Dual-stimuli responsive and reversibly activatable theranostic nanoprobe for precision tumor-targeting and fluorescence-guided photothermal therapy

Emerging trends on the uptake of fluorescent probes based on glucose analogs by cancer cells: From basic studies to therapeutics

The cancer cell metabolism, notably characterized by the Warburg effect, has been the focus of intense investigation regarding the mechanisms of the uptake of glucose analogs, opening up perspectives for diagnosis and treatment of cancer disease. In this review, we delve into the ever-evolving landscape of cancer research, centering on fluorescent probes based on glucose analogs. These analogs, resulting from modifications in the carbohydrate structure with functional groups, have stood out as versatile molecules in applications ranging from disease comprehension to therapeutic innovation, especially when combined with fluorescent compounds. Fluorescence-based assays have provided valuable contributions to the revelation of complex biological mechanisms in life sciences. This review presents selected studies from about the past six years up to 2024 related to the use of glucose-based fluorescent probes, for the investigation of their uptake profile as well as for therapeutic purposes. We believe that these investigations offer insights into the intricate interaction between glucose analogs and cancer cell metabolism, guiding future research and clinical applications in this field.

An Intramolecular Rotor-Bridged Dimeric Cyanine Photothermal Transducer for Efficient Near-Infrared II Fluorescence Imaging-Guided Mitochondria-Targeted Phototherapy

Near-infrared (NIR) heptamethine cyanine (HCy) dyes are promising photothermal transducers for image-guided cancer treatment owing to their prominent photophysical properties and high photothermal conversion ability. However, HCy photothermal transducers usually have poor photostability due to degradation induced by the self-generated reactive oxygen species. Herein, a novel mitochondria-targeting dimeric HCy dye, named dimeric oBHCy, is rationally designed, exhibiting strong near-infrared II (NIR-II) fluorescence emission, high photothermal conversion efficiency (PCE), and excellent photostability. The large π-conjugation and drastic intramolecular motion of the diphenol rotor in the dimeric oBHCy enhance the nonradiative energy dissipation and suppress the intersystem crossing process, thereby achieving a high PCE (49.2%) and improved photostability. Impressively, dimeric oBHCy can precisely target mitochondria and induce mitochondrial damage upon NIR light irradiation. Under the guidance of in vivo NIR-II fluorescence imaging, efficient NIR light-activated photothermal therapy of 4T1 breast tumors is accomplished with a tumor inhibitory rate of 96% following a single injection of the dimeric oBHCy. This work offers an innovative strategy for designing cyanine photothermal transducers with integrated NIR-II fluorescence and photothermal properties for efficient cancer theranostics.

Site-Specific Cascade-Activatable Fluorogenic Nanomicelles Enable Precision and Accuracy Imaging of Pulmonary Metastatic Tumor

The precise localization of metastatic tumors with subtle growth is crucial for timely intervention and improvement of tumor prognosis but remains a paramount challenging. To date, site-specific activation of fluorogenic probes for single-stimulus-based diagnosis typically targets an occult molecular event in a complex biosystem with limited specificity. Herein, we propose a highly specific site-specific cascade-activated strategy to enhance detection accuracy, aiming to achieve the accurate detection of breast cancer (BC) lung metastasis in a cascade manner. Specifically, cascade-activatable NIR fluorogenic nanomicelles HPNs were constructed using ultra-pH-sensitive (UPS) block copolymers as carriers and nitroreductase (NTR)-activated fluorogenic reporters. HPNs exhibit programmable cascade response characteristics by first instantaneous dissociating under in situ tumor acidity, facilitating deep tumor penetration followed by selective fluorescence activation through NTR-mediated enzymatic reaction resulting in high fluorescence ON/OFF contrast. Notably, this unique feature of HPNs enables high-precision diagnosis of orthotopic BC as well as its lung metastases with a remarkable signal-to-background ratio (SBR). This proposed site-specific cascade activation strategy will offer opportunities for a specific diagnosis with high signal fidelity of various insidious metastatic lesions in situ across different diseases.

Biomimetic Ghost Nanomedicine-Based Optotheranostics for Cancer

Theranostic medicine combines diagnostics and therapeutics, focusing on solid tumors at minimal doses. Optically activated photosensitizers are significant examples owing to their photophysical and chemical properties. Several optotheranostics have been tested that convert light to imaging signals, therapeutic radicals, and heat. Upon light exposure, conjugated photosensitizers kill tumor cells by producing reactive oxygen species and heat or by releasing cancer antigens. Despite clinical trials, these molecularly conjugated photosensitizers require protection from their surroundings and a localized direction for site-specific delivery during blood circulation. Therefore, cell membrane biomimetic ghosts have been proposed for precise and safe delivery of these optically active large molecules, which are clinically relevant because of their biocompatibility, long circulation time, bypass of immune cell recognition, and targeting ability. This review focuses on the role of biomimetic nanoparticles in the treatment and diagnosis of tumors through light-mediated diagnostics and therapy, providing insights into their preclinical and clinical status.

Enhancing MRI through high loading of superparamagnetic nanogels with high sensitivity to the tumor environment

Tumors pose a significant threat to human health, and their occurrence and fatality rates are on the rise each year. Accurate tumor diagnosis is crucial in preventing untimely treatment and late-stage metastasis, thereby reducing mortality. To address this, we have developed a novel type of hybrid nanogel called γ-Fe2O3@PNIPAM/PAm/CTS, which contains iron oxide nanoparticles and poly(N-isopropyl acrylamide)/polyacrylamide/chitosan. The rationale for this study relies on the concept that thermosensitive PNIPAM has the ability to contract when exposed to elevated temperature conditions found within tumors. This contraction leads to a dense clustering of the high-loading γ-Fe2O3 nanoparticles within the nanogel, thus greatly enhancing the capabilities of MRI. Additionally, the amino groups in chitosan on the particle surface can be converted into ammonium salts under mildly acidic conditions, allowing for an increase in the charge of the nanogel specifically at the slightly acidic tumor site. Consequently, it promotes the phagocytosis of tumor cells and effectively enhances the accumulation and retention of nanogels at the tumor site. The synthesis of the hybrid nanogels involves a surfactant-free emulsion copolymerization process, where vinyl-modified γ-Fe2O3 superparamagnetic nanoparticles are copolymerized with the monomers in the presence of chitosan. We have optimized various reaction parameters to achieve a high loading content of the superparamagnetic nanoparticles, reaching up to 60%. The achieved r 2 value of 517.74 mM-1 S-1 significantly surpasses that of the clinical imaging contrast agent Resovist (approximately 151 mM-1 S-1). To assess the performance of these magnetic nanogels, we conducted experiments using Cal27 oral tumors and 4T1 breast tumors in animal models. The nanogels exhibited temperature- and pH-sensitivity, enabling magnetic targeting and enhancing diagnosis through MRI. The results demonstrated the potential of these hybrid nanogels as contrast agents for magnetic targeting in biomedical applications.

