This image are part of a project to develope injectable, microsphere-based vascularized niches for image-guided delivery of hepatocytes, enabling cell self-assembly within the voids between microspheres and real-time ultrasound guidance for placement and monitoring.By engineering the “negative space”, the interconnected voids formed between the microspheres, the system intentionally shapes pore size, connectivity, and confinement to guide self-assembly, polarization, and cell migration. Fibroblasts contribute extracellular matrix proteins and paracrine factors that support hepatocyte viability and promote tissue remodeling.