To enhance the biochemical binding on the unclad optical fiber, the find more information geometry of the grooved channel was the same as in our previous work . The grooves generate transverse flows in the microchannel  and enlarge the probability of analytes getting close to the immobilized receptors. Fabricating grooved microchannels (with a cross section of 500 ��m �� 500 ��m) can be quite complicated. An optical fiber composed of a silica core of 62.5 ��m in diameter was employed in the present study. In the original design as reported in the literature [1,2,5], the cladding and jacket layers of a 400 ��m core optical fiber were removed entirely. However, the mechanical strength of optical fiber with a core diameter of 62.5 ��m, as Inhibitors,Modulators,Libraries used herein, was not strong enough to sustain the stresses during assembling and packaging.
To avoid fracturing the fiber, the femtosecond laser was used to only partially remove the cladding and polymeric jacket. The present Inhibitors,Modulators,Libraries study presents a novel design of grooved fibers which have been integrated into the FO-LPR device. The designs of the grooved optical Inhibitors,Modulators,Libraries fibers, as illustrated in Figure 2, are termed as U-type or D-type based on the shape of the grooves.Figure 2.Dimensions and design of the grooved fibers. (a) U-type fiber. (b) D-type fiber.The length of one groove was Lg, and LS denotes the space between the grooves, which was fixed at 1 mm. The number of grooves (Ng) could be varied. In order to compare the performance of U-type and D-type fibers, the total effective area was fixed. Thus, the total length of the grooves was set at 6 mm, i.e.
, Ng �� Lg equals 6 mm. The mechanical strength of the optical fiber is expected to be improved because of the design of the grooves, and the grooves designed in the optical fiber are also expected to induce chaotic advection to enhance the mixing in the microchannel. The effect of the number of grooves (Ng) on biochemical binding was then investigated Inhibitors,Modulators,Libraries in this simulation study. The enhancement of not only mechanical strength, but also biochemical binding performance by chaotic mixing, is expected in the proposed design.3.?Experimental SectionA femtosecond laser micromachining system  was used for engraving grooves on the optical fiber. The femtosecond laser was a regenerative amplified mode-locked Ti:sapphire laser with pulse duration ~120 fs after the compressor, central wavelength 800 nm, repetition rate 1 kHz, and maximum pulse energy of ~3.
5 mJ. The number of laser shots applied to the sample was controlled by an Entinostat electromechanical shutter. The laser beam was focused further info onto the fiber by a 10x objective lens (numerical aperture 0.26, M Plan Apo NIR, Mitutoyo) mounted on a Z stage. Grooves under fabrication was translated by a PC controlled X-Y micro-positioning stage with error less than 1 ��m. The fabrication process was monitored by a charge-coupled device (CCD).