Near-infrared light-responsive nanomaterials for cancer theranostics

Engineering Ag-Decorated Graphene Oxide Nano-Photothermal Platforms with Enhanced Antibacterial Properties for Promoting Infectious Wound Healing

Introduction

Graphene oxide (GO) nanoparticles have emerged as a compelling photothermal agent (PHTA) in the realm of photothermal antibacterial therapy, owing to their cost-effectiveness, facile synthesis, and remarkable photostability. Nevertheless, the therapeutic efficacy of GO nanoparticles is commonly hindered by their inherent drawback of low photothermal conversion efficiency (PCE).

Methods

Herein, we engineer the Ag/GO-GelMA platform by growing the Ag on the surface of GO and encapsulating the Ag/GO nanoparticles into the GelMA hydrogels.

Results

The resulting Ag/GO-GelMA platform demonstrates a significantly enhanced PCE (47.6%), surpassing that of pure GO (11.8%) by more than fourfold. As expected, the Ag/GO-GelMA platform, which was designed to integrate the benefits of Ag/GO nanoparticles (high PCE) and hydrogel (slowly releasing Ag+ to exert an inherent antibacterial effect), has been shown to exhibit exceptional antibacterial efficacy. Furthermore, transcriptome analyses demonstrated that the Ag/GO-GelMA platform could significantly down-regulate pathways linked to inflammation (the MAPK and PI3K-Akt pathways) and had the ability to promote cell migration.

Discussion

Taken together, this study presents the design of a potent photothermal antibacterial platform (Ag/GO-GelMA) aimed at enhancing the healing of infectious wounds. The platform utilizes a handy method to enhance the PCE of GO, thereby making notable progress in the utilization of GO nano-PHTAs.

Environmental stimulus-responsive mesoporous silica nanoparticles as anticancer drug delivery platforms

Currently, cancer poses a significant health challenge in the medical community. Traditional chemotherapeutic agents are often accompanied by toxic side effects and limited therapeutic efficacy, restricting their application and advancement in cancer treatment. Therefore, there is an urgent need for developing intelligent drug release systems. Mesoporous silica nanoparticles (MSNs) have many advantages, such as a large specific surface area, substantial pore volume and size, adjustable mesoporous material pore size, excellent biocompatibility, and thermodynamic stability, making them ideal carriers for drug delivery and release. Additionally, they have been widely used to develop novel anticancer drug carriers. Recently, MSNs have been employed to design responsive systems that react to the tumor microenvironment and external stimuli for controlled release of anticancer drugs. This includes factors within the intratumor environment, such as pH, temperature, enzymes, and glutathione as well as external tumor stimuli, such as light, magnetic field, and ultrasound, among others. In this review, we discuss the research progress on environmental stimulus-responsive MSNs in anticancer drug delivery systems, including internal and external environment single stimulus-responsive release and combined stimulus-responsive release. We also summarize the current challenges associated with environmental stimulus-responsive MSNs and elucidate future directions, providing a reference for the functionalization modification and practical application of these MSNs.

Near-infrared absorbing semiconducting polymer nanomedicines for cancer therapy

As a new type of organic optical nanomaterials, semiconducting polymer nanoparticles (SPNs) have the advantages of good optical characteristics and photostability, low toxicity concerns, and relatively simple preparation processes. Particularly, near-infrared (NIR) absorbing SPNs have shown a great promise in biomedicine. In addition to acting as nanoprobes for molecular imaging, these SPNs can produce local heat and reactive oxygen species with the stimulation of NIR light, allowing photothermal therapy (PTT) and photodynamic therapy (PDT), respectively. Herein, we summarize the recent development of SPN-based nanomedicines for cancer therapy. The rational designs of SPNs for enhanced PTT, PDT, or combinational PTT/PDT to achieve effective ablation of tumor tissues are highlighted. Via loading/conjugating SPNs with other therapeutic elements (such as chemotherapeutic drugs and immunotherapeutic agents), phototherapy-combined chemotherapy or immunotherapy can be realized, which is then discussed. In especial, the constructions of SPN-based nanomedicines for NIR photoactivatable chemotherapy and immunotherapy are introduced with representative examples. Finally, we discuss the current challenges and key concerns of SPNs for their biomedical applications and give an outlook for their future clinical translation. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Advances in photobiomodulation for cognitive improvement by near-infrared derived multiple strategies

Cognitive function is an important ability of the brain, but cognitive dysfunction can easily develop once the brain is injured in various neuropathological conditions or diseases. Photobiomodulation therapy is a type of noninvasive physical therapy that is gradually emerging in the field of neuroscience. Transcranial photobiomodulation has been commonly used to regulate neural activity in the superficial cortex. To stimulate deeper brain activity, advanced photobiomodulation techniques in conjunction with photosensitive nanoparticles have been developed. This review addresses the mechanisms of photobiomodulation on neurons and neural networks and discusses the advantages, disadvantages and potential applications of photobiomodulation alone or in combination with photosensitive nanoparticles. Photobiomodulation and its associated strategies may provide new breakthrough treatments for cognitive improvement.

