The sPHENIX experiment will study the QGP properties with heavy bottom quark jets (b-jets) produced in high-energy heavy ion collisions, in the challenging low-pT regime, where the expected mass-dependence effects are large but the underlying backgrounds are also high. Key to identifying such jets is the 3-layer Monolithic-Active-Pixel-Sensor(MAPS) based vertex detector, originally developed for the ALICE ITS upgrade. The MVTX will serve as the innermost component of the sPHENIX tracking system, covering 2 cm to 4 cm radially and a pseudorapidity range of |η| < 1.1. Although it uses the same sensor elements and basic geometry, many aspects of the mechanical systems had to be adapted from the original ALICE versions. We present the current status of the detector design, highlighting the changes made to integrate the MVTX into the sPHENIX detector.