Dewetting Process of Silver Thin Films and Its Application on Percolative Pressure Sensors with High Sensitivity.

This work reports on an innovative dewetting process of silver thin films to realize percolative nanoparticle arrays (NPAs) and demonstrates its application on highly sensitive pressure sensors. The dewetting process, which is a simple and promising technique, synthesizes NPAs by breaking the as-deposited metal film into randomly distributed islands. The NPA properties, such as the mean particle size and the spacing between adjacent particles, can be easily tailored by controlling the dewetting temperature, as well as the as-deposited metal-film thickness. The fabricated NPAs were employed to develop gauge pressure sensors with high sensitivity. The proposed sensor consists of a sealed reference-pressure cavity, a polyimide (PI) membrane patterned with an interdigital electrode pair (IEP), and a silver NPA deposited on the IEP and the PI membrane. The operational principle of the device is based on the NPA percolation effect with deformation-dependence. The fabricated sensors exhibit rapid responses and excellent linearity at around 1 atm. The maximum sensitivity is about 0.1 kPa-1. The advantages of the proposed devices include ultrahigh sensitivity, a reduced thermal disturbance, and a decreased power consumption. A practical application of this pressure sensor with high resolution was demonstrated by using it to measure the relative floor height of a building.

Chemotherapy with PLGA microspheres containing docetaxel decreases angiogenesis in human hepatoma xenograft.

To investigate the antiangiogenic effect of sustained-release poly (lactic-co-glycolic acid) microspheres containing docetaxel (PMCD) in human hepatoma xenograft. PMCD were prepared by solvent evaporation method with an encapsulation efficiency of 98.7% and a release period of about 3 weeks in vitro. PMCD were intratumorally injected once for mice bearing a human hepatocellular carcinoma. On day 21 post-treatment, the inhibition rate of tumor growth was 72.7% in the high-dose group, indicating a significant antitumor activity. Meanwhile, excellent antiangiogenic effect was observed based on the contrast-enhanced ultrasonography as well as microvessel density determination. Additionally, the real-time fluorescence quantitative PCR revealed that the expressions of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and angiopoietin-2 (Ang2) genes were down-regulated significantly. Interstitial chemotherapy using PMCD was highly effective and safe for the treatment of the human hepatoma xenograft and that decreasing angiogenesis could be one of the most important mechanisms involved in the antitumor activity.

Interstitial chemotherapy using thermosensitive gel-coated ricin in nude mice bearing a human hepatoma.

AIM: To investigate the anti-tumor effects and mechanisms of interstitial chemotherapy using intra-tumor injection of thermosensitive gel-coated ricin in nude mice bearing a human hepatoma. METHODS: In a subcutaneous mouse model of hepatoma, saline, blank gel, ricin, or thermosensitive gel-coated ricin (TGR) was injected directly into tumors. Fourteen days later, eight mice in each group were sacrificed. The tumors were removed and weighed for calculating tumor growth inhibition rate. Serum alpha-fetoprotein levels, as well as hepatic and renal functions, were measured. Tumor tissue was analyzed under an optical microscope. Terminal deoxynucleotidyl transferase mediated dUTP nick end labeling was used to detect the apoptotic index. Moreover, caspase-3 activity and protein expression in tumor tissue were examined. The survival time of the tumor bearing mice was determined. RESULTS: Following interstitial chemotherapy by intra-tumor injection of TGR in nude mice, serum alpha-fetoprotein levels were significantly reduced with no significant impact on hepatic or renal functions. The rate of tumor growth inhibition was 58.5% following a single, local injection. Histological analysis revealed abundant necrosis. The apoptotic index was 45.96 +/- 7.41%. Caspase-3 activity was increased, and caspase-3 protein was significantly activated in tumor cells. Compared to the saline group, the survival time of mice in the TGR group was significantly extended. At the observation terminal time, day 120, two mice were still alive and fully recovered. CONCLUSION: Interstitial chemotherapy by intra-tumor injection of TGR was highly efficient and safe for the treatment of nude mice bearing a human hepatoma. Interstitial chemotherapy exhibits inhibitory effects by inducing apoptosis and directly killing tumor cells.

US-guided interstitial chemotherapy using paclitaxel temperature-responsive gel for breast cancer treatment in rat.

INTRODUCTION: This study aims to investigate the therapeutic effect of paclitaxel temperature-responsive gel (PTRG) for interstitial chemotherapy on breast cancer, and to explore a new minimally invasive treatment for breast cancer. MATERIALS AND METHODS: Breast cancer models were induced in rats using subcutaneous transplantation of tumor cells. The rats were then divided into control, paclitaxel injection, gel injection and paclitaxel-gel (PG) group. Following treatment, all animals were checked regularly by ultrasonography to observe changes in the tumors. Biopsy tumor tissues were processed for histopathological examination, and apoptotic index was determined by the terminal deoxynucleotidyl transferase dUTP nick end labeling method. In addition, blood cell count and liver transaminase activity were monitored, and the survival time of rats with cancer recorded. RESULTS: Rats in PG group exhibited liquefaction necrosis of tumors. Ninety days after the experiment, four rats exhibited complete extinction of tumors, indicating full recovery. Pathological examination revealed that the tumor tissues in these rats were mostly necrotic, and the apoptotic index of tumor cells increased markedly compared to PI group. Also, the red blood cell, hemoglobin and white blood cell levels declined significantly in the PI group compared with PG group, while glutamic-pyruvic transaminase and glutamic-oxalacetic transaminase activities significantly increased. Meanwhile, no toxicity due to treatment was observed in PG group. CONCLUSION: Interstitial chemotherapy mediated by PTRG appeared to be a safe and effective treatment for breast cancer in rats. It might have clinical applications for treating human breast cancer.