Deposition Of Charged Nanoparticles Research Articles

Patterns of Charged Gold Nanoparticles for Cell Adhesion Control

Event Abstract Back to Event Patterns of Charged Gold Nanoparticles for Cell Adhesion Control Florian Emmerich1* and Christiane Thielemann1 1 University of Applied Sciences Aschaffenburg, BioMEMS-Lab, Germany In the past two decades, numerous approaches for locally controlled cell outgrowth on Multi-Electrode-Arrays (MEA) have been made. Generally, the adhesion promoting patterning approaches can be subdivided into two classes: chemical structuring [1] and topographic structuring [2]. With our new approach we try to combine both ideas by using charged nano-particles. The shape of the nanoparticles acts as topographic element, whereas net charge on the particles generates a chemical attraction. In a similar approach for neuronal cells [3], nanoparticles were structured in a complex process, starting with a pattern generation by nano-imprint-lithography (NIL) to prepare the surface for silanization. After a lift-off process, charged gold nanoparticles have been immobilized on the patterned, silanized surface, where the charge of the particles could be adjusted with further treatment. Our process is faster and easier to implement and has the advantage of mask-free structure writing on the MEA chip without adjustment steps. Deposition of charged nanoparticles on small areas by electric fields is referred to as nanoxerography. A dielectric material with additional charge carriers, called electret, generates an electric field to attract nano-particles. The charges can be injected using either by an electron microscope, an atomic force microscope (AFM) or by electric micro contact printing. We used an Asylum Research MPF 3D AFM to locally inject charges and visualize them with Kelvin-Probe-Force-Microscopy (KPFM). Substrates were conventional cover slips (170 µm thickness) with 100 nm Indium-Tin-Oxide (ITO) as conducting top layer. On top of ITO we applied in a spin-coating process 30 nm Poly(methyl methacrylate) (PMMA) as electret layer. In a second step we used charged gold nanoparticles solved in isopropanol with a mean diameter of 10 nm. The deposition on the charged patterns, followed a protocol described by Palleau et al. [4]. Briefly, we attached 50 µl of the nano-particle solution for t = 10 s, placed the whole sample for t = 50 s in a beaker with ethanol, rinsed the sample thoroughly and dried it with nitrogen. The results of the charging and deposition process are shown in Figure 1: For proof of principle, the human embryonic kidney 293 (HEK) cell line was used for the cell patterning experiments. HEK-293 cells were seeded onto the nano-particle processed samples with no further treatment. Cells were cultured in DMEM/Ham's F-12 (1:1) supplemented with 10 % FCS and 1 % penicillin-streptomycin. The following ten days after seeding, the adhesion and proliferation of the cells was analyzed by inverse optical microscopy. Structures of nanoparticles on PMMA were prepared according to our new approach. HEK cells were seeded on this patterns and our preliminary results indicate a preferred adhesion of the HEK cells on nanoparticle structured areas. We presented a nanoparticle-based method for selectively increasing the adhesion properties of HEK-cells, which is fast, scalable and easy to implement. The next step will be the integration onto a MEA chip surface coated with PMMA, which will allow us to write mask-less cell patterns for cardiac myocytes and neurons on MEA chips. Keywords: nanoparticle, Cell guiding, Kelvin-Probe-Force-Microscopy, nano-xerography Conference: MEA Meeting 2016 | 10th International Meeting on Substrate-Integrated Electrode Arrays, Reutlingen, Germany, 28 Jun - 1 Jul, 2016. Presentation Type: Poster Presentation Topic: MEA Meeting 2016 Citation: Emmerich F and Thielemann C (2016). Patterns of Charged Gold Nanoparticles for Cell Adhesion Control. Front. Neurosci. Conference Abstract: MEA Meeting 2016 | 10th International Meeting on Substrate-Integrated Electrode Arrays. doi: 10.3389/conf.fnins.2016.93.00087 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 22 Jun 2016; Published Online: 24 Jun 2016. * Correspondence: Dr. Florian Emmerich, University of Applied Sciences Aschaffenburg, BioMEMS-Lab, Aschaffenburg, Germany, florian.emmerich@h-ab.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Florian Emmerich Christiane Thielemann Google Florian Emmerich Christiane Thielemann Google Scholar Florian Emmerich Christiane Thielemann PubMed Florian Emmerich Christiane Thielemann Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Deposition of charged nano-particles in the human airways including effects from cartilaginous rings

This paper presents a numerical study of the deposition of spherical charged nano-particles caused by convection, Brownian diffusion and electrostatics in a pipe with a cartilaginous ring structure. The model describes the deposition of charged particles in the different generations of the tracheobronchial tree of the human lung. The upper airways are characterized by a certain wall structure called cartilaginous rings which modify the particle deposition when compared to an airway with a smooth wall. The problem is defined by solving Naver-Stokes equations in combination with a convective-diffusion equation and Gauss law for electrostatics. Three non- dimensional parameters describe the problem, the Peclet number Pe = 2ūa/D , the Reynolds number Re = ūa/v and an electrostatic parameter α=α2c0q2/(4e0κT) . Here U is the mean velocity, a the pipe radius and D the diffusion coefficient due to Brownian motion given by D=κTCu/3πμd , where Cu is the Cunningham-factor Cu=1+λ/d(2.34+1.05exp(-0.39d/λ)) Here d is the particle diameter and λ the mean free path of the air molecules. Results are provided for generations G4-G16 of the human airways. The electrostatic parameter is varied to model different concentrations and charge numbers.

Growth of gold/zinc sulphide multilayer films using layer-by-layer assembly of colloidal nanoparticles

Fabrication of multilayer thin films through layer-by-layer (lbl) deposition of charged nanoparticles on tin-doped indium oxide (ITO) coated and uncoated glass substrates are reported. The thin films were constructed by alternately dipping a substrate into a colloidal suspension of chitosan capped zinc sulphide (ZnS) nanoparticles (∼30 nm) and citrate stabilized colloidal gold (Au) nanoparticles (∼20 nm) leading to electrostatic interactions between the oppositely charged nanoparticle layers. Thin films consisting of up to 200 deposition cycles by multiple dipping have been studied and surface morphology, changes in the optical absorption characteristics, thickness, uniformity, roughness and electrical characteristics are reported. The multilayered assemblies, attached to the surface by strong ionic bonds, were highly stable and could not be removed by moderate scratching. The current–voltage characteristics in the forward and reverse bias conditions demonstrated rectifying behaviors in the onset of conduction voltage which makes these films attractive for future electronic devices.