We present a sensing platform based on the morphological changes of plasmonic nanoparticles. Detection is achieved by using a stimulus-responsive polyelectrolyte-aptamer thin film to control the rate of diffusion of etchants that alter the shape and size of the nanoparticles. We show that the extent of morphological change and the colorimetric response depends on the amount of analyte bound. Contrary to conventional plasmonic sensors, our detection scheme does not rely on any interparticle interaction and is completely label-free, both in terms of the analyte and the capture probe. It presents new opportunities for designing facile, low-cost, and portable chip-based sensors for biodiagnostic and field analysis.

Current guidance by leading public health agencies recommends wearing a 3-layer cloth-based face mask with a middle non-woven material insert to reduce the transmission of infectious respiratory viruses like SARS-CoV-2....

Portable, easy-to-use and cost-effective sensing devices are desirable in healthcare, environmental monitoring and food safety. Herein we employ polyelectrolyte-aptamer (PE-aptamer) multilayered films that exhibit target-responsive permeability for colorimetric and electrochemical sensing. We present the quantitative detection of an exemplary small molecule, quinine, and address the potential for detection in complex media by examining interference effects. We optimize the film composition and investigate the importance of the structural-switching ability of the aptamer. The results from both platforms are corroborated to provide an outlook on the applicability of the PE-aptamer film for sensing. The label-free detection combined with the readily adaptive assembly process could be invaluable for diverse analytical fields.

We employ imaging mass cytometry (IMC) to investigate in vitro uptake and cellular distribution of DNA-functionalized gold nanoparticles (AuNPs). IMC enables the multiparametric imaging of cell components and allows for the detection of AuNPs in cells with >100 times higher sensitivity than conventional confocal fluorescence imaging, as each nanoparticle contains thousands of atoms for signal amplification. Changes in the accumulation of nanoparticles in cells due to oligonucleotide sequence-dependent interactions are exploited to examine a model biomarker for hypoxia–microRNA-210. We find that AuNPs functionalized with microRNA-210-targeting sequence accumulate in hypoxic cells 3 to 4-fold compared to normoxic cells. The work examines the potential use of DNA-AuNP as high-mass probes for the analysis of nonabundant nucleic acids.

The sensitivity of the formation of plasmonic silver nanoprisms to hydrogen peroxide is explored for the colorimetric detection of catalase activity in bacteria.

We investigated the reduction of organic compounds photocatalyzed by Mn2+-doped CdS/ZnS quantum dot (Mn:CdS/ZnS QD) films. The incorporation of Mn2+ ion into the CdS nanocrystals as a dopant promotes Auger...

<div>Current guidance by leading public health agencies recommends wearing a 3-layer cloth-based face mask with a middle non-woven material insert to reduce the transmission of infectious respiratory viruses like SARS-CoV-2. In this work we explore the material characteristics for a range of readily available non-woven materials and their sub-micron particle filtration efficiency (PFE), with the aim of providing evidence-based guidelines for selecting appropriate materials as inserts in cloth-based masks. We observed a wide range of ideal PFE for the tested non-woven materials, with polypropylene, Swiffer and Rayon/polyester blend providing the highest PFE and breathability. Our results suggest that materials comprising loose 3D fibrous webs (e.g. flannel, Swiffer and gauze) exhibited enhanced filtration efficiency compared to compressed counterparts. Common modifications to fabrics, such as water-resistant treatment and a sewn seam were also investigated. Overall, we demonstrate that adding an appropriate non-woven material as an insert filter can significantly improve the performance of cloth-based masks, and there exist suitable cellulose-based alternatives to polypropylene.</div>

<div>Current guidance by leading public health agencies recommends wearing a 3-layer cloth-based face mask with a middle non-woven material insert to reduce the transmission of infectious respiratory viruses like SARS-CoV-2. In this work we explore the material characteristics for a range of readily available non-woven materials and their sub-micron particle filtration efficiency (PFE), with the aim of providing evidence-based guidelines for selecting appropriate materials as inserts in cloth-based masks. We observed a wide range of ideal PFE for the tested non-woven materials, with polypropylene, Swiffer and Rayon/polyester blend providing the highest PFE and breathability. Our results suggest that materials comprising loose 3D fibrous webs (e.g. flannel, Swiffer and gauze) exhibited enhanced filtration efficiency compared to compressed counterparts. Common modifications to fabrics, such as water-resistant treatment and a sewn seam were also investigated. Overall, we demonstrate that adding an appropriate non-woven material as an insert filter can significantly improve the performance of cloth-based masks, and there exist suitable cellulose-based alternatives to polypropylene.</div>