Magnetic Prussian blue nanoparticles for targeted photothermal therapy under magnetic resonance imaging guidance

Nanomaterials as a Service (NaaS) concept: on-demand protocols for volume synthesis of nanomaterials

Establishing scalable nanomaterials synthesis protocols remains a bottleneck towards their commercialisation and, thus, a topic of intense research and development. Herein, we present an automated machine-learning microfluidic platform capable of synthesising optically active nanomaterials from target spectra originating from prior experience, theorised or published. Implementing unsupervised Bayesian optimisation with Gaussian processes reduces the optimisation time and the need for prior knowledge to initiate the process. Using PTFE tubing and connectors enables facile change in reactor design. Ultimately, the platform substitutes the labour-intensive trial-and-error synthesis and provides a pathway to standardisation and volume synthesis, slowing down the translation and commercialisation of high-quality nanomaterials. As a proof-of-concept, Ag nanoplates and Prussian-blue nanoparticle protocols were optimised and validated for volume production.

From lab to field: Prussian blue frameworks as sustainable cathode materials

Prussian blue and Prussian blue analogues have attracted increasing attention as versatile framework materials with a wide range of applications in catalysis, energy conversion and storage, and biomedical and environmental fields. In terms of energy storage and conversion, Prussian blue-based materials have emerged as suitable candidates of growing interest for the fabrication of batteries and supercapacitors. Their outstanding electrochemical features such as fast charge-discharge rates, high capacity and prolonged cycling life make them favorable for energy storage application. Furthermore, Prussian blue and its analogues as rechargeable battery anodes can advance significantly by the precise control of their structure, morphology, and composition at the nanoscale. Their tunable structural and electronic properties enable the detection of many types of analytes with high sensitivity and specificity, and thus, they are ideal materials for the development of sensors for environmental detection, disease trend monitoring, and industrial safety. Additionally, Prussian blue-based catalysts display excellent photocatalytic performance for the degradation of pollutants and generation of hydrogen. Specifically, their excellent light capturing and charge separation capabilities make them stand out in photocatalytic processes, providing a sustainable option for environmental remediation and renewable energy production. Besides, Prussian blue coatings have been studied particularly for corrosion protection, forming stable and protective layers on metal surfaces, which extend the lifespan of infrastructural materials in harsh environments. Prussian blue and its analogues are highly valuable materials in healthcare fields such as imaging, drug delivery and theranostics because they are biocompatible and their further functionalization is possible. Overall, this review demonstrates that Prussian blue and related framework materials are versatile and capable of addressing many technical challenges in various fields ranging from power generation to healthcare and environmental management.

Photothermal Prussian blue nanoparticles generate potent multi-targeted tumor-specific T cells as an adoptive cell therapy

Prussian blue nanoparticle-based photothermal therapy (PBNP-PTT) is an effective tumor treatment capable of eliciting an antitumor immune response. Motivated by the ability of PBNP-PTT to potentiate endogenous immune responses, we recently demonstrated that PBNP-PTT could be used ex vivo to generate tumor-specific T cells against glioblastoma (GBM) cell lines as an adoptive T cell therapy (ATCT). In this study, we further developed this promising T cell development platform. First, we assessed the phenotype and function of T cells generated using PBNP-PTT. We observed that PBNP-PTT facilitated CD8+ T cell expansion from healthy donor PBMCs that secreted IFNγ and TNFα and upregulated CD107a in response to engagement with target U87 cells, suggesting specific antitumor T cell activation and degranulation. Further, CD8+ effector and effector memory T cell populations significantly expanded after co-culture with U87 cells, consistent with tumor-specific effector responses. In orthotopically implanted U87 GBM tumors in vivo, PBNP-PTT-derived T cells effectively reduced U87 tumor growth and generated long-term survival in >80% of tumor-bearing mice by Day 100, compared to 0% of mice treated with PBS, non-specific T cells, or T cells expanded from lysed U87 cells, demonstrating an enhanced antitumor efficacy of this ATCT platform. Finally, we tested the generalizability of our approach by generating T cells targeting medulloblastoma (D556), breast cancer (MDA-MB-231), neuroblastoma (SH-SY5Y), and acute monocytic leukemia (THP-1) cell lines. The resulting T cells secreted IFNγ and exerted increased tumor-specific cytolytic function relative to controls, demonstrating the versatility of PBNP-PTT in generating tumor-specific T cells for ATCT.

Nanosized Prussian blue and its analogs for bioimaging and cancer theranostics

Prussian blue (PB) nanoparticles (NPs) and Prussian blue analogs (PBAs) can form metal-organic frameworks through the programmable coordination of ferrous ions with cyanide. PB and PBAs represent a burgeoning class of hybrid functional nano-systems with a wide-ranging application spectrum encompassing biomedicine, cancer diagnosis, and therapy. A comprehensive overview of recent advancements is crucial for gaining insights for future research. In this context, we reviewed the synthesis techniques and surface modification strategies employed to tailor the dimensions, morphology, and attributes of PB NPs. Subsequently, we explored advanced biomedical utilities of PB NPs, encompassing photoacoustic imaging, magnetic resonance imaging, ultrasound (US) imaging, and multimodal imaging. In particular, the application of PB NPs-mediated photothermal therapy, photodynamic therapy, and chemodynamic therapy to cancer treatment was reviewed. Based on the literature, we envision an evolving trajectory wherein the future of Prussian blue-driven biological applications converge into an integrated theranostic platform, seamlessly amalgamating bioimaging and cancer therapy. STATEMENT OF SIGNIFICANCE: Prussian blue, an FDA-approved coordinative pigment with a centuries-long legacy, has paved the way for Prussian blue nanoparticles (PB NPs), renowned for their remarkable biocompatibility and biosafety. These PB NPs have found their niche in biomedicine, playing crucial roles in both diagnostics and therapeutic applications. The comprehensive review goes beyond PB NP-based cancer therapy. Alongside in-depth coverage of PB NP synthesis and surface modifications, the review delves into their cutting-edge applications in the realm of biomedical imaging, encompassing techniques such as photoacoustic imaging, magnetic resonance imaging, ultrasound imaging, and multimodal imaging.

