Multimodal image-guided photothermal therapy mediated by 188Re-labeled micelles containing a cyanine-type photosensitizer

Engineering Diselenide-IR780 Homodimeric Nanoassemblies with Enhanced Photodynamic and Immunotherapeutic Effects for Triple-Negative Breast Cancer Treatment

Photodynamic therapy (PDT) has emerged as an efficient approach for non-invasive cancer treatment. However, organic small-molecule photosensitizers are often associated with defects in hydrophobicity, poor photostability, and aggregation-caused quenching, which limit their application. Usually, the carrier-assisted drug delivery system is a common strategy to solve the above obstacles, but additional carrier material could increase the risk of potential biological toxicity. The carrier-free drug delivery system with easy preparation and high drug-loading capability is proposed subsequently as a potential strategy to develop the clinical use of hydrophobic drugs. Herein, we rationally designed three IR780-based carrier-free nanosystems formed by carbon/disulfide/diselenide bond conjugated IR780-based homodimers. The IR780-based homodimers could self-assemble to form nanoparticles (DC-NP, DS-NP, DSe-NP) and exhibited higher reactive oxygen species generation capability and photostability than free IR780, in which DSe-NP with 808 nm laser irradiation performed best and resulted in the strongest cytotoxicity to 4T1 cells. Meanwhile, the glutathione consumption ability of DSe-NP boosted its PDT effect and then induced excessive oxidative stress of 4T1 cells, increasing antitumor efficacy by enhancing immunogenic cell death further. In tumor-bearing mice, DSe-NP displayed obvious tumor site accumulation, which obviously inhibited tumor growth and metastasis, and enhanced the immunological effect by effectively inducing dendritic cells to mature and activating T lymphocytes and natural killer cells. In summary, our study presented an IR780-based carrier-free nanodelivery system for a combination of PDT and immunity therapy and established expanding the application of organic small-molecule photosensitizers by an approach of carrier-free drug delivery system.

Macrocyclic-Albumin Conjugates for Precise Delivery of Radionuclides and Anticancer Drugs to Tumors

Precise delivery of radionuclides and anticancer drugs to tumor tissue is crucial to ensuring drug synergism and optimal therapeutic effects in radionuclide-based combination radio-chemotherapy. However, current codelivery vectors often rely on physical embedment/adsorption to load anticancer drugs, which lacks precise mechanisms for drug loading and release, resulting in unpredictable combination effects. Herein, a macrocyclic-albumin conjugate (MAC) that enables precise loading and controlled release of anticancer drugs is presented. By conjugating multiple macrocyclic hosts (sulfonate azocalix[4]arenes, SAC4A) to albumin molecules, the MAC facilitates the precise loading of anticancer drugs through host-guest interactions and site-specific labeling of radionuclides. Furthermore, the MAC degrades under hypoxic conditions, enabling the release of loaded drugs upon reaching tumor tissues. Through precise loading and targeted delivery of radionuclides and anticancer drugs, MAC achieves efficient cancer diagnosis and combined radio-chemotherapy in breast cancer cell (4T1)-bearing mice. Considering that SAC4A can load many anticancer drugs, MAC may provide a promising platform for effective combination radio-chemotherapy.

An Activatable Near-Infrared Fluorescent Probe for Precise Detection of the Pulmonary Metastatic Tumors: A Traditional Molecule Having a Stunning Turn

An accurate detection of lung metastasis is of great significance for making better treatment choices and improving cancer prognosis, but remains a big challenge in clinical practice. In this study, we propose a reinventing strategy to develop a pH-activatable near-infrared (NIR) fluorescent nanoprobe, pulmonary metastasis tracer (denoted as PMT), based on assembly of NIR dye IR780 and calcium phosphate (CaP). By delicately tuning the intermolecular interactions during the assembly process and dye doping content, as well as the synthetic condition of probe, the fluorescence of PMT could be finely adjusted via the tumor acidity-triggered disassembly. Notably, the selected PMT9 could sharply convert subtle pH variations into a distinct fluorescence signal to generate high fluorescence ON/OFF contrast, dramatically reducing the background signals. Benefiting from such preferable features, PMT9 is able to precisely identify not only the tumor sites in orthotopic lung cancer models but also the pulmonary metastases in mice with remarkable signal-to-background ratio (SBR). This study provides a unique strategy to turn shortcomings of traditional dye IR780 during in vivo imaging into advantages and further expand the application of fluorescent probe to image lung associated tumor lesions.

Investigating Effects of IR-780 in Animal Models of B16-F10 Melanoma: New Approach in Lung Metastasis

IR-780 is a fluorescent marker, photostable and non-toxic, and is widely used in tumor targeting; however, studies on the impact of IR-780 in animal models of B16-F10 melanoma are scarce in the literature. Therefore, this study aims to analyze behavior of this marker in melanoma cells using in vitro and in vivo analyses with fluorescence microscopy to conduct an analysis of cell culture, and an in vivo imaging system for an analysis of cell culture, tumor targeting on animals, and organ examination. In vitro analysis showed that B16-F10 cells at a concentration of 2 × 105 cells.plate-1 allowed a better visualization using 20 μM of IR-780. Furthermore, the location of IR-780 accumulation was confirmed by its fluorescence microscopy. Through in vivo studies, fluorescence was not observed in subcutaneous nodules, and it was found that animals that received intraperitoneal injection of B16-F10 cells presented ascites and did not absorb IR-780. Additionally, animals exhibiting lung metastasis showed fluorescence in ex vivo lung images. Therefore, use of the IR-780 marker for evaluating the progression of tumor growth did not demonstrate efficiency; however, it was effective in diagnosing pulmonary metastatic tumors. Although this marker presented limitations, results of evaluating pulmonary involvement through ex vivo fluorescence imaging were determined based on intensity of fluorescence.

