Label-free optical biosensors such as interferometers can provide comparable limit of detection to widely used enzyme-linked immunosorbent assays, while minimizing the number of steps and reducing false positives/ negatives. In 2020, authors reported a novel optofluidic Young interferometer (YI) that can provide real-time spatial information on refractive index changes occurring along the length of sensor and reference channels. Herein, we exploited these features of the YI to study interactions of biomolecules with recognition elements immobilized in selected regions of agarose gel in the sensor channel. We showed that the YI is well suited for biosensing of an exemplar biomolecule, streptavidin, in the absence and presence of bovine serum albumin interferent. Equally, we coupled the YI with electrokinetic transport to reduce the time for biosensing.