Dual sensitivity-enhanced microring resonance-based integrated microfluidic biosensor for Aß42 detection.

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 Aß42. 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 Aß42 in serum samples, offering a promising avenue for the early adjunctive diagnosis of Alzheimer's disease.

Temperature-insensitive optical sensors based on two cascaded identical microring resonators.

We demonstrate a novel, to the best of our knowledge, temperature-insensitive optical sensor based on two cascaded identical microring resonators (CIMRR) in this Letter. The structural parameters of the reference ring and sensing ring are designed to be identical. The upper cladding in the sensing windows of the two rings is removed. With different microfluidic channels, the reference ring and sensing ring are exposed to the reference solution and reagent sample, respectively. For wavelength interrogation experiments in the transmission spectrum contrast ratio and low-cost intensity interrogation experiments, the sensitivities of refractive index (RI) sensing are 3402.4 dB/RIU and 1087.3 dB/RIU, respectively, while the temperature sensitivities are as low as 0.023 dB/K and 0.0124 dB/K, respectively.