Smart Nanozymes for Cancer Therapy: The Next Frontier in Oncology

Nanomaterials that mimic the catalytic activity of natural enzymes in the complex biological environment of the human body are called nanozymes. Recently, nanozyme systems have been reported with diagnostic, imaging, and/or therapeutic capabilities. Smart nanozymes strategically exploit the tumor microenvironment (TME) by the in situ generation of reactive species or by the modulation of the TME itself to result in effective cancer therapy. This topical review focuses on such smart nanozymes for cancer diagnosis, and therapy modalities with enhanced therapeutic effects. The dominant factors that guide the rational design and synthesis of nanozymes for cancer therapy include an understanding of the dynamic TME, structure-activity relationships, surface chemistry for imparting selectivity, and site-specific therapy, and stimulus-responsive modulation of nanozyme activity. This article presents a comprehensive analysis of the subject including the diverse catalytic mechanisms of different types of nanozyme systems, an overview of the TME, cancer diagnosis, and synergistic cancer therapies. The strategic application of nanozymes in cancer treatment can well be a game changer in future oncology. Moreover, recent developments may pave the way for the deployment of nanozyme therapy into other complex healthcare challenges, such as genetic diseases, immune disorders, and ageing.

Imaging application of an MMP2-sensitive tumor-targeted prussian blue fluorescent nanoprobe

In recent years, the application of nanoimaging technology on standardize tumor diagnosis has become a new research hotspot, especially nanoprobes. Our research group has synthesized a kind of nanocarrier, mPEG2000-GPLGIAGQ-DSPE, which has the characteristic of matrix metalloproteinase-2 (MMP2) sensitive ability in tumor microenvironment. Meanwhile, the encapsulation method is adopted to prepare MMP2-sensitive tumor-targeted prussian blue fluorescent nanoprobe with mPEG2000-GPLGIAGQ-DSPE as the carrier. On the one hand, this novel nanoprobe not only can effectively improve the solubility of prussian blue, but is non-toxic and safe for cells. On the other hand, octapeptide (GPLGIAGQ) in mPEG2000-GPLGIAGQ-DSPE nanocarrier can specifically respond to MMP2 in tumor cells to release prussian blue, and achieve targeted intelligent imaging of tumor cells.

Uncovering the Fate and Risks of Intravenously Injected Prussian Blue Nanoparticles in mice by an Integrated Methodology of Toxicology, Pharmacokinetics, Proteomics, and Metabolomics

BACKGROUND

Prussian blue (PB) nanoparticles (NPs) have been intensively investigated for medical applications, but an in-depth toxicological investigation of PB NPs has not been implemented. In the present study, a comprehensive investigation of the fate and risks of PB NPs after intravenous administration was carried out by using a mouse model and an integrated methodology of pharmacokinetics, toxicology, proteomics, and metabolomics.

RESULTS

General toxicological studies demonstrated that intravenous administration of PB NPs at 5 or 10 mg/kg could not induce obvious toxicity in mice, while mice treated with a relatively high dose of PB NPs at 20 mg/kg exhibited loss of appetite and weight decrease in the first two days postinjection. Pharmacokinetic studies revealed that intravenously administered PB NPs (20 mg/kg) underwent fast clearance from blood, highly accumulated in the liver and lungs of mice, and finally cleared from tissues. By further integrated proteomics and metabolomics analysis, we found that protein expression and metabolite levels changed significantly in the liver and lungs of mice due to the high accumulation of PB NPs, leading to slight inflammatory responses and intracellular oxidative stress.

CONCLUSIONS

Collectively, our integrated experimental data imply that the high accumulation of PB NPs may cause potential risks to the liver and lungs of mice, which will provide detailed references and guidance for further clinical application of PB NPs in the future.

Tumor immunosuppression relief via acidity modulation combined PD-L1 siRNA for enhanced immunotherapy

The efficacy of immune checkpoint therapy is limited by the immunosuppressive tumor microenvironment (TME), and lactate, the most universal component of TME, has been rediscovered that plays important roles in the regulation of metabolic pathways, angiogenesis, and immunosuppression. Here, a therapeutic strategy of acidity modulation combined with programmed death ligand-1 (PD-L1) siRNA (siPD-L1) is proposed to synergistically enhance tumor immunotherapy. The lactate oxidase (LOx) is encapsulated into the hollow Prussian blue (HPB) nanoparticles (NPs) prepared by hydrochloric acid etching followed by the modification with polyethyleneimine (PEI) and polyethylene glycol (PEG) via sulfur bonds (HPB-S-PP@LOx), siPD-L1 is loaded via electrostatic adsorption to obtain HPB-S-PP@LOx/siPD-L1. The obtained co-delivery NPs can accumulate in tumor tissue with stable systemic circulation, and simultaneous release of LOx and siPD-L1 in intracellular high glutathione (GSH) environment after uptake by tumor cells without being destroyed by lysosome. Moreover, LOx can catalyze the decomposition of lactate in the hypoxic tumor tissue with the aid of oxygen release by the HPB-S-PP nano-vector. The results show that the acidic TME regulation via lactate consumption can improve the immunosuppressive TME, including revitalizing the exhausted CD8⁺ T cells and decreasing the proportion of immunosuppressive Tregs, and synergistically elevating the therapeutic effect of PD1/PD-L1 blockade therapy via siPD-L1. This work provides a novel insight for tumor immunotherapy and explores a promising therapy for triple-negative breast cancer.

