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Cell Squeezing as a Robust, Microfluidic Intracellular Delivery Platform
Published on: November 7, 2013
From charge shifting to membrane engagement: next-generation cubosomes for enhanced intracellular drug delivery
Andi Nafisah Tendri Adjeng1, Lena Werner2, Magnus Andre Kiechle2
1Centre for Chemistry and Biomedicine, Department of Pharmaceutical Technology, Institute of Pharmacy, Leopold-Franzens-University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria; Department of Pharmacy, Faculty of Medicine, Universitas Lampung, Bandar Lampung 35141, Indonesia.
Abstract:
This study aimed to engineer cubosomes that shift their surface charge at the epithelial surface via phosphate cleavage by intestinal alkaline phosphatase to enhance membrane engagement. Cubosomes were cationized with cetyltrimethylammonium bromide to yield uncoated cationic (UC), and coated with sodium tripolyphosphate to generate anionic cubosomes (TC). Stability in physiologically relevant media, biocompatibility and cellular uptake of the cubosomes were evaluated. Dephosphorylation by IAP was assessed by zeta potential shifts and phosphate release. Phosphatase-gated cellular uptake was evaluated with and without phosphatase-inhibitor cocktail. Membrane engagement was distinguished from clathrin-dependent endocytosis with and without chlorpromazine at 37 °C and 4 °C. TC were more biocompatible than UC in all concentrations. Zeta potential of TC shifted from + 18.0 mV to - 14.30 ± 0.20 mV after TPP coating. Dephosphorylation was confirmed by TC RMFI, which showed a pronounced difference between incubation ± PIC2 and zeta potential drift to - 0.79 ± 0.10 mV over 24 h. Flow cytometry analysis revealed that TC and UC were taken up by Caco-2 cells predominantly via clathrin-dependent, whereas uptake in HEK293 cells was clathrin-independent. Across all conditions, TC consistently showed higher uptake than UC. According to these results, tripolyphosphate-coated cubosomes are one of the promising carrier systems for intracellular delivery.
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