Phototheranostics for NIR fluorescence image guided PDT/PTT with extended conjugation and enhanced TICT

All organic nanomedicine for PDT-PTT combination therapy of cancer cells in hypoxia

Photodynamic and photothermal therapies are promising treatments for cancer, dermatological, and ophthalmological conditions. However, photodynamic therapy (PDT) is less effective in oxygen-deficient tumor environments. Combining PDT with photothermal therapy (PTT) can enhance oxygen supply and treatment efficacy. Inorganic PTT agents pose toxicity risks, limiting their clinical use despite their high performance. In this study, we developed a novel nanomedicine integrating an all-organic photothermal agent and an organic photosensitizer, creating a colocalized nanoplatform to enhance phototherapy efficacy in cancer treatment. PTT nanoparticles (NPs) were synthesized through a thermal phase transition of organic chromophores, demonstrating superior photothermal properties and photostability. Utilizing this nanoplatform, we devised 'Combi NPs' for combined PDT-PTT nanomedicine. Tests on A549 cancer cell lines have revealed that Combi NPs exhibit superior cytotoxicity and induce apoptosis in hypoxic conditions, outperforming PTT-only NPs. The all-organic Combi NPs show significant potential for clinical cancer phototherapy in hypoxic microenvironments, potentially mitigating long-term nanomedicine accumulation and associated toxicity.

Novel BODIPY-based nano-biomaterials with enhanced D-A-D structure for NIR-triggered photodynamic and photothermal therapy

Near-infrared (NIR) responsive nanoparticles are an important platform for multimodal phototherapy. Importantly, the simultaneous NIR-triggered photodynamic (PDT) and photothermal (PTT) therapy is a powerful approach to increase the antitumor efficiency of phototherapic nanoparticles due to the synergistic effect. Herein, a boron dipyrromethene (BODIPY)-based amphiphilic dye with enhanced electron donor-acceptor-donor (D-A-D) structure (BDP-AP) was designed and synthesized, which could self-assemble into stable nanoparticles (BDP-AP NPs) for the synergistic NIR-triggered PDT/PTT therapy. BDP-AP NPs synchronously generated singlet oxygen (1O2) and achieved preeminent photothermal conversion efficiency (61.42%). The in vitro and in vivo experiments showed that BDP-AP NPs possessed negligible dark cytotoxicity and infusive anticancer performance. BDP-AP NPs provide valuable guidance for the construction of PDT/PTT-synergistic NIR nanoagents to improve the efficiency of photoinduced cancer therapy in the future.

Recent advances in functional nucleic acid decorated nanomaterials for cancer imaging and therapy

Nanomaterials possess unusual physicochemical properties including unique optical, magnetic, electronic properties, and large surface-to-volume ratio. However, nanomaterials face some challenges when they were applied in the field of biomedicine. For example, some nanomaterials suffer from the limitations such as poor selectivity and biocompatibility, low stability, and solubility. To address the above-mentioned obstacles, functional nucleic acid has been widely served as a powerful and versatile ligand for modifying nanomaterials because of their unique characteristics, such as ease of modification, excellent biocompatibility, high stability, predictable intermolecular interaction and recognition ability. The functionally integrating functional nucleic acid with nanomaterials has produced various kinds of nanocomposites and recent advances in applications of functional nucleic acid decorated nanomaterials for cancer imaging and therapy were summarized in this review. Further, we offer an insight into the future challenges and perspectives of functional nucleic acid decorated nanomaterials.

A comprehensive review on singlet oxygen generation in nanomaterials and conjugated polymers for photodynamic therapy in the treatment of cancer

A key role in lessening humanity's continuous fight against cancer could be played by photodynamic therapy (PDT), a minimally invasive treatment employed in the medical care of a range of benign disorders and malignancies. Cancerous tissue can be effectively removed by using a light source-excited photosensitizer. Singlet oxygen and reactive oxygen species are produced via the photosensitizer as a result of this excitation. In the recent past, researchers have put in tremendous efforts towards developing photosensitizer molecules for photodynamic treatment (PDT) to treat cancer. Conjugated polymers, characterized by their efficient fluorescence, exceptional photostability, and strong light absorption, are currently under scrutiny for their potential applications in cancer detection and treatment through photodynamic and photothermal therapy. Researchers are exploring the versatility of these polymers, utilizing sophisticated chemical synthesis and adaptable polymer structures to create new variants with enhanced capabilities for generating singlet oxygen in photodynamic treatment (PDT). The incorporation of photosensitizers into conjugated polymer nanoparticles has proved to be beneficial, as it improves singlet oxygen formation through effective energy transfer. The evolution of nanotechnology has emerged as an alternative avenue for enhancing the performance of current photosensitizers and overcoming significant challenges in cancer PDT. Various materials, including biocompatible metals, polymers, carbon, silicon, and semiconductor-based nanomaterials, have undergone thorough investigation as potential photosensitizers for cancer PDT. This paper outlines the recent advances in singlet oxygen generation by investigators using an array of materials, including graphene quantum dots (GQDs), gold nanoparticles (Au NPs), silver nanoparticles (Ag NPs), titanium dioxide (TiO2), ytterbium (Yb) and thulium (Tm) co-doped upconversion nanoparticle cores (Yb/Tm-co-doped UCNP cores), bismuth oxychloride nanoplates and nanosheets (BiOCl nanoplates and nanosheets), and others. It also stresses the synthesis and application of systems such as amphiphilic block copolymer functionalized with folic acid (FA), polyethylene glycol (PEG), poly(β-benzyl-L-aspartate) (PBLA10) (FA-PEG-PBLA10) functionalized with folic acid, tetra(4-hydroxyphenyl)porphyrin (THPP-(PNIPAM-b-PMAGA)4), pyrazoline-fused axial silicon phthalocyanine (HY-SiPc), phthalocyanines (HY-ZnPcp, HY-ZnPcnp, and HY-SiPc), silver nanoparticles coated with polyaniline (Ag@PANI), doxorubicin (DOX) and infrared (IR)-responsive poly(2-ethyl-2-oxazoline) (PEtOx) (DOX/PEtOx-IR NPs), particularly in NIR imaging-guided photodynamic therapy (fluorescent and photoacoustic). The study puts forward a comprehensive summary and a convincing justification for the usage of the above-mentioned materials in cancer PDT.