Acid-Triggered Degradation of Three-In-One Ag2S Quantum Dots for In Situ Ratiometric NIR-II Fluorescence Imaging-Guided Ion/Gas Combination Therapy

Smart theranostic nanoprobes with the integration of multiple therapeutic modalities are preferred for precise diagnosis and efficient therapy of tumors. However, it remains a big challenge to arrange the imaging and two or more kinds of therapeutic agents without weakening the intended performances. In addition, most existing fluorescence (FL) imaging agents suffer from low spatiotemporal resolution due to the short emission wavelength (<900 nm). Here, novel three-in-one Ag2S quantum dot (QD)-based smart theranostic nanoprobes were proposed for in situ ratiometric NIR-II FL imaging-guided ion/gas combination therapy of tumors. Under the acidic tumor microenvironment, three-in-one Ag2S QDs underwent destructive degradation, generating toxic Ag+ and H2S. Meanwhile, their FL emission at 1270 nm was weakened. Upon introduction of a downconversion nanoparticle (DCNP) as the delivery carrier and NIR-II FL reference signal unit, the formed Ag2S QD-based theranostic nanoprobes could achieve precise diagnosis of tumors through ratiometric NIR-II FL signals. Also, the generated Ag+ and H2S enabled specific ion/gas combination therapy toward tumors. By combining the imaging and therapeutic functions, three-in-one Ag2S QDs may open a simple yet reliable avenue to design theranostic nanoprobes.

A follicle-stimulating hormone receptor-targeted near-infrared fluorescent probe for tumor-selective imaging and photothermal therapy

Late detection, peritoneal dissemination, chemoresistance and weak response to targeted therapeutics lead to high mortality in ovarian cancer. More efficient and specific tumor imaging and therapeutic agents are needed to improve the resection rate of surgery and to eliminate residual disease. The expression patterns of follicle-stimulating hormone (FSH) receptor make it a suitable target for ovarian cancer. Here, we report a strategy to develop an organic near-infrared probe for FSH receptor-targeted tumor imaging and photothermal therapy. The FSH-Rh760 probe was conjugated from the Rh760 fluorophore with the FSH β subunit 33-53 peptide. FSH-Rh760 specifically distinguished peritoneal metastatic ovarian cancerous foci from surrounding normal tissues with a high tumor-to-background ratio. The fluorescence signals in tumors peaked at 2 h and were cleared at 120 h postinjection. FSH-Rh760 treatment rapidly increased the abdomen temperature of mice up to ∼43 °C upon exposure to a near-infrared laser and effectively suppressed peritoneal tumor growth with tumor specificity. No significant systemic toxicities were observed. This study demonstrates the targeting ability and biocompatibility of FSH receptor-targeted theranostics and highlights its potential for clinical application in imaging-guided precision tumor resection and photothermal therapy to eliminate cancer lesions intraoperatively and postoperatively.

Tumor microenvironment-activated theranostic nanoreactor for NIR-II Photoacoustic imaging-guided tumor-specific photothermal therapy

Theranostic agents that can be sensitively and specifically activated by the tumor microenvironment (TME) have recently attracted considerable attention. In this study, TME-activatable 3,3',5,5'-tetramethylbenzidine (TMB)-copper peroxide (CuO2)@poly(lactic-co-glycolic acid) (PLGA)@red blood cell membrane (RBCM) (TCPR) nanoparticles (NPs) for second near-infrared photoacoustic imaging-guided tumor-specific photothermal therapy were developed by co-loading CuO2 NPs and TMB into PLGA camouflaged by RBCMs. As an efficient H2O2 supplier, once exposed to a proton-rich TME, CuO2 NPs can generate H2O2 and Cu2+, which are further reduced to Cu+ by endogenous glutathione. Subsequently, the Cu+-mediated Fenton-like reaction produces cytotoxic ·OH to kill the cancer cells and induce TMB-mediated photoacoustic and photothermal effects. Combined with the RBCM modification-prolonged blood circulation, TCPR NPs display excellent specificity and efficiency in suppressing tumor growth, paving the way for more accurate, safe, and efficient cancer theranostics.

The Application of Nanotechnological Therapeutic Platforms against Gynecological Cancers

Gynecological cancers (GCs), ovarian, cervical, and endometrial/uterine cancers, are often associated with poor outcomes. Despite the development of several therapeutic modalities against GCs, the effectiveness of the current therapeutic approaches is limited due to their side effects, low therapeutic index, short halflife, and resistance to therapy. To overcome these limitations, nano delivery-based approaches have been introduced with the potential of targeted delivery, reduced toxicity, controlled release, and improved bioavailability of various cargos. This review summarizes the application of different nanoplatforms, such as lipid-based, metal- based, and polymeric nanoparticles, to improve the chemo/radio treatments of GC. In the following work, the use of nanoformulated agents to fight GCs has been mentioned in various clinical trials. Although nanosystems have their own challenges, the knowledge highlighted in this article could provide deep insight into translations of NPs approaches to overcome GCs.

Multi-Stimuli-Responsive and Cell Membrane Camouflaged Aggregation-Induced Emission Nanogels for Precise Chemo-photothermal Synergistic Therapy of Tumors

Targeted and controllable drug release at lesion sites with the aid of visual navigation in real-time is of great significance for precise theranostics of cancers. Benefiting from the marvelous features (e.g., bright emission and phototheranostic effects in aggregates) of aggregation-induced emission (AIE) materials, constructing AIE-based multifunctional nanocarriers that act as all-arounders to integrate multimodalities for precise theranostics is highly desirable. Here, an intelligent nanoplatform (P-TN-Dox@CM) with homologous targeting, controllable drug release, and in vivo dual-modal imaging for precise chemo-photothermal synergistic therapy is proposed. AIE photothermic agent (TN) and anticancer drug (Dox) are encapsulated in thermo-/pH-responsive nanogels (PNA), and the tumor cell membranes are camouflaged onto the surface of nanogels. Active targeting can be realized through homologous effects derived from source tumor cell membranes, which advantageously elevates the specific drug delivery to tumor sites. After being engulfed into tumor cells, the nanogels exhibit a burst drug release at low pH. The near-infrared (NIR) photoinduced local hyperthermia can activate severe cytotoxicity and further accelerate drug release, thus generating enhanced synergistic chemo-photothermal therapy to thoroughly eradicate tumors. Moreover, P-TN-Dox@CM nanogels could achieve NIR-fluorescence/photothermal dual-modal imaging to monitor the dynamic distribution of therapeutics in real-time. This work highlights the great potential of smart P-TN-Dox@CM nanogels as a versatile nanoplatform to integrate multimodalities for precise chemo-photothermal synergistic therapy in combating cancers.

