Improvements are possible in the spectral range of the NIR film and in the focusing unit of the system.
Zhou et al. also tried a low-cost method, in which an optical fiber was used as a focusing unit to etch parallel microgrooves with 2 to 6 μm width and 0.7 to 1.4 μm depth on Si surface[9].
Isoelectric focusing was performed on an Amersham IPGphor Isoelectric focusing unit.
All steps were limited with 75 µA per strip and performed at 20°C (IEF 100 focusing unit, Hoefer Medical Supply).
The noise level is reduced by using a dedicated focusing unit which optimises optical throughput of our microfluidic setup.
Isoelectric focusing was performed on 13 cm immobilized pH gradient strips (pH 4 7NL, Amersham Pharmacia) using an IPGphor (Amersham Pharmacia) isoelectric focusing unit.
One was the optical probe unit of the SS-OCT system mounted on an independent universal stand (Olympus, SZ2-STU2) with a focusing unit (Olympus, BXFM-F), and the other was the electrode penetration probe unit.
The collimated infrared light beam exiting the spectrometer through an external port was focused (focal diameter 1.0 mm) onto a microfluidic flow cell by a homemade focusing unit described in Fig. 9a [ 20].
Isoelectric focussing (IEF) was performed with 142 μg of protein extract diluted in 350 μl rehydration solution using 18-cm linear pH 4 7 IPG gradients (GE Healthcare) and the Ettan IPGphor II isoelectric focusing unit (Amersham Biosciences, Uppsala, Sweden).
