Measurement of forces generated by chemomechanical protein aggregates using polymer BioMEMS

P-protein bodies (forisomes), found in the phloem tissue of legumes, transform the chemical free energy of their reaction with alkaline earth metal ions into mechanical energy. Micromechanical forces generated by the switching of forisomes in aqueous solutions were measured by monitoring the bending of microscale polymer cantilever beams. The forisomes were adsorbed to the tips of four orthogonal beams of a BioMEMS microsystem that was manufactured using the process of sacrificial layer micromolding. The sensor layout allows force measurements in the longitudinal and radial direction of the forisomes. Measurements were performed on eight different forisomes. Longitudinal forces ranged from 84-136 nN with an average of 117 ± 19 nN (± standard deviation) and radial forces were 22-61 nN (44 ± 13 nN).