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ROCK IMAGER User's Guide | Chapter 9: Using RI 2, FRAP Benchtop & SONICC Benchtop
If both the SHG and UV-TPEF channels show similar contrast then you can be certain that your sample
is a protein crystal (unless you have fluorescent small molecules present). Note that all protein
material, whether crystalline or not, will show up on the UV-TPEF channel, so it is important to compare
to the SHG channel to determine if it is crystalline.
The use of the UV-TPEF channel provides a clear assessment of each drop which can be seen in
the figure on the next page. In both rows (a) and (b) contrast is observed in both the UV-TPEF and
SHG channel indicating protein crystals. The well imaged in row (c) results in fluorescence but no
SHG, indicating precipitated/aggregated protein. Salt crystals can also produce SHG as shown in
row (d) but result in no fluorescence making it easy to distinguish between salt and protein crystals.
SONICC Results