ABSTRACT
Fluorescent (FL) encrypting nanostructures, such as quantum dots, carbon dots, organic dyes, lanthanide nanocrystals, DNA, and more, are effective tools for advanced applications in high-resolution hidden imaging. These applications include tracking, labeling, security printing, and anti-counterfeiting drug technology. In this work, what we believe to be a new FL encoding nanostructures has been proposed, which consists of recently discovered nanometer-scale peptide dots. When refolded into a beta-sheet peptide secondary structure, these biocompatible nanoparticles exhibit a strong and tunable FL effect. The biophotonic FL covers the entire visible spectrum, making the peptide dots next-generation nanoscale light sources with a quantum yield of 30%. Our studies demonstrate that these FL bio-nanodots also exhibit a significant irreversible photo-bleaching effect associated with the light-induced destruction of noncovalent intermolecular hydrogen bonds of the peptide dots' highly stable beta-sheet secondary structure. We present what we believe is a new approach for achieving high-resolution long-term optical memory by tailoring various hidden images in the developed thin polyvinyl alcohol (PVA) polymer films with an embedded dense array of FL peptide nanodots. The technology enables recording photo-bleached patterns, barcodes, and high-resolution images.
Subject(s)
Nanoparticles , Quantum Dots , Polymers , Nanoparticles/chemistry , Quantum Dots/chemistry , Peptides , Coloring Agents , Fluorescent Dyes/chemistryABSTRACT
The evanescent light photon extraction efficiency of insulator, semiconductor and conductor amorphous nanolayers deposited on glass waveguides was evaluated from Differential Evanescent Light Intensity measurements. The Differential Evanescent Light Intensity technique uses the evanescent field scattered by the deposited nanolayer, enabling nanometer thickness profiling due to the high inherent dark background contrast. The results show that the effective evanescent photon penetration depth increases from metal to semiconductor and then to insulating layers, establishing thus the effective photon-material interaction length for the various materials classes.
