Project Summary Bone regenerative biomaterials are of critical importance in treatment of bone defect, enhanced bone healing, reduction of pain and disability, replacement of damaged or diseased bone, and development of new orthopedic treatment options among others. With many years of endeavors, the field of orthopedic regenerative biomaterials has seen tremendous progress, but many challenges remain. For instance, the currently available bone regenerative biomaterials are featured with inabilities to mimic the native tissue composition, and slow bone regeneration among others. The goals of this proposal are to elucidate an unexplored synergistic optoelectrostimulation and metabonegenic regulation for bone development, and to translate these understandings towards the design of novel biomimetic optoelectroactive citrate-presenting bone biomaterials for orthopedic applications for promoted bone repair. The proposed optoelectroactive citrate biocomposites (OCBs) that will enable synergistic osteopromotive effects between exogenous citrate supplement and in situ electrostimulation by wireless untethered photo-illumination to provide increased cellular energy supply in osteodifferentiated stem cells, as referred to a novel strategy of optoelectro-metabonegenic regulation. The OCBs will allow for citrate release in a control rate and in situ optoelectrostimulation through µ-solar cell pellets, where the µ-solar cell pellets will also be designed to be biodegradable to match the time frame of bone regeneration.