Morphology of microtubules grown in agarose gels: Effect of diffusion and confinement

Morphology of microtubules (MT) grown in crowded environment in the form of high viscosity fluids containing agarose were presented. Agarose influences the diffusion coefficient of molecules in high viscosity solutions and gels. The morphology of MTs were evolved from numerous short, straight MTs to longer MTs to fewer long bundles of MTs that were curved or contorted. Field emission scanning electron microscope (FESEM) showed that the porosity of gel was characterized by large pores separated by a denser network of agarose filaments. The large pores exhibited diameters in the order of hundreds of nanometers, whereas the denser network had small pores with diameters that were not greater than a few tens of nanometers. Experimental investigation demonstrated that the morphology of MTs grown in gels was directly dependent on the tubulin diffusion coefficient.