A SU-8 fluidic microsystem for biological fluids analysis

Abstract

This paper describes a fluidic microsystem fabricated in SU-8 epoxy photoresist suitable for on-chip liquid handling and mixing. The application is the concentration measurement of biomolecules in biological fluids, such as urine, blood, serum, plasma or cerebrospinal fluid. In general, fluidic microsystems on glass are fabricated using HF acid etching techniques, which requires careful handling, or using micromilling, which gives high-roughness surface. The SU-8 fabrication process is low-cost, biocompatible and UV lithography semiconductor compatible. It requires neither complex techniques nor expensive masks and is suitable for batch production. Moreover, SU-8-based processing enables the fabrication of deep microchannels with very low sidewall roughness, which is suitable, when it is used an optical absorption measurement method. The high light of this paper is the implementation of a fluidic microsystem for biological fluids analysis with SU-8 photoresist. The fluidic microsystem performance is successfully demonstrated in the spectrophotometric measurement of total protein concentration in urine, by optical absorption.