Monitoring activity of living cells entrapped in a membrane-sealed microcapillary with scanning electrochemical microscopy

The respiration- or photosynthesis-induced change of oxygen concentration w as monitored with scanning electrochemical microscopy (SECM). Cell suspensi on was put into a glass capillary tube and then one edge was sealed with an oxygen permeable membrane. The total volume of the cell suspension in the capillary was as small as 10 muL. The edge of the sealed capillary was imag ed with SECM based on oxygen reduction current. The images indicated the re spiration activity as low as 2.0 x 10(3) HeLa-S3 cells. This method was als o applied far imaging the respiration and photosynthesis activities of a si ngle alga (Bryopsis plumosa) protoplast.