In-situ growth of micro-cubic Prussian blue–TiO2 composite film as a highly sensitive H2O2 sensor by aerosol co-deposition approach

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.

Highly dispersed silver imbedded into TiN submicrospheres for electrochemical detecting of hydrogen peroxide

We report the fabrication of silver nanoparticles evenly imbedded into TiN submicrospheres via one-pot solvothermal reaction and subsequent nitridation for electrochemical detecting of hydrogen peroxide. The precursor of TiO₂ submicrospheres and high dispersion of silver nanoparticles are regulated by the alcoholysis of tetrabutyl titanate and reducibility of enol in vitamin C. The ion nitriding promoted the conductivity and micro-nano porous structure on the surface of TiN submicrospheres, which increase the dispersity of silver nanoparticles and make contributions to avoid aggregations. More importantly, the electrochemical response of Ag-TiN submicrospheres to H₂O₂ was remarkably enhanced due to the co-effects of Ag and N-doping. It provides a superior sensing performance for electrochemical detection of hydrogen peroxide at − 0.3 V with a high sensitivity of 33.25 μA mmol L⁻¹ cm⁻², wide linear range of 0.05–2100 μM and low detection limit of 7.7 nM. The fabricated sensor also reliably applied in detection of H₂O₂ in milk samples with good reproducibility, repeatability and storage stability.

Simultaneous biosensing of catechol and hydroquinone via a truncated cube-shaped Au/PBA nanocomposite

A simultaneous testing of the trace catechol (CC) and hydroquinone (HQ) was achieved via an ultrasensitive phenolic biosensor constructed by the truncated cube-shaped gold/Prussian blue analogue (Au/PBA) nanocomposites. A facile charge-assembly strategy was developed to drive the successive mutual attractions for the crystallization among [Fe(CN)₆]^3-, Co²⁺, and [AuCl₄]^- reactants, benefiting the in-situ growth of Au nanoparticles on all faces of the PBA truncated nanocubes. On account of this special architecture, numerous 10 nm Au particles can rapidly gather the electrons from the enzyme reaction to a PBA crystal due to their high conductivity, and then the current signals will be significantly magnified through the reversible redox of the PBA. Using this nanomaterial, the as-prepared biosensor has shown an extreme wide linear range (CC: 0.2-550 µM, HQ: 1-550 µM) and an ultralow detection limit (CC: 0.06 ± 0.001 µM, HQ: 0.3 ± 0.007 µM) for the independent detections of CC and HQ. More importantly, when the two targets coexist, this biosensor can simultaneously exhibit the obvious and accurate responses of CC and HQ at the different potentials (0.17 V for CC and 0.07 V for HQ) with the high sensitivities and rare mutually interferences.

Prussian blue nanoparticles: Synthesis, surface modification, and application in cancer treatment

This review outlines recently developed Prussian blue nanoparticle (PB NPs)-based multimodal imaging-guided chemo-photothermal strategies for cancer diagnosis and treatment in order to provide insight into the future of the field. The primary limitation of existing therapeutics is the lack of selectivity in drug delivery: they target healthy and cancerous cells alike. In this paper, we provide a thorough review of diverse synthetic and surface engineering techniques for PB NP fabrication. We have elucidated the various targeting approaches employed to deliver the therapeutic and imaging ligands into the tumor area, and outlined methods for enhancement of the tumor ablative ability of the NPS, including several important combinatorial approaches. In addition, we have summarized different in vitro and in vivo effects of PB NP-based therapies used to overcome both systemic and tumor-associated local barriers. An important new approach - PB NP-based immune drug delivery, which is an exciting and promising strategy to overcome cancer resistance and tumor recurrence - has been discussed. Finally, we have discussed the current understanding of the toxicological effects of PB NPs and PB NP-based therapeutics. We conclude that PB NP-based multimodal imaging-guided chemo-photothermal therapy offers new treatment strategies to overcome current hurdles in cancer diagnosis and treatment.

Current control by electrode coatings formed by polymerization of dopamine at prussian blue-modified electrodes

Electrode coating with polydopamine (PDA) is fast becoming a popular surface modification technique. In this study we report the investigation of the use of PDA as electrode coatings with Prussian blue (PB) as an electrode material model. The PB layer was galvanostatically deposited at an Au electrode, followed by PDA coating with the assistance of ammonium persulfate as an oxidant. The thickness of PDA coatings was measured to be ∼60 nm. Electrochemical characterization of the PDA-coated PB electrode revealed that the PDA coatings could stabilize the PB at neutral pH and allow the permeation of hydrogen peroxide (H2O2). Moreover, the PDA coatings were found to effectively exclude the common interfering compounds such as cysteine, ascorbic acid and uric acid, and exhibit selective electrocatalysis towards the electroreduction of H2O2. Accordingly, the PDA-coated PB electrode was applied for determination of H2O2 released from live cells.

Fabrication of a novel electrochemical sensing platform based on a core–shell nano-structured/molecularly imprinted polymer for sensitive and selective determination of ephedrine

A simple methodology was used to develop a novel sensor based on a core–shell/molecularly imprinted polymer (MIP) for the determination of ephedrine.

A highly sensitive electrochemical sensor for simultaneous determination of hydroquinone and bisphenol A based on the ultrafine Pd nanoparticle@TiO2 functionalized SiC

A titanium dioxide-silicon carbide nanohybrid (TiO2-SiC) with enhanced electrochemical performance was successfully prepared through a facile generic in situ growth strategy. Monodispersed ultrafine palladium nanoparticles (Pd NPs) with a uniform size of ∼2.3 nm were successfully obtained on the TiO2-SiC surface via a chemical reduction method. The Pd-loaded TiO2-SiC nanohybrid (Pd@TiO2-SiC) was characterized by transmission electron microscopy and X-ray diffractometry. A method for the simultaneous electrochemical determination of hydroquinone (HQ) and bisphenol A (BPA) using a Pd@TiO2-SiC nanocomposite-modified glassy carbon electrode was established. Utilizing the favorable properties of Pd NPs, the Pd@TiO2-SiC nanohybrid-modified glassy carbon electrode exhibited electrochemical performance superior to those of TiO2-SiC and SiC. Differential pulse voltammetry was successfully used to simultaneously quantify HQ and BPA within the concentration range of 0.01-200 μM under optimal conditions. The detection limits (S/N=3) of the Pd@TiO2-SiC nanohybrid electrode for HQ and BPA were 5.5 and 4.3 nM, respectively. The selectivity of the electrochemical sensor was improved by introducing 10% ethanol to the buffer medium. The practical application of the modified electrode was demonstrated by the simultaneous detection of HQ and BPA in tap water and wastewater samples. The simple and straightforward strategy presented in this paper are important for the facile fabrication of ultrafine metal NPs@metal oxide-SiC hybrids with high electrochemical performance and catalytic activity.