Photostability Highly Improved Nanoparticles Based on IR-780 and Negative Charged Copolymer for Enhanced Photothermal Therapy

Enhanced Intracellular IR780 Delivery by Acidity-Triggered PEG-Detachable Hybrid Nanoparticles to Augment Photodynamic and Photothermal Combination Therapy for Melanoma Treatment

The PEGylation of drug-carrying nanoparticles has often been used to prolong blood circulation and improve drug deposition at tumor sites. Nevertheless, the PEG-rich hydrophilic surfaces retard the release of the payloads and internalization of therapeutic nanoparticles by cancer cells, thus lowering the anticancer efficacy. To boost the anticancer potency of the combined photodynamic therapy (PDT) and photothermal therapy (PTT) against melanoma by conquering the PEG dilemma, herein, the hybrid PEGylated chitosan-covered polydopamine (PDA) nanoparticles (PCPNs) with acidity-elicited PEG detachment ability were fabricated as carriers of IR780, a small-molecule photosensitizer used for PTT and PDT. The IR780@PCPNs displayed a uniform, solid-like spherical shape and sound colloidal stability. Under near-infrared (NIR) irradiation, the IR780@PCPNs showed prominent photothermal conversion efficiency (ca. 54.6%), robust photothermal stability, reduced IR780 photobleaching, sufficient singlet oxygen (1O2) production, and glutathione-depleting ability. Moreover, with the environmental pH being reduced from 7.4 to 5.0 at 37 °C, the decreased interactions between IR780 and PCPNs due to the increased protonation of phenolic hydroxyl residues within PDA and primary amine groups of chitosan accelerated the release of IR780 species from IR780@PCPNs. Importantly, the cellular uptake of IR780@PCPNs by B16F10 melanoma was remarkably promoted in a weakly acidic milieu upon PEG detachment driven by the disintegration of acid-labile benzoic imine. With NIR irradiation, the internalized IR780@PCPNs generated hyperthermia and 1O2 to damage mitochondria, thereby effectively inhibiting the proliferation of B16F10 cells. Collectively, our findings present a practical strategy for amplifying the anticancer efficacy of PTT combined with PDT using PEG-detachable IR780@PCPNs.

Targeting and structural engineering of light-responsive nanoprobes for hierarchical therapy: construction, optimization, and applications in cancer stem cells

Cancer stem cells (CSCs) possess the ability to self-renew and exhibit high differentiation potential, and they have been proven to be responsible for the maintenance, growth, and metastasis of tumors. As such, accurate identification and targeted therapy for CSCs are of great importance in clinical treatment. Here, a dual-targeted and light-responsive nanoprobe is presented, utilizing the reconstructed mesoporous SiO2 of a binary fatty acid eutectic mixture and a gold porous shell. The gold shell in the nanoprobe sustains a large absorption cross-section, providing a robust photothermal treatment effect against CSCs upon NIR irradiation. The photothermal effect simultaneously melts the eutectic mixture, which acted as the gating material, triggering the release of nuclear-targeted photosensitizers for photodynamic therapy (PDT). Additionally, to improve the hypoxic environment during PDT, hemoglobin (Hb) is conjugated to the nanoprobe using disulfide as a cross-linker, which can consume cellular glutathione while releasing Hb to deliver oxygen for PDT. Under the synergistic effect of photothermal therapy (PTT) and PDT, cytoplasmic organelles and intranuclear genetic materials are hierarchically damaged, initiating a cascade of reactions, including evident endoplasmic reticulum stress and inflammation. These responses, in turn, promote stem cell death and inhibit tumorigenicity. Furthermore, machine learning models, including random forest (FR), CatBoost, XGBoost, and LightGBM, were employed to optimize the reaction conditions for maximizing the synergistic effect, with CatBoost achieving the best performance. Additionally, antibody-conjugated nanoprobes effectively targeted colon cancer stem cells, demonstrating enhanced phototoxicity and the potential to suppress tumorsphere formation. Therefore, this dual-targeting nanoprobe demonstrates outstanding therapeutic integration performance and shows promise as a platform for synergistic PTT/PDT therapy of CSCs.

Targeted nanoparticle delivery unleashes synergistic photothermal and immunotherapeutic effects against hepatocellular carcinoma

The substantial mortality and morbidity of hepatocellular carcinoma, representing 90% of liver cancers, poses a significant health burden. The effectiveness of traditional hepatocellular carcinoma treatments such as surgical resection, radiotherapy, and chemotherapy is limited, underscoring the need for innovative therapeutic strategies. To this end, we synthesized phthalyl-pullulan nanoparticles encapsulating IR780 (an NIR-responsive heptamethine cyanine dye) and R848 (resiquimod; a TLR7/8 agonist) (PIR NPs). Characterization confirmed the size and loading capacity of PIR NPs, and controlled release of R848 therefrom upon NIR irradiation, thereby establishing the potential of this versatile therapeutic tool. PIR NPs were readily taken up by Hepa 1-6 cells in vitro by targeting asialoglycoprotein receptors present on its cellular surface. In in vivo experiments combining photothermal therapy and immunotherapy, following the local near-infrared irradiation, the PIR NPs accumulated in tumor sites induced immunogenic cell death and activated a tumor-specific T-cell immune response, thus highlighting their potent antitumor efficacy. The combined efficacy of photothermal therapy and immunotherapy presents a promising avenue for addressing the shortcomings of traditional hepatocellular carcinoma interventions. This study contributes valuable insights into the development of more effective and targeted therapeutic approaches for hepatocellular carcinoma treatment.