Exploration of inorganic nanoparticles for revolutionary drug delivery applications: a critical review

The nanosystems for delivering drugs which have evolved with time, are being designed for greater drug efficiency and lesser side-effects, and are also complemented by the advancement of numerous innovative materials. In comparison to the organic nanoparticles, the inorganic nanoparticles are stable, have a wide range of physicochemical, mechanical, magnetic, and optical characteristics, and also have the capability to get modified using some ligands to enrich their attraction towards the molecules at the target site, which makes them appealing for bio-imaging and drug delivery applications. One of the strong benefits of using the inorganic nanoparticles-drug conjugate is the possibility of delivering the drugs to the affected cells locally, thus reducing the side-effects like cytotoxicity, and facilitating a higher efficacy of the therapeutic drug. This review features the direct and indirect effects of such inorganic nanoparticles like gold, silver, graphene-based, hydroxyapatite, iron oxide, ZnO, and CeO2 nanoparticles in developing effective drug carrier systems. This article has remarked the peculiarities of these nanoparticle-based systems in pulmonary, ocular, wound healing, and antibacterial drug deliveries as well as in delivering drugs across Blood-Brain-Barrier (BBB) and acting as agents for cancer theranostics. Additionally, the article sheds light on the plausible modifications that can be carried out on the inorganic nanoparticles, from a researcher's perspective, which could open a new pathway.

Bioinspired and biomimetic cancer-cell-derived membrane nanovesicles for preclinical tumor-targeted nanotheranostics

Bioinspired cell-membrane-camouflaged nanohybrids have been proposed to enhance tumor targeting by harnessing their immune escape and self-recognition abilities. In this study, we introduce cancer-cell-derived membrane nanovesicles (CCMVs) integrated with gold nanorods (AuVNRs) in addition to therapeutic and imaging cargos such as doxorubicin and indocyanine green. This approach enhances targeted tumor imaging and enables synergistic chemo-phototherapeutics for solid tumors. CCMVs demonstrate significant tumor penetration and retention, serving as nanotheranostics with accessible surface biomarkers, biomimicking properties, and homologous targeting abilities. By evading uptake by the mononuclear phagocytic system, CCMVs can diffuse into the deep tumor core, leading to precise tumor reduction while preserving the surrounding healthy tissues. Notably, intravenous administration of these theranostic agents ensures biocompatibility, as evidenced by a survival period of approximately two months (up to 63 days) without any observed side effects. Our findings underscore the diagnostic and therapeutic potential of this biomimetic nanotheranostics platform.

Recyclable and Robust Optical Nanoprobes with Engineered Enzymes for Sustainable Serodiagnostics

Recyclable fluorescence assays that can be stored at room temperature would greatly benefit biomedical diagnostics by bringing sustainability and cost-efficiency, especially for point-of-care serodiagnostics in developing regions. Here, a general strategy is proposed to generate recyclable fluorescent probes by using engineered enzymes with enhanced thermo-/chemo-stability, which maintains an outstanding serodiagnostic performance (accuracy >95%) after 10 times of recycling as well as after storage at elevated temperatures (37 °C for 10 days). With these three outstanding properties, recyclable fluorescent probes can be designed to detect various biomarkers of clinical importance by using different enzymes.

A dye-quenched/sensitized switching upconversion nanoprobe for high-contrast mapping of the pH-related tumor microenvironment

Nanoprobes based on lanthanide-doped upconversion nanoparticles (UCNPs) exhibit promising potential in bioimaging and biosensing due to their unique optical properties. However, conventional UCNP nanoprobes based on the dye quenching effect are still limited in biosensing due to their low upconversion efficiency. The advent of dye-sensitized upconversion has resulted in nanoprobes with significantly enhanced efficiency; however, these still suffer from a high initial emissive background. In view of this, herein, we have constructed a dye-quenched/sensitized switching upconversion nanoprobe for high-contrast imaging of the pH-related tumor microenvironment. Under normal conditions, the luminescence of the nanoprobe at 540 nm (UCL540) was significantly quenched by the employed dye. Upon being triggered by an acid, the dye would switch to its fluorescent form to sensitize the luminescence of UCNPs, affording a significant enhancement of UCL540. The switching from dye-quenched UCL to dye-sensitized UCL jointly enables the detection of a high signal-to-background ratio (high up to 50), allowing for high-contrast mapping of the tumor specific acidic microenvironment in vivo. We believe that this nanoplatform holds considerable promise for acid-related sensing.

Neutrophil membrane-based nanotherapeutics: Propitious paradigm shift in the management of cancer

Cancer is the leading cause of death across the globe, with 19.3 million new cancer cases and 10 million deaths in the year 2020. Conventional treatment modalities have numerous pitfalls, such as off-site cytotoxicity and poor bioavailability. Nanocarriers (NCs) have been explored to deliver various therapeutic moieties such as chemotherapeutic agents and photothermal agents, etc. However, several limitations, such as rapid clearance by the reticuloendothelial system, poor extravasation into the tumor microenvironment, and low systemic half-life are roadblocks to successful clinical translation. To circumvent the pitfalls of currently available treatment modalities, neutrophil membrane (NM)-based nanotherapeutics have emerged as a promising platform for cancer management. Their versatile features such as natural tumor tropism, tumor-specific accumulation, and prevention from rapid clearance owing to their autologous nature make them an effective anticancer NCs. In this manuscript, we have discussed various methods for isolation, coating and characterization of NM. We have discussed the role of NM-coated nanotherapeutics as neoadjuvant and adjuvant in different treatment modalities, such as chemotherapy, photothermal and photodynamic therapies with rationales behind their inclusion. Clinical hurdles faced during the bench-to-bedside translation with possible solutions have been discussed. We believe that in the upcoming years, NM-coated nanotherapeutics will open a new horizon in cancer management.

Revolutionizing cancer treatment: nanotechnology-enabled photodynamic therapy and immunotherapy with advanced photosensitizers

Nanotechnology-enhanced photodynamic therapy (PDT) and immunotherapy are emerging as exciting cancer therapeutic methods with significant potential for improving patient outcomes. By combining these approaches, synergistic effects have been observed in preclinical studies, resulting in enhanced immune responses to cancer and the capacity to conquer the immunosuppressive tumor microenvironment (TME). Despite challenges such as addressing treatment limitations and developing personalized cancer treatment strategies, the integration of nanotechnology-enabled PDT and immunotherapy, along with advanced photosensitizers (PSs), represents an exciting new avenue in cancer treatment. Continued research, development, and collaboration among researchers, clinicians, and regulatory agencies are crucial for further advancements and the successful implementation of these promising therapies, ultimately benefiting cancer patients worldwide.

Three Strategies in Engineering Nanomedicines for Tumor Microenvironment-Enabled Phototherapy

Canonical phototherapeutics have several limitations, including a lack of tumor selectivity, nondiscriminatory phototoxicity, and tumor hypoxia aggravation. The tumor microenvironment (TME) is characterized by hypoxia, acidic pH, and high levels of H2 O2 , GSH, and proteases. To overcome the shortcomings of canonical phototherapy and achieve optimal theranostic effects with minimal side effects, unique TME characteristics are employed in the development of phototherapeutic nanomedicines. In this review, the effectiveness of three strategies for developing advanced phototherapeutics based on various TME characteristics is examined. The first strategy involves targeted delivery of phototherapeutics to tumors with the assistance of TME-induced nanoparticle disassembly or surface modification. The second strategy involves near-infrared absorption increase-induced phototherapy activation triggered by TME factors. The third strategy involves enhancing therapeutic efficacy by ameliorating TME. The functionalities, working principles, and significance of the three strategies for various applications are highlighted. Finally, possible challenges and future perspectives for further development are discussed.

