Metal-organic framework-mediated multifunctional nanoparticles for combined chemo-photothermal therapy and enhanced immunotherapy against colorectal cancer

Potentiating dual-directional immunometabolic regulation with nanomedicine to enhance anti-tumor immunotherapy following incomplete photothermal ablation

Photothermal therapy (PTT) is a promising cancer treatment method due to its ability to induce tumor-specific T cell responses and enhance therapeutic outcomes. However, incomplete PTT can leave residual tumors that often lead to new metastases and decreased patient survival in clinical scenarios. This is primarily due to the release of ATP, a damage-associated molecular pattern that quickly transforms into the immunosuppressive metabolite adenosine by CD39, prevalent in the tumor microenvironment, thus promoting tumor immune evasion. This study presents a photothermal nanomedicine fabricated by electrostatic adsorption among the Fe-doped polydiaminopyridine (Fe-PDAP), indocyanine green (ICG), and CD39 inhibitor sodium polyoxotungstate (POM-1). The constructed Fe-PDAP@ICG@POM-1 (FIP) can induce tumor PTT and immunogenic cell death when exposed to a near-infrared laser. Significantly, it can inhibit the ATP-adenosine pathway by dual-directional immunometabolic regulation, resulting in increased ATP levels and decreased adenosine synthesis, which ultimately reverses the immunosuppressive microenvironment and increases the susceptibility of immune checkpoint blockade (aPD-1) therapy. With the aid of aPD-1, the dual-directional immunometabolic regulation strategy mediated by FIP can effectively suppress/eradicate primary and distant tumors and evoke long-term solid immunological memory. This study presents an immunometabolic control strategy to offer a salvage option for treating residual tumors following incomplete PTT.

Repurposing indocyanine green: exploring the potential of an old drug in modern medicine

The repurposing of existing drugs, referred to as theranostics, has made profound impacts on precision medicine. Indocyanine green (ICG), a well-established and clinical dye, has continued to be a star agent, described as a multifunctional molecule with concurrent photo- or sono-sensitiveness capabilities and co-delivery accessibility, showing remarkable potential in the area of unimodal or multimodal imaging-guided therapy of various diseases, leading to the extensive consideration of immediate clinical translations. In this review, we strive to bring the understanding of repurposing performance assessment for ICG into practice by clarifying the relationships between its features and applicability. Specifically, we address the obstacles encountered in the process of developing an ICG repurposing strategy, as well as the noteworthy advancements made in the field of ICG repurposing. We also go into detail about the structure-function correlations of drugs containing ICG and how different structural groups significantly affect the physicochemical properties.

Alginate di-aldehyde-modified metal-organic framework nanocarriers as delivery platform and adjuvant in inactivated pseudorabies vaccination

Pseudorabies virus (PRV) is a highly contagious viral disease, which leads to severe financial losses in the breeding industry worldwide. Presently, PRV is mainly controlled using live attenuated and inactivated vaccines. However, these vaccines have an innate tendency to lose their structural conformation upon exposure to environmental and chemical stressors and cannot provide full protection against the emerging prevalent PRV variants. In this work, first, we synthesized aminated ZIF-7/8 nanoparticles (NPs), and then chemical bond-coated alginate dialdehyde (ADA, a type of dioxide alginate saccharide) on their surface via Schiff base reaction to obtain ZIF-7/8-ADA NPs. The as-fabricated ZIF-7/8-ADA NPs exhibited high stability, monodispersity and a high loading ratio of antigen. Furthermore, the ZIF-7/8-ADA NPs showed good biocompatibility in vitro and in vivo. Using ZIF-7/8-ADA NPs as an adjuvant and inactivated PRV as a model antigen, we constructed a PR vaccine through a simple mixture. The immunity studies indicated that ZIF-7/8-ADA induced an enhancement in the Th1/Th2 immune response, which was superior to that of the commercial ISA201, alum adjuvant and ZIF-7/8. Due to the pH-sensitive release of the antigen in lysosomes, the as-prepared PR vaccine subsequently accelerated the antigen presentation and improved the immune responses in vitro and in vivo. The results of PRV challenge using mice as the model demonstrated that ZIF-7/8-ADA achieved the same preventive effect as the commercial ISA201 and was much better than the alum adjuvant, and thus can serve as a promising delivery system and adjuvant to enhance humoral and cellular responses against PRV infection.

