Construction of a liposome dialyzer for the preparation of high-value, small-volume liposome formulations
Katarzyna Adamala, Aaron E Engelhart (Shared First Author), Neha P Kamat, Lin Jin, and Jack W Szostak
Nature Protocols, 2015, 10(6), pp 927-938.
The liposome dialyzer is a small-volume equilibrium dialysis device, built from commercially available materials, that is designed for the rapid exchange of small volumes of an extraliposomal reagent pool against a liposome preparation. The dialyzer is prepared by modification of commercially available dialysis cartridges (Slide-A-Lyzer cassettes), and it consists of a reactor with two 300-μl chambers and a 1.56-cm2 dialysis surface area. The dialyzer is prepared in three stages: (i) disassembling the dialysis cartridges to obtain the required parts, (ii) assembling the dialyzer and (iii) sealing the dialyzer with epoxy. Preparation of the dialyzer takes ~1.5 h, not including overnight epoxy curing. Each round of dialysis takes 1–24 h, depending on the analyte and membrane used. We previously used the dialyzer for small-volume non-enzymatic RNA synthesis reactions inside fatty acid vesicles. In this protocol, we demonstrate other applications, including removal of unencapsulated calcein from vesicles, remote loading and vesicle microscopy.
One model system used as a simplified model of cells employs “vesicles” – cell-like structures formed by lipids that have membranes and internal compartments very much like cells. By taking a solution of the desired components to be encapsulated within a vesicle and using this to rehydrate a lipid, one can make vesicles that contain these components. In many cases, these components are rare and/or expensive, necessitating working with small volumes of reagent. This paper describes a dialysis device with small chambers that allows for the preparation of vesicles and their purification in small volumes.