Recent advances in fluorescence imaging-guided photothermal therapy and photodynamic therapy for cancer: From near-infrared-I to near-infrared-II

Phototherapy (including photothermal therapy, PTT; and photodynamic therapy, PDT) has been widely used for cancer treatment, but conventional PTT/PDT show limited therapeutic effects due to the lack of disease recognition ability. The integration of fluorescence imaging with PTT/PDT can reveal tumor locations in a real-time manner, holding great potential in early diagnosis and precision treatment of cancers. However, the traditional fluorescence imaging in the visible and near-infrared-I regions (VIS/NIR-I, 400-900 nm) might be interfered by the scattering and autofluorescence from tissues, leading to a low imaging resolution and high false positive rate. The deeper near-infrared-II (NIR-II, 1000-1700 nm) fluorescence imaging can address these interferences. Combining NIR-II fluorescence imaging with PTT/PDT can significantly improve the accuracy of tumor theranostics and minimize damages to normal tissues. This review summarized recent advances in tumor PTT/PDT and NIR-II fluorophores, especially discussed achievements, challenges and prospects around NIR-II fluorescence imaging-guided PTT/PDT for cancers.

Biodegradable nanomaterials for diagnosis and therapy of tumors

Although degradable nanomaterials have been widely designed and applied for cancer bioimaging and various cancer treatments, few reviews of biodegradable nanomaterials have been reported. Herein, we have summarized the representative research advances of biodegradable nanomaterials with respect to the mechanism of degradation and their application in tumor imaging and therapy. First, four kinds of tumor microenvironment (TME) responsive degradation are presented, including pH, glutathione (GSH), hypoxia and matrix metalloproteinase (MMP) responsive degradation. Second, external stimulation degradation is summarized briefly. Next, we have outlined the applications of nanomaterials in bioimaging. Finally, we have focused on some typical examples of biodegradable nanomaterials in radiotherapy (RT), photothermal therapy (PTT), starvation therapy, photodynamic therapy (PDT), chemotherapy, chemodynamic therapy (CDT), sonodynamic therapy (SDT), gene therapy, immunotherapy and combination therapy.

Synthesis and Self-Aggregation of Chlorophyll-a Derivatives Possessing a Hydroxymethyl Group in the C20-Substituent with Ethynylene and/or Phenylene Linkers

Chlorophyll(Chl)-a derivatives containing some rigid linkers in the C20 substituents, which were inserted between a hydroxymethyl group and the chlorin π-skeleton, were synthesized and their self-aggregation abilities were investigated. Measurements of electronic absorption, circular dichroism and infrared absorption spectra revealed that the zinc complex of a Chl-a derivative bearing a (p-ethynyl)benzyl alcoholic moiety at the C20-position gave its J-aggregates in an aqueous micellar solution through the hydrogen and coordination bonding. These results exhibited the potential of Chl-a derivatives bearing a hydroxyl group in the C20 substituents as the model compounds for chlorosomal light-harvesting antennas.

Systematic Screening and Therapeutic Evaluation of Glyconanoparticles with Differential Cancer Affinities for Targeted Cancer Therapy

Cancer-targeting ligands used for nanomedicines have been limited mostly to antibodies, peptides, aptamers, and small molecules thus far. Here, a library of glycocalyx-mimicking nanoparticles as a platform to enable screening and identification of cancer-targeting nanomedicines is reported. Specifically, a library of 31 artificial glycopolymers composed of either homogeneous or heterogeneous display of five different sugar moieties (β-glucose, β-galactose, α-mannose, β-N-acetyl glucosamine, and β-N-acetyl galactosamine) is converted to a library of glyconanoparticles (GlyNPs). GlyNPs optimal for targeting CT26, DU145, A549, and PC3 tumors are systematically screened and identified. The cypate-conjugated GlyNP displaying α-mannose and β-N-acetyl glucosamine show selective targeting and potent photothermal therapeutic efficacy against A549 human lung tumors. The docetaxel-contained GlyNP displaying β-glucose, β-galactose, and α-mannose demonstrate targeted chemotherapy against DU145 human prostate tumors. The results presented herein collectively demonstrate that the GlyNP library is a versatile platform enabling the identification of cancer-targeting glyconanoparticles and suggest its potential applicability for targeting various diseased cells beyond cancer.

MXenes: state-of-the-art synthesis, composites and bioapplications

MXenes have proven significant potential in a multitude of scientific domains as they provide substantial benefits over carbon graphene, such as ease of production and functionalization, large surface area, adjustable...

Multifunctional Mitochondria-Targeting Nanosystems for Enhanced Anticancer Efficacy

Mitochondria, a kind of subcellular organelle, play crucial roles in cancer cells as an energy source and as a generator of reactive substrates, which concern the generation, proliferation, drug resistance, and other functions of cancer. Therefore, precise delivery of anticancer agents to mitochondria can be a novel strategy for enhanced cancer treatment. Mitochondria have a four-layer structure with a high negative potential, which thereby prevents many molecules from reaching the mitochondria. Luckily, the advances in nanosystems have provided enormous hope to overcome this challenge. These nanosystems include liposomes, nanoparticles, and nanomicelles. Here, we summarize the very latest developments in mitochondria-targeting nanomedicines in cancer treatment as well as focus on designing multifunctional mitochondria-targeting nanosystems based on the latest nanotechnology.

Thermal-sensitive lipid nanoparticles potentiate anti-PD therapy through enhancing drug penetration and T lymphocytes infiltration in metastatic tumor

The response rate of anti-PD therapy in most cancer patients remains low. Therapeutic drug and tumor-infiltrating lymphocytes (TILs) are usually obstructed by the stromal region within tumor microenvironment (TME) rather than distributed around tumor cells, thus unable to induce the immune response of cytotoxic T cells. Here, we constructed the cationic thermosensitive lipid nanoparticles IR780/DPPC/BMS by introducing cationic NIR photosensitizer IR-780 iodide (IR780) modified lipid components, thermosensitive lipid DPPC and PD-1/PD-L1 inhibitor BMS202 (BMS). Upon laser irradiation, IR780/DPPC/BMS penetrated into deep tumor, and reduced cancer-associated fibroblasts (CAFs) around tumor cells to remodel the spatial distribution of TILs in TME. Interestingly, the cationic IR780/DPPC/BMS could capture released tumor-associated antigens (TAAs), thereby enhancing the antigen-presenting ability of DCs to activate cytotoxic T lymphocytes. Moreover, IR780/DPPC/BMS initiated gel-liquid crystal phase transition under laser irradiation, accelerating the disintegration of lipid bilayer structure and leading to the responsive release of BMS, which would reverse the tumor immunosuppression state by blocking PD-1/PD-L1 pathway for a long term. This combination treatment can synergistically exert the antitumor immune response and inhibit the tumor growth and metastasis.

