Bioanalytical Applications of Digital Imaging: Applications to Organ-on-chip and Point-of-care Analysis Systems

Qualitative and quantitative analysis through digital imaging has significant potential in several scientific applications including bioanalytical applications. In this document, the implication of digital imaging to validate and characterize a novel microfluidic organ-on-chip device and establish a point-of-care method to estimate epinephrine concentrations in expired and degraded autoinjectors have been described in chapter 2 and 3 respectively. Chapter 4 includes description of the principle and methodology of strong cation exchange-based immunoassay for oxytocin and β-endorphin.

In chapter 2, fabrication of a novel microfluidic organ-on-chip device capable of culturing rodent SCN slices has been discussed. Characterization of the aCSF media droplets and carbogen gas bubbles have also been discussed. Viability of the cultured rodent brain slices using digital imagery through fluorescence calcium imaging and PI/DAPI staining have been reported. In chapter 3, utilization of quantitative smartphone imaging to estimate the concentration of epinephrine in expired and degraded autoinjectors have been described. Actual concentrations of the samples have been established by UHPLC technique. The estimated concentrations of the samples via quantitative smartphone imaging have been reported to possess a strong correlation (r > 0.7) with the actual concentration. Different lighting conditions, distance and angle of camera variations have been explored in chapter 3.

Direct immunoassay of relatively small neurotransmitters (~1-5 KDa) through capillary electrophoresis is prone to poor resolution challenge. The principle of using strong cation exchange-based chromatography to carry out such immunoassays have been described in chapter 4. The possible use of crosslinking agents such as sulfo-GMBS and sulfo-SMPB to improve antigen-antibody binding has also been discussed in this chapter. Chapter 5 explores the future directions of improving the rodent slice culture device to accommodate various size and shape of brain slices by chamber geometry and surface energy optimization.