The United States is currently experiencing an opioid crisis, with more than 47,000 deaths because of overdose in 2017. Current approaches for opioid identification and quantification in body fluids include immunoassays and chromatographic methods (e.g., LC-MS, GC-MS) which require expensive instrumentation and extensive sample preparation. Our aim is to develop a portable point-of-care device that can be used for instant detection of opioids in body fluids. Here, we report the development of a morphine-sensitive fluorescence-based sensor chip to sensitively detect morphine in blood using a homogenous immunoassay without any washing steps. Morphine-sensitive illuminating peptides were identified by a high throughput OBOC combinatorial peptide library approach. The OBOC libraries containing a large number of random peptides with a molecular rotor dye were screened for fluorescent activation under a confocal microscope as shown in figure 1. Using this novel three-step fluorescent screening assay, we were able to identify peptide-beads that fluoresce in the presence of anti-morphine antibody, but lost fluorescence when free morphine was present. Positive beads were then decoded using automatic Edman microsequencing, and the morphine-sensitive illuminating peptides were synthesized in soluble form, functionalized with an azido group, and immobilized onto microfabricated PEG-array spots on a glass slide. The sensor chip was then evaluated for detection of morphine in plasma. We have demonstrated that this proof-of-concept platform can be used to develop fluorescence-based sensors against morphine. More importantly, this technology can also be applied to the discovery of other novel illuminating peptidic sensors for detection of illicit drugs and cancer biomarkers in body fluids.