BackgroundPhotoacoustic imaging (PA) with high spatial resolution has great potential as desired monitoring means in the high intensity focused ultrasound (HIFU) surgery of tumor. However, its penetration depth in the tissue does not meet the clinical needs. Nanomedicine provides a new opportunity for PA imaging to guide HIFU surgery. Our studies found that hypoxic heterogeneity of tumor was effectively reversed by HIFU. MethodsHerein, speci c metal-organic framework nanosystem, constructed by coordination of banoxantrone (AQ4N) and Mn 2+ , is designed based on HIFU to reverse hypoxic heterogeneity of tumor. ResultsIt could provide exogenous light-absorbing substances, thus improves the penetrability of PA imaging signal through the deep tissue and achieves clearer PA imaging for guiding HIFU surgery. In turn, AQ4N, in the hypoxic homogenous environment of tumor provided by HIFU, is activated sequentially to speci cally treat the residual hypoxic tumor cells. ConclusionsThis strategy addresses the dissatisfaction of PA imaging-guided HIFU therapy and is promising for translation into a clinical combination regimen.
Background Research on the degradation of silk fibroin (SF) scaffolds in vivo lacks uniform and effective standards and experimental evaluation methods. This study aims to evaluate the application of ultrasound in assessing the degradation of SF scaffolds. Methods Two groups of three-dimensional regenerated SF scaffolds (3D RSFs) were implanted subcutaneously into the backs of Sprague-Dawley rats. B-mode ultrasound and hematoxylin and eosin (HE) staining were performed on days 3, 7, 14, 28, 56, 84, 112, 140, and 196. The cross-sectional areas for two groups of 3D RSFs that were obtained using these methods were semi-quantitatively analyzed and compared to evaluate the biodegradation of the implanted RSFs. Results The 3D RSFs in the SF-A group were wholly degraded at the 28th week after implantation. In contrast, the 3D RSFs in the SF-B group were completely degraded at the 16th week. Ultrasonic examination showed that the echoes of 3D RSFs in both groups gradually decreased with the increase of the implantation time. In the early stages of degradation, the echoes of the samples were higher than the echo of the muscle. In the middle of degeneration, the echoes were equal to the echo of the muscle. In the later stage, the echoes of the samples were lower than that of the muscle. The above changes in the SF-B group were earlier than those in the SF-A group. Semi-quantitative analysis of the cross-sectional areas detected using B-mode ultrasound revealed that the degradations of the two 3D RSF groups were significantly different. The degradation rate of the SF-B group was found to be higher than that of the SF-A group. This was consistent with the semi-quantitative detection results for HE staining. Regression analysis showed that the results of the B-mode ultrasound and HE staining were correlated in both groups, indicating that B-mode ultrasound is a reliable method to evaluate the SF scaffold degradation in vivo. Conclusions This study suggests that B-mode ultrasound can clearly display the implanted SF scaffolds non-invasively and monitor the degradation of the different SF scaffolds after implantation in living organisms in real-time.
Background Photoacoustic imaging (PA) with high spatial resolution has great potential as desired monitoring means in the high intensity focused ultrasound (HIFU) surgery of tumor. However, its penetration depth in the tissue does not meet the clinical needs. Nanomedicine provides a new opportunity for PA imaging to guide HIFU surgery. Our studies found that hypoxic heterogeneity of tumor was effectively reversed by HIFU. Methods Herein, specific metal-organic framework nanosystem, constructed by coordination of banoxantrone (AQ4N) and Mn2+, is designed based on HIFU to reverse hypoxic heterogeneity of tumor. Results It could provide exogenous light-absorbing substances, thus improves the penetrability of PA imaging signal through the deep tissue and achieves clearer PA imaging for guiding HIFU surgery. In turn, AQ4N, in the hypoxic homogenous environment of tumor provided by HIFU, is activated sequentially to specifically treat the residual hypoxic tumor cells. Conclusions This strategy addresses the dissatisfaction of PA imaging-guided HIFU therapy and is promising for translation into a clinical combination regimen.
Stacking two-dimensional materials into heterogeneous structures is an effective strategy to regulate their physical properties and enrich their applications in modern nanoelectronics. The electronic structure and optical properties of a new two-dimensional Janus Ga<sub>2</sub>SeTe/In<sub>2</sub>Se<sub>3</sub> heterojunction with four stacked configurations are investigated by first principles calculations. The heterojunction of the four configurations is an indirect band-gap semiconductor with a type II band structure, and the photoelectron donor and acceptor materials are determined by the polarization direction of two-dimensional In<sub>2</sub>Se<sub>3</sub>. The light absorption is up to 25% in the visible region, which is conducive to the effective utilization of the solar visible light. The biaxial strain can induce direct-indirect bandgap transition, and the applied electric field can effectively regulate the bandgap of heterogeneous structures. The bandgap of AA2 configuration increases monotonically from 0.195 eV to 0.714 eV, and that of AB2 configuration decreases monotonically from 0.859 eV to 0.058 eV. The bands of the heterojunction always maintain the type II structure under the two kinds of configurations. The heterojunctions under compressive strain show better light absorption capacity in the visible region with shorter wavelength. These results reveal the regulatory mechanism of the Janus Ga<sub>2</sub>SeTe/In<sub>2</sub>Se<sub>3</sub> van der Waals heterojunction electronic structure and provide theoretical guidance for the design of novel optoelectronic devices.
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