Organ-on-a-chip (OOC) models, based on microfluidic technology, are valuable tools for studying human physiological and pathological processes and hold promise for drug development and regenerative medicine. However, conventional microfluidic devices face challenges such as inadequate representation of curved structures, stiffness of base materials compared to natural extracellular matrix, and difficulties in precise cell seeding. To address these issues, a new cell seeding technique involves pre-wrapping cells around sacrificial fiber templates to create more accurate circular cross-sectioned tubular OOC models. This approach was demonstrated with a renal proximal tubule-on-a-chip, which included branching and curvature, and an initial model of vascular-renal tubule interaction, showing potential for diverse applications in physiological and pathological studies.