Graphene-based nanomaterials for stimuli-sensitive controlled delivery of therapeutic molecules

Stimuli-responsive drug delivery has attracted tremendous attention in the past decades. It provides a spatial- and temporal-controlled release in response to different triggers, thus enabling highly efficient drug delivery and minimizing drug side effects. Graphene-based nanomaterials have been broadly explored, and they show great potential in smart drug delivery due to their stimuli-responsive behavior and high loading capacity for an extended range of drug molecules. These characteristics are a result of high surface area, mechanical stability and chemical stability, and excellent optical, electrical, and thermal properties. Their great and infinite functionalization potential also allows them to be integrated into several types of polymers, macromolecules, or other nanoparticles, leading to the fabrication of novel nanocarriers with enhanced biocompatibility and trigger-sensitive properties. Thus, numerous studies have been dedicated to graphene modification and functionalization. In the current review, we introduce graphene derivatives and different graphene-based nanomaterials utilized in drug delivery and discuss the most important advances in their functionalization and modification. Also, their potential and progress in an intelligent drug release in response to different types of stimuli either endogenous (pH, redox conditions, and reactive oxygen species (ROS)) or exogenous (temperature, near-infrared (NIR) radiation, and electric field) will be debated.

Photoresponsive Inorganic Nanomaterials in Oncology

The diagnosis and treatment of cancer are continuously evolving in search of more efficient, safe, and personalized approaches. Therapies based on nanoparticles or physical stimuli-responsive substances have shown great potential to overcome the inherent shortcomings of conventional cancer therapies. In fact, nanoparticles may increase the half-life of chemotherapeutic agents or promote the targeting in cancer tissues while physical stimuli-responsive substances are more effective and safer with respect to traditional chemotherapeutic agents because of the possibility to be switched on only when needed. These 2 approaches can be combined by exploiting the ability of some inorganic nanomaterials to be activated by light, ultrasounds, magnetic fields, or ionizing radiations. Albeit the development of stimuli-responsive materials is still at the early stages, research in this field is rapidly growing since they have important advantages with respect to organic nanoparticles or molecular substances, like higher stability, and higher efficiency in converting the stimulus in heat or, in some cases, reactive oxygen species. On the other hand, the translation process is slowed down by issues related to safety and quality of the formulations. This literature review summarizes the current advancements in this research field, analysing the most promising materials and applications.

Photodynamic and antibacterial studies of template-assisted Fe2O3-TiO2 nanocomposites

Fe₂O₃-TiO₂ (FT) nanocomposites were successfully synthesized by template-assisted precipitation reaction using Polyvinylpyrrolidone-Polyethylene glycol (PVP-PEG), Tween-80 (T-80) and Cetyltrimethylammomium bromide (CTAB) as templates. The prepared nanocomposites were characterized by XRD, SEM, EDX, UV-DRS, FT-IR, and FT-Raman spectroscopic analysis. The photohemolysis studies were done in human erythrocytes and the cell viability studies were done in HeLa cell lines under the irradiation of an LED light source. The photodynamic studies were performed under two different experimental conditions, such as varying concentrations as well as a time of irradiation. The nanocomposites exhibit significant photodynamic activity via the generation of reactive oxygen species (ROS) under the light source. The results show that the PVP-PEG-assisted Fe₂O₃-TiO₂ (FT-PVP-PEG) nanocomposite has more potential for photodynamic activity in the presence of an LED light source. Also, the antibacterial effect of the samples was investigated against gram-negative bacteria (Escherichia coli). Among all nanocomposites, FT-PVP-PEG shows remarkable antibacterial activity against E. coli. Moreover, the template-assisted nanocomposites protect the biomolecules from the toxicity generated by the magnetic nanoparticles (NPs). The template-assisted FT nanocomposites for the field of photodynamic activity have been experimentally shown for the first time.

Photoresponsive Nanocarriers Based on Lithium Niobate Nanoparticles for Harmonic Imaging and On-Demand Release of Anticancer Chemotherapeutics

Nanoparticle-based drug delivery systems have the potential for increasing the efficiency of chemotherapeutics by enhancing the drug accumulation at specific target sites, thereby reducing adverse side effects and mitigating patient acquired resistance. In particular, photo-responsive nanomaterials have attracted much interest due to their ability to release molecular cargos on demand upon light irradiation. In some settings, they can also provide complementary information by optical imaging on the (sub)cellular scale. We herein present a system based on lithium niobate harmonic nanoparticles (LNO HNPs) for the decoupled multi-harmonic cell imaging and near-infrared light-triggered delivery of an erlotinib derivative (ELA) for the treatment of epidermal growth factor receptor (EGFR)-overexpressing carcinomas. The ELA cargo was covalently conjugated to the surface of silica-coated LNO HNPs through a coumarinyl photo-cleavable linker, achieving a surface loading of the active molecule of 27 nmol/mg NPs. The resulting nanoconjugates (LNO-CM-ELA NPs) were successfully imaged upon pulsed laser excitation at 1250 nm in EGFR-overexpressing human prostate cancer cells DU145 by detecting the second harmonic emission at 625 nm, in the tissue transparency window. Tuning the laser at 790 nm resulted in the uncaging of the ELA cargo as a result of the second harmonic emission of the inorganic HNP core at 395 nm. This protocol induced a significant growth inhibition in DU145 cells, which was only observed upon specific irradiation at 790 nm, highlighting the promising capabilities of LNO-CM-ELA NPs for theranostic applications.

Indocyanine green conjugated phototheranostic nanoparticle for photodiagnosis and photodynamic reaciton

BACKGROUND

Phototheranostics represents a highly promising paradigm for cancer therapy, although selecting an appropriate optical imager and sensitizer for clinical use remains challenging.

METHODS

Liposomally formulated phospholipid-conjugated indocyanine green, denoted as LP-iDOPE, was developed as phototheranostic nanoparticle and its cancer imaging-mediated photodynamic reaction, defined as the immune response induced by photodynamic and photothermal effects, was evaluated with a near-infrared (NIR)-light emitting diode (LED) light irradiator.

