Prussian blue analog with separated active sites to catalyze water driven enhanced catalytic treatments

Photothermally-enhanced ferroptotic-chemo therapy enabled by ZIF-derived multizyme

A multi-functional single-Fe-atom nanozyme (Fe-SAzyme) is designed, integrating the near-infrared photothermal property, the ability to carry chemoagent (doxorubicin - DOX), and nanocatalytic activities mimicking peroxidase, oxidase, and glutathione oxidase. The nanocatalytic activities act cooperatively to effectively produce cytotoxic radicals in the tumor microenvironment (TME), thereby leading to ferroptosis of cancer cells. The photothermal effect not only enhances the nanocatalytic therapy but also enables photothermal therapy. And release of DOX upon triggering by TME and the Fe-SAzyme activities enables chemotherapy to induce apoptosis of cancer cells. Such targeted and synergistic multi-modality treatment achieves complete tumor elimination without obvious side effects. Further, the underlying working mechanism is carefully revealed both theoretically and experimentally.

Size and crystallinity effects on enzymatic activity and anti-inflammatory properties of cysteine-assisted Prussian blue nanozymes

Prussian blue nanoparticles (PB NPs) exhibit multiple enzymatic activities, such as superoxide dismutase-like, catalase-like, and peroxidase-like activities, which enable them to effectively scavenge reactive oxygen species (ROS) and demonstrate anti-inflammatory effects. To further enhance the enzymatic activity of PB NPs, it is crucial to explore the relationship between their physicochemical properties, such as size and crystallinity, and their enzymatic performance. In this study, PB NPs were synthesized using different pH levels and varying concentrations of cysteine (Cys) as a stabilizer. As the size decreases, crystallinity is gradually reduced, and defects increase. Cys-PB NPs with a smaller size and lower crystallinity exhibited high peroxidase-like activity, effectively reducing inflammation and scavenging intracellular ROS in vitro. Additionally, the stability of Cys-PB NPs plays a critical role in their anti-inflammatory properties, with higher stability favouring anti-inflammatory effect.

Near-infrared-triggered release of self-accelerating cascade nanoreactor delivered by macrophages for synergistic tumor photothermal therapy/starvation therapy/chemodynamic therapy

Macrophages have emerged as promising cellular vehicles for the delivery of therapeutic agents to tumor sites. However, the cytotoxicity of therapeutic agents toward the cellular carriers and the effective release of therapeutic agents at the tumor site remain the main challenges faced by macrophage-mediated drug delivery systems. Herein, a near-infrared (NIR)-triggered release of self-accelerating cascade nanoreactor (HCFG) delivered by macrophages (HCFG@R) was developed for synergistic tumor photothermal therapy (PTT)/starvation therapy (ST)/chemodynamic therapy (CDT). Attributed to the inherent tumor tropism of macrophages, HCFG@R could accumulate in tumor tissues and subsequently be disrupted by NIR laser, allowing the release of HCFG nanoparticles (NPs) from macrophage carriers. The released HCFG catalyzed the generation of O2 from hydrogen peroxide (H2O2), which in turn enhanced glucose oxidase (GOx)-mediated ST. Simultaneously, the H2O2 and gluconic acid generated by ST could promote the production of hydroxyl radicals (·OH), thereby improving the therapeutic effect of CDT. The present study provides an innovative strategy for enhanced PTT/ST/CDT synergistic therapy through a macrophage-mediated delivery system.

Bifunctional cascaded single-atom nanozymes for enhanced photodynamic immunotherapy through dual-depressing PD-L1 and regulating hypoxia

As a promising anti-tumor modality, photodynamic immunotherapy (PDIT) has been applied for the treatment of many solid tumors. However, tumor hypoxic condition and immunosuppressive microenvironment severely limit the treatment outcome of PDIT. Here, we have designed a hairpin tetrahedral DNA nanostructure (H-TDN)-modified bifunctional cascaded Pt single-atom nanozyme (PCFP@H-TDN) with encapsulation of the photosensitizer. The PCFP@H-TDN have dual enzyme-like activities, which can catalyze cascade reactions to generate sufficient O2, reversing the tumor hypoxia and thereby significantly enhancing the anti-tumor effect of PDIT. Meanwhile, H-TDN can not only block the programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) recognition pathway but also target the delivery of PD-L1 antisense oligonucleotides to reduce overall PD-L1 protein expression on the surface of tumor cells, achieving the combination of PD-1/PD-L1 pathway blockade and PD-L1 protein expression silencing. The dual-depressing PD-L1 significantly improves immune checkpoint blockade efficacy. In vivo studies have shown that the constructed PCFP@H-TDN synergistically improved the therapeutic effect of tumors in a multimodal manner through enhancing tumor immunogenicity and upregulating immune cell infiltration at the tumor site. This study provides an efficient nanomedicine to enhance PDIT by depressing PD-L1 and regulating hypoxia.

