PUBLICATION

A ratiometric theranostic nanoplatform with acid-triggered drug release and glutathione-activated fluorescence turn-on

Authors
Flores-Cruz, R.D., Figueroa-DePaz, Y., Lobita, M.C., Hernández-Ayala, L.F., López-Pacheco, A.P., Dijkstra, E., Ruiz-Azuara, L., Santos, H.A.
ID
ZDB-PUB-251012-10
Date
2025
Source
Journal of controlled release : official journal of the Controlled Release Society : 114309114309 (Journal)
Registered Authors
Keywords
Cancer, Glutathione depletion, Ratiometric response, Theragnostics, Tumor detection
MeSH Terms
  • Animals
  • Antineoplastic Agents*/administration & dosage
  • Antineoplastic Agents*/chemistry
  • Cell Line, Tumor
  • Coordination Complexes*/administration & dosage
  • Coordination Complexes*/chemistry
  • Copper/administration & dosage
  • Copper/chemistry
  • Drug Delivery Systems
  • Drug Liberation
  • Female
  • Fluorescence
  • Fluorescent Dyes/administration & dosage
  • Fluorescent Dyes/chemistry
  • Folic Acid/chemistry
  • Glutathione*/chemistry
  • Glutathione*/metabolism
  • Humans
  • Quantum Dots/administration & dosage
  • Quantum Dots/chemistry
  • Theranostic Nanomedicine/methods
  • Zebrafish
  • Zinc Oxide/administration & dosage
  • Zinc Oxide/chemistry
PubMed
41076139 Full text @ J. Control Release
Abstract
Theragnostic nanomedicines that precisely coordinate drug delivery with imaging remain a significant challenge. Here, we report a novel nanoformulation that integrates acid-sensitive drug release with a glutathione (GSH)-activated fluorescence turn-on mechanism for targeted cancer therapy and real-time tracking. Our system is based on folic acid-functionalized zinc oxide quantum dots (QFZnO) loaded with a third-generation Casiopeina drug, IIIGCas, a copper-based coordination compound. Upon reaching the acidic tumor microenvironment, IIIGCas is released, subsequent intracellular GSH reduction converts the non-fluorescent Cu(II) complex into a highly fluorescent Cu(I) adduct, activating a distinct "turn-ON" signal. Computational studies reveal that this redox switch suppresses photoinduced electron transfer, restoring the emission of the drug's intrinsic curcumin-derived fluorophore and amplifying its fluorescence by sixfold. This mechanism creates a dual-emission system, enabling the simultaneous ratiometric tracking of nanocarrier (QFZnO) localization and drug activation. The nanoplatform demonstrated enhanced potency, showing statistically significant cytotoxicity in cervical and triple-negative breast cancer cell lines at far lower doses than free IIIGCas. In vivo, using zebrafish xenograft models, it achieved precise tumor targeting and a 90 % reduction in primary tumor area, while effectively illuminating secondary micrometastases. This work provides a generalizable blueprint for designing intelligent metal-complex delivery systems that optically report their own therapeutic activation in real-time.
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