6-Aminocaproic acid as a linker to improve near-infrared fluorescence imaging and photothermal cancer therapy of PEGylated indocyanine green

A blood-brain barrier- and blood-brain tumor barrier-penetrating siRNA delivery system targeting gliomas for brain tumor immunotherapy

Glioma is recognized as the most infiltrative and lethal form of central nervous system tumors and is known for its limited response to standard therapeutic interventions, high recurrence rate, and unfavorable prognosis. Recent progress in gene and immunotherapy presents a renewed sense of optimism in the treatment of glioblastoma. However, the barriers to overcome include the blood-brain barrier (BBB) and the blood-brain tumor barrier (BBTB), as well as the suppressive immune microenvironment. Overcoming these barriers remains a significant challenge. Here, we developed a lipid nanoparticle platform incorporating a dual-functional peptide (cholesterol-DP7-ACP-T7-modified DOTAP or DAT-LNP) capable of targeting glioma across the BBB and BBTB for brain tumor immunotherapy. This system was designed to achieve two key functions. First, the system could effectively penetrate the BBB during accumulation within brain tissue following intravenous administration. Second, this system enhances the maturation of dendritic cells, the polarization of M1 macrophages, and the activation of cytotoxic CD8+ T cells. This multifaceted approach effectively mitigates the immunosuppressive tumor microenvironment of glioma and promotes robust antitumor immune responses. Overall, the intravenous administration of the delivery system designed in this study demonstrates significant therapeutic potential for glioma and holds promising applications in the field of cancer immunotherapy.

Research progress of organic photothermal agents delivery and synergistic therapy systems

Cancer is currently one of the leading causes of mortality worldwide. Due to the inevitable shortcomings of conventional treatments, photothermal therapy (PTT) has attracted great attention as an emerging and non-invasive cancer treatment method. Photothermal agents (PTAs) is a necessary component of PTT to play its role. It accumulates at the tumor site through appropriate methods and converts the absorbed light energy into heat energy effectively under near-infrared light irradiation, thus increasing the temperature of the tumor area and facilitating ablation of the tumor cells. Compared to inorganic photothermal agents, which have limitations such as non-degradability and potential long-term toxicity in vivo, organic photothermal agents exhibit excellent biocompatibility and biodegradability, thus showing promising prospects for the application of PTT in cancer treatment. And these organic photothermal agents can also be engineered into nanoparticles to improve their water solubility, extend their circulation time in vivo, and specifically target tumors. Moreover, further combination of PTT with other treatment methods can effectively enhance the efficacy of cancer treatment and alleviate the side effects associated with single treatments. This article briefly introduces several common types of organic photothermal agents and their nanoparticles, and reviews the applications of PTT based on organic photothermal agents in combination with chemotherapy, photodynamic therapy, chemodynamic therapy, immunotherapy, and multimodal combination therapy for tumor treatment, which expands the ideas and methods in the field of tumor treatment.

Enhanced stability and photothermal efficiency of Indocyanine Green J-aggregates by nanoformulation with Calix[4]arene for photothermal therapy of cancers

Photothermal therapy (PTT) is a method of growing attention, owing to its controllable process, high efficiency and minimal side effect. Indocyanine Green (ICG) is as Food and Drug Administration (FDA) approved agent that stands on the frontline of further developments of PTT toward clinics. However, the applicability of ICG-mediated PTT is limited by the rapid in vivo clearance and photo-degradation of ICG. To improve those parameters, nanosized ICG-loaded nanoparticles (ICG-J/CX) were fabricated in this study by co-assembly of anionic ICG J-aggregates (ICG-J) with cationic tetraguanidinium calix[4]arene (CX). This very simple approach produces ICG-J/CX with a well-defined nanometer range size and a close to neutral charge. The nanoparticles demonstrate high photothermal conversion efficiency (PCE) and dramatically improved photostability, as compared with ICG. The in vitro cellular uptake and cytotoxicity studies further demonstrated that the ICG-J/CX nanoparticles enhance uptake and photothermal efficiency in comparison with ICG or non-formulated ICG-J, overall demonstrating that ICG-J/CX mediated photothermal therapy have significant potential for attaining cancer treatment.

