Disclosed herein are cellular cassettes for the storage, collection, and analysis of biological samples. The cellular cassette can enable easy sample collection and sealing of microwell arrays with semi-permeable membrane for stable storage and future processing of single cells. Also disclosed herein are systems and kits comprising one or more described cassettes. The described cassettes, systems, and kits can be used to create barcoded, single-cell sequencing libraries. Further described herein are methods of using the cassettes, systems, and kits.