions. However, these ultrasound techniques mostly reflect the characteristics of tumor anatomy. During the past 20 years, ultrasound elastography has developed as a supplement to traditional ultrasound technology for differentiation of benign and malignant tumors, especially in superficial organs (9). Based on the heterogeneity of stiffness between different tumor tissues, ultrasound elastography can distinguish between benign and malignant tumors by detecting the modulus of elasticity (10). Studies have confirmed that, compared with conventional ultrasonography, ultrasound elastography has better specificity and accuracy in differentiating benign from malignant breast tumors (11,12). Nevertheless, ultrasound elastography has limitations in precise tumor diagnosis. The results of ultrasound elastography were easily affected by the skills of the operators and the location of the lesion, which might cause false positive results and reduce the diagnosis accuracy (13). Therefore, it is very important to develop novel ultrasound imaging technology to acquire functional information, especially the information on the tumor status at the molecular level, which is currently only available from invasive techniques, such as biopsy and histology. Fortunately, ultrasound technology has emerged with an exciting molecular imaging potential in tumor diagnosis. Ultrasound molecular imaging with targeted probes requires specific targeting to the receptors overexpressed on the angiogenic blood vessels. Such targeted contrast agents are administered intravenously, and accumulate in the vasculature in the areas of disease (14). Therefore, microbubbles, the most popular ultrasound contrast agents, need to be functionalized with appropriate ligands that have high affinity to the target vasculature biomarkers of disease, and allow specific binding and retention of these particles on the target vessel surface, despite the dislodging action of blood flow. Numerous targeting ligands, including antibodies, antibody fragments, peptides, and carbohydrates have been applied to construct targeted microbubble probes (15). By detecting the signals derived from the retained microbubbles in the target regions, ultrasound molecular imaging can determine the expression level of molecules and visualize biomarker status in situ. Multiple studies in vivo have demonstrated the diagnostic utility of ultrasound molecular imaging for the detection of inflammation, atherosclerosis and tumor angiogenesis in animal studies (16-19).

For extreme ultraviolet (EUV) radiation and soft X-rays, real part of the refractive indices of all materials are very close to unity, coupled with high absorption, makes the realization of high-reflective mirrors (just like visible and infrared light) impossible. Multilayer is a nano-structure, alternating of low- and high-Z materials in a periodic way, which can greatly enhance the reflectivity via the interference of light reflected from interfaces, like crystal optics. Reflective mirrors, polarization elements, monochromators, etc, can be made basing on multi-layer structures. Zone plate is a powerful tool to focus the light beam for EUV and soft X-ray into nanometer scale, which is produced by electron beam etching method. However, for hard X-ray, the zone plate will has smaller width of outmost layer and larger aspect ratio, which is difficult to realize. Multilayer Laue lens (MLL) is a promising method to overcome these limitations. MLL is a novel linear zone plate which is produced by depositing the depth-graded multilayer, according to the zone plate law reversely, on flat substrate and then slicing and polishing it to an ideal aspect ratio. In this paper, some recent development of multilayer optics for EUV and X-ray regions in IPOE will be introduced.

Interfacial structure of Mg/SiC multilayers as extreme ultra-violet reflectors was studied along with Mg/Si and Mg/C multilayers by means of x-ray reflectometry, x-ray diffraction, x-ray photoemission spectroscopy, and transmission electron microscopy. The interfacial diffusion in the Mg/SiC multilayer is found asymmetrical as the interlayers formed at SiC-on-Mg interfaces (2.5 nm) are much thicker than those at Mg-on-SiC interfaces (1.0 nm). Contrary asymmetry is found in the Mg/Si and Mg/C multilayers. An explanation of this phenomenon is suggested based on the investigation results. Our findings may result in improved reflectance of Mg/SiC multilayers by inserting diffusion barriers at the more diffused interfaces.