Sequential Diagnosis and Treatment for Colon Cancer via Derived Iridium and Indocyanine Green Hybrid Nanomicelles

Indocyanine green (ICG) has been widely explored for the theranostics of tumors. However, ICG mainly accumulates in the liver, spleen, or kidney in addition to in tumors, causing inaccurate diagnoses and impaired therapeutic effects under NIR irradiation. Herein, a hybrid nanomicelle was constructed by integrating hypoxia-sensitive iridium(III) and ICG for precise tumor localization and photothermal therapy in sequence. In this nanomicelle, the amphiphilic iridium(III) complex (BTPH)₂Ir(SA-PEG) was synthesized through the coordination substitution of hydrophobic (BTPH)₂IrCl₂ and hydrophilic PEGlyated succinylacetone (SA-PEG). Meanwhile, PEGlyated ICG (ICG-PEG) as a derivative of the photosensitizer ICG was also synthesized. (BTPH)₂Ir(SA-PEG) and ICG-PEG were coassembled by dialysis to form the hybrid nanomicelle M-Ir-ICG. Hypoxia-sensitive fluorescence, ROS generation, and the photothermal effect of M-Ir-ICG were investigated in vitro and in vivo. The experimental results indicated that M-Ir-ICG nanomicelles could locate at the tumor site first and then perform photothermal therapy with 83.90% TIR, demonstrating great potential for clinical applications.

Renal-Clearable Probe with Water Solubility and Photostability for Biomarker-Activatable Detection of Acute Kidney Injuries via NIR-II Fluorescence and Optoacoustic Imaging

Acute kidney injuries (AKI) have serious short-term or long-term complications with high morbidity and mortality rate, thus posing great health threats. Developing high-performance NIR-II probes for noninvasive in situ detection of AKI via NIR-II fluorescent and optoacoustic dual-mode imaging is of great significance. Yet NIR-II chromophores often feature long conjugation and hydrophobicity, which prevent them from being renal clearable, thus limiting their applications in the detection and imaging of kidney diseases. To fully exploit the advantageous features of heptamethine cyanine dye, while overcoming its relatively poor photostability, and to strive to design a NIR-II probe for the detection and imaging of AKI with dual-mode imaging, herein, we have developed the probe PEG3-HC-PB, which is renal clearable, water soluble, and biomarker activatable and has good photostability. As for the probe, its fluorescence (900-1200 nm) is quenched due to the existence of the electron-pulling phenylboronic group (responsive element), and it exhibits weak absorption with a peak at 830 nm. Meanwhile, in the presence of the overexpressed H₂O₂ in the renal region in the case of AKI, the phenylboronic group is converted to the phenylhydroxy group, which enhances NIR-II fluorescent emission (900-1200 nm) and absorption (600-900 nm) and eventually produces conspicuous optoacoustic signals and NIR-II fluorescent emission for imaging. This probe enables detection of contrast-agent-induced and ischemia/reperfusion-induced AKI in mice using real-time 3D-MSOT and NIR-II fluorescent dual-mode imaging via response to the biomarker H₂O₂. Hence, this probe can be used as a practicable tool for detecting AKI; additionally, its design strategy could provide insight into the design of other large-conjugation NIR-II probes with multifarious biological applications.

A Spiky Silver-Iron Oxide Nanoparticle for Highly Efficient Targeted Photothermal Therapy and Multimodal Imaging of Thrombosis

Thrombosis and its complications are responsible for 30% of annual deaths. Limitations of methods for diagnosing and treating thrombosis highlight the need for improvements. Agents that provide simultaneous diagnostic and therapeutic activities (theranostics) are paramount for an accurate diagnosis and rapid treatment. In this study, silver-iron oxide nanoparticles (AgIONPs) are developed for highly efficient targeted photothermal therapy and imaging of thrombosis. Small iron oxide nanoparticles are employed as seeding agents for the generation of a new class of spiky silver nanoparticles with strong absorbance in the near-infrared range. The AgIONPs are biofunctionalized with binding ligands for targeting thrombi. Photoacoustic and fluorescence imaging demonstrate the highly specific binding of AgIONPs to the thrombus when functionalized with a single chain antibody targeting activated platelets. Photothermal thrombolysis in vivo shows an increase in the temperature of thrombi and a full restoration of blood flow for targeted group but not in the non-targeted group. Thrombolysis from targeted groups is significantly improved (p < 0.0001) in comparison to the standard thrombolytic used in the clinic. Assays show no apparent side effects of AgIONPs. Altogether, this work suggests that AgIONPs are potential theranostic agents for thrombosis.

