Thermoresponsive Complex Coacervates as Advanced Carriers for Cell‐Laden Liquid‐Core Capsules for Biomedical Applications

ABSTRACT Injectable “smart” materials are emerging as promising platforms for minimally invasive cell delivery and tissue regeneration. A novel thermoresponsive complex coacervate was engineered through electrostatic interactions between natural polysaccharides grafted with poly( N ‐isopropylacrylamide) (PNIPAAm). The resulting biopolymeric‐derived coacervate exhibits pronounced shear‐thinning behavior and undergoes a rapid sol–gel transition at physiological temperature. Rheological analysis revealed that the thermoresponsive PNIPAAm chains regulate network dynamics, with faster relaxation at 25°C and enhanced structuring at 37°C due to increased hydrophobic interactions. The designed complex coacervate provides an efficient transport vehicle for the in situ retention of liquid‐core capsules (LC) loaded with human adipose stem cells, promoting autonomous and hierarchical tissue organization. This system retained its shear‐thinning properties even at high LC volumetric ratios (up to 54%) and supported high cell viability at least for 7 days. This strategy enables cell encapsulation in a thermoresponsive injectable complex coacervate that can be loaded with virtually any, or even multiple, cell types, offering a highly modular and cytocompatible platform. Altogether, this work introduces a new paradigm for the design of bioinspired, thermoresponsive complex coacervates, offering hierarchical control over cellular organization enabling the decoupling of tissue‐forming units from the transport matrix.