RESULTS

Using in vivo NIR fluorescence imaging, we demonstrated that LP-iDOPE was selectively delivered to tumor sites with high accumulation and a long half-life. Following low-intensity NIR-LED light irradiation on the tumor region of LP-iDOPE accumulated, effector CD8⁺ T cells were activated at the secondary lymphoid organs, migrated, and subsequently released cytokines including interferon-γ and tumor necrosis factor-α, resulting in effective tumor regression.

CONCLUSIONS

Our anti-cancer strategy based on tumor-specific LP-iDOPE accumulation and low-intensity NIR-LED light irradiation to the tumor regions, i.e., photodynamic reaction, represents a promising approach to noninvasive cancer therapy.

Recent Advances in Targeted Nanotherapies for Ischemic Stroke

Ischemic stroke (IS) is a severe neurological disease caused by the narrowing or occlusion of cerebral blood vessels and is known for high morbidity, disability, and mortality rates. Clinically available treatments of stroke include the surgical removal of the thrombus and thrombolysis with tissue fibrinogen activator. Pharmaceuticals targeting IS are uncommon, and the development of new therapies is hindered by the low bioavailability and stability of many drugs. Nanomedicine provides new opportunities for the development of novel neuroprotective and thrombolytic strategies for the diagnosis and treatment of IS. Numerous nanotherapeutics with different physicochemical properties are currently being developed to facilitate drug delivery by accumulation and controlled release and to improve their restorative properties. In this review, we discuss recent developments in IS therapy, including assisted drug delivery and targeting, neuroprotection through regulation of the neuron environment, and sources of endogenous biomimetic specific targeting. In addition, we discuss the role and neurotoxic effects of inorganic metal nanoparticles in IS therapy. This study provides a theoretical basis for the utilization of nano-IS therapies that may contribute to the development of new strategies for a range of embolic diseases.

One stone, many birds: Recent advances in functional nanogels for cancer nanotheranostics

Inspired by the development of nanomedicine and nanotechnology, more and more possibilities in cancer theranostic have been provided in the last few years. Emerging therapeutic modalities like starvation therapy, chemodynamic therapy, and tumor oxygenation have been integrated with diagnosis, giving a plethora of theranostic nanoagents. Among all of them, nanogels (NGs) show superiority benefiting from their unique attributes: high stability, high water-absorption, large specific surface area, mechanical strength, controlled responsiveness, and high encapsulation capacity. There have been a vast number of investigations supporting various NGs combining drug delivery and multiple bioimaging techniques, encompassing photothermal imaging, photoacoustic imaging, fluorescent imaging, ultrasound imaging, magnetic resonance imaging, and computed tomography. This review summarizes recent advances in functional NGs for theranostic nanomedicine and discusses the challenges and future perspectives of this fast-growing field. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

Nanomedicine Penetration to Tumor: Challenges, and Advanced Strategies to Tackle This Issue

Nanomedicine has been under investigation for several years to improve the efficiency of chemotherapeutics, having minimal pharmacological effects clinically. Ineffective tumor penetration is mediated by tumor environments, including limited vascular system, rising cancer cells, higher interstitial pressure, and extra-cellular matrix, among other things. Thus far, numerous methods to increase nanomedicine access to tumors have been described, including the manipulation of tumor micro-environments and the improvement of nanomedicine characteristics; however, such outdated approaches still have shortcomings. Multi-functional convertible nanocarriers have recently been developed as an innovative nanomedicine generation with excellent tumor infiltration abilities, such as tumor-penetrating peptide-mediated transcellular transport. The developments and limitations of nanomedicines, as well as expectations for better outcomes of tumor penetration, are discussed in this review.

Contact-Free Remote Manipulation of Hydrogel Properties Using Light-Triggerable Nanoparticles: A Materials Science Perspective for Biomedical Applications

Considerable progress has been made in synthesizing "intelligent", biodegradable hydrogels that undergo rapid changes in physicochemical properties once exposed to external stimuli. These advantageous properties of stimulus-triggered materials make them highly appealing to diverse biomedical applications. Of late, research on the incorporation of light-triggered nanoparticles (NPs) into polymeric hydrogel networks has gained momentum due to their ability to remotely tune hydrogel properties using facile, contact-free approaches, such as adjustment of wavelength and intensity of light source. These multi-functional NPs, in combination with tissue-mimicking hydrogels, are increasingly being used for on-demand drug release, preparing diagnostic kits, and fabricating smart scaffolds. Here, the authors discuss the atomic behavior of different NPs in the presence of light, and critically review the mechanisms by which NPs convert light stimuli into heat energy. Then, they explain how these NPs impact the mechanical properties and rheological behavior of NPs-impregnated hydrogels. Understanding the rheological behavior of nanocomposite hydrogels using different sophisticated strategies, including computer-assisted machine learning, is critical for designing the next generation of drug delivery systems. Next, they highlight the salient strategies that have been used to apply light-induced nanocomposites for diverse biomedical applications and provide an outlook for the further improvement of these NPs-driven light-responsive hydrogels.