Hybrid Au-star@Prussian blue for high-performance towards bimodal imaging and photothermal treatment

In recent years, branched or star-shaped Au nanostructures composed of core and protruding arms have attracted much attention due to their unique optical properties and morphology. As the clinically adapted nanoagent, prussian blue (PB) has recently gained widespread attention in cancer theranostics with potential applications in magnetic resonance (MR) imaging. In this article, we propose a hybrid star gold nanostructure（Au-star@PB）as a novel theranostic agent for T1-weighted magnetic resonance imaging (MRI)/ photoacoustic imaging（PAI） and photothermal therapy (PTT) of tumors. Importantly, the Au-star@PB nanoparticles function as effective MRI/PA contrast agents in vivo by increasing T1-weighted MR/PAI signal intensity and as effective PTT agents in vivo by decreasing the tumor volume in MCF-7 tumor bearing BALB / c mouse model as well as in vitro by lessening tumor cells growth rate. Interestingly, we found the main photothermal effect of Au-star@PB is derived from Au-star, but not PB. In summary, the hybrid structure of Au-star@PB NPs with good biological safety, significant photostability, dual imaging capability, and high therapeutic efficiency, might offer a novel avenue for the future diagnosis and treatment of cancer.

Metal-organic framework-based nanoplatform enhance fibroblast activity to treat periodontitis

After periodontal tissue injury, reconstruct soft tissue sealing around the tooth surface is of fundamental importance to treat periodontitis. Among multiple cell types, fibroblast plays a central role in reestablishing functional periodontium. To enhance fibroblast activity, a novel metal-organic framework-based nanoplatform is fabricated using mesoporous Prussian blue (MPB) nanoparticles to load baicalein (BA), named MPB-BA. Drug release test displayed sustained BA release of MPB-BA. Cell proliferation, transwell migration and wound healing tests revealed accelerated fibroblast proliferation and migration for the established MPB-BA nanoplatform. Moreover, vinculin immunofluorescence staining, western blot and quantitative real-time PCR analysis showed up-regulated vinculin protein and integrin α5 and integrin β1 gene expressions for MPB-BA, suggesting improved cell adhesion. In addition, hematoxylin and eosin (H&E) and Masson trichromatic staining suggested superior anti-inflammatory and collagen fiber reconstruction effects for MPB-BA in a rat experimental periodontitis model in vivo. Our study may provide a promising strategy for the treatment of periodontitis.

Interstitial Photothermal Therapy Generates Durable Treatment Responses in Neuroblastoma

Photothermal therapy (PTT) represents a promising modality for tumor control typically using infrared light-responsive nanoparticles illuminated by a wavelength-matched external laser. However, due to the constraints of light penetration, PTT is generally restricted to superficially accessible tumors. With the goal of extending the benefits of PTT to all tumor settings, interstitial PTT (I-PTT) is evaluated by the photothermal activation of intratumorally administered Prussian blue nanoparticles with a laser fiber positioned interstitially within the tumor. This interstitial fiber, which is fitted with a terminal diffuser, distributes light within the tumor microenvironment from the "inside-out" as compared to from the "outside-in" traditionally observed during superficially administered PTT (S-PTT). I-PTT improves the heating efficiency and heat distribution within a target treatment area compared to S-PTT. Additionally, I-PTT generates increased cytotoxicity and thermal damage at equivalent thermal doses, and elicits immunogenic cell death at lower thermal doses in targeted neuroblastoma tumor cells compared to S-PTT. In vivo, I-PTT induces significantly higher long-term tumor regression, lower rates of tumor recurrence, and improved long-term survival in multiple syngeneic murine models of neuroblastoma. This study highlights the significantly enhanced therapeutic benefit of I-PTT compared to traditional S-PTT as a promising treatment modality for solid tumors.

Nanotechnology-Based Diagnostic and Therapeutic Strategies for Neuroblastoma

Neuroblastoma (NB), as the most common extracranial solid tumor in childhood, is one of the critical culprits affecting children's health. Given the heterogeneity and invisibility of NB tumors, the existing diagnostic and therapeutic approaches are inadequate and ineffective in early screening and prognostic improvement. With the rapid innovation and development of nanotechnology, nanomedicines have attracted widespread attention in the field of oncology research for their excellent physiological and chemical properties. In this review, we first explored the current common obstacles in the diagnosis and treatment of NB. Then we comprehensively summarized the advancements in nanotechnology-based multimodal synergistic diagnosis and treatment of NB and elucidate the underlying mechanisms. In addition, a discussion of the pending challenges in biocompatibility and toxicity of nanomedicine was conducted. Finally, we described the development and application status of nanomaterials against some of the recognized targets in the field of NB research, and pointed out prospects for nanomedicine-based precision diagnosis and therapy of NB.

Photothermal-enhanced peroxidase-like activity of CDs/PBNPs for the detection of Fe3+ and cholesterol in serum samples

Carbon dots/Prussian blue nanoparticles (CDs/PBNPs) with fluorescence (FL) performance and peroxidase-like activity are synthesized by a simple two-step method. The FL of CDs/PBNPs can be effectively quenched by Fe³⁺. Fe³⁺ can accelerate the peroxidase-like activity of CDs/PBNPs. More excitingly, the peroxidase-like activity of CDs/PBNPs could be further enhanced due to the influence of the photothermal effect. Based on the FL property and enhanced peroxidase-like activity, a cascade strategy is proposed for detection of Fe³⁺ and free cholesterol. CD/PBNPs act as FL probe for detection of Fe³⁺. The enhanced peroxidase-like activity of CDs/PBNPs can also be used as colorimetric probe for the detection of free cholesterol. The detection ranges of Fe³⁺ and free cholesterol are 4-128 μM and 2-39 μM, and the corresponding limit of detections are 2.0 μM and 1.63 μM, respectively. The proposed strategy has been verified by the feasibility determination of Fe³⁺ and free cholesterol, suggesting its potential in the prediction of disease.

