Hybrid Nanoplatform: Enabling a Precise Antitumor Strategy via Dual-Modal Imaging-Guided Photodynamic/Chemo-/Immunosynergistic Therapy

Targeting Hydrogel for Intelligent Recognition and Spatiotemporal Control in Cell-Based Therapeutics

Smart drug platforms based on spatiotemporally controlled release and integration of tumor imaging are expected to overcome the inefficiency and uncertainty of traditional theranostic modes. In this study, a composite consisting of a thermosensitive hydrogel (polyvinyl alcohol-carboxylic acid hydrogel (PCF)) and a multifunctional nanoparticle (Fe3O4@Au/Mn(Zn)-4-carboxyphenyl porphyrin/polydopamine (FAMxP)) is developed to combine tumor immunogenic cell death (ICD)/immune checkpoint blockade (ICB) therapy under the guidance of magnetic resonance imaging (MRI) and fluorescence imaging (FI). It can not only further recognize the target cells through the folate receptor of tumor cells, but also produce thermal dissolution after exposure to near-infrared light to slowly release FAMxP in situ, thereby prolonging the treatment time and avoiding tumor recurrence. As FAMxP entered the tumor cells, it released FAMx in a pH-dependent manner. Chemodynamic, photothermal and photodynamic therapy can cause significant ICD in cancer cells. ICB can thus be further enhanced by injecting anti-programmed cell death ligand 1, improving the effectiveness of tumor treatment. The developed PCF-FAMxP composite hydrogel may represent an updated drug design approach with simple compositions for cooperative MRI/FI-guided targeted therapeutic pathways for tumors.

Dismantlable Coronated Nanoparticles for Coupling the Induction and Perception of Immunogenic Cell Death

Therapy-induced immunogenic cell death (ICD) can initiate both innate and adaptive immune responses for amplified anti-tumor efficacy. However, dying cell-released ICD signals are prone to being sequestered by the TIM-3 receptors on dendritic cell (DC) surfaces, preventing immune surveillance. Herein, dismantlable coronated nanoparticles (NPs) are fabricated as a type of spatiotemporally controlled nanocarriers for coupling tumor cell-mediated ICD induction to DC-mediated immune sensing. These NPs are loaded with an ICD inducer, mitoxantrone (MTO), and wrapped by a redox-labile anti-TIM-3 (αTIM-3) antibody corona, forming a separable core-shell structure. The antibody corona disintegrates under high levels of extracellular reactive oxygen species in the tumor microenvironment, exposing the MTO-loaded NP core for ICD induction and releasing functional αTIM-3 molecules for DC sensitization. Systemic administration of the coronated NPs augments DC maturation, promotes cytotoxic T cell recruitment, enhances tumor susceptibility to immune checkpoint blockade, and prevents the side effects of MTO. This study develops a promising nanoplatform to unleash the potential of host immunity in cancer therapy.

TME-Triggered Degradable Phototheranostic Nanoplatform for NIR-II Fluorescence Bioimaging-Guided Phototherapies and Immune Activation

The low therapeutic efficacy and potential long-term toxicity of antitumor treatments seriously limit the clinical application of phototherapies. Herein, we develop a degradable phototheranostic nanoplatform for NIR-II fluorescence bioimaging-guided synergistic photothermal (PTT) and photodynamic therapies (PDT) and immune activation to inhibit tumor growth. The phototheranostic nanoplatform (CX@PSS) consists of multidisulfide-containing polyurethane loaded with a photosensitizer CX, which can be specifically degraded in the GSH overexpressed tumor microenvironment (TME) and exhibits good NIR-II fluorescence, photodynamic, and photothermal properties. Under 808 nm light irradiation, CX@PSS exhibits efficient photothermal conversion and ROS generation, which further induces immunogenic cell death (ICD), releasing tumor-associated antigens and activating the immune response. In vitro and in vivo studies confirm the potential of CX@PSS in NIR II FL imaging-guided tumor treatments by synergistic PTT, PDT, and immune activation. This work is expected to provide a new pathway for clinical applications of imaging-guided tumor diagnosis and treatments.