Homologous-magnetic dual-targeted metal-organic framework to improve the Anti-hepatocellular carcinoma efficacy of PD-1 inhibitor

The insufficient abundance and weak activity of tumour-infiltrating lymphocytes (TILs) are two important reasons for the poor efficacy of PD-1 inhibitors in hepatocellular carcinoma (HCC) treatment. The combined administration of tanshinone IIA (TSA) and astragaloside IV (As) can up-regulate the abundance and activity of TILs by normalising tumour blood vessels and reducing the levels of immunosuppressive factors respectively. For enhancing the efficacy of PD-1 antibody, a magnetic metal-organic framework (MOF) with a homologous tumour cell membrane (Hm) coating (Hm@TSA/As-MOF) is established to co-deliver TSA&As into the HCC microenvironment. Hm@TSA/As-MOF is a spherical nanoparticle and has a high total drug-loading capacity of 16.13 wt%. The Hm coating and magnetic responsiveness of Hm@TSA/As-MOF provide a homologous-magnetic dual-targeting, which enable Hm@TSA/As-MOF to counteract the interference posed by ascites tumour cells and enhance the precision of targeting solid tumours. Hm coating also enable Hm@TSA/As-MOF to evade immune clearance by macrophages. The release of TSA&As from Hm@TSA/As-MOF can be accelerated by HCC microenvironment, thereby up-regulating the abundance and activity of TILs to synergistic PD-1 antibody against HCC. This study presents a nanoplatform to improve the efficacy of PD-1 inhibitors in HCC, providing a novel approach for anti-tumour immunotherapy in clinical practice.

MRI-guided photothermal/photodynamic immune activation combined with PD-1 inhibitor for the multimodal combination therapy of melanoma and metastases

Non-invasive image-guided precise photothermal/photodynamic therapy (PTT/PDT) has been proven to be an effective local treatment modality but incompetent against metastases. Hence, the combination of local PTT/PDT and systemic immunotherapy would be a promising strategy for tumor eradication. Herein, a magnetic resonance imaging (MRI)-visualized PTT/PDT agent (SIDP NMs) was constructed, and the efficacy of its multimodal combination with a programmed cell death 1 (PD-1) inhibitor in the treatment of melanoma and metastases was studied. Due to the hydrophobic encapsulation of indocyanine green within the micellar core, SIDP NMs exhibited excellent photothermal/photodynamic properties and stability under an 808 nm near-infrared laser. In vitro cell experiments showed that SIDP NMs had a good killing effect. After incubating with B16-F10 cells for 24 h and irradiating with an 808-nm laser for 10 min, cell viability decreased significantly. Magnetic resonance imaging experiments in melanoma-bearing mice have shown that the dynamic distribution of SIDP NMs in tumor tissue could be monitored by T2WI and T2-MAP non-invasively due to the presence of superparamagnetic iron oxide nanocrystal in SIDP NMs. When the 808 nm laser was irradiated at the maximum focusing time point shown by MRI, the temperature of the tumor area rapidly increased from 32°C to 60.7°C in 5 min. In mouse melanoma ablation and distant tumor immunotherapy studies, SIDP NMs provided excellent MRI-guided PTT/PDT results and, when combined with PD-1 inhibitor, have great potential to cure primary tumors and eradicate metastases.

Biomedical application of metal-organic frameworks (MOFs) in cancer therapy: Stimuli-responsive and biomimetic nanocomposites in targeted delivery, phototherapy and diagnosis

The nanotechnology is an interdisciplinary field that has become a hot topic in cancer therapy. Metal-organic frameworks (MOFs) are porous materials and hybrid composites consisted of organic linkers and metal cations. Despite the wide application of MOFs in other fields, the potential of MOFs for purpose of cancer therapy has been revealed by the recent studies. High surface area and porosity, significant drug loading and encapsulation efficiency are among the benefits of using MOFs in drug delivery. MOFs can deliver genes/drugs with selective targeting of tumor cells that can be achieved through functionalization with ligands. The photosensitizers and photo-responsive nanostructures including carbon dots and gold nanoparticles can be loaded in/on MOFs to cause phototherapy-mediated tumor ablation. The immunogenic cell death induction and increased infiltration of cytotoxic CD8+ and CD4+ T cells can be accelerated by MOF platforms in providing immunotherapy of tumor cells. The stimuli-responsive MOF platforms responsive to pH, redox, enzyme and ion can accelerate release of therapeutics in tumor site. Moreover, MOF nanocomposites can be modified ligands and green polymers to improve their selectivity and biocompatibility for cancer therapy. The application of MOFs for the detection of cancer-related biomarkers can participate in the early diagnosis of patients.

Research progress on antibacterial applications of metal-organic frameworks and their biomacromolecule composites

With the extensive use of antibiotics, resulting in increasingly serious problems of bacterial resistance, antimicrobial therapy has become a global concern. Metal-organic frameworks (MOFs) are low-density porous coordination materials composed of metal ions and organic ligands, which can form composite materials with biomacromolecules such as proteins and polysaccharides. In recent years, MOFs and their derivatives have been widely used in the antibacterial field as efficient antibacterial agents. This review offers a detailed summary of the antibacterial applications of MOFs and their composites, and the different synthesis methods and antibacterial mechanisms of MOFs and MOF-based composites are briefly introduced. Finally, the challenges and prospects of MOFs-based antibacterial materials in the rapidly developing medical field were briefly discussed. We hope this review will provide new strategies for the medical application of MOFs-based antibacterial materials.