Construction multifunctional nanozyme for synergistic catalytic therapy and phototherapy based on controllable performance

Advances in nanozyme involve an efficient catalytic process, which has demonstrated great potential in tumor therapy. The key to improving catalytic therapy is to solve the limitation of the tumor microenvironment on Fenton reaction. In this work, Prussian blue nanoparticles doped with different rare earth ions (Yb³⁺, Gd³⁺, Tm³⁺) were screened to perform synergistic of photothermalandcatalytictumortherapy. The optimized catalytic performance can be further enhanced through photothermal effect to maximize the Fenton reaction to solve the limitation of the tumor microenvironment. Yb-PB, with the optimal photothermal and catalytic performance, was screened out. In order to avoid the scavenging effect of glutathione (GSH) on ·OH in tumor cells and the reaction with a bit H₂O₂ in normal cells, GSH targeted polydopamine (PDA) was wrapped on the surface of Yb-PB to obtain Yb-PB@PDA. It was found that enough hydroxyl radicals (·OH) can be generated even if at high GSH concentration and the NIR irradiation can help produce more ·OH. Cell fluorescence imaging (FOI) and in vivo magnetic resonance imaging (MRI) experiments showed the potential application in FOI/MRI dual-mode imaging guided therapy. In vivo anti-tumor experiments showed that Yb-PB@PDA has a satisfactory anti-cancer effect through the combined effect of catalytic/photothermal therapy. Thus, a multifunctional nanozyme for tumor therapy is constructed.

Multifunctional Biodegradable Prussian Blue Analogue for Synergetic Photothermal/Photodynamic/Chemodynamic Therapy and Intrinsic Tumor Metastasis Inhibition

To date, various Prussian blue analogues (PBAs) have been prepared for biomedical applications due to their unique structural advantages. However, the safety and effectiveness of tumor treatment still need further exploration. This contribution reports a facile synthesis of PBA with superior tumor synergetic therapeutic effects and a detailed mechanistic evaluation of their intrinsic tumor metastasis inhibition activity. The as-synthesized PBA has a uniform cube structure with a diameter of approximately 220 nm and shows high near-infrared light (NIR) photoreactivity, photothermal conversion efficiency (41.44%), and photodynamic effect. Additionally, PBA could lead to a chemodynamic effect, which is caused by the Fenton reaction and ferroptosis. The combined therapy strategy of PBA exhibits notable tumor ablation properties due to photothermal therapy (PTT)/photodynamic therapy (PDT)/chemodynamic therapy (CDT) effects without obvious toxicity in vivo. The PBA has also shown potential as a contrast agent for magnetic resonance imaging (MRI) and photoacoustic (PA) imaging. More importantly, careful investigations reveal that PBA displays excellent biodegradation and anti-metastasis properties. Further exploration of the PBA implies that its underlying mechanism of intrinsic tumor metastasis inhibition activity can be attributed to the modulation of epithelial-mesenchymal transition (EMT) expression. The considerable potential exhibited by the as-synthesized PBA makes it an ideal candidate as a synergetic therapeutic agent for tumor treatment.

The recent progress on metal-organic frameworks for phototherapy

Some infectious or malignant diseases such as cancers are seriously threatening the health of human beings all over the world. The commonly used antibiotic therapy cannot effectively treat these diseases within a short time, and also bring about adverse effects such as drug resistance and immune system damage during long-term systemic treatment. Phototherapy is an emerging antibiotic-free strategy to treat these diseases. Upon light irradiation, phototherapeutic agents can generate cytotoxic reactive oxygen species (ROS) or induce a temperature increase, which leads to the death of targeted cells. These two kinds of killing strategies are referred to as photodynamic therapy (PDT) and photothermal therapy (PTT), respectively. So far, many photo-responsive agents have been developed. Among them, the metal-organic framework (MOF) is becoming one of the most promising photo-responsive materials because its structure and chemical compositions can be easily modulated to achieve specific functions. MOFs can have intrinsic photodynamic or photothermal ability under the rational design of MOF construction, or serve as the carrier of therapeutic agents, owing to its tunable porosity. MOFs also provide feasibility for various combined therapies and targeting methods, which improves the efficiency of phototherapy. In this review, we firstly investigated the principles of phototherapy, and comprehensively summarized recent advances of MOF in PDT, PTT and synergistic therapy, from construction to modification. We expect that our demonstration will shed light on the future development of this field, and bring it one step closer to clinical trials.

Mechanically Strong, Liquid-Resistant Photothermal Bioplastic Constructed from Cellulose and Metal-Organic Framework for Light-Driven Mechanical Motion

The development of photothermal materials with a high light-to-heat conversion capability is essential for the utilization of clean solar energy. In this work, we demonstrate the use of a novel and sustainable concept involving cellulose liquefaction, rapid gelation, in situ synthesis and hot-press drying to convert cellulose and metal-organic framework (Prussian blue) into a stable photothermal bioplastic that can harvest sunlight and convert it into mechanical motion. As expected, the obtained Prussian blue@cellulose bioplastic (PCBP) can effectively absorb sunlight and the surface can be heated up to 70.3 °C under one sun irradiation (100 mW cm-2). As a demonstration of the practicality of PCBP, it was successfully used to drive a Stirling engine motion. Meanwhile, hot-pressing promotes the densification of the structure of PCBP and, therefore, improves the resistance to the penetration of water/non-aqueous liquids. Moreover, PCBP shows good mechanical properties and thermal stability. Given the excellent photothermal performance and environmentally friendly features of photothermal conversion bioplastic, we envisage this sustainable plastic film could play important roles toward diversified applications: a photothermal layer for thermoelectric generator, agricultural films for soil mulching and photothermal antibacterial activity, among others.

Stimuli-Responsive Iron Oxide Nanotheranostics: A Versatile and Powerful Approach for Cancer Therapy

Recent advancements in unravelling elements of cancer biology involved in disease progression and treatment resistance have highlighted the need for a holistic approach to effectively tackle cancer. Stimuli-responsive nanotheranostics based on iron oxide nanoparticles are an emerging class of versatile nanomedicines with powerful capabilities to "seek, sense, and attack" multiple components of solid tumors. In this work, the rationale for using iron oxide nanoparticles and the basic physical principles that impact their function in biomedical applications are reviewed. Subsequently, recent advances in the integration of iron oxide nanoparticles with various stimulus mechanisms to facilitate the development of stimuli-responsive nanotheranostics for application in cancer therapy are summarized. The integration of an iron oxide core with various surface coating mechanisms results in the generation of hybrid nanoconstructs with capabilities to codeliver a wide variety of highly potent anticancer therapeutics and immune modulators. Finally, emerging future directions and considerations for their clinical translation are touched upon.

