Glass vs Plastic

“Once upon a time” glass ruled the culture world, until the convenience of disposable plastic culture ware began to become more commonplace. There is no hard and fast rule regarding different species and their preference for different culture vessels. The format for most plastic vessels is a variety of sterile (often gamma irradiated or ethylene oxide treated) tissue culture flasks/plates used more widely in the life-sciences. More often than not the surface of tissue culture ware has been chemically treated to promote cell attachment. Due to the massive scale of use in the medical and pharma industry the cost of these “preferred or standard” vessels makes them more cost attractive compared with untreated vessels designed for suspension cells. Some diatoms certainly seem to prefer growing in glass Erlenmeyers rather than Si-replete media in plastic but many are more than happy to grow in the latter. Likewise, most flagellate species grow well in tissue culture flasks but some seem to prefer glass. Paying some attention to the surface treatment may resolve these observations and allow for maintenance of the bulk of strains in cheaper “standard” tissue culture flasks and more recalcitrant strains in the suspension optimised flasks. To allow for sterile gas exchange there is an option with most brands of tissue culture flask to use 0.2 μm membrane filter caps which alleviates the need to loosely cap and tape (e.g. parafilm) normal caps.

The greater use of single use plastics is a concern, especially where recycling companies may be reluctant or prohibited from accepting biologically tainted material (even if autoclaved). Some plastics like polycarbonate can be reused and re-autoclaved (limited times), but then in between transfer cycles they need to be thoroughly cleaned which defeats the major rationale for their adoption in the first place, as a means to eliminate labour intensive washing protocols.