Research progress of organic photothermal agents delivery and synergistic therapy systems

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

Biological landscape and nanostructural view in development and reversal of oxaliplatin resistance in colorectal cancer

The treatment of cancer patients has been mainly followed using chemotherapy and it is a gold standard in improving prognosis and survival rate of patients. Oxaliplatin (OXA) is a third-platinum anti-cancer agent that reduces DNA synthesis in cancer cells to interfere with their growth and cell cycle progression. In spite of promising results of using OXA in cancer chemotherapy, the process of drug resistance has made some challenges. OXA is commonly applied in treatment of colorectal cancer (CRC) as a malignancy of gastrointestinal tract and when CRC cells increase their proliferation and metastasis, they can obtain resistance to OXA chemotherapy. A number of molecular factors such as CHK2, SIRT1, c-Myc, LATS2 and FOXC1 have been considered as regulators of OXA response in CRC cells. The non-coding RNAs are able to function as master regulator of other molecular pathways in modulating OXA resistance. There is a close association between molecular mechanisms such as apoptosis, autophagy, glycolysis and EMT with OXA resistance, so that apoptosis inhibition, pro-survival autophagy induction and stimulation of EMT and glycolysis can induce OXA resistance in CRC cells. A number of anti-tumor compounds including astragaloside IV, resveratrol and nobiletin are able to enhance OXA sensitivity in CRC cells. Nanoparticles for increasing potential of OXA in CRC suppression and reversing OXA resistance have been employed in cancer chemotherapy. These subjects are covered in this review article to shed light on molecular factors resulting in OXA resistance.

Tumor-activated targetable photothermal chemotherapy using IR780/zoledronic acid-containing hybrid polymeric nanoassemblies with folate modification to treat aggressive breast cancer

To effectively treat aggressive breast cancer by tumor-activated targetable photothermal chemotherapy, in this work, folate (FA)-modified hybrid polymeric nanoassemblies (HPNs) with a poly(ethylene glycol) (PEG)-detachable capability are developed as vehicles for tumor-targeted co-delivery of IR780, a lipophilic photothermal reagent, and zoledronic acid (ZA), a hydrophilic chemotherapy drug. Through hydrophobic interaction-induced co-assembly, IR780 molecules and ZA/poly(ethylenimine) (PEI) complexes were co-encapsulated into a poly(lactic-co-glycolic acid) (PLGA)-rich core stabilized by the amphiphilic FA-modified D-α-tocopheryl poly(ethylene glycol) succinate (FA-TPGS) and acidity-sensitive PEG-benzoic imine-octadecane (C18) (PEG-b-C18) conjugates. The developed FA-ZA/IR780@HPNs with high ZA and IR780 payloads not only showed excellent colloidal stability in a serum-containing milieu, but also promoted IR780-based photostability and photothermal conversion efficiency. Furthermore, for FA-ZA/IR780@HPNs under simulated physiological conditions, the premature leakage of IR780 and ZA molecules was remarkably declined. In a mimetic acidic tumor microenvironment, the uptake of FA-ZA/IR780@HPNs by FA receptor-overexpressed 4T1 breast cancer cells was remarkably promoted by PEG detachment combined with FA receptor-mediated endocytosis, thus effectively hindering migration of cancer cells and augmenting the anticancer efficacy of photothermal chemotherapy. Notably, the in vivo studies demonstrated that the FA-ZA/IR780@HPNs largely deposited at 4T1 tumor sites and profoundly suppressed tumor growth and metastasis without severe systemic toxicity upon near infrared (NIR)-triggered IR780-mediated hyperthermia integrated with ZA chemotherapy. This work presents a practical strategy to treat aggressive breast tumors with tumor-triggered targetable photothermal chemotherapy using FA-ZA/IR780@HPNs.

Amplifying "eat me signal" by immunogenic cell death for potentiating cancer immunotherapy

Immunogenic cell death (ICD) is a unique mode of cell death, which can release immunogenic damage-associated molecular patterns (DAMPs) and tumor-associated antigens to trigger long-term protective antitumor immune responses. Thus, amplifying "eat me signal" during tumor ICD cascade is critical for cancer immunotherapy. Some therapies (radiotherapy, photodynamic therapy (PDT), photothermal therapy (PTT), etc.) and inducers (chemotherapeutic agents, etc.) have enabled to initiate and/or facilitate ICD and activate antitumor immune responses. Recently, nanostructure-based drug delivery systems have been synthesized for inducing ICD through combining treatment of chemotherapeutic agents, photosensitizers for PDT, photothermal transformation agents for PTT, radiosensitizers for radiotherapy, etc., which can release loaded agents at an appropriate dosage in the designated place at the appropriate time, contributing to higher efficiency and lower toxicity. Also, immunotherapeutic agents in combination with nanostructure-based drug delivery systems can produce synergetic antitumor effects, thus potentiating immunotherapy. Overall, our review outlines the emerging ICD inducers, and nanostructure drug delivery systems loading diverse agents to evoke ICD through chemoradiotherapy, PDT, and PTT or combining immunotherapeutic agents. Moreover, we discuss the prospects and challenges of harnessing ICD induction-based immunotherapy, and highlight the significance of multidisciplinary and interprofessional collaboration to promote the optimal translation of this treatment strategy.

