Biomimetic microfluidic systems incorporating photoswitchable building blocks
Florea, Larisa and Dunne, Aishling and Francis , Wayne and Diamond, Dermot (2015) Biomimetic microfluidic systems incorporating photoswitchable building blocks. In: COST Action MP 1205 Advances in Optofluidics: Integration of Optical Control and Photonics with Microfluidics , 7-8 May 2015, Porto, Portugal.
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Since the initial breakthroughs in the 1960’s and 70’s that led to the development of the glucose biosensor, the oxygen electrode, ion-selective electrodes, and electrochemical/optochemical diagnostic devices, the vision of very reliable, affordable chemical sensors and bio-sensors capable of functioning autonomously for long periods of time (years), and providing access to continuous streams of real-time data remains unrealized. This is despite massive investment in research and the publication of many thousands of papers in the literature. It is over 40 years since the first papers proposing the concept of the artificial pancreas, by combining the glucose electrode with an insulin pump. Yet even now, there is no chemical sensor/biosensor that can function reliably inside the body for more than a few days, and such is the gap in what can be delivered (days), and what is required (years) for implantable devices, it is not surprising that in health diagnostics, the overwhelmingly dominant paradigm for reliable measurements is single use disposable sensors. Realising disruptive improvements in chem/bio-sensing platforms capable of long-term (months, years) independent operation requires a step-back and rethinking of strategies, and considering solutions suggested by nature, rather than incremental improvements in available technologies.
Through developments in 3D fabrication technologies in recent years, we can build and characterize much more sophisticated 3D platforms than was previously possible. Furthermore also we can use hybrid materials – mixtures of organic and inorganic materials, create regions of differing polarity and hydrophobicity, mix passive and binding behaviours, regions of differing flexibility/rigidity, hardness/softness. In addition, we can integrate materials that can switch between these characteristics – selecting when and where these behaviours exist. In this paper we will present a series of examples of biomimetic microfluidic building blocks that exhibit photoswitchable characteristics such as programmed microvehicle movement, switchable binding and release, switchable actuation (e.g. valving), and photodetection. These building blocks can be in turn integrated into microfluidic systems with hitherto unsurpassed functionalities that can contribute to bridging the gap between what is required for many applications, and what we can currently deliver.
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