Intelligent and spatiotemporal drug release based on multifunctional nanoparticle-integrated dissolving microneedle system for synergetic chemo-photothermal therapy to eradicate melanoma

Cutaneous melanoma is one of the most common malignant skin cancer with high lethality. Chemotherapy and photothermal therapy are important and extensively studied treatment modalities for melanoma. However, these therapies still face some challenges, which severely restrict their further applications, such as unsatisfactory efficacy of monotherapy, nonspecific uptake and release during drug delivery, and unexpected adverse effects from system administration. Recently, the strategies of collaboration, functional modification, stimuli-responsive design, and topical administration all show great prospect for solving above problems. In this research, a multifunctional nanoparticle-integrated dissolving microneedle drug delivery system was constructed, in which the nanoparticles were prepared based on the framework with the incorporation of photothermal agent (CuS) into Zeolitic imidazolate framework-8 and functionalized by hyaluronic acid. This system can co-load multi-modal drugs, improve specific uptake and distribution of targeted tumor, deliver drug locally, and release drug intelligently and spatiotemporally, thereby promising a low-dose administration with high efficiency. The high inhibiting tumor performance and excellent systematic safety were verified both in vitro and in vivo. Together, this smart design overcame the drawbacks of monotherapy and conventional system administration. We believe the nanoparticle-integrated dissolving microneedles will be in prospect of clinical application for more superficial tumors with further delicate optimization. STATEMENT OF SIGNIFICANCE: Melanoma is one of the most common skin cancers with high lethality. Extensively studied chemotherapy and photothermal therapy still face some challenges, such as the limited therapeutic efficacy and the severe system adverse effects. In order to overcome these drawbacks, the multifunctional nanoparticle-integrated dissolving microneedles (DMNs) were designed. Especially, the nanoparticles could co-load multi-modal drugs, improve specific uptake, and release drug intelligently and spatiotemporally. The microneedles could increase the drug accumulation in tumor, thus achieving excellent therapeutic efficacy and reducing side effects. This system paved the way to a less invasive, more focused and efficient therapeutic strategy for melanoma therapy.

Current Clinical and Pre-Clinical Imaging Approaches to Study the Cancer-Associated Immune System

In the light of the success and the expected growth of its arsenal, immuno-therapy may become the standard neoadjuvant procedure for many cancers in the near future. However, aspects such as the identity, organization and the activation status of the peri- and intra-tumoral immune cells would represent important elements to weigh in the decision for the appropriate treatment. While important progress in non-invasive imaging of immune cells has been made over the last decades, it falls yet short of entering the clinics, let alone becoming a standard procedure. Here, we provide an overview of the different intra-vital imaging approaches in the clinics and in pre-clinical settings and discuss their benefits and drawbacks for assessing the activity of the immune system, globally and on a cellular level. Stimulated by further research, the future is likely to see many technological advances both on signal detection and emission as well as image specificity and resolution to tackle current hurdles. We anticipate that the ability to precisely determine an immune stage of cancer will capture the attention of the oncologist and will create a change in paradigm for cancer therapy.

Carbohydrate-based magnetic nanocomposites for effective cancer treatment

The treatment of cancer includes several conventional therapies like surgery, radiation, chemotherapy, etc. but mostly associated with limitations like off-targeted action, fatigue and organ toxicity. The emergence of nanotechnology-enabled drug delivery systems shows revolutionary development to overcome the limitations of such therapies. Magnetic nanocomposites are the new area of research that consists of nanoscale magnetic materials for triggering the release of active in response to an external magnetic field. For targeted drug delivery and enhancing the biocompatibility, effective functionalization of magnetic nanocomposites is required. Therefore, several biological molecules like carbohydrate polymers, proteins, nucleic acids, antibodies, etc. are used. This review article focuses on the insights of advances in the development of carbohydrate-based magnetic nanocomposites for safe and effective cancer treatment. Carbohydrate-based magnetic nanocomposites offer significant advantages like greater stability, higher biocompatibility and lower toxicity with better physicochemical properties such as higher magnetic moments and anisotropy, larger heating properties, etc. Magnetic nanocomposites explore in almost all the areas of cancer therapeutics for drug delivery carrier, as antineoplastic and MRI contrast agents and in photothermal, photodynamic and in combinational therapies for the development of safer nanocarriers. Such progressive trend of carbohydrate-based magnetic nanocomposites will encourage the researchers for better site-specific delivery with higher safety profile in cancer therapy.

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.

Graphene Oxide Composite for Selective Recognition, Capturing, Photothermal Killing of Bacteria over Mammalian Cells

The multifunctional photothermal therapy (PTT) platform with the ability to selectively kill bacteria over mammalian cells has received widespread attention recently. Herein, we prepared graphene oxide-amino(polyethyleneglycol) (GO-PEG-NH2) while using the hydrophobic interaction between heptadecyl end groups of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethyleneglycol)] (DSPE-PEG-NH2) and graphene oxide (GO). Based on GO-PEG-NH2, the versatile PTT system was constructed with simultaneous selective recognition, capturing, and photothermal killing of bacteria. When the cells undergo bacterial infection, owing to the poly(ethylene glycol) (PEG) chains and positively charged amino groups, GO-PEG-NH2 can specifically recognize and capture bacteria in the presence of cells. Meanwhile, the stable photothermal performance of GO-PEG-NH2 enables the captured bacteria to be efficiently photothermally ablated upon the irradiation of 808 nm laser. Besides, the GO-PEG-NH2 is highly stable in various biological media and it exhibits low cytotoxicity, suggesting that it holds great promise for biological applications. This work provides new insight into graphene-based materials as a PTT agent for the development of new therapeutic platforms.

