Improving the robustness of microstencils for single-cell analysis

Given the high variation of cell phenotypes at the population level, a growing number of researchers have turned to single-cell analysis to better understand cell and disease functions. However, handling and manipulation of individual cells remains challenging and expensive. For instance, a method called “microcontact printing” stamps proteins onto the culture surfaces, but the process is complex, slow and inefficient.

As an alternative approach, a new article presents a novel technique to fabricate structurally robust microstencils for single-cell analysis that is cost-effective, versatile and reproducible. The microstencils, constructed out of the polymer polydimethylsiloxane (PDMS), can be reused dozens of times over several months with minimal wear.

While microstencil patterning is not new, the method has been eschewed in favor of microcontact printing due to the fragility of stencils that would often break. The thickness of a microstencil membrane is only 30 to 40 microns. To increase membrane strength, the authors painted a millimeter-thick border of PDMS around the patterned section. Thus, the membrane is reinforced while keeping the stencil area very thin. To validate the effectiveness of this approach, the authors selectively exposed a hydrophobic petri dish — to which cells do not normally adhere — to oxygen plasma through the microstencil. This process created hydrophilic islands corresponding to the stencil holes of any desired shape and dimensions. Cells were seeded to these islands and stayed within their boundaries.

The authors hope that other researchers will adopt this simple and reliable approach to pattern cells for a wide range of future studies.

Source: “Microstencil-based spatial immobilization of individual cells for single cell analysis,” by Khadija Zaidi and Nitin Agrawal, Biomicrofluidics (2018). The article can be accessed at https://doi.org/10.1063/1.5061922 .