Hexamethyldisilazane

Cell morphology was studied by scanning electron microscopy (SEM). Briefly, the organisms were grown in CYE broth for 3 days, centrifuged at 10,400 × g for 15 min, and washed twice with TM buffer. The pellet was fixed with 2.5% glutaraldehyde in 0.1 M sodium cacodylate (pH 7.2) and then with 1% osmium tetroxide in 0.1 M sodium cacodylate (pH 7.2). The sample was then dehydrated in an aqueous alcohol series (30%, 50%, 70%, 95%, and 100%) and critical-point dried with hexamethyldisilazane (TAAB Laboratories Equipment Ltd., Aldermaston, UK). The sample was coated in an agar high-resolution sputter coater using a platinum/palladium target to give a coating layer of 6.0 nm and imaged using a Hitachi S-4700 FESEM microscope.

Scanning electron microscopy (SEM) was conducted on a Cambridge Stereoscan S90B (Cambridge Instruments, UK). Samples from the Calcein-AM-based experiment were fixed immediately after fluorescence measurements in 3% glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.3) (Agar Scientific, Stansted, Essex, UK) at 4°C overnight. Samples were later dehydrated in a graded series of alcohols (50%, 70%, 90%, and twice with 100%) and critically dried in hexamethyldisilazane (TAAB Laboratories Ltd., Reading, Berkshire, UK) for 5 min at room temperature. Samples were imaged with back-scattered SEM, which differentiates between an inorganic bright background and opaque/dark organic cells. A manual count was performed to verify the relative difference in the number of adherent MSCs on each surface. These samples were sputter coated with gold/palladium using a Polaron E5000 Sputter Coater (Quorum Technologies Ltd., Newhaven, East Sussex, UK) and visualised with SEM.