title: Protein patterning by microcontact printing using pyramidal PDMS stamps.
abstract: 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.
authors.affiliation: Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Science, Swinburne University of Technology, PO Box 218, VIC, 3122, Australia.
authors.forename: Luisa
authors.initials: L
authors.lastname: Filipponi
authors.affiliation: Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Science, Swinburne University of Technology, PO Box 218, VIC, 3122, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Livingston
authors.affiliation: Faculty of Engineering, Department of Bioengineering, McGill University, Macdonald Engineering Building, Room 378, 817 Sherbrooke Street West, Montreal, QC, H3A 0C3, Canada.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Kašpar
authors.affiliation: Faculty of Engineering, Department of Bioengineering, McGill University, Macdonald Engineering Building, Room 378, 817 Sherbrooke Street West, Montreal, QC, H3A 0C3, Canada.
authors.forename: Viola
authors.initials: V
authors.lastname: Tokárová
authors.affiliation: Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Science, Swinburne University of Technology, PO Box 218, VIC, 3122, Australia. dan.nicolau@mcgill.ca.|Faculty of Engineering, Department of Bioengineering, McGill University, Macdonald Engineering Building, Room 378, 817 Sherbrooke Street West, Montreal, QC, H3A 0C3, Canada. dan.nicolau@mcgill.ca.
authors.forename: Dan V
authors.initials: DV
authors.lastname: Nicolau
mesh_terms: D000818:Animals; D004129:Dimethylpolysiloxanes; D007074:Immunoglobulin G / Q000737:chemistry*; D040081:Protein Array Analysis / Q000295:instrumentation* / Q000379:methods*; D011817:Rabbits
chemical_list: D004129:Dimethylpolysiloxanes; D007074:Immunoglobulin G; C013830:baysilon
keywords: Microcontact printing; Poly(dimethylsiloxane) microstructures; Protein microarrays; Protein patterning; Soft-lithography