Current status of Fe-based MOFs in biomedical applications

Recently nanoparticle-based platforms have gained interest as drug delivery systems and diagnostic agents, especially in cancer therapy. With their ability to provide preferential accumulation at target sites, nanocarrier-constructed antitumor drugs can improve therapeutic efficiency and bioavailability. In contrast, metal-organic frameworks (MOFs) have received increasing academic interest as an outstanding class of coordination polymers that combine porous structures with high drug loading via temperature modulation and ligand interactions, overcoming the drawbacks of conventional drug carriers. FeIII-based MOFs are one of many with high biocompatibility and good drug loading capacity, as well as unique Fenton reactivity and superparamagnetism, making them highly promising in chemodynamic and photothermal therapy, and magnetic resonance imaging. Given this, this article summarizes the applications of FeIII-based MOFs in three significant fields: chemodynamic therapy, photothermal therapy and MRI, suggesting a logical route to new strategies. This article concludes by summarising the primary challenges and development prospects in these promising research areas.

Multifunctional Tumor-Targeting Carbon Dots for Tumor Microenvironment Activated Ferroptosis and Immunotherapy in Cancer Treatment

As an emerging cancer treatment strategy, ferroptosis is distinguished by the perturbation of lipid metabolism equilibrium and the accumulation of lipid peroxidation. However, the efficacy is consistently hindered by excessive GSH in the tumor microenvironment (TME). Here, this work designed and prepared multifunctional tumor-targeting carbon dots (FG-CDs@Cu) for ferroptosis and immunotherapy. Cu2+ in FG-CDs@Cu rapidly depletes high concentrations of GSH and inhibits glutathione peroxidase 4 (GPX4) expression in an acidic TME. Meanwhile, the generated Cu+ produced reactive oxygen species (ROS) through Fenton-like reaction. Due to the high efficiency of ROS production and GSH depletion, ferroptosis mediated by oxidative stress is significantly enhanced by FG-CDs@Cu in vivo, which can induce immunogenic cell death and promote CD8+ T cell infiltration. Meanwhile, the generated O2 effectively improves the hypoxic environment of the cells and leads to the reduction of hypoxia factor-1α (HIF-1α) expression, which activates the transformation of tumor-promoting M2-type tumor-associated macrophages (TAMs) to tumor-inhibiting M1-type TAMs, further enhancing the immune response and ferroptosis. The in vivo tests suggested that FG-CDs@Cu could efficiently suppress tumor growth in the mouse model and did not cause obvious toxicity. The combination with antiprogrammed death-ligand 1 (αPD-L1) synergy immune therapy could effectively restrain the growth of distal tumors, suggesting the significant potential of FG-CDs@Cu in augmenting ferroptosis and immunotherapy for efficacious cancer treatment.

Current status and prospects of MIL-based MOF materials for biomedicine applications

This article mainly reviews the biomedicine applications of two metal-organic frameworks (MOFs), MIL-100(Fe) and MIL-101(Fe). These MOFs have advantages such as high specific surface area, adjustable pore size, and chemical stability, which make them widely used in drug delivery systems. The article first introduces the properties of these two materials and then discusses their applications in drug transport, antibacterial therapy, and cancer treatment. In cancer treatment, drug delivery systems based on MIL-100(Fe) and MIL-101(Fe) have made significant progress in chemotherapy (CT), chemodynamic therapy (CDT), photothermal therapy (PTT), photodynamic therapy (PDT), immunotherapy (IT), nano-enzyme therapy, and related combined therapy. Overall, these MIL-100(Fe) and MIL-101(Fe) materials have tremendous potential and diverse applications in the field of biomedicine.

Functionalized nanohybrids with rod shape for improved chemo-phototherapeutic effect against cancer by sequentially generating singlet oxygen and carbon dioxide bubbles

The application of hybrid nanocarriers is expected to play an active role in improving treatment of chemotherapy and phototherapy. Herein, a nanohybrid with a core of mesoporous silica nanorods and shell of folate-functionalized zeolite imidazole framework (ZIF-8/FA) was synthesized via polydopamine (PDA)-mediated integration. A chemotherapeutic drug (DOX), bubble generator (NH4HCO3, ABC), and photosensitive agent (ICG) were simultaneously loaded into the delivery system to construct smart ZIF-8/FA-coated mesoporous silica nanorods (IDa-PRMSs@ZF). We found that ICG endowed the designed delivery system with a moderate photothermal conversion efficiency of 26.06% and the capacity to release 1O2. The produced hyperthermia caused ABC to decompose and further generate carbon dioxide bubbles, thereby facilitating DOX release, sequentially. Importantly, the underlying mechanism was also investigated using mathematical kinetic modeling. The tumor inhibition rate of IDa-PRMSs@ZF under NIR irradiation reached 83.8%. This study provides a promising strategy based on rod-shaped nanohybrids for effective combination antitumor therapy.

