Microwave-Assisted Synthesis of Carbon Dot - Iron Oxide Nanoparticles for Fluorescence Imaging and Therapy.

Seokhwan Chung,Miqin Zhang

doi:10.3389/fbioe.2021.711534

Seokhwan Chung, Miqin Zhang

Open Access

https://doi.org/10.3389/fbioe.2021.711534

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Abstract

Fluorescence microscopy is commonly used to image specific parts of a biological system, and is applicable for early diagnosis of cancer. Current fluorescent probes, such as organic dyes and quantum dots, suffer from poor solubility and high toxicity, respectively, demonstrating a need for a colloidal stable and non-toxic fluorescent probe. Here we present an iron oxide and carbon dot (CD) based nanoparticle (CNPCP) that displays optical properties similar to those of conventional fluorescent probe and also exhibits good biocompatibility. Fluorescent CDs were synthesized from glucosamine onto chitosan – polyethylene glycol (PEG) graft copolymer using microwave irradiation. These NPs were monodispersed in aqueous environments and displayed excitation-dependent fluorescence; they demonstrated good size stability and fluorescence intensity in biological media. In vitro evaluation of CNP as fluorescent probes in cancer cell lines showed that these NPs caused little toxicity, and allowed fast and quantitative imaging. Model therapeutic doxorubicin (DOX) was conjugated onto the NPs (CNPCP-DOX) to demonstrate the multifunctionality of the NPs, and in vitro studies showed that CNPCP-DOX was able to kill cancer cells in a dose dependent manner. These results indicate the potential of using CNPCPs as fluorescent probes capable of delivering chemotherapeutics.

Highlights

Fluorescence microscopy is a powerful tool used for selective imaging of tissues, cells, and organelles
Iron oxide nanoparticles coated with chitosan-polyethylene glycol (PEG) copolymer and carbon dots (CNPCP) were synthesized using a coprecipitation method
The chitosan-PEG coating provided the initial solubility in aqueous environments, and the steric stability imparted by the PEG kept the coated iron oxide nanoparticles with CD incorporated (CNPCP) well-dispersed without aggregation

Summary

INTRODUCTION

Fluorescence microscopy is a powerful tool used for selective imaging of tissues, cells, and organelles. CDs can be synthesized through other methods such as electrolysis and hydro/solvothermal treatment These reactions do not allow precise control over physical and optical properties, and require strong oxidizing reagents as part of the synthesis process. Compared to these methods, the microwave irradiation yields more uniform products, and is a safer and faster approach to synthesis of CDs. Though the chemical reaction is complex and not yet fully understood, many reports suggest that glucose-based CDs are an ideal alternative to fluorophores (Agbenyega, 2012). The therapeutic effect of the resultant NP-DOX conjugate was evaluated through assessment of cell viability after incubation with various doses

MATERIALS AND METHODS

Evaluation of Cellular Uptake of CNPCP

RESULTS

DISCUSSION

DATA AVAILABILITY STATEMENT