We present a one-step method to fabricate microparticles to detect substances and release drugs in our bodies. Our microparticles have two compartments and an outer shell. The two compartments (Janus cores) enable the encapsulation of different materials separately for diagnosis and therapy while the outer shell reduces the adhesion and protects the encapsulated materials. These multi-functional core-shell Janus microparticles are fabricated by simply ejecting pre-gel solutions into a calcium chloride solution under centrifugal gravity application and UV irradiation. Moreover, we implanted these microparticles in biological tissue and demonstrated the transdermal sensing and drug model release. We believe that our fabrication method and particle design could be an effective approach for multi-functional smart theranostic medicine.