Recent progress on near-infrared fluorescence heptamethine cyanine dye-based molecules and nanoparticles for tumor imaging and treatment

Recenly, near-infrared fluorescence heptamethine cyanine dyes have shown satisfactory values in bioengineering, biology, and pharmacy especially in cancer diagnosis and treatment, owing to their excellent fluorescence property and biocompatibility. In order to achieve broad application prospects, diverse structures, and chemical properties of heptamethine cyanine dyes have been designed to develop novel functional molecules and nanoparticles over the past decade. For fluorescence and photoacoustic tumor imaging properties, heptamethine cyanine dyes are equipped with good photothermal performance and reactive oxygen species production properties under near-infrared light irradiation, thus holding great promise in photodynamic and/or photothermal cancer therapies. This review offers a comprehensive scope of the structures, comparisons, and applications of heptamethine cyanine dyes-based molecules as well as nanoparticles in tumor treatment and imaging in current years. Therefore, this review may drive the development and innovation of heptamethine cyanine dyes, significantly offering opportunities for improving tumor imaging and treatment in a precise noninvasive manner. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Transmissible H-aggregated NIR-II fluorophore to the tumor cell membrane for enhanced PTT and synergistic therapy of cancer

Photothermal therapy (PTT) combined with second near-infrared (NIR-II) fluorescence imaging (FI) has received increasing attention owing to its capacity for precise diagnosis and real-time monitoring of the therapeutic effects. It is of great clinical value to study organic small molecular fluorophores with both PTT and NIR-II FI functions. In this work, we report a skillfully fluorescent lipid nanosystem, the RR₉ (RGDRRRRRRRRRC) peptide-coated anionic liposome loaded with organic NIR-II fluorophore IR-1061 and chemotherapeutic drug carboplatin, which is named RRIALP-C4. According to the structural interaction between IR-1061 and phospholipid bilayer demonstrated by molecular dynamics simulations, IR-1061 is rationally designed to possess the H-aggregated state versus the free state, thus rendering RRIALP-C4 with the activated dual-channel integrated function of intravital NIR-II FI and NIR-I PTT. Functionalization of RRIALP-C4 with RR₉ peptide endows the specifically targeting capacity for α_vβ₃-overexpressed tumor cells and, more importantly, allows IR-1061 to transfer the H-aggregated state from liposomes to the tumor cell membrane through enhanced membrane fusion, thereby maintaining its PTT effect in tumor tissues. In vivo experiments demonstrate that RRIALP-C4 can effectively visualize tumor tissues and systemic blood vessels with a high sign-to-background ratio (SBR) to realize the synergistic treatment of thermochemotherapy by PTT synergistically with temperature-sensitive drug release. Therefore, the strategy of enhanced PTT through H-aggregation of NIR-II fluorophore in the tumor cell membrane has great potential for developing lipid nanosystems with integrated diagnosis and treatment function.

pH-Activatable Organic Nanoparticles for Efficient Low-Temperature Photothermal Therapy of Ocular Bacterial Infection

Low-temperature photothermal therapy (PTT) systems constructed by integrating organic photothermal agents with other bactericidal components that initiate bacterial apoptosis at low hyperthermia possess a promising prospect. However, these multicomponent low-temperature PTT nanoplatforms have drawbacks in terms of the tedious construction process, suboptimal synergy effect of diverse antibacterial therapies, and high laser dose needed, compromising their biosafety in ocular bacterial infection treatment. Herein, a mild PTT nanotherapeutic platform is formulated via the self-assembly of a pH-responsive phenothiazinium dye. These organic nanoparticles with photothermal conversion efficiency up to 84.5% necessitate only an ultralow light dose of 36 J/cm² to achieve efficient low-temperature photothermal bacterial inhibition at pH 5.5 under 650 nm laser irradiation. In addition, this intelligent mild photothermal nanoplatform undergoes negative to positive charge reversion in acid biofilms, exhibiting good penetration and highly efficient elimination of drug-resistant E. coli biofilms under photoirradiation. Further in vivo animal tests demonstrated efficient bacterial elimination and inflammatory mitigation as well as superior biocompatibility and biosafety of the photothermal nanoparticles in ocular bacterial infection treatment. Overall, this efficient single-component mild PTT system featuring simple construction processes holds great potential for wide application and clinical transformation.

Molecularly engineered carrier-free co-delivery nanoassembly for self-sensitized photothermal cancer therapy

BACKGROUND

Photothermal therapy (PTT) has been extensively investigated as a tumor-localizing therapeutic modality for neoplastic disorders. However, the hyperthermia effect of PTT is greatly restricted by the thermoresistance of tumor cells. Particularly, the compensatory expression of heat shock protein 90 (HSP90) has been found to significantly accelerate the thermal tolerance of tumor cells. Thus, a combination of HSP90 inhibitor and photothermal photosensitizer is expected to significantly enhance antitumor efficacy of PTT through hyperthermia sensitization. However, it remains challenging to precisely co-deliver two or more drugs into tumors.

