Hybrid quantum dot - collagen extracellular matrices for in situ optical monitoring of cardiomyocyte activity by two-photon fluorescence

ABSTRACTThe incorporation of functional nanoparticles in scaffolds for tissue constructs has led to the creation of artificial extracellular matrices that more accurately mimic the cues present in the native microenvironment of developing tissue. Additionally, light-sensitive inorganic nanoparticles can act as cell biosensors and report on the physiological parameters during tissue growth and organization. In this work, we functionalized collagen nanofibers with semiconductor quantum dots (QDs) and thereby created artificial extracellular matrices that can optically report on cardiomyocyte activity based on QD two-photon fluorescence. We have applied these optically-addressable nanofiber matrices to monitor activities of primary cardiomyocytes and compared the optical responses with patch-clamp data. Combining the long-term stability of QD fluorescence with the deeper light penetration depths achievable through multiphoton imaging, this approach can be used for continuous monitoring of cellular functions in cardiac tissue engineering.Abstract FigureConcept illustration: optical readout of cardiomyocyte activity with QD-functionalized collagen networks. Whole-cell current-clamp mode is used here to simultaneously monitor changes in the transmembrane voltage while the QD two-photon fluorescence is recorded.