Highlights
Abstract
The aim of this study is to synthesize the cobalt iron oxide (CoFe) and doxorubicin (Dox)-loaded chitosan bilirubin (ChiBil) nanoparticles and to investigate the anticancer therapeutic effect of the synthesized nanoparticles under magnetic guidance in a colon cancer.
ChiBil-CoFe-Dox nanoparticles were synthesized by conjugating CoFe and Dox and then loaded onto ChiBil nanoparticles. Synthesis were characterized using thermogravimetric (TGA) analysis, inductive coupled plasma (ICP) analysis, dynamic light scattering (DLS), zeta potential and field emission-transmission electron microscopy (FE-TEM). Cellular uptake and cytotoxicity studies were conducted in vitro. Biodistribution and tumor inhibition study was done in vivo CT-26 colon cancer model.
The ChiBil-CoFe-Dox nanoparticles were successfully synthesized in this study. The in vitro cytotoxicity study showed that the ChiBil-CoFe-Dox nanoparticle had a toxic effect on cancer cells. The accumulation of ChiBil-CoFe-Dox nanoparticles was enhanced under magnetic guidance, as observed by in vivo. Tumor inhibition study showed that the ChiBil-CoFe-Dox nanoparticle effectively reduced tumor size in vivo mice colon cancer model, especially when combined with magnetic guidance.
This study showed that ChiBil-CoFe-Dox nanoparticle was successfully synthesized and effectively reduced tumor size, especially when combined with magnetic guidance. The in vitro and in vivo results suggested that the ROS stimuli responsive ChiBil-CoFe-Dox nanoparticles may be a potent therapeutic option for treating colon cancer.
Graphical Abstract
Introduction
Anticancer therapy primarily relies on surgical intervention to remove tumors and the use of chemotherapeutic agents to kill tumor cells. While surgical techniques aim to minimize invasiveness and facilitate a rapid return to daily life, chemotherapy encompasses the development of chemotherapeutic agents and drug delivery methods [1]. The limitations associated with chemotherapy, such as its significant side effects and relatively low efficacy, have posed enduring challenges. These challenges have created a pressing need to explore and develop innovative technologies that can offer more efficient and safer alternatives for anticancer therapies [2], [3].
Emerging nanotechnologies, using various functional nanomaterials, have demonstrated their effectiveness and potential as promising strategies in the field of anticancer treatment. [4], [5], [6]. The conjugation of chitosan and bilirubin (ChiBil) has been explored for drug delivery applications due to their biocompatibility and ability to enhance drug stability and release [7].
Bilirubin, often associated with jaundice, also serves as an antioxidant in the body. It scavenges harmful free radicals, like reactive oxygen species (ROS), produced during normal cellular processes. By neutralizing ROS, bilirubin helps prevent oxidative damage to cells and tissues. Its antioxidant activity extends to inhibiting lipid peroxidation, protecting cell membranes from degradation [8]. ROS, induce oxidative modifications to bilirubin molecules, leading to the formation of biliverdin. This conversion involves the oxidation of bilirubin's double bonds, resulting in the production of biliverdin, a hydrophilic molecule. Further action of ROS can degrade bilirubin to bilirubin oxidation products (BOXes) that is eliminated from the body [9]. ROS responsive bilirubin oxidation and nanoparticle destabilization leading to drug release have been explored recently [10], [11]. ChiBil NP with ROS-responsive drug release properties minimize drug release in healthy tissues, but maximize drug release in cancer cells under oxidative stress conditions [11]. Combining DOX-loaded nanoparticles with anticancer drugs with different modes of action can overcome anticancer drug resistance and synergize therapeutic effects [12], [13].