The Efficacy of Zinc Phthalocyanine Nanoconjugate on Melanoma Cells Grown as Three-Dimensional Multicellular Tumour Spheroids

Melanoma remains a major public health concern that is highly resistant to standard therapeutic approaches. Photodynamic therapy (PDT) is an underutilised cancer therapy with an increased potency and negligible side effects, and it is non-invasive compared to traditional treatment modalities. Three-dimensional multicellular tumour spheroids (MCTS) closely resemble in vivo avascular tumour features, allowing for the more efficient and precise screening of novel anticancer agents with various treatment combinations. In this study, we utilised A375 human melanoma spheroids to screen the phototoxic effect of zinc phthalocyanine tetrasulfonate (ZnPcS4) conjugated to gold nanoparticles (AuNP). The nanoconjugate was synthesised and characterised using ultraviolet-visible spectroscopy, a high-resolution transmission electron microscope (TEM), dynamic light scattering (DLS), and zeta potential (ZP). The phototoxicity of the nanoconjugate was tested on the A375 MCTS using PDT at a fluency of 10 J/cm2. After 24 h, the cellular responses were evaluated via microscopy, an MTT viability assay, an ATP luminescence assay, and cell death induction using annexin propidium iodide. The MTT viability assay demonstrated that the photoactivated ZnPcS4, at a concentration of 12.73 µM, caused an approximately 50% reduction in the cell viability of the spheroids. When conjugated to AuNPs, the latter significantly increased the cellular uptake and cytotoxicity in the melanoma spheroids via the induction of apoptosis. This novel Zinc Phthalocyanine Nanoconjugate shows promise as a more effective PDT treatment modality.

Yb-Gd Codoped Hydroxyapatite as a Potential Contrast Agent for Tumor-Targeted Biomedical Applications

Recently, various nanomaterials based on hydroxyapatite (HAp) have been developed for bioimaging applications. In particular, HAp doped with rare-earth elements has attracted significant attention, owing to its enhanced bioactivity and imaging properties. In this study, the wet precipitation method was used to synthesize HAp codoped with Yb and Gd. The synthesized Ybx-Gdx-HAp nanoparticles (NPs) were characterized via various techniques to analyze the crystal phase, functional groups, thermal characteristics, and particularly, the larger surface area. The IR783 fluorescence dye and a folic acid (FA) receptor were conjugated with the synthesized Ybx-Gdx-HAp NPs to develop an effective imaging contrast agent. The developed FA/IR783/Yb-Gd-HAp nanomaterial exhibited improved contrast, sensitivity, and tumor-specific properties, as demonstrated by using the customized LUX 4.0 fluorescence imaging system. An in vitro cytotoxicity study was performed to verify the biocompatibility of the synthesized NPs using MTT assay and fluorescence staining. Photodynamic therapy (PDT) was also applied to determine the photosensitizer properties of the synthesized Ybx-Gdx-HAp NPs. Further, reactive oxygen species generation was confirmed by Prussian blue decay and a 2',7'-dichlorofluorescin diacetate study. Moreover, MDA-MB-231 breast cancer cells were used to evaluate the efficiency of Ybx-Gdx-HAp NP-supported PDT.

Enzyme-Instructed Aggregation/Dispersion of Fluorophores for Near-Infrared Fluorescence Imaging In Vivo

Near-infrared (NIR) fluorescence is a noninvasive, highly sensitive, and high-resolution modality with great potential for in vivo imaging. Compared with "Always-On" probes, activatable NIR fluorescent probes with "Turn-Off/On" or "Ratiometric" fluorescent signals at target sites exhibit better signal-to-noise ratio (SNR), wherein enzymes are one of the ideal triggers for probe activation, which play vital roles in a variety of biological processes. In this review, we provide an overview of enzyme-activatable NIR fluorescent probes and concentrate on the design strategies and sensing mechanisms. We focus on the aggregation/dispersion state of fluorophores after the interaction of probes and enzymes and finally discuss the current challenges and provide some perspective ideas for the construction of enzyme-activatable NIR fluorescent probes.

Learning from human metabolism for nanomedicine: a convertible bismuth-agent for tumour-selective theranostics

Tumour-selective theranostic agents have attracted considerable interest over the past decade in oncology owing to their extraordinary anticancer efficacy. However, it still remains a challenge to develop theranostic agents balancing biocompatibility, multidimensional theranostics, tumour-selectivity, and simple components. Inspired by the metabolic pathways of exogenous sodium selenite against selenium-deficient diseases, reported here is the first convertible bismuth-based agent for tumour-selective theranostic functionalities. The specifically overexpressed substances in tumour tissue enable it to act as a natural reactor for the conversion from bismuth selenite to bismuth selenide, activating the theranostic functionalities specifically in tumour tissues. The converted product exhibits excellent multidimensional imaging-guided therapy. This study not only demonstrates a simple agent with both biocompatibility and sophisticated tumour-selective theranostic functionalities, but also pioneers a new approach from emulating nature towards oncological theranostic applications.

Programmed-stimuli responsive carrier-free multidrug delivery system for highly efficient trimodal combination therapy

Programmed response, carrier-free, and multimodal therapy drug delivery systems (DDS) are promising solutions to multidirectional cytotoxic effects, inefficient antitumor, and severe side effects for cancer therapy. Here, three widely used clinical drugs, interferon α1b (IFNα1b), indocyanine green (ICG), and doxorubicin (DOX), were prepared into carrier-free DDS IFNα1b-ICG-DOX (IID) by a simple one-step method without additional any reagents. IID can achieve smart and programmed DDS by combining low pH and near-infrared (NIR) light stimuli-responsive controlled release. In pH = 7.4 environments, our IID is about 380 nm in size with negative charge rounded particles; while they enter into the acid environment (pH < 7), hydrogen ions (H⁺) trigger DOX release, their size becomes larger and the surface charge turns positive. These larger particles are rapidly disintegrated after exposure to NIR light and then the remaining DOX, IFNα1b, and ICG are released. In vivo, the IID with larger size and positive charge resulting from low pH is is easy to accumulate in tumor tissue. Tumors can be exposed to NIR light when needed to control the release of these three drugs. Hence, DOX, ICG, and IFNα1b can be enriched in the tumor to the high efficiency of combined chemotherapy, photothermal therapy, and immunotherapy.

Pt nanozyme-bridged covalent organic framework-aptamer nanoplatform for tumor targeted self-strengthening photocatalytic therapy

Covalent organic frameworks (COFs) have emerged as a promising platform for nanomedicine, while developing multifunctional COF nanoplatforms remains challenging due to the lack of efficient strategies for COF modification. Herein, we propose a nanozyme bridging (NZB) strategy for COF functionalization. Platinum nanoparticles (Pt NPs) as catalase mimics were in situ grown on the surface of COF NPs without reducing their drug loading capacity (CP), and thiol-terminated aptamer was further densely decorated onto CP NPs via a stable Pt-S bond (CPA). Pt nanozyme engineering and aptamer functionalization rendered the nanoplatform with excellent photothermal conversion, tumor targeting, and catalase-like catalytic performances. Using clinical-approved photosensitizer indocyanine green (ICG) as a model drug, we fabricated a nanosystem (ICPA) for tumor-targeted self-strengthening therapy. ICPA can effectively accumulate into tumor tissue and relieve the hypoxia microenvironment by decomposing the overexpressed H₂O₂ and generating O₂. Under monowavelength NIR light irradiation, the catalase-like catalytic and singlet oxygen generation activities of ICPA can be significantly strengthened, leading to admirable photocatalytic treatment effects against malignant cells as well as tumor-bearing mice in a self-strengthening manner.

