PH and redox triggered doxorubicin release from covalently linked carbon dots conjugates

Sajini D. Hettiarachchi, Emel Kirbas Cilingir, Heidi Maklouf, Elif S. Seven, Suraj Paudyal, Steven Vanni, Regina M. Graham, Roger M. Leblanc

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Tumor microenvironment responsive drug delivery systems are potential approaches to reduce the acute toxicity caused by high-dose cancer chemotherapy. Notwithstanding the conventional nano-drug delivery systems, the redox and pH stimuli drug delivery systems are currently gaining attention. Therefore, the current study was designed to compare three different covalent carbon dots (C-dots) systems based on doxorubicin (dox) release profiles and cancer cell viability efficacy under acidic and physiological conditions. The C-dots nanosystems that were examined in this study are directly conjugated (C-dots-dox), pH triggered (C-dots-HBA-dox), and the redox stimuli (C-dots-S-S-dox) conjugates. The drug loading content (DLC%) of the C-dots-S-S-dox, C-dots-HBA-dox, and C-dots-dox was 34.2 ± 0.4, 60.0 ± 0.3, and 70.0 ± 0.2%, respectively, that examined by UV-vis spectral analysis. The dox release paradigms were emphasized that all three conjugates were promisingly released the dox from C-dots faster in acidic pH than in physiological pH. The displayed highest dox released percentage in the acidic medium was 74.6 ± 0.8% obtained by the pH stimuli, C-dots-HBA-dox conjugate. When introducing the redox inducer, dithiothreitol (DTT), preferentially, the redox stimuli C-dot-S-S-dox conjugate demonstrated a faster dox release at acidic pH than in the pH 7.4. The SJGBM2 cell viability experiments revealed that the pH stimuli, C-dots-HBA-dox conjugate, displayed a significant cell viability drop in the artificially acidified pH 6.4 medium. However, in the physiological pH, the redox stimuli, C-dots-S-S-dox conjugate, was promising over the pH stimuli C-dots-HBA-dox, exhibiting cell viability of 60%, though its' efficacy dropped slightly in the artificially acidified pH 6.4 medium. Moreover, the current study illustrates the stimuli conjugates' remarkable efficacy on sustain drug release than direct amide linkage. This journal is

Original languageEnglish (US)
Pages (from-to)5507-5518
Number of pages12
Issue number10
StatePublished - Mar 14 2021

ASJC Scopus subject areas

  • Materials Science(all)


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