Vacuum desk 5 sputter unit

The substrates with cells grown were washed with PBS and fixed in a mixture of 4% paraformaldehyde (PFA, Electron Microscopy Sciences, Hatfield, PA, USA) and 2% glutaraldehyde (Fisher Scientific, Pittsburgh, PA, USA) in PBS at ambient for 4 h. The samples were then rinsed with deionized water and progressively dehydrated using a Tousimis Autosamdri-815 CO₂ Critical Point Dryer (Tousimis Co., Rockville, MD, USA).
The substrates with and without cells grown were sputter-coated with a gold layer of ~10 nm thick by using a Denton Vacuum Desk V sputter unit (Denton Vacuum, LLC, Moorestown, NJ, USA), and imaged in a JEOL JSM-7600F SEM.

The PDMS substrates with cells grown were washed with PBS and fixed in a mixture of 4% paraformaldehyde (PFA; Electron Microscopy Sciences, Hatfield, PA, USA) and 2% glutaraldehyde (Fisher Scientific, Pittsburgh, PA, USA) in PBS at ambient for 4 h. The samples were then rinsed with deionized water and progressively dehydrated using a Tousimis Autosamdri-815 CO₂ Critical Point Dryer (Tousimis Co., Rockville, MD, USA).
The PDMS substrates with and without cells grown were sputter-coated with a gold layer of ∼10 nm thick by using a Denton Vacuum Desk V sputter unit (Denton Vacuum, LLC, Moorestown, NJ, USA), and imaged in a JEOL JSM-7600F SEM.