Disrupting redox homeostasis for tumor therapy based on PDT/chemo/ferroptosis therapeutic hybrid liposomes

Synergistic photodynamic therapy (PDT) with other therapeutic modalities can enhance the therapeutic efficacy of tumor treatment and reduce the adverse effects associated with drug leakage and off-target accumulation. However, shaping combined strategies for synergistic therapy remains challenging. Herein, we developed versatile hybrid liposomes self-assembled from Ce6-lipid conjugates and loaded with the chemo drug doxorubicin (DOX) and ferroptosis inducer Fe3O4 nanoparticles for synergistic PDT/chemo/ferroptosis therapy. Abundant ROS are generated by PDT upon 650 nm light irradiation, Fe3O4-mediated Fenton reaction, and DOX-induced apoptosis. Furthermore, amplifying oxidative stress in cancer cells to disrupt cellular redox homeostasis could accelerate tumor cell death through oxidative damage to lipids, proteins, and DNA. Overall, this work highlights liposome-based therapeutic nanoformulations, thus offering a breakthrough redox homeostasis-based synergistic PDT/chemo/ferroptosis therapy for lung cancer.

Multi-target responsive nanoprobe with cellular-level accuracy for spatiotemporally selective photodynamic therapy

Photodynamic therapy is known for its non-invasiveness to significantly reduce undesired side effects on patients. However, the infiltration and invasiveness of tumor growth are still beyond the specificity of traditional light-controlled photodynamic therapy (PDT), which lacks cellular-level accuracy to tumor cells, possibly leading to "off-target" damage to healthy tissues such as the skin or immune cells infiltrated. Here, upconversion nanoparticles (UCNPs) were co-encapsulated with manganese dioxide (MnO2) by amphiphilic polymers poly(styrene-co-methyl acrylate) (PSMA) and further coated with photosensitizer (riboflavin)-loaded mesoporous silica (C@S/V). The C@S/V nanoprobes exhibited shielded upconversion luminescence in normal conditions (pH 7.4, no hydroperoxide (H2O2)) under 980-nm irradiation and thus minimal reactive oxygen production from riboflavin. However, the excess H2O2 (1 mM) and acidic environment (pH 5.5) could decompose the MnO2 within the C@S/V, resulting in remarkable enhancement of upconversion luminescence and a favorable hypoxia-relieving condition for PDT, providing a spatiotemporal signal for therapy initiation. The C@S/V nanoprobes were applied to the co-culture of normal cells (HEK293) and pancreatic cancer cells (Panc02) and performed a selective killing on Panc02 under the 980-nm irradiation. By using the "double-safety" strategy, a responsive C@S/V nanoprobe was designed by the selective activation of acidic and H2O2-rich conditions and 980-nm irradiation for spatiotemporally selective photodynamic therapy with cellular-level accuracy.

Four Ounces Can Move a Thousand Pounds: The Enormous Value of Nanomaterials in Tumor Immunotherapy

The application of nanomaterials in healthcare has emerged as a promising strategy due to their unique structural diversity, surface properties, and compositional diversity. In particular, nanomaterials have found a significant role in improving drug delivery and inhibiting the growth and metastasis of tumor cells. Moreover, recent studies have highlighted their potential in modulating the tumor microenvironment (TME) and enhancing the activity of immune cells to improve tumor therapy efficacy. Various types of nanomaterials are currently utilized as drug carriers, immunosuppressants, immune activators, immunoassay reagents, and more for tumor immunotherapy. Necessarily, nanomaterials used for tumor immunotherapy can be grouped into two categories: organic and inorganic nanomaterials. Though both have shown the ability to achieve the purpose of tumor immunotherapy, their composition and structural properties result in differences in their mechanisms and modes of action. Organic nanomaterials can be further divided into organic polymers, cell membranes, nanoemulsion-modified, and hydrogel forms. At the same time, inorganic nanomaterials can be broadly classified as nonmetallic and metallic nanomaterials. The current work aims to explore the mechanisms of action of these different types of nanomaterials and their prospects for promoting tumor immunotherapy.

