Premium
LipHosomes: Reporters for Ligand/Anti‐Ligand Assays Based On pH Readout
Author(s) -
Tripepi Martina,
Bennardi Paolo O.,
Ferrauto Giuseppe,
Aime Silvio,
Delli Castelli Daniela
Publication year - 2021
Publication title -
analysis and sensing
Language(s) - English
Resource type - Journals
ISSN - 2629-2742
DOI - 10.1002/anse.202000001
Subject(s) - liposome , biotinylation , ligand (biochemistry) , chemistry , membrane , chromatography , bicarbonate , streptavidin , suspension (topology) , biophysics , semipermeable membrane , biotin , combinatorial chemistry , biochemistry , receptor , organic chemistry , biology , mathematics , homotopy , pure mathematics
A new class of liposomes (LipHosomes) is designed to induce a change of pH upon releasing their content. pH‐readout reports on the number of LipHosomes in the specimen. LipHosomes were prepared by entrapping NaOH or bicarbonate buffer in the intravesicular compartment. The liposomes suspension was purified from unentrapped compounds and brought to pH 7.0. The pH gradient between intra‐ and extra‐liposomal compartments is maintained because the phospholipidic membrane works as a semipermeable membrane thus preventing diffusion of ions across the membrane. The release of the liposomal content triggers a quantifiable variation of the pH of the medium. This feature has been harnessed in analytical assays based on ligand/anti‐ligand molecular recognition by exploiting the biotin‐streptavidin binding scheme. A pH difference of 0.2 units was observed upon the release of the payload from biotinylated LipHosomes bound to streptavidinated plates. The test showed an excellent sensitivity being able to reveal a concentration of bound LipHosomes in the sub‐pM range.