The samples and standards were mixed with WR at a 1:8 in a 96-well plate and place on a shaker to ensure proper mixing. The well plate was then incubated at 37C for 30 minutes before measuring the absorbance at 562 nm. The absorbance of the BSA solution was plotted against the concentrations to achieve a standard curve and a standard curve equation. The protein amount in the cell sample could then be calculated from the equation.