Currently there are many techniques to measure the bulk modulus. The most standard method is to use a rheometer. However, most rheometers require a "large" amount of volume. "Large" in this case can have different meanings depending of the situation, but for the sake of breivity consider the following situation. A standard rheometer requires about 5 mL of solutions. If one needed to know the viscoelasticity of a precious biological sample, 5 mL may not be easy to come by. Although, for microrheology, only ~ 10 μL is needed, and this is the power of microrheology, that only extremely small sample sizes are needed.