Plasmonic Nanoassemblies: Tentacles Beat Satellites for Boosting Broadband NIR Plasmon Coupling Providing a Novel Candidate for SERS and Photothermal Therapy

Optical theranostic applications demand near-infrared (NIR) localized surface plasmon resonance (LSPR) and maximized electric field at nanosurfaces and nanojunctions, aiding diagnosis via Raman or optoacoustic imaging, and photothermal-based therapies. To this end, multiple permutations and combinations of plasmonic nanostructures and molecular "glues" or linkers are employed to obtain nanoassemblies, such as nanobranches and core-satellite morphologies. An advanced nanoassembly morphology comprising multiple linear tentacles anchored onto a spherical core is reported here. Importantly, this core-multi-tentacle-nanoassembly (CMT) benefits from numerous plasmonic interactions between multiple 5 nm gold nanoparticles (NPs) forming each tentacle as well as tentacle to core (15 nm) coupling. This results in an intense LSPR across the "biological optical window" of 650-1100 nm. It is shown that the combined interactions are responsible for the broadband LSPR and the intense electric field, otherwise not achievable with core-satellite morphologies. Further the sub 80 nm CMTs boosted NIR-surface-enhanced Raman scattering (SERS), with detection of SERS labels at 47 × 10^-9 m, as well as lower toxicity to noncancerous cell lines (human fibroblast Wi38) than observed for cancerous cell lines (human breast cancer MCF7), presents itself as an attractive candidate for use as biomedical theranostics agents.

Gold Nanoshell-Linear Tetrapyrrole Conjugates for Near Infrared-Activated Dual Photodynamic and Photothermal Therapies

Photodynamic therapy (PDT) is a treatment in which photoactive compounds delivered to cancerous tissues are excited with light and then transfer the absorbed energy to adjacent tissue oxygen molecules to generate toxic singlet oxygen (¹O₂). As ¹O₂ is produced only where light and photosensitizers (PSs) are combined, PDT holds promise as a minimally invasive, highly selective treatment for certain cancers. The practical application of PDT requires easily synthesized, water-soluble PSs that have low dark toxicities, high ¹O₂ quantum yields, and efficient absorption of 650-850 nm near-infrared (NIR) light, which deeply penetrates tissue. We recently developed a linear tetrapyrrole metal complex, Pd[DMBil1]-PEG₇₅₀, that meets most of these criteria. This complex is remarkably effective as a PS for PDT against triple-negative breast cancer (TNBC) cells but, critically, it does not absorb NIR light, which is necessary to treat deeper tumors. To enable NIR activation, we synthesized a new derivative, Pd[DMBil1]-PEG₅₀₀₀-SH, which bears a thiol functionality that facilitates conjugation to NIR-absorbing gold nanoshells (NSs). Upon excitation with pulsed 800 nm light, NSs emit two-photon-induced photoluminescence spanning 500-700 nm, which can sensitize the attached PSs to initiate PDT. Additionally, NSs produce heat upon 800 nm irradiation, endowing the NS-PS conjugates with an auxiliary photothermal therapeutic (PTT) capability. Here, we demonstrate that NS-PS conjugates are potent mediators of NIR-activated tandem PDT/PTT against TNBC cells in vitro. We show that Pd[DMBil1]-PEG₅₀₀₀-SH retains the photophysical properties of the parent Pd[DMBil1] complex, and that NS-PS generate ¹O₂ under pulsed 800 nm irradiation, confirming activation of the PSs by photoluminescence emitted from NSs. TNBC cells readily internalize NS PS conjugates, which generate reactive oxygen species in the cells upon pulsed NIR irradiation to damage DNA and induce apoptosis. Together, these findings demonstrate that exploiting photoluminescent NSs as carriers of efficient Pd[DMBil1] PSs is an effective strategy to enable NIR light-activated tandem PDT/PTT.

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.

Metal-based antibody drug conjugates. Potential and challenges in their application as targeted therapies in cancer

Antibody drug conjugates have emerged as a very attractive type of targeted therapy in cancer. They combine the antigen-targeting specificity of monoclonal antibodies (mAbs) with the cytotoxic potency of chemotherapeutics. This review focuses on antibody drug conjugates based on metal-containing cytotoxic payloads. We will also describe antibody drug conjugates (ADCs) in which a metal-based component (mostly metallic nanoparticles) exerts a relevant function in the ADC (for photodynamic or photothermal therapy, as air-plasma-enhancer or chemo-sensitizer, as carrier of other cytotoxic payloads or as an integral part of the linker structure). Challenges and opportunities to increase the translational potential of these ADCs will be discussed.

Core‑shell type thermo‑nanoparticles loaded with temozolomide combined with photothermal therapy in melanoma cells

A novel core-shell type thermo-nanoparticle (CSTNP) co-loaded with temozolomide (TMZ) and the fluorescein new indocyanine green dye IR820 (termed IT-CSTNPs) was designed and combined with a near-infrared (NIR) laser to realize its photothermal conversion. The IT-CSTNPs were prepared using a two-step synthesis method and comprised a thermosensitive shell and a biodegradable core. IR820 and TMZ were entrapped in the shell and the core, respectively. Dynamic light scattering results demonstrated that the average hydrodynamic size of the IT-CSTNPs was 196.4±3.1 nm with a ζ potential of −24.9±1.3 mV. The encapsulation efficiencies of TMZ and IR820 were 6.1 and 16.6%, respectively. Temperature increase curves under NIR laser irradiation indicated that the IT-CSTNPs exhibited the desired photothermal conversion efficiency. The in vitro drug release curves revealed a suitable release capability of IT-CSTNP under physiological conditions, whereas NIR laser irradiation accelerated the drug release. Inverted fluorescence microscopy and flow cytometry results revealed that the uptake of IT-CSTNPs by A375 melanoma cells occurred in a concentration-dependent manner. Confocal laser scanning microscopy results indicated that IT-CSTNPs entered tumour cells via endocytosis and were located in intercellular lysosomes. In summary, the present study explored the photothermal conversion capability, cellular uptake, and intracellular localization of IT-CSTNPs.

