Gold Nanospheres-Stabilized Indocyanine Green as a Synchronous Photodynamic-Photothermal Therapy Platform That Inhibits Tumor Growth and Metastasis

Tailoring Indocyanine Green J-Aggregates for Imaging, Cancer Phototherapy, and Drug Delivery: A Review

Indocyanine green J-aggregates (ICG-Jagg) have emerged as a significant subject of interest in biomedical applications due to their unique optical properties, tunable size, and excellent biocompatibility. This comprehensive review aims to provide an in-depth exploration of ICG-Jagg, with a focus on elucidating the diverse facets of their preparation and the factors that influence the preparation process. Additionally, the review discusses their applications in biomedical diagnostics, such as imaging and contrast agents, as well as their utilization in drug delivery and various phototherapeutic interventions.

Carrier-free chemo-phototherapeutic nanomedicines with endo/lysosomal escape function enhance the therapeutic effect of drug molecules in tumors

Carrier-free nanomedicines offer advantages of extremely high drug loading capacity (>80%), minimal non-drug constituent burden, and facile preparation processes. Numerous studies have proved that multimodal cancer therapy can enhance chemotherapy efficiency and mitigate multi-drug resistance (MDR) through synergistic therapeutic effects. Upon penetration into the tumor matrix, nanoparticles (NPs) are anticipated to be uptaken by cancer cells, primarily through clathrin-meditated endocytosis pathways, leading to their accumulation in endosomes/lysosomes within cells. However, endo/lysosomes exhibit a highly degradative environment for organic NPs and drug molecules, often resulting in treatment failure. Hence, this study designed a lysosomal escape mechanism with carrier-free nanomedicine, combining the chemotherapeutic drug, curcumin (Cur), and the photothermal/photodynamic therapeutic drug, indocyanine green (ICG), for synergistic cancer treatment (ICG-Cur NPs) via a facile preparation process. To facilitate endo/lysosomal escape, ICG-Cur NPs were modified with metal-phenolic networks (MPNs) of different thickness. The results indicate that a thick MPN coating promotes rapid endo/lysosomal escape of ICG-Cur NPs within 4 h and enhances the photothermal conversion efficiency of ICG-Cur NPs by 55.8%, significantly improving anticancer efficacy in both chemo- and photo-therapies within 3D solid tumor models. This finding underscores the critical role of endo/lysosomal escape capacity in carrier-free drug NPs for therapeutic outcomes and offers a facile solution to achieve it.

Recent advances in photothermal nanomaterials-mediated detection of circulating tumor cells

Photothermal materials have shown great potential for cancer detection and treatment due to their excellent photothermal effects. Circulating tumor cells (CTCs) are tumor cells that are shed from the primary tumor into the blood and metastasize. In contrast to other tumor markers that are free in the blood, CTCs are a collective term for all types of tumor cells present in the peripheral blood, a source of tumor metastasis, and clear evidence of tumor presence. CTCs detection enables early detection, diagnosis and treatment of tumors, and plays an important role in cancer prevention and treatment. This review summarizes the application of various photothermal materials in CTC detection, including gold, carbon, molybdenum, phosphorus, etc. and describes the significance of CTC detection for early tumor diagnosis and tumor prognosis. Focus is also put on how various photothermal materials play their roles in CTCs detection, including CT, imaging and photoacoustic and therapeutic roles. The physicochemical properties, shapes, and photothermal properties of various photothermal materials are discussed to improve the detection sensitivity and efficiency and to reduce the damage to normal cells. These photothermal materials are capable of converting radiant light energy into thermal energy for highly-sensitive CTCs detection and improving their photothermal properties by various methods, and have achieved good results in various experiments. The use of photothermal materials for CTCs detection is becoming more and more widespread and can be of significant help in early cancer screening and later treatment.

Chiral cysteine-copper ion-based assemblies for improved phototherapy

Phototherapy, encompassing photothermal therapy and photodynamic therapy, is gaining attention as an appealing cancer treatment modality. To enhance its clinical implementation, a comprehensive exploration of the pivotal factors influencing phototherapy is warranted. In this study, the L/d-cysteine (Cys)-copper ion (Cu2+) chiral nanoparticles, through the assembly of L/d-Cys-Cu2+ coordination complexes, were constructed. We found that these nanoparticles interacted with chiral liposomes in a chirality-dependent manner, with d-Cys-Cu2+ nanoparticles exhibiting more than three times stronger binding affinity than l-Cys-Cu2+ nanoparticles. Furthermore, we demonstrated that the d-Cys-Cu2+ nanoparticles were more efficiently internalized by Hela cells in contrast with l-Cys-Cu2+. On this basis, indocyanine green (ICG), acting as both photothermal and photodynamic agent, was encapsulated into L/d-Cys-Cu2+ nanoparticles. Experimental results showed that the l-Cys-Cu2+-ICG and d-Cys-Cu2+-ICG nanoparticles displayed almost identical photothermal performance and singlet oxygen (1O2) generation capability in aqueous solution. However, upon laser irradiation, the d-Cys-Cu2+-ICG nanoparticles achieved enhanced anti-tumor effects compared to l-Cys-Cu2+-ICG due to their chirality-promoted higher cellular uptake efficiency. These findings highlight the crucial role of chirality in phototherapy and provide new perspectives for engineering cancer therapeutic agents.

Universal Chiral-Plasmon-Induced Upward and Downward Transfer of Circular Dichroism to Achiral Molecules

Electromagnetic chirality transfer represents an effective means of the nanoscale manipulation of optical chirality. While most of the previous reports have exclusively focused on the circular dichroism (CD) transfer from UV-responsive chiral molecules toward visible-resonant achiral colloidal nanoparticles, here we demonstrate a reverse process in which plasmonic chirality can be transferred to achiral molecules, either upward from visible to UV or downward from visible to near infrared (NIR). By hybridizing achiral UV- or NIR-responsive dye molecules with chiral metal nanoparticles in solution, we observe a chiral-plasmon-induced CD (CPICD) signal at the intrinsically achiral molecular absorption bands. Full-wave electromagnetic modeling reveals that both near-field Coulomb interaction and far-field radiative coupling contribute to the observed CPICD, indicating that the mechanism considered here is universal for different material systems and types of optical resonances. Our study provides a set of design guidelines for broadband nanophotonic chiral sensing from the UV to NIR spectral regime.

NIR-Triggered Thermosensitive Nanoreactors for Dual-Guard Mechanism-Mediated Precise and Controllable Cancer Chemo-Phototherapy

Thermosensitive nanoparticles can be activated by externally applying heat, either through laser irradiation or magnetic fields, to trigger the release of drug payloads. This controlled release mechanism ensures that drugs are specifically released at the tumor site, maximizing their effectiveness while minimizing systemic toxicity and adverse effects. However, its efficacy is limited by the low concentration of drugs at action sites, which is caused by no specific target to tumor sties. Herein, hyaluronic acid (HA), a gooey, slippery substance with CD44-targeting ability, was conjugated with a thermosensitive polymer poly(acrylamide-co-acrylonitrile) to produce tumor-targeting and thermosensitive polymeric nanocarrier (HA-P) with an upper critical solution temperature (UCST) at 45 °C, which further coloaded chemo-drug doxorubicin (DOX) and photosensitizer Indocyanine green (ICG) to prepare thermosensitive nanoreactors HA-P/DOX&ICG. With photosensitizer ICG acting as the "temperature control element", HA-P/DOX&ICG nanoparticles can respond to temperature changes when receiving near-infrared irradiation and realize subsequent structure depolymerization for burst drug release when the ambient temperature was above 45 °C, achieving programmable and on-demand drug release for effective antitumor therapy. Tumor inhibition rate increased from 61.8 to 95.9% after laser irradiation. Furthermore, the prepared HA-P/DOX&ICG nanoparticles possess imaging properties, with ICG acting as a probe, enabling real-time monitoring of drug distribution and therapeutic response, facilitating precise treatment evaluation. These results provide enlightenment for the design of active tumor targeting and NIR-triggered programmable and on-demand drug release of thermosensitive nanoreactors for tumor therapy.