Enhancing Photothermal Therapy Efficacy by In Situ Self-Assembly in Glioma

The residence time of some small molecular imaging and therapeutic agents in tumor tissue is short and the molecules can be easily dispersed, which decreases treatment efficacy. Therefore, methods that enhance oncotherapy performance are of significant importance. Here, we report an in situ self-assembly strategy aimed at enhancing the photothermal therapy of glioblastomas. The probe, ICG-PEP-c(RGD)fk, consisted of a glutathione-reactive self-assembling polypeptide as the skeleton, indocyanine green (ICG) as a theranostic agent, and cyclic Arg-Gly-Asp [c(RGD)fk] peptides as the targeting group. ICG-PEP-c(RGD)fk was synthesized and found to be assembled in the glutathione environment at 9.446 μM in vitro. Human glioblastoma cell line U87MG-luc with high integrin αvβ3 expression was applied to invivo experiments. ICG-PEP-c(RGD)fk provided clearer tumor imaging and had a tumor retention time of 6.12 times longer than that of ICG-c(RGD)fk. In therapeutic experiments, ICG-PEP-c(RGD)fk significantly suppressed glioblastoma growth and the tumor volume was 2.61 times smaller than in the ICG-c(RGD)fk group at the end of the observation period. Moreover, the median survival time of ICG-PEP-c(RGD)fk group was significantly improved by 2.78 times compared with that of the control group. In conclusion, glutathione-reactive self-assembling peptides are capable of increasing the tumor retention time and improving the photothermal therapeutic effect. The in situ self-assembly strategy is a potential and feasible method to enhance oncotherapy.

A new chitosan-based thermosensitive nanoplatform for combined photothermal and chemotherapy

Targeting the delivery of anti-cancer drugs to a tumor site is essential for effective treatment and to ensure minimal damage to healthy cells and tissues. In this work, a chitosan-based nanoplatform was constructed for combined photothermal therapy and chemotherapy of breast cancer. The pH-sensitive and biocompatible biopolymer chitosan (CS) was grafted with N-vinylcaprolactam (NVCL) and modified with biotin (Bio), imparting it with temperature sensitive property and also the ability for active targeting. The polymer self-assembled to give nanoparticles (NPs) loaded with indocyanine green (ICG) and doxorubicin (DOX). When the NPs are exposed to near-infrared (NIR) laser irradiation, ICG converts the light to heat, inducing a significant phase transition in the NPs and facilitating the release of the drug cargo. In addition, the solubility of chitosan is increased in the slightly acidic microenvironment of the tumor site, which also promotes drug release. A detailed analysis of the NPs both in vitro and in vivo showed that the carrier system is biocompatible, while the drug-loaded NPs are selectively taken up by cancer cells. Particularly when augmented with NIR irradiation, this leads to potent cell death in vitro and also in an in vivo murine xenograft model of breast cancer.

Doxorubicin hydrochloride and L-arginine co-loaded nanovesicle for drug resistance reversal stimulated by near-infrared light

Drug resistance is accountable for the inadequate outcome of chemotherapy in clinics. The newly emerging role of nitric oxide (NO) to conquer drug resistance has been recognized as a potential strategy. However, it remains a great challenge to realize targeted delivery as well as accurate release of NO at desired sites. Herein, we developed a PEGylated indocyanine green (mPEG-ICG) integrated nanovesicle system (PIDA) to simultaneously load doxorubicin hydrochloride (DOX⋅HCl) and the NO donor L-arginine (L-Arg), which can produce NO triggered by NIR light irradiation and exert multimodal therapy to sensitize drug-resistant cancers. Upon 808 nm irradiation, the NO released from PIDA led to a decrease in mitochondrial membrane potential, an increase in ROS and significant ATP depletion in K562/ADR cells, thus inhibiting cell growth and resolving the problem of drug resistance. Consequently, the in vivo experiment on K562/ADR-bearing nude mice indicated that PIDA nanovesicles achieved significant anticancer efficacy with a tumor inhibition rate of 80.8%. Above all, PIDA nanovesicles offer guidance for designing nanoplatforms for drug-resistant cancer treatment.

