Preparation of Multifunctional N-Doped Carbon Quantum Dots from Citrus clementina Peel: Investigating Targeted Pharmacological Activities and the Potential Application for Fe3+ Sensing.

Silvija Šafranko,Aleksandar Széchenyi,Anamarija Stanković,Maja Herak Bosnar,Igor Weber,Yogendra Kumar Mishra,Sandra Kraljević Pavelić,Sugato Hajra,Hoe-Joon Kim,Maja Dutour-Sikirić,Stela Jokić,Ivica Strelec,Petra Grbčić,Igor Jerković

doi:10.3390/ph14090857

Abstract

Carbon quantum dots (CQDs) have recently emerged as innovative theranostic nanomaterials, enabling fast and effective diagnosis and treatment. In this study, a facile hydrothermal approach for N-doped biomass-derived CQDs preparation from Citrus clementina peel and amino acids glycine (Gly) and arginine (Arg) has been presented. The gradual increase in the N-dopant (amino acids) nitrogen content increased the quantum yield of synthesized CQDs. The prepared CQDs exhibited good biocompatibility, stability in aqueous, and high ionic strength media, similar optical properties, while differences were observed regarding the structural and chemical diversity, and biological and antioxidant activity. The antiproliferative effect of CQD@Gly against pancreatic cancer cell lines (CFPAC-1) was observed. At the same time, CQD@Arg has demonstrated the highest quantum yield and antioxidant activity by DPPH scavenging radical method of 81.39 ± 0.39% and has been further used for the ion sensing and cellular imaging of cancer cells. The obtained results have demonstrated selective response toward Fe3+ detection, with linear response ranging from 7.0 µmol dm−3 to 50.0 µmol dm−3 with R2 = 0.9931 and limit of detection (LOD) of 4.57 ± 0.27 µmol dm−3. This research could be a good example of sustainable biomass waste utilization with potential for biomedical analysis and ion sensing applications.

Highlights

Over the last decade, there has been growing interest in developing biocompatible fluorescent nanomaterials which could represent a safe substitute to the toxic metal luminescent nanoparticles
The preparation of Carbon quantum dots (CQDs) from Citrus clementina peel is an example of the efficient utilization of biomass waste for the development of nanomaterials with potential applications in biomedical analysis and ion sensing
Carbon quantum dots derived from organic precursors undergo five main phases: thermal decomposition, condensation, polymerization, carbonization, and surface passivation [24,25]

Summary

Introduction

There has been growing interest in developing biocompatible fluorescent nanomaterials which could represent a safe substitute to the toxic metal luminescent nanoparticles. Due to their excellent optical properties, carbon dots have gained considerable attention with benefits to biomedical and biological applications. The “bottom-up“ approach has gained considerable attention for the facile and efficient fabrication of nanoparticles by the carbonization process of organic precursors through solvothermal, hydrothermal, microwave, and ultrasonication treatments [3]. Among the “bottom-up“ approaches, hydrothermal synthesis is the most commonly used method for obtaining CQDs due to its simplicity and outstanding efficiency in obtaining water-soluble materials with high quantum yield (QY) [4]

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Conclusion