Magnetic nanoparticles (MNP) have gained increasing attention as a promising drug delivery system due to their unique properties, such as high surface area, biocompatibility, and magnetic responsiveness [14], [15], [16]. The enhanced permeability and retention (EPR) effect allows nanoparticles to accumulate selectively in tumor tissues, plays a crucial role in tumor targeting and drug delivery [17], [18]. To further enhance the magnetic properties of MNPs, cobalt ions can be incorporated into the MNP, resulting in CoFe nanoparticles. CoFe nanoparticles possess diverse biomedical applications including targeted drug delivery, MR imaging, and magnetic hyperthermia treatment [19], [20], [21], [22]. Nanoparticles composed of CoFe are being actively engineered to enhance their magnetic properties while simultaneously optimizing their safety profile to minimize toxicity. CoFe nanoparticles have been shown to exhibit stronger magnetic properties than iron oxide nanoparticle [14]. The increased drug release rate at lower pH validates their effectiveness as therapeutic agents in the mildly acidic environment of tumors [19].
The hypothesis of this study is that enhanced magnetic property of CoFe nanoparticles will increase the targeting effect to cancer cells by magnetic guidance. Currently, there are no reports on stimuli-responsive CoFe nanoparticle delivery for treating cancer. The aim of this study is to synthesize ChiBil-CoFe-DOX nanoparticle and to investigate the anticancer therapeutic effect of the synthesized nanoparticles under magnetic guidance in a colon cancer model.
Section snippets
Materials
Glycol Chitosan was procured from Sigma Aldrich (Merck KGaA, Darmstadt, Germany), while Chlorin e6 was acquired from Santa Cruz Biotechnology (Dallas, Texas, United States). Bilirubin (TCI, Chuo-ku, Tokyo), EDC (1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide) (Sigma Aldrich (Merck), New Jersey,USA), and NHS (N-Hydroxysuccinimide) (Sigma Aldrich (Merck), New Jersey,USA were also obtained for the study. CT-26 cells, provided by Professor In-Kyu Park's laboratory at Chonnam National University
Synthesis of ChiBil-CoFe-DOX
FE-TEM analysis showed formation of 10 nm CoFe nanoparticle and Bio-TEM analysis shows 200–300 nm size ChiBil-CoFe-DOX nanoparticle with CoFe and DOX loading. DLS measurement showed hydrodynamic size of 300–400 nm validating TEM size measurement of ChiBil-CoFe-DOX. The nanoparticle is able to closely pack 10 nm CoFe inside hydrophobic core of bilirubin hiding it from biological environment. This close packing allows high loading efficiency of CoFe and thereby enhanced magnet sensitivity (Fig. 1
Discussion
This work is to synthesize ChiBil-CoFe-DOX nanoparticles as a promising drug delivery system for targeted cancer therapy. This study is the first to investigate the use of CoFe in a drug delivery application where it is loaded onto biocompatible polymers of chitosan and bilirubin to increase their stability and enhance their ability to target cancer cells and release drugs. MNPs made of iron oxide have gained a lot of attention in the last decade due to their elemental properties, which render
Conclusion
This study showed that ChiBil-CoFe-DOX nanoparticle was successfully synthesized and effectively reduced tumor size, especially when combined with magnetic guidance. The in vitro and in vivo results suggested that the ROS stimuli responsive ChiBil-CoFe-DOX nanoparticles may be a potent therapeutic option for treating colon cancer.
Statement of human and animal rights
The animal experiment was conducted in agreement with the National Institutes of Health Guide for the Care and Use of Laboratory Animals and approved by the Chonnam National University Medical School Research Institutional Animal Care and Use Committee (CNU IACUC-H-2019–6).
CRediT authorship contribution statement
Reju Thomas: Writing – review & editing, Writing – original draft, Visualization, Methodology, Formal analysis. Subin Kim: Writing – original draft, Visualization, Resources, Methodology, Formal analysis. Hyo Kang: Writing – review & editing, Writing – original draft, Methodology, Investigation, Data curation, Conceptualization. Jae Kyun Ju: Supervision. Yong Yeon Jeong: Writing – review & editing, Validation, Supervision, Resources, Project administration, Investigation, Funding acquisition,
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
References (35)
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