Near-infrared light activatable niosomes loaded with indocyanine green and plasmonic gold nanorods for theranostic applications

Light-mediated theranostic platforms involve the use of agents (small molecules/nanomaterials), which can absorb light to produce either heat or reactive chemical species (RCS) and emit fluorescence. Such platforms are advantageous in the field of personalized medicine, as they provide enhanced diagnostic capabilities, improved therapeutic efficiencies, and can also simultaneously monitor the treatment outcomes using imaging modalities. Specifically, agents absorbing near-infrared (NIR) light can provide minimal scattering, low autofluorescence, superior spatio-temporal resolution, and deeper tissue penetration depths. Gold nanorods (GNR) and indocyanine green (ICG) are two agents known to absorb light in the NIR region. GNR can provide tunable plasmonic properties, while ICG is an FDA-approved NIR fluorophore. However, the use of ICG and GNR suffers from various limitations, such as photobleaching, non-specificity, toxicity, and aggregation in solution. To overcome these limitations, herein, we report on NIR light-activatable niosomes loaded with GNR and ICG for cancer theranostic applications. Both agents were encapsulated into non-ionic surfactant-based biocompatible niosomes to form ICG-GNR@Nio with superior loading efficiencies and enhanced properties. ICG-GNR@Nio offers excellent storage stability, photostability, elevated temperature rise and generation of reactive oxygen species (ROS) upon 1064 nm laser irradiation. Subsequently, the enhanced phototherapeutic capabilities mediated by ICG-GNR@Nio were validated in the in vitro cellular experiments. Overall, ICG-GNR@Nio-based theranostic platforms can provide a significant benchmark in the improved diagnosis and therapeutic capabilities for biomedical clinicians to tackle various diseases.

Near-infrared photodynamic and photothermal co-therapy based on organic small molecular dyes

Near-infrared (NIR) organic small molecule dyes (OSMDs) are effective photothermal agents for photothermal therapy (PTT) due to their advantages of low cost and toxicity, good biodegradation, and strong NIR absorption over a wide wavelength range. Nevertheless, OSMDs have limited applicability in PTT due to their low photothermal conversion efficiency and inadequate destruction of tumor regions that are nonirradiated by NIR light. However, they can also act as photosensitizers (PSs) to produce reactive oxygen species (ROS), which can be further eradicated by using ROS-related therapies to address the above limitations of PTT. In this review, the synergistic mechanism, composition, and properties of photodynamic therapy (PDT)-PTT nanoplatforms were comprehensively discussed. In addition, some specific strategies for further improving the combined PTT and PDT based on OSMDs for cancer to completely eradicate cancer cells were outlined. These strategies include performing image-guided co-therapy, enhancing tumor infiltration, increasing H2O2 or O2 in the tumor microenvironment, and loading anticancer drugs onto nanoplatforms to enable combined therapy with phototherapy and chemotherapy. Meanwhile, the intriguing prospects and challenges of this treatment modality were also summarized with a focus on the future trends of its clinical application.

Positive Chemotaxis of CREKA-Modified Ceria@Polydopamine Biomimetic Nanoswimmers for Enhanced Penetration and Chemo-photothermal Tumor Therapy

Tumor interstitial pressure represents the greatest barrier against drug diffusion into the depth of the tumor. Biometric nanomotors highlight the possibility of enhanced deep penetration and improve cellular uptake. However, control of their directionality remains difficult to achieve. Herein, we report cysteine-arginine-glutamic acid-lysine-alanine (CREKA)-modified ceria@polydopamine nanobowls as tumor microenvironment-fueled nanoscale motors for positive chemotaxis into the tumor depth or toward tumor cells. Upon laser irradiation, this nanoswimmer rapidly depletes the tumor microenvironment-specific hydrogen peroxide (H2O2) in the nanobowl, contributing to a self-generated gradient and subsequently propulsion (9.5 μm/s at 46 °C). Moreover, the asymmetrical modification of CREKA on nanobowls could automatically reconfigure the motion direction toward tumor depth or tumor cells in response to receptor-ligand interaction, leading to a deep penetration (70 μm in multicellular spheroids) and enhanced antitumor effects over conventional nanomedicine-induced chemo-photothermal therapy (tumor growth inhibition rate: 84.2% versus 56.9%). Thus, controlling the direction of nanomotors holds considerable potential for improved antitumor responses, especially in solid tumors with high tumor interstitial pressure.

Medical Applications and Advancement of Near Infrared Photosensitive Indocyanine Green Molecules

Indocyanine green (ICG) is an important kind of near infrared (NIR) photosensitive molecules for PTT/PDT therapy as well as imaging. When exposed to NIR light, ICG can produce reactive oxygen species (ROS), which can kill cancer cells and pathogenic bacteria. Moreover, the absorbed light can also be converted into heat by ICG molecules to eliminate cancer cells. In addition, it performs exceptionally well in optical imaging-guided tumor therapy and antimicrobial therapy due to its deeper tissue penetration and low photobleaching properties in the near-infrared region compared to other dyes. In order to solve the problems of water and optical stability and multi-function problem of ICG molecules, composite nanomaterials based on ICG have been designed and widely used, especially in the fields of tumors and sterilization. So far, ICG molecules and their composite materials have become one of the most famous infrared sensitive materials. However, there have been no corresponding review articles focused on ICG molecules. In this review, the molecular structure and properties of ICG, composite material design, and near-infrared light- triggered anti-tumor, and antibacterial, and clinical applications are reviewed in detail, which of great significance for related research.

Buccal mucosal application of dissolvable microneedle patch containing photosensitizer provides effective localized delivery and phototherapy against oral carcinoma

The effectiveness of phototherapy using photosensitizers is limited by the challenges in their delivery at the site of irradiation. Here, we demonstrate the localized application of a photosensitizer-loaded microneedle patch for effective photodynamic and photothermal therapy in oral carcinoma. Indocyanine green (ICG) was studied as a photosensitizer for its effect on oral carcinoma, FaDu cells. Different parameters including concentration, near-infrared (NIR) laser irradiation intensity and irradiation time were optimized while measuring temperature increase and reactive oxygen species (ROS) generation in FaDu cells. A dissolvable microneedle (DMN) patch made of sodium carboxymethyl cellulose and sodium alginate was fabricated by the micromolding technique. DMN showed sufficient mechanical strength for insertion in the excised porcine buccal mucosa. DMN dissolved within 30 s in phosphate buffer and 30 min in the excised buccal mucosa. Confocal microscopy studies revealed DMN penetration up to a depth of 300 µm within the buccal mucosa. ICG-DMN applied on the back of the rat was found to be localized at the application site before and after irradiation using an 808 nm NIR laser. ICG-DMN was applied on the FaDu xenografted tumor model in athymic nude mice. The localized temperature increase and ROS generation significantly (P<0.05) decreased the tumor volume after ICG-DMN application compared with the control group. In conclusion, DMN can be developed for the localized administration of photosensitizers for phototherapy in oral carcinoma.

Combined Black Phosphorus Nanosheets with ICG/aPDT is an Effective Anti-Inflammatory Treatment for Periodontal Disorders

Introduction

Antibacterial photodynamic treatment (aPDT) has indispensable significance as a means of treating periodontal disorders because of its extraordinary potential for killing pathogenic bacteria by generating an overpowering amount of reactive oxygen species (ROS). The elevated ROS that may result from the antibacterial treatment procedure, however, could exert oxidative pressure inside periodontal pockets, causing irreparable damage to surrounding tissue, an issue that has severely restricted its medicinal applications. Accordingly, herein, we report the use of black phosphorus nanosheets (BPNSs) that can eliminate the side effects of ROS-based aPDT as well as scavenge ROS to produce an antibacterial effect.

