Full Color Modulation of Firefly Luciferase through Engineering with Unified Stark Effect

The firefly luciferase has been a unique marking tool used in various bioimaging techniques. Extensive color modulation is strongly required to meet special marking demands; however, intentional and accurate wavelength tuning has yet to be achieved. Here, we demonstrate that the color shift of the firefly chromophore (OxyLH₂-1) by internal and external fields can be described as a unified Stark shift. Electrostatic microenvironmental effects on fluorescent spectroscopy are modeled in vacuo through effective electric fields by using time-dependent density functional theory. A complete visible fluorescence spectrum of firefly chromophore is depicted, which enables one to control the emission in a specific color. As an application, the widely observed pH-correlated color shift is proved to be associated with the local Stark field generated by the trace water–ions (vicinal hydronium and hydroxide ions) at active sites close to the OxyLH₂-1

Bioheterojunction Effect on Fluorescence Origin and Efficiency Improvement of Firefly Chromophores

We propose the heterojunction effect in the analysis of the fluorescence mechanism of the firefly chromophore. Following this analysis, and with respect to the HOMO−LUMO gap alignment between the chromophore’s functional fragments, three main heterojunction types (I, II, and I*) are identified. Time-dependent density functional theory optical absorption calculations for the firefly chromophore show that the strongest excitation appears in the deprotonated anion state of the keto form. This can be explained by its high HOMO−LUMO overlap due to strong bioheterojunction confinement. It is also found that the nitrogen atom in the thiazolyl rings, due to its larger electronegativity, plays a key role in the emission process, its importance growing when the HOMO and LUMO overlap at its location. This principle is applied to enhance the chromophore’s fluorescence efficiency and to guide the functionalization of molecular optoelectronic devices

One-Pot Synthesis of Superfine Core–Shell Cu@metal Nanowires for Highly Tenacious Transparent LED Dimmer

We demonstrate a one-pot, low-cost, and scalable method for fast synthesis of superfine and uniform core–shell Cu nanowires (NWs) coated with optional metals and/or alloy. Cu NWs in high aspect ratio (>3000) were synthesized through an oleylamine-mediated solution method, and tunable shell coating was performed by injecting metal-organic precursors at the last stage of reaction. Superfine Cu@metal NWs (Ti, Zn, V, Ni, Ag, NiZn, etc) were achieved in diameter of ∼30 nm and length of ∼50 μm. Transparent conductive films were obtained by imprinting method, showing high optoelectronic performance (51 Ω/sq at 93% transmittance), high mechanical tenacity over bending, twisting, stretching, and compressing, and robust antioxidant ability (high temperature and high humidity). A transparent film dimmer for light-emitting diode (LED) lighting was fabricated with the stretchable Cu@Ti NWs network. The LED luminance could be accurately tuned by the deformation strain of Cu@Ti NWs film

One-Pot Synthesis of Superfine Core–Shell Cu@metal Nanowires for Highly Tenacious Transparent LED Dimmer

We demonstrate a one-pot, low-cost, and scalable method for fast synthesis of superfine and uniform core–shell Cu nanowires (NWs) coated with optional metals and/or alloy. Cu NWs in high aspect ratio (>3000) were synthesized through an oleylamine-mediated solution method, and tunable shell coating was performed by injecting metal-organic precursors at the last stage of reaction. Superfine Cu@metal NWs (Ti, Zn, V, Ni, Ag, NiZn, etc) were achieved in diameter of ∼30 nm and length of ∼50 μm. Transparent conductive films were obtained by imprinting method, showing high optoelectronic performance (51 Ω/sq at 93% transmittance), high mechanical tenacity over bending, twisting, stretching, and compressing, and robust antioxidant ability (high temperature and high humidity). A transparent film dimmer for light-emitting diode (LED) lighting was fabricated with the stretchable Cu@Ti NWs network. The LED luminance could be accurately tuned by the deformation strain of Cu@Ti NWs film