Metal-polyphenol nanodots loaded hollow MnO2 nanoparticles with a "dynamic protection" property for enhanced cancer chemodynamic therapy

Novel 131-iodine labeled and ultrasound-responsive nitric oxide and reactive oxygen species controlled released nanoplatform for synergistic sonodynamic/nitric oxide/chemodynamic/radionuclide therapy

Nitric oxide (NO) and reactive oxygen species (ROS) embody excellent potential in cancer therapy. However, as a small molecule, their targeted delivery and precise, controllable release are urgently needed to achieve accurate cancer therapy. In this paper, a novel US-responsive bifunctional molecule (SD) and hyaluronic acid-modified MnO2 nanocarrier was developed, and a US-responsive NO and ROS controlled released nanoplatform was constructed. US can trigger SD to release ROS and NO simultaneously at the tumor site. Thus, SD served as acoustic sensitizer for sonodynamic therapy and NO donor for gas therapy. In the tumor microenvironment, the MnO2 nanocarrier can effectively deplete the highly expressed GSH, and the released Mn2+ can make H2O2 to produce .OH by Fenton-like reaction, which exhibited a strong chemodynamic effect. The high concentration of ROS and NO in cancer cell can induce cancer cell apoptosis ultimately. In addition, toxic ONOO-, which was generated by the reaction of NO and ROS, can effectively cause mitochondrial dysfunction, which induced the apoptosis of tumor cells. The 131I was labeled on the nanoplatform, which exhibited internal radiation therapy for tumor therapy. In -vitro and -vivo experiments showed that the nanoplatform has enhanced biocompatibility, and efficient anti-tumor potential, and it achieves synergistic sonodynamic/NO/chemodynamic/radionuclide therapy for cancer.

Ultrasensitive detection platform for Staphylococcus aureus based on DNAzyme tandem blocking CRISPR/Cas12a system

Detection methods based on CRISPR/Cas12a have been widely developed in the application of pathogenic microorganisms to guarantee food safety and public health. For sensitive detection, the CRISPR-based strategies are often in tandem with amplification methods. However, that may increase the detection time and the process may introduce nucleic acid contamination resulting in non-specific amplification. Herein, we established a sensitive S. aureus detection strategy based on the CRISPR/Cas12a system combined with DNAzyme. The activity of Cas12a is blocked by extending the spacer of crRNA (bcrRNA) and can be reactivated by Mn2+. NH2-modified S. aureus-specific aptamer was loaded on the surface of Fe3O4 MNPs (apt-Fe3O4 MNPs) and MnO2 NPs (apt-MnO2 NPs) by EDC/NHS chemistry. The S. aureus was captured to form apt-Fe3O4 MNPs/S. aureus/apt-MnO2 NPs complex and then MnO2 NPs were etched to release Mn2+ to activate DNAzyme. The active DNAzyme can cleave the hairpin structure in bcrRNA to recover the activity of the CRISPR/Cas system. By initiating the whole detection process by generating Mn2+ through nanoparticle etching, we established a rapid detection assay without nucleic acid extraction and amplification process. The proposed strategy has been applied in the ultrasensitive quantitative detection of S. aureus and has shown good performance with an LOD of 5 CFU/mL in 29 min. Besides, the proposed method can potentially be applied to other targets by simply changing the recognition element and has the prospect of developing a universal detection strategy.

A multifunctional cascade enzyme system for enhanced starvation/chemodynamic combination therapy against hypoxic tumors