Anisotropic Plasmonic Metal Heterostructures as Theranostic Nanosystems for Near Infrared Light-Activated Fluorescence Amplification and Phototherapy

The development of sophisticated theranostic systems for simultaneous near infrared (NIR) fluorescence imaging and phototherapy is of particular interest. Herein, anisotropic plasmonic metal heterostructures, Pt end-deposited Au nanorods (PEA NRs), are developed to efficiently produce hot electrons under 808 nm laser irradiation, exhibiting the strong electric density. These hot electrons can release the heat through electron-phonon relaxation and form reactive oxygen species through chemical transformation, as a result of potent photothermal and photodynamic performance. Simultaneously, the confined electromagnetic field of PEA NRs can transfer energy to adjacent polyethylene glycol (PEG)-linked NIR fluorophores (CF) based on their energy overlap mechanism, leading to remarkable NIR fluorescence amplification in CF-PEA NRs. Various PEG linkers (1, 3.4, 5.0, and 10 kD) are employed to regulate the distance between CF and PEA NRs of CF-PEA NRs, and the maximum fluorescence intensity is achieved in CF5k-PEA NRs. After further attachment with i-motif DNA/Nrf2 siRNA chimera to simultaneously suppress both cellular antioxidant defense and hyperthermia resistance effects, the final biocompatible CF5k-bPEA@siRNA NRs present promising NIR fluorescence imaging ability and 808 nm laser-activated photothermal and photodynamic therapeutic effect in MCF7 cells and tumor-bearing mice, holding great potential for cancer therapy.

Redox-Activatable and Acid-Enhanced Nanotheranostics for Second Near-Infrared Photoacoustic Tomography and Combined Photothermal Tumor Therapy

Tumor phototheranostics in the second near-infrared window (NIR-II, 1000-1700 nm) holds great promise due to high spatiotemporal precision, enhanced penetration depth, and therapeutic efficacy. However, current "always-on" NIR-II phototheranostic agents remain restricted by the inherent nonspecificity from the pseudosignal readout and undesirable treatment-related side effects. To address these challenges, herein we explore an activatable and biocompatible nanotheranostics that generates diagnostic and therapeutic effects only after specific activation and enhancement by tumor microenvironmental redox and acid while keeping silent at normal tissues. Such an intelligent "turn-on" chromogenic nanotheranostics allows in vivo nearly zero-background photoacoustic tomography (PAT) and combined effective photothermal tumor therapy (PTT) both in the NIR-II range with minimal adverse effects. In light of the high sensitivity, superior penetration depth, and biocompatibility, this stimuli-activatable NIR-II photo-nanotheranostics provides broad prospects for the investigation and intervention of deep-tissue redox and acid-associated physiological and pathological events.

DNA-enabled rational design of fluorescence-Raman bimodal nanoprobes for cancer imaging and therapy

Recently, surface-enhanced Raman scattering nanoprobes have shown tremendous potential in oncological imaging owing to the high sensitivity and specificity of their fingerprint-like spectra. As current Raman scanners rely on a slow, point-by-point spectrum acquisition, there is an unmet need for faster imaging to cover a clinically relevant area in real-time. Herein, we report the rational design and optimization of fluorescence-Raman bimodal nanoparticles (FRNPs) that synergistically combine the specificity of Raman spectroscopy with the versatility and speed of fluorescence imaging. DNA-enabled molecular engineering allows the rational design of FRNPs with a detection limit as low as 5 × 10⁻¹⁵ M. FRNPs selectively accumulate in tumor tissue mouse cancer models and enable real-time fluorescence imaging for tumor detection, resection, and subsequent Raman-based verification of clean margins. Furthermore, FRNPs enable highly efficient image-guided photothermal ablation of tumors, widening the scope of the NPs into the therapeutic realm.

Currently available Raman scanners are limited in speed to acquire images of clinically relevant sizes in cancer imaging. Here, the authors developed a DNA based design principle for Raman-Fluorescence bimodal nanoparticles and demonstrate real-time, high precision image-guided tumor resections and photothermal ablation of cancer.

Pro- and anti-oxidant properties of near-infrared (NIR) light responsive carbon nanoparticles

Elemental carbon nanomaterials (ECNMs) are redox active agents that can be exploited to purposely modify the redox balance of cells. Both pro- or antioxidant properties have been reported. However, to the best of our knowledge, there are not comprehensive studies exploring both properties on the same material in view of a potential application in medicine. At the same time, the effect of the bulk structure on the pro/antioxidant properties is poorly known. Here, carbon nanoparticles (CNPs) derived by glucose with definite size and shape have been prepared, and their redox properties evaluated in cell free systems in the dark or following activation with a Near Infrared (NIR) laser beam (945 nm, 1.3 W/cm²). We found that, when irradiated with NIR, CNPs efficiently generate heat and singlet oxygen (¹O₂), a property that can be exploited for dual photo-thermal (PT)/photodynamic (PD) therapy in cancer. On the other hand, in the absence of photo-activation, CNPs react with both oxidant (hydroxyl radicals) and antioxidant (glutathione) species. When tested on a murine macrophages cell line (RAW 264.7) CNPs were clearly antioxidant. Furthermore, albeit efficiently internalized, CNPs do not exert cytotoxic effect up to 80 µg/ml and do not exacerbate TNF-α-mediated inflammation. Overall, the results reported herein suggest that CNPs may represent a new class of safe nanomaterials with potential applications in medicine.