A highly efficient polydopamine encapsulated clinical ICG theranostic nanoplatform for enhanced photothermal therapy of cervical cancer

Photothermal therapy (PTT) is a safe and efficient anti-tumor treatment. A photothermal agent (PTA) with good biocompatibility and strong photothermal properties is of great importance for PTT. In this study, near-infrared (NIR) excitable clinical indocyanine green (ICG) was utilized as a PTA and further encapsulated by another PTA polydopamine (PDA) to form highly stable and efficient ICG@PDA nanoparticles (NPs). Then the ICG@PDA NPs were modified with methoxy polyethylene glycol amine (mPEG₂₀₀₀-NH₂) to form biocompatible ICG@PDA@PEG NPs. ICG@PDA@PEG NPs showed good water solubility and a spherical shape with an average size of 140 nm. Furthermore, the photothermal properties of ICG@PDA@PEG NPs were studied and excellent photothermal performance with a photothermal conversion efficiency of 43.7% under 808 nm laser irradiation was achieved. Then, the PTT properties of ICG@PDA@PEG NPs were confirmed on HeLa cells with an efficiency of 86.1%. Meanwhile, the in vivo biocompatibility and toxicity of ICG@PDA@PEG NPs were evaluated. No apparent in vivo toxicity was observed in 24 hours and 7 days. Next, in vivo PTT analysis was conducted for cervical tumor-bearing nude mice under 808 nm laser excitation. It showed a good anti-tumor effect in vivo. Thus, ICG@PDA@PEG NPs exhibited great potential for safe and efficient photothermal therapy in anti-tumor therapy.

Tumor-Targeting NIRF/MR Dual-Modal Molecular Imaging Probe for Surgery Navigation

Multimodality imaging recognized as a promising monitoring strategy can serve the needs of accurate diagnosis and treatment of cancer by providing molecular and anatomic information about tumor sites. However, the probes based on multiple imaging modalities for surgery navigation remain limited due to poor biocompatibility and tumor targeting specificity. Herein, we present a small-molecule near-infrared fluorescence/magnetic resonance (NIRF/MR) imaging probe, Gd-NMC-3, covalently coupled with DCDSTCY and Gd-DOTA via butane diamine, for precise detection and intraoperative visualization. The in vitro and in vivo studies demonstrated that Gd-NMC-3 could be effectively accumulated in tumor sites as a bimodal imaging molecule exhibiting significant fluorescence accumulation and reasonable relaxation property in tumors with low cytotoxicity and good biocompatibility. Furthermore, Gd-NMC-3 was successfully applied to provide real-time visual navigation in LM3 orthotopic and subcutaneous tumor models to guide the resection of tumors. Importantly, no more fluorescence was observed in mice after operation, implying the total removal of tumor tissues. In conclusion, Gd-NMC-3 has great potential to be applied in the clinic based on its high resolution and sensitivity in tumor imaging.

Near infrared light triggered ternary synergistic cancer therapy via L-arginine-loaded nanovesicles with modification of PEGylated indocyanine green

