T. Yasukawa et al., Dual imaging of topography and photosynthetic activity of a single protoplast by scanning electrochemical microscopy, ANALYT CHEM, 71(20), 1999, pp. 4637-4641
Two types (A and B; see Figure 1 in the text) of dual-Pt microdisk electrod
es (disk radius, 0.5-4.0 mu m; whole tip radius, 5.0-15 mu m) were fabricat
ed to simultaneously detect two electroactive species near a single algal p
rotoplast (radius, 25 mu m). At the tip of type A, the two disks were on th
e same plane. Two disk planes of electrode type B formed an angle of simila
r to 135 degrees at the tip. Cyclic voltammetric investigation indicated th
at, compared with type At one disk in type B only slightly collected the sp
ecies electrogenerated at the other disk. These dual-microdisk electrodes w
ere applied to electrochemical measurements of a single protoplast in artif
icial seawater. The topographic profiles Of the single protoplast were obta
ined from the variation of oxidation current for 1.0 mM Fe(CN)(6)(4-) at on
e disk. The photosynthetic oxygen generation from the protoplast was also m
onitored by detecting the reduction current for oxygen at another disk. The
electrode of type B was used as a probe for scanning electrochemical micro
scopy (SECM) to obtain dual-SECM images of topography and activity of a sin
gle protoplast.