Description
The transmembrane transport of ions by membrane-bound proteins is an essential biological process for maintaining cellular ion balance. Disrupted ion transport by dysfunctional channels, associated with diseases such as cystic fibrosis and epilepsy, could be alleviated by synthetic ion carriers [1]. Before testing the activity of the synthetic ion carriers in real cells, it is generally studied in cell-mimicking lipid vesicles. These cell models can be prepared by different methods, resulting in the formation of vesicles having varied sizes and properties. Large unilamellar vesicles (LUV) with a size range of 100-200 nm and giant unilamellar vesicles (GUV) of size 5-100 µm are potential cell models to study ion transport across the membrane [2].
Here, we present the ion transport studies performed in LUVs prepared by the extrusion method [3] and in GUVs prepared by microfluidics using a double emulsion template [4] and the gel-assisted method [5]. Vesicles of different sizes require ion transport studies to be performed using different methodologies, such as fluorescence spectroscopy in LUVs and fluorescence microscopy in GUVs. We first investigated ion transport in LUVs using fluorescence spectroscopy to compare different macrocyclic transporters [6]. Based on these results, we then examined the activity of the most effective macrocyclic transporter in GUVs prepared by the above-mentioned methods, visualizing ion transport using fluorescence microscopy.
References
[1] Feo, E.; Gale, P. A. Current Opinion in Chemical Biology 2024, 83, 102535.
[2] Valkenier, H.; López Mora, N.; Kros, A.; Davis, A. P. Angew Chem Int Ed 2015, 54, 2137.
[3] Chvojka, M.; Singh, A.; Cataldo, A.; Torres‐Huerta, A.; Konopka, M.; Šindelář, V.; Valkenier, H. Analysis & Sensing 2024, 4, e202300044.
[4] Dewandre, A.; Rivero-Rodriguez, J.; Vitry, Y.; Sobac, B.; Scheid, B. Sci Rep 2020, 10, 21616.
[5] Weinberger, A.; Tsai, F.-C.; Koenderink, G. H.; Schmidt, T. F.; Itri, R.; Meier, W.; Schmatko, T.; Schröder, A.; Marques, C. Biophysical Journal 2013, 105, 154.
[6] Norvaisa, K.; Ummat, H. S.; Halgreen, L.; Piras, G.; Giaprakis, A.; Cataldo, A.; Butler, S. J.; Picci, G.; Caltagirone, C.; Valkenier, H. 2025.