Starvation therapy has shown promise as a cancer treatment, but its efficacy is often limited when used alone. In this work, a multifunctional nanoscale cascade enzyme system, named CaCO3@MnO2-NH2@GOx@PVP (CMGP), was fabricated for enhanced starvation/chemodynamic combination cancer therapy. CMGP is composed of CaCO3 nanoparticles wrapped in a MnO2 shell, with glucose oxidase (GOx) adsorbed and modified with polyvinylpyrrolidone (PVP). MnO2 decomposes H2O2 in cancer cells into O2, which enhances the efficiency of GOx-mediated starvation therapy. CaCO3 can be decomposed in the acidic cancer cell environment, causing Ca2+ overload in cancer cells and inhibiting mitochondrial metabolism. This synergizes with GOx to achieve more efficient starvation therapy. Additionally, the H2O2 and gluconic acid produced during glucose consumption by GOx are utilized by MnO2 with catalase-like activity to enhance O2 production and Mn2+ release. This process accelerates glucose consumption, reactive oxygen species (ROS) generation, and CaCO3 decomposition, promoting the Ca2+ release. CMGP can alleviate tumor hypoxia by cycling the enzymatic cascade reaction, which increases enzyme activity and combines with Ca2+ overload to achieve enhanced combined starvation/chemodynamic therapy. In vitro and in vivo studies demonstrate that CMGP has effective anticancer abilities and good biosafety. It represents a new strategy with great potential for combined cancer therapy.

Tumor microenvironment-regulated drug delivery system combined with sonodynamic therapy for the synergistic treatment of breast cancer

Co-loading of sonosensitizers and chemotherapeutic drugs into nanocarriers can improve the biocompatibilities, stabilities, and targeting of drugs and reduce the adverse reactions of drugs, providing a robust platform to orchestrate the synergistic interplay between chemotherapy and sonodynamic therapy (SDT) in cancer treatment. In this regard, biodegradable manganese dioxide (MnO2) has attracted widespread attention because of its unique properties in the tumor microenvironment (TME). Accordingly, herein, MnO2 nanoshells with hollow mesoporous structures (H-MnO2) were etched to co-load hematoporphyrin monomethyl ether (HMME) and doxorubicin (DOX), and DOX/HMME-HMnO2@bovine serum albumin (BSA) obtained after simple BSA modification of DOX/HMME-HMnO2 exhibited excellent hydrophilicity and dispersibility. H-MnO2 rapidly degraded in the weakly acidic TME, releasing loaded HMME and DOX, and catalysed the decomposition of H2O2 abundantly present in TME, producing oxygen (O2) in situ, significantly increasing O2 concentration and downregulating the hypoxia-inducible factor 1α (HIF-1α). After irradiation of the tumor area with low-frequency ultrasound, the drug delivery efficiency of DOX/HMME-HMnO2@BSA substantially increased, and the excited HMME generated a large amount of reactive oxygen species (ROS), which caused irreversible damage to tumor cells. Moreover, the cell death rate exceeded 60% after synergistic SDT-chemotherapy. Therefore, the pH-responsive nanoshells designed in this study can realize drug accumulation in tumor regions by responding to TME and augment SDT-chemotherapy potency for breast cancer treatment by improving hypoxia in tumors. Thus, this study provides theoretical support for the development of multifunctional nanocarriers and scientific evidence for further exploration of safer and more efficient breast cancer treatments.

Emerging Chemodynamic Nanotherapeutics for Cancer Treatment

Chemodynamic therapy (CDT) has emerged as a transformative paradigm in the realm of reactive oxygen species -mediated cancer therapies, exhibiting its potential as a sophisticated strategy for precise and effective tumor treatment. CDT primarily relies on metal ions and hydrogen peroxide to initiate Fenton or Fenton-like reactions, generating cytotoxic hydroxyl radicals. Its notable advantages in cancer treatment are demonstrated, including tumor specificity, autonomy from external triggers, and a favorable side-effect profile. Recent advancements in nanomedicine are devoted to enhancing CDT, promising a comprehensive optimization of CDT efficacy. This review systematically elucidates cutting-edge achievements in chemodynamic nanotherapeutics, exploring strategies for enhanced Fenton or Fenton-like reactions, improved tumor microenvironment modulation, and precise regulation in energy metabolism. Moreover, a detailed analysis of diverse CDT-mediated combination therapies is provided. Finally, the review concludes with a comprehensive discussion of the prospects and intrinsic challenges to the application of chemodynamic nanotherapeutics in the domain of cancer treatment.

