Low Cost and Lithography-free Stamp fabrication for Microcontact Printing

Abstract

Microcontact printing (µCP) is a commonly used technique for patterning proteins of interest on substrates. The cells take the shape of these printed patterns. This technique is used to explore the effect of cellular morphology on their various functions such as survival, differentiation, migration, etc. An essential step for µCP is to fabricate a stamp from a silicon mould, prepared using lithography. Lithography is cost intensive and needs a high level of expertise to handle the instrumentation. Also, one stamp can be used to print patterns of one size and shape. Here, to overcome these limitations, we devised a low-cost fabrication technique using readily available objects such as injection needles and polystyrene beads. We patterned the C2C12, myoblasts cells on the shapes printed using lithography-free fabricated stamps. We further exploited the surface curvature of the stamp to vary the size of the print either by changing the applied load and/or the substrate stiffness. We showed that the print dimension could be predicted well by using JKR theory of contact mechanics. Moreover, some innovative improvisations enabled us to print complex shapes, which would be otherwise difficult with conventional lithography technique. We envisage that this low cost and easy to fabricate method will allow many research laboratories with limited resources to perform exciting research which is at present out of their reach.

Fabrication of Tapered 3D Microstructure Arrays Using Dual-Exposure Lithography (DEL)

“…Another field that broadly employs MSAs is the surface pattering of small molecules and proteins, which are found in a wide range of applications such as biosensors [ 73 ], disease diagnostic tools like detection of COVID-19 [ 74 , 75 ], cell culturing [ 40 , 76 , 77 , 78 ], and other analytical experiments [ 79 ]. Explicitly, PDMS MSAs are widely used because of their low cost of ownership and inherent hydrophobicity, which provides a favored surface for protein adsorption [ 78 ].…”

Effect of design geometry, exposure energy, cytophilic molecules, cell type and load in fabrication of single-cell arrays using micro-contact printing

“…PDMS is known to shrink when cured 36 , 37 , and this shrinking may contribute to the differences observed. Recently Khadpekar et al showed that the width of the imprinted spots also depends on the weight applied onto the stamp during 38 . Adding a weight onto the stamps during stamping is expected to improve the transfer of the chemical from the PDMS pillar to the surface.…”

Microfabrication With Very Low-Average Power of Green Light to Produce PDMS Microchips

“…Requirements for microfluidic devices are well established, scalability [9], reproducibility [10], and user-friendly characteristics to quickly move from lab-based prototyping to commercial manufacturing [11] are commonly specified. Typical microchips production may entail, for example, photolithography [12], microcontact printing [13][14][15], replica molding [16], or, as we show here, laser ablation.…”