Methods

The antibacterial effect of ICG/aPDT was observed by direct microscopic colony counting. A microplate reader and confocal microscope enabled measurements of cell viability and the quantification of ROS fluorescence. BPNS administration regulated the oxidative environment. IL-1β, IL-6, TNF-α, IL-10, TGF-β, and Arg-1 mRNA expression levels were used to assess the inflammatory response after BPNS treatment. In vivo, the efficacy of the combination of BPNSs and ICG/aPDT was evaluated in rats with periodontal disease by histomorphometric and immunohistochemical analyses.

Results

The CFU assay results verified the antibacterial effect of ICG/aPDT treatment, and ROS fluorescence quantification by CLSM indicated the antioxidative ability of the BPNSs. IL-1β, IL-6, TNF-α, IL-10, TGF-β, and Arg-1 mRNA expression levels were significantly decreased after BPNS treatment, confirming the in vitro anti-inflammatory effect of this nanomaterial. The histomorphometric and immunohistochemical analyses showed that the levels of proinflammatory factors decreased, suggesting that the BPNSs had anti-inflammatory effects in vivo.

Conclusion

Treatment with antioxidative BPNSs gives new insights into future anti-inflammatory therapies for periodontal disease and other infection-related inflammatory illnesses and provides an approach to combat the flaws of aPDT.

Nanotechnology-Based siRNA Delivery Systems to Overcome Tumor Immune Evasion in Cancer Immunotherapy

Immune evasion is a common reason causing the failure of anticancer immune therapy. Small interfering RNA (siRNA), which can activate the innate and adaptive immune system responses by silencing immune-relevant genes, have been demonstrated to be a powerful tool for preventing or reversing immune evasion. However, siRNAs show poor stability in biological fluids and cannot efficiently cross cell membranes. Nanotechnology has shown great potential for intracellular siRNA delivery in recent years. Nano-immunotherapy can efficiently penetrate the tumor microenvironment (TME) and deliver multiple immunomodulatory agents simultaneously, which appears to be a promising method for combination therapy. Therefore, it provides a new perspective for siRNA delivery in immunomodulation and cancer immunotherapy. The current advances and challenges in nanotechnology-based siRNA delivery strategies for overcoming immune evasion will be discussed in this review. In addition, we also offer insights into therapeutic options, which may expand its applications in clinical cancer treatment.

Emerging Strategies in Enhancing Singlet Oxygen Generation of Nano-Photosensitizers Toward Advanced Phototherapy

The great promise of photodynamic therapy (PDT) has thrusted the rapid progress of developing highly effective photosensitizers (PS) in killing cancerous cells and bacteria. To mitigate the intrinsic limitations of the classical molecular photosensitizers, researchers have been looking into designing new generation of nanomaterial-based photosensitizers (nano-photosensitizers) with better photostability and higher singlet oxygen generation (SOG) efficiency, and ways of enhancing the performance of existing photosensitizers. In this paper, we review the recent development of nano-photosensitizers and nanoplasmonic strategies to enhance the SOG efficiency for better PDT performance. Firstly, we explain the mechanism of reactive oxygen species generation by classical photosensitizers, followed by a brief discussion on the commercially available photosensitizers and their limitations in PDT. We then introduce three types of new generation nano-photosensitizers that can effectively produce singlet oxygen molecules under visible light illumination, i.e., aggregation-induced emission nanodots, metal nanoclusters (< 2 nm), and carbon dots. Different design approaches to synthesize these nano-photosensitizers were also discussed. To further enhance the SOG rate of nano-photosensitizers, plasmonic strategies on using different types of metal nanoparticles in both colloidal and planar metal-PS systems are reviewed. The key parameters that determine the metal-enhanced SOG (ME-SOG) efficiency and their underlined enhancement mechanism are discussed. Lastly, we highlight the future prospects of these nanoengineering strategies, and discuss how the future development in nanobiotechnology and theoretical simulation could accelerate the design of new photosensitizers and ME-SOG systems for highly effective image-guided photodynamic therapy.

Extracellular vesicles with high dual drug loading for safe and efficient combination chemo-phototherapy

Extracellular vesicles (EVs) have emerged as biocompatible nanocarriers for efficient delivery of various therapeutic agents, with intrinsic long-term blood circulatory capability and low immunogenicity. Here, indocyanine green (ICG)- and paclitaxel (PTX)-loaded EVs [EV(ICG/PTX)] were developed as a biocompatible nanoplatform for safe and efficient cancer treatment through near-infrared (NIR) light-triggered combination chemo/photothermal/photodynamic therapy. High dual drug encapsulation in EVs was achieved for both the hydrophilic ICG and hydrophobic PTX by simple incubation. The EVs substantially improved the photostability and cellular internalization of ICG, thereby augmenting the photothermal effects and reactive oxygen species production in breast cancer cells upon NIR light irradiation. Hence, ICG-loaded EVs activated by NIR light irradiation showed greater cytotoxic effects than free ICG. EV(ICG/PTX) showed the highest anticancer activity owing to the simultaneous chemo/photothermal/photodynamic therapy when compared with EV(ICG) and free ICG. In vivo study revealed that EV(ICG/PTX) had higher accumulation in tumors and improved pharmacokinetics compared to free ICG and PTX. In addition, a single intravenous administration of EV(ICG/PTX) exhibited a considerable inhibition of tumor proliferation with negligible systemic toxicity. Thus, this study demonstrates the potential of EV(ICG/PTX) for clinical translation of combination chemo-phototherapy.

The Applications of Gold Nanoparticles in the Diagnosis and Treatment of Gastrointestinal Cancer

In recent years, the morbidity and mortality of gastrointestinal cancer have remained high in China. Due to the deep location of the gastrointestinal organs, such as gastric cancer, the early symptoms of cancer are not obvious. It is generally discovered at an advanced stage with distant metastasis and lymph node infiltration, making it difficult to cure. Therefore, there is a significant need for novel technologies that can effectively diagnose and treat gastrointestinal cancer, ultimately reducing its mortality. Gold nanoparticles (GNPs), a type of nanocarrier with unique optical properties and remarkable biocompatibility, have the potential to influence the fate of cancer by delivering drugs, nucleic acids to cancer cells and tissues. As a safe and reliable visualization agent, GNPs can track drugs and accurately indicate the location and boundaries of cancer, opening up new possibilities for cancer treatment. In addition, GNPs have been used in photodynamic therapy to deliver photosensitizers, as well as in combination with photothermal therapy. Therefore, GNPs can be used as a safe and effective nanomaterial in the treatment and diagnosis of gastrointestinal cancer.

Iodinated cyanine dye-based nanosystem for synergistic phototherapy and hypoxia-activated bioreductive therapy

Photodynamic therapy (PDT) has been applied in cancer treatment by utilizing reactive oxygen species (ROS) to kill cancer cells. However, the effectiveness of PDT is greatly reduced due to local hypoxia. Hypoxic activated chemotherapy combined with PDT is expected to be a novel strategy to enhance anti-cancer therapy. Herein, a novel liposome (LCT) incorporated with photosensitizer (PS) and bioreductive prodrugs was developed for PDT-activated chemotherapy. In the design, CyI, an iodinated cyanine dye, which could simultaneously generate enhanced ROS and heat than other commonly used cyanine dyes, was loaded into the lipid bilayer; while tirapazamine (TPZ), a hypoxia-activated prodrug was encapsulated in the hydrophilic nucleus. Upon appropriate near-infrared (NIR) irradiation, CyI could simultaneously produce ROS and heat for synergistic PDT and photothermal therapy (PTT), as well as provide fluorescence signals for precise real-time imaging. Meanwhile, the continuous consumption of oxygen would result in a hypoxia microenvironment, further activating TPZ free radicals for chemotherapy, which could induce DNA double-strand breakage and chromosome aberration. Moreover, the prepared LCT could stimulate acute immune response through PDT activation, leading to synergistic PDT/PTT/chemo/immunotherapy to kill cancer cells and reduce tumor metastasis. Both in vitro and in vivo results demonstrated improved anticancer efficacy of LCT compared with traditional PDT or chemotherapy. It is expected that these iodinated cyanine dyes-based liposomes will provide a powerful and versatile theranostic strategy for tumor target phototherapy and PDT-induced chemotherapy.