"Electron Transport Chain Interference" Strategy of Amplified Mild-Photothermal Therapy and Defect-Engineered Multi-Enzymatic Activities for Synergistic Tumor-Personalized Suppression

Arming activatable mild-photothermal therapy (PTT) with the property of relieving tumor thermotolerance holds great promise for overcoming traditional mild PTT limitations such as thermoresistance, insufficient therapeutic effect, and off-target heating. Herein, a mitochondria-targeting, defect-engineered AFCT nanozyme with enhanced multi-enzymatic activity was elaborately designed as a tumor microenvironment (TME)-activatable phototheranostic agent to achieve remarkable anti-tumor therapy via "electron transport chain (ETC) interference and synergistic adjuvant therapy". Density functional theory calculations revealed that the synergistic effect among multi-enzyme active centers endows the AFCT nanozymes with excellent catalytic activity. In TME, open sources of H₂O₂ can be achieved by superoxide dismutase-mimicking AFCT nanozymes. In response to the dual stimuli of H₂O₂ and mild acidity, the peroxidase-mimicking activity of AFCT nanozymes not only catalyzes the accumulation of H₂O₂ to generate ·OH but also converts the loaded 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) into its oxidized form with strong near-infrared absorption, specifically unlocking its photothermal and photoacoustic imaging properties. Intriguingly, the undesired thermoresistance of tumor cells can be greatly alleviated owing to the reduced expression of heat shock proteins enabled by NADH POD-mimicking AFCT-mediated NADH depletion and consequent restriction of ATP supply. Meanwhile, the accumulated ·OH can facilitate both apoptosis and ferroptosis in tumor cells, resulting in synergistic therapeutic outcomes in combination with TME-activated mild PTT.

Remodeling Tumor Immunogenicity with Dual-Activatable Binary CRISPR Nanomedicine for Cancer Immunotherapy

The specific recognition of cancer cells by the body's immune system is an essential step in initiating antitumor immunity. However, the decreased expression of major histocompatibility complex class I (MHC-1) and overexpression of programmed death ligand 1 (PD-L1) causes insufficient tumor-associated antigens presentation and inactivation of T cells, which accounts for poor immunogenicity. To remodel tumor immunogenicity, herein, a dual-activatable binary CRISPR nanomedicine (DBCN) that can efficiently deliver a CRISPR system into tumor tissues and specifically control its activation is reported. This DBCN is made of a thioketal-cross-linked polyplex core and an acid-detachable polymer shell, which can maintain stability during blood circulation, while detaching a polymer shell to facilitate the cellular internalization of the CRISPR system after entering tumor tissues and ultimately activating gene editing under exogenous laser irradiation, thereby maximizing the therapeutic benefits and reducing potential safety concerns. With the collaborative application of multiple CRISPR systems, DBCN efficiently corrects both dysregulation of MHC-1 and PD-L1 expression in tumors, thus initiating robust T cell-dependent antitumor immune responses to inhibit malignant tumor growth, metastasis, and recurrence. Given the increasing abundance of CRISPR toolkits, this research provides an appealing therapeutic strategy and a universal delivery platform to develop more advanced CRISPR-based cancer treatments.

Multi-stimuli-responsive molecular fluorescent probes for bioapplications

Stimuli-responsive fluorescent probes have been widely utilized in detecting the physiological and pathological states of living systems. Numerous stimuli-responsive fluorescent probes have been developed due to their advantages of good sensitivity, high resolution, and high contrast fluorescent signals. In this feature article, the progress of multi-stimuli-responsive probes, including organic molecules and metal complexes, for the detection of various biomarkers for bio-applications is summarized. The feature article focuses on the applications of organic-molecule- and metal-complex-based molecular probes in biological systems for detecting different biomarkers of cancer or other diseases. The current challenges and potential future directions of these probes for applications in biological systems are also discussed.

Tumor-Specific NIR-Activatable Nanoreactor for Self-Enhanced Multimodal Imaging and Cancer Phototherapy

Responsive nanosystems for tumor treatment with high specificity and sensitivity have aroused great attention. Herein, we develop a tumor microenvironment responsive and near-infrared (NIR)-activatable theranostic nanoreactor for imaging-guided anticancer therapy. The nanoreactor (SnO2-x@AGP) is comprised of poly(vinylpyrrolidine) encapsulated hollow mesoporous black SnO2-x nanoparticles coloaded with glucose oxidase (GOx) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The constructed nanoreactor can be specifically activated through endogenous H2O2 by an NIR-mediated "bursting-like" process to enhance its imaging and therapeutic functions. Black SnO2-x with abundant oxygen vacancies expedites effective separation of electron-hole pairs from energy-band structure and endows them with strong hyperthermia effect upon NIR laser irradiation. The generating toxic H2O2 with the assistance of GOx provides SnO2-x@AGP with the capacity of oxidative stress therapy. Ascended H2O2 can activate ABTS into ABTS•+. ABTS•+ not only possesses significant NIR absorption properties, but also disrupts intracellular glutathione to generate excessive reactive oxygen species for improved phototherapy, leading to more effective treatment together with oxidative stress therapy. Thus, SnO2-x@AGP with NIR-mediated and H2O2-activated performance presents tumor inhibition efficacy with minimized damage to normal tissues. These outstanding characteristics of SnO2-x@AGP bring an insight into the development of activatable nanoreactors for smart, precise, and non-invasive cancer theranostics.

An Efficient, Short Stimulus PANC-1 Cancer Cell Ablation and Electrothermal Therapy Driven by Hydrophobic Interactions

Promising results in clinical studies have been demonstrated by the utilization of electrothermal agents (ETAs) in cancer therapy. However, a difficulty arises from the balance between facilitating the degradation of ETAs, and at the same time, increasing the electrothermal performance/stability required for highly efficient treatment. In this study, we controlled the thermal signature of the MoS₂ by harnessing MoS₂ nanostructures with M13 phage (MNM) via the structural assembling (hydrophobic interaction) phenomena and developed a combined PANC-1 cancer cell-MNM alternating current (AC)-stimulus framework for cancer cell ablation and electrothermal therapy. A percentage decrease in the cell viability of ~23% was achieved, as well as a degradation time of 2 weeks; a stimulus length of 100 μs was also achieved. Molecular dynamics (MD) simulations revealed the assembling kinetics in integrated M13 phage-cancer cell protein systems and the structural origin of the hydrophobic interaction-enabled increase in thermal conduction. This study not only introduced an 'ideal' agent that avoided the limitations of ETAs but also provided a proof-of-concept application of MoS₂-based materials in efficacious cancer therapy.