Dual-Responsive hollow mesoporous organosilicon nanocarriers for photodynamic therapy

HYPOTHESIS

The nano-delivery platform, -SS-HMONs@MB@MnO2 nanoparticles (SMM NPs) loaded with methylene blue (MB) as photosensitizer have excellent photodynamic therapy (PDT) effect. The disulfide bond and MnO2 give the shell redox-responsive properties. SMM NPs consume glutathione (GSH) in tumor cells, reducing the scavenging of reactive oxygen species (ROS) by GSH and enhancing the PDT effect of MB.

EXPERIMENTS

The GSH dual-responsive nano-delivery platform, was designed and constructed by using disulfide-doped hollow mesoporous organosilicon nanoparticles (-SS-HMONs) as intermediate responsive layer, loaded with MB as photosensitizer and coated with MnO2 as shells. The MB photosensitizer release and GSH response were characterized. The PDT effect of nanoparticles was evaluated.

FINDINGS

The SMM NPs were uniform in size and well dispersed. The nanoparticles could react with GSH, leading to the decomposition of MnO2 shells and the breakage of disulfide bonds in -SS-HMONs, resulted in the release of MB photosensitizer. The cell experiment showed that SMM NPs had good ROS generating ability and PDT effect after being sucked by tumor cells, which could effectively kill tumor cells. However, in vivo experiments demonstrated that SMM NPs showed slight inhibition on tumor growth. The actual effect in animals was different from the effect in cells.

Properties of konjac glucomannan/curdlan-based emulsion films incorporating camellia oil and the preservation effect as coatings on 'Kyoho' grapes

The strategy of emulsion coating was used for grape preservation. Camellia oil (CO) was incorporated with KGM/curdlan (KC) to fabricate KC-CO emulsion systems. KC-CO emulsions were analyzed by droplet size distribution and confocal laser scanning microscopy (CLSM), and KC-CO films were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), mechanical properties, dissolution, gas permeability, water contact angle (WCA). KC-CO coating was used for preservation of 'Kyoho' grapes. The results indicated that the addition of CO had a positive effect on KC system. CO could form a uniform emulsion with KC, and the droplets were evenly dispersed in the KC matrix. KC-CO films displayed a continuous microstructure, and elongation at break (EAB) was improved, while tensile strength decreased. The dissolution, water vapor permeability (WVP), and WCA were significantly enhanced, while the permeability of oxygen and carbon dioxide exhibited no advantage compared with KC film. KC-CO-10 possessed optimal properties and was selected as an emulsion coating for preservation. The results suggested that KC-CO-10 significantly maintained the appearance, total solid and acid content of 'Kyoho' grapes, and delayed the weight loss and firmness decrease. This study contributed to the understanding of polysaccharide-lipid emulsion system and the applications.

Tumor-targeting polymer nanohybrids with amplified ROS generation for combined photodynamic and chemodynamic therapy

Reactive oxygen species (ROS) generating strategies have been widely adopted for cancer therapy, but therapeutic efficacies are often low due to the complicated tumor microenvironment. In this study, we present the development of tumor-targeting polymer nanohybrids that amplify ROS generation by combining photodynamic therapy (PDT) and chemodynamic therapy (CDT) for cancer treatment. Such polymer nanohybrids contained three main components: a semiconducting polymer (SP) that acted as the photosensitizer for PDT, manganese dioxide (MnO2) that acted as the catalyst for CDT, and transferrin that mediated tumor targeting via binding to transferrin receptors overexpressed on the surface of tumor cells. The formed nanohybrids (TSM) showed obviously enhanced accumulation efficacy in tumor sites because of their targeting ability. In tumor sites, TSM produced singlet oxygen (1O2) under near-infrared (NIR) laser irradiation and a hydroxyl radical (˙OH) via reacting with hydrogen peroxide (H2O2), which resulted in amplified generation of ROS to achieve PDT/CDT combinational therapy. The growth of subcutaneous 4T1 tumors was remarkably inhibited via TSM-mediated treatment. In addition, this therapeutic efficacy could suppress tumor metastasis in the liver and lungs. This study presents a targeting hybrid nanoplatform to combine different ROS generating strategies for effective cancer therapy.

