In Vitro Characterization and Real-Time Label-Free Assessment of the Interaction of Chitosan-Coated Niosomes with Intestinal Cellular Monolayers

In vitro cell-based characterizationmethods ofnanoparticles are generally static and require the use of secondaryanalysis techniques and labeling agents. In this study, bare niosomesand chitosan-coated niosomes (chitosomes) and their interactions withintestinal cells are studied under dynamic conditions and withoutfluorescent probes, using surface plasmon resonance (SPR)-based cellsensing. Niosomes and chitosomes were synthesized by using Tween 20and cholesterol in a 15 mM:15 mM ratio and then characterized by dynamiclight scattering (DLS). DLS analysis demonstrated that bare niosomeshad average sizes of similar to 125 nm, polydispersity index (PDI) below0.2, and a negative zeta (zeta)-potential of -35.6 mV. Inturn, chitosomes had increased sizes up to similar to 180 nm, with aPDI of 0.2-0.3 and a highly positive zeta-potential of +57.9mV. The viability of HT29-MTX, Caco-2, and Caco-2/HT29-MTX coculturedcells showed that both niosomes and chitosomes are cytocompatibleup to concentrations of 31.6 mu g/mL for at least 240 min. SPRanalysis demonstrated that chitosomes interact more efficiently withHT29-MTX, Caco-2, and Caco-2/HT29-MTX cocultures compared to bareniosomes. The resulting SPR measurements were further supported byconfocal microscopy and flow cytometry studies, which demonstratedthat this method is a useful complementary or even alternative toolto directly characterize the interactions between niosomes and in vitro cell models in label-free and real-time conditions.