Multifunctional Cyanine-Based Theranostic Probe for Cancer Imaging and Therapy

Cancer is one of the leading causes of death in the world. A cancer-targeted multifunctional probe labeled with the radionuclide has been developed to provide multi-modalities for NIR fluorescence and nuclear imaging (PET, SPECT), for photothermal therapy (PTT), and targeted radionuclide therapy of cancer. In this study, synthesis, characterization, in vitro, and in vivo biological evaluation of the cyanine-based probe (DOTA-NIR790) were demonstrated. The use of cyanine dyes for the selective accumulation of cancer cells were used to achieve the characteristics of tumor markers. Therefore, all kinds of organ tumors can be targeted for diagnosis and treatment. The DOTA-NIR790 labeled with lutetium-111 could detect original or metastatic tumors by using SPECT imaging and quantify tumor accumulation. The β-emission of ¹⁷⁷Lu-DOTA-NIR790 can be used for targeted radionuclide therapy of tumors. The DOTA-NIR790 enabled imaging by NIR fluorescence and by nuclear imaging (SPECT) to monitor in real-time the tumor accumulation and the situation of cancer therapy, and to guide the surgery or the photothermal therapy of the tumor. The radionuclide-labeled heptamethine cyanine based probe (DOTA-NIR790) offers multifunctional modalities for imaging and therapies of cancer.

A multifunctional targeted nanoprobe with high NIR-II PAI/MRI performance for precise theranostics of orthotopic early-stage hepatocellular carcinoma

Early diagnosis and effective treatment of hepatocellular carcinoma (HCC) is quite critical for improving patients' prognosis. The combination of second near-infrared window photoacoustic imaging (NIR-II PAI) and T₂-magnetic resonance imaging (T₂-MRI) is promising for achieving omnibearing information on HCC diagnosis due to the complementary advantages of outstanding optical contrast, high temporospatial resolution and soft-tissue resolution. Thus, the rational design of a multifunctional targeted nanoplatform with outstanding performance in dual-modal NIR-II PAI/T₂-MRI is particularly valuable for precise diagnosis and imaging-guided non-invasive photothermal therapy (PTT) of early-stage HCC. Herein, a versatile targeted organic-inorganic hybrid nanoprobe was synthesized as a HCC-specific contrast agent for sensitive and efficient theranostics. The developed multifunctional targeted nanoprobe yielded superior HCC specificity, reliable stability and biocompatibility, high imaging contrast in both NIR-II PAI and T₂-MRI, and an excellent photothermal conversion efficiency (74.6%). Furthermore, the theranostic efficiency of the targeted nanoprobe was systematically investigated using the orthotopic early HCC-bearing mice model. The NIR-II PAI exhibited sensitive detection of ultra-small HCCs (diameter less than 1.8 mm) and long-term real-time monitoring of the tumor and nanoprobe targeting process in deep tissues. The T₂-MRI demonstrated clear imaging contrast and a spatial relationship between micro-HCC and adjacent structures for a comprehensive description of the tumor. Moreover, when using the targeted nanoprobe, the non-invasively targeted PTT of orthotopic early HCC was carried out under reliable dual-modal imaging guidance with remarkable anti-tumor efficiency and biosafety. This study provides an insight for constructing a multifunctional targeted nanoplatform for precise and comprehensive theranostics of early-stage HCC, which would greatly benefit the patients in the era of precision medicine.

Mito-Bomb: Targeting Mitochondria for Cancer Therapy

Cancer has been one of the most common life-threatening diseases for a long time. Traditional cancer therapies such as surgery, chemotherapy (CT), and radiotherapy (RT) have limited effects due to drug resistance, unsatisfactory treatment efficiency, and side effects. In recent years, photodynamic therapy (PDT), photothermal therapy (PTT), and chemodynamic therapy (CDT) have been utilized for cancer treatment owing to their high selectivity, minor resistance, and minimal toxicity. Accumulating evidence has demonstrated that selective delivery of drugs to specific subcellular organelles can significantly enhance the efficiency of cancer therapy. Mitochondria-targeting therapeutic strategies are promising for cancer therapy, which is attributed to the essential role of mitochondria in the regulation of cancer cell apoptosis, metabolism, and more vulnerable to hyperthermia and oxidative damage. Herein, the rational design, functionalization, and applications of diverse mitochondria-targeting units, involving organic phosphine/sulfur salts, quaternary ammonium (QA) salts, peptides, transition-metal complexes, guanidinium or bisguanidinium, as well as mitochondria-targeting cancer therapies including PDT, PTT, CDT, and others are summarized. This review aims to furnish researchers with deep insights and hints in the design and applications of novel mitochondria-targeting agents for cancer therapy.

Development and application of ultrasound contrast agents in biomedicine

With the rapid development of molecular imaging, ultrasound (US) medicine has evolved from traditional imaging diagnosis to integrated diagnosis and treatment at the molecular level. Ultrasound contrast agents (UCAs) play a crucial role in the integration of US diagnosis and treatment. As the micro-bubbles (MBs) in UCAs can enhance the cavitation effect and promote the biological effect of US, UCAs have also been studied in the fields of US thrombolysis, mediated gene transfer, drug delivery, and high intensity focused US. The application range of UCAs is expanding, and the value of their applications is improving. This paper reviews the development and application of UCAs in biomedicine in recent years, and the existing problems and prospects are pointed out.

Recent Advances in Photosensitizers as Multifunctional Theranostic Agents for Imaging-Guided Photodynamic Therapy of Cancer

In recent years tremendous effort has been invested in the field of cancer diagnosis and treatment with an overall goal of improving cancer management, therapeutic outcome, patient survival, and quality of life. Photodynamic Therapy (PDT), which works on the principle of light-induced activation of photosensitizers (PS) leading to Reactive Oxygen Species (ROS) mediated cancer cell killing has received increased attention as a promising alternative to overcome several limitations of conventional cancer therapies. Compared to conventional therapies, PDT offers the advantages of selectivity, minimal invasiveness, localized treatment, and spatio-temporal control which minimizes the overall therapeutic side effects and can be repeated as needed without interfering with other treatments and inducing treatment resistance. Overall PDT efficacy requires proper planning of various parameters like localization and concentration of PS at the tumor site, light dose, oxygen concentration and heterogeneity of the tumor microenvironment, which can be achieved with advanced imaging techniques. Consequently, there has been tremendous interest in the rationale design of PS formulations to exploit their theranostic potential to unleash the imperative contribution of medical imaging in the context of successful PDT outcomes. Further, recent advances in PS formulations as activatable phototheranostic agents have shown promising potential for finely controlled imaging-guided PDT due to their propensity to specifically turning on diagnostic signals simultaneously with photodynamic effects in response to the tumor-specific stimuli. In this review, we have summarized the recent progress in the development of PS-based multifunctional theranostic agents for biomedical applications in multimodal imaging combined with PDT. We also present the role of different imaging modalities; magnetic resonance, optical, nuclear, acoustic, and photoacoustic in improving the pre-and post-PDT effects. We anticipate that the information presented in this review will encourage future development and design of PSs for improved image-guided PDT for cancer treatment.

