Microfluidic-based non-enzymatic glycation enhances cross-linking of human scleral tissue compared to conventional soaking.

We evaluated nano-structural and chemical changes in human scleral collagen caused by non-enzymatic glycation using AFM, Raman spectroscopy, and microfluidics. Twenty 8 × 2 mm2 scleral strips (n = 5, each) were divided into four groups of pure sclera tissues (control group) and sclera tissues with incubation (1 hr in BSS and ribose) and preservation (23 hr in 90% ethanol) for 7 days (BSS + DR7 group) and 30 days (BSS + DR30 group) at room temperature, and 7 days in a microfluidic chip (BSS + DR + µF7 group). The BSS + DR7 and BSS + DR30 groups were incubated in a mixture of balanced salt solution (BSS) and 0.2 M D-ribose in PBS, pH 7.4 containing 0.1% sodium azide, while the BSS + DR + µF7 group was incubated in the same solutions supplied by two inlet reservoirs from a microfluidic chip. The scleral tissues incubated in the microfluidic environment showed a clear irregular parallel arrangement of collagen fibrils with tangled fibrils. A Raman shift was observed at 919 cm-1 in the glycation groups. Non-enzymatic glycation led to an increased in the density of scleral stromal collagen. Our method using non-enzymatic glycation in a microfluidic environment successfully induced collagen cross-linking. These in vitro results suggested that glycation can be used to strengthen connective tissues. SCANNING 38:421-426, 2016. © 2016 Wiley Periodicals, Inc.