Fluorescence imaging-guided cancer photothermal therapy using polydopamine and graphene quantum dot-capped Prussian blue nanocubes

In recent years, imaging-guided photothermal tumor ablation has attracted intense research interest as one of the most exciting strategies for cancer treatment. Herein, we prepared polydopamine and graphene quantum dot-capped Prussian blue nanocubes (PB@PDA@GQDs, PBPGs) with high photothermal conversion efficiency and excellent fluorescence performance for imaging-guided cancer treatment. Transmission electron microscopy (TEM), UV-vis absorption spectroscopy (UV-vis), fluorescence spectroscopy, and X-ray photoelectron spectroscopy (XPS) were employed to characterize their morphology and structures. The photothermal conversion efficiency and therapeutic effect were evaluated in vitro and in vivo. Results revealed that this nanoagent had excellent biocompatibility and enhanced the photothermal effect compared to blue nanocubes (PBs) and polydopamine-capped Prussian blue nanocubes (PB@PDA, PBPs). Therefore, our study may open a new path for the production of PB-based nanocomposites as theranostic nanoagents for imaging-guided photothermal cancer treatment.

Designing heterostructured core@satellite Prussian Blue Analogue@Au–Ag nanoparticles: Effect on the magnetic properties and catalytic activity

Prussian Blue Analogue@Au–Ag nanoparticles: Effect on the magnetic properties and catalytic activity.

The Application of Prussian Blue Nanoparticles in Tumor Diagnosis and Treatment

Prussian blue nanoparticles (PBNPs) have attracted increasing research interest in immunosensors, bioimaging, drug delivery, and application as therapeutic agents due to their large internal pore volume, tunable size, easy synthesis and surface modification, good thermal stability, and favorable biocompatibility. This review first outlines the effect of tumor markers using PBNPs-based immunosensors which have a sandwich-type architecture and competitive-type structure. Metal ion doped PBNPs which were used as T1-weight magnetic resonance and photoacoustic imaging agents to improve image quality and surface modified PBNPs which were used as drug carriers to decrease side effects via passive or active targeting to tumor sites are also summarized. Moreover, the PBNPs with high photothermal efficiency and excellent catalase-like activity were promising for photothermal therapy and O2 self-supplied photodynamic therapy of tumors. Hence, PBNPs-based multimodal imaging-guided combinational tumor therapies (such as chemo, photothermal, and photodynamic therapies) were finally reviewed. This review aims to inspire broad interest in the rational design and application of PBNPs for detecting and treating tumors in clinical research.

Single-step formulation of levodopa-based nanotheranostics - strategy for ultra-sensitive high longitudinal relaxivity MRI guided switchable therapeutics

Nanotheranostics (combined diagnosis and therapy) is emerging as an integral part of future therapeutic strategies. However, the development and fabrication of a nanotheranostic module involves multistep processes and always faces formulation challenges. The complexity involved in its multi-step formulations hinders its reproducible industrial production and clinical translation. Therefore, a facile synthesis of multifunctional nanotheranostics is critical to its translational success. In this report, we have developed a one-pot facile strategy to prepare a MRI-visible photothermal theranostic switchable module (T-SWITCH). These nanoparticles are synthesized through polymerization of levodopa together with the reduction of KMnO4 in the presence of silk sericin for the formation of manganese dioxide particles within the T-SWITCH. The synthesized T-SWITCH showed a uniform size distribution of around 95.77 nm and high longitudinal relaxivity coefficient (r1) of up to 61.94 mM-1 s-1. The reported r1 of the T-SWITCH is exceedingly higher than that of any other previously reported manganese-based contrast agents with first-rate in vitro and in vivo contrast enhancement capability. The T-SWITCH can be activated to switch its therapeutic mode using near-infrared (NIR) light. It exhibited strong excitable absorption in the safer and biological NIR window between 650 and 900 nm. We have validated the significant anti-cancer therapeutic efficacy of T-SWITCH both in vitro and in vivo through switchable photothermal therapy.

Nanozyme amplification mediated on-demand multiplex lateral flow immunoassay with dual-readout and broadened detection range

Development of sensitive, facile and rapid biosensors is important for widespread applications. Nanozymes can be ideal signal donors for constructing dual-readout lateral flow immunoassays (LFIA) because they are an excellent class of optical reporters. Herein, a magnetic prussian blue nanozyme (MPBN) mediated dual-readout on-demand multiplex lateral flow immunoassay (MLFIA) was established by employing ractopamine (RAC) and clenbuterol (CLE) as the model analytes. The MPBN was synthesized through in-suit shell-growing and introduced as a bifunctional signal tag owing to their darker original color and peroxidase-like activity. Based on the catalytic signal created by catalyzing oxidation of chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) and colorimetric signal generated by tag's original color, improved precision and broadened detection range were acquired by implementing a dual-readout strategy. And a two-fold increase in the detection range could fulfill different limit requirements of the same target in various regions. The obtained recoveries from 84.01% to 119.94% indicating the repeatability and reliability of the proposed method. This method provides an attractive platform for the detection of a same target with different detection limits, which possesses a considerable potential in monitoring of other targets.