Liposomal IR-780 as a Highly Stable Nanotheranostic Agent for Improved Photothermal/Photodynamic Therapy of Brain Tumors by Convection-Enhanced Delivery

Simple Summary

To improve the use of hydrophobic photosensitizer IR-780 in photothermal/photodynamic therapy (PTT/PDT), we entrap IR-780 within the lipid bilayer of liposomes (ILs). Compared to free IR-780, ILs showed well-preserved photothermal response by maintaining the photostability of IR-780 from repeated near infrared (NIR) laser exposure both in vitro and in vivo. Combined with fast endocytosis by human glioblastoma cells, ILs demonstrated enhanced cytotoxicity and induced higher cell apoptosis rate toward human glioblastoma cells over free IR-780, due to PTT with overexpression of heat shock protein and PDT with generation of intracellular reactive oxygen species. To overcome the blood–brain barrier, we used convection enhanced delivery (CED) for specific delivery of ILs to brain tumors in intracranial glioma xenograft. Upon three successive NIR laser irradiations, the liposomal IR-780 could significantly improve the anti-cancer efficacy in glioma treatment, leading to diminished intracranial tumor size and prolonged animal survival time.

Abstract

As a hydrophobic photosensitizer, IR-780 suffers from poor water solubility and low photostability under near infrared (NIR) light, which severely limits its use during successive NIR laser-assisted photothermal/photodynamic therapy (PTT/PDT). To solve this problem, we fabricate cationic IR-780-loaded liposomes (ILs) by entrapping IR-780 within the lipid bilayer of liposomes. We demonstrate enhanced photostability of IR-780 in ILs with well-preserved photothermal response after three repeated NIR laser exposures, in contrast to the rapid decomposition of free IR-780. The cationic nature of ILs promotes fast endocytosis of liposomal IR-780 by U87MG human glioblastoma cells within 30 min. For PTT/PDT in vitro, ILs treatment plus NIR laser irradiation leads to overexpression of heat shock protein 70 and generation of intracellular reactive oxygen species by U87MG cells, resulting in enhanced cytotoxicity and higher cell apoptosis rate. Using intracranial glioma xenograft in nude mice and administration of ILs by convection enhanced delivery (CED) to overcome blood-brain barrier, liposomal IR-780 could be specifically delivered to the brain tumor, as demonstrated from fluorescence imaging. By providing a highly stable liposomal IR-780, ILs significantly improved anti-cancer efficacy in glioma treatment, as revealed from various diagnostic imaging tools and histological examination. Overall, CED of ILs plus successive laser-assisted PTT/PDT may be an alternative approach for treating brain tumor, which can retard glioma growth and prolong animal survival times from orthotopic brain tumor models.

Folate-targeted Pluronic-chitosan nanocapsules loaded with IR780 for near-infrared fluorescence imaging and photothermal-photodynamic therapy of ovarian cancer

Herein, we report the fabrication of a nanotherapeutic platform integrating near-infrared (NIR) imaging with combined therapeutic potential through photodynamic (PDT) and photothermal therapies (PTT) and recognition functionality against ovarian cancer. Owing to its NIR fluorescence, singlet oxygen generation and heating capacity, IR780 iodide is exploited to construct a multifunctional nanosystem for single-wavelength NIR laser imaging-assisted dual-modal phototherapy. We opted for loading IR780 into polymeric Pluronic-F127-chitosan nanoformulation in order to overcome its hydrophobicity and toxicity and to allow functionalization with folic acid. The obtained nanocapsules show temperature-dependent swelling and spectroscopic behavior with favorable size distribution for cellular uptake at physiological temperatures, improved fluorescence properties and good stability. The fabricated nanocapsules can efficiently generate singlet oxygen in solution and are able to produce considerable temperature increase (46 °C) upon NIR laser irradiation. Viability assays on NIH-OVCAR-3 cells confirm the successful biocompatibilization of IR780 by encapsulating in Pluronic and chitosan polymers. NIR fluorescence imaging assays reveal the ability of folic-acid functionalized nanocapsules to serve as intracellular contrast agents and demonstrate their active targeting capacity against folate receptor expressing ovarian cancer cells (NIH-OVCAR-3). Consequently, the targeted nanocapsules show improved NIR laser induced phototherapeutic performance against NIH-OVCAR-3 cells compared to free IR780. We anticipate that this class of nanocapsules holds great promise as theranostic agents for application in image-guided dual PDT-PTT and imaging assisted surgery of ovarian cancer.

Self-promoted Albumin-Based Nanoparticles for Combination Therapy against Metastatic Breast Cancer via a Hyperthermia-Induced "Platelet Bridge"

It has been a great challenge to simultaneously inhibit the outgrowth of both the primary tumor and metastasis in metastatic cancer treatment. Substantial studies have evidenced that the interaction of platelets and cancer cells supports tumor metastasis, and platelets are considered to have metastasis-targeting property. Inspired by injury-targeting and metastasis-targeting properties of platelets, we constructed a photothermal therapy strategy with activated platelet-targeting albumin-based nanoparticles, PSN-HSA-PTX-IR780, to amplify drug delivery in the primary tumor at mild temperatures and simultaneously inhibit metastasis via a "platelet bridge". Human serum albumin (HSA) was premodified with a P-selectin-targeting peptide (PSN peptide) or IR780 serving as a photosensitizer. Hybrid albumin nanoparticles were assembled via the disulfide reprogramming method and encapsulated paclitaxel (PTX) to formulate PSN-HSA-PTX-IR780. The PSN-modified albumin nanoparticles could bind with upregulated P-selectin on activated platelets and subsequently target cancer cells by using platelets as a "bridge". In addition, nanoparticle-generated hyperthermia induced tissue injury and increased tumor-infiltrating platelets, thereby recruiting more nanoparticles into the tumor in a self-promoted way. In vivo studies showed that the drug accumulation of PSN-HSA-PTX-IR780 was 2.86-fold higher than that of HSA-PTX-IR780 at the optimal temperature (45 °C), which consequently improved the therapeutic outcome. Moreover, PSN-HSA-PTX-IR780 also effectively targets and inhibits lung metastasis by binding with metastasis-infiltrating platelets. Altogether, the self-promoted nanoplatform provides a unique and promising strategy for metastatic cancer treatment with enhanced drug delivery efficacy.

