Invited Paper
Mid-IR Plasmonics for Time-Resolved and Ultra-Sensitive Vibrational Biospectroscopy

Hatice Altug Bioengineering Department, EPFL, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland Dordaneh Etezadi Bioengineering Department, EPFL, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland Odeta Limaj Bioengineering Department, EPFL, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland Daniel Rodrigo Bioengineering Department, EPFL, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland Ronen Adato Electrical Engineering, Boston University, Boston, Massachusetts, USA Arif Cetin Bioengineering Department, EPFL, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland

We will present a plasmonic-fluidic technology performing real-time and ultra-sensitive Mid-Infrared (Mid-IR) absorption spectroscopy in aqueous environment by directly accessing distinct chemical fingerprints of biomolecules. We will demonstrate that the technology is uniquely capable of monitoring biomolecular kinetics of protein-protein interactions and real-time formation of biomimetic cell membranes without any external labels. In leveraging engineered plasmonic antennas for Mid-IR absorption enhancement, our results represent a dramatic advance over previous studies, being the first demonstration of their use for biologically significant measurements in solution. We will also introduce recent advancements for engineering plasmonics substrates and using new materials to increase overlap between biomolecules and near-fields, thus absorption signals.

Measuring kinetic reactions and performing in-situ measurements are fundamentally challenging in traditional Mid-IR spectroscopy due to sensitivity limitations and the extremely strong absorption bands of liquid water. Our plasmonic system overcomes these challenges by exploiting extreme confinement of near-field enhancements at the sensor chip interface. Compared to traditional label-free approaches our technology is based on molecular bond-specific Mid-IR absorption signatures, therefore it even enables observation of minute volumes of water displacement during molecular interactions. These measurements are made possible by the plasmonic enhancement of absorption bands in conjunction with a non-classical form of internal reflection that together boost sensitivity while limiting interference from solution absorption. In comparison with the current state of the art in Mid-IR spectroscopy, we reduce the sampling volumes more than three orders of magnitude and eliminate the need for bulky and macroscopic optics. Our ultra-compact chip based technology integrated with microfluidics represents a dramatic advancement in the compatibility of Mid-IR absorption spectroscopy with modern and next generation sample preparation and handling techniques.

hatice.altug@epfl.ch









Powered by Eventact EMS