Selective two-photon collagen crosslinking in situ measured by Brillouin microscopy


Kwok SJJ, Kuznetsov IA, Kim M, Choi M, Scarcelli G, and Yun SH. 5/4/2016. “Selective two-photon collagen crosslinking in situ measured by Brillouin microscopy.” Optica, 3, 5, Pp. 469-472. Publisher's Version


Two-photon polymerization has enabled precise microfabrication of three-dimensional structures with applications spanning from photonic microdevices, drug delivery systems, and cellular scaffolds. We present two-photon collagen crosslinking (2P-CXL) of intact corneal tissue using riboflavin and femtosecond laser irradiation. Collagen fiber orientations and photobleaching were characterized by second harmonic generation and two-photon fluorescence imaging, respectively. Measurement of local changes in longitudinal mechanical moduli with confocal Brillouin microscopy enabled the visualization of the cross-linked pattern without perturbation of the surrounding non-irradiated regions. 2P-CXL induced stiffening was comparable to that achieved with conventional one-photon CXL. Our results demonstrate the ability to selectively stiffen biological tissue in situ at high resolution with broad implications in ophthalmology, laser surgery, and tissue engineering.
Last updated on 02/08/2018