Finely tuned Prussian blue-based nanoparticles and their application in disease treatment

The Prussian blue (PB) based nanostructure is a mixed-valence coordination network with excellent biosafety, remarkable photothermal effect and multiple enzyme-mimicking behaviours. Compared with other nanomaterials, PB-based nanoparticles (NPs) exhibit several unparalleled advantages in biomedical applications. This review begins with the chemical composition and physicochemical properties of PB-based NPs. The tuning strategies of PB-based NPs and their biomedical properties are systemically demonstrated. Afterwards, the biomedical applications of PB-based NPs are comprehensively recounted, mainly focusing on treatment of tumors, bacterial infection and inflammatory diseases. Finally, the challenges and future prospects of PB-based NPs and their application in disease treatment are discussed.

Remotely tunable microfluidic platform driven by nanomaterial-mediated on-demand photothermal pumping

The requirement of on-demand microfluidic pumps and instrument-free readout methods remains a major challenge for the development of microfluidics. Herein, a new type of microfluidic platform, an on-demand photothermal microfluidic pumping platform, has been developed using an on-chip nanomaterial-mediated photothermal effect as novel and remotely tunable microfluidic driving force. The photothermal microfluidic pumping performance can be adjusted remotely by tuning the irradiation parameters, without changing on-chip parameters or replacing enzymes or other reagents. In contrast to graphene oxide, Prussian blue nanoparticles with higher photothermal conversion efficiency were used as the model photothermal agent to demonstrate the proof of concept. The on-chip pumping distance is linearly correlated with both the irradiation time and the nanomaterial concentration. The applications of photothermal microfluidic pumping have been demonstrated in multiplexed on-chip transport of substances, such as gold nanoparticles, and visual quantitative bar-chart detection of cancer biomarkers without using specialized instruments. Upon contact-free irradiation using a laser pointer, a strong on-chip nanomaterial-mediated photothermal effect can serve as a robust and remotely tunable microfluidic pump in a PMMA/PDMS hybrid bar-chart chip to drive ink bars in a visual quantitative readout fashion. This is the first report on a photothermal microfluidic pumping platform, which has great potential for various microfluidic applications.

Prussian blue nanocubes as a multimodal contrast agent for image-guided stem cell therapy of the spinal cord

Translation of stem cell therapies to treat injuries and diseases of the spinal cord is hindered by lack of real-time monitoring techniques to guide regenerative therapies intra- and postoperatively. Thus, we developed an ultrasound (US), photoacoustic (PA), and magnetic resonance (MR) imaging approach augmented with Prussian blue nanocubes (PBNCs) to guide stem cell injections intraoperatively and monitor stem cell therapies in the spinal cord postoperatively. Per the clinical procedure, a multi-level laminectomy was performed in rats ex vivo, and PBNC-labeled stem cells were injected directly into the spinal cord while US/PA images were acquired. US/PA/MR images were also acquired post-surgery. Several features of the imaging approach were demonstrated including detection of low stem cell concentrations, real-time needle guidance and feedback on stem cell delivery, and good agreement between US/PA/MR images. These benefits span intra- and postoperative environments to support future development of this imaging tool.

Prussian blue nanoparticles: synthesis, surface modification, and biomedical applications

Prussian blue nanoparticles (PBNPs) are a nanomaterial that presents unique properties and an excellent biocompatibility. They can be synthesized in mild conditions and can be derivatized with polymers and/or biomolecules. PBNPs are used in biomedicine as therapy and diagnostic agents. In biomedical imaging, PBNPs constitute contrast agents in photoacoustic and magnetic resonance imaging (MRI). They are a good adsorbent to be used as antidotes for poisoning with cesium and/or thallium ions. Moreover, the ability to convert energy into heat makes them useful photothermal agents (PAs) in photothermal therapy (PTT) or as nonantibiotic substances with antibacterial properties. Finally, PBNPs can be both reduced to Prussian white and oxidized to Prussian green. A large window of redox potential exists between reduction and oxidation, which result in the enzyme-like characteristics of these NPs.

Multifunctional HNT@Fe3O4@PPy@DOX Nanoplatform for Effective Chemo-Photothermal Combination Therapy of Breast Cancer with MR Imaging

Multifunctional nanoparticles for imaging and treatment in cancer are getting more and more attention recently. Herein, halloysite nanotubes (HNTs), natural clay nanotubes, are designed as multifunctional nanoplatform for targeted delivering photothermal therapy agents and chemotherapeutic drugs. Fe₃O₄ was anchored on the outer surfaces of HNTs and then doxorubicin (DOX) was loaded on the nanotubes. Afterward, a layer of polypyrrole (PPy), as photothermal agent, was wrapped on the tubes. The nanoplatform of HNT@Fe₃O₄@PPy@DOX can be guided to tumor tissue by an external magnetic field, and then performs chemo-photothermal combined therapy by 808 nm laser irradiation. HNT@Fe₃O₄@PPy@DOX shows the ability of T₂-weighted magnetic resonance imaging, which could be considered as a promising application in magnetic targeting tumor therapy. In vitro and in vivo experiments demonstrate that HNTs nanoplatform has good biocompatibility and produces a strong antitumor effect trigged by near-infrared laser irradiation. The novel chemo-photothermal therapy nanoplatform based on HNTs may be developed as a multifunctional nanoparticle for imaging and therapy in breast cancer.

Polydopamine Coated PB-MnO2 Nanoparticles as an Oxygen Generator Nanosystem for Imaging-Guided Single-NIR-Laser Triggered Synergistic Photodynamic/Photothermal Therapy

Exploring a combined phototherapeutic strategy to overcome the limitations of a single mode therapy and inducing high anticancer efficiency is highly promising for precision cancer nanomedicine. However, a single-wavelength laser activates dual photothermal/photodynamic therapy (PTT/PDT) treatment is still a formidable challenge. Herein, we strategically design and fabricate a multifunctional theranostic nanosystem based on chlorin e6-functionalized polydopamine (PDA) coated prussian blue/manganese dioxide nanoparticles (PB-MnO₂@PDA-Ce6 NPs). Interestingly, the obtained PB-MnO₂@PDA NPs not only offer an effective delivery system for Ce6 but also provide strong optical absorption in the near-infrared range, endowing high antitumor efficacy of PTT. More importantly, the as-prepared PB-MnO₂@PDA-Ce6 nanoagents exhibit an effective oxygen generation, superior reactive oxygen species (ROS), and outstanding photothermal conversion ability to greatly improve PTT and PDT treatments. As a result, both in vitro and in vivo treatments guided by MR imaging on liver cancer cells reveal the complete cell/tumor eradication under a single wavelength of 660 nm laser irradiation, implying the simultaneous synergistic PDT/PTT effects triggered by PB-MnO₂@PDA-Ce6 nanoplatform, which are much higher than individual treatment. Taken together, our phototherapeutic nanoagents exhibit an excellent therapeutic performance, which may act as a nanoplatform to find safe and clinically translatable routes to accelerate cancer therapeutics.

