you have a cell suspension containing 4*10^5 cells/ml and want to seed these cells on microcarriers at a density of 1*10^4 cells/cm^2. The average diameter of the microcarriers is 157.5um (the diameter range supplied by the vendor is 115-200 um). what is the average suface area of the microcarriers? what number of microcarriers should you use to obtain an average suface area of 100 cm^2? What volume of your cell suspecsion should be added to achieve the density given, using the surface area of 100 cm^2?