A pH-Sensitive Nanoparticle as Reactive Oxygen Species Amplifier to Regulate Tumor Microenvironment and Potentiate Tumor Radiotherapy

Background

Radiotherapy is a widely used clinical tool for tumor treatment but can cause systemic toxicity if excessive radiation is administered. Although numerous nanoparticles have been developed as radiosensitizers to reduce the required dose of X-ray irradiation, they often have limitations, such as passive reliance on radiation-induced apoptosis in tumors, and little consider the unique tumor microenvironment that contributes radiotherapy resistance.

Methods

In this study, we developed and characterized a novel self-assembled nanoparticle containing dysprosium ion and manganese ion (Dy/Mn-P). We systematically investigated the potential of Dy/Mn-P nanoparticles (NPs) as a reactive oxygen species (ROS) amplifier and radiosensitizer to enhance radiation therapy and modulate the tumor microenvironment at the cellular level. Additionally, we evaluated the effect of Dy/Mn-P on the stimulator of interferon genes (STING), an innate immune signaling pathway.

Results

Physicochemical analysis demonstrated the prepared Dy/Mn-P NPs exhibited excellent dispersibility and stability, and degraded rapidly at lower pH values. Furthermore, Dy/Mn-P was internalized by cells and exhibited selective toxicity towards tumor cells compared to normal cells. Our findings also revealed that Dy/Mn-P NPs improved the tumor microenvironment and significantly increased ROS generation under ionizing radiation, resulting in a ~70% increase in ROS levels compared to radiation therapy alone. This enhanced ROS generation inhibited ~92% of cell clone formation and greatly contributed to cytoplasmic DNA exposure. Subsequently, the activation of the STING pathway was observed, leading to the secretion of pro-inflammatory immune factors and maturation of dendritic cells (DCs).

Conclusion

Our study demonstrates that Dy/Mn-P NPs can potentiate tumor radiotherapy by improving the tumor microenvironment and increasing endogenous ROS levels within the tumor. Furthermore, Dy/Mn-P can amplify the activation of the STING pathway during radiotherapy, thereby triggering an anti-tumor immune response. This novel approach has the potential to expand the application of radiotherapy in tumor treatment.

Metal-DNA Nanocomplexes Enhance Chemo-dynamic Therapy by Inhibiting Autophagy-Mediated Resistance

Chemo-dynamic therapy (CDT) based on the Fenton or Fenton-like reaction has emerged as a promising approach for cancer treatment. However, autophagy-mediated self-protection mechanisms of cancer cells pose a significant challenge to the efficacy of CDT. Herein, we developed metal-DNA nanocomplexes (DACs-Mn) to enhance CDT via DNAzyme inhibition of autophagy. Specifically, Mn-based catalyst in DACs-Mn was used to generate highly hydroxyl radicals (⋅OH) that kill cancer cells, while the ATG5 DNAzyme incorporated into DACs-Mn inhibited the expression of autophagy-associated proteins, thereby improving the efficacy of CDT. By disrupting the self-protective pathway of cells under severe oxidative stress, this novel approach of DACs-Mn was found to synergistically enhance CDT in both in vitro and in vivo models, effectively amplifying tumor-specific oxidative damage. Notably, the Metal-DNA nanocomplexes can also induce immunogenic cell death (ICD), thereby inhibiting tumor metastasis. Specifically, in a bilateral tumor model in mice, the combined approach of CDT and autophagy inhibition followed by immune checkpoint blockade therapy shown significant potential as a novel and effective treatment modality for primary and metastatic tumors.

Optimized strategies of ROS-based nanodynamic therapies for tumor theranostics

Reactive oxygen species (ROS) play a crucial role in regulating the metabolism of tumor growth, metastasis, death and other biological processes. ROS-based nanodynamic therapies (NDTs) are becoming attractive due to non-invasive, low side effects and tumor-specific advantages. NDTs have rapidly developed into numerous branches, such as photodynamic therapy, chemodynamic therapy, sonodynamic therapy and so on. However, the complexity of the tumor microenvironment and the limitations of existing sensitizers have greatly restricted the therapeutic effects of NDTs, which heavily rely on ROS levels. To address the limitations of NDTs, various strategies have been developed to increase ROS yield, which is an urgent aspect for the positive development of NDTs. In this review, the nanodynamic potentiation strategies in terms of unique properties and universalities of NDTs are comprehensively outlined. We mainly summarize the current dilemmas faced by each NDT and the respective solutions. Meanwhile, the NDTs universalities-based potentiation strategies and NDTs-based combined treatments are elaborated. Finally, we conclude with a discussion of the key issues and challenges faced in the development and clinical transformation of NDTs.