Sequence-Defined Nanotubes Assembled from IR780-Conjugated Peptoids for Chemophototherapy of Malignant Glioma

Near-infrared (NIR) laser-induced phototherapy through NIR agents has demonstrated the great potential for cancer therapy. However, insufficient tumor killing due to the nonuniform heat or cytotoxic singlet oxygen (1O2) distribution over tumors from phototherapy results in tumor recurrence and inferior outcomes. To achieve high tumor killing efficacy, one of the solutions is to employ the combinational treatment of phototherapy with other modalities, especially with chemotherapeutic agents. In this paper, a simple and effective multimodal therapeutic system was designed via combining chemotherapy, photothermal therapy (PTT), and photodynamic therapy (PDT) to achieve the polytherapy of malignant glioma which is one of the most aggressive tumors in the brain. IR-780 (IR780) dye-labeled tube-forming peptoids (PepIR) were synthesized and self-assembled into crystalline nanotubes (PepIR nanotubes). These PepIR nanotubes showed an excellent efficacy for PDT/PTT because the IR780 photosensitizers were effectively packed and separated from each other within crystalline nanotubes by tuning IR780 density; thus, a self-quenching of these IR780 molecules was significantly reduced. Moreover, the efficient DOX loading achieved due to the nanotube large surface area contributed to an efficient and synergistic chemotherapy against glioma cells. Given the unique properties of peptoids and peptoid nanotubes, we believe that the developed multimodal DOX-loaded PepIR nanotubes in this work offer great promises for future glioma therapy in clinic.

Activation Strategies in Image-Guided Nanotherapeutic Delivery

Therapeutic nanomaterials serve as an important platform for drug delivery under image guidance. Despite significant growth and broad applications, their design specifics remain a subject of continued interest primarily due to multifunctional factors involved, ranging from nanomaterial properties, imaging modalities, and therapeutic agents to activation strategies. This review article summarizes key findings on their design characteristics with a particular interest in strategies developed for therapeutic activation (release). First, their activation can be controlled using either an endogenous factor including low pH and glutathione or an external stimulation by light, ultrasound, or electromagnetic field. The former is passively controlled from a spatiotemporal aspect compared to the latter, which is otherwise actively controlled through drug linker photolysis, nanomaterial disassembly, or gate opening. Second, light stimulation serves a most notable strategy due to its essential role in controlled drug release, photothermal activation (hyperthermia), and photodynamic production of reactive oxygen species (ROS). Third, some of those activation strategies that rely on ultrasound, photothermal, photoacoustic, magnetic field, or X-ray radiation are dually functional due to their role in imaging modalities. In summary, this review article presents recent advances and new insights that pertain to nanotherapeutic delivery systems. It also addresses their technical limitations associated with tissue penetration (light), spatial resolution (ultrasound, hyperthermia), and occurrence of cellular resistance (ROS).

Quantitative measurements of IR780 in formulations and tissues

PURPOSE

IR780 iodide, a promising near-infrared dye, is widely used to prepare nanoparticles as a theranostic agent for tumor imaging and therapy. However, there are no validated (bio)analytical methods to measure IR780 in nanoparticles and tissues in literature. The aim of this study is to develop and validate a new HPLC method to measure IR780 concentration in IR780 formulations as well as a new LC-MS/MS method to measure IR780 concentration in tissue samples, particularly in liver and lung.

MATERIALS AND METHODS

IR780 granules that produced IR780 in situ self-assembled nanoparticles upon contact with water were prepared at two drug loadings (0.2 % and 0.37 %). An HPLC method was developed and validated to measure IR780 concentrations in IR780 granules and nanoparticles. Furthermore, a validated LC-MS/MS method was developed to measure IR780 in mouse liver and lung. Both HPLC method and LC-MS/MS method were validated in terms of specificity, stability, linearity, limit of detection, limit of quantification, accuracy and precision.

RESULTS

Both HPLC method and LC-MS/MS method achieved the criteria for method validation. The HPLC method was accurate in the concentration range of 0.5-25 μg/mL. The measured drug loadings were 95 % of the theoretical drug loadings. The validated LC-MS/MS method can quantitatively measure the concentrations of IR780 in liver and lung. The linear range of the LC-MS/MS method was 1-1000 ng/mL for both liver and lung samples. IR780 granules showed the lung selectivity compared to IR780 solution at 2 h after oral administration.

CONCLUSION

A validated HPLC method was developed to measure IR780 concentration in pharmaceutical formulations and a validated LC-MS/MS method was developed to measure IR780 concentration in tissues. These quantitative methods provide reliable measurements of IR780 in pharmaceutic formulations and biological samples, which will significantly facilitate the research of IR780 as a theranostic agent for cancer therapy and imaging.

Conjugated Photosensitizers for Imaging and PDT in Cancer Research

Early cancer detection and perfect understanding of the disease are imperative toward efficient treatments. It is straightforward that, for choosing a specific cancer treatment methodology, diagnostic agents undertake a critical role. Imaging is an extremely intriguing tool since it assumes a follow up to treatments to survey the accomplishment of the treatment and to recognize any conceivable repeating injuries. It also permits analysis of the disease, as well as to pursue treatment and monitor the possible changes that happen on the tumor. Likewise, it allows screening the adequacy of treatment and visualizing the state of the tumor. Additionally, when the treatment is finished, observing the patient is imperative to evaluate the treatment methodology and adjust the treatment if necessary. The goal of this review is to present an overview of conjugated photosensitizers for imaging and therapy.