Unconventional hexagonal open Prussian blue analog structures

Prussian blue analogs (PBAs), as a classical kind of microporous materials, have attracted substantial interests considering their well-defined framework structures, unique physicochemical properties and low cost. However, PBAs typically adopt cubic structure that features small pore size and low specific surface area, which greatly limits their practical applications in various fields ranging from gas adsorption/separation to energy conversion/storage and biomedical treatments. Here we report the facile and general synthesis of unconventional hexagonal open PBA structures. The obtained hexagonal copper hexacyanocobaltate PBA prisms (H-CuCo) demonstrate large pore size and specific surface area of 12.32 Å and 1273 m2 g-1, respectively, well exceeding those (5.48 Å and 443 m2 g-1) of traditional cubic CuCo PBA cubes (C-CuCo). Significantly, H-CuCo exhibits much superior gas uptake capacity over C-CuCo toward carbon dioxide and small hydrocarbon molecules. Mechanism studies reveal that unsaturated Cu sites with planar quadrilateral configurations in H-CuCo enhance the gas adsorption performance.

Coupling Probiotics with CaO2 Nanoparticle-Loaded CoFeCe-LDH Nanosheets to Remodel the Tumor Microenvironment for Precise Chemodynamic Therapy

Chemodynamic therapy (CDT) has become an emerging cancer treatment strategy with advantages of tumor-specificity, high selectivity, and low systemic toxicity. However, it usually suffers from low therapeutic efficacy. This is caused by low hydroxyl radical (·OH) yield arising because of the relatively high pH, overexpressed glutathione, and low H2O2 concentration in the tumor microenvironment (TME). Herein, a probiotic metabolism-initiated pH reduction and H2O2 supply-enhanced CDT strategy is reported to eradicate tumors by generating ·OH, in which Lactobacillus acidophilus is coupled with CoFeCe-layered double hydroxide nanosheets loaded with CaO2 nanoparticles (NPs) as a chemodynamic platform for high-efficiency CDT (CaO2/LDH@L. acidophilus). Owing to the hypoxia tropism of L. acidophilus, CaO2/LDH@L. acidophilus exhibits increased accumulation at tumor sites compared with the CaO2/LDH. The CaO2 NPs loaded on CoFeCe-LDH nanosheets are decomposed into H2O2 in the TME. L. acidophilus metabolite-induced pH reduction (<5.5) and CaO2-mediated in situ H2O2 generation synergistically boost ·OH generation activity of the CoFeCe-LDH nanosheets, effectively damaging cancer cells and ablating tumors with a tumor inhibition rate of 96.4%, 2.32-fold higher than that of CaO2/LDH. This work demonstrates that probiotics can function as a tumor-targeting platform to remodel the TME and amplify ROS generation for highly efficient and precise CDT.

Defect-Engineered Coordination Compound Nanoparticles Based on Prussian Blue Analogues for Surface-Enhanced Raman Spectroscopy

Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for label-free chemical analysis. The emergence of nonmetallic materials as SERS substrates, offering chemical signal enhancements, presents an exciting direction for achieving reproducible and biocompatible SERS, a challenge with traditional metallic substrates. Despite the potential, the realm of nonmetallic SERS substrates, particularly nanoparticles, remains largely untapped. Here, we present defect-engineered coordination compounds (DECCs) based on Prussian blue analogues (PBAs) as a class of nonmetallic nanoparticle-based SERS substrates. We demonstrate the utility and flexibility of the DECC template by incorporating various metal (M) elements into PBAs to synthesize nanoparticles that deliver substantial chemical mechanism (CM)-based enhancements to the Raman signal with a ∼ 108-fold increase. The introduction of the M-PBA-based DECC nanoparticles as a class of SERS substrates represents a pioneering stride, enabling the straightforward and systematic exploration of a library of compounds for SERS-based analysis of a wide range of target molecules, especially biomolecules.