Formation and detection of biocoronas in the food industry and their fate in the human body

The rapid advancement of nanotechnology has opened up new avenues for applications in all stages of the food industry. Over the past decade, extensive research has emphasized that when nanoparticles (NPs) enter organisms, they spontaneously adsorbed biomolecules, leading to the formation of biocorona. This paper provided a detailed review of the process of biocorona formation in the food industry, including their classification and influencing factors. Additionally, various characterization methods to investigated the morphology and structure of biocoronas were introduced. As a real state of food industry nanoparticles in biological environments, the biocorona causes structural transformations of biomolecules bound to NPs, thus affecting their fate in the body. It can either promote or inhibit enzyme activity in the human environment, and may also positively or negatively affect the cellular uptake and toxicity of NPs. Since NPs present in the food industry will inevitably enter the human body, further investigations on biocoronas will offer valuable insights and perspectives on the safety of incorporating more NPs into the food industry.

Inhibitory mechanism of carboxymethyl chitosan-lotus seedpod oligomeric procyanidin nanoparticles on dietary advanced glycation end products released from glycated casein during digestion

Lotus seedpod oligomeric procyanidins (LSOPC) are potent inhibitors of advanced glycation end products (AGEs), whose gastrointestinal susceptibility to degradation limits their use in vivo. In this study, carboxymethyl chitosan-lotus seedpod oligomeric procyanidin nanoparticles (CMC-LSOPC NPs) were constructed with a binding ratio of 1:6.51. CMC-LSOPC NPs significantly inhibited the release of AGEs from glycated casein (G-CS) during digestion, increasing the inhibition rate by 25.76% in the gastric phase and by 14.33% in the intestinal phase compared with LSOPC alone. To further investigate the inhibition mechanism, fluorescence microscopy, scanning electron microscopy and FTIR were used to find that CMC-LSOPC NPs could form cohesions to encapsulate G-CS in the gastric phase and hinder G-CS hydrolysis. In the intestinal phase, LSOPC was targeted for release and bound to trypsin through hydrophobic interactions and hydrogen bonding, resulting in protein peptide chain rearrangement, changes in secondary structure and significant reduction in trypsin activity. In addition, CMC-LSOPC NPs increased the antioxidant capacity of digestive fluid and could reduce the oxidative stress in the gastrointestinal tract caused by the release of AGEs. It's the first time that CMC-LSOPC NPs were constructed to enhance the stability of LSOPC during digestion and explain the mechanism by which CMC-LSOPC NPs inhibit the release of AGEs from G-CS in both stomach and intestine. This finding will present a novel approach for reducing AGEs during gastrointestinal digestion.

Mn-Doped Nano-Hydroxyapatites as Theranostic Agents with Tumor pH-Amplified MRI-Signal Capabilities for Guiding Photothermal Therapy

Background

The integration of diagnostic and therapeutic functions into a biosafe nanoplatform with intelligent response functions at the tumor microenvironment (TME) is a promising strategy for cancer therapy.

Methods

Mn-doped nano-hydroxyapatite (nHAPMn) nanoparticles were successfully prepared via a simple coprecipitation method for magnetic resonance imaging (MRI)-guided photothermal therapy. This study is the first to report on the use of Mn to render biodegradable hydroxyapatite suitable for MRI and effective photothermal therapy (PTT) simultaneously by regulating the pH of nHAPMn during the preparation process.

Results

Combined with near-infrared (NIR) laser irradiation, a photothermal conversion efficiency of 26% and effective photothermal lethality in vitro were achieved. Moreover, the degradation of nHAPMn led to the release of Mn ions and amplified the MRI signals in an acidic TME, which confirmed that nHAPMn had a good pH-responsive MRI capacity in solid tumors. In animal experiments, tumors in the nHAPMn5+NIR group completely abated after 14 days of treatment, with no significant recurrence during the experiment.

