In a general aspect, an apparatus for washing biological material is provided which includes an outer sleeve, and an inner sleeve disposed within the outer sleeve. The outer sleeve has an open end for receiving the biological material, and an opposed closed end. The inner sleeve is detachably and slidably positioned within the outer sleeve, and includes a first port for receiving and dispensing washing liquid, a second port defining a liquid flow path between an interior of the inner sleeve and an interior of the outer sleeve, and a filter disposed in the second port. The filter allows passage of washing liquid but not passage of the biological material therethrough. A chamber, formed between the filter and the closed end of the outer sleeve, is configured to permit flow of washing liquid via the filter while retaining the biological material therein.