Attachment of −tBu groups to aza-BODIPY core at 3,5-sites with ultra-large Stokes shift to enhance photothermal therapy through apoptosis mechanism

By the introduction of the −tBu groups into aza-BODIPY core, di-tert-butyl-substituted aza-BODIPYs at 3,5-sites (tBuazaBDPs) were prepared for the first time. Based on the X-ray analysis of CN-tBuazaBDP, this molecular structure is twisted. Near-infrared dye SMe-tBuazaBDP has the ultra-large Stokes shift (152 ​nm) in aza-BODIPY system, combining with the twisted intramolecular charge transfer and the free rotation of the −tBu groups at 3,5-sites. Although the barrier-free rotors of the distal −tBu groups in SMe-tBuazaBDP result in low fluorescence quantum yield, the photothermal conversion efficiency is markedly enhanced. SMe-tBuazaBDP nanoparticles with low power laser irradiation were proven to block cancer cell cycle, inhibit cancer cell proliferation, and induce cancer cell apoptosis in photothermal therapy (PTT). The strategy of “direct attachment of −tBu groups to aza-BODIPY core” gives a new design platform for a photothermal therapy agent.

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Di-tert-butyl-substituted aza-BODIPYs at 3,5-sites (tBuazaBDPs) were prepared for the first time.

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Near-infrared dye SMe-tBuazaBDP has the ultra-large Stokes shift (152 ​nm) in aza-BODIPY system.

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SMe-tBuazaBDP ​nanoparticles can photothermally induce apoptosis as a potential photothermal therapy agent.

Recyclable Endogenous H2 S Activation of Self-Assembled Nanoprobe with Controllable Biodegradation for Synergistically Enhanced Colon Cancer-Specific Therapy

Excessive production of hydrogen sulfide (H₂ S) plays a crucial role in the progress of colon cancer. Construction of tumor-specific H₂ S-activated smart nanoplatform with controllable biodegradation is of great significance for precise and sustainable treatment of colon cancer. Herein, an endogenous H₂ S triggered Co-doped polyoxometalate (POM-Co) cluster with self-adjustable size, controlled biodegradation, and sustainable cyclic depletion of H₂ S/glutathione (GSH) is designed for synergistic enhanced tumor-specific photothermal and chemodynamic therapy. The designed POM-Co nanocluster holds H₂ S responsive "turn-on" photothermal property in colon cancer via self-assembling to form large-sized POM-CoS, enhancing the accumulation at tumor sites. Furthermore, the formed POM-CoS can gradually biodegrade, resulting in release of Co²⁺ and Mo⁶⁺ for Co(II)-catalyzed •OH production and Russell mechanism-enabled ¹ O₂ generation with GSH consumption, respectively. More importantly, the degraded POM-CoS is reactivated by endogenous H₂ S for recyclable and sustainable consumption of H₂ S and GSH, resulting in tumor-specific photothermal/chemodynamic continuous therapy. Therefore, this study provides an opportunity of designing tumor microenvironment-driven nanoprobes with controllable biodegradation for precise and sustainable anti-tumor therapy.

Enhancing the therapeutic efficacy of nanoparticles for cancer treatment using versatile targeted strategies

Poor targeting of therapeutics leading to severe adverse effects on normal tissues is considered one of the obstacles in cancer therapy. To help overcome this, nanoscale drug delivery systems have provided an alternative avenue for improving the therapeutic potential of various agents and bioactive molecules through the enhanced permeability and retention (EPR) effect. Nanosystems with cancer-targeted ligands can achieve effective delivery to the tumor cells utilizing cell surface-specific receptors, the tumor vasculature and antigens with high accuracy and affinity. Additionally, stimuli-responsive nanoplatforms have also been considered as a promising and effective targeting strategy against tumors, as these nanoplatforms maintain their stealth feature under normal conditions, but upon homing in on cancerous lesions or their microenvironment, are responsive and release their cargoes. In this review, we comprehensively summarize the field of active targeting drug delivery systems and a number of stimuli-responsive release studies in the context of emerging nanoplatform development, and also discuss how this knowledge can contribute to further improvements in clinical practice.

All-In-One Second Near-Infrared Light-Responsive Drug Delivery System for Synergistic Chemo-Photothermal Therapy

Light-responsive nanocarrier-based drug delivery systems (NDDSs), due to their unique advantages such as safety, minimal cross-reaction, and spatiotemporal precision, have received wide attention. Notably, second near-infrared (NIR-II) light, which has a high penetration depth for manipulating NDDSs to release drugs, is in high demand. Herein, polyethylene glycol (PEG)-modified hollow Cu_xS nanoparticles (NPs) are developed as an all-in-one NIR-II light-responsive NDDS for synergistic chemo-photothermal therapy. First, Cu_xS-PEG NPs were prepared under mild conditions by using Cu₂O NPs as sacrificial templates. The morphology, photothermal effect, drug loading/releasing abilities, and synergistic chemo-photothermal therapy of Cu_xS-PEG NPs have been investigated. The Cu_xS-PEG NPs with hollow structures showed a high drug loading capacity (∼255 μg Dox per mg of Cu_xS NPs) and stimuli-responsive drug release triggered by NIR-II laser irradiation. The synergistic chemo-photothermal therapy based on the Dox/Cu_xS-PEG NPs showed 98.5% tumor elimination. Our study emphasizes the great potential of Cu_xS-PEG NPs as an all-in-one NIR-II light-responsive NDDS for applications in biomedicine.

Molecular imaging nanoprobes for theranostic applications

As a non-invasive imaging monitoring method, molecular imaging can provide the location and expression level of disease signature biomolecules in vivo, leading to early diagnosis of relevant diseases, improved treatment strategies, and accurate assessment of treating efficacy. In recent years, a variety of nanosized imaging probes have been developed and intensively investigated in fundamental/translational research and clinical practice. Meanwhile, as an interdisciplinary discipline, this field combines many subjects of chemistry, medicine, biology, radiology, and material science, etc. The successful molecular imaging not only requires advanced imaging equipment, but also the synthesis of efficient imaging probes. However, limited summary has been reported for recent advances of nanoprobes. In this paper, we summarized the recent progress of three common and main types of nanosized molecular imaging probes, including ultrasound (US) imaging nanoprobes, magnetic resonance imaging (MRI) nanoprobes, and computed tomography (CT) imaging nanoprobes. The applications of molecular imaging nanoprobes were discussed in details. Finally, we provided an outlook on the development of next generation molecular imaging nanoprobes.