Conclusion

Therefore, nHAPMn is promising as a nanotheranostic agent and can be effective in clinical diagnosis and therapy for treating cancer.

Extraction Methods, Properties, Functions, and Interactions with Other Nutrients of Lotus Procyanidins: A Review

Lotus procyanidins, natural polyphenolic compounds isolated from the lotus plant family, are widely recognized as potent antioxidants that scavenge free radicals in the human body and exhibit various pharmacological effects, such as anti-inflammatory, anticancer, antiobesity, and hypoglycemic. With promising applications in food and healthcare, lotus procyanidins have attracted extensive attention in recent years. This review provides a comprehensive summary of current research on lotus procyanidins, including extraction methods, properties, functions, and interactions with other nutrient components. Furthermore, this review offers an outlook on future research directions, providing ideas and references for the exploitation and utilization of lotus.

Inhibition of advance glycation end products formation, gastrointestinal digestion, absorption and toxicity: A comprehensive review

Advanced glycation end-products (AGEs) are the final products of the non-enzymatic interaction between reducing sugars and amino groups in proteins, lipids and nucleic acids. In numerous diseases, such as diabetes, neuropathy, atherosclerosis, aging, nephropathy, retinopathy, and chronic renal illness, accumulation of AGEs has been proposed as a pathogenic mechanism of inflammation, oxidative stress, and structural tissue damage leading to chronic vascular issues. Current studies on the inhibition of AGEs mainly focused on food processing. However, there are few studies on the inhibition of AGEs during digestion, absorption and metabolism although there are still plenty of AGEs in our body with our daily diet. This review comprehensively expounded AGEs inhibition mechanism based on the whole process of digestion, absorption and metabolism by polyphenols, amino acids, hydrophilic colloid, carnosine and other new anti-glycation agents. Our study will provide a ground-breaking perspective on mediation or inhibition AGEs.

Molecular Mechanism of Lotus Seedpod Oligomeric Procyanidins Inhibiting the Absorption of Oligopeptide-Advanced Glycation End Products

Research on advanced glycation end product (AGEs) inhibition has generally focused on food processing, but many protein-AGEs will still be taken. Oligopeptide (OLP)-AGEs, as the main form after digestion, will damage human health once absorbed. Here, we investigated the ability of lotus seedpod oligomeric procyanidins (LSOPC) to inhibit the absorption of the OLP-AGEs and elucidated the underlying mechanism. Our results showed that the inhibition rate of LSOPC on the absorption of OLP-AGEs was about 50 ± 5.38%. 0.1, 0.2, and 0.3 mg/mL could upregulate the expression of ZO-1 and downregulate the expression of PepT1 and clathrin. Molecular docking showed that LSOPC could compete with the binding of OLP-AGEs to PepT1 and AP-2, thus inhibiting the absorption of OLP-AGEs. Furthermore, the interaction of LSOPC with the OLP-AGEs reduced the surface hydrophobicity of OLP-AGEs. It altered the secondary structure of the OLP-AGEs, thus weakening the affinity of the OLP-AGEs to the transporter protein to inhibit the absorption of OLP-AGEs. Together, our data revealed potential mechanisms by which LSOPC inhibit the absorption of OLP-AGEs and opened up new perspectives on the application of LSOPC in reducing the increasing health risks posed by OLP-AGEs.