Photothermal therapy and photoacoustic imaging via nanotheranostics in fighting cancer

The nonradiative conversion of light energy into heat (photothermal therapy, PTT) or sound energy (photoacoustic imaging, PAI) has been intensively investigated for the treatment and diagnosis of cancer, respectively. By taking advantage of nanocarriers, both imaging and therapeutic functions together with enhanced tumour accumulation have been thoroughly studied to improve the pre-clinical efficiency of PAI and PTT. In this review, we first summarize the development of inorganic and organic nano photothermal transduction agents (PTAs) and strategies for improving the PTT outcomes, including applying appropriate laser dosage, guiding the treatment via imaging techniques, developing PTAs with absorption in the second NIR window, increasing photothermal conversion efficiency (PCE), and also increasing the accumulation of PTAs in tumours. Second, we introduce the advantages of combining PTT with other therapies in cancer treatment. Third, the emerging applications of PAI in cancer-related research are exemplified. Finally, the perspectives and challenges of PTT and PAI for combating cancer, especially regarding their clinical translation, are discussed. We believe that PTT and PAI having noteworthy features would become promising next-generation non-invasive cancer theranostic techniques and improve our ability to combat cancers.

Acid-Triggered in Situ Aggregation of Gold Nanoparticles for Multimodal Tumor Imaging and Photothermal Therapy

Photothermal agents with high photothermal transfer efficiencies in the near-infrared (NIR) region are important for enhanced photothermal therapy (PTT) of tumors. Herein, we developed a strategy for the acid-triggered in situ aggregation of a system based on peptide-conjugated gold nanoparticles (GNPs). In an acidic environment, the GNPs formed large aggregates in solution, in cell lysates, and in tumor tissues, as observed by transmission electron microscopy (TEM). As a consequence of the aggregation, their UV-vis absorbance in the NIR region was greatly increased, and laser irradiation of the GNPs resulted in a dramatic increase in the temperatures of solutions and tumors that contained the GNP system. When exposed to NIR irradiation, the aggregates formed by the GNP system under acidic conditions were capable of producing a sufficient level of hyperthermia to destroy cancer cells both in vitro and in vivo. Interestingly, the GNP aggregates showed enhanced properties in multiple imaging modalities, including computed tomography (CT), photoacoustic (PA), and photothermal (PT) imaging. Thus, we have developed a novel probe for enhanced multimodal tumor imaging. These findings prove that a strategy involving the acid-triggered in situ aggregation of a GNP system can increase the photothermal transfer efficiency for low to high energy conversion, thus boosting the therapeutic specificity and antitumor efficacy of PTT and facilitating multimodal imaging.

NIR-Light- and pH-Responsive Graphene Oxide Hybrid Cyclodextrin-Based Supramolecular Hydrogels

Here, a novel triple-responsive graphene oxide hybrid supramolecular hydrogel based on the electrostatic self-assembly between graphene oxide and a quaternized polymer and the host-guest inclusion between α-cyclodextrins and poly(ethylene glycol) monomethyl ether (mPEG) was constructed. The quaternized polymer was synthesized by quaternization between pH-sensitive poly( N, N-dimethylaminoethyl methacrylate) and bromine end-capped poly(ethylene glycol) monomethyl ether. The supramolecular hydrogels prepared from the host-guest inclusion of poly(ethylene glycol) monomethyl ether and α-cyclodextrins would turn into a mobile sol phase when the temperature was increased above a certain temperature (Tgel-sol). Graphene oxide sheets not only acted as a core material to provide additional cross-linking but also absorbed NIR light and converted NIR light into heat to trigger the gel-sol transition. The constructed graphene oxide hybrid cyclodextrin-based supramolecular hydrogels could respond to NIR light, temperature, and pH, which could be beneficial for controlled release of cargoes and would hold great promise in the field of delivery systems.

Recent Advances in Carbon Nanomaterials for Cancer Phototherapy

Carbon nanomaterials have received great attention from the scientific community over the past few decades because of their unique physical and chemical properties. In this minireview, we will summarize the recent progress of the use of various carbon nanomaterials in the field of cancer phototherapy. The structural characteristics of each category and the surface functionalization strategies of these nanomaterials will be briefly introduced before focusing on their therapeutic applications. Recent advances on their use in photothermal therapy, photodynamic therapy, and combined phototherapies are presented. Moreover, a few challenges and perspectives on the development of carbon nanomaterials for future theranostics are also discussed.

External stimulus responsive inorganic nanomaterials for cancer theranostics

Cancer is a highly intelligent system of cells, that works together with the body to thrive and subsequently overwhelm the host in order for its survival. Therefore, treatment regimens should be equally competent to outsmart these cells. Unfortunately, it is not the case with current therapeutic practices, the reason why it is still one of the most deadly adversaries and an imposing challenge to healthcare practitioners and researchers alike. With rapid nanotechnological interventions in the medical arena, the amalgamation of diagnostic and therapeutic functionalities into a single platform, theranostics provides a never before experienced hope of enhancing diagnostic accuracy and therapeutic efficiency. Additionally, the ability of these nanotheranostic agents to perform their actions on-demand, i.e. can be controlled by external stimulus such as light, magnetic field, sound waves and radiation has cemented their position as next generation anti-cancer candidates. Numerous reports exist of such stimuli-responsive theranostic nanomaterials against cancer, but few have broken through to clinical trials, let alone clinical practice. This review sheds light on the pros and cons of a few such theranostic nanomaterials, especially inorganic nanomaterials which do not require any additional chemical moieties to initiate the stimulus. The review will primarily focus on preclinical and clinical trial approved theranostic agents alone, describing their success or failure in the respective stages.