Biomimetic Transparent Slippery Surface for the Locomotion of Photocontrol Droplets and Bubbles

Directed transportation and collection of liquids and bubbles play a vital role in the survival of ecosystems. Among them, the optical response control is widely used in the fields of microfluidic chips and chemical synthesis because of its high remote operation and fast response speed. However, due to poor light transmission, the development direction of traditional near-infrared (NIR) absorbing materials in the field of visualization is limited, and there are few reports of manufacturing an operating platform that can realize the directional movement of droplets/bubbles on a single platform. Here, a transparent photo-responsive PBFS platform is prepared for droplet and bubble manipulation by coating the etched glass substrate with Prussian blue (PB) nanocubes. When near-infrared (NIR) irradiation on the PBFS platform, PB nanocubes trigger heat production by photothermal means, due to the action of Marangoni force, the surface tension on the left and right sides of the droplets and bubbles is not uniform, forming a surface tension gradient, thereby driving the movement of the droplets and bubbles. The control platform has good application potential in the field of microchemical reaction and biomedical engineering and brings new solutions to the field of transparent photothermal materials.

Effect of incorporated transition metals on the adsorption mechanisms of radioactive cesium in Prussian blue analogs

Extensive efforts were made to remove radioactive cesium (137Cs) from the environment, with Prussian blue analogs (PBAs) emerging as highly selective and efficient materials for 137Cs removal. However, limited studies systematically compared Cs+ adsorption across different transition metals in PBA. This study investigates the influence of the choice of transition metal ion (Co, Cu, Fe, Mn, Ni, Zn) on Cs+ adsorption mechanisms and efficiency. PBAs were synthesized and characterized based on their specific surface area, ion exchange capacity, lattice parameter, and defect sites (as indicated by water molecule content). Cs+ adsorption mechanisms varied significantly with transition metals. In CoFe and FeFe PBAs, ion exchange with K+ dominated, while CuFe and MnFe PBAs, with more defect sites primarily used ion exchange between H+ and Cs+. NiFe and ZnFe exhibited enhanced Cs+ adsorption under light irradiation, likely due to their light-absorbing properties facilitating a reduction reaction. The Langmuir adsorption isotherm was applied to model the adsorption behavior, confirming that each performance of PBA depends on the transition metal used. These findings suggest that PBAs with various transition metals can efficiently remove 137Cs under diverse environmental conditions by using distinct adsorption mechanisms.

Catalytic Nanoparticles in Biomedical Applications: Exploiting Advanced Nanozymes for Therapeutics and Diagnostics

Catalytic nanoparticles (CNPs) as heterogeneous catalyst reveals superior activity due to their physio-chemical features, such as high surface-to-volume ratio and unique optical, electric, and magnetic properties. The CNPs, based on their physio-chemical nature, can either increase the reactive oxygen species (ROS) level for tumor and antibacterial therapy or eliminate the ROS for cytoprotection, anti-inflammation, and anti-aging. In addition, the catalytic activity of nanozymes can specifically trigger a specific reaction accompanied by the optical feature change, presenting the feasibility of biosensor and bioimaging applications. Undoubtedly, CNPs play a pivotal role in pushing the evolution of technologies in medical and clinical fields, and advanced strategies and nanomaterials rely on the input of chemical experts to develop. Herein, a systematic and comprehensive review of the challenges and recent development of CNPs for biomedical applications is presented from the viewpoint of advanced nanomaterial with unique catalytic activity and additional functions. Furthermore, the biosafety issue of applying biodegradable and non-biodegradable nanozymes and future perspectives are critically discussed to guide a promising direction in developing span-new nanozymes and more intelligent strategies for overcoming the current clinical limitations.

Near-infrared-responsive Prussian blue nanocages loaded with 5-fluorouracil for combined chemotherapy and photothermal therapy in tumor treatment

Nanodrug delivery systems (NDDS) have been proposed to improve the targeting and bioavailability of chemotherapy drugs. The approach of drug loading via physical adsorption is facile to operate; however, there exists a risk of premature leakage. Coupling the drug molecules with the carrier through chemical reactions can guarantee the stability of the drug delivery process, yet the preparation procedure is relatively intricate. In this research, a kind of Prussian blue nanocage (PB Cage) was fabricated, and the phase change material, 1-pentadecanol, was used as the gating material to solidify 5-fluorouracil (5-FU) inside the nanocage. Upon irradiation with near-infrared (NIR) light, the temperature of the PB Cage can rise rapidly. When the temperature exceeds 43 °C, 1-pentadecanol undergoes a solid-liquid phase transition and subsequently releases 5-FU to inhibit DNA synthesis. Meanwhile, the photothermal therapy (PTT) mediated by the PB Cage is also capable of ablating tumor cells. The NDDS constructed based on PB has achieved the precise release of 5-FU triggered by NIR light, which may avoid side effects on normal tissues. Moreover, the combination of chemotherapy and photothermal therapy can efficaciously suppress the proliferation of tumor cells.

