Biodegradable GdPO4·H2O/PLGA microcarriers for stem cell delivery and non-invasive MRI translocation tracing

Within brain tissue engineering, stem cell implantation assisted by biodegradable injectable scaffolds is a crucial method. However, implanted scaffolds, especially microcarriers, may translocate due to the fluidity of the materials. Therefore, the development of an MRI contrast enhancement microcarrier, which could noninvasively trace the location of the implant in vivo, is necessary to guide the evaluation of treatment prognosis. In this study, GdPO 4 ·H 2 O nanoparticles were utilized as the dispersed phase to endow PLGA microcarriers with T1-weighted MRI contrast ability. By adjusting the dispersed phase of Gd compound nanoparticle in PLGA Matrix, a cross-comparison experiment between MRI contrast enhancement imaging and biocompatibility was conducted, and 0.8% Gd was found to be the most suitable rate for preparing nano-composites. Moreover, 0.8% Gd/PLGA microcarriers were suspension-cultured with stem cells in vitro and implanted into traumatic brain injury rats in vivo. Excellent cytocompatibility and enhancement of the T1 phase of MRI were confirmed. This work created a T1-weighted MRI contrast-enhanced microcarrier, which provides a clinical noninvasive tracing cell scaffold for brain tissue engineering.