Nonlinear optical microspectroscopy of biochemical interactions in microfluidic devices
Additional Document Info
2009 by Taylor & Francis Group, LLC. The ability to manipulate fluids in channels with dimensions of tens of micrometers and less has revolutionized biology and chemistry in the same way the invention of the integrated circuit by Kilby and Noyce in the 1950s spawned the progress of microelectronics. This fast developing area of science and technology, called microfluidics, finds more and more applications ranging from chemical analysis to biological and chemical microreactors, replacing bulky devices and sparking new applications (Hansen and Quake 2003; Whitesides 2006). However, the progress of science depends on the development of new tools and instruments capable of realtime molecular-level imaging. Our ability to monitor in situ the transitional changes of chemical and structural composition becomes an important issue for the continuing advancement and successful implementation of this new technology, directing its manufacturing and exploring the new areas of its applications (Viskari and Landers 2006). This chapter discusses the development of an innovative photonics toolbox, which aims at addressing both the structural and chemical analysis in situ of liquids and living cells in microfluidic devices. These new photonic tools include optical harmonics generation and nonlinear Raman microscopy, which perfectly match the space and time scales of the processes in microfluidic channels. Due to their intrinsic noninvasiveness, strong signal level, and unsurpassing chemical and structural sensitivity, they have great potential to become indispensable methods for detecting chemical and structural variations across and along the microfluidic channel, for in vivo analysis of living cells development, for noninvasive chemical recognition, and for in situ monitoring of chemical reactions. These tools can be combined with more traditional light absorption and scattering measurements.