Ultrasound-triggered amygdalin drug release across U-87 glioblastoma cell lines from gH625-tagged phase convertible nanodroplets

Ultrasound (US), as a non-invasive and non-ionising technology, has been utilized as an efficient technique for transporting drugs and genes across physiological barriers, such as the blood-brain barrier (BBB), in addition to its use in medical imaging. In Contrast-Enhanced Ultrasound Imaging (CEUS), microbubbles act as an effective delivery vehicle, thereby enhancing cellular uptake of the drug. This characteristic is attributed to the cavitation property of the microbubbles. In this study, we synthesised gH625-tagged pre-Polyglycerolsebacate encapsulating a perfluoropentane core (Pre-PGS-PFP) nanodroplets with improved internalisation properties and the ability to deliver a payload by phase converting to phase convertible nanodroplets upon insonation. Amygdalin, as an anticancerous drug, was loaded in the polymeric shell of Pre-PGS-PFP phase convertible nanodroplets using the solvent displacement method and was conjugated to the membrane-crossing peptide (gH625) using NHS-EDC coupling. The nanodroplets were physicochemically characterized using FTIR, SEM, confocal microscopy and zeta analysis. The nanodroplets were found to load 80.10% of Amygdalin. Cytotoxicity and uptake studies in U87 glioblastoma cells demonstrated that ultrasound-triggered amygdalin release significantly enhanced cell death compared to diffusion-based release or treatment with free Amygdalin. Furthermore, the presence of gH625 further improved cellular uptake due to its membrane-penetrating ability. Overall, the synergistic effect of ultrasound activation and gH625 functionalization facilitated efficient internalization and localized drug release, suggesting a promising strategy for targeted delivery and therapeutic enhancement in the treatment of glioblastoma.