We present here some miniaturised devices designed for the detection of nanorods in water and blood media. The devices use light emitting diodes as monochromatic light sources and Si photodiodes for detection. Devices working on transmission mode are able to detect nanorods concentration below micrograms/litre. Sensitivity is reduced is one or of magnitude for nanorods in blood. We show detection of low nanorods concentration with devices working in reflection mode, opening the possibility to perform direct imaging of nanorods in vivo. The optima condition for detection and resolution limits are also discussed.