Monthly Archives: January 2016


Hot off the press

Micro-contact printing, μCP, is a well-established soft-lithography technique for printing biomolecules. μCP uses stamps made of Poly(dimethylsiloxane), PDMS, made by replicating a microstructured silicon master fabricated by semiconductor manufacturing processes. One of the problems of the μCP is the difficult control of the printing process, which, because of the high compressibility of PDMS, is very sensitive to minute changes in the applied pressure. This over-sensitive response leads to frequent and/or uncontrollable collapse of the stamps with high aspect ratios, thus decreasing the printing accuracy and reproducibility. Here we present a straightforward methodology of designing and fabricating PDMS structures with an architecture which uses the collapse of the stamp to reduce, rather than enlarge the variability of the printing. The PDMS stamp, organized as an array of pyramidal micro-posts, whose ceiling collapses when pressed on a flat surface, replicates the structure of the silicon master fabricated by anisotropic wet etching. Upon application of pressure, depending on the size of, and the pitch between, the PDMS pyramids, an air gap is formed surrounding either the entire array, or individual posts. The printing technology, which also exhibits a remarkably low background noise for fluorescence detection, may find applications when the clear demarcation of the shapes of protein patterns and the distance between them are critical, such as microarrays and studies of cell patterning.

This article is open access - enjoy it! :)


BµF Team



Photonics West – 13-18 Feb 2016


Meet us at SPIE Conference on February 13-18 in beautiful San Francisco. We will gladly answer any of your questions during the presentations if you happen to be there.

Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues IX

Monday - Wednesday 15 - 17 February 2016

Movement of bacteria in urban microfluidics: a method for biosimulation of complex traffic

Session 3:
Regenerative, Pilot and Industrial Cell and Tissue Growth
Monday 15 February 2016
1:50 PM - 4:40 PM

Paper 9711-19
Time: 4:20 PM - 4:40 PM
Author(s): Viola Tokarova, McGill Univ. (Canada); Ben Libberton, Univ. of Liverpool (United Kingdom); Ondrej Kaspar, McGill Univ. (Canada); Sylvain Martel, Ecole Polytechnique de Montréal (Canada); Dan V. Nicolau, McGill Univ. (Canada)

Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications XIII

Monday - Wednesday 15 - 17 February 2016

Water nanodroplets on micro/nano-arrays: visualization by AFM and simulation

Session 4:
Nanoscale Imaging and Spectroscopy II
Wednesday 17 February 2016

Paper 9721-15
Time: 1:20 PM - 1:40 PM
Author(s): Ondrej Kaspar, McGill Univ. (Canada); Hailong Zhang, Monash Univ. (Australia); Viola Tokarova, McGill Univ. (Canada); Reinhard I. Boysen, Milton T. W. Hearn, Monash Univ. (Australia); Dan V. Nicolau, McGill Univ. (Canada)