NanoScript: A Nanoparticle-Based Artificial Transcription Factor for Effective Gene Regulation

Transcription factor (TF) proteins are master regulators of transcriptional activity and gene expression. TF-based gene regulation is a promising approach for many biological applications; however, several limitations hinder the full potential of TFs. Herein, we developed an artificial, nanoparticle-based transcription factor, termed NanoScript, which is designed to mimic the structure and function of TFs. NanoScript was constructed by tethering functional peptides and small molecules called synthetic transcription factors, which mimic the individual TF domains, onto gold nanoparticles. We demonstrate that NanoScript localizes within the nucleus and initiates transcription of a reporter plasmid by over 15-fold. Moreover, NanoScript can effectively transcribe targeted genes on endogenous DNA in a nonviral manner. Because NanoScript is a functional replica of TF proteins and a tunable gene-regulating platform, it has great potential for various stem cell applications

Impact of Morphological Inhomogeneity on Excitonic States in Highly Mismatched Alloy ZnSe_1–<i>X</i>Te_<i>X</i> Nanocrystals

ZnSe1–XTeX nanocrystals (NCs) are promising photon emitters with tunable emission across the violet to orange range and near-unity quantum yields. However, these NCs suffer from broad emission line widths and multiple exciton decay dynamics, which discourage their practicable use. Here, we explore the excitonic states in ZnSe1–XTeX NCs and their photophysical characteristics in relation to the morphological inhomogeneity of highly mismatched alloys. Ensemble and single-dot spectroscopic analysis of a series of ZnSe1–XTeX NC samples with varying Te ratios coupled with computational calculations shows that, due to the distinct electronegativity between Se and Te, nearest-neighbor Te pairs in ZnSe1–XTeX alloys create localized hole states spectrally distributed approximately 130 meV above the 1Sh level of homogeneous ZnSe1–XTeX NCs. This forms spatially separated excitons (delocalized electron and localized hole in trap), accounting for both inhomogeneous and homogeneous line width broadening with delayed recombination dynamics. Our results identify photophysical characteristics of excitonic states in NCs made of highly mismatched alloys and provide future research directions with potential implications for photonic applications