Alexa Fluor Plus 800 shows more bands at lower dilutions, providing greater sensitivity and range of detection – secondary antibody conjugates of Alexa Fluor Plus 800 goat anti-rabbit (top) vs. competitor (bottom). Western blot analysis of heat shock protein 90 (Hsp90) and histone deacetylase 1 (HDAC1) was performed by loading 3-fold serial dilutions of A431 whole cell lysate (starting at 15 µg) and 2 µL of the Thermo Scientific PageRuler Prestained NIR Protein Ladder (Cat. No. 26635) per well onto a 4-20% Tris-HCl polyacrylamide gel. Proteins were transferred to nitrocellulose membranes (Cat. No. 88018) and blocked with fluorescence blocker for 30 min. Membranes were probed with a Hsp90 polyclonal antibody (Cat. No. PA3-013) at a dilution of 1:5,000 and an HDAC1 polyclonal antibody (Cat. No. PA1-1110) at a dilution of 1:5,000 overnight at 4°C on a rocking platform, washed with TBST, and probed with either Alexa Fluor Plus 800 goat anti-rabbit IgG (Cat. No. A32735) at a dilution of 1:40,000 or another supplier’s goat anti-rabbit 800 IgG conjugate at dilution of 1:15,000 for 45 minutes. Blots were imaged on an infrared fluorescence imaging system.