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.

Optical-Property-Enhancing Novel Near-Infrared Active Niosome Nanoformulation for Deep-Tissue Bioimaging

Indocyanine green (ICG) is a clinically approved near-infrared (NIR) contrast agent used in medical diagnosis. However, ICG has not been used to its fullest for biomedical imaging applications due to its low fluorescence quantum yield, aqueous instability, concentration-dependent aggregation, and photo and thermal degradations, leading to quenching of its fluorescence emission. In the present study, a nanosized niosomal formulation, ICGNiosomes (ICGNios), is fabricated to encapsulate and protect ICG from degradation. Interestingly, compared to free ICG, the ICGNios exhibited higher fluorescence quantum yield and fluorescence emission with a bathochromic shift. Also, ICGNios nanoparticles are biocompatible, biodegradable, and readily uptaken by the cells. Furthermore, ICGNios show more enhanced fluorescence intensity through ∼1 cm thick chicken breast tissue compared to free ICG, which showed minimal emission through the same thickness of tissue. Our results suggest that ICGNios could offer a promising platform for deep-tissue NIR in vivo imaging to visualize inaccessible tissue microstructures for disease diagnosis and therapeutics.

New-generation photosensitizer-anchored gold nanorods for a single near-infrared light-triggered targeted photodynamic-photothermal therapy

Traditional combined photodynamic and photothermal therapy (PDT/PTT) was limited in clinical treatment of cancer due to the exceptionally low drug delivery efficiency to tumor sites and the activation by laser excitation with different wavelengths. We have accidentally discovered that our synthesized chlorin e6-C-15-ethyl ester (HB, a new type of photosensitizer) be activated by a laser with an excitation wavelength of 660 nm. Herein, we utilized Au nanorods (AuNRs) as 660 nm-activated PTT carriers to be successively surface-functionalized with HB and tumor-targeting peptide cyclic RGD (cRGD) to develop HB-AuNRs@cRGD for single NIR laser-induced targeted PDT/PTT. The HB-AuNRs@cRGD could be preferentially accumulated within tumor sites and rapidly internalized by cancer cells. Thereby, the HB-AuNRs@cRGD could exhibit amplified therapeutic effects by producing both significant reactive oxygen species (ROS) and hyperthermia simultaneously under the guidance of fluorescence imaging. The tumor inhibition rate on ECA109 esophageal cancer model was approximately 77.04%, and the negligible systematic toxicity was observed. This study proposed that HB-AuNRs@cRGD might be a promising strategy for single NIR laser-induced and imaging-guided targeted bimodal phototherapy.

Photodynamic Therapy for Pancreatic Ductal Adenocarcinoma

Simple Summary

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal of human cancers. Numerous clinical trials evaluating various combinations of chemotherapy and targeted agents and radiotherapy have failed to provide meaningful improvements in survival. A growing number of studies however have indicated that photodynamic therapy (PDT) may be a viable approach for treatment of some pancreatic tumors. PDT, which uses light to activate a photosensitizing agent in target tissue, has seen widespread adoption primarily for dermatological and other applications where superficial light delivery is relatively straightforward. Advances in fiber optic light delivery and dosimetry however have been leveraged to enable PDT even for challenging internal sites, including the pancreas. The aim of this article is to help inform future directions by reviewing relevant literature on the basic science, current clinical status, and potential challenges in the development of PDT as a treatment for PDAC.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal of human cancers. Clinical trials of various chemotherapy, radiotherapy, targeted agents and combination strategies have generally failed to provide meaningful improvement in survival for patients with unresectable disease. Photodynamic therapy (PDT) is a photochemistry-based approach that enables selective cell killing using tumor-localizing agents activated by visible or near-infrared light. In recent years, clinical studies have demonstrated the technical feasibility of PDT for patients with locally advanced PDAC while a growing body of preclinical literature has shown that PDT can overcome drug resistance and target problematic and aggressive disease. Emerging evidence also suggests the ability of PDT to target PDAC stroma, which is known to act as both a barrier to drug delivery and a tumor-promoting signaling partner. Here, we review the literature which indicates an emergent role of PDT in clinical management of PDAC, including the potential for combination with other targeted agents and RNA medicine.

Laser/GSH-Activatable Oxaliplatin/Phthalocyanine-Based Coordination Polymer Nanoparticles Combining Chemophotodynamic Therapy to Improve Cancer Immunotherapy

There are two severe obstacles in cancer immunotherapy. The first is that the low response rate challenges the immune response owing to the immunosuppressive tumor microenvironment (ITM) and poor immunogenicity of the tumor. The second obstacle is that the dense and intricate pathophysiology barrier seriously restricts deep drug delivery in solid tumors. A laser/glutathione (GSH)-activatable nanosystem with tumor penetration for achieving highly efficient immunotherapy is reported. The core of the nanosystem was synthesized by coordinating zinc ions with GSH-activatable oxaliplatin (OXA) prodrugs and carboxylated phthalocyanine. Such an OXA/phthalocyanine-based coordination polymer nanoparticle (OPCPN) was wrapped by a phospholipid bilayer and NTKPEG. NTKPEG is a PEGylated indoleamine 2,3-dioxygenase 1 (IDO1) inhibitor prodrug containing a thioketal (TK) linker, which was modified on the OPCPN (OPCPN@NTKPEG). Upon the laser irradiation tumor site, ROS production of the OPCPN@NTKPEG triggers cleavage of NTKPEG by degradation of TK for promoted tumor penetration and uptake. OXA, phthalocyanine, and IDO1 inhibitor were released by the intracellular high-level GSH. OXA inhibits cell growth and is combined with photodynamic therapy (PDT) to induce immunogenic cell death (ICD). The IDO1 inhibitor reversed the ITM by suppressing IDO1-mediated Trp degradation and exhaustion of cytotoxic T cells. Laser/GSH-activatable drug delivery was more conducive to enhancing ICD and reversing ITM in deep tumors. Chemo-PDT with OPCPN@NTKPEG significantly regressed tumor growth and reduced metastasis by improved cancer immunotherapy.

Cancer-cell-biomimetic Upconversion nanoparticles combining chemo-photodynamic therapy and CD73 blockade for metastatic triple-negative breast cancer

Photodynamic therapy (PDT) and chemotherapy show clinical promise in destroying orthotopic tumors but are insufficient against abscopal metastases. The research reports the combined application of an anti-CD73 antibody and chemo-PDT to synergistically amplify the anti-metastatic effects of T cell-mediated antitumor immunity. The cancer cell membrane (CM)-cloaked upconversion nanoparticles, integrating rose bengal (RB) and the reactive oxygen species (ROS)-sensitive polymer polyethylene glycol-thioketal-doxorubicin (PEG-TK-DOX, i.e., PTD), are tailored for near-infrared (NIR)-triggered chemo-PDT. CM camouflage enables nanoparticles' excellent tumor-targeting abilities and immune escape from macrophages. The combination of PDT and chemotherapy presents strong synergistic antitumor efficacy and synchronously causes a series of immunogenic cell death (ICD), leading to tumor-specific immunity. The anti-CD73 antibody prevents the immunosuppression phenomenon in tumors by blocking the adenosine pathway, and it is emerging as a sufficient immune checkpoint blockade when combined with ICD-elicited tumor therapies. As cancer membrane camouflaged nanoparticles CM@UCNP-RB/PTD combined with anti-CD73 antibodies, synergistic efficacy of chemotherapy and PDT not only destroys the orthotopic tumors by DOX and cytotoxic ROS but also prevents abscopal tumor metastasis via inducing systemic cytotoxic T cell responses with CD73 blockade. This strategy is promising in curing metastatic triple-negative breast cancer in preclinical research.

