Molecular diagnostics based on smart phone

This study shows a valuable impact of the complementary metal oxide semiconductor (CMOS) image sensor and indium nanoparticle (InNP) substrates used for the detection of antigen-antibody interactions. Dielectric layer of antigen-antibodies bind on the conducting metal surface, which is helpful for the scattering of electro magnetic radiation. Different types of antigens such as Interferon Gamma, C-reactive protein and Troponin I were adsorbed on the InNP substrate and interact with specific antibodies. The antigen-antibody detection was based on the photon count measurements before and after protein binding observed by CMOS image sensor, which is converted into digital form with the help of analog to digital converter (ADC). Various thickness of InNP substrates were analyzed for antigen-antibody interaction. The photon counts gradually decrease when subsequent protein layers adsorbed on the substrates. This photon number is directly proportional to the digital number observed with the CMOS sensor for detecting antigen-antibody interactions.