Dual-sensitive fluorescent nanoprobes for detection of matrix metalloproteinases and low pH in a 3D tumor microenvironment

The overexpression of matrix metalloproteinases and low extracellular pH are two key physiological parameters involved in cancer initiation, progression, and metastasis. These have been the targets for several cancer detection and imaging modalities. Here, dual-sensitive nanoprobes have been fabricated from carbon nanoparticles decorated with a MMP-9 sensitive peptide sequence. Carbon nanoparticles are known for their intrinsic fluorescence properties and hence used as a pH-sensing moiety in the nanoprobes. In addition to this, selective-cleavage of the peptide sequence by MMP-9 results in the generation of a fluorescence signal due to separation of the quencher molecule from the fluorophore attached onto the MMP-9 sensitive peptide sequence, resulting in its detection. This protease-specific activation of the nanoprobes helps in precise tumor environment detection and imaging. The nanoprobes were thoroughly characterized for their chemical, physical and biological activities. The potential of these dual-sensitive nanoprobes to distinguish tumor-like microenvironments (low pH and elevated MMP-9 levels) from non-cancerous ones was evaluated in vitro in 2D cell culture as well as in 3D microscaffolds. The fluorescence microscopy images obtained in both in vitro systems revealed that low pH and high MMP-9 levels could be successfully visualised using these dual-sensitive nanoprobes. Therefore, these nanoprobes would find potential applications as a non-invasive imaging tool for visualising tumor margins in real-time.

Nanotechnology and Matrix Metalloproteinases in Cancer Diagnosis and Treatment

Cancer is still one of the leading causes of death worldwide. This great mortality is due to its late diagnosis when the disease is already at advanced stages. Although the efforts made to develop more effective treatments, around 90% of cancer deaths are due to metastasis that confers a systemic character to the disease. Likewise, matrix metalloproteinases (MMPs) are endopeptidases that participate in all the events of the metastatic process. MMPs’ augmented concentrations and an increased enzymatic activity have been considered bad prognosis markers of the disease. Therefore, synthetic inhibitors have been created to block MMPs’ enzymatic activity. However, they have been ineffective in addition to causing considerable side effects. On the other hand, nanotechnology offers the opportunity to formulate therapeutic agents that can act directly on a target cell, avoiding side effects and improving the diagnosis, follow-up, and treatment of cancer. The goal of the present review is to discuss novel nanotechnological strategies in which MMPs are used with theranostic purposes and as therapeutic targets to control cancer progression.

Neisseria sicca and Corynebacterium matruchotii inhibited oral squamous cell carcinomas by regulating genome stability

Periodontitis is a risk factor for the development of oral squamous cell carcinomas (OSCC). Both DNA damage response (DDR) and activation of inflammasomes induced by the microbiome might play important roles in the development of tumors, in relation to genome stability of tumor cells. Herein, we explored whether periodontitis negative-associated bacteria (Neisseria sicca and Corynebacterium matruchotii, namely called ‘PNB’), which were highly abundant in healthy populations, could inhibit OSCC by promoting genome stability. Firstly, a murine SCC-7 tumor-bearing model that colonized with PNB was designed and used in this study. Then, cyclin D1 was detected by immunohistochemistry. Levels of DDR, NLRP3 inflammasomes and pro-inflammatory cytokines in tumors were detected by RT-qPCR or Western blot. Immune cells in spleens were detected by immunohistochemistry or immunofluorescence. Finally, the anti-cancer activity of PNB was assessed in vitro using CCK-8 assays and flow cystometry. Compared with the control, PNB decreased tumor weights from 0.77 ± 0.26 g to 0.42 ± 0.15 g and downregulated the expression of Cyclin D1. PNB activated the DDR by up-regulating γ-H2AX, p-ATR, and p-CHK1. PNB activated NLRP3 inflammasome-mediated pyroptosis via increases of NLRP3, gasdermin D, and mRNA levels of apoptosis-associated speck-like protein, Caspase-1. PNB suppressed the inflammatory response by down-regulating mRNA levels of NF-κΒ and IL-6 in tumors as well as the populations of CD4+ T cells and CD206+ immune cells in spleens. PNB inhibited proliferation and promoted cell death of HSC-3 cells. In conclusion, Neisseria sicca and Corynebacterium matruchotii showed a ‘probiotic bacterial’ potential to inhibit OSCC by regulating genome stability.

Application of "smart" multifunctional nanoprobes in tumor diagnosis and treatment

Cancer is one of the major diseases that pose a threat to human health and life, especially because it is difficult to diagnose and cure, and recurs easily. In recent years, the development of nanotechnology has provided researchers with new tools for cancer treatment. In particular, nanoprobes that facilitate integrated diagnosis and treatment, high-resolution imaging, and accurate tumor targeting provide new avenues for the early detection and treatment of cancer. This review focuses on the preparations and applications of two kinds of "smart" multifunctional nanoprobes: "Off-On" nanoprobes and "Charge-Reversal" nanoprobes. This review also briefly discusses their mechanisms of action, as they could provide new ideas for the further development of this field.

A Transformable Amphiphilic and Block Polymer-Dendron Conjugate for Enhanced Tumor Penetration and Retention with Cellular Homeostasis Perturbation via Membrane Flow

Efficient penetration and retention of therapeutic agents in tumor tissues can be realized through rational design of drug delivery systems. Herein, a polymer-dendron conjugate, POEGMA-b-p(GFLG-Dendron-Ppa) (GFLG-DP), is presented, which allows a cathepsin-B-triggered stealthy-to-sticky structural transformation. The compositions and ratios are optimized through dissipative particle dynamics simulations. GFLG-DP displays tumor-specific transformation and the consequently released dendron-Ppa is found to effectively accumulate on the tumor cell membrane. The interaction between the dendron-Ppa and the tumor cell membrane results in intracellular and intercellular transport via membrane flow, thus achieving efficient deep penetration and prolonged retention of therapeutic agents in the solid tumor tissues. Meanwhile, the interaction of dendron-Ppa with the endoplasmic reticulum disrupts cell homeostasis, making tumor cells more vulnerable and susceptible to photodynamic therapy. This platform represents a versatile approach to augmenting the tumor therapeutic efficacy of a nanomedicine via manipulation of its interactions with tumor membrane systems.

Reasonable design of NIR AIEgens for fluorescence imaging and effective photothermal/photodynamic cancer therapy

The development of a multifunctional single molecule phototherapeutic agent with excellent fluorescence imaging, photothermal therapy and photodynamic therapy at the same time is still a challenging task, which mainly arises from the low absorbance of the molecule, and the complexity of energy dissipation and molecular design. Herein, four donor-acceptor (D-A) compounds were synthesized by linking triphenylamine (TPA), thiophene/thieno[3,2-b]thiophene and different cyano acceptor structures. In this design, we propose a molecular design strategy to redshift absorption and increase the molar extinction coefficient (ε) by enhancing electron-withdrawing acceptors and enlarging the π-conjugation plane unit. Due to the twisted structure of TPA, these compounds exhibit aggregation-induced emission (AIE) characteristics. Notably, these AIEgens have long emission wavelengths, excellent photostability, biocompatibility, photothermal stability and singlet oxygen (¹O₂) generation performance. Among them, the photothermal conversion efficiency of a compound (named TCF-SS-TPA NPs) can reach 84.5%. Cellular internalization and therapy showed that TCF-SS-TPA NPs have good biocompatibility, excellent cell bioimaging and cancer phototherapy capabilities in vitro. This study will stimulate the molecular design of multifunctional phototherapeutics to realize effective synergistic cancer therapy.

