Concept for a solid-state multi-parameter sensor system for cell-culture monitoring

A Cu-Ni thin film combinatorial library deposited using a co-evaporation technique was screened for electrocatalytic oxidation of glucose in NaOH electrolyte using a flow-type scanning droplet cell microscope. The crystallographic characteristics and surface microstructure were mapped along the compositional spread using scanning XRD and SEM. The obtained compositional spread of approximately 1-14 at.% Ni showed suitability for being used in glucose detection as evidenced by cyclic voltammetry studies. Increasing the Ni amount resulted in increased glucose electrocatalytic oxidation. The linearity observed between the current density and inverse scan rate for various rates of potential increase revealed a diffusion limited process. Amperometric measurements performed at various applied potentials indicated an increase in the current density plateaus responsible for glucose detection of more than 5 mA cm À2 .

Section: Introductionmentioning

confidence: 99%

Electrocatalytic oxidation of glucose by screening combinatorial copper–nickel alloys

Pötzelberger

Mardare

Hassel

2015

“…Ta 2 O 5 is well known for its outstanding properties for field‐effect pH sensing, having a nearly Nernstian pH sensitivity as well as a high corrosion resistance in a wide pH range 13. Additionally, the suitability of EIS structures for sterilization‐in‐place (SIP) and cleaning‐in‐place (CIP) has previously been demonstrated 11, 14.…”

Section: Sensor Working Principlesmentioning

confidence: 99%

“…The sensor chip comprises an electrolyte‐insulator‐semiconductor (EIS) field‐effect structure for monitoring the pH value, a platinum thermistor for temperature measurements, and an impedance sensor based on interdigitated electrodes (IDE) for measuring the electrolyte conductivity. The chip represents one part of a sensor system that is developed as a tool for bioprocess monitoring 11.…”

Section: Introductionmentioning

confidence: 99%

A silicon‐based multi‐sensor chip for monitoring of fermentation processes

Bäcker

Pouyeshman

Schnitzler

et al. 2011

Self Cite

This paper describes the design and characterization of a silicon-based sensor chip for monitoring of fermentation processes. The sensor chip consists of three sensors using different transducer principles. A capacitive electrolyteinsulator-semiconductor (EIS) field-effect structure with Ta 2 O 5 as gate material was utilized as pH sensor. An electrolyte conductivity sensor was realized by measuring the impedance between two interdigitated electrodes (IDE). A platinum thermistor was included for temperature measurements. The EIS sensor was integrated into a bioreactor and successfully used for an inline pH measurement. The layout of the IDE has been optimized with respect to a high cell constant and a wide detectable conductivity range. The integrated platinum thermistor allowed for temperature compensation of the electrolyte conductivity measurement.

“…A combination of two or more different kinds of responsive hydrogels in a microfluidic system could provide more functionalities for tuning the flow by the different external stimuli. Moreover, an integration of different kinds of responsive hydrogels, stimuli elements ( e.g ., integrated heater 28 or H + ‐ion generator for a local pH change 29–33) and control sensors ( e.g ., temperature or conductivity sensor, Si‐based pH sensor 34, 35) on the same chip and their combination with logic principles might create a new generation of LOCs, where each hydrogel component could be addressably perform the sensing, actuating or regulating functions in accordance to a logic signal that is ‘programmed’ in the system.…”

Section: Introductionmentioning

confidence: 99%

Microfluidic chip with integrated microvalves based on temperature‐ and pH‐responsive hydrogel thin films

Bäcker

Raue

Schusser

et al. 2012

Self Cite

241-6009-53235 y Both the authors contributed equally to this work.Two types of microvalves based on temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm) and pH-responsive poly(sodium acrylate) (PSA) hydrogel films have been developed and tested. The PNIPAAm and PSA hydrogel films were prepared by means of in situ photopolymerization directly inside the fluidic channel of a microfluidic chip fabricated by combining Si and SU-8 technologies. The swelling/shrinking properties and height changes of the PNIPAAm and PSA films inside the fluidic channel were studied at temperatures of deionized water from 14 to 36 8C and different pH values (pH 3-12) of Titrisol buffer, respectively. Additionally, in separate experiments, the lower critical solution temperature (LCST) of the PNIPAAm hydrogel was investigated by means of a differential scanning calorimetry (DSC) and a surface plasmon resonance (SPR) method. Mass-flow measurements have shown the feasibility of the prepared hydrogel films to work as an on-chip integrated temperature-or pH-responsive microvalve capable to switch the flow channel on/off.