Development of a portable spectrophotometer for the detection of upconversion nanoparticle

Luminescence particles are very important in analysis or in a variety of other applications like environmental sensing, biological imaging and disease diagnosis to name but a few. UCNP is capable of changing near-infrared excitation to visible light emissions referred to as anti-Stokes luminescence. This minimizes the interference of the natural autofluorescence in biological samples. The ease of penetration into the samples and their depth by the fluorophores, in addition to the fact that the particles are chemically stable and thus superior to traditional fluorophores. In order to expand the use of UCNP applications to non-controlled lab environments, an increasing demand exists in the provision of compact user-friendly instrumentation. A portable spectrophotometer optimally designed to measure UCNP quantitatively was developed in this study. The machine has a safe zone having special lid enclosure to keep the cuvette containing UCNP solution. The enclosure blocks all the light when it is closed, which prevents the measurements of the enclosure against external influences. It has a TSL2591 light sensor to measure the emitted luminescence and a fiber optic connection to excite the UCNPs with a 980 nm near-infrared laser beam with a 500 mW power output. Wireless communication is offered with the help of a router linked to a developed Android application. This application enables one to handle materials, calibrate device, trade in data, and plot correlation and calibration curves. Tests done following calibration indicated a R2 value of 0.76 and 0.839 between computed and experimental values of UCNP.