Photomagnetic Prussian blue nanocubes: Synthesis, characterization, and biomedical applications

Nanoparticles play an important role in biomedicine. We have developed a method for size-controlled synthesis of photomagnetic Prussian blue nanocubes (PBNCs) using superparamagnetic iron oxide nanoparticles (SPIONs) as precursors. The developed PBNCs have magnetic and optical properties desired in many biomedical diagnostic and therapeutic applications. Specifically, the size-tunable photomagnetic PBNCs exhibit high magnetic saturation, strong optical absorption with a peak at approximately 700 nm, and superior photostability. Our studies demonstrate that PBNCs can be used as MRI and photoacoustic imaging contrast agents in vivo. We also showed the utility of PBNCs for labeling and magnetic manipulation of cells. Dual magnetic and optical properties, together with excellent biocompatibility, render PBNCs an attractive contrast agent for both diagnostic and therapeutic applications. The use SPIONs as precursors for PBNCs provides flexibility and allows researchers to design theranostic agents according to required particle size, optical, and magnetic properties.

Synergic effect of doxorubicin release and two-photon irradiation of Mn2+-doped Prussian blue nanoparticles on cancer therapy

We demonstrate here that Mn²⁺-doped Prussian blue nanoparticles of ca. 55 nm loaded with doxorubicin may be used as efficient therapeutic agents for combined photothermal and chemo-therapy of cancer cells with a synergic effect under two photon irradiation.

Mn²⁺-doped Prussian blue nanoparticles loaded with doxorubicin present high efficiency for combined photothermal and chemotherapy of cancer cells with a synergic effect under two-photon irradiation.

Zn2+ Doped Ultrasmall Prussian Blue Nanotheranostic Agent for Breast Cancer Photothermal Therapy under MR Imaging Guidance

Prussian blue nanoprobes are widely studied and applied in tumor photothermal therapy (PTT) and magnetic resonance imaging (MRI), due to their low toxicity and excellent in vivo performance. However, the sizes of hitherto reported Prussian blue nanoprobes are generally larger than 50 nm, which greatly influence cell phagocytosis, in vivo circulation, and biodistribution. In this work, a novel method of doping zinc ions is used to control the size of Prussian blue nanoprobes. Consequently, the performances of the nanoprobes in PTT and MRI are both significantly improved. The results show that the minimum size of Prussian blue nanoprobes achieved by doping 10% zinc ions (abbreviated as SPBZn(10%)) is 3.8 ± 0.90 nm, and the maximum specific absorption coefficient, photothermal conversion efficiency, and longitudinal relaxation rates are 1.78 L g^-1 cm^-1 , 47.33%, and 18.40 mm^-1 s^-1 , respectively. In addition, the SPBZn(10%) nanoprobes provide excellent PTT efficacy on 4T1 tumor cells (killing rate: 90.3%) and breast cancer model (tumor inhibition rate: 69.4%). Toxicological experiment results show that the SPBZn(n%) nanoprobes exhibit no obvious in vitro cytotoxicity and they can be used safely in mice at doses below 100 mg kg^-1 . Therefore, SPBZn(10%) nanoprobes can potentially be used for effective cancer theranostics.

Superparamagnetic iron oxide nanoparticulate system: synthesis, targeting, drug delivery and therapy in cancer

Cancer is a global epidemic and is considered a leading cause of death. Various cancer treatments such as chemotherapy, surgery, and radiotherapy are available for the cure but those are generally associated with poor long-term survival rates. Consequently, more advanced and selective methods that have better outcomes, fewer side effects, and high efficacies are highly in demand. Among these is the use of superparamagnetic iron oxide nanoparticles (SPIONs) which act as an innovative kit for battling cancer. Low cost, magnetic properties and toxicity properties enable SPIONs to be widely utilized in biomedical applications. For example, magnetite and maghemite (Fe3O4 and γ-Fe2O3) exhibit superparamagnetic properties and are widely used in drug delivery, diagnosis, and therapy. These materials are termed SPIONs when their size is smaller than 20 nm. This review article aims to provide a brief introduction on SPIONs, focusing on their fundamental magnetism and biological applications. The quality and surface chemistry of SPIONs are crucial in biomedical applications; therefore an in-depth survey of synthetic approaches and surface modifications of SPIONs is provided along with their biological applications such as targeting, site-specific drug delivery and therapy.

Spatiotemporally Controlled Multiplexed Photothermal Microfluidic Pumping under Monitoring of On-Chip Thermal Imaging

Intelligent contactless microfluidic pumping strategies have been increasingly desirable for operation of lab-on-a-chip devices. Herein, we present a photothermal microfluidic pumping strategy for on-chip multiplexed cargo transport in a contactless and spatiotemporally controllable fashion based on the application of near-infrared laser-driven photothermal effect in microfluidic paper-based devices (μPDs). Graphene oxide (GO)-doped thermoresponsive poly(N-isopropylacrylamide)-acrylamide hydrogels served as the photothermally responsive cargo reservoirs on the μPDs. In response to remote contactless irradiation by an 808 nm laser, on-chip phase transition of the composite hydrogels was actuated in a switchlike manner as a result of the photothermal effect of GO, enabling robust on-chip pumping of cargoes from the hydrogels to predefined arrays of reaction zones. The thermal imaging technique was employed to monitor the on-chip photothermal pumping process. The microfluidic pumping performance can be spatiotemporally controlled in a quantitative way by remotely tuning the laser power, irradiation time, and GO concentration. The pumping strategy was exemplified by FeCl₃ and horseradish peroxidase as the model cargoes to implement on-chip Prussian blue- and 3,3',5,5'-tetramethylbenzidine-based colorimetric reactions, respectively. Furthermore, multiplexed on-demand microfluidic pumping was achieved by flexibly adjusting the irradiation pathway and the microfluidic pattern. The new microfluidic pumping strategy shows great promise for diverse microfluidic applications due to its flexibility, high integratability into lab-on-a-chip devices, and contactless and spatiotemporal controllability.

