Covalent Conjugation of Carbon Dots with Plasmid and DNA Condensation Thereafter: Realistic Insights into the Condensate Morphology, Energetics, and Photophysics

Nanomaterials for Fluorescence and Multimodal Bioimaging

Bioconjugated nanomaterials replace molecular probes in bioanalysis and bioimaging in vitro and in vivo. Nanoparticles of silica, metals, semiconductors, polymers, and supramolecular systems, conjugated with contrast agents and drugs for image-guided (MRI, fluorescence, PET, Raman, SPECT, photodynamic, photothermal, and photoacoustic) therapy infiltrate into preclinical and clinical settings. Small bioactive molecules like peptides, proteins, or DNA conjugated to the surfaces of drugs or probes help us to interface them with cells and tissues. Nevertheless, the toxicity and pharmacokinetics of nanodrugs, nanoprobes, and their components become the clinical barriers, underscoring the significance of developing biocompatible next-generation drugs and contrast agents. This account provides state-of-the-art advancements in the preparation and biological applications of bioconjugated nanomaterials and their molecular, cell, and in vivo applications. It focuses on the preparation, bioimaging, and bioanalytical applications of monomodal and multimodal nanoprobes composed of quantum dots, quantum clusters, iron oxide nanoparticles, and a few rare earth metal ion complexes.

Biomass derived self-assembled DNA-dot hydrogels for enhanced bacterial annihilation

Nanotization of biomass for interesting biomedical applications is still in the nascent stage with no visible market available products. While products derived from biomass DNA and protein have unquestionable biocompatibility, induction of desired properties needs careful manipulation of the biomolecules. Herein, for the first time, we report the transformation of onion derived biomass DNA into DNA-dots through its partial hydrothermal pyrolysis to induce improved mechanical and photophysical properties. The DNA-dots were further used as crosslinkers to create a hydrogel through hybridization-mediated self-assembly with untransformed genomic DNA. The DNA dot-DNA hydrogel sustainably delivers the ciprofloxacin antibiotic as well as produces on-demand reactive oxygen species (ROS) with visible light irradiation. This prompted us to explore the hydrogel as a topical formulation for combination antibiotic Antibacterial-Photodynamic Therapy (APDT) applications. Remarkable annihilation of E. coli and S. aureus, and most importantly two drug-resistant strains of E. coli, shows the success of our sustainable approach.