Pre-activated nanoparticles with persistent luminescence for deep tumor photodynamic therapy in gallbladder cancer

Phototherapy of deep tumors still suffers from many obstacles, such as limited near-infrared (NIR) tissue penetration depth and low accumulation efficiency within the target sites. Herein, stimuli-sensitive tumor-targeted photodynamic nanoparticles (STPNs) with persistent luminescence for the treatment of deep tumors are reported. Purpurin 18 (Pu18), a porphyrin derivative, is utilized as a photosensitizer to produce persistent luminescence in STPNs, while lanthanide-doped upconversion nanoparticles (UCNPs) exhibit bioimaging properties and possess high photostability that can enhance photosensitizer efficacy. STPNs are initially stimulated by NIR irradiation before intravenous administration and accumulate at the tumor site to enter the cells through the HER2 receptor. Due to Pu18 afterglow luminescence properties, STPNs can continuously generate ROS to inhibit NFκB nuclear translocation, leading to tumor cell apoptosis. Moreover, STPNs can be used for diagnostic purposes through MRI and intraoperative NIR navigation. STPNs exceptional antitumor properties combined the advantages of UCNPs and persistent luminescence, representing a promising phototherapeutic strategy for deep tumors.

Multifunctional Nanotheranostics for Dual-Modal Imaging-Guided Precision Therapy of Nasopharyngeal Carcinoma

Currently, the low survival rate and poor prognosis of patients with nasopharyngeal carcinoma are ascribed to the lack of early and accurate diagnosis and resistance to radiotherapy. In parallel, the integration of imaging-guided diagnosis and precise treatment has gained much attention in the field of theranostic nanotechnology. However, constructing dual-modal imaging-guided nanotheranostics with desired imaging performance as well as great biocompatibility remains challenging. Therefore, we developed a simple but multifunctional nanotheranostic GdCPP for the early and accurate diagnosis and efficient treatment of nasopharyngeal carcinoma (NPC), which combined fluorescence imaging and magnetic resonance imaging (MRI) onto a single nanoplatform for imaging-guided subsequent photodynamic therapy (PDT). GdCPP had an appropriate particle size (81.93 ± 0.69 nm) and was highly stable, resulting in sufficient tumor accumulation, which along with massive reactive oxygen species (ROS) generation upon irradiation further significantly killed tumor cells. Moreover, GdCPP owned much stronger r1 relaxivity (9.396 mM-1 s-1) compared to clinically used Gd-DTPA (5.034 mM-1 s-1) and exhibited better T1WI MRI performance. Under dual-modal imaging-guided PDT, GdCPP achieved efficient therapeutic outcomes without causing any noticeable tissue damage. The results of in vitro and in vivo studies indicated that GdCPP may be a suitable candidate for dual-modal imaging-guided precision tumor therapy.

Recent advances of lanthanide nanomaterials in Tumor NIR fluorescence detection and treatment

Lanthanide nanomaterials have garnered significant attention from researchers among the main near-infrared (NIR) fluorescent nanomaterials due to their excellent chemical and fluorescence stability, narrow emission band, adjustable luminescence color, and long lifetime. In recent years, with the preparation, functional modification, and fluorescence improvement of lanthanide materials, great progress has been made in their application in the biomedical field. This review focuses on the latest progress of lanthanide nanomaterials in tumor diagnosis and treatment, as well as the interaction mechanism between fluorescence and biological tissues. We introduce a set of efficient strategies for improving the fluorescence properties of lanthanide nanomaterials and discuss some representative in-depth research work in detail, showcasing their superiority in early detection of ultra-small tumors, phototherapy, and real-time guidance for surgical resection. However, lanthanide nanomaterials have only realized a portion of their potential in tumor applications so far. Therefore, we discuss promising methods for further improving the performance of lanthanide nanomaterials and their future development directions.