Suppression of cancer proliferation and metastasis by a versatile nanomedicine integrating photodynamic therapy, photothermal therapy, and enzyme inhibition

Cancer therapeutics are varied and target diverse processes in cancer progression. Photodynamic therapy (PDT), photothermal therapy (PTT), and the inhibition of pro-cancer proteases are non-invasive anticancer therapeutics that attract increasing attentions for their enhanced specificities and milder systemic toxicities compared to traditional therapeutics. These modalities offer advantages to compensate for the shortcomings of their counterparts. For instance, PDT or PTT efficiently eliminates locally confined tumor cells while exhibiting no effect on metastatic tumor cells. In contrast, the inhibition of pro-cancer proteases systemically suppresses the proliferation and metastasis of cancer cells but does not eradicate existing cancer cells. To synergize these therapeutics, we hereby report a versatile nanoparticle that integrates the effects of PDT, PTT, and enzyme-inhibition. This nanoparticle (CIKP-NP) was synthesized by covalently or non-covalently modifying a photothermal nanoparticle with a photosensitizer, a pro-cancer protease inhibitor, and an albumin-binding molecule. After confirming the PDT, PTT, albumin-binding, and enzyme-inhibition properties at the molecular level, we demonstrated that CIKP-NP killed tumor cells through PDT or PTT and suppressed tumor cell invasion through enzyme-inhibition. In addition, through a breast cancer xenograft mouse model, we demonstrated that CIKP-NP suppressed tumor growth by PDT or PTT effect. Notably, the synergism of PDT and PTT significantly enhanced its anticancer efficiency. Furthermore, CIKP-NP significantly suppressed cancer metastasis in a lung metastatic mouse model. Last, biodistribution and the in vivo retention of CIKP-NP confirmed the tumor-targeting property. Beyond demonstrating the anti-tumor and anti-metastatic efficacy of CIKP-NP, our study also suggests a new strategy to synergize multiple anticancer therapeutics.

Near-Infrared Activated Cyanine Dyes As Agents for Photothermal Therapy and Diagnosis of Tumors

Today, it has become apparent that innovative treatment methods, including those involving simultaneous diagnosis and therapy, are particularly in demand in modern cancer medicine. The development of nanomedicine offers new ways of increasing the therapeutic index and minimizing side effects. The development of photoactivatable dyes that are effectively absorbed in the first transparency window of biological tissues (700-900 nm) and are capable of fluorescence and heat generation has led to the emergence of phototheranostics, an approach that combines the bioimaging of deep tumors and metastases and their photothermal treatment. The creation of near-infrared (NIR) light-activated agents for sensitive fluorescence bioimaging and phototherapy is a priority in phototheranostics, because the excitation of drugs and/or diagnostic substances in the near-infrared region exhibits advantages such as deep penetration into tissues and a weak baseline level of autofluorescence. In this review, we focus on NIR-excited dyes and discuss prospects for their application in photothermal therapy and the diagnosis of cancer. Particular attention is focused on the consideration of new multifunctional nanoplatforms for phototheranostics which allow one to achieve a synergistic effect in combinatorial photothermal, photodynamic, and/or chemotherapy, with simultaneous fluorescence, acoustic, and/or magnetic resonance imaging.

In vivo near-infrared fluorescent optical imaging for CNS drug discovery

INTRODUCTION

In vivo imaging technologies have become integral and essential component of drug discovery, development, and clinical assessment for central nervous system (CNS) diseases. Near-infrared (NIR) fluorescence imaging in the range of 650-950 nm is widely used for pre-clinical in vivo imaging studies. The recent expansion of NIR imaging into the shortwave infrared (SWIR, 1000-1700 nm) window enabled improvements in tissue penetration and resolution required for anatomical, dynamic, and molecular neuroimaging with high potential for clinical translation.

AREAS COVERED

This review focuses on the latest progress in near-infrared (NIR)-fluorescent optical imaging modalities with an emphasis on the SWIR window. Advantages and challenges in developing novel organic and inorganic SWIR emitters, with special attention to their toxicology and pharmacology, are discussed. Examples of their application in preclinical imaging of brain function and pathology provide a platform to assess the potential for their clinical translation.

EXPERT OPINION

Propelled through concomitant technological advancements in imaging instrumentation, algorithms and new SWIR emitters, SWIR imaging has addressed key barriers to optical imaging modalities used in pre-clinical studies addressing the CNS. Development of biocompatible SWIR emitters and adoption of SWIR into multi-modal imaging modalities promise to rapidly advance optical imaging into translational studies and clinical applications.

AIEgens Conjugation Improves the Photothermal Efficacy and Near-Infrared Imaging of Heptamethine Cyanine IR-780

Near-infrared (NIR) fluorescent probes can deeply penetrate through tissues with little damage. To facilitate image-guided theranostics, researchers usually apply a desired amount of photosensitizers to achieve effective photothermal responses. However, these probes could easily suffer from low photostability and aggregated-caused quenching effect in high concentrations. In this paper, the rational incorporation of an aggregated-induced emission (AIE) unit into the structure of heptamethine cyanine IR-780 is reported. Using tetraphenylethene (TPE) as an AIE core, we synthesize three TPE-modified IR-780 probes (IR-780 AIEgens) via different linkages. The IR-780 derivatives all show enhanced AIE features, in which the probe with an ether linkage (IR780-O-TPE) is superior in rapid cell uptake, high targeting capacity, and good photostability. Moreover, IR780-O-TPE exhibits the strongest cytotoxicity to HeLa cells (IC₅₀ = 3.3 μM). The three IR-780 derivatives displayed a photothermal response in a concentration-dependent manner, in which IR-780 AIEgens are more cytotoxic than IR-780, with IC₅₀ of 0.3 μM under 808 nm laser irradiation. In tumor-bearing mice, the optimal probe IR780-O-TPE also showed a more effective photothermal response than IR-780. By illustrating the relationship between aggregation state with photophysical properties, cell imaging, and cytotoxicity, this work is helpful in modulating NIR-based photosensitizers into AIE features for efficient image-guided theranostics.

Mitochondria-targeted nanospheres with deep tumor penetration for photo/starvation therapy

IR780 and GOx based PLGA nanospheres can not only selectively accumulate in mitochondria but penetrate into 3D tumors deeply, achieving synergistic treatment of phototherapy and GOx-induced starvation therapy under dual-imaging guidance/monitoring.

