Photodynamic Therapy for Inflammatory and Cancerous Diseases of the Intestines: Molecular Mechanisms and Prospects for Application

Sep 24, 2026

Photodynamic therapy (PDT) is a minimally invasive modality that targets both cancer and inflammatory disorders with recognized efficacy, low toxicity, and potential for repeated administration. Colorectal cancer (CRC) and inflammatory bowel diseases (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), impose a major burden on intestinal health worldwide. Preclinical work supports PDT for IBD and CRC, while clinical studies are in progress. The review summarizes molecular mechanisms underlying PDT’s anti-inflammatory and anti-tumor effects and discusses prospects for clinical application, aiming to inform future CRC and IBD research.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages18

Reading Time45 min

AccessFree to download

Introduction

Core PDT components and photochemical pathways

ROS generation and Type I/Type II reactions

Dose-based PDT categories (high-dose vs low-dose)

Inflammatory bowel disease and CRC context

IBD as a contributor to colorectal cancer

Ivyspring International Publisher InternationalJournal of Biological Sciences 2023; 19(15): 4793-4810. doi: 10.7150/ijbs.87492 Review Photodynamic Therapy for Inflammatory and Cancerous Diseases of the Intestines: Molecular Mechanisms and Prospects for Application Beiying Deng1\#, Kunpeng Wang2\#, Lilong Zhang2, Zhendong Qiu2, Weiguo Dong1􀀍, Weixing Wang2􀀍 1. Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, China. 2. Department of General Surgery, Renmin Hospital of Wuhan University, Wuhan, China. \# These authors have contributed equally to this work. 􀀍 Corresponding author: Weiguo Dong AND Weixing Wang. [dongweiguo@whu.edu.cn](dongweiguo@whu.edu.cn) and [wangwx@whu.edu.cn](wangwx@whu.edu.cn). © The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License ([https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/)). See [http://ivyspring.com/terms](http://ivyspring.com/terms) for full terms and conditions. Received: 2023.06.26; Accepted: 2023.08.21; Published: 2023.09.04 Abstract Photodynamic therapy (PDT) is a minimally invasive treatment that effectively targets cancer and inflammatory diseases. It has gained recognition for its efficacy, low toxicity, and potential for repeated use. Colorectal cancer (CRC) and inflammatory bowel diseases (IBD), including Crohn's disease (CD), and ulcerative colitis (UC), impose a significant burden on global intestinal health, with increasing incidence and prevalence rates. PDT shows promise as an emerging approach for gastrointestinal disease treatment, particularly IBD and CRC. Extensive preclinical research has demonstrated the safety and effectiveness of PDT for IBD and CRC, while clinical studies are currently underway. This review provides an overview of the underlying mechanisms responsible for the anti-inflammatory and anti-tumor effects of PDT, offering insights into the clinical application of PDT in IBD and CRC treatment. It is expected that this review will serve as a valuable reference for future research on PDT for CRC and IBD, contributing to advancements in the treatment of inflammatory and cancerous diseases of the intestines. Keywords: photodynamic therapy; inflammatory bowel diseases; colorectal cancer; reactive oxygen species; immunology; nanomedicine 1. Introduction Photodynamic therapy (PDT) is a highly effective and minimally invasive treatment for cancer and inflammatory diseases, known for its recognized efficacy, low toxicity, and suitability for repeated administration [1] . The procedure involves the application of a photosensitizer (PS) to the targeted area, followed by exposure to specific light [2] . The PS selectively targets rapidly proliferating cells, making it a versatile and effective treatment option for various medical conditions [3, 4] . PDT comprises three essential components: excitation light, PS, and oxygen. Table S1 summarized the types of PS and its application in various medical conditions. The choice of PS type and its application in different conditions depends on factors like disease type and stage, tumor location, specific PS properties, and treatment objectives. When a PS is exposed to light of a specific wavelength, it undergoes two types of photochemical reactions that lead to the generation of reactive oxygen species (ROS) [5] . In Type I reactions, the PS transfers energy to biomolecules while in the T1 excited state, causing a transfer of hydrogen or electrons between the photosensitizerand substrate. Subsequently, interacting with oxygen molecules produces superoxide anion radicals, which generate ROS within the cells. Conversely, in Type II reactions, the PS is excited to the triplet state, and its energy directly transfers to ground-state oxygen molecules, resulting in the production of highly oxidizing singlet oxygen [1] . PDT can be categorized into High-dose (HDPDT) and lo

FAQs

What are the main components of photodynamic therapy (PDT)?

PDT requires excitation light, a photosensitizer (PS), and oxygen. After PS is applied to the target area, light exposure triggers photochemical reactions that generate reactive oxygen species.

How do Type I and Type II photochemical reactions differ?

In Type I reactions, the excited PS transfers hydrogen or electrons to biomolecules and oxygen ultimately contributes to reactive oxygen species formation. In Type II reactions, energy transfer occurs directly to ground-state oxygen, producing singlet oxygen.

What are the key differences between high-dose PDT (HDPDT) and low-dose PDT (LDPDT)?

HDPDT generates ROS more efficiently, which can damage cellular structures and support anti-vascular tumor effects, but may harm adjacent healthy intestinal tissue due to PS accumulation. LDPDT is associated with preventing mucosal damage and strong immunomodulatory effects, including regulation of intestinal bacterial strains and promotion of neovascular closure.

Sep 24, 2026

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