Nano-enabled colorectal cancer therapy

Colorectal cancer (CRC), one of the most common and deadliest diseases worldwide, poses a great health threat and social burden. The clinical treatments of CRC encompassing surgery, chemotherapy, and radiotherapy are challenged with toxicity, therapy resistance, and recurrence. In the past two decades, targeted therapy and immunotherapy have greatly improved the therapeutic benefits of CRC patients but they still suffer from drug resistance and low response rates. Very recently, gut microbiota regulation has exhibited a great potential in preventing and treating CRC, as well as in modulating the efficacy and toxicity of chemotherapy and immunotherapy. In this review, we provide a cutting-edge summary of nanomedicine-based treatment in colorectal cancer, highlighting the recent progress of oral and systemic tumor-targeting and/or tumor-activatable drug delivery systems as well as novel therapeutic strategies against CRC, including nano-sensitizing immunotherapy, anti-inflammation, gut microbiota modulation therapy, etc. Finally, the recent endeavors to address therapy resistance, metastasis, and recurrence in CRC were discussed. We hope this review could offer insight into the design and development of nanomedicines for CRC and beyond.

Indocyanine Green (ICG) and Colorectal Surgery: A Literature Review on Qualitative and Quantitative Methods of Usage

Background: Due to its many benefits, indocyanine green (ICG) has gained progressive popularity in operating rooms (ORs) globally. This literature review examines its qualitative and quantitative usage in surgical treatment. Method: Relevant terms were searched in five international databases (1. Pubmed, 2. Sciencedirect, 3. Scopus, 4. Oxfordjournals, 5. Reaxys) for a comprehensive literature review. The main benefits of using ICG in colorectal surgery are: intraoperative fluorescence angiography; fluorescence-guided lymph node involvement detection and the sentinel technique; the fluorescent emphasis of a minute liver tumour, counting just 200 tumour cells; facilitation of fistula diagnosis; and tumour tattooing. This methodology can also be used with quantitative characteristics such as maximum intensity, relative maximum intensity, and in-flow parameters such as time-to-peak, slope, and t1/2max. This article concludes that fluorescence surgery with ICG and near-infrared (NIR) light is a relatively new technology that improves anatomical and functional information, allowing more comprehensive and safer tumour removal and the preservation of important structures.

Nanoparticle-based drug delivery systems to enhance cancer immunotherapy in solid tumors

Immunotherapy has developed rapidly in solid tumors, especially in the areas of blocking inhibitory immune checkpoints and adoptive T-cell transfer for immune regulation. Many patients benefit from immunotherapy. However, the response rate of immunotherapy in the overall population are relatively low, which depends on the characteristics of the tumor and individualized patient differences. Moreover, the occurrence of drug resistance and adverse reactions largely limit the development of immunotherapy. Recently, the emergence of nanodrug delivery systems (NDDS) seems to improve the efficacy of immunotherapy by encapsulating drug carriers in nanoparticles to precisely reach the tumor site with high stability and biocompatibility, prolonging the drug cycle of action and greatly reducing the occurrence of toxic side effects. In this paper, we mainly review the advantages of NDDS and the mechanisms that enhance conventional immunotherapy in solid tumors, and summarize the recent advances in NDDS-based therapeutic strategies, which will provide valuable ideas for the development of novel tumor immunotherapy regimen.

Cu2+-pyropheophorbide-a-cystine conjugate-mediated multifunctional mesoporous silica nanoparticles for photo-chemodynamic therapy/GSH depletion combined with immunotherapy cancer

Photodynamic therapy (PDT) and chemodynamic therapy (CDT) can activate immunogenicity, so PDT and CDT combined immunotherapy is a promising treatment strategy. However, insufficient hydrogen peroxide activity, hypoxia, and overexpressed glutathione in the tumor microenvironment (TME) significantly impaired the ability to activate immunogenicity. Thus, in this paper, self-reinforcing conjugates Cu²⁺-Pyropheophorbide-a-Cysteine (CuPPaCC), combined synergetic NIR and pH triggered PDT/CDT with glutathione depletion ability was constructed. CuPPaCC was encapsulated in mesoporous silica, and spherical HSCuPPaCC nanoparticles were prepared by Hyaluronic acid (HA) on the silica surface by Schiff base modification. HSCuPPaCC has tumor-specific targeting via HA mediated. In acidic solution, the Schiff base of HSCuPPaCC is destroyed and CuPPaCC is released (>70%), with excellent pH response release function. The results of the MTT analysis showed that the PDT/CDT synergistic anti-tumor effect was significant. HSCuPPaCC was activated in TME, catalyzing the decomposition of hydrogen peroxide to generate hydroxyl radicals and oxygen, alleviating TME hypoxia, replenishing oxygen to PDT, and significantly down regulating hypoxia factor HIF-1α expression. HSCuPPaCC has an excellent dual ROS mechanism and a dual depleting GSH mechanism resulting in a surge in intracellular ROS levels to efficiently kill cancer cells, enhance the ability to induce immunogenicity, and make tumors more sensitive to checkpoint PD-L1 blockade therapy. With the CT26 mouse model, not only the primary tumor was eradicated, but also the distal tumor at the end of treatment was completely suppressed by HSCuPPaCC combined with anti-PD-L1 immune checkpoint blockade therapy.

