Amphiphilic Fullerene-BODIPY Photosensitizers for Targeted Photodynamic Therapy

Graphene-Based Photodynamic Therapy and Overcoming Cancer Resistance Mechanisms: A Comprehensive Review

Photodynamic therapy (PDT) is a non-invasive therapy that has made significant progress in treating different diseases, including cancer, by utilizing new nanotechnology products such as graphene and its derivatives. Graphene-based materials have large surface area and photothermal effects thereby making them suitable candidates for PDT or photo-active drug carriers. The remarkable photophysical properties of graphene derivates facilitate the efficient generation of reactive oxygen species (ROS) upon light irradiation, which destroys cancer cells. Surface functionalization of graphene and its materials can also enhance their biocompatibility and anticancer activity. The paper delves into the distinct roles played by graphene-based materials in PDT such as photosensitizers (PS) and drug carriers while at the same time considers how these materials could be used to circumvent cancer resistance. This will provide readers with an extensive discussion of various pathways contributing to PDT inefficiency. Consequently, this comprehensive review underscores the vital roles that graphene and its derivatives may play in emerging PDT strategies for cancer treatment and other medical purposes. With a better comprehension of the current state of research and the existing challenges, the integration of graphene-based materials in PDT holds great promise for developing targeted, effective, and personalized cancer treatments.

Recent developments in photodynamic therapy and its application against multidrug resistant cancers

Recently, photodynamic therapy (PDT) has received a lot of attention for its potential use in cancer treatment. It enables the therapy of a multifocal disease with the least amount of tissue damage. The most widely used prodrug is 5-aminolevulinic acid, which undergoes heme pathway conversion to protoporphyrin IX, which acts as a photosensitizer (PS). Additionally, hematoporphyrin, bacteriochlorin, and phthalocyanine are also studied for their therapeutic potential in cancer. Unfortunately, not every patient who receives PDT experiences a full recovery. Resistance to different anticancer treatments is commonly observed. A few of the resistance mechanisms by which cancer cells escape therapeutics are genetic factors, drug-drug interactions, impaired DNA repair pathways, mutations related to inhibition of apoptosis, epigenetic pathways, etc. Recently, much research has been conducted to develop a new generation of PS based on nanomaterials that could be used to overcome cancer cells' multidrug resistance (MDR). Various metal-based, polymeric, lipidic nanoparticles (NPs), dendrimers, etc, have been utilized in the PDT application against cancer. This article discusses the detailed mechanism by which cancer cells evolve towards MDR as well as recent advances in PDT-based NPs for use against multidrug-resistant cancers.

Zero-Dimensional Carbon Nanomaterials for Fluorescent Sensing and Imaging

Advances in nanotechnology and nanomaterials have attracted considerable interest and play key roles in scientific innovations in diverse fields. In particular, increased attention has been focused on carbon-based nanomaterials exhibiting diverse extended structures and unique properties. Among these materials, zero-dimensional structures, including fullerenes, carbon nano-onions, carbon nanodiamonds, and carbon dots, possess excellent bioaffinities and superior fluorescence properties that make these structures suitable for application to environmental and biological sensing, imaging, and therapeutics. This review provides a systematic overview of the classification and structural properties, design principles and preparation methods, and optical properties and sensing applications of zero-dimensional carbon nanomaterials. Recent interesting breakthroughs in the sensitive and selective sensing and imaging of heavy metal pollutants, hazardous substances, and bioactive molecules as well as applications in information encryption, super-resolution and photoacoustic imaging, and phototherapy and nanomedicine delivery are the main focus of this review. Finally, future challenges and prospects of these materials are highlighted and envisaged. This review presents a comprehensive basis and directions for designing, developing, and applying fascinating fluorescent sensors fabricated based on zero-dimensional carbon nanomaterials for specific requirements in numerous research fields.

Enhanced Photodynamic Therapy by Improved Light Energy Capture Efficiency of Porphyrin Photosensitizers

OPINION STATEMENT

Photodynamic therapy (PDT) has garnered increasing attention in cancer treatment because of its advantages such as minimal invasiveness and selective destruction. With the development of PDT, impressive progress has been made in the preparation of photosensitizers, particularly porphyrin photosensitizers. However, the limited tissue penetration of the activating light wavelengths and relatively low light energy capture efficiency of porphyrin photosensitizers are two major disadvantages in conventional photosensitizers. Therefore, tissue penetration needs to be enhanced and the light energy capture efficiency of porphyrin photosensitizers improved through structural modifications. The indirect excitation of porphyrin photosensitizers using fluorescent donors (fluorescence resonance energy transfer) has been successfully used to address these issues. In this review, the enhancement of the light energy capture efficiency of porphyrins is discussed.

Cooperative Functionalities in Porous Nanoparticles for Seeking Extracellular DNA and Targeting Pathogenic Biofilms via Photodynamic Therapy

Many pathogenic bacteria are getting more and more resistant against antibiotic treatment and even become up to 1.000× times more resilient in the form of a mature biofilm. Thus, one is currently prospecting for alternative methods for treating microbial infections, and photodynamic therapy is a highly promising approach by creating so-called reactive oxygen species (ROS) produced by a photosensitizer (PS) upon irradiation with light. Unfortunately, the unspecific activity of ROS is also problematic as they are harmful to healthy tissue as well. Notably, one knows that uncontrolled existence of ROS in the body plays a major role in the development of cancer. These arguments create need for advanced theranostic materials which are capable of autonomous targeting and detecting the existence of a biofilm, followed by specific activation to combat the infection. The focus of this contribution is on mesoporous organosilica colloids functionalized by orthogonal and localized click-chemistry methods. The external zone of the particles is modified by a dye of the Hoechst family. The particles readily enter a mature biofilm where adduct formation with extracellular DNA and a resulting change in the fluorescence signal occurs, but they cannot cross cellular membranes such as in healthy tissue. A different dye suitable for photochemical ROS generation, Acridine Orange, is covalently linked to the surfaces of the internal mesopores. The spectral overlap between the emission of Hoechst with the absorption band of Acridine Orange facilitates energy transfer by Förster resonance with up to 88% efficiency. The theranostic properties of the materials including viability studies were investigated in vitro on mature biofilms formed by Pseudomonas fluorescens and prove the high efficacy.

NI-BODIPY-GO Nanocomposites for Targeted PDT

Three multifunctional targeted NI-BODIPYs (10-12) and GO-(10-12) nanocarriers were fabricated. NI-BODIPYs are designed to facilitate non-covalent interaction with graphene oxide (GO) and target toward cancer cells for specific recognition with glucose moieties while efficiently producing singlet oxygen. We probed detailed characterization, fundamental photophysical/photochemical properties, and interactions with GO of such triplet photosensitizers and nanocarriers. The effect of the formation of nanohybrids with GO on singlet oxygen formation as well as on the efficacies of the molecules in terms of in vitro killing of cancer cells was evaluated with K562 human chronic myelogenous leukemia cells. Amazingly, it was observed that GO exhibited favorable interactions with the NI-BODIPY dyads and promoted the formation of singlet oxygen, while not showing any dark toxicity.

Development of novel polymeric nanoagents and their potential in cancer diagnosis and therapy runing title: Polymeric nanoagents for cancer theranostics

Cancer has been one of the leading factors of death around the world. Cancer patients usually have low 5-year survival rates and poor life quality requiring substantial improvement. In clinic, the presenting diagnostic strategies lack sensitivity with only a small proportion of patients can be accurately identified. For diagnosed patients, most of them are at the advanced stages thus being delayed to receive treatment. Therefore, it is eager to investigate and develop highly effective and accurate techniques for cancer early diagnosis and individualized therapy. Various nanoplatforms are emerging as imaging agents and drug carriers for cancer theranostics recently. Novel polymeric nanoagents, as a potent exemplar, have extraordinary merits, such as good stability, high biosafety and high drug loading efficacy, showing the great prospect for cancer early diagnosis and precise treatment. Herein, we review the recent advances in novel polymeric nanoagents and elucidate their synthesis procedures. We further introduce the applications of novel polymeric nanoagents in cancer diagnosis, treatment, and theranostics, as well as associated challenges and prospects in this field.

Combined Photodynamic and Photothermal Therapy and Immunotherapy for Cancer Treatment: A Review

Photoactivation therapy based on photodynamic therapy (PDT) and photothermal therapy (PTT) has been identified as a tumour ablation modality for numerous cancer indications, with photosensitisers and photothermal conversion agents playing important roles in the phototherapy process, especially in recent decades. In addition, the iteration of nanotechnology has strongly promoted the development of phototherapy in tumour treatment. PDT can increase the sensitivity of tumour cells to PTT by interfering with the tumour microenvironment, whereas the heat generated by PTT can increase blood flow, improve oxygen supply and enhance the PDT therapeutic effect. In addition, tumour cell debris generated by phototherapy can serve as tumour-associated antigens, evoking antitumor immune responses. In this review, the research progress of phototherapy, and its research effects in combination with immunotherapy on the treatment of tumours are mainly outlined, and issues that may need continued attention in the future are raised.

Effect of Chitosan and Amphiphilic Polymers on the Photosensitizing and Spectral Properties of Rose Bengal

The influence of chitosan (CS) and amphiphilic polymers (AP: pluronic F108 and polyvinylpyrrolidone (PVP)) on the photocatalytic activity of rose bengal (RB) in a model reaction of tryptophan photo-oxidation in phosphate-buffered saline (PBS) was studied. It was shown that in the presence of CS, the effective rate constant k_eff of tryptophan photo-oxidation catalyzed by RB in PBS solution decreases by a factor of two. This is due to the ionic interaction of the RB with the chitosan. Rose bengal in a slightly acidic environment (pH 4.5) passes into a neutral lactone form, which sharply reduces the photosensitizing properties of the dye. It was demonstrated that the introduction of AP into a solution containing RB and CS prevents direct interaction between RB and CS. This is evidenced by the presence of photocatalytic activity of the dye in the RB-AP-CS systems, as well as bathochromic shifts of the main absorption bands of the dye, and an increase in the optical density and luminescence intensity of the RB when AP is introduced into a buffer solution containing RB and chitosan. The presence of RB-CS and RB-AP interaction in aqueous and PBS media is confirmed by the increase in the degree of fluorescence anisotropy (r) of these binary systems. In an aqueous solution, the value of r for the RB-F108-CS system decreases by a factor of 3.5 (compared to the value of r for the RB-CS system), which is associated with the localization of the dye in pluronic micelles. In PBS, the fluorescence anisotropy is practically the same for all systems, which is related to the stability of the dye structure in this medium. The presence of interaction between RB and AP in aqueous solutions was confirmed by the proton NMR method. In addition, the formation of RB-F108 macromolecular complexes, which form associates during solution concentration (in particular, during evaporation), was shown by AFM. Such RB-AP-CS systems may be promising for practical application in the treatment of local foci of infections by aPDT.

Self-Assembly Catalase Nanocomplex Conveyed by Bacterial Vesicles for Oxygenated Photodynamic Therapy and Tumor Immunotherapy

Background

Photodynamic therapy (PDT) is an effective therapeutic modality that has been extensively studied in treatment of various cancers. However, issues with inadequate oxygen (O₂) concentration in tumor tissue and inadequate immune response generation have hindered its successful application in tumor therapy.

Methods

Firstly, the self-assembly nanocomplex (CAT-Ce6), which is composed of hydrophilic catalase and hydrophobic photosensitizer Chlorin e6 (Ce6), was fabricated to support oxygenated PDT. Secondly, for supplying PDT with enhanced antitumoral immunity, CAT-Ce6 was coated with PD-L1 antibody modified-attenuated Salmonella outer membrane vesicles (OMV-aPDL1). Finally, the catalytic activity, tumor targeting, hypoxia ameliorating, immune effect initiating and anti-tumor capacities of the integral nanosystem CAT-Ce6@OMV-aPDL1 were evaluated systematically.

Results

The self-assembly nanocomplex (CAT-Ce6) generated sufficient O₂ and promoted the solubility of Ce6 simultaneously, which enhanced PDT significantly. OMV-aPDL1 inherited most of the immunogenic membrane-associated components from the parent bacteria, possessing immunomodulation ability for immunosuppressive tumor microenvironment reprogramming and reducing immune escape. The obtained nanosystem CAT-Ce6@OMV-aPDL1 durably relieved hypoxia, resulting in amplifying PDT-mediated cytotoxicity to generate a pool of tumor-associated antigens, stimulating anti-tumor immune responses and even inducing an immune memory effect, which inhibited tumor development efficiently.

Conclusion

The resultant CAT-Ce6@OMV-aPDL1 displays excellent efficacy of PDT and immunotherapy to achieve antitumor effects, which provides a new avenue for combinatorial therapy against various cancers.