Facile synthesis of Au@Mn3O4 magneto-plasmonic nanoflowers for T1-weighted magnetic resonance imaging and photothermal therapy of cancer

The integration of advanced diagnostic contrast agents with versatile therapeutic nanoparticles presents an effective method for cancer treatment.

An NIR-responsive mesoporous silica nanosystem for synergetic photothermal-immunoenhancement therapy of hepatocellular carcinoma

To create a more precise, efficient imaging and therapeutic strategy is a big challenge for the current treatment of hepatocellular carcinoma (HCC). Photothermal therapy (PTT) has attracted enormous attention due to its non-invasive property and precise spatial and temporal control. Here, we developed a strategy to realize superior imaging performance and treatment, utilizing an indocyanine green (ICG) and sorafenib (S) co-loaded mesoporous silica nanosystem for synergetic PTT/immuno-enhanced therapy. We proved that (ICG+S)@mSiO₂ could be easily endocytosed by H22 cells, carried out outstanding real-time fluorescence imaging, and enhanced cytotoxicity abilities by near-infrared radiation (NIR) in vitro. Moreover, (ICG+S)@mSiO₂ also had excellent fluorescence imaging ability, displayed a remarkable photothermal tumor killing effect and immune enhancement capability under 808 nm irradiation in an H22 tumor-bearing mice model, without apparent adverse effects in other organs. This study provides a new strategy for the development of a PTT/immuno-enhanced synergistic theranostic nanosystem of HCC.

N-Doped Carbon Quantum Dot (NCQD)-Deposited Carbon Capsules for Synergistic Fluorescence Imaging and Photothermal Therapy of Oral Cancer

Use of nanomaterials blessed with both therapeutic and diagnostic properties is a proficient strategy in the treatment of cancer in its early stage. In this context, our paper reports the synthesis of uniform size N-rich mesoporous carbon nanospheres of size 65-70 nm from pyrrole and aniline precursors using Triton-X as a structure-directing agent. Transmission electron microscopy reveals that these carbons spheres contain void spaces in which ultrasmall nitrogen-doped quantum dots (NCQD) are captured within the matrix. These mesoporous hollow NCQD captured carbon spheres (NCQD-HCS) show fluorescence quantum yield up to 14.6% under λ_ex = 340 nm. Interestingly, samples calcined at >800 °C clearly absorb in the wavelength range 700-1000 nm and shows light-to-heat conversion efficiency up to 52%. In vitro experiments in human oral cancer cells (FaDu) show that NCQD-HCS are internalized by the cells and induce a substantial thermal ablation effect in FaDu cells when exposed under a 980 nm near-infrared laser.

Smart H2S-Triggered/Therapeutic System (SHTS)-Based Nanomedicine

Hydrogen sulfide (H2S) is of vital importance in several biological and physical processes. The significance of H2S-specific detection and monitoring is emphasized by its elevated levels in various diseases such as cancer. Nanotechnology enhances the performance of chemical sensing nanoprobes due to the enhanced efficiency and sensitivity. Recently, extensive research efforts have been dedicated to developing novel smart H2S-triggered/therapeutic system (SHTS) nanoplatforms for H2S-activated sensing, imaging, and therapy. Herein, the latest SHTS-based nanomaterials are summarized and discussed in detail. In addition, therapeutic strategies mediated by endogenous H2S as a trigger or exogenous H2S delivery are also included. A comprehensive understanding of the current status of SHTS-based strategies will greatly facilitate innovation in this field. Lastly, the challenges and key issues related to the design and development of SHTS-based nanomaterials (e.g., morphology, surface modification, therapeutic strategies, appropriate application, and selection of nanomaterials) are outlined.

Recent Advances in Nanomaterials-Based Chemo-Photothermal Combination Therapy for Improving Cancer Treatment

Conventional chemotherapy for cancer treatment is usually compromised by shortcomings such as insufficient therapeutic outcome and undesired side effects. The past decade has witnessed the rapid development of combination therapy by integrating chemotherapy with hyperthermia for enhanced therapeutic efficacy. Near-infrared (NIR) light-mediated photothermal therapy, which has advantages such as great capacity of heat ablation and minimally invasive manner, has emerged as a powerful approach for cancer treatment. A variety of nanomaterials absorbing NIR light to generate heat have been developed to simultaneously act as carriers for chemotherapeutic drugs, contributing as heat trigger for drug release and/or inducing hyperthermia for synergistic effects. This review aims to summarize the recent development of advanced nanomaterials in chemo-photothermal combination therapy, including metal-, carbon-based nanomaterials and particularly organic nanomaterials. The potential challenges and perspectives for the future development of nanomaterials-based chemo-photothermal therapy were also discussed.

Folate-Targeted and Oxygen/Indocyanine Green-Loaded Lipid Nanoparticles for Dual-Mode Imaging and Photo-sonodynamic/Photothermal Therapy of Ovarian Cancer in Vitro and in Vivo

We have successfully fabricated versatile folate-targeted and oxygen/indocyanine green-loaded lipid nanoparticles (FA-OINPs) for dual-mode imaging-guided therapy in ovarian cancer cells and subcutaneous xenograft models. FA-OINPs were demonstrated to have great potential as superb contrast agents to enhance ultrasound and photoacoustic (US/PA) imaging We have successfully fabricated versatile folate-targeted and oxygen/indocyanine green-loaded lipid nanoparticles (FA-OINPs) for dual-mode imaging-guided therapy in ovarian cancer cells and subcutaneous xenograft models. FA-OINPs were demonstrated to have great potential as superb contrast agents to enhance ultrasound and photoacoustic (US/PA) imaging in vitro and in vivo. Confocal laser scanning microscopy and flow cytometry analysis verified that FA-OINPs could specifically target SKOV3 ovarian cancer cells and be endocytosed with a remarkable efficiency. Compared with other therapeutic options, FA-OINPs exhibited an excellent therapeutic outcome after exposure to laser and ultrasound. The MTT assay and flow cytometry analysis confirmed that cytotoxicity effects and apoptosis/necrosis rates were significantly increased. The fluorescence microscopy and fluorescence microplate reader detection validated that the generation of intracellular reactive oxygen species (ROS) was dramatically improved. Immunohistochemical analyses of tumor tissues demonstrated the enhanced tumor apoptosis, the decreased vascular endothelial growth factor (VEGF) and microvascular density (MVD) expression, and the decreased expression of CD68 after treatment. The presented results suggest that photo-sonodynamic/photothermal mediated FA-OINPs could provide a promising strategy for synergistic therapy in ovarian cancer with the guidance of US/PA dual-mode imaging.

