Mitigation of Quantum Dot Cytotoxicity by Microencapsulation

When CdSe/ZnS-polyethyleneimine (PEI) quantum dots (QDs) are microencapsulated in polymeric microcapsules, human fibroblasts are protected from acute cytotoxic effects. Differences in cellular morphology, uptake, and viability were assessed after treatment with either microencapsulated or unencapsulated dots. Specifically, QDs contained in microcapsules terminated with polyethylene glycol (PEG) mitigate contact with and uptake by cells, thus providing a tool to retain particle luminescence for applications such as extracellular sensing and imaging. The microcapsule serves as the “first line of defense” for containing the QDs. This enables the individual QD coating to be designed primarily to enhance the function of the biosensor

Comparative study of cytotoxicity of ferromagnetic nanoparticles and magnetitecontaining polyelectrolyte microcapsules

The work was supported by Ministry of Education and Science of the Russian Federation as part of the State task for National Research Mordovia State University, project No. 2952 and the Government of the Russian Federation (grant №14.Z50.31.0004 to support scientific research projects implemented under the supervision of leading scientists

Free-standing polyelectrolyte membranes made of chitosan and alginate

Free-standing films have increasing applications in the biomedical field as drug delivery systems for wound healing and tissue engineering. Here, we prepared free-standing membranes by the layer-by-layer assembly of chitosan and alginate, two widely used biomaterials. Our aim was to produce a thick membrane and to study the permeation of model drugs and the adhesion of muscle cells. We first defined the optimal growth conditions in terms of pH and alginate concentration. The membranes could be easily detached from polystyrene or polypropylene substrate without any postprocessing step. The dry thickness was varied over a large range from 4 to 35 μm. A 2-fold swelling was observed by confocal microscopy when they were immersed in PBS. In addition, we quantified the permeation of model drugs (fluorescent dextrans) through the free-standing membrane, which depended on the dextran molecular weight. Finally, we showed that myoblast cells exhibited a preferential adhesion on the alginate-ending membrane as compared to the chitosan-ending membrane or to the substrate side.This work was financially supported by Foundation for Science and Technology (FCT) through the Scholarship SFRH/BD/64601/2009 granted to S.G.C. C.M. is indebted to Grenoble INP for financial support via a postdoctoral fellowship. This work was supported by the European Commission (FP7 Program) via a European Research Council starting grant (BIOMIM, GA 259370 to C.P.). C.P. is also grateful to Institut Universitaire de France and to Grenoble Institute of Technology for financial support. We thank Isabelle Paintrand for her technical help with the confocal apparatus and Patrick Chaudouet for his help with SEM imaging

Spectrum of spatial frequency of terahertz vortex Bessel beams formed using phase plates with spiral zones

Abstract. This paper presents the first numerical and experimental investigation into the angular spectrum of terahertz Bessel beam with orbital angular momentum generated by a phase plate with spiral zones. The plate was exposed to a Gaussian beam of the Novosibirsk free electron laser. The Bessel beam formed was passed through a collecting lens. The distribution of the intensity of radiation with a wavelength of 141 microns before and after the focusing lens was recorded by a microbolometer array, which was moved along the optical axis by a motorized translation stage. The experimentally measured intensity distributions over the beam cross section recorded along the optical axis are in good agreement with numerical calculations. Keywords: terahertz Bessel beam, free electron laser, phase plate with spiral zones Citation: Zhabin V.N., Volodkin B.O., Knyazev B.A., Mitkov M.S., Pavelyev V.S., Choporova Yu.Yu. Spectrum of spatial frequency of terahertz vortex Bessel beams formed using phase plates with spiral zones

Polyelectrolyte microcapsule arrays: preparation and biomedical applications

In the need of development of versatile and flexible platforms for sensing and other biomedical applications, micro- and nanostructured particle arrays attract strong scientific interest. In this review we focus on fabrication of arrays of polyelectrolyte layer-by-layer assembled microcapsules and bio-related applications of such arrays. A cargo encapsulated in the microcapsules can be released on demand, thus opening perspectives for biosensing, diagnostics, controlled drug delivery, and tissue engineering. Here, we also consider a new composite systemmicrocapsules embedded into polymeric filmboth components are made by the LbL technique. Fabrication approaches and perspectives in the preparation and in the use of the microcapsule arrays are addressed