Light-activatable Chlorin e6 (Ce6)-imbedded erythrocyte membrane vesicles camouflaged Prussian blue nanoparticles for synergistic photothermal and photodynamic therapies of cancer

Multiple therapeutic modalities, such as photodynamic (PDT) and photothermal (PTT) therapies, have been jointly applied to produce a synergistic effect for tumor eradication based on the hyperthermia and generation of reactive oxygen species (ROS) mediated by photoactive agents. Effective delivery of highly efficient photosensitizers and photothermal agents is the key for combination of PDT/PTT. Herein, we propose a strategy to functionalize Prussian blue (PB) nanoparticles (NPs) with Chlorin e6 (Ce6)-imbedded erythrocyte membrane vesicles. This nanoplatform can address the major issues of these two capable photoactive agents, such as limited biocompatibility, lack of functional chemical groups, and poor bioavailability due to rapid blood clearance or self-aggregation. Specifically, PB NPs were packaged within Ce6-imbedded erythrocyte membrane vesicles, named as PB@RBC/Ce6 NPs, to take advantage of both biological functions of natural erythrocyte membranes and the unique physicochemical properties of synthetic nanoagents. Compared to bare PB NPs or free Ce6, PB@RBC/Ce6 NPs exhibited considerably enhanced cellular uptake and accumulation in tumoral tissues. Moreover, the PB@RBC/Ce6 NP-mediated PDT/PTT combination therapies produced a notable effect in boosting the necrosis and late apoptosis of tumor cells in vitro, and further showed a synergistic therapeutic effect against an orthotopic tumor model in vivo.

Biomedical Applications of Hyaluronic Acid-Based Nanomaterials in Hyperthermic Cancer Therapy

Hyaluronic acid (HA) is a non-sulfated polysaccharide polymer with the properties of biodegradability, biocompatibility, and non-toxicity. Additionally, HA specifically binds to certain receptors that are over-expressed in cancer cells. To maximize the effect of drug delivery and cancer treatment, diverse types of nanomaterials have been developed. HA-based nanomaterials, including micelles, polymersomes, hydrogels, and nanoparticles, play a critical role in efficient drug delivery and cancer treatment. Hyperthermic cancer treatment using HA-based nanomaterials has attracted attention as an efficient cancer treatment approach. In this paper, the biomedical applications of HA-based nanomaterials in hyperthermic cancer treatment and combined therapies are summarized. HA-based nanomaterials may become a representative platform in hyperthermic cancer treatment.

Integrated Hydrogel Platform for Programmed Antitumor Therapy Based on Near Infrared-Triggered Hyperthermia and Vascular Disruption

Complete tumor regression is a great challenge faced by single therapy of near-infrared (NIR)-triggered hyperthermia or vascular disrupting agents. An injectable nanocomposite (NC) hydrogel is rationally designed for combined anticancer therapy based on NIR-triggered hyperthermia and vascular disruption. The NC hydrogel, codelivered with Prussian blue (PB) nanoparticles and combretastatin A4 (CA4), has good shear-thinning, self-recovery, and excellent photothermal properties. Because of the remarkable tumor-site retention and sustained release of CA4 (about 10% over 12 days), the NC hydrogel has a tumor suppression rate of 99.6%. The programmed combinational therapy conveys the concept of "attack + guard", where PB-based NIR irradiation imposes intensive attack on most of cancer cells, and CA4 serves as a guard against the tumor growth by cutting off the energy supply. Moreover, the biosafety and eco-friendliness of the hydrogel platform pave the way toward clinical applications.

Correction to: Magnetic-core@dual-functional-shell nanocomposites with peroxidase mimicking properties for use in colorimetric and electrochemical sensing of hydrogen peroxide

A self-sacrificing catalytic method is described for the preparation of magnetic core/dual-functional-shell nanocomposites composed of magnetite, gold and Prussian blue (type Fe₃O₄@Au-PB). Two reaction pathways are integrated. The first involves chemical dissolution of Fe₃O₄ (the self-sacrificing step) by acid to release ferrous ions which then reacts with hexacyanoferrate(IV) to generate PB in the proximity of the magntic nanoparticles (MNPs). The second involves the reduction of tetrachloroaurate by hydroxylamine to generate gold under the catalytic effect of the MNPs. At the end, the MNP@Au-PB nanocomposite is formed. This method exploits both the chemical reactivity and catalytic effect of the MNPs in a single step. The multi-function material was applied (a) in an optical assay for H₂O₂; (b) in an amperometric assay for H₂O₂; (c) in an enzymatic choline assay using immobilized choline oxidase. The limit of electrochemical detection of H₂O₂ (at a potential as low as 50 mV) is 1.1 μM which is comparable or better than most analogous methods. The sensors display superior performance compared to the use of conventional core@single-shell (MNP@Au-PB) nanomaterials. Graphical abstract A self-sacrificing catalytic method is described to prepare magnetic core/dual-functional-shell nanocomposites composed of magnetic nanoparticle, gold and Prussian blue (type MNP@Au-PB). The nanocomposites worded well as candidates to develop colorimetric and electrochemical sensors of H₂O₂ with superior performance to analogues.