ABSTRACT
RNA interference is a fundamental gene regulatory mechanism that is mediated by the RNA-induced silencing complex (RISC). Here we report that an artificial nanoparticle complex can effectively mimic the function of the cellular RISC machinery for inducing target RNA cleavage. Our results show that a specifically designed nanozyme for the treatment of hepatitis C virus (HCV) can actively cleave HCV RNA in a sequence specific manner. This nanozyme is less susceptible to degradation by proteinase activity, can be effectively taken up by cultured human hepatoma cells, is nontoxic to the cultured cells and a xenotransplantation mouse model under the conditions studied, and does not trigger detectable cellular interferon response, but shows potent antiviral activity against HCV in cultured cells and in the mouse model. We have observed a more than 99% decrease in HCV RNA levels in mice treated with the nanozyme. These results show that this nanozyme approach has the potential to become a useful tool for functional genomics, as well as for combating protein-expression-related diseases such as viral infections and cancers.
Subject(s)
Hepacivirus/metabolism , Hepatitis C/therapy , Nanoparticles , RNA Interference , RNA, Viral/metabolism , RNA-Induced Silencing Complex/metabolism , Animals , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/therapy , Cell Line, Tumor , Hepacivirus/genetics , Hepatitis C/genetics , Hepatitis C/metabolism , Humans , Mice , Mice, Inbred NOD , Mice, SCID , Neoplasm Transplantation , RNA, Viral/genetics , RNA-Induced Silencing Complex/genetics , Transplantation, HeterologousABSTRACT
A competitive binding nonseparation electrochemical enzyme immunoassay (NEEIA) is described for the determination of microcystin-LR (MCLR) using a double-sided microporous gold electrode in cartridge-type cells. A gold film sputtered on one side of porous nylon membrane constitutes a working electrode, while another gold film formed on the opposite side serves as a pseudo reference electrode. After immobilizing MCLR antibody on working electrode by physical adsorption, the double-sided electrode was placed simply in a diffusion U-type or within a dry strip-type cell with a conjugate pad pre-loaded with a glucose oxidase labeled MCLR (GOx-MCLR) on working electrode side. Assays were performed in two steps: an MCLR-containing sample mixed with a known amount of GOx-MCLR conjugate either in buffer solution or in pre-loaded dry pad was incubated for an appropriate period (about 10 min) to induce competitive reaction with an immobilized anti-MCLR antibody on working electrode, and a fixed concentration of glucose solution (substrate) was then added to the backside of the working electrode. Due to the competitive nature of the assay, enzymatically generated product, hydrogen peroxide (H2O2), was detected at the working gold electrode (at +800 mV versus Au) by oxidation, and the magnitude of amperometric current was inversely proportional to the concentration of MCLR in the sample. The response time after substrate addition was about 30s. Mean recovery of MCLR added to tap water was 93.5%, with a coefficient of variation (CV) of 6.6%. The proposed competitive NEEIA system is in general comparable to existing heterogeneous enzyme immunoassays with a similar detection limit (100 pg/mL MCLR), and suitable for developing a disposable type biosensor for on-site monitoring of environment.