Targeted Intracellular Delivery of Antibodies: The State of the Art

A dominant area of antibody research is the extension of the use of this mighty experimental and therapeutic tool for the specific detection of molecules for diagnostics, visualization, and activity blocking. Despite the ability to raise antibodies against different proteins, numerous applications of antibodies in basic research fields, clinical practice, and biotechnology are restricted to permeabilized cells or extracellular antigens, such as membrane or secreted proteins. With the exception of small groups of autoantibodies, natural antibodies to intracellular targets cannot be used within living cells. This excludes the scope of a major class of intracellular targets, including some infamous cancer-associated molecules. Some of these targets are still not druggable via small molecules because of large flat contact areas and the absence of deep hydrophobic pockets in which small molecules can insert and perturb their activity. Thus, the development of technologies for the targeted intracellular delivery of antibodies, their fragments, or antibody-like molecules is extremely important. Various strategies for intracellular targeting of antibodies via protein-transduction domains or their mimics, liposomes, polymer vesicles, and viral envelopes, are reviewed in this article. The pitfalls, challenges, and perspectives of these technologies are discussed.

Gold-nanobranched-shell based drug vehicles with ultrahigh photothermal efficiency for chemo-photothermal therapy

Development of combined chemo-photothermal nanoplatform is of great interest for enhancing antitumor efficacy. Herein, a multifunctional drug delivery system was synthesized based on gold-nanobranched coated betulinic acid liposomes (GNBS-BA-Lips) for chemo-photothermal synergistic therapy. In this system, GNBS-BA-Lips exhibited broad near-infrared (NIR) absorption, preferable photothermal response and good photostability under NIR irradiation. Importantly, the gold-nanobranched nanostructure possessed high photothermal conversion efficiency (η = 55.7%), and the temperature change (ΔT) reached 43.2 °C after laser irradiation for 5 min. Upon NIR irradiation, the nanocarriers apparently endowed higher cell uptake, resulting in an enhanced intracellular drug accumulation. Furthermore, the tumor growth inhibition ratio achieved from chemo-photothermal therapy of GNBS-BA-Lips was 86.9 ± 1.1%, which was higher than that of the chemotherapy or photothermal therapy alone, showing an outstanding synergistic anticancer effect. Our data suggested that the nanoplatform should be considered as a critical platform in the development of cancer multi-mode therapies.

AGuIX® from bench to bedside-Transfer of an ultrasmall theranostic gadolinium-based nanoparticle to clinical medicine

AGuIX^® are sub-5 nm nanoparticles made of a polysiloxane matrix and gadolinium chelates. This nanoparticle has been recently accepted in clinical trials in association with radiotherapy. This review will summarize the principal preclinical results that have led to first in man administration. No evidence of toxicity has been observed during regulatory toxicity tests on two animal species (rodents and monkeys). Biodistributions on different animal models have shown passive uptake in tumours due to enhanced permeability and retention effect combined with renal elimination of the nanoparticles after intravenous administration. High radiosensitizing effect has been observed with different types of irradiations in vitro and in vivo on a large number of cancer types (brain, lung, melanoma, head and neck…). The review concludes with the second generation of AGuIX nanoparticles and the first preliminary results on human.

pH- and Enzyme-Sensitive IR820-Paclitaxel Conjugate Self-Assembled Nanovehicles for Near-Infrared Fluorescence Imaging-Guided Chemo-Photothermal Therapy

The short lifetime and easy quick elimination of the near-infrared (NIR) dye new indocyanine green (IR820) in the body restrict its practical application as a photothermal agent in cancer therapy. Meanwhile, the drawback of poor water solubility of the chemotherapeutic drug paclitaxel (PTX) largely restricts its clinical applications. Herein, we, for the first time, combined IR820 and PTX in an "all-in-one" fluorescence imaging-guided chemo-photothermal therapy (PTT) platform by a rational design of a novel pH- and enzyme-sensitive IR820-PTX conjugate assembly. Specifically, the IR820-PTX conjugate nanoparticles exhibit an extremely high therapeutic agent content (IR820 and PTX, 95.7%). Besides the good stability in bloodstream, the IR820-PTX nanoparticles can target tumors for high accumulation via the enhanced permeation and retention effect. Particularly, our IR820-PTX nanoparticles simultaneously solve the obstacles of PTX poor solubility and the short lifetime of IR820 for cancer therapy. The simultaneous release of the free drug and dye can efficiently kill tumor cells by the combination of PTT and chemotherapy via NIR irradiation. Furthermore, the combined therapy can be imaging-guided by measuring the NIR fluorescence imaging resulting from the IR820 component. Therefore, our rationally designed pH- and enzyme-sensitive IR820-PTX conjugate nanoparticles provide an alternative "all-in-one" option for an efficient combinational dual-therapy and imaging.

Erythrocyte-Derived Theranostic Nanoplatforms for Near Infrared Fluorescence Imaging and Photodestruction of Tumors

Nanoparticles activated by near-infrared (NIR) excitation provide a capability for optical imaging and photodestruction of tumors. We have engineered optical nanoconstructs derived from erythrocytes, which are doped with the FDA-approved NIR dye, indocyanine green (ICG). We refer to these constructs as NIR erythrocyte-mimicking transducers (NETs). Herein, we investigate the phototheranostic capabilities of NETs for fluorescence imaging and photodestruction of SKBR3 breast cancer cells and subcutaneous xenograft tumors in mice. Our cellular studies demonstrate that NETs are internalized by these cancer cells and localized to their lysosomes. As evidenced by NIR fluorescence imaging and in vivo laser irradiation studies, NETs remain available within tumors at 24 h postintravenous injection. In response to continuous wave 808 nm laser irradiation at intensity of 680 mW/cm² for 10-15 min, NETs mediate the destruction of cancer cells and tumors in mice through synergistic photochemical and photothermal effects. We demonstrate that NETs are effective in mediating photoactivation of Caspase-3 to induce tumor apoptosis. Our results provide support for the effectiveness of NETs as theranostic agents for fluorescence imaging and photodestruction of tumors and their role in photoinduced apoptosis initiated by their localization to lysosomes.