Rapid dissociation of adherent human tumor cells by ultrasound

Cultured human melanoma and gastrointestinal carcinoma cells were detached from substrate and further dissociated by placing the culture vessel into a water-filled ultrasonic cleaner (43 kHz) and sonicating it for 10-50 s. Plating efficiency and long-term growth of three melanoma cell lines were similar after ultrasound or trypsin detachment. Binding of monoclonal antibodies that define normal and tumor-associated antigens on melanoma and colorectal carcinoma cells was not affected by ultrasound in 21 out of 23 cases. The 40 kDa colorectal carcinoma-associated antigen defined by monoclonal antibody CO 17-1A was more highly expressed after ultrasonication than trypsinization. The antigen defined by antibody CO 44.1 on these cells was more sensitive to sonication. This method represents a rapid, effective and gentle alternative to trypsin detachment of cultured cells, especially when repeated cell washing or centrifugation steps are required.