Polysaccharide-Based Stimulus-Responsive Nanomedicines for Combination Cancer Immunotherapy

Cancer immunotherapy is a promising antitumor approach, whereas nontherapeutic side effects, tumor microenvironment (TME) intricacy, and low tumor immunogenicity limit its therapeutic efficacy. In recent years, combination immunotherapy with other therapies has been proven to considerably increase antitumor efficacy. However, achieving codelivery of the drugs to the tumor site remains a major challenge. Stimulus-responsive nanodelivery systems show controlled drug delivery and precise drug release. Polysaccharides, a family of potential biomaterials, are widely used in the development of stimulus-responsive nanomedicines due to their unique physicochemical properties, biocompatibility, and modifiability. Here, the antitumor activity of polysaccharides and several combined immunotherapy strategies (e.g., immunotherapy combined with chemotherapy, photodynamic therapy, or photothermal therapy) are summarized. More importantly, the recent progress of polysaccharide-based stimulus-responsive nanomedicines for combination cancer immunotherapy is discussed, with the focus on construction of nanomedicine, targeted delivery, drug release, and enhanced antitumor effects. Finally, the limitations and application prospects of this new field are discussed.

Nanomaterials for photothermal cancer therapy

Cancer has emerged as a pressing global public health issue, and improving the effectiveness of cancer treatment remains one of the foremost challenges of modern medicine. The primary clinical methods of treating cancer, including surgery, chemotherapy and radiotherapy, inevitably result in some adverse effects on the body. However, the advent of photothermal therapy offers an alternative route for cancer treatment. Photothermal therapy relies on photothermal agents with photothermal conversion capability to eliminate tumors at high temperatures, which offers advantages of high precision and low toxicity. As nanomaterials increasingly play a pivotal role in tumor prevention and treatment, nanomaterial-based photothermal therapy has gained significant attention owing to its superior photothermal properties and tumor-killing abilities. In this review, we briefly summarize and introduce the applications of common organic photothermal conversion materials (e.g., cyanine-based nanomaterials, porphyrin-based nanomaterials, polymer-based nanomaterials, etc.) and inorganic photothermal conversion materials (e.g., noble metal nanomaterials, carbon-based nanomaterials, etc.) in tumor photothermal therapy in recent years. Finally, the problems of photothermal nanomaterials in antitumour therapy applications are discussed. It is believed that nanomaterial-based photothermal therapy will have good application prospects in tumor treatment in the future.

Metal-Organic Frameworks Applications in Synergistic Cancer Photo-Immunotherapy

Conventional cancer therapies, such as radiotherapy and chemotherapy, can have long-term side effects. Phototherapy has significant potential as a non-invasive alternative treatment with excellent selectivity. Nevertheless, its applicability is restricted by the availability of effective photosensitizers and photothermal agents, and its low efficacy when it comes to avoiding metastasis and tumor recurrence. Immunotherapy can promote systemic antitumoral immune responses, acting against metastasis and recurrence; however, it lacks the selectivity displayed by phototherapy, sometimes leading to adverse immune events. The use of metal-organic frameworks (MOFs) in the biomedical field has grown significantly in recent years. Due to their distinct properties, including their porous structure, large surface area, and inherent photo-responsive properties, MOFs can be particularly useful in the fields of cancer phototherapy and immunotherapy. MOF nanoplatforms have successfully demonstrated their ability to address several drawbacks associated with cancer phototherapy and immunotherapy, enabling an effective and low-side-effect combinatorial synergistical treatment for cancer. In the coming years, new advancements in MOFs, particularly regarding the development of highly stable multi-function MOF nanocomposites, may revolutionize the field of oncology.

Novel construction of multifunctional photo-responsive and nucleic acid-triggered doxorubicin-releasing liposomes for cancer therapy

All-in-one nano theranostics integrating accurate diagnosis and combined therapy is promising for high-efficacy tumor treatment and receiving significant attention. In this study, we develop photo-controlled release liposomes with nucleic acid-triggered fluorescence and photoactivity for tumor imaging and synergistic antitumor therapy. Copper phthalocyanine as a photothermal agent is fused into lipid layers to prepare liposomes encapsulating cationic zinc phthalocyanine ZnPc(TAP)₄¹²⁺ and doxorubicin, followed by the modification of RGD peptide on the surface to obtain the final product RGD-CuPc:ZnPc(TAP)₄¹²⁺:DOX@LiPOs (RCZDL). RCZDL possesses favorable stability, significant photothermal effect, and photo-controlled release function through the characterization of physicochemical properties. It is shown that the fluorescence and ROS generation could be turned on by intracellular nucleic acid after illumination. RCZDL exhibits synergistic cytotoxicity, increased apoptosis, and significantly promoted cell uptake. Subcellular localization analysis indicates that ZnPc(TAP)₄¹²⁺ tends to be distributed in the mitochondria of HepG2 cells treated with RCZDL after exposure to light. The results of experiments in vivo on H22 tumor-bearing mice demonstrate that RCZDL had excellent tumor targeting, a prominent photothermal effect at the tumor sites, and synergistic antitumor efficiency. More importantly, little RCZDL has been found to be accumulated in the liver, and most were quickly metabolized by the liver. The results confirm that the proposed new intelligent liposomes provide a simple and cost-effective way for tumor imaging and combinatorial anticancer therapy.

