Sigma hd field emission gun scanning electron microscope

One-centimetre sections of tubing were cut in half lengthwise and incubated overnight in 2.5% glutaraldehyde solution (Contain; Fisher Scientific), followed by immersion in successive concentrations of ethanol for 10 min each (10%, 25%, 50%, 70%, 90%, 100%). Prior to scanning electron microscopy scanning, samples were coated with 20 nm AuPd coating with sputter coater (SC500; Biorad, Hercules, CA, USA). Secondary electron images were acquired with a beam energy of 5 kV using an in-lens detector on a Sigma HD field emission gun scanning electron microscope (Carl Zeiss Ltd., Cambridge, UK) at 1000x magnification and 5e7-mm working distance with the help of the Earth and Ocean Sciences Department, Cardiff University, UK. The images were false-coloured using GNU Image manipulation program (GIMP 2.8) software. The images were not otherwise altered.

Three randomly selected samples from keyboards, folders, hospital commode and chair seating were analysed with SEM to visualise the presence of dry biofilms. Samples were prepared by overnight incubation in 2.5% glutaraldehyde solution (Contain™, Fisher Scientific, Loughborough, UK) followed by immersion in successive concentrations of ethanol for 10 minutes each (10%, 25%, 50%, 70%, 90%, 100%). Prior to SEM scanning, samples were coated with 20 nm AuPd coating with sputter coater (SC500, Biorad, UK).
Secondary electron images were acquired with a beam energy of 5kV using an in-lens detector on a Sigma HD Field Emission Gun Scanning Electron Microscope (Carl Zeiss Ltd., Cambridge, UK) at 10,000x magnification and 5-7 mm working distance with the help of Earth and Ocean Sciences Department, Cardiff University, UK.