Additional file 1: Figure S1. of Exogenous marker-engineered mesenchymal stem cells detect cancer and metastases in a simple blood assay

Firefly and humanized Gaussia luciferases are substrate-specific and not cross-reactive. hGluc-MSCs, Fluc-tdT-MSCs (Fluc-MSCs), and N-MSCs were seeded in 96-well plate. The firefly luciferase substrate D-luciferin (final concentration = 150 μg/ml) or the humanized Gaussia luciferase substrate CTZ (final concentration = 20 μM) was added, and luciferase activity was measured with a plate reader. Error bar: mean ± standard deviation. Exposure time = 2 s. A.U. arbitrary units, CTZ coelenterazine, Fluc firefly luciferase, hGluc humanized Gaussia luciferase, MSC mesenchymal stem cell, tdT tdTomato red fluorescent protein. (PNG 37 kb