Sensitive,　accurate,　and　straightforward　biosensors　are　pivotal　in　the　battle　against　Alzheimer＇s　disease,　particularly　in　light　of　the　escalating　patient　population.　These　biosensors　enable　early　adjunctive　diagnosis,　thereby　facilitating　prompt　intervention,　alleviating　socioeconomic　burdens,　and　preserving　individual　well-being.　In　this　study,　we　introduce　the　development　of　a　highly　sensitive　add-drop　dual-microring　resonant　microfluidic　sensing　chip　boasting　a　sensitivity　of　188.11　nm/RIU,　marking　a　significant　20.7%　enhancement　over　single　microring　systems.　Leveraging　ultra-thin　Parylene　C　for　streamlined　antibody　immobilization　and　non-destructive　removal,　this　platform　facilitates　the　precise　quantification　of　the　Alzheimer＇s　disease　biomarker　Aβ42.　Employing　an　immune　sensing　strategy　that　amplifies　and　captures　antigen　signals　using　Au-labeled　antibodies,　we　achieve　an　exceptional　limit　of　detection　of　9.02　pg/mL.　The　designed　microring-based　microfluidic　biosensor　chip　exhibits　outstanding　specificity　and　sensitivity　for　Aβ42　in　serum　samples,　offering　a　promising　avenue　for　the　early　adjunctive　diagnosis　of　Alzheimer＇s　disease.　©　2024　Elsevier　B.V.