Tumor-Targeting Multifunctional Nanoprobe for Enhanced Photothermal/Photodynamic Therapy of Liver Cancer

Numerous researchers have committed to the development of combined therapy strategies for tumors, since their use in the treatment of tumors has more ideal therapeutic outcomes. In the study, we designed and prepared gold nanostars with CD147 modified on the surface and then efficiently loaded a photosensitive drug IR820 to construct a multifunctional nanoprobe. Due to the protection effect of gold, the nanoprobe has oxygen/heat energy generation capability and can also efficiently deliver the loaded drugs inside the tumor cells. Moreover, the nanoprobe has excellent photothermal/photodynamic therapeutic outcomes. The observation by photoacoustic real-time imaging validated the outstanding tumor-targeting characteristics of our nanoprobe. Finally, in the in vivo treatment experiment, the nanoprobe achieved ideal tumor-suppressive effects after the photothermal/photodynamic therapy. In summary, the findings of this experiment are useful in the development of new combined tumor therapy strategies based on nanomaterials.

Antibacterial Activity of Porous Gold Nanocomposites via NIR Light-Triggered Photothermal and Photodynamic Effects

Phototherapeutic approaches, including photothermal therapy (PTT) and photodynamic therapy (PDT), have become a promising strategy to combat microbial pathogens and tackle the crisis brought about by antibiotic-resistant strains. Herein, porous gold nanoparticles (AuPNs) were synthesized as photothermal agents and loaded with indocyanine green (ICG), a common photosensitizer for PDT, to fabricate a nanosystem presenting near-infrared (NIR) light-triggered synchronous PTT and PDT effects. The AuPNs can not only convert NIR light into heat with a high photothermal conversion efficiency (50.6-68.5%), but also provide a porous structure to facilely load ICG molecules. The adsorption of ICG onto AuPNs was mainly driven by electrostatic and hydrophobic interactions with the surfactant layer of AuPNs, and the aggregate state of ICG significantly enhanced its generation of reactive oxygen species. Moreover, taking advantage of its synergistic PTT and PDT effect, the hybrid nanocomposites displayed a remarkable antibacterial effect to the gram-positive pathogen Staphylococcus aureus (S. aureus) upon 808 nm laser irradiation.

Enhanced Photothermal-Photodynamic Therapy by Indocyanine Green and Curcumin-Loaded Layered MoS2 Hollow Spheres via Inhibition of P-Glycoprotein

PURPOSE

P-glycoprotein (P-gp), which is highly expressed in liver cancer cells, is one of the obstacles for the treatment of cancer. In this study, we have prepared and characterized a kind of novel ICG&Cur@MoS2 (ICG and Cur represent indocyanine green and curcumin, respectively) nanoplatform, which can achieve photothermal-photodynamic therapy and inhibit the P-gp effectively and safely.

METHODS

In this work, plenty of studies including drug release, acute toxicity, Western blot, real-time PCR, cell viability, therapeutic experiment in vivo, immunofluorescence and so on were conducted to test the antitumor potential of ICG&Cur@MoS2 and the inhibitory effect of curcumin on P-gp.

RESULTS

The ICG&Cur@MoS2 NPs exhibit an excellent photothermal effect and relatively low toxicity. Cell viability in the ICG&Cur@MoS2 + NIR group was significantly lower than that in ICG@MoS2 + NIR group (75.3% vs 81.2%, 59.0% vs 64.4%, 20.3% vs 27.5%, and 15.4% vs 22.3%) at the concentration of ICG at 0.5, 5, 25, 50 μg/mL (P<0.05 at each concentration). Western blot, Q-PCR, and immunofluorescence assay indicate ICG&Cur@MoS2 NPs can inhibit the P-gp effectively and safely. In vivo, the tumors in the ICG@MoS2 + NIR group are significantly smaller than those in the MoS2 + NIR group (95.0 vs 420.9 mm3, p<0.05).

CONCLUSION

In conclusion, we have successfully synthesized ICG&Cur@MoS2 nanoparticles which can not only achieve PTT-PDT but also inhibit P-gp effectively. Our findings indicate that the PTT-PDT exhibits great potential in the treatment of hepatocellular carcinoma. Meanwhile, ICG&Cur@MoS2 can effectively inhibit the expression of P-gp, which will enhance the PDT effect.

Photosensitizer Nanoparticles Boost Photodynamic Therapy for Pancreatic Cancer Treatment

Patients with pancreatic cancer (PCa) have a poor prognosis apart from the few suitable for surgery. Photodynamic therapy (PDT) is a minimally invasive treatment modality whose efficacy and safety in treating unresectable localized PCa have been corroborated in clinic. Yet, it suffers from certain limitations during clinical exploitation, including insufficient photosensitizers (PSs) delivery, tumor-oxygenation dependency, and treatment escape of aggressive tumors. To overcome these obstacles, an increasing number of researchers are currently on a quest to develop photosensitizer nanoparticles (NPs) by the use of a variety of nanocarrier systems to improve cellular uptake and biodistribution of photosensitizers. Encapsulation of PSs with NPs endows them significantly higher accumulation within PCa tumors due to the increased solubility and stability in blood circulation. A number of approaches have been explored to produce NPs co-delivering multi-agents affording PDT-based synergistic therapies for improved response rates and durability of response after treatment. This review provides an overview of available data regarding the design, methodology, and oncological outcome of the innovative NPs-based PDT of PCa.

Construction of pH/glutathione responsive chitosan nanoparticles by a self-assembly/self-crosslinking method for photodynamic therapy

A novel pH/glutathione (GSH) multi-responsive chitosan nanoparticles (NPs) material has been successfully designed and prepared by a self-assembly/self-crosslinking method for photodynamic therapy (PDT), which overcomes the shortcomings of traditional photosensitizer carriers, such as poor chemical stability, low loading efficiency and single-responsive photosensitizer release. Amphiphilic sulfhydryl chitosan (SA-CS-NAC) is first prepared by modifying chitosan (CS) with stearic acid (SA) and N-acetyl-L-cysteine (NAC), and then subject to self-assembly and self-crosslinking in the presence of photosensitizer, indocyanine green (ICG), to form the ICG-loaded amphiphilic sulfhydryl chitosan nanoparticles (SA-CS-NAC@ICG NPs). The ICG entrapment efficiency and loading efficiency of the NPs are found to be 95.2% and 27.6%, respectively. The multi-responsive ICG release of the NPs to the low pH and high GSH content of the microenvironment in tumor cells is successfully achieved. Under the laser irradiation, the SA-CS-NAC@ICG NPs produce the amount of reactive oxygen species (ROS) twice of that generated by free ICG under the same conditions. The in vitro cell experiment confirmed the strong cellular uptake ability, low biotoxicity and good tumor inhibition of the NPs. Our work has provided a new strategy for the targeted photosensitizer delivery for PDT.

ICG-loaded gold nano-bipyramids with NIR activatable dual PTT-PDT therapeutic potential in melanoma cells

A great amount of effort is directed towards the progress of cancer treatment approaches aspiring to develop non-invasive, targeted and highly efficient therapies. In this context, Photothermal (PTT) and Photodynamic (PDT) Therapies were proven as promising. This work aims to integrate the therapeutic activities of two near-infrared (NIR) photoactive biomaterials - gold nano-bipyramids (AuBPs) and Indocyanine Green (ICG) - into one single targeted hybrid nanosystem able to operate as dual PTT-PDT agent with higher efficiency compared with each one alone. Firstly, different aspect ratio' AuBPs were systematically investigated in water solution for their intrinsic ability to efficiently generate toxic reactive oxygen species, namely oxygen singlet (¹O₂), under NIR laser irradiation, as this effect is less investigated in literature. Interestingly, the photodynamic activity of AuBPs measured by monitoring the photooxidation of 9,10-Anthracenediyl-bis(methylene)dimalonic acid (ABDA) - a well-known ¹O₂ sensor, is important, counting for 30 % decrease in ABDA optical absorbance for the most active AuBPs, well-correlating with the previously determined photothermal conversion efficiency. Furthermore, ICG was successfully grafted onto the Poly-lactic acid (PLA) coating of plasmonic nanoparticles and, consequently, the as-designed fully integrated hybrid nanosystem shows improved PTT-PDT performance in solution. Specifically, by triggering simultaneous PTT-PDT activities, the ¹O₂ amount is doubled, while the heating monitoring shows higher and faster increase in temperature compared to AuBPs alone. Finally, the efficiency of the combined PTT-PDT therapeutic activity was validated in vitro against B16-F10 cell line by covalent conjugation of the nanosystem with Folic Acid, which ensures the cellular recognition by overexpression of folate receptor.

