STP-2: SILVER STAINING.  Our excellent silver stain is based on
the ammoniacal silver/formaldehyde method of Oakley et. al. (Anal. Biochem.105: 361, 1980.) This method involves preliminary glutaraldehyde treatment of the slab gel to fix proteins by cross linking. The pre-treatment also adds glutaraldehyde side chains to the proteins, increasing sensitivity since these groups are sites for silver deposition (Dion A, and Pomenti A, Anal. Biochem. 129: 390, 1983). We find this method to be >10 times more sensitive than Coomassie blue staining, depending on the protein, even though less protein is loaded. Generally, 50 ng of purified protein gives a highly visible spot.(see our internal standard). However, some proteins that are detectable with Coomassie don't stain at all with silver. Although very sensitive, this method gives semi-quantitative rather than quantitative results. The linear range for plots of stain density versus ng protein varies from protein to protein with different saturation levels. Day to day variability in stain and background intensity occurs. Even so, silver staining is useful for computerized comparisons because spot values are normalized - expressed as a percentage of all spots combined. Values from duplicate gels are always averaged. Silver staining is not compatible with mass spectroscopy fingerprinting but the patterns match well to a heavily loaded, Coomassie stained duplicate gel. Any spot present on the latter, no matter how faint, is within range for identification mass spectrometry.
Price: STP-2 Standard Format Add $32 per 2D gel; STP-2LF  Large Format add $42 each. Duplicate silvers for computer comparisons are free.

STP-3: SPECIAL SILVER STAINING FOR MASS SPECTROMETRY.  This special silver stain (O’Connell and Stults, Electrophoresis 18: 349-359, 1997) omits the glutaraldehyde step and is compatible with mass spectroscopy fingerprinting. It often negatively stains proteins and so is not appropriate for computerized analysis.  However, the pattern can be matched to our regular stain without difficulty. Note however, that silver deposition interferes with the enzymatic digestion required for mass spectrometry for most mammalian proteins.  If possible use the less sensitive but more reliable Coomassie stain. 
Price: Standard format gels Add $32 per 2D gel; large format gels add $42/gel.

Standard Format 2D Gel Prices: 2D-ES-1: 1 sample, $175; 2D-ES-1A:  2-3 samples, $165 each; 2D-ES-1B:  4-8 samples, $155 each; 2D-ES-1C: 9-20 samples, $144 each; 2D-ES-1D:  21-200 samples, $134 each; 2D-duplicate: $85 each.  More than 200 samples - Inquire.