A flexible, quantum dot-labeled cantilever post array for studying cellular microforces

Geometric Considerations of Micro‐ to Nanoscale Elastomeric Post Arrays to Study Cellular Traction Forces

“…By incorporating a contrast enhancement agent into SU-8 photolithography, arrays of SU-8 posts with a diameter of 2 lm and center-to-center spacing of 5-6 lm have been produced. [16] Achieving even higher density arrays with SU-8-based micromolding methods is difficult due to diffraction effects and other process factors in patterning tall SU-8 structures. [17] To overcome this limitation, conventional photolithography and deep reactive ion etching have been used to fabricate arrays of holes in silicon, from which posts with diameters as small as 1 lm and center-to-center distances of 3 lm have been cast.…”

“…Based on Equation 1, these dimensions capture a range of post stiffnesses from 4.6 to 74 nN lm -1 , which encompasses post stiffness values previously reported in literature. [15,16,18,19] We used i-line projection photolithography to pattern these post array geometries on the same silicon wafer, followed by deep reactive ion etching (DRIE) of exposed silicon. To eliminate the problem of clogging silicon masters when casting with polydimethylsiloxane (PDMS), we etched silicon posts rather than holes, and generated positive replicas of these nanopost arrays by double casting with PDMS ( Fig.…”

Fundamentals of Microfluidics Devices

“…It is an important technique for the fabrication of micro-and nanostructures. 109 Lithography techniques can be divided based on the kind of energy beam used for illumination: electron beam (e-beam) lithography, 110-113 X-ray lithography for the LIGA technique (German acronym of "Lithographie Galvanoformung Abformung"), 114,115 ion beam lithography, 116,117 normal I-line photolithography, 118 and deep UV lithography 119 are some of the major subcategories. Of these subcategories, photolithography and X-ray lithography are still predominantly used for fabrication of microfluidic devices.…”

“…Normally, to facilitate mold release, the surface of the PDMS master mold is treated with fluorinated or chlorinated silanes such as (tridecafluoro-1,1,2,2-tetrahydrooctyl)-1-trichlorosilane. 118,134 In the case of micromolding in capillaries, the PDMS master mold is placed on another flat surface such as glass and then pressed down. This process causes the walls of the relief structure to form capillary channels on the flat surface.…”

Cryogenic Etching of Silicon: An Alternative Method for Fabrication of Vertical Microcantilever Master Molds

“…The motivation for pursuing the cryogenic etching approach is to overcome the limitations of the original soft lithography technique which uses SU-8, a thick polymer photoresist for making the master molds for the microcantilever arrays. Though this method has proven to be simple, we have experienced some limitations in fabricating PDMS microcantilever arrays that we and other groups have previously reported [17], [19]. …”