1. Determining vitreous viscosity using fluorescence recovery after photobleaching.
- Author
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Srikantha N, Teijeiro-Gonzalez Y, Simpson A, Elsaid N, Somavarapu S, Suhling K, and Jackson TL
- Subjects
- Animals, Bevacizumab chemistry, Bevacizumab metabolism, Dextrans chemistry, Diffusion, Ficoll chemistry, Fluorescein-5-isothiocyanate analogs & derivatives, Fluorescein-5-isothiocyanate chemistry, Ranibizumab chemistry, Ranibizumab metabolism, Receptors, Vascular Endothelial Growth Factor chemistry, Receptors, Vascular Endothelial Growth Factor metabolism, Recombinant Fusion Proteins chemistry, Recombinant Fusion Proteins metabolism, Serum Albumin, Bovine chemistry, Swine, