Synthesis of a photostable near-infrared-absorbing photosensitizer for selective photodamage to cancer cells

Recent Strategies to Develop Innovative Photosensitizers for Enhanced Photodynamic Therapy

This review presents a robust strategy to design photosensitizers (PSs) for various species. Photodynamic therapy (PDT) is a photochemical-based treatment approach that involves the use of light combined with a light-activated chemical, referred to as a PS. Attractively, PDT is one of the alternatives to conventional cancer treatment due to its noninvasive nature, high cure rates, and low side effects. PSs play an important factor in photoinduced reactive oxygen species (ROS) generation. Although the concept of photosensitizer-based photodynamic therapy has been widely adopted for clinical trials and bioimaging, until now, to our surprise, there has been no relevant review article on rational designs of organic PSs for PDT. Furthermore, most of published review articles in PDT focused on nanomaterials and nanotechnology based on traditional PSs. Therefore, this review aimed at reporting recent strategies to develop innovative organic photosensitizers for enhanced photodynamic therapy, with each example described in detail instead of providing only a general overview, as is typically done in previous reviews of PDT, to provide intuitive, vivid, and specific insights to the readers.

Photoacoustic Imaging Quantifies Drug Release from Nanocarriers via Redox Chemistry of Dye-Labeled Cargo

We report a new approach to monitor drug release from nanocarriers via a paclitaxel-methylene blue conjugate (PTX-MB) with redox activity. This construct is in a photoacoustically silent reduced state inside poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PTX-MB@PLGA NPs). During release, PTX-MB is spontaneously oxidized to produce a concentration-dependent photoacoustic signal. An in vitro drug-release study showed an initial burst release (25 %) between 0-24 h and a sustained release between 24-120 h with a cumulative release of 40.6 % and a 670-fold increase in photoacoustic signal. An in vivo murine drug release showed a photoacoustic signal enhancement of up to 649 % after 10 hours. PTX-MB@PLGA NPs showed an IC50 of 78 μg mL-1 and 44.7±4.8 % decrease of tumor burden in an orthotopic model of colon cancer via luciferase-positive CT26 cells.

Mesoporous silica nanoparticles incorporating squaraine-based photosensitizers: a combined experimental and computational approach

A combined experimental–computational approach allowed a correlation of the homogeneity of the dispersion of squaraine dyes within mesoporous silica nanoparticles with their photosensitizer activity.

Synthesis and Evaluation of a Tetra[6,7]quinoxalinoporphyrazine-based Near Infrared Photosensitizer

Here we report a near infrared, water-soluble, functional and dendrimeric photosensitizer (PS) based on quinoxalinoporphyrazine structure. The photophysical properties and in vitro photodynamic therapy results suggest that this quinoxalinoporphyrazine-based dendrimer may serve as an efficient near infrared (NIR) PS platform.

Ru(II)-Catalyzed Regiospecific C-H/O-H Oxidative Annulation to Access Isochromeno[8,1-ab]phenazines: Far-Red Fluorescence and Live Cancer Cell Imaging

A facile ruthenium(II)-catalyzed regiospecific C-H/O-H oxidative annulation methodology was developed to construct isochromeno[8,1-ab]phenazines. This methodology delivers various advantages, such as scope for diverse substrates, tolerance to a range of functional groups, stability under air, and yields regioselective products. This methodology was successfully applied to synthesize far red (FR) fluorescent probes for live cancer cell imaging. The synthesized compounds displayed notable fluorescence properties in solution and thin-film. Their application in live cancer cell imaging was investigated using various cancer cell lines. The synthesized compound showed prominent FR fluorescence, with high quantum yield, and exhibited better cell-imaging properties, with excellent biocompatibility.

A Dual Anticancer Efficacy Molecule: A Selective Dark Cytotoxicity Photosensitizer

Unlike traditional binary nanostructures that construct chemotherapy drugs and photodynamic therapy photosensitizers, we introduce a molecule with a chemo-photodynamic dual therapy function. A water-soluble aggregation-induced emission enhancement (AIEE) fluorogen, NV-12P, was designed and synthesized based on asymmetric 1,6-disubstituted naphthalene and can generate particular reactive oxygen species to undergo type I photodynamic therapy under irradiation. Furthermore, this compound can specifically localize in mitochondria and, after biological evaluation, can cause mitochondrial dysfunction and potent cytotoxicity to cancer cells but not normal cells. We conclude that this compound is a potential dual-toxic efficacy molecule because it exhibits selective dark cytotoxicity and efficient photodamage in cancer cells. Additionally, we also supported the optimal combinational treatment course for the best chemo-phototherapy efficacy.

Phenothiazine and pyridine-N-oxide-based AIE-active triazoles: synthesis, morphology and photophysical properties

AIE triazoles based on phenothiazine and pyridine-N-oxide units provided micro- and nano-crystals with an emission enhancement of 233-fold higher.