Cell membrane camouflaged biomimetic nanoparticles: Focusing on tumor theranostics

Nanoparticles (NPs) modified by cell membranes represent an emerging biomimetic platform that can mimic the innate biological functions resulting from the various cell membranes in biological systems. researchers focus on constructing the cell membrane camouflaged NPs using a wide variety of cells, such as red blood cell membranes (RBC), macrophages and cancer cells. Cell membrane camouflaged NPs (CMNPs) inherit the composition of cell membranes, including specific receptors, antigens, proteins, for target delivering to the tumor, escaping immune from clearance, and prolonging the blood circulation time, etc. Combining cell membrane-derived biological functions and the NP cores acted cargo carriers to encapsulate the imaging agents, CMNPs are widely developed to apply in tumor imaging techniques, including computed tomography (CT), magnetic resonance imaging (MRI), fluorescence imaging (FL) and photoacoustic imaging (PA). Herein, in this review, we systematically summarize the superior functions of various CMNPs in tumor imaging, especially highlighting the advanced applications in different imaging techniques, which is to provide the theoretical supports for the development of precise guided imaging and tumor treatment.

Biomarker-responsive Fluorescent Probes for In Vivo Imaging of Liver Injury

Liver injury-related diseases have aroused widespread concern due to its extreme unpredictability, acute onset, and severe consequences. Nowadays, the clinical prediction and assessment of liver injury mainly focus on histopathological and serological approaches, which undergoes a tedious process and sometimes requires invasive biopsy. Over the past decades, fluorescence imaging technique have emerged as a rising star for the diagnosis of diseases owing to its noninvasiveness, high fidelity and ease of operation. On regard to liver injury, the fluorescent probes have been delicately designed to response a variety of endogenous biomolecules to precisely offer comprehensive information about the lesion site. Herein, we make a brief summary and discussion about the design strategies and applications of the recently reported fluorescent biosensors responsive to a series of biomarkers involved in the liver injury. The potential prospects and remaining challenges are also discussed to promote the progression in this field.

Nanoparticle-assisted, image-guided laser interstitial thermal therapy for cancer treatment

Laser interstitial thermal therapy (LITT) guided by magnetic resonance imaging (MRI) is a new treatment option for patients with brain and non-central nervous system (non-CNS) tumors. MRI guidance allows for precise placement of optical fiber in the tumor, while MR thermometry provides real-time monitoring and assessment of thermal doses during the procedure. Despite promising clinical results, LITT complications relating to brain tumor procedures, such as hemorrhage, edema, seizures, and thermal injury to nearby healthy tissues, remain a significant concern. To address these complications, nanoparticles offer unique prospects for precise interstitial hyperthermia applications that increase heat transport within the tumor while reducing thermal impacts on neighboring healthy tissues. Furthermore, nanoparticles permit the co-delivery of therapeutic compounds that not only synergize with LITT, but can also improve overall effectiveness and safety. In addition, efficient heat-generating nanoparticles with unique optical properties can enhance LITT treatments through improved real-time imaging and thermal sensing. This review will focus on (1) types of inorganic and organic nanoparticles for LITT; (2) in vitro, in silico, and ex vivo studies that investigate nanoparticles' effect on light-tissue interactions; and (3) the role of nanoparticle formulations in advancing clinically relevant image-guided technologies for LITT. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Implantable Materials and Surgical Technologies > Nanoscale Tools and Techniques in Surgery.

Monocomponent Nanodots with Dichromatic Output Regulated by Synergistic Dual-Stimuli for Cervical Cancer Tissue Imaging and Photodynamic Tumor Therapy

Inflammation exists in the microenvironment of most, if not virtually all, tumors, which greatly exacerbates the difficulty of cancer treatment. Considering the superiority of activatable photosensitizers (PSs), a novel strategy of 'making friends with the enemy' for tumor treatment was proposed. In this strategy, the "enemy" refers to inflammatory cytokines and the tumor site is targeted by detecting the enemy. Upon detection, a dichromatic fluorescence signal is released and the PS is activated specifically by the inflammatory cytokines. In this study, a multifunctional PS (TPE-PTZ-Py) was rationally designed, which can be activated specifically under the synergistic action of hypochlorous acid (HClO) (one kind of inflammatory cytokines) and acid (one typical marker of tumor), and output a ratiometric fluorescence signal simultaneously. The sulfoxide analogue (TPE-PTZO-PyH) as the response product effectively produced ¹O₂ (1.8-fold higher than that obtained with Rose Bengal) and showed high phototoxicity (IC₅₀ < 7.6 μM). More importantly, imaging analyses confirmed that TPE-PTZ-Py could be activated in human cervical cancer tissue. To date, several phenothiazine (PTZ)-based fluorescent probes have been developed for the selective sensing and imaging of HClO in subcellular organelles; however, this is the first phenothiazine-based nanodrug designed for the treatment of inflammation-associated tumors with a few side effects.

Se-modified gold nanorods for enhancing the efficiency of photothermal therapy: avoiding the off-target problem induced by biothiols

Tumor-targeting gold nanorods (AuNRs) assembled through Au-S bonds have been widely used for photothermal therapy (PTT) via intravenous injection. However, with extended in vivo circulation times, biothiols can replace some S-modified targeting ligands on the surface of the AuNRs, which lowers their targeting efficacy towards cancer cells, resulting in a non-ideal PTT effect. To address this problem, herein, we utilized Se-modified AuNRs to establish a dual functional nanoprobe (Casp-RGD-Se-AuNRs) for improving the therapeutic effect and real-time monitoring of Caspase-9 levels to indicate the degree of cell apoptosis. The experiments demonstrated that the Casp-RGD-Se-AuNRs are better at avoiding interference from biothiols than the S-modified nanoprobe (Casp-RGD-S-AuNRs) for extended blood-circulation times after intravenous injection, significantly improving the PTT efficacy via more effectively targeting cancer cells. Simultaneously, the change of Caspase-9 levels visually shows the degree of apoptosis. Moreover, an in vivo study showed that, compared with the S-modified nanoprobe, the Se-modified nanoprobe exhibits a higher delivery efficiency to the tumor region after intravenous injection (accumulation in the tumor increased by 87%) and a better anticancer efficacy under NIR light irradiation (the tumor inhibition rate increased 6-fold). This work provides a valuable strategy to overcome the off-target problem, and new ideas for avoiding interference by biomolecules during blood circulation.

Emerging strategies in developing multifunctional nanomaterials for cancer nanotheranostics

Cancer involves a collection of diseases with a common trait - dysregulation in cell proliferation. At present, traditional therapeutic strategies against cancer have limitations in tackling various tumors in clinical settings. These include chemotherapeutic resistance and the inability to overcome intrinsic physiological barriers to drug delivery. Nanomaterials have presented promising strategies for tumor treatment in recent years. Nanotheranostics combine therapeutic and bioimaging functionalities at the single nanoparticle level and have experienced tremendous growth over the past few years. This review highlights recent developments of advanced nanomaterials and nanotheranostics in three main directions: stimulus-responsive nanomaterials, nanocarriers targeting the tumor microenvironment, and emerging nanomaterials that integrate with phototherapies and immunotherapies. We also discuss the cytotoxicity and outlook of next-generation nanomaterials towards clinical implementation.