Design and Fabrication of Dual Redox Responsive Nanoparticles with Diselenide Linkage Combined Photodynamically to Effectively Enhance Gene Expression

BACKGROUND

PEI is currently the most used non-viral gene carrier and the transfection efficiency is closely related to the molecular weight; however, the prominent problem is that the cytotoxicity increased with the molecular weight.

METHODS

A novel redox responsive biodegradable diselenide cross-linked polymer (dPSP) was designed to enhance gene expression. ICG-pEGFP-TRAIL/dPSP nanoparticles with high drug loading are prepared, which have redox sensitivity and plasmid protection. The transfection efficiency of dPSP nanoparticle was evaluated in vitro.

RESULTS

The plasmid was compressed by 100% at the N/P ratio of 16, and the particle size was less than 100 nm. When explored onto high concentrations of GSH/H2O2, dPSP4 degraded into small molecular weight cationic substances with low cytotoxicity rapidly. Singlet oxygen (1O2) was produced when indocyanine green (ICG) was irradiated by near-infrared laser irradiation (NIR) to promote oxidative degradation of dPSP4 nanoparticles. Under the stimulation of NIR 808 and redox agent, the particle size and PDI of ICG-pDNA/dPSP nanoparticle increased significantly.

CONCLUSION

Compared with gene therapy alone, co-transportation of dPSP4 nanoparticle with ICG and pEGFP-TRAIL had better antitumor effect. Diselenide-crosslinked polyspermine had a promising prospect on gene delivery and preparation of multifunctional anti-tumor carrier.

Persistent Regulation of Tumor Hypoxia Microenvironment via a Bioinspired Pt-Based Oxygen Nanogenerator for Multimodal Imaging-Guided Synergistic Phototherapy

Multifunctional nanoplatforms for imaging-guided synergistic antitumor treatment are highly desirable in biomedical applications. However, anticancer treatment is largely affected by the pre-existing hypoxic tumor microenvironment (TME), which not only causes the resistance of the tumors to photodynamic therapy (PDT), but also promotes tumorigenesis and tumor progression. Here, a continuous O2 self-enriched nanoplatform is constructed for multimodal imaging-guided synergistic phototherapy based on octahedral gold nanoshells (GNSs), which are constructed by a more facile and straightforward one-step method using platinum (Pt) nanozyme-decorated metal-organic frameworks (MOF) as the inner template. The Pt-decorated MOF@GNSs (PtMGs) are further functionalized with human serum albumin-chelated gadolinium (HSA-Gd, HGd) and loaded with indocyanine green (ICG) (ICG-PtMGs@HGd) to achieve a synergistic PDT/PTT effect and fluorescence (FL)/multispectral optoacoustic tomography (MSOT)/X-ray computed tomography (CT)/magnetic resonance (MR) imaging. The Pt-decorated nanoplatform endows remarkable catalase-like behavior and facilitates the continuous decomposition of the endogenous H2O2 into O2 to enhance the PDT effect under hypoxic TME. HSA modification enhances the biocompatibility and tumor-targeting ability of the nanocomposites. This TME-responsive and O2 self-supplement nanoparticle holds great potential as a multifunctional theranostic nanoplatform for the multimodal imaging-guided synergistic phototherapy of solid tumors.

Natural Hydrogels Applied in Photodynamic Therapy

Natural hydrogels are three-dimensional (3D) water-retaining materials with a skeleton consisting of natural polymers, their derivatives or mixtures. Natural hydrogels can provide sustained or controlled drug release and possess some unique properties of natural polymers, such as biodegradability, biocompatibility and some additional functions, such as CD44 targeting of hyaluronic acid. Natural hydrogels can be used with photosensitizers (PSs) in photodynamic therapy (PDT) to increase the range of applications. In the current review, the pertinent design variables are discussed along with a description of the categories of natural hydrogels available for PDT.

CD271 antibody-functionalized HGNs for targeted photothermal therapy of osteosarcoma stem cells

Cancer stem cells (CSCs) are considered to maintain the vitality of tumor cell populations through self-renewal and infinite proliferation, but their accessibility is still under investigation. In addition, CSCs are more resistant to chemotherapy and radiotherapy compared with common tumor cells. This study aimed to develop a kind of novel and feasible nanomaterial for targeted photothermal ablation of osteosarcoma stem cells, which could be a promising anticancer strategy. The osteosarcoma stem cells were extracted by serum-free culture and we further verified the stem cell properties. We evaluated the expression of CD271 by flow cytometry. PEGylated multifunctional hollow gold nanospheres (HGNs) were prepared based on CD271 monoclonal antibody. Bifunctional SH-PEG-COOH was used to facilitate the covalent linkage between HGNs and antibody. The efficient uptake and distribution of the functionalized HGNs were investigated using ICP-MS and TEM. Morphological studies and quantitative apoptosis evaluation were performed to detect the effect of photothermal therapy (PTT). Afterwards, we explored the possible mechanism by which PTT induced targeted killing of cancer stem cells. Osteosarcoma cells isolated from serum-free culture were detected to show stem cell properties. CD271 was found to be a potential novel surface marker for osteosarcoma stem cells. By conjugating with CD271 monoclonal antibody, these biomimetic nanoparticles can be targeted and absorbed by osteosarcoma stem cells. HGNs-PEG-CD271 achieved excellent cell viability inhibition compared with non-targeted PEGylated HGNs upon near-infrared (NIR) laser irradiation. The mechanism of targeted killing may be related to the apoptosis pathway and DNA double-strand injuries. CD271 was considered to be a surface biomarker for osteosarcoma stem cells. Functionalized HGNs based on CD271 antibody exhibited excellent potential for targeted PTT, which may be a promising strategy for osteosarcoma treatment.

NIR-Triggered Sequentially Responsive Nanocarriers Amplified Cascade Synergistic Effect of Chemo-Photodynamic Therapy with Inspired Antitumor Immunity

A desirable cancer therapeutic strategy is supposed to have effective ability to not only exert maximum anticancer ability but also inspire antitumor immunity for preventing tumor relapse and metastasis. During this research, multifunctional upconversion nanoparticles (UCNPs) coated by ROS-responsive micelles are prepared for tumor targeting and near-infrared (NIR)-triggered photodynamic therapy (PDT)-combined synergistic effect of chemotherapy. Moreover, both PDT and chemotherapy agents could activate antitumor immunity via inducing immunogenic cell death with CD8⁺ and CD4⁺ T cells infiltrating in tumors. Through the experiments, intravenous administration of multifunctional nanocarriers with noninvasive NIR irradiation destroys the orthotopic tumors and efficiently suppresses lung metastasis in a metastatic triple-negative breast cancer model by cascade-amplifying chemo-PDT and systemic antitumor immunity. In conclusion, this study provides prospective chemo-PDT with inspired antitumor immunity for metastatic cancer treatment.

