Achieving Ultrasmall Prussian Blue Nanoparticles as High-Performance Biomedical Agents with Multifunctions

Abstract

Prussian blue nanoparticles (PBNPs), which belong to the iron-based metal−organic frameworks, are important biomedical agents. Reducing the size of PBNPs can bring improved functional properties, but unfortunately, has been a long-standing challenge. Herein, sub-5 nm ultrasmall PBNPs (USPBNPs) were successfully synthesized by using ethanol/water mixture as the solvent and polyvinyl pyrrolidone (PVP) as the surface capping agent. Adjusting the ethanol/water ratio is not only able to control the nucleation time and size of PBNPs but also tune the conformation of PVP molecules so as to prevent interparticle attachment and enlargement. At an ethanol/water ratio of 3:1, highly stable USPBNPs with a size of ∼3.4 nm were synthesized. Due to their large specific surface area, they demonstrated high peroxidase-like and catalase-like activities, which outperform PBNPs synthesized by a conventional method. In addition, they also showed a high longitudinal relaxation rate (r 1 ) of 1.3 mM −1 S −1 , suggesting their potential to be used as T 1 MRI agent.

Prussian Blue: A Nanozyme with Versatile Catalytic Properties

“…As indicated, the size of such nanoparticles is usually reported to be over 10 nm [ 7 ]. Recently, ultrasmall PBNPs ~3.4 nm in diameter have been prepared by using an ethanol/water mixture as the solvent and polyvinyl pyrrolidone (PVP) as the surface capping agent [ 19 ]. The stability of the PB or PBA nanoparticles plays a key role in determining the suitability for potential utilization.…”

“…The catalytic activity of nanozymes exhibits a size-dependent manner since, for the same volume, nanozymes with a small size expose more active sites. According to this, ultrasmall PBNPs have been demonstrated to possess the highest POD-like activity [ 19 ]. The catalytic activity of these nanoparticles was one order of magnitude higher than that of PBNPs obtained by the conventional methods.…”

“…Similar to the observed POD-like activity, the CAT-like activity is also size-dependent. Ultrasmall PBNPs tend to be more effective and exhibit higher enzyme-like catalytic activity than PBNPs of higher size [ 19 ]. The initial catalytic rate of the ultrasmall nanoparticles was 5.3 mg L −1 min −1 compared to 0.77 mg L −1 min −1 of PBNPs [ 31 ].…”

Prussian Blue and Its Analogs as Novel Nanostructured Antibacterial Materials

“…The amphiphilic properties of the polymer also allow the redispersion of the PBNPs in different solvents. PVP-assisted synthesis also allows also the production of ultrasmall PBNPs, with a size of 3.4 nm [32], and grants very good control over the cubic shape of the particles. As Gu and colleagues pointed out in a recent review [33], many other polymers can be used as stabilizing agents in the synthesis of PBNPs, leading to tunable surface properties of the nanomaterials.…”

A Novel Bionic Catalyst-Mediated Drug Delivery System for Enhanced Sonodynamic Therapy

“…Catalase can catalyze the breakdown of hydrogen peroxide and thus improve the tumor microenvironment (Xu et al, 2019;Zinger et al, 2019). Notwithstanding, naturally-occurring catalysts are costly and highly challenging to be successfully delivered within tumor microenvironments (Qin et al, 2018;Lei et al, 2019;Qin et al, 2020). Consequently, current research efforts are focusing on developing artificial catalysts bearing the same potentials of naturally-orrurring catalase.…”