Copper Nanosheet-Based Wash-Free Fluorescence Imaging of Cancer Cells.

Near-infrared fluorescence (NIRF) probes greatly facilitate in vivo imaging of various biologically important species. However, there are several significant limitations such as consuming washing steps, photobleaching, and low signal intensity. Herein, we synthesized fluorescent copper nanosheets templated with DNA scaffolds (DNS/CuNSs). We employ them and Cy5.5 of the fluorescence resonance energy transfer (FRET) system, which have a larger Stokes shift (∼12-fold) than the traditional NIRF dye Cy5.5. Based on their excellent fluorescence properties, we employ DNS/CuNSs-Cy5.5 for fluorescence probes in cancer cell imaging. Compared with the free Cy5.5 fluorescence probe, the novel fluorescence imaging probe implements wash-free imaging and exhibits enhanced anti-photobleaching ability (∼5.5-fold). Moreover, the FRET system constructed by DNS/CuNSs has a higher signal amplification ability (∼4.17-fold), which is more similar to that of Cu nanoclusters prepared with DNA nanomonomers as a template. This work provides a new idea for cancer cell MCF-7 imaging and is expected to promote the development of cancer cell fluorescence imaging.

Self-assembly of Copper Nanoclusters Using DNA Nanoribbon Templates for Sensitive Electrochemical Detection of H2O2 in Live Cells.

The excessive secretion of H2O2 within cells is closely associated with cellular dysfunction. Therefore, high sensitivity in situ detection of H2O2 released from living cells was valuable in clinical diagnosis. In the present work, a novel electrochemical cells sensing platform by synthesizing copper nanoclusters (CuNCs) at room temperature based on DNA nanoribbon (DNR) as a template (DNR-CuNCs). The tight and ordered arrangement of nanostructured assemblies of DNR-CuNCs conferred the sensor with superior stability (45 days) and electrochemical performance. The MUC1 aptamer extending from the DNR template enabled the direct capture MCF-7 cells on electrode surface, this facilitated real-time monitoring of H2O2 release from stimulated MCF-7 cells. While the captured MCF-7 cells on the electrode surface significantly amplified the current signal of H2O2 release compared with the traditional electrochemical detection H2O2 released signal by MCF-7 cells in PBS solution. The approach provides an effective strategy for the design of versatile sensors and achieving monitored cell release of H2O2 in long time horizon (10 h). Thereby expanding the possibilities for detecting biomolecules from live cells in clinical diagnosis and biomedical applications.

Tannic acid-based nanopesticides coating with highly improved foliage adhesion to enhance foliar retention.

Poor utilization efficiency of conventional pesticide formulation has resulted in overuse, which could increase costs, toxicity to other non-target organisms, concerns about human health and safety, groundwater contamination, causing ecosystem destruction and food pollution. The folia-adhesive formulation is supposed to enhance foliar retention time and utilization efficiency. According to the microstructure of the foliage, the nanopesticides surfaces were modified by affinity groups to improve folia adhesion and decrease the loss from crop foliage. In this study, tannic acid, a bioadhesive natural molecule, has been applied to develop abamectin nanopesticide (Abam-PLA-Tannin-NS) and azoxystrobin nanopesticide (Azox-PLA-Tannin-NS) with strong adhesion to foliage by chemical modification. Abam-PLA-Tannin-NS and Azox-PLA-Tannin-NS presented better photostability and continuous release behavior. The retention rates of Abam-PLA-Tannin-NS and Azox-PLA-Tannin-NS on the foliage was remarkably enhanced by more than 50%, compared with unmodified nanopesticides. Resultantly, the indoor toxicity of Abam-PLA-Tannin-NS and antifungal activity of Azox-PLA-Tannin-NS were enhanced. The interaction force between tannic acid coating nanoparticles and foliage was mainly from hydrogen bonding. Our findings could be beneficial to develop novel leaf-adhesive nanopesticides with high retention time and bioavailability.