Side-chain engineering of organic photothermal agents for boosting further red-shifted absorption and higher photothermal therapeutic effect

Although organic photothermal agents (PTAs) have been extensively studied in preclinical cancer photothermal therapy (PTT), the internal mechanism, particularly the impact of side chains on photothermal performance, remains inadequately investigated. Herein, we conducted a systematic comparison of the photothermal properties between two organic molecules, namely O-IDTBR with four n-octyl chains and EH-IDTBR with four 2-ethylhexyl chains. With the same conjugated main structure, both O-IDTBR and EH-IDTBR exhibited nearly identical absorption properties (with a peak at 629 nm) in their molecular states. Interestingly, after the formation of nanoparticles (NPs), O-IDTBR NPs with linear alkyl chains exhibit a further red-shifted absorption onset (peak at 711 nm) compared to EH-IDTBR NPs (peak at 662 nm) with branched alkyl chains. Additionally, the photothermal conversion efficiency of O-IDTBR NPs was calculated of 33.7%, which is higher than that of EH-IDTBR NPs (27.7%). This can be attributed to the fact that linear alkyl chains of O-IDTBR NPs promote more intramolecular motions at the aggregated state by extending intermolecular distance and distorting molecular conformation. Therefore, the nonradiative thermal deactivation-induced photothermal property can be further enhanced. Through both in vitro and in vivo experiments, O-IDTBR NPs exhibit effective PTT effect and excellent biocompatibility. This study not only introduces a novel PTA but also opens new avenues for exploring organic optical nano-agents through side-chain engineering to adjust intramolecular motions at the aggregated state.

Recent Advances of Diketopyrrolopyrrole Derivatives in Cancer Therapy and Imaging Applications

Cancer is threatening the survival of human beings all over the world. Phototherapy (including photothermal therapy (PTT) and photodynamic therapy (PDT)) and bioimaging are important tools for imaging-mediated cancer theranostics. Diketopyrrolopyrrole (DPP) dyes have received more attention due to their high thermal and photochemical stability, efficient reactive oxygen species (ROS) generation and thermal effects, easy functionalization, and tunable photophysical properties. In this review, we outline the latest achievements of DPP derivatives in cancer therapy and imaging over the past three years. DPP-based conjugated polymers and small molecules for detection, bioimaging, PTT, photoacoustic imaging (PAI)-guided PTT, and PDT/PTT combination therapy are summarized. Their design principles and chemical structures are highlighted. The outlook, challenges, and future opportunities for the development of DPP derivatives are also presented, which will give a future perspective for cancer treatment.

Orthogonal Optimization, Characterization, and In Vitro Anticancer Activity Evaluation of a Hydrogen Peroxide-Responsive and Oxygen-Reserving Nanoemulsion for Hypoxic Tumor Photodynamic Therapy

Tumor hypoxia can seriously impede the effectiveness of photodynamic therapy (PDT). To address this issue, two approaches, termed in situ oxygen generation and oxygen delivery, were developed. The in situ oxygen generation method uses catalysts such as catalase to decompose excess H₂O₂ produced by tumors. It offers specificity for tumors, but its effectiveness is limited by the low H₂O₂ concentration often present in tumors. The oxygen delivery strategy relies on the high oxygen solubility of perfluorocarbon, etc., to transport oxygen. It is effective, but lacks tumor specificity. In an effort to integrate the merits of the two approaches, we designed a multifunctional nanoemulsion system named CCIPN and prepared it using a sonication-phase inversion composition-sonication method with orthogonal optimization. CCIPN included catalase, the methyl ester of 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO-Me), photosensitizer IR780, and perfluoropolyether. Perfluoropolyether may reserve the oxygen generated by catalase within the same nanoformulation for PDT. CCIPN contained spherical droplets below 100 nm and showed reasonable cytocompatibility. It presented a stronger ability to generate cytotoxic reactive oxygen species and consequently destroy tumor cells upon light irradiation, in comparison with its counterpart without catalase or perfluoropolyether. This study contributes to the design and preparation of oxygen-supplementing PDT nanomaterials.