Cobalt doped Prussian blue modified hollow polydopamine for enhanced antibacterial therapy

Give the emergence of drug resistance in bacteria resulting from antibiotic misuse, there is an urgent need for research and application of novel antibacterial approaches. In recent years, nanoparticles (NPs) have garnered significant attention due to their potential to disrupt bacteria cellular structure through loading drugs and special mechanisms, thus rendering them inactive. In this study, the surface of hollow polydopamine (HPDA) NPs was utilized for the growth of Prussian blue (PB), resulting in the formation of HPDA-PB NPs. Incorporation of Co element during the preparation process led to partial doping of PB with Co2+ions. The performance test results demonstrated that the HPDA-PB NPs exhibited superior photothermal conversion efficiency and peroxidase-like activity compared to PB NPs. HPDA-PB NPs have the ability to catalyze the formation of hydroxyl radicals from H2O2in a weakly acidic environment. Due to the tiny PB particles on the surface and the presence of Co2+doping, they have strong broad-spectrum antibacterial properties. Bothin vitroandin vivoevaluations confirm their efficacy against various bacterial strains, particularlyStaphylococcus aureus, and their potential to promote wound healing, making them a promising candidate for advanced wound care and antimicrobial applications.

An Acid-Responsive Iron-Based Nanocomposite for OSCC Treatment

Oral squamous cell carcinoma (OSCC) is the most common type of oral cancer, characterized by invasiveness, local lymph node metastasis, and poor prognosis. Traditional treatment and medications have limitations, making the specific inhibition of OSCC growth, invasion, and metastasis a challenge. The tumor microenvironment exhibits mildly acidity and high concentrations of H2O2, and its exploitation for cancer treatment has been widely researched across various cancers, but research in the oral cancer field is relatively limited. In this study, by loading ultra-small Prussian blue nanoparticles (USPBNPs) into mesoporous calcium-silicate nanoparticles (MCSNs), we developed an acid-responsive iron-based nanocomposite, USPBNPs@MCSNs (UPM), for the OSCC treatment. UPM demonstrated excellent dual enzyme activities, generating toxic ·OH in a mildly acidic environment, effectively killing OSCC cells and producing O2 in a neutral environment to alleviate tissue hypoxia. The results showed that UPM could effectively inhibit the proliferation, migration, and invasion of OSCC cells, as well as the growth of mice solid tumors, without obvious systemic toxicity. The mechanisms may involve UPM inducing ferroptosis of OSCC cells by downregulating the xCT/GPX4/glutathione (GSH) axis, characterized by intracellular iron accumulation, reactive oxygen species accumulation, GSH depletion, lipid peroxidation, and abnormal changes in mitochondrial morphology. Therefore, this study provides empirical support for ferroptosis as an emerging therapeutic target for OSCC and offers a valuable insight for future OSCC treatment.

Critical learning from industrial catalysis for nanocatalytic medicine

Systematical and critical learning from industrial catalysis will bring inspiration for emerging nanocatalytic medicine, but the relevant knowledge is quite limited so far. In this review, we briefly summarize representative catalytic reactions and corresponding catalysts in industry, and then distinguish the similarities and differences in catalytic reactions between industrial and medical applications in support of critical learning, deep understanding, and rational designing of appropriate catalysts and catalytic reactions for various medical applications. Finally, we summarize/outlook the present and potential translation from industrial catalysis to nanocatalytic medicine. This review is expected to display a clear picture of nanocatalytic medicine evolution.

Highly-Efficient Gallium-Interference Tumor Therapy Mediated by Gallium-Enriched Prussian Blue Nanomedicine

Prussian blue (PB)-based nanomedicines constructed from metal ion coordination remain restricted due to their limited therapeutic properties, and their manifold evaluation complexity still needs to be unraveled. Owing to the high similarities of its ionic form to iron (Fe) and the resulting cellular homeostasis disruption performance, physiologically unstable and low-toxicity gallium (Ga) has garnered considerable attention clinically as an anti-carcinogen. Herein, Ga-based nanoparticles (NPs) with diverse Ga contents are fabricated in one step using PB with abundant Fe sites as a substrate for Ga substitution, which aims to overcome the deficiencies of both and develop an effective nanomedicine. A systematic comparison of their physicochemical properties effectively reveals the saturated Ga introduction state during the synthesis process, further identifying the most Ga-enriched PB NPs with a substitution content of >50% as a nanomedicine for subsequent exploration. It is verified that the Ga interference mechanisms mediated by the most Ga-enriched PB NPs are implicated in metabolic disorders, ionic homeostasis disruption, cellular structure dysfunction, apoptosis, autophagy, and target activation of the mammalian target of the rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) pathways. This study provides significant guidance on exploiting clinically approved agents for Ga interference and lays the foundation for the next generation of PB-based theranostic agents.