International Journal of Molecular Sciences

Journal Browser

► Journal Browser

Special Issue Information

Dear Colleagues,

Reactive oxygen species (ROS) such as peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen are under a chemically reactive state. Even though ROS are a byproduct from the metabolism of oxygen in cells, they play a critical role in cellular signaling processes and homeostasis. The biological roles of ROS in particular are a double-edged sword. When ROS exist in cells within the appropriate level, they frequently contribute to the proliferation, migration, and homeostasis of cells. However, excessive levels of ROS normally induce cell cycle arrest, apoptosis, necrosis, or genetic alterations in biological systems and then affect the structure of cells.

From this point of view, many types of scientists, such as molecular biologists, have been investigating the molecular process of ROS production and their action in normal cells or cancer cells, while other scientists have been developing novel medicines and nanomaterials that produce ROS or are modified by ROS. For example, ROS-producing agents and/or ROS-sensitive nanomaterials in chemotherapeutic approaches are to produce excessive ROS in cells and kill cancer cells. ROS generation in cells is increasingly finding itself in the spotlight in various fields of science.

Some of the topics around reactive oxygen species to be tackled in this Special Issue include but are not limited to:

Molecular mechanism of ROS generation and its action in cells;
ROS-producing agents;
ROS-sensitive nanomaterials;
ROS-mediated drug delivery system;
ROS-mediated diagnosis of disease;
Photodynamic therapy.

Prof. Dr. Jeong Young-IL
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. There is an Article Processing Charge (APC) for publication in this open access journal. For details about the APC please see here. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

reactive oxygen species (ROS)
ROS-producing agents
ROS-sensitive nanomaterials
ROS-mediated drug delivery system
ROS-mediated diagnosis of disease
molecular mechanism of ROS generation and its action in cells

Published Papers (1 paper)

Research

21 pages, 5922 KiB

Open AccessArticle

Reactive Oxygen Species and Folate Receptor-Targeted Nanophotosensitizers Composed of Folic Acid-Conjugated and Poly(ethylene glycol)-Chlorin e6 Tetramer Having Diselenide Linkages for Targeted Photodynamic Treatment of Cancer Cells

by Seong-Won Yang, Young-IL Jeong, Min-Suk Kook and Byung-Hoon Kim

Int. J. Mol. Sci. 2022, 23(6), 3117; https://doi.org/10.3390/ijms23063117 - 14 Mar 2022

Cited by 4 | Viewed by 1933

Abstract

Folic acid-conjugated nanophotosensitizers composed of folic acid (FA), poly(ethylene glycol) (PEG) and chlorin e6 (Ce6) tetramer were synthesized using diselenide linkages for reactive oxygen species (ROS)- and folate receptor-specific delivery of photosensitizers. Ce6 was conjugated with 3-[3-(2-carboxyethoxy)-2,2-bis(2-carboxyethoxymethyl)propoxy]propanoic acid (tetra acid, or TA) to make Ce6 tetramer via selenocystamine linkages (TA-sese-Ce6 conjugates). In the carboxylic acid end group of the TA-sese-Ce6 conjugates, FA-PEG was attached again using selenocystamine linkages to make FA-PEG/TA-sese-Ce6 conjugates (abbreviated as FAPEGtaCe6 conjugates). Nanophotosensitizers were fabricated by a dialysis procedure. In the morphological observations, they showed spherical shapes with small diameters of less than 200 nm. Stability of the aqueous FAPEGtaCe6 nanophotosensitizer solution was maintained (i.e., their particle sizes were not significantly changed until 7 days later). When H₂O₂ was added to the nanophotosensitizer solution, the particle size distribution was changed from a monomodal pattern to a multimodal pattern. In addition, the fluorescence intensity and Ce6 release rate from the nanophotosensitizers were also increased by the addition of H₂O₂. These results indicated that the nanophotosensitizers had ROS-sensitive properties. In an in vitro cell culture study, an FAPEGtaCe6 nanophotosensitizer treatment against cancer cells increased the Ce6 uptake ratio, ROS generation and light-irradiated cytotoxicity (phototoxicity) compared with Ce6 alone against various cancer cells. When the folic acid was pretreated to block the folate receptors of the Y79 cells and KB cells (folate receptor-overexpressing cells), the intracellular Ce6 uptake, ROS generation and thereby phototoxicity were decreased, while the MCF-7 cells did not significantly respond to blocking of the folate receptors. These results indicated that they could be delivered by a folate receptor-mediated pathway. Furthermore, an in vivo pulmonary metastasis model using Y79 cells showed folate receptor-specific delivery of FAPEGtaCe6 nanophotosensitizers. When folic acid was pre-administered, the fluorescence intensity of the lungs was significantly decreased, indicating that the FAPEGtaCe6 nanophotosensitizers had folate receptor specificity in vitro and in vivo. We suggest that FAPEGtaCe6 nanophotosensitizers are promising candidates for a targeted photodynamic therapy (PDT) approach against cancer cells. Full article

(This article belongs to the Special Issue Reactive Oxygen Species—Related Materials and Medicine, Volume II)

► Show Figures