Hybrid Nanomaterials for Cancer Immunotherapy

Nano-immunotherapy has been recognized as a highly promising strategy for cancer treatment in recent decades, which combines nanotechnology and immunotherapy to combat against tumors. Hybrid nanomaterials consisting of at least two constituents with distinct compositions and properties, usually organic and inorganic, have been engineered with integrated functions and enormous potential in boosting cancer immunotherapy. This review provides a summary of hybrid nanomaterials reported for cancer immunotherapy, including nanoscale metal-organic frameworks, metal-phenolic networks, mesoporous organosilica nanoparticles, metallofullerene nanomaterials, polymer-lipid, and biomacromolecule-based hybrid nanomaterials. The combination of immunotherapy with chemotherapy, chemodynamic therapy, radiotherapy, radiodynamic therapy, photothermal therapy, photodynamic therapy, and sonodynamic therapy based on hybrid nanomaterials is also discussed. Finally, the current challenges and the prospects for designing hybrid nanomaterials and their application in cancer immunotherapy are outlined.

Multifunctional nanoparticle for cancer therapy

Cancer is a complex disease associated with a combination of abnormal physiological process and exhibiting dysfunctions in multiple systems. To provide effective treatment and diagnosis for cancer, current treatment strategies simultaneously focus on various tumor targets. Based on the rapid development of nanotechnology, nanocarriers have been shown to exhibit excellent potential for cancer therapy. Compared with nanoparticles with single functions, multifunctional nanoparticles are believed to be more aggressive and potent in the context of tumor targeting. However, the development of multifunctional nanoparticles is not simply an upgraded version of the original function, but involves a sophisticated system with a proper backbone, optimized modification sites, simple preparation method, and efficient function integration. Despite this, many well-designed multifunctional nanoparticles with promising therapeutic potential have emerged recently. Here, to give a detailed understanding and analyzation of the currently developed multifunctional nanoparticles, their platform structures with organic or inorganic backbones were systemically generalized. We emphasized on the functionalization and modification strategies, which provide additional functions to the nanoparticle. We also discussed the application combination strategies that were involved in the development of nanoformulations with functional crosstalk. This review thus provides an overview of the construction strategies and application advances of multifunctional nanoparticles.

Immunotherapy-based novel nanoparticles in the treatment of gastrointestinal cancer: Trends and challenges

Gastrointestinal cancer (GIC) is the most common cancer with a poor prognosis. Currently, surgery is the main treatment for GIC. However, the high rate of postoperative recurrence leads to a low five-year survival rate. In recent years, immunotherapy has received much attention. As the only immunotherapy drugs approved by the Food and Drug Administration (FDA), immune checkpoint blockade (ICB) drugs have great potential in cancer therapy. Nevertheless, the efficacy of ICB treatment is greatly limited by the low immunogenicity and immunosuppressive microenvironment of GIC. Therefore, the targets of immunotherapy have expanded from ICB to increasing tumor immunogenicity, increasing the recruitment and maturation of immune cells and reducing the proportion of inhibitory immune cells, such as M2-like macrophages, regulatory T cells and myeloid-derived suppressor cells. Moreover, with the development of nanotechnology, a variety of nanoparticles have been approved by the FDA for clinical therapy, so novel nanodrug delivery systems have become a research focus for anticancer therapy. In this review, we summarize recent advances in the application of immunotherapy-based nanoparticles in GICs, such as gastric cancer, hepatocellular carcinoma, colorectal cancer and pancreatic cancer, and described the existing challenges and future trends.

Application of nanotechnology in the early diagnosis and comprehensive treatment of gastrointestinal cancer

Gastrointestinal cancer (GIC) is a common malignant tumour of the digestive system that seriously threatens human health. Due to the unique organ structure of the gastrointestinal tract, endoscopic and MRI diagnoses of GIC in the clinic share the problem of low sensitivity. The ineffectiveness of drugs and high recurrence rates in surgical and drug therapies are the main factors that impact the curative effect in GIC patients. Therefore, there is an urgent need to improve diagnostic accuracies and treatment efficiencies. Nanotechnology is widely used in the diagnosis and treatment of GIC by virtue of its unique size advantages and extensive modifiability. In the diagnosis and treatment of clinical GIC, surface-enhanced Raman scattering (SERS) nanoparticles, electrochemical nanobiosensors and magnetic nanoparticles, intraoperative imaging nanoparticles, drug delivery systems and other multifunctional nanoparticles have successfully improved the diagnosis and treatment of GIC. It is important to further improve the coordinated development of nanotechnology and GIC diagnosis and treatment. Herein, starting from the clinical diagnosis and treatment of GIC, this review summarizes which nanotechnologies have been applied in clinical diagnosis and treatment of GIC in recent years, and which cannot be applied in clinical practice. We also point out which challenges must be overcome by nanotechnology in the development of the clinical diagnosis and treatment of GIC and discuss how to quickly and safely combine the latest nanotechnology developed in the laboratory with clinical applications. Finally, we hope that this review can provide valuable reference information for researchers who are conducting cross-research on GIC and nanotechnology.