Cancer Immunotherapy Elicited by Immunogenic Cell Death Based on Smart Nanomaterials

Cancer immunotherapy has been a revolutionary cancer treatment modality because it can not only eliminate primary tumors but also prevent metastases and recurrent tumors. Immunogenic cell death (ICD) induced by various treatment modalities, including chemotherapy, phototherapy, and radiotherapy, converts dead cancer cells into therapeutic vaccines, eliciting a systemic antigen-specific antitumor. However, the outcome effect of cancer immunotherapy induced by ICD has been limited due to the low accumulation efficiency of ICD inducers in the tumor site and concomitant damage to normal tissues. The boom in smart nanomaterials is conducive to overcoming these hurdles owing to their virtues of good stability, targeted lesion site, high bioavailability, on-demand release, and good biocompatibility. Herein, the design of targeted nanomaterials, various ICD inducers, and the applications of nanomaterials responsive to different stimuli, including pH, enzymes, reactive oxygen species, or dual responses are summarized. Furthermore, the prospect and challenges are briefly outlined to provide reference and inspiration for designing novel smart nanomaterials for immunotherapy induced by ICD.

Superenhancement Photon Upconversion Nanoparticles for Photoactivated Nanocryometer

Highly doped lanthanide luminescent nanoparticles exhibit unique optical properties, providing exciting opportunities for many ground-breaking applications, such as super-resolution microscopy, deep-tissue bioimaging, confidentiality, and anticounterfeiting. However, the concentration-quenching effect compromises their luminescence efficiency/brightness, hindering their wide range of applications. Herein, we developed a low-temperature suppression cross-relaxation strategy, which drastically enhanced upconversion luminescence (up to 2150-fold of green emission) in Er³⁺-rich nanosystems. The cryogenic field opens the energy transport channel of Er³⁺ multiphoton upconversion by further suppressing phonon-assisted cross-relaxation. Our results provide direct evidence for understanding the energy loss mechanism of photon upconversion, deepening a fundamental understanding of the upconversion process in highly doped nanosystems. Furthermore, it also suggests the potential applications of upconversion nanoparticles for extreme ambient-temperature detection and anticounterfeiting.

Nanoscale metal-organic framework delivers rapamycin to induce tissue immunogenic cell death and potentiates cancer immunotherapy

Rapamycin has great potential in the antitumor application, but its therapeutic effect is seriously affected by poor water solubility, targeting ability, and low bioavailability. Here, we constructed a novel composite nanomaterial with PCN-224 as a drug carrier and loaded rapamycin, named R@BP@HA. The nanoplate not only improves targeting, but also synergizes rapamycin with PCN-224 to effectively promote tumor cell apoptosis, which subsequently causes immunogenic cell death (ICD), and shows strong therapeutic effect in 4T1 breast cancer model. The treatment effect depends on three main points:(i)Proapoptotic effect of rapamycin on tumor cells;(ii)ROS production by PCN-224-mediated photodynamic therapy;(iii)ICD induced DC maturation, increased immune response and promoted T cell proliferation and differentiation. This nanoplate offers potential antitumor efficacy in combination with chemotherapy, photodynamic therapy, and immunotherapy.

Vaccine-like nanomedicine for cancer immunotherapy

The successful clinical application of immune checkpoint blockade (ICB) and chimeric antigen receptor T cells (CAR-T) therapeutics has attracted extensive attention to immunotherapy, however, their drawbacks such as limited specificity, persistence and toxicity haven't met the high expectations on efficient cancer treatments. Therapeutic cancer vaccines which instruct the immune system to capture tumor specific antigens, generate long-term immune memory and specifically eliminate cancer cells gradually become the most promising strategies to eradicate tumor. However, the disadvantages of some existing vaccines such as weak immunogenicity and in vivo instability have restricted their development. Nanotechnology has been recently incorporated into vaccine fabrication and exhibited promising results for cancer immunotherapy. Nanoparticles promote the stability of vaccines, as well as enhance antigen recognition and presentation owing to their nanometer size which promotes internalization of antigens by phagocytic cells. The surface modification with targeting units further permits the delivery of vaccines to specific cells. Meanwhile, nanocarriers with adjuvant effect can improve the efficacy of vaccines. In addition to classic vaccines composed of antigens and adjuvants, the nanoparticle-mediated chemotherapy, radiotherapy and certain other therapeutics could induce the release of tumor antigens in situ, which therefore effectively simulate antitumor immune responses. Such vaccine-like nanomedicine not only kills primary tumors, but also prevents tumor recurrence and helps eliminate metastatic tumors. Herein, we introduce recent developments in nanoparticle-based delivery systems for antigen delivery and in situ antitumor vaccination. We will also discuss the remaining opportunities and challenges of nanovaccine in clinical translation towards cancer treatment.

