A marker-free cell imaging screening method based on digital holographic microscopy

Quantitative phase digital holographic microscopy (QP-DHM) we have developed presents the great advantage, thanks in particular to its numerical capacity to apply both wave front correction and autofocusing, to accurately measure optical path difference (OPD) in screening mode involving multiwell cell culture plates. Experiments combining electrophysiology and QP-DHM have permitted to establish relationships between ions movements (transmembrane current) and the OPD signal. The capacity of QP-DHM to perform label-free image-based screening was validated by screening for the GABAA receptor activity expressed in HEK cells using a selection of active compounds in agonist, antagonist, and modulator modes.