High-efficiency freezing-induced loading of inorganic nanoparticles and proteins into micron- and submicron-sized porous particles

We demonstrate a novel approach to the controlled loading of inorganic nanoparticles and proteins into submicron- and micron-sized porous particles. The approach is based on freezing/thawing cycles, which lead to high loading densities. The process was tested for the inclusion of Au, magnetite nanoparticles, and bovine serum albumin in biocompatible vaterite carriers of micron and submicron sizes. The amounts of loaded nanoparticles or substances were adjusted by the number of freezing/thawing cycles. Our method afforded at least a three times higher loading of magnetite nanoparticles and a four times higher loading of protein for micron vaterite particles, in comparison with conventional methods such as adsorption and coprecipitation. The capsules loaded with magnetite nanoparticles by the freezing-induced loading method moved faster in a magnetic field gradient than did the capsules loaded by adsorption or coprecipitation. Our approach allows the preparation of multicomponent nanocomposite materials with designed properties such as remote control (e.g. via the application of an electromagnetic or acoustic field) and cargo unloading. Such materials could be used as multimodal contrast agents, drug delivery systems, and sensors

Experimental pressure-temperature phase diagram of boron: resolving the long-standing enigma

Boron, discovered as an element in 1808 and produced in pure form in 1909, has still remained the last elemental material, having stable natural isotopes, with the ground state crystal phase to be unknown. It has been a subject of long-standing controversy, if α-B or β-B is the thermodynamically stable phase at ambient pressure and temperature. In the present work this enigma has been resolved based on the α-B-to- β-B phase boundary line which we experimentally established in the pressure interval of ∼4 GPa to 8 GPa and linearly extrapolated down to ambient pressure. In a series of high pressure high temperature experiments we synthesised single crystals of the three boron phases (α-B, β-B, and γ-B) and provided evidence of higher thermodynamic stability of α-B. Our work opens a way for reproducible synthesis of α-boron, an optically transparent direct band gap semiconductor with very high hardness, thermal and chemical stability

Hybrid inorganic-organic capsules for efficient intracellular delivery of novel siRNAs against influenza A (H1N1) virus infection

This work was supported by ARUK project grant 21210 ‘Sustained and Controllable Local Delivery of Anti-inflammatory Therapeutics with Nanoengineered Microcapsules’. The work was also supported in part by Russian Foundation of Basic Research grants No. 16-33-50153 mol_nr, No. 16-33-00966 mol_a, Russian Science Foundation grant No. 15-15-00170 and Russian Governmental Program ‘‘Nauka’’, No. 1.1658.2016, 4002

Decoupling the shape parameter to assess gold nanorod uptake by mammalian cells

The impact of nanoparticles (NPs) upon biological systems can be fundamentally associated with their physicochemical parameters. A further often-stated tenet is the importance of NP shape on rates of endocytosis. However, given the convoluted parameters concerning the NP–cell interaction, it is experimentally challenging to attribute any findings to shape alone. Herein we demonstrate that shape, below a certain limit, which is specific to nanomedicine, is not important for the endocytosis of spherocylinders by either epithelial or macrophage cells in vitro. Through a systematic approach, we reshaped a single batch of gold nanorods into different aspect ratios resulting in near-spheres and studied their cytotoxicity, (pro-)inflammatory status, and endocytosis/exocytosis. It was found that on a length scale of ∼10–90 nm and at aspect ratios less than 5, NP shape has little impact upon their entry into either macrophages or epithelial cells. Conversely, nanorods with an aspect ratio above 5 were preferentially endocytosed by epithelial cells, whereas there was a lack of shape dependent uptake following exposure to macrophages in vitro. These findings have implications both in the understanding of nanoparticle reshaping mechanisms, as well as in the future rational design of nanomaterials for biomedical applications

Permeability adjustment of polyelectrolyte micro-and nanocapsules by laser irradiation

Laser radiation was used for permeability increase up to destroy of polyelectrolyte capsules. Silver and gold nanoparticles was synthesized and incorporated into capsule shells to attain the sensitivity of microcapsules to laser radiation. Lasers of different power and wavelength were used. The sensitivity of nanocomposite shell to laser radiation can be controlled by nanoparticle shape, content and distribution into the shell

Calcium carbonate particle synthesis in a confined and dynamically thinning layer on a spin-coater – in situ deposition for cell adhesion

We have designed a new method for the in situ synthesis of CaCO3 particles via spin-coating while simultaneously controlling their distribution on the surface. CaCO3 is synthesized by simultaneously adding CaCl2 and Na2CO3 solutions to a rotating surface on a spin-coater. During the transient liquid film evaporation on the spin-coater, as the film layer progressively thins, the CaCO3 particles nucleate and grow while confined within that thinning layer on the spin-coater. The evaporation of the volatile component increases the global concentration of solids, resulting in the deposition of precipitates (CaCO3 particles). The growth rate, particle size, and coverage were theoretically and experimentally analyzed by adjusting the process parameters, initial salt concentrations, rotational speed, and post-deposition treatment. Experimental findings indicated that increasing the rotational speed resulted in formation of smaller particle sizes, while the concentration of the precursors directly influenced the average diameter of the particles. Raman spectroscopy analysis demonstrated that vaterite particles synthesized from lower salt concentrations exhibited a more intense signal than those synthesized from higher salt concentrations. Furthermore, higher salt concentrations led to increased particle coverage, while higher rotational speeds resulted in decreased particle coverage on the substrate. We explored the potential of such coatings in biomedicine and tissue engineering by seeding MC3T3-E1 cells on the CaCO3 particle-coated glass substrates. Surfaces functionalized with CaCO3 particles exhibited enhanced cell proliferation and adhesion