Targeted Antitumor Mechanism of C-PC/CMC-CD55sp Nanospheres in HeLa Cervical Cancer Cells

In vitro studies had shown that C-Phycocyanin (C-PC) inhibited cervical cancer HeLa cells growth. We constructed C-PC/CMC-CD55sp nanospheres using C-PC, Carboxymethyl Chitosan (CMC), and CD55 ligand peptide (CD55sp) to allow for targeted antitumor effects against HeLa cells in vitro and in vivo. The characteristics of the nanospheres were determined using FTIR, electron microscopy, and laser particle size analysis. Flow cytometry, laser confocal microscopy and small animal imaging system showed the targeting of C-PC/CMC-CD55sp nanospheres on HeLa cells. Subsequently, the proliferation and apoptosis were analyzed by Cell Counting Kit-8 (CCK-8), flow cytometry, TUNEL assay and electron microscopy. The expression of the apoptosis-related protein was determined using western blot. The stainings of Hematoxylin and Eosin (HE) were employed to evaluate the cell condition of tumor tissue sections. The cytokines in the blood in tumor-bearing nude mice was determined using ELISA. These results showed that C-PC/CMC-CD55sp nanospheres were successfully constructed and targeted HeLa cells. The constructed nanospheres were more effective than C-PC alone in inhibiting the proliferation and inducing apoptosis in HeLa cells. We also found that C-PC/CMC-CD55sp nanospheres had a significant inhibitory effect on the expression of antiapoptotic protein Bcl-2 and a promotion on the transformation of caspase 3 to cleaved caspase 3. C-PC/CMC-CD55sp nanospheres played an important role in tumor suppression, reduced the expression TGF-β, and increased IL-6 and TNF-α. This study demonstrates that the constructed new C-PC/CMC-CD55sp nanospheres exerted targeted antitumor effects in vivo and in vitro which provided a novel idea for application of C-PC, and provided experimental basis for comprehensive targeted treatment of tumors.

Broad spectrum antibacterial photodynamic and photothermal therapy achieved with indocyanine green loaded SPIONs under near infrared irradiation

Antimicrobial photodynamic therapy (aPDT) and antimicrobial photothermal therapy (aPTT) are promising local and effective alternative therapies for antibiotic resistant bacterial infections and biofilms.

Advanced Nanotechnology Leading the Way to Multimodal Imaging-Guided Precision Surgical Therapy

Surgical resection is the primary and most effective treatment for most patients with solid tumors. However, patients suffer from postoperative recurrence and metastasis. In the past years, emerging nanotechnology has led the way to minimally invasive, precision and intelligent oncological surgery after the rapid development of minimally invasive surgical technology. Advanced nanotechnology in the construction of nanomaterials (NMs) for precision imaging-guided surgery (IGS) as well as surgery-assisted synergistic therapy is summarized, thereby unlocking the advantages of nanotechnology in multimodal IGS-assisted precision synergistic cancer therapy. First, mechanisms and principles of NMs to surgical targets are briefly introduced. Multimodal imaging based on molecular imaging technologies provides a practical method to achieve intraoperative visualization with high resolution and deep tissue penetration. Moreover, multifunctional NMs synergize surgery with adjuvant therapy (e.g., chemotherapy, immunotherapy, phototherapy) to eliminate residual lesions. Finally, key issues in the development of ideal theranostic NMs associated with surgical applications and challenges of clinical transformation are discussed to push forward further development of NMs for multimodal IGS-assisted precision synergistic cancer therapy.

Indocyanine green loaded APTMS coated SPIONs for dual phototherapy of cancer

Superparamagnetic iron oxide nanoparticles (SPIONs) have been recently recognized as highly efficient photothermal therapy (PTT) agents. Here, we demonstrate, for the first time to our knowledge, dose and laser intensity dependent PTT potential of small, spherical, 3-aminopropyltrimethoxysilane coated cationic superparamagnetic iron oxide nanoparticles (APTMS@SPIONs) in aqueous solutions upon irradiation at 795 nm. Indocyanine green (ICG) which has been recently used for photodynamic therapy (PDT), was loaded to APTMS@SPIONs to improve the stability of ICG and to achieve an effective mild PTT and PDT (dual therapy) combination for synergistic therapeutic effect on cancer cells via a single laser treatment in the near infrared (NIR). Neither APTMS@SPIONs nor ICG-APTMS@SPIONs showed dark toxicity on MCF7 breast and HT29 colon cancer cell lines. A safe laser procedure was determined as 10 min irradiation at 795 nm with 1.8 W/cm² of laser intensity, at which APTMS@SPION did not cause a significant cell death. However, free ICG reduced cell viability at and above 10 μg/ml under these conditions along with generation of reactive oxygen species (ROS), more effectively in MCF7. ICG-APTMS@SPION treated cells showed 2-fold increase in ROS generation and near complete cell death at and below 5 μg/ml ICG dose, even in less sensitive HT29 cells after a single laser treatment at NIR, which would be safe for the healthy tissue and provide a longer penetration depth. Besides, both components can be utilized for diagnosis and the overall composition may be used for optical-image guided phototherapy in the NIR region.

Insight into the efficiency of oxygen introduced photodynamic therapy (PDT) and deep PDT against cancers with various assembled nanocarriers

Photodynamic therapy (PDT) has been used in the treatment of cancers and other benign diseases for several years in clinic. However, the hypoxia of tumors and the penetration limitation of excitation light to tissues can dramatically reduce the efficacy of PDT to cancers. To overcome these drawbacks, various assembled nanocarriers such as nanoparticles, nanocapsules, nanocrystals, and so on were introduced. The assembled nanocarriers have the ability of loading photosensitizers, delivering O₂ into tumors, generating O₂ in situ in tumors, as well as turning near-infrared (NIR) light, X-rays, and chemical energy into ultraviolet or visible light. Therefore, it is easy for the nanocarriers to improve the hypoxia microenvironment or increase the treatment depth of cancers, which will improve the efficiency of PDT to some degree. In recent years, a number of investigations were focused on these subjects. We will summarize the advances of nanocarriers in PDT, especially in O₂ introduction PDT and deep PDT. The perspectives, challenges, and potential in translation of PDT will also be discussed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Biology-Inspired Nanomaterials > Lipid-Based Structures Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

A tumor microenvironment responsive biodegradable CaCO3/MnO2- based nanoplatform for the enhanced photodynamic therapy and improved PD-L1 immunotherapy

The low efficiency of photodynamic therapy (PDT) is caused by tumor hypoxia and the adaptive immune resistance/evasion of tumor cells, while the currently emerging immune checkpoint therapy restores the intrinsic immune capacities but can't directly attack the tumor cells.

Methods: Herein we report an integrated nanoplatform that combines PDT with immunotherapy to enhance photodynamic therapeutic effects and simultaneously inhibit tumor cells resistance/evasion. To achieve this, we fabricated Mn@CaCO₃/ICG nanoparticles and loaded them with PD-L1-targeting siRNA.

Results: Thanks to the protection of CaCO₃ on the loaded ICG and the oxygen produced by MnO₂, an enhanced photodynamic therapeutic effect in vitro was observed. In vivo experiments demonstrated that the nanoplatform could efficiently deliver the loaded drug to the tumor tissues and significantly improve tumor hypoxia, which further contributes to the therapeutic effect of PDT in vivo. Moreover, the synergistic benefits derived from the siRNA, which silenced the checkpoint gene PD-L1 that mediates the immune resistance/evasion, resulted in a surprising therapeutic effect to rouse the immune system.

Conclusions: The combination treatment strategy has great potential to be developed as a new and robust method for enhanced PDT therapy with high efficiency and a powerful antitumor immune response based on PD-L1 blockade.

Targeting photodynamic and photothermal therapy to the endoplasmic reticulum enhances immunogenic cancer cell death

Immunogenic cell death (ICD)-associated immunogenicity can be evoked through reactive oxygen species (ROS) produced via endoplasmic reticulum (ER) stress. In this study, we generate a double ER-targeting strategy to realize photodynamic therapy (PDT) photothermal therapy (PTT) immunotherapy. This nanosystem consists of ER-targeting pardaxin (FAL) peptides modified-, indocyanine green (ICG) conjugated- hollow gold nanospheres (FAL-ICG-HAuNS), together with an oxygen-delivering hemoglobin (Hb) liposome (FAL-Hb lipo), designed to reverse hypoxia. Compared with non-targeting nanosystems, the ER-targeting naosystem induces robust ER stress and calreticulin (CRT) exposure on the cell surface under near-infrared (NIR) light irradiation. CRT, a marker for ICD, acts as an ‘eat me’ signal to stimulate the antigen presenting function of dendritic cells. As a result, a series of immunological responses are activated, including CD8⁺ T cell proliferation and cytotoxic cytokine secretion. In conclusion, ER-targeting PDT-PTT promoted ICD-associated immunotherapy through direct ROS-based ER stress and exhibited enhanced anti-tumour efficacy.

