Intrinsic Peroxidase-Mimicking Ir Nanoplates for Nanozymatic Anticancer and Antibacterial Treatment

© 2020 American Chemical Society. The study of inorganic nanozymes to overcome the disadvantages of bio-enzymes, such as the requirement of optimized reaction conditions and lack of durability against environmental factors, is one of the most significant research topics at present. In this work, we comprehensively analyzed the intrinsic peroxidase-like activity of Ir-based nanoparticles, the biological and nanozymatic potentials of which have not yet been explored. These particles were synthesized by the galvanic replacement of Ag nanoplates with Ir. Through the confirmed peroxidase-like activity and hydrogen peroxide decomposition with free radical generation facilitated by these particles, the antibacterial and anticancer effects were successfully verified in vitro. The nanozyme-based therapeutic effect observed at concentrations at which these nanoparticles do not show cytotoxicity suggests that it is possible to achieve more precise and selective local treatment with these particles. The observed highly efficient peroxidase-like activity of these nanoparticles is attributed to the partially mixed composition of Ir-Ag-IrO2 formed through the galvanic replacement reaction in the synthetic process11sciescopu

Quantitative and Multiplexed MicroRNA Sensing in Living Cells Based on Peptide Nucleic Acid and Nano Graphene Oxide (PANGO)

MicroRNA (miRNA) is an important small RNA which regulates diverse gene expression at the post-transcriptional level. miRNAs are considered as important biomarkers since abnormal expression of specific miRNAs is associated with many diseases including cancer and diabetes. Therefore, it is important to develop biosensors to quantitatively detect miRNA expression levels. Here, we develop a nanosized graphene oxide (NGO) based miRNA sensor, which allows quantitative monitoring of target miRNA expression levels in living cells. The strategy is based on tight binding of NGO with peptide nucleic acid (PNA) probes, resulting in fluorescence quenching of the dye that is conjugated to the PNA, and subsequent recovery of the fluorescence upon addition of target miRNA. PNA as a probe for miRNA sensing offers many advantages including high sequence specificity, high loading capacity on the NGO surface compared to DNA and resistance against nuclease-mediated degradation. The present miRNA sensor allowed the detection of specific target miRNAs with the detection limit as low as similar to 1 pM and the simultaneous monitoring of three different miRNAs in a living cell.N