The development of multifunctional drug delivery systems combining two or more nanoparticle-mediated therapies for efficient cancer treatment is highly desired. To face this challenge, a photothermally active polydopamine (PDA) nanoparticle-based platform was designed for the loading of chemotherapeutic drug and targeting of cancer cells. PDA spheres were first functionalized with polyamidoamine (PAMAM) dendrimers followed by the conjugation with polyethylene glycol (PEG) moieties and folic acid (FA) targeting ligand. The anticancer drug doxorubicin (DOX) was then absorbed on the particle surface. We performed the physico-chemical characterization of this versatile material and we assessed further its possible application in chemo- and photothermal therapy using liver cancer cell model. These nanoparticles exhibited high near-infrared photothermal conversion efficacy and allowed for loading of the drug, which upon release in specifically targeted cancer cells suppressed their growth. Using cell proliferation, membrane damage, apoptosis, and oxidative stress assays we demonstrated high performance of this nanosystem in cancer cell death induction, providing a novel promising approach for cancer therapy.

Marine sponges were among the first multicellular organisms on our planet and have survived to this day thanks to their unique mechanisms of chemical defense and the specific design of their skeletons, which have been optimized over millions of years of evolution to effectively inhabit the aquatic environment. In this work, we carried out studies to elucidate the nature and nanostructural organization of three-dimensional skeletal microfibers of the giant marine demosponge Ianthella basta, the body of which is a micro-reticular, durable structure that determines the ideal filtration function of this organism. For the first time, using the battery of analytical tools including three-dimensional micro—X-ray Fluorescence (3D-µXRF), X-ray diffraction (XRD), infra-red (FTIR), Raman and Near Edge X-ray Fine Structure (NEXAFS) spectroscopy, we have shown that biomineral calcite is responsible for nano-tuning the skeletal fibers of this sponge species. This is the first report on the presence of a calcitic mineral phase in representatives of verongiid sponges which belong to the class Demospongiae. Our experimental data suggest a possible role for structural amino polysaccharide chitin as a template for calcification. Our study suggests further experiments to elucidate both the origin of calcium carbonate inside the skeleton of this sponge and the mechanisms of biomineralization in the surface layers of chitin microfibers saturated with bromotyrosines, which have effective antimicrobial properties and are responsible for the chemical defense of this organism. The discovery of the calcified phase in the chitinous template of I. basta skeleton is expected to broaden the knowledge in biomineralization science where the calcium carbonate is regarded as a valuable material for applications in biomedicine, environmental science, and even in civil engineering.

It has been long known that the physical encapsulation of oleic acid-capped iron oxide nanoparticles (OA–IONPs) with the cetyltrimethylammonium (CTA⁺) surfactant induces the formation of spherical iron oxide nanoparticle clusters (IONPCs). However, the behavior and functional properties of IONPCs in chemical reactions have been largely neglected and are still not well-understood. Herein, we report an unconventional ligand-exchange function of IONPCs activated when dispersed in an ethyl acetate/acetate buffer system. The ligand exchange can successfully transform hydrophobic OA–IONP building blocks of IONPCs into highly hydrophilic, acetate-capped iron oxide nanoparticles (Ac–IONPs). More importantly, we demonstrate that the addition of silica precursors (tetraethyl orthosilicate and 3-aminopropyltriethoxysilane) to the acetate/oleate ligand-exchange reaction of the IONPs induces the disassembly of the IONPCs into monodispersed iron oxide–acetate–silica core–shell–shell (IONPs@acetate@SiO₂) nanoparticles. Our observations evidence that the formation of IONPs@acetate@SiO₂ nanoparticles is initiated by a unique micellar fusion mechanism between the Pickering-type emulsions of IONPCs and nanoemulsions of silica precursors formed under ethyl acetate buffered conditions. A dynamic rearrangement of the CTA⁺–oleate bilayer on the IONPC surfaces is proposed to be responsible for the templating process of the silica shells around the individual IONPs. In comparison to previously reported methods in the literature, our work provides a much more detailed experimental evidence of the silica-coating mechanism in a nanoemulsion system. Overall, ethyl acetate is proven to be a very efficient agent for an effortless preparation of monodispersed IONPs@acetate@SiO₂ and hydrophilic Ac–IONPs from IONPCs.

A designed assembly of particles at liquid interfaces offers many advantages for development of materials, and can be performed by various means. Electric fields provide a flexible method for structuring particles on drops, utilizing electrohydrodynamic circulation flows, and dielectrophoretic and electrophoretic interactions. In addition to the properties of the applied electric field, the manipulation of particles often depends on the intrinsic properties of the particles to be assembled. Here, we present an easy approach for producing polystyrene microparticles with different electrical properties. These particles are used for investigations into electric field-guided particle assembly in the bulk and on surfaces of oil droplets. By sulfonating polystyrene particles, we produce a set of particles with a range of dielectric constants and electrical conductivities, related to the sulfonation reaction time. The paper presents diverse particle behavior driven by electric fields, including particle assembly at different droplet locations, particle chaining, and the formation of ribbon-like structures with anisotropic properties.