Electrochemically differentiated human MSCs biosensing platform for quantification of nestin and β-III tubulin as...

Polydimethylsiloxane (PDMS) on ITO substrate was used to create a well with conducting surface to adhere human mesenchymal stem cells (hMSCs) and provide electrochemical stimulation for inducing their differentiation into neural-like cells. The cells that received electrochemical stimulation did not show any noticeable change in their viability and proliferation. The cell morphology of the differentiated hMSCs adherent on ITO showed outgrowth and elongation in one dimension, resembling neural-like cells. Immunocytochemistry assessment by quantifying the expression of nestin and β-III tubulin also confirmed the differentiation of hMSCs. These differentiated hMSCs adherent on ITO were used as electrochemical biosensing platform for differential pulse voltammetry (DPV) measurement for selectively quantifying cell surface markers expressed by neural stem cells and mature neurons. The variation of nestin antibodies concentrations from 9 μU to 27 μU showed a linear increase in DPV current with a detection sensitivity of ∼28 nA/μU of antibody. Varying concentrations of β-III tubulin antibodies from 30 μU to 210 μU showed a linear increase in DPV current with a detection sensitivity of ∼2.0 nA/μU of antibody. The highest expression level of cell surface marker corresponding to β-III tubulin in total adherent cells on ITO was calculated. It was in the order of 10^-8 U of antibodies/cell, representing the total population of mature neuron cells. This new way of detection may rapidly assess the quantitative expression of cell surface markers/antigens.