The microbubble suspension prepared using sonication method generally has a broad size distribution (0.1 - 20 µm or more). Therefore, microbubbles sample are treated to size isolation using centrifugal separation technique to produce a very narrow distribution of 3 - 5 µm microbubbles. At present, we are investigating the effect of various material properties such as effect of various additives, microbubbles aqueous storage medium, aqueous solubility of gases used on size, size distribution, Ostwald ripening, and on the stability of microbubbles.

Microbubbles can be produced through a variety of techniques, including sonication, amalgamation, and saline shaking. Although these methods may yield extremely concentrated microbubble suspensions, they provide little control over the size and polydispersity of the microbubble suspension. Capillary-embedded T-junction microfluidic systems, which offer superior control over microbubble size, are one of the simplest and most effective methods for creating monodisperse microbubbles. However, due to the lower production rates (200 bubbles/s) and huge microbubble diameters (~300 microns), such devices are not suitable for biological applications. To address the limitations of current technologies, we are working on to combine capillary-embedded T-junction devices with ultrasound to improve the formation of narrow-sized microbubbles in aqueous suspensions.

Microbubble shells can be functionalized with various drug moieties and fluorescent proteins for biological activity. We have functionalized microbubbles using porphyrin as a model drug molecule. Upon functionalizing the microbubble with porphyrin, the microbubbles exhibited bright red fluorescence. The fluorescence images were captured using a confocal microscope. The fluorescence images show that the microbubble shell was completely functionalized with porphyrin. These functionalized microbubbles can be used for various therapeutic applications

We conducted B-mode imaging of lipid-shelled microbubbles generated utilising T-junction paired with sonication in collaboration with the MUSE lab at IITGN. Using B-mode imaging, we discovered that increasing the microbubble concentration from 10⁵ to 10⁷ MBs/mL boosts the contrast ultrasound images. When the microbubble concentration was increased from 10⁵ to 10⁷ MBs/ml, the CTR and CNR values increased from 8.1±1.4 to 29.5±1.2 and 8.8±2.3 to 33.2±1. This demonstrates that microbubbles created using microfluidics and sonication can increase the contrast of an ultrasound image.