Smartphone and Paper-Based Fluorescence Reader: A Do It Yourself Approach.

Given their photoluminescent character, portable quantum dot readers are often sophisticated and relatively expensive. In response, we engineered a "do it yourself" fluorescence reader employing paper materials and a mid-range smartphone camera. Black paperboard facilitated a versatile, lightweight and foldable case; whereas cellophane paper was observed to behave as a simple, yet effective, optical bandpass filter leading to an advantageous device for the quantitative interrogation of quantum dot nanocrystals concentrations (from 2.5 to 20 nM), which are suitable for optical point-of-care biosensing. The streptavidin-coated nanocrystals employed are commercially available and the developed reader was benchmarked with a standard portable quantum dot reader, thereby demonstrating advantages in terms of cost and linear analytical range.