Tailored Beta-Lapachone Nanomedicines for Cancer-Specific Therapy

Nanotechnology shows the power to improve efficacy and reduce the adverse effects of anticancer agents. As a quinone-containing compound, beta-lapachone (LAP) is widely employed for targeted anticancer therapy under hypoxia. The principal mechanism of LAP-mediated cytotoxicity is believed due to the continuous generation of reactive oxygen species with the aid of NAD(P)H: quinone oxidoreductase 1 (NQO1). The cancer selectivity of LAP relies on the difference between NQO1 expression in tumors and that in healthy organs. Despite this, the clinical translation of LAP faces the problem of narrow therapeutic window that is challenging for dose regimen design. Herein, the multifaceted anticancer mechanism of LAP is briefly introduced, the advance of nanocarriers for LAP delivery is reviewed, and the combinational delivery approaches to enhance LAP potency in recent years are summarized. The mechanisms by which nanosystems boost LAP efficacy, including tumor targeting, cellular uptake enhancement, controlled cargo release, enhanced Fenton or Fenton-like reaction, and multidrug synergism, are also presented. The problems of LAP anticancer nanomedicines and the prospective solutions are discussed. The current review may help to unlock the potential of cancer-specific LAP therapy and speed up its clinical translation.

Recent Advances of Metal-Polyphenol Coordination Polymers for Biomedical Applications

Nanomedicine has provided cutting-edge technologies and innovative methods for modern biomedical research, offering unprecedented opportunities to tackle crucial biomedical issues. Nanomaterials with unique structures and properties can integrate multiple functions to achieve more precise diagnosis and treatment, making up for the shortcomings of traditional treatment methods. Among them, metal-polyphenol coordination polymers (MPCPs), composed of metal ions and phenolic ligands, are considered as ideal nanoplatforms for disease diagnosis and treatment. Recently, MPCPs have been extensively investigated in the field of biomedicine due to their facile synthesis, adjustable structures, and excellent biocompatibility, as well as pH-responsiveness. In this review, the classification of various MPCPs and their fabrication strategies are firstly summarized. Then, their significant achievements in the biomedical field such as biosensing, drug delivery, bioimaging, tumor therapy, and antibacterial applications are highlighted. Finally, the main limitations and outlooks regarding MPCPs are discussed.

Polydopamine nanoparticles coated with a metal-polyphenol network for enhanced photothermal/chemodynamic cancer combination therapy

Polydopamine nanoparticles (PDA NPs) are commonly used for photothermal therapy (PTT) of cancer because of their good biocompatibility and photothermal conversion capability. However, it is difficult to achieve a good tumor inhibition effect with a single PTT of PDA. Therefore, in this work, we prepared a combined anticancer nanosystem for enhanced chemodynamic therapy (CDT)/PTT by coating PDAs with an (-)-epigallocatechin gallate (EGCG)/iron (Fe) metal-polyphenol network (MPN). The MPN shell of this nanosystem named EGCG@PDA is degraded by the weakly acidic environment intracellular, releasing EGCG and Fe³⁺. EGCG inhibits the expression of heat shock proteins (HSPs) in cancer cells, thus eliminating their thermal protection against cancer cells for enhanced PTT. Meanwhile, the reductive EGCG can also reduce Fe³⁺ to Fe²⁺, to catalyze the decomposition of overexpressed hydrogen peroxide (H₂O₂) in cancer cells to generate strong oxidative hydroxyl radicals (OH), i.e., catalyzing the Fenton reaction, for CDT. After the Fenton reaction, the re-oxidized Fe ions can be reduced again by EGCG and reused to catalyze the Fenton reaction, which can achieve enhanced CDT. Both in vitro and in vivo studies have shown that EGCG@PDA has low dark toxicity and good anticancer effects. It is expected to be used for precision cancer therapy.

Copper(II) complex enhanced chemodynamic therapy through GSH depletion and autophagy flow blockade

Three copper(II) complexes C1-C3 were synthesized and fully characterized as chemodynamic therapy (CDT) anticancer agents. C1-C3 showed greater cytotoxicity than their ligands toward SK-OV-3 and T24 cells. Particularly, C2 showed high cytotoxicity toward T24 cells and low cytotoxicity toward normal human HL-7702 and WI-38 cells. Mechanistic studies demonstrated that C2 oxidized GSH to GSSG and produced ˙OH, which induced mitochondrial dysfunction and ER stress, finally leading to apoptosis of T24 cells. In addition, C2 inhibited autophagy by blocking autophagy flow, thereby closing the self-protection pathway of oxidative stress to enhance CDT. Importantly, C2 significantly inhibited T24 tumor growth with 57.1% inhibition in a mouse xenograft model. C2 is a promising lead as a potential CDT anticancer agent.