Carrier-Free ATP-Activated Nanoparticles for Combined Photodynamic Therapy and Chemotherapy under Near-Infrared Light

The combination of photodynamic therapy (PDT) and chemotherapy (chemo-photodynamic therapy) for enhancing cancer therapeutic efficiency has attracted tremendous attention in the recent years. However, limitations, such as low local concentration, non-suitable treatment light source, and uncontrollable release of therapeutic agents, result in reduced combined treatment efficacy. This study considered adenosine triphosphate (ATP), which is highly upregulated in tumor cells, as a biomarker and developed ingenious ATP-activated nanoparticles (CDNPs) that are directly self-assembled from near-infrared photosensitizer (Cy-I) and amphiphilic Cd(II) complex (DPA-Cd). After selective entry into tumor cells, the positively charged CDNPs would escape from lysosomes and be disintegrated by the high ATP concentration in the cytoplasm. The released Cy-I is capable of producing single oxygen (¹ O₂ ) for PDT with 808 nm irradiation and DPA-Cd can concurrently function for chemotherapy. Irradiation with 808 nm light can lead to tumor ablation in tumor-bearing mice after intravenous injection of CDNPs. This carrier-free nanoparticle offers a new platform for chemo-photodynamic therapy.

Bright Tm3+-based downshifting luminescence nanoprobe operating around 1800 nm for NIR-IIb and c bioimaging

Fluorescence bioimaging based on rare-earth-doped nanocrystals (RENCs) in the shortwave infrared (SWIR, 1000-3000 nm) region has aroused intense interest due to deeper penetration depth and clarity. However, their downshifting emission rarely shows sufficient brightness beyond 1600 nm, especially in NIR-IIc. Here, we present a class of thulium (Tm) self-sensitized RENC fluorescence probes that exhibit bright downshifting luminescence at 1600-2100 nm (NIR-IIb/c) for in vivo bioimaging. An inert shell coating minimizes surface quenching and combines strong cross-relaxation, allowing LiTmF₄@LiYF₄ NPs to emit these intense downshifting emissions by absorbing NIR photons at 800 nm (large Stokes shift ~1000 nm with a absolute quantum yield of ~14.16%) or 1208 nm (NIR-II_in and NIR-II_out). Furthermore, doping with Er³⁺ for energy trapping achieves four-wavelength NIR irradiation and bright NIR-IIb/c emission. Our results show that Tm-based NPs, as NIR-IIb/c nanoprobes with high signal-to-background ratio and clarity, open new opportunities for future applications and translation into diverse fields.

Where Is Nano Today and Where Is It Headed? A Review of Nanomedicine and the Dilemma of Nanotoxicology

Worldwide nanotechnology development and application have fueled many scientific advances, but technophilic expectations and technophobic demands must be counterbalanced in parallel. Some of the burning issues today are the following: (1) Where is nano today? (2) How good are the communication and investment networks between academia/research and governments? (3) Is there any spotlight application for nanotechnology? Nanomedicine is a particular arm of nanotechnology within the healthcare landscape, focused on diagnosis, treatment, and monitoring of emerging (such as coronavirus disease 2019, COVID-19) and contemporary (including diabetes, cardiovascular diseases, neurodegenerative disorders, and cancer) diseases. However, it may only represent the bright side of the coin. In fact, in the recent past, the concept of nanotoxicology has emerged to address the dark shadows of nanomedicine. The nanomedicine field requires more nanotoxicological studies to identify undesirable effects and guarantee safety. Here, we provide an overall perspective on nanomedicine and nanotoxicology as central pieces of the giant puzzle of nanotechnology. First, the impact of nanotechnology on education and research is highlighted, followed by market trends and scientific output tendencies. In the next section, the nanomedicine and nanotoxicology dilemma is addressed through the interplay of in silico, in vitro, and in vivo models with the support of omics and microfluidic approaches. Lastly, a reflection on the regulatory issues and clinical trials is provided. Finally, some conclusions and future perspectives are proposed for a clearer and safer translation of nanomedicines from the bench to the bedside.