The invention is an apparatus comprising a magnet adapted to create a diamagnetic force field at all points in space at which a magnetic field-field gradient product of the magnet has a value greater than or equal to a threshold value. At or above the threshold value, the diamagnetic force field induces a diamagnetic body force within a biological specimen supported within a bioreactor chamber that is disposed within the diamagnetic force field. The apparatus may alter the magnitude of the induced diamagnetic body force and may alter the direction of the induced diamagnetic body with respect to a spatial coordinate system or with respect to the direction of a secondary body force acting upon or within the biological specimen, thereby altering the vector sum of the induced diamagnetic body force and the secondary body force acting on the biological specimen.