Incubators are disclosed which include an enclosure with an internal chamber configured to support a cell culture plate and provide an environment suitable for maintaining and/or culturing biological cells. The enclosure can include one or more openings configured to allow access to the cell culture plate. The incubators can further include a structure having a plurality of openings configured to be aligned with a corresponding plurality of wells in the cell culture plate, and a sealing element configured to moveably seal the plurality of openings in the structure. The sealing element can comprise a plurality of openings corresponding to at least a subset of the plurality of openings of the structure. Access to the internal chamber can be provided by aligning the plurality of openings in the sealing element with the plurality of openings in the structure. Methods for using the incubators are also provided.