Theranostic Nanomedicine Carrying L-Menthol and Near-Infrared Dye for Multimodal Imaging-Guided Photothermal Therapy of Cancer

Photothermal therapy (PTT) as an emerging technique for cancer treatment has drawn great attention owing to its minimally invasive nature. However, it is difficult to achieve a complete tumor regression due to the heterogeneous heat distribution over the tumor. Application of photothermal conversion agents may enhance PTT efficiency, and a multifunctional imaging may provide guidance for the implementation of PTT. Herein, an L-menthol/IR-780 loaded liposome (MIL) is prepared to achieve NIR-triggered cavitation for enhancing photothermal ablation. The synthesized MIL possesses outstanding colloidal stability and photoacoustic/near infrared fluorescence/ultrasound (PA/NIRF/US) imaging contrast to offer multimodal imaging-guided photothermal therapy of cancer. Upon irradiation, the IR-780 acts as the photoabsorber to convert NIR light into heat energy. More importantly, the produced hyperthermia can not only induce ablation of tumor cells but also trigger vaporization and bubbling of encapsulated L-menthol (menthol). Consequently, the generated menthol bubbles obviously enhance the US imaging signal and promote photothermal ablation of the tumor.

Combinational phototherapy and hypoxia-activated chemotherapy favoring antitumor immune responses

Background: Tumor metastasis is responsible for most cancer death worldwide, which lacks curative treatment.

Purpose: The objective of this study was to eliminate tumor and control the development of tumor metastasis.

Methods: Herein, we demonstrated a smart nano-enabled platform, in which 2-[2-[2-chloro-3-[(1,3-dihydro-3,3-dimethyl-1-propyl-2h-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl]ethenyl]-3,3-dimethyl-1-propylindolium iodide (IR780) and tirapazamine (TPZ) were co-loaded in poly(ε-caprolactone)-poly(ethylene glycol) (PEG-PCL) to form versatile nanoparticles (PEG-PCL-IR780-TPZ NPs).

Results: The intelligence of the system was reflected in the triggered and controlled engineering. Specially, PEG-PCL not only prolonged the circulation time of IR780 and TPZ but also promoted tumor accumulation of nanodrugs through enhanced permeability and retention (EPR) effect. Moreover, reactive oxygen species (ROS) generated by IR780 armed by an 808 nm laser irradiation evoked a cargo release. Meanwhile, IR780, as a mitochondria-targeting phototherapy agent exacerbated tumor hypoxic microenvironment and activated TPZ for accomplishing hypoxia-activated chemotherapy. Most significantly, IR780 was capable of triggering immunogenic cell death (ICD) during the synergic treatment. ICD biomarkers as a “danger signal” accelerated dendritic cells (DCs) maturation, and subsequently activated toxic T lymphocytes.

Conclusion: Eventually, antitumor immune responses stimulated by combinational phototherapy and hypoxia-activated chemotherapy revolutionized the current landscape of cancer treatment, strikingly inhibiting tumor metastasis and providing a promising prospect in the clinical application.

IR780-based light-responsive nanocomplexes combining phase transition for enhancing multimodal imaging-guided photothermal therapy

Near-infrared (NIR) light-triggered photothermal therapy (PTT) has been widely applied for treating cancer. The combination of nanotechnology and NIR has shown great promise for promoting the efficacy of PTT. However, PTT alone could not completely ablate the tumors and easily causes tumor recurrence. To overcome this challenge, many studies have been performed to enhance PTT, including combining chemical therapy and radiotherapy, both of which have side effects on the body. To reduce the side effects and enhance PTT, a new infrared IR780-based nanocomplex combining liquid fluorocarbon perfluoropentane (PFP) has been synthesized for enhancing multimodal imaging-guided PTT. Under NIR irradiation, the size changes of PFP-loaded nanobubbles transforming into microbubbles allow ultrasound (US) imaging, showing boundaries and internal information of tumors. The breakup process and cascade reaction of phase transition can improve intratumoral permeation and retention of nanoparticles in nonmicrovascular tissue and damage the cell membranes of tumors, further enhancing PTT to kill tumor cells. The strong absorption in the NIR field of IR780-loaded NPs allows not only photoacoustic (PA) imaging but also NIR fluorescence (NIRF) imaging, which provides more anatomical information about tumors. This nanocomplex exhibits good biocompatibility and nontoxicity, strong PA/US/NIRF imaging contrast, excellent liquid-gas transition and a photothermal effect. This finding provides a new method to enhance multimodal imaging-guided cancer nanotheranostics.

Co-precipitation Synthesis of Near-infrared Iron Oxide Nanocrystals on Magnetically Targeted Imaging and Photothermal Cancer Therapy via Photoablative Protein Denature

Near-infrared (NIR)-based nanomaterials that provide efficient tumor ablation for cancer therapy have been reported. However, the issues of biocompatibility of metals or ions in inorganic nanoparticles systems such as copper and gold nanoparticles are still a matter of concern. In this study, we developed a facile and ligand-assisted co-precipitation method to synthesize biocompatible iron oxide (IO) nanocrystals with NIR absorption that provided T2-weighted magnetic resonance (MR) images and photothermal ablation characteristics suitable for cancer theranostics. Our results showed that 150-nm particles can be synthesized and optimized by using different amounts of ligand. NIR-IO nanocrystals of this size showed high photothermal conversion efficiency (21.2%) and T2-weighted MR contrast (transverse relaxivity value approximately 141 S-1 mM-1). The NIR-IO nanocrystals showed no cytotoxicity in HT-29 colorectal cancer cells without irradiation, whereas the viability of cells that received NIR-IO nanocrystals decreased significantly after 808-nm laser irradiation. The mechanism of cell death may involve alterations in protein secondary structure and membrane permeability. For in vivo studies, 4-fold enhanced tumor accumulation was significantly observed of NIR-IO nanocrystals with a magnetic field (MF) application, resulting in a 3-fold higher T2-weighted MR signal than that produced by a commercial T2-weighted MR contrast agent (Resovist®) and excellent photothermal efficacy (approximately 53 °C) for cancer treatment. The innovative NIR-IO nanocrystals showed excellent biocompatibility and have great potential as a theranostic agent against cancer.