Novel versatile smart phone based Microplate readers for on-site diagnoses

Microplate readers are important diagnostic instruments, used intensively for various readout test kits (biochemical analysis kits and ELISA kits). However, due to their expensive and non-portability, commercial microplate readers are unavailable for home testing, community and rural hospitals, especially in developing countries. In this study, to provide a field-portable, cost-effective and versatile diagnostic tool, we reported a novel smart phone based microplate reader. The basic principle of this devise relies on a smart phone's optical sensor that measures transmitted light intensities of liquid samples. To prove the validity of these devises, developed smart phone based microplate readers were applied to readout results of various analytical targets. These targets included analanine aminotransferase (ALT; limit of detection (LOD) was 17.54 U/L), alkaline phosphatase (AKP; LOD was 15.56 U/L), creatinine (LOD was 1.35 μM), bovine serum albumin (BSA; LOD was 0.0041 mg/mL), prostate specific antigen (PSA; LOD was 0.76 pg/mL), and ractopamine (Rac; LOD was 0.31 ng/mL). The developed smart phone based microplate readers are versatile, portable, and inexpensive; they are unique because of their ability to perform under circumstances where resources and expertize are limited.