Reactive oxygen species induced by endoplasmic reitculum stress can be exploited for cancer therapy. Here, nanoparticles are targetted to the endoplasmic reticulum and, when accompanied by PDT, produce stress resulting in calreticulin exposure on the cell surface, which activates dendritic cells.

Bioinspired Multivalent Peptide Nanotubes for Sialic Acid Targeting and Imaging-Guided Treatment of Metastatic Melanoma

Tumor metastasis is considered a major cause of cancer-related human mortalities. However, it still remains a formidable challenge in clinics. Herein, a bioinspired multivalent nanoplatform for the highly effective treatment of the metastatic melanoma is reported. The versatile nanoplatform is designed by integrating indocyanine green and a chemotherapeutic drug (7-ethyl-10-hydroxycamptothecin) into phenylboronic acid (PBA)-functionalized peptide nanotubes (termed as I/S-PPNTs). I/S-PPNTs precisely target tumor cells through multivalent interaction between PBA and overexpressed sialic acid on the tumor surface in order to achieve imaging-guided combination therapy. It is demonstrated that I/S-PPNTs are efficiently internalized by the B16-F10 melanoma cells in vitro in a PBA grafting density-dependent manner. It is further shown that I/S-PPNTs specifically accumulate and deeply penetrate into both the subcutaneous and lung metastatic B16-F10 melanoma tumors. More importantly, I/S-PPNT-mediated combination chemo- and photodynamic therapy efficiently eradicates tumor and suppresses the lung metastasis of B16-F10 melanoma in an immunocompetent C57BL/6 mouse model. The results highlight the promising potential of the multivalent peptide nanotubes for active tumor targeting and imaging-guided cancer therapy.

"Navigate-dock-activate" anti-tumor strategy: Tumor micromilieu charge-switchable, hierarchically activated nanoplatform with ultrarapid tumor-tropic accumulation for trackable photothermal/chemotherapy

The delivery of therapeutics into tumors remains a challenge in nanoparticle-mediated drug delivery. However, effective therapies such as photothermal therapy (PTT) are limited by quick systemic clearance and non-specific biodistribution. Anti-tumor strategies tailored to accommodate both tumor accumulation/retention and cellular internalization under a single platform would be a promising strategy. This work demonstrates a hierarchical activating strategy that would exhibit enhanced circulation and rapid tumor-tropism as well as facilitate tumor penetration, followed by tumor-specific drug release to realize trackable photothermal/chemotherapy. Methods: We engineered a lithocholic acid-conjugated disulfide-linked polyethyleneimine micelle (LAPMi) loaded with paclitaxel (LAPMi-PTX, L), followed by the electrostatic adsorption of indocyanine green (ICG, I) on LAPMI-PTX and subsequently coated them with thermosensitive DPPC and DSPE-PEG-NH₂ lipids (L), producing Lipid/ICG/LAPMi-PTX (LIL-PTX) nanoparticles (NPs). The characteristics of NPs, including physicochemical characterization, photothermal & pH responsiveness, cell uptake, tumor spheroid penetration, anti-tumor efficacy and hierarchical activation of LIL-PTX NPs were investigated in vitro and in vivo by using CT26 cell line. The anti-metastatic potential of LIL-PTX NPs were demonstrated using 4T1 orthotopic tumor model. Results: The NPs synthesized possessed charge switchability in the mildly acidic pH, and were laser- and pH-responsive. Dual stimuli-responsive nature of LIL-PTX NPs improved the disposition of therapeutics to the tumor, reflected by enhanced intracellular uptake, tumor spheroid penetration and in vitro cytotoxicity studies. LIL-PTX NPs readily switched its surface charge from neutral to positive upon reaching the tumor milieu, thus resulting in rapid tumor tropism and accumulation. Under near-infrared laser irradiation, the thermosensitive lipids on LIL-PTX NPs were deshielded, and the tumor-penetrating LAPMi-PTX was subsequently exposed to the tumor milieu, thus resulting in enhanced intracellular internalization. Next, LAPMi-PTX evaded the endo-lysosomes, thereby releasing the PTX through the degradation of LAPMi mediated by intracellular GSH in the tumor. LIL-PTX NPs significantly improved the therapy by eradicating primary tumors completely and suppressing their subsequent lung metastasis. Conclusion: The improved therapeutic index is due to enhanced passive targeting by rapid tumor-tropic accumulation and tumor penetration by laser-driven exposure of LAPMi, thereby improving the therapeutic delivery for image-guided photothermal/chemotherapy.

Indocyanine green-modified hollow mesoporous Prussian blue nanoparticles loading doxorubicin for fluorescence-guided tri-modal combination therapy of cancer

Hollow mesoporous structures with interior cavities and expanded surface area have attracted considerable interest as drug delivery systems. In this study, a multifunctional nanotheranostic agent was developed by conjugating indocyanine green (ICG) and loading doxorubicin (DOX) onto the surfaces or within the cavities of hollow mesoporous Prussian blue (HMPB) nanoparticles, known as HMPB@PEI/ICG/DOX or simply HPID NPs, which were investigated as phototheranostic agents for in vivo fluorescence imaging and light-induced chemotherapy, photothermal therapy (PTT) and photodynamic therapy (PDT). These original HPID NPs exhibited strong near infrared (NIR) absorbance, reactive oxygen species (ROS) yield, and controlled chemotherapeutic drug release behavior. After intravenous injection of HPID NPs, highly efficient solid tumor ablation effects were observed in 4T1 tumor-bearing mouse models under NIR laser irradiation. Additionally, there was insignificant low-term toxicity or damage to normal tissues, as evidenced by histopathological and hemocompatibility analyses, suggesting that this agent has reliable biosafety for systemic applications. Taken together, the results of this study suggest that HPID NPs can produce tumor-specific and stimuli-triggered theranostic effects under tri-modal combination therapy. These HPID NPs advantageously provide traceable accumulation and activation and therefore could be a capable mediator in nanomedicines for eliminating solid tumors.

Artificially controlled degradable nanoparticles for contrast switch MRI and programmed cancer therapy

Background

Utilizing the permeability enhancement and irreversible biomolecule denaturation caused by hyperthermia, photothermal-chemo synergistic therapy has shown great potential in clinical cancer treatment.

Purpose

The objective of this study was to provide a novel controlled drug release method to improve the efficiency of photothermal-chemo synergistic therapy.

Patients and methods

HCT116 tumor-bearing mice were selected as modal for the study of cancer theranostics efficiency. The T2 to T1 magnetic resonance imaging contrast switch was studied in vivo. Analyses of the tumor growth of mice were carried out to evaluate the tumor therapy efficiency.

Results

We developed novel artificially controlled degradable Co₃O₄ nanoparticles and explored their potential in drug delivery/release. In the presence of ascorbic acid (AA), the designed nanomaterials can be degraded via a redox process and hence release the loaded drugs. Importantly, the AA, in the lack of l-gulonolactone oxidase, cannot be synthesized in the body of typical mammal including human, which suggested that the degradation process can be controlled artificially. Moreover, the obtained nanoparticles have outstanding photothermal conversion efficiency and their degradation can also result in an magnetic resonance imaging contrast enhancement switch from T₂ to T₁, which benefits the cancer theranostics.

Conclusion

Our results illustrated that the artificially controlled degradable nanoparticles can serve as an alternative candidate for controllable drug release as well as a platform for highly efficient photothermal-chemo synergistic cancer theranostics.