Copper-olsalazine metal-organic frameworks as a nanocatalyst and epigenetic modulator for efficient inhibition of colorectal cancer growth and metastasis

Despite the extensive explorations of nanoscale metal-organic frameworks (nanoMOFs) in drug delivery, the intrinsic bioactivity of nanoMOFs, such as anticancer activity, is severely underestimated owing to the overlooked integration of the hierarchical components including nanosized MOFs and molecular-level organic ligands and metal-organic complexes. Herein, we propose a de novo design of multifunctional bioactive nanoMOFs ranging from molecular to nanoscale level, and demonstrate this proof-of-concept by a copper-olsalazine (Olsa, a clinically approved drug for inflammatory bowel disease, here as a bioactive linker and DNA hypomethylating agent) nanoMOF displaying a multifaceted anticancer mechanism: (1) Cu-Olsa nanoMOF-mediated redox dyshomeostasis for enhanced catalytic tumor therapy, (2) targeting downregulation of cyclooxygenase-2 by the organic complex of Cu²⁺ and Olsa, and (3) Olsa-mediated epigenetic regulation. Cu-Olsa nanoMOF displayed an enzyme-like catalytic activity to generate cancericidal species ·OH and ¹O₂ from rich H₂O₂ in tumors, improved the expression of tumor suppressors TIMP3 and AXIN2 by epigenetic modulation, and fulfilled selective inhibition of colorectal cancer cells over normal cells. The hyaluronic acid-modified nanoMOF further verified the efficient suppression of CT26 colorectal tumor growth and metastasis in murine models. Overall, these results suggest that Olsa-based MOF presents a platform of epigenetic therapy-synergized nanomedicine for efficient cancer treatment and provides a powerful strategy for the design of intrinsically bioactive nanoMOFs. STATEMENT OF SIGNIFICANCE: Metal-organic frameworks (MOFs) with intrinsic bioactivities such as anticancer and antibacterial activity are of great interest. Herein, we reported a bioactive copper-olsalazine (Cu-Olsa) nanoMOF as a nanodrug for colorectal cancer treatment. This nanoMOF per se displayed enzyme-like catalytic activity to generate cancericidal species ·OH and ¹O₂ from rich H₂O₂ in tumors for nanocatalytic tumor therapy. Upon dissociation into small molecular copper-organic complex and olsalazine in cancer cells, COX-2 inhibition and epigenetic modulation were fulfilled for selective inhibition of colorectal cancer growth and metastasis.

Recent Progress in Second Near-Infrared (NIR-II) Fluorescence Imaging in Cancer

Cancer continues to be one of the leading causes of death worldwide, and its incidence is on the rise. Although cancer diagnosis and therapy have advanced significantly in recent decades, it is still a challenge to achieve the accurate identification and localization of cancer and to complete tumor elimination with a maximum preservation of normal tissue. Recently, second near-infrared region (NIR-II, 1000-1700 nm) fluorescence has shown great application potential in cancer theranostics due to its inherent advantages, such as great penetration capacity, minimal tissue absorption and scattering, and low autofluorescence. With the development of fluorescence imaging systems and fluorescent probes, tumor detection, margin definition, and individualized therapy can be achieved quickly, enabling an increasingly accurate diagnosis and treatment of cancer. Herein, this review introduces the role of NIR-II fluorescence imaging in cancer diagnosis and summarizes the representative applications of NIR-II image-guided treatment in cancer therapy. Ultimately, we discuss the present challenges and future perspectives on fluorescence imaging in the field of cancer theranostics and put forward our opinions on how to improve the accuracy and efficiency of cancer diagnosis and therapeutics.

A nanosized photothermal responsive core-shell carbonized polymer dots based on poly(N-isopropylacrylamide) for light-triggered drug release

Core-shell nanocomposites are one of the most important achievements in the fast-growing field of nanotechnology. The combination of multi-responsive nano-shell with luminescent and photothermal core has led to promising applications in various fields such as optics, electronics and medicine. In this work, a nanosized core-shell system composed by carbonized dots core and poly(N-isopropylacrylamide) shell was developed and the photothermal triggered release of doxorubicin was demonstrated. The system was fully characterized by H¹-NMR, DLS, Z-potential, AFM, optical absorption and fluorescence measurements. A photothermal conversion efficiency (η) value of about 67.9% and a doxorubicin photo-release rate value of about 1.0% min^-1 were measured. Molecular dynamic (MD) simulations data were in agreement with experimental results, at 310 K the coil-to-globule transition and a consequent desorption of doxorubicin from the polymer were observed. Both the radius of gyration and the fluctuation of the distance doxorubicin-PNIPAM pointed that the temperature above the LCST and the acid pH facilitated the polymer transition. Moreover, MD simulations and experimental data suggested an influence on the lower critical solution temperature (LCST) exerted by the number of polymer chains anchored to the carbon core.