Improved anti-stiction coating of SU-8 molds

Moresco, Jacob Lange; Clausen, Chris; Svendsen, Winnie Edith

doi:10.1016/j.snb.2010.01.020

Cited by 15 publications

(8 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A hydrophobic coating of FDTS (perfluorodecyltrichlorosilane; ABCR, GmBH, Germany) is applied to this SU-8/Si master via molecular vapour deposition. This coating is notably essential for the durability of the SU-8 master and to facilitate the release of the PDMS stamps [23] . PDMS stamps are produced using standard soft lithography, as extensively described in the literature [24] .…”

Section: Methodsmentioning

confidence: 99%

Microstamped Petri Dishes for Scanning Electrochemical Microscopy Analysis of Arrays of Microtissues

et al. 2014

View full text Add to dashboard Cite

While scanning electrochemical microscopy (SECM) is a powerful technique for non-invasive analysis of cells, SECM-based assays remain scarce and have been mainly limited so far to single cells, which is mostly due to the absence of suitable platform for experimentation on 3D cellular aggregates or microtissues. Here, we report stamping of a Petri dish with a microwell array for large-scale production of microtissues followed by their in situ analysis using SECM. The platform is realized by hot embossing arrays of microwells (200 μm depth; 400 μm diameter) in commercially available Petri dishes, using a PDMS stamp. Microtissues form spontaneously in the microwells, which is demonstrated here using various cell lines (e.g., HeLa, C2C12, HepG2 and MCF-7). Next, the respiratory activity of live HeLa microtissues is assessed by monitoring the oxygen reduction current in constant height mode and at various distances above the platform surface. Typically, at a 40 μm distance from the microtissue, a 30% decrease in the oxygen reduction current is measured, while above 250 μm, no influence of the presence of the microtissues is detected. After exposure to a model drug (50% ethanol), no such changes in oxygen concentration are found at any height in solution, which reflects that microtissues are not viable anymore. This is furthermore confirmed using conventional live/dead fluorescent stains. This live/dead assay demonstrates the capability of the proposed approach combining SECM and microtissue arrays formed in a stamped Petri dish for conducting cellular assays in a non-invasive way on 3D cellular models.

show abstract

Section: Methodsmentioning

confidence: 99%

Microstamped Petri Dishes for Scanning Electrochemical Microscopy Analysis of Arrays of Microtissues

et al. 2014

View full text Add to dashboard Cite

show abstract

“…The fabrication process is similar for the two chip types: Gold electrodes were defined on 4-inch Pyrex wafers by photolithography, e-beam vapor deposition and lift-off, using titanium as an adhesive layer. On top of the electrodes the channels were formed in SU-8 2005 (MicroChem, Berlin, Germany) by negative photolithography as described by Demierre et al [ 27 , 28 ]. The channels were sealed using a second Pyrex wafer (lid wafer) with openings for electrode access and fluidic inlet and outlet defined using powder blasting.…”

Section: Methodsmentioning

confidence: 99%

Bacteria Detection and Differentiation Using Impedance Flow Cytometry

Clausen¹,

Dimaki

Bertelsen

et al. 2018

Sensors

Self Cite

View full text Add to dashboard Cite

Monitoring of bacteria concentrations is of great importance in drinking water management. Continuous real-time monitoring enables better microbiological control of the water and helps prevent contaminated water from reaching the households. We have developed a microfluidic sensor with the potential to accurately assess bacteria levels in drinking water in real-time. Multi frequency electrical impedance spectroscopy is used to monitor a liquid sample, while it is continuously passed through the sensor. We investigate three aspects of this sensor: First we show that the sensor is able to differentiate Escherichia coli (Gram-negative) bacteria from solid particles (polystyrene beads) based on an electrical response in the high frequency phase and individually enumerate the two samples. Next, we demonstrate the sensor’s ability to measure the bacteria concentration by comparing the results to those obtained by the traditional CFU counting method. Last, we show the sensor’s potential to distinguish between different bacteria types by detecting different signatures for S. aureus and E. coli mixed in the same sample. Our investigations show that the sensor has the potential to be extremely effective at detecting sudden bacterial contaminations found in drinking water, and eventually also identify them.

show abstract

“…One hundred-nanometer gold electrodes, with a 20-nm titanium layer for adhesion, were defined on 4-inch Pyrex wafers by a negative photolithography process (resist AZ5214e). On top of the electrodes, the channels were formed in SU-8 2075 (MicroChem, Germany) by photolithography [ 23 , 24 ]. For the experiments, the chips were reversibly sealed with a polydimethylsiloxane (PDMS) lid (Dow Corning, Germany), which was clamped to the chip by a customized holder.…”

Section: Methodsmentioning

confidence: 99%

Study of Paclitaxel-Treated HeLa Cells by Differential Electrical Impedance Flow Cytometry

et al. 2014

Self Cite

View full text Add to dashboard Cite

This work describes the electrical investigation of paclitaxel-treated HeLa cells using a custom-made microfluidic biosensor for whole cell analysis in continuous flow. We apply the method of differential electrical impedance spectroscopy to treated HeLa cells in order to elucidate the changes in electrical properties compared with non-treated cells. We found that our microfluidic system was able to distinguish between treated and non-treated cells. Furthermore, we utilize a model for electrical impedance spectroscopy in order to perform a theoretical study to clarify our results. This study focuses on investigating the changes in the electrical properties of the cell membrane caused by the effect of paclitaxel. We observe good agreement between the model and the obtained results. This establishes the proof-of-concept for the application in cell drug therapy.

show abstract

Improved anti-stiction coating of SU-8 molds

Cited by 15 publications

References 5 publications

Microstamped Petri Dishes for Scanning Electrochemical Microscopy Analysis of Arrays of Microtissues

Microstamped Petri Dishes for Scanning Electrochemical Microscopy Analysis of Arrays of Microtissues

Bacteria Detection and Differentiation Using Impedance Flow Cytometry

Study of Paclitaxel-Treated HeLa Cells by Differential Electrical Impedance Flow Cytometry

Contact Info

Product

Resources

About