Based on previously reported dual encapsulation strategy, we present a systematic investigation of incorporating Tris(bipyridine)ruthenium(II) ([Ru(bpy)3]2+) into amphiphilic polymer particles post-polymerisation. Using [Ru(bpy)3]2+ as a model probe due to similar water solubility and similar chemical structure, we study the key parameters controlling probe encapsulation in core-shell particles comprising polymethyl methacrylate (PMMA) core and polyoligoethylene glycol methyl ether methacrylate p(OEGMEM) shell. The particles undergo swelling with MMA to enhance probe uptake, with increased loading efficiency compared to unswollen particles. Our work focuses on establishing a well-controlled, reproducible method for creating stable responsive hydrogel sensors, with investigation on how particle characteristics, particularly p(OEGMEM) shell length, influence probe retention and subsequent incorporation into HEMA-based hydrogels.