Observation of on-chip electrophoresis microcapillary using confocal laser scanning microscopy

Confocal laser scanning microscopy (CLSM) is used to observe a fluorescent sample in an on-chip electrophoresis microcapillary fabricated on a photosensitive glass. CLSM is a powerful tool for observing the sample inside a channel since it can capture fluorescence images sliced in the plane perpendicular to the optical axis and can vary the laser focal plane depth. In the photosensitive glass, since the UV-irradiated part of the glass has an etching rate 20 times higher than the other parts, we can obtain a channel structure with a high aspect ratio, which is valuable to the high-sensitivity detection of the signal. Inside the channel, it is found that the sample behavior at the middle depth of the channel differs from that at the top of the channel during the sample loading and electrophoresis. The CLSM observation can reveal the phenomena occurring inside the channel in detail.