(a-b) Shaker-incubators adapted for the growth of cyanobacteria Anabaena flosaquae providing controlled illumination, temperature, aeration and CO2. (c-d) Confluent green and pink cultures of Anabaena flosaquae and Halobacteria salinarum respectively, just before harvesting. (e-f) Effective separation of buoyant cells from spent media in separatory funnel for isolation and harvesting of Ana and Halo cells producing GVs. Purified Halo (g) and Ana (h) and Mega (i) GVs as a dense milky-white layer post centrifugally assisted floatation. (j) Resuspended milky-white solutions of purified Ana (left), Halo (middle) and Mega (right) GVs in PBS at OD500,ps ~6 prior to use in ultrasound imaging experiments.