Absorption and fluorescence spectroscopic analysis using compact, linear variable filter based, detection platforms

Abstract

Spectroscopic analysis is an integral part of biological and chemical sensing. However, most spectroscopic equipment is relegated to laboratories. Compact and portable alternatives to conventional spectroscopic tools allow for testing outside of laboratory settings. This is achieved by making the underlying equipment affordable and easy to use while preserving reasonable accuracy and sensitivity. Due to their ubiquity, and constantly improving hardware and software, smartphones represent a favorable candidate for integration with spectroscopic technologies. This work presents the design, fabrication and characterization of compact measurement platforms capable of both absorption and fluorescence spectroscopic analysis using linear variable filters (LVF). The platform's potential for integration into next generation smartphones is demonstrated by the use of a conventional CMOS image sensor in conjunction with the LVF to create the detection element. An LVF-based benchtop detection setup is initially presented followed by its miniaturized successors: compact absorption and fluorescence detection platforms. A series of tests is discussed, most notably an enzyme-linked immunosorbent assay used to measure concentrations of human fetal fibronectin, a predictor of preterm birth, as a real-world contextualization of the absorption platform.