Figure 4.
Microfluidic platform for enhanced single-molecule FRET detection (adapted from reference 73: Lemke et al., J. Amer. Chem. Soc., 2009, 131: 13610–13612).
(A) A laminar-flow mixer can remove denaturant or add binding partner to trigger folding events. (B) Large channels ventilated by nitrogen flank the channels containing buffers and proteins, efficiently removing oxygen from the solution before mixing. (C) smFRET histograms obtained with the device, showing (i) the folding of T4 lysozyme proteins upon removal of guanidinium chloride, (ii) the radical improvement of data upon deoxygenation for data from a near IR-dye (Alexa750) and (iii) for T4 lysozyme proteins labeled by using an unnatural amino-acid strategy.