METHODS

A carrier-free co-delivery nanoassembly of gambogic acid (GA, a HSP90 inhibitor) and DiR is ingeniously fabricated based on a facile and precise molecular co-assembly technique. The assembly mechanisms, photothermal conversion efficiency, laser-triggered drug release, cellular uptake, synergistic cytotoxicity of the nanoassembly are investigated in vitro. Furthermore, the pharmacokinetics, biodistribution and self-enhanced PTT efficacy were explored in vivo.

RESULTS

The nanoassembly presents multiple advantages throughout the whole drug delivery process, including carrier-free fabrication with good reproducibility, high drug co-loading efficiency with convenient dose adjustment, synchronous co-delivery of DiR and GA with long systemic circulation, as well as self-tracing tumor accumulation with efficient photothermal conversion. As expected, HSP90 inhibition-augmented PTT is observed in a 4T1 tumor BALB/c mice xenograft model.

CONCLUSION

Our study provides a novel and facile dual-drug co-assembly strategy for self-sensitized cancer therapy.

Red fluorescent pyrazoline-BODIPY nanoparticles for ultrafast and long-term bioimaging

Fluorescence bioimaging is very significant in studying biological processes. Fluorescent nanoparticles (NPs) manufactured from aggregation-induced emission (AIE) materials, as promising candidates, have attracted more attention. However, it is still a challenge to explore suitable AIE NPs for bioimaging. Herein, we synthesized pyrazoline-BODIPY (PZL-BDP) with a donor and acceptor (D-A) structure by a condensation reaction, cultured its single crystal, and studied its twisted intramolecular charge transfer (TICT) and AIE effects. PZL-BDP could self-assemble to form red fluorescent nanoparticles (PZL-BDP NPs) which showed a good fluorescence quantum yield of 15.8% in water. PZL-BDP NPs with excellent stability and biocompatibility exhibited a large Stokes shift (Δλ = 111 nm) which resulted in the reduction of external interference and enhancement of the fluorescence contrast. Furthermore, these nanoparticles could be readily internalized by HeLa cells and they stain the cells in just five seconds, indicating an ultrafast bioimaging protocol. Moreover, long-term tracking fluorescence signals in vivo for about 12 days were obtained. The bright red fluorescence, ultrafast cell staining ability, and long-term in vivo tracking competence outline the great potential of rational design nanomaterials with AIE characteristics for monitoring biological processes.

Highly efficient near-infrared BODIPY phototherapeutic nanoparticles for cancer treatment

A highly efficient NIR BODIPY nano-photosensitizer constructed by multi-intersection effects provides beneficial guidance for photodynamic and photothermal therapy.

Improvement of Photostability and NIR Activity of Cyanine Dye through Nanohybrid Formation: Key Information from Ultrafast Dynamical Studies

Near-infrared (NIR) light harvesting has enormous importance for different potential applications in the modern era of research. Some NIR cyanine dyes such as IR820 have achieved great success in energy harvesting and cancer therapy. However, their action is limited for low photostability, considerable thermal degradation, short circulation times, and nonspecific biodistribution. Our present study is an attempt to overcome such limitations by attaching a model cyanine dye IR820 with ZnO nanoparticles. We prepared an IR820-ZnO nanohybrid and characterized it using microscopic and optical spectroscopic tools. Thermogravimetric analysis depicted greater thermal stability of the IR820-ZnO nanohybrid compared to free dye. We explored the enhancement in the photostability of IR820 upon nanohybrid formation. We detected generation of photoinduced reactive oxygen species (ROS) such as superoxide, singlet oxygen, and so forth using appropriate molecular probes. The formation of IR820-ZnO nanohybrid reduced production of photoinduced singlet oxygen. However, it revealed an alternative trend in overall ROS formation (increases total ROS) under red light illumination. To correlate the enhanced photostability of IR820 on the ZnO surface, we explored excited-state dynamical processes at the interface in nanohybrids. We illustrated the photoinduced excited-state electron-transfer process from the lowest unoccupied molecular orbital of IR820 to the conduction band of ZnO. This photoelectron-transfer process enhances the production of ROS and decreases the formation of singlet oxygen that altogether leads to improvement in photostability and overall activity. A quencher of singlet oxygen sodium azide (NaN₃) was used to further confirm the direct association of singlet oxygen generation with the photostability issue of IR820. Also, ZnO is able to deliver the dye selectively in acidic environment, which suggests its diseased site-specific targeted activity. Our results provide promising improvement for potential use of IR820 through formation of a nanohybrid that could be translated for other NIR cyanine dyes.

Comparative study of two near-infrared coumarin–BODIPY dyes for bioimaging and photothermal therapy of cancer

Herein, two novel NIR coumarin BODIPYs with different conjugation degrees were comparatively investigated for photothermal therapy and fluorescence bioimaging.