One of the premises of the so called lab-on-a-chip paradigm is the integration of as many as possible processing stages of a chemical or biochemical analytical procedure together with microfluidics and detection methods. This latter aspect entails reliability, sensitivity and specificity of the analytical systems. Although electrochemical and mechanical approaches are common, optical detection remains predominant, mainly because its non-invasiveness, its high sensitivity and its small footprint. In this respect, many research groups – including our own – have concentrated their efforts in developing photonic lab-on-a-chip (PhLoC), where many different microoptical and photonic elements are monolithically integrated together with microfluidic devices.

Amongst the many applications to which these systems have been dedicated, cell culture has been identified as having great potential for improving throughput and reliability though miniaturization. In this seminar we will firstly, introduce the microoptical elements required to define PhLoC. Then, as a main example of such systems, it will be introduced the multiple internal reflection (MIR) systems, where simultaneous scattering and absorbance measurements can be performed. Key aspects in both PhLoC such as multiparametrical analysis, sensitivity, limit of detection, and growth rate will also be discussed. In the second part of this seminar, we will start discussing more advanced configurations such as the Dual Lab on a Chip (DLOC) that enables simultaneous optical and electrochemical detection working in continuous flow regime. Both detection modes are integrated for the first time into a single detection volume and operate simultaneously with no evidence of cross-talk. Such system was applied to the analysis of L-lactate via a bi-enzymatic reaction involving lactate oxidase (LOX) and horseradish peroxidase (HRP). Here, the consumption of the reagent of the reaction (ferrocyanide) was continuously monitored by amperometry whereas the product of the reaction (ferricyanide) was recorded by absorbance. Finally, some insights regarding the twin biophotonic lab on a chip with integrated size-exclusion microfilters for simultaneous monitoring of cell retention, proliferation and metabolism will also be given.


Wednesday, February 20, 2013, 10:30. Seminar Room

Hosted by Dr. Susana Santos