Publications by Josias Basil Wacker

Wearable Sensors for Frequency-Multiplexed EIT and Multilead ECG Data Acquisition

Josias Basil Wacker, Michaël Rapin, Fabian Braun

This paper presents a wearable sensor architecture for frequency-multiplexed electrical impedance tomography (EIT) and synchronous multilead electrocardiogram (ECG) data acquisition. The system is based on a novel electronic sensing architecture, called co ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2019

Spherical superstructures of oxide nanoparticles for catalytic reactions in microchemical reactors

Martinus Gijs, Virendra Kumar Parashar, Josias Basil Wacker

We report the fabrication of spherical superstructures composed of SiO2 and TiO2 nanoparticles and their applications in catalyzing organic reactions. Assembling of the nanoparticles into superstructures is done by heating a water-in-oil micro-emulsion, wh ...

Elsevier Science Bv2015

Microfluidic chip for monitoring Ca2+ transport through a confluent layer of intestinal cells

Martinus Gijs, Paolo Silacci, Guy Vergères, Hüseyin Cumhur Tekin, Josias Basil Wacker, Christine Ruffert

The absorption of dietary calcium through the intestinal barrier is essential for maintaining health in general and especially of the bone system. We propose a microfluidic model that studies free calcium (Ca2+) transport through a confluent monolayer of C ...

Royal Soc Chemistry2014

A microfluidic process for on-chip formation of assemblies of oxide nanoparticles

Martinus Gijs, Virendra Kumar Parashar, Josias Basil Wacker, Danut Necula

We report the continuous growth of spherical assemblies of silica and titania nanoparticles, which were pre-activated to produce hydroxyl/ peroxy groups on their surface, by flowing a colloid-in-dioctyl phthalate emulsion into a polydimethylsiloxane microf ...

Royal Soc Chemistry2014

Large spherical assemblies of oxide nanoparticles

Martinus Gijs, Virendra Kumar Parashar, Josias Basil Wacker

2014

Controlled synthesis of fluorescent silica nanoparticles inside microfluidic droplets

Martinus Gijs, Virendra Kumar Parashar, Josias Basil Wacker, Ioannis Lignos

We study the droplet-based synthesis of fluorescent silica nanoparticles (50–350 nm size) in a microfluidic chip. Fluorescein-isothiocyanate (FITC) dye is first chemically linked to aminopropyl triethoxysilane (APTES) in ethanol and this reaction product i ...

Royal Society of Chemistry2012

Grafting submicron titania particles with gold nanoparticles using droplet microfluidics

Martinus Gijs, Virendra Kumar Parashar, Josias Basil Wacker

A microfluidic method to synthesize gold–titania nanocomposites is presented. Porous TiO2 particles are first loaded with a reducing agent and then suspended in water and mixed with chloroauric acid (HAuCl4) in a droplet-by-droplet manner on a microfluidic ...

2012

From Particles to Pillars : Droplet Microfluidics Applied to the Synthesis and Assembly of Functional Metal-Oxide Nanoparticles

Josias Basil Wacker

Metal oxide nanoparticles and their applications (e.g. in nano-electronics, nano-optics or drug delivery) have seen a growing interest in the past decades. Traditional procedures to synthesize, functionalize and integrate nanoparticles in devices mostly ha ...

EPFL2012

Anisotropic Magnetic Porous Assemblies of Oxide Nanoparticles Interconnected Via Silica Bridges for Catalytic Application

Martinus Gijs, Virendra Kumar Parashar, Josias Basil Wacker

We report the microfluidic chip-based assembly of colloidal silanol-functionalized silica nanoparticles using monodisperse water-in-oil droplets as templates. The nanoparticles are linked via silica bridges, thereby forming superstructures that range from ...

American Chemical Society2011

Exotic droplets formed in microfluidic chips with uniform wettability

Martinus Gijs, Virendra Kumar Parashar, Cédric Razaname, Josias Basil Wacker, Guillaume Louis

Microdroplets are widely used in industrial processes. In the absence of external forces, droplets generally assume a spherical shape. Here, we present two methods to form non-spherical droplets in microfluidic glass chips. A uniformly hydrophobized chip h ...

Elsevier2011

From particles to pillars: on-chip synthesis of silica nanoparticle assemblies with controlled shape and size

Martinus Gijs, Virendra Kumar Parashar, Josias Basil Wacker

We describe the assembly of silica nanoparticles into superstructures with controlled shape and size. The individual nanoparticles are chemically linked to each other via silica bridges, thus providing high mechanical stability to the assembly. Key to cont ...

IEEE2011

Controlled Microsynthesis of Silica Particles in a Microfluidic Setup

Martinus Gijs, Virendra Kumar Parashar, Josias Basil Wacker

We report on a novel microsynthesis method for easy controlling the size of silica micro- and nanoparticles. Colloids are synthesized in a microfluidic chamber by layer-wise adsorption of silica to precipitated nuclei. We prepare samples of spherical parti ...

Elsevier Science, Reg Sales Off, Customer Support Dept, 655 Ave Of The Americas, New York, Ny 10010 Usa2009

Influence of Oil Type and Viscosity on Droplet Size in a Flow Focusing Microfluidic Device

Martinus Gijs, Virendra Kumar Parashar, Josias Basil Wacker

We form water-in-oil droplets in a microfluidic channel-nozzle geometry for studying the influence of viscosity of oil and of different oil classes on the droplet size. We find that the chemical structure of oil dominates over its viscosity. Our studies ar ...

Elsevier Science, Reg Sales Off, Customer Support Dept, 655 Ave Of The Americas, New York, Ny 10010 Usa2009