Characterization of Stem Cell-Laden Nanocomposite Hydrogels for Injectable Therapy.

Hydrogels are widely used as injectable biomaterials for minimally invasive stem cell delivery, providing a hydrated three-dimensional matrix that supports cell survival and retention. Nanocomposite hydrogels, formed by combining hydrogels with nanoscale fillers, offer additional opportunities to tailor rheological behavior and mechanical performance for injectable cell-delivery applications. However, their translational potential depends on the ability to rationally characterize both material behavior and cell compatibility under injection-relevant conditions. This chapter presents a structured experimental protocol for the preparation and initial characterization of collagen-Laponite nanocomposite hydrogels containing human adipose-derived mesenchymal stem cells as a representative model for injectable therapeutic applications. The protocol describes hydrogel formulation, nanoparticle dispersion, stem cell encapsulation, rheological characterization, injectability testing, post-injection viability assessment, and short-term metabolic activity analysis. Although a collagen-Laponite formulation and human adipose-derived mesenchymal stem cells are used as the working example, the protocol provides a practical and systematic framework for evaluating injectable stem cell-laden nanocomposite hydrogels, with particular focus on balancing injectability, structural integrity, and preservation of cellular function.