L-arginine (L-Arg) is an important nitric oxide (NO) donor, and its exploration in NO gas therapy has received widespread attention. Application of nano-platforms that can efficiently deliver L-Arg and induce its rapid conversion to NO becomes a predominant strategy to achieve promising therapeutic effects in tumor treatment. Herein, an enhanced nano-vesicular system of ternary synergistic treatment combining NO therapy, photodynamic therapy (PDT) along with mild photothermal therapy (MPTT) was developed for cancer therapy. We integrated photosensitizer PEGylated indocyanine green (mPEG-ICG) into polyphosphazene PEP nano-vesicles through co-assembly and simultaneously encapsulated NO donor L-Arg into the vesicle center chambers to form mPEG-ICG/L-Arg co-loaded system IA-PEP. The unique nanostructure of vesicle provided considerable loading capacity for mPEG-ICG and L-Arg with 15.9% and 17.95% loading content, respectively, and efficiently prevented mPEG-ICG and L-Arg from leaking. Significantly, the reactive oxygen species (ROS) was produced by IA-PEP under 808 nm laser irradiation to perform PDT against tumors, which concurrently reacted with L-Arg to release NO and arouse gas therapy effectively. Moreover, the mild heat produced by IA-PEP could exhibit cooperative anti-tumor effect with minimal damage. As a consequence, in vivo antitumor investigation on nude mice bearing xenograft MCF-7 tumors verified the potent anti-tumor efficacy of IA-PEP under 808 nm laser irradiation with complete tumor elimination. Taken together, the IA-PEP nano-vesicle system designed in this work may provide a promising treatment paradigm for synergistic cancer treatment. STATEMENT OF SIGNIFICANCE: Nitric oxide (NO) gas therapy has drawn widespread attention due to its "green" treatment paradigm with negligible side effects. L-arginine (L-Arg) is an important NO donor. However, how to efficiently deliver L-Arg and induce NO generation remains a big challenge since L-Arg is a water-soluble small molecule. Herein, we developed a nano-vesicle system IA-PEP to integrate photosensitizer PEGylated indocyanine green and L-Arg with high loading content and to produce a ternary synergistic treatment combining NO therapy, photodynamic therapy (PDT) along with mild-temperature photothermal therapy (MPTT) under 808 nm laser irradiation. The in vivo investigation on nude mice bearing xenograft MCF-7 tumors verified its potent anti-tumor efficacy with complete tumor elimination.

"Dual-functional" strontium titanate nanotubes designed based on fusion peptides simultaneously enhancing anti-infection and osseointegration

Currently, there is an increasing clinical demand for implants that effectively resist bacterial infections while promoting osseointegration. In this study, the fusion peptide technology was used to linearly fuse the antimicrobial peptide (AMP, HHC36) and the bone-promoting peptide (RGD), so that the titanium (Ti)-based implant modified by the polypeptide had the dual function of "antibacterial-promoting bone". Firstly, self-organized vertically-oriented strontium-doped titanium dioxide nanotubes (STN) were manufactured by anodizing and hydrothermal synthesis methods. Secondly, the fusion peptide (HHC36-RGD) was loaded into the tubular structure by a simple vacuum-assisted physical adsorption method. Finally, STN loaded with HHC36-RGD (H-R-STN) was obtained. The characterization results demonstrated that the surface of the H-R-STN had a roughness and hydrophilicity that promoted cell adhesion. Additionally, electrochemical tests showed that H-R-STN coating can reduce the corrosion rate of pure Ti. The fusion peptide and Sr²⁺ in H-R-STN were released in the initial fast and subsequent slow kinetic model. Expected, H-R-STN can kill more than 99% of clinically common pathogenic bacteria (Staphylococcus aureus and Escherichia coli), and significantly inhibit the formation of bacterial biofilms. Simultaneously, under the synergistic effect of RGD in the fusion peptide and strontium in STN, H-R-STN markedly promoted the adhesion and proliferation of mouse osteoblasts, and significantly promoted osteogenic markers (alkaline phosphatase, runt-related transcription, collagen, mineralization) expression. In summary, the bifunctional titanium-based implant constructed by H-R-STN in this article can effectively prevent bacterial infections and promote early osseointegration. The main advantage of the titanium surface treatment method of the study was that its simplicity, low cost, especially its versatility made it a promising anti-infective bone repair material.

Monodisperse ZIF-8@dextran nanoparticles co-loaded with hydrophilic and hydrophobic functional cargos for combined near-infrared fluorescence imaging and photothermal therapy

Impressive developments have been achieved with the use of zeolitic imidazolate framework-8 (ZIF-8) as nanocarriers for tumor theranostics in recent decades by incorporating imaging agents and therapeutic drugs within ZIF-8. However, the simultaneous immobilization of hydrophilic and hydrophobic functional molecules into ZIF-8 nanoparticles in water or organic solvents still presents a daunting challenge. Herein, we developed a new synthesis/encapsulation two-in-one (denoted as one-pot) approach to synthesize uniform dextran-modified Cy5.5&ICG@ZIF-8-Dex nanoparticles in DMSO/H₂O solvent mixtures, which enabled the simultaneous encapsulation of hydrophilic indocyanine green (ICG) and hydrophobic cyanine-5.5 (Cy5.5) during the same step. It was confirmed that the one-pot approach in this mixed solvents facilitated the loading of ICG and Cy5.5 molecules. Moreover, the encapsulation of Cy5.5 and ICG within ZIF-8 nanoparticles endowed them with fluorescence imaging capability and photothermal conversion capacity, respectively. The in vivo near-infrared (NIR) fluorescent images of A549-bearing mice injected with Cy5.5&ICG@ZIF-8-Dex demonstrated sufficient accumulations of Cy5.5 at tumor sites due to the enhanced permeability and retention effect. Most impressively, the fluorescent intensity of Cy5.5&ICG@ZIF-8-Dex at tumor site was approximately 40-fold higher than that of free Cy5.5. Additionally, the results of in vivo infrared imaging and photothermal therapy of Cy5.5&ICG@ZIF-8-Dex showed enhanced therapeutic efficiency in comparison with free ICG, further confirming its tumor-targeting capability and photothermal capacity. Therefore, this multifunctional system based on ZIF-8 nanocarriers offered a potential nanoplatform for tumor-targeting theranostics, thus broadening the synthesis and applications of ZIF-8 composite nanoparticles for NIR fluorescence imaging and photothermal therapy in the biomedical field. STATEMENT OF SIGNIFICANCE: Simultaneous immobilization of hydrophilic and hydrophobic molecules into ZIF-8 nanoparticles still remains a daunting challenge. Therefore, we have developed a new synthesis/encapsulation two-in-one approach to synthesize uniform Cy5.5&ICG@ZIF-8-Dex composite nanoparticles in DMSO/H₂O solvent mixtures, which enabled the simultaneous encapsulation of hydrophilic indocyanine green (ICG) and hydrophobic cyanine-5.5 (Cy5.5) functional molecules during a single step. The results showed that the co-loading of Cy5.5 and ICG within the ZIF-8 nanoparticles endowed them with a remarkable fluorescence imaging capability and photothermal conversion capacity. Based on their enhanced convenience and efficacy to simultaneously encapsulate hydrophilic and hydrophobic molecules, the multifunctional nanocarriers that were prepared in the DMSO/H₂O mixed solvents provide a potential nanoplatform toward fluorescence imaging and photothermal therapy for tumor theranostics.

Metal complexation-mediated stable and biocompatible nanoformulation of clinically approved near-infrared absorber for improved tumor targeting and photonic theranostics

Indocyanine green (ICG) is a clinically approved dye that has shown great promise as a phototheranostic material with fluorescent, photoacoustic and photothermal responses in the near-infrared region. However, it has certain limitations, such as poor photostability and non-specific binding to serum proteins, subjected to rapid clearance and decreased theranostic efficacy in vivo. This study reports stable and biocompatible nanoparticles of ICG (ICG-Fe NPs) where ICG is electrostatically complexed with an endogenously abundant metal ion (Fe3+) and subsequently nanoformulated with a clinically approved polymer surfactant, Pluronic F127. Under near-infrared laser irradiation, ICG-Fe NPs were found to be more effective for photothermal temperature elevation than free ICG molecules owing to the improved photostability. In addition, ICG-Fe NPs showed the markedly enhanced tumor targeting and visualization with photoacoustic/fluorescent signaling upon intravenous injection, attributed to the stable metal complexation that prevents ICG-Fe NPs from releasing free ICG before tumor targeting. Under dual-modal imaging guidance, ICG-Fe NPs could successfully potentiate photothermal therapy of cancer by applying near-infrared laser irradiation, holding potential as a promising nanomedicine composed of all biocompatible ingredients for clinically relevant phototheranostics.

Amphiphilic Diketopyrrolopyrrole Derivatives for Efficient Near-Infrared Fluorescence Imaging and Photothermal Therapy

The design and synthesis of single-molecule amphiphilic and multifunctional phototherapeutic agents are important to cancer diagnosis and therapy. In this work, we developed three amphiphilic diketopyrrolopyrrole derivatives (TPADPP, DTPADPP, and TPADDPP) with different donor-acceptor structures and poly(ethylene glycol) side chains. The corresponding nanoparticles (NPs) were obtained via a self-assembly from three amphiphilic DPP derivatives and used as smart phototherapeutic agents for tumor diagnosis and treatment. The three amphiphilic DPP NPs exhibited near-infrared (NIR) emissions and good biocompatibility. Thus, they could be used as fluorescence (FL) imaging agents for guided therapy. DTPADPP NPs and TPADDPP NPs also displayed excellent photothermal performance and high accumulation in the tumor. Owing to these beneficial features, the DTPADPP NPs and TPADDPP NPs synthesized herein are suitable for NIR FL imaging and effective photothermal therapy against the tumor in vivo.

Indocyanine Green-Based Theranostic Nanoplatform for NIR Fluorescence Image-Guided Chemo/Photothermal Therapy of Cervical Cancer

Purpose

Indocyanine green (ICG) is a favorable fluorescence nanoprobe for its strong NIR-I fluorescence emission and good photothermal capabilities. However, the stability and tumor targeting ability of ICG is poor, which limits its further applications. To further improve the photothermal and therapeutic efficiency of ICG, bovine serum albumin (BSA) was utilized to encapsulate the ICG and the chemotherapeutic drug doxorubicin (DOX) was loaded to form the BSA@ICG-DOX theranostic nanoplatform.

Methods

In this study, ICG-loaded BSA nanoparticles (NPs) and the BSA@ICG-DOX NPs were fabricated using reprecipitation methods. Next, the tumour inhibition ability and biocompatibility of the NPs were evaluated. A subcutaneous xenografted nude mice model was established and imaging guided synergetic therapy was performed with the assistance of BSA@ICG-DOX NPs under 808 nm laser irradiation.

Results

The BSA@ICG NPs exhibited strong NIR-I fluorescence emission, excellent photothermal properties, biocompatibility, and tumor targeting ability. To further improve the therapeutic efficiency, the chemotherapeutic drug doxorubicin (DOX) was loaded into the BSA@ICG NPs to form the BSA@ICG-DOX theranostic nanoplatform. The BSA@ICG-DOX NPs were spherical with an average size of ~194.7 nm. The NPs had high encapsulation efficiency (DOX: 19.96% and ICG: 60.57%), and drug loading content (DOX: 0.95% and ICG: 3.03%). Next, excellent NIR-I fluorescence and low toxicity of the BSA@ICG-DOX NPs were verified. Targeted NIR-I fluorescence images were obtained after intravenous injection of the NPs into the subcutaneous cervical tumors of the mice.

Conclusion

To improve the anti-tumor efficiency of the ICG@BSA NPs, the chemotherapeutic drug DOX was loaded into the BSA@ICG NPs. The NIR excitation/emission and targeted BSA@ICG-DOX NPs enables high-performance diagnosis and chemo/photothermal therapy of subcutaneous cervical tumors, providing a promising approach for further biomedical applications.

Polymer encapsulated clinical ICG nanoparticles for enhanced photothermal therapy and NIR fluorescence imaging in cervical cancer

Photothermal therapy (PTT) is a popular tumor therapy method, which is based on efficient photothermal nanoagents (PTNs). Clinical Indocyanine Green (ICG), as a Food and Drug Administration (FDA) approved agent, is an often-used PTN, meanwhile it is also a good near-infrared (NIR) fluorescence contrast agent. However, the further applications of ICG in biomedical fields are limited due to its poor stability. In this study, ICG was encapsulated by the amphiphilic polymer poly(styrene-co-maleic anhydride) (PSMA) to form ICG@PSMA nanoparticles. Furthermore, optical and thermal characteristics of ICG@PSMA nanoparticles were studied in detail. Strong NIR fluorescence and excellent photothermal properties of ICG@PSMA nanoparticles under 808 nm laser irradiation were measured. Besides, favorable biocompatibility of ICG@PSMA nanoparticles was demonstrated on a human cervical cancer cell line (HeLa) via cell viability studies. Hence, ICG@PSMA nanoparticles were further applied to enhanced PTT of living HeLa cells under 808 nm excitation, and a high PTT efficiency of ∼70% was obtained. The novel ICG nanoparticles as a promising PTT nanoplatform could offer an opportunity for further tumour treatments.

PSMA encapsulated Clinical ICG to form ICG@PSMA nanoparticles. ICG@PSMA nanoparticles showed strong NIR fluorescence and excellent photothermal properties.