Hypoxia in a solid tumor microenvironment (TME) can lead to the overexpression of hypoxia-inducible factor-1α (HIF-1α), which correlates to tumor metastasis. Reactive oxygen species (ROS) induced tumor cell apoptosis is becoming a promising method in tumor treatment. Currently, the ROS generating systems, e.g., photodynamic treatment and sonodynamic treatment, highly depend on oxygen (O 2 ) in the tumor microenvironment (TME). However, the level of O 2 in TME is too low to produce enough ROS. Herein, we developed an ultrasmall DSPE-PEG 2000 coated barium titanate nanoparticle (P-BTO) for tumor treatment based on ultrasound triggered piezocatalysis and water splitting. Interestingly, irradiated by ultrasound, the surface of ultasmall P-BTO nanoparticles produced imbalance charges, which induced a cascade of redox reaction processes to simultaneously generate ROS and O 2 , the latter one was hardly generated in large-sized barium titanate nanoparticles. The assynthesized P-BTO reached the highest accumulation in the tumor site at 4 h after intravenous injection. The results showed that the produced O 2 significantly alleviated the hypoxia of TME to down-regulate the expression of HIF-1α, and the produced ROS can efficiently kill tumor cells. Moreover, the tumor metastasis was also inhibited, providing a different way to treat triple-negative breast cancer, which was easily metastatic and lacked effective treatments in the clinic.

This review focus on the recent developments in inorganic nanomaterials for tumor SDT.

Tumor immunotherapy based on immune checkpoint blockade (ICB) still suffers from low host response rate and non‐specific distribution of immune checkpoint inhibitors, greatly compromising the therapeutic efficiency. Herein, cellular membrane stably expressing matrix metallopeptidase 2 (MMP2)‐activated PD‐L1 blockades is engineered to coat ultrasmall barium titanate (BTO) nanoparticle for overcoming the immunosuppressive microenvironment of tumors. The resulting M@BTO NPs can significantly promote the BTO's tumor accumulation, while the masking domains on membrane PD‐L1 antibodies are cleaved when exposure to MMP2 highly expressed in tumor. With ultrasound (US) irradiation, M@BTO NPs can simultaneously generate reactive oxygen species (ROS) and O2 based on BTO mediated piezocatalysis and water splitting, significantly promoting the intratumoral infiltration of cytotoxic T lymphocytes (CTLs) and improving the PD‐L1 blockade therapy to the tumor, resulting in effective tumor growth inhibition and lung metastasis suppression in a melanoma mouse model. This nanoplatform combines MMP2‐activated genetic editing cell membrane with US responsive BTO for both immune stimulation and specific PD‐L1 inhibition, providing a safe and robust strategy in enhancing immune response against tumor.

Enhanced PDT and siRNA transfection effect of siRNA@CpMBs were successfully achieved by in situ conversion of MBs to NPs.

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Thermosensitive liposomes have demonstrated great potential for tumor-specific chemotherapy. Near infrared (NIR) dyes loaded liposomes have also shown improved photothermal effect in cancer theranostics. However, the instability of liposomes often causes premature release of drugs or dyes, impeding their antitumor efficacy. Herein, we fabricated a highly stable thermo-responsive bubble-generating liposomal nanohybrid cerasome with a silicate framework, combined with a NIR dye to achieve NIR light stimulated, tumor-specific, chemo-photothermal synergistic therapy.Methods: In this system, NIR dye of 1,1'-Dioctadecyl-3,3,3',3'- Tetramethylindotricarbocyanine iodide (DiR) with long carbon chains was self-assembled with a cerasome-forming lipid (CFL) to encapsulate ammonium bicarbonate (ABC), which was further used for actively loading doxorubicin (DOX), affording a thermosensitive and photosensitive DOX-DiR@cerasome (ABC).Results: The resulting cerasome could disperse well in different media. Upon NIR light mediated thermal effect, ABC was decomposed to generate CO2 bubbles, resulting in a permeable channel in the cerasome bilayer that significantly enhanced DOX release. After intravenous injection into tumor-bearing mice, DOX-DiR@cerasome (ABC) could be efficiently accumulated at the tumor tissue, as monitored by DiR fluorescence, lasting for more than 5 days. NIR light irradiation was then performed at 36h to locally heat the tumors, resulting in immediate CO2 bubble generation, which could be clearly detected by ultrasound imaging, facilitating the monitoring process of controlled release of the drug. Significant antitumor efficacy could be obtained for the DOX-DiR@cerasome (ABC) + laser group, which was further confirmed by tumor tissue histological analysis.

This paper presents the design and study of a digital capacitance measuring circuit with theoretical analysis, numerical simulation, and experimental evaluation. The static and dynamic performances of the capacitance measuring circuit are first defined, including signal-to-noise ratio (SNR), standard deviation, accuracy, linearity, sensitivity, and response time, within a given measurement range. Then numerical simulation is carried out to analyze the SNR and standard deviation of the circuit, followed by experiments to validate the overall performance of the circuit. The simulation results show that when the standard deviation of noise is 0.08 mV and the measured capacitance decreases from 6 pF to 3 fF, the SNR decreases from 90 dB to 22 dB and the standard deviation is between 0.17 fF and 0.24 fF. The experimental results show that when the measured capacitance decreases from 6 pF to 40 fF and the data sampled in a single period are used for demodulation, the SNR decreases from 88 dB to 40 dB and the standard deviation is between 0.18 fF and 0.25 fF. The maximum absolute error and relative error are 5.12 fF and 1.26%, respectively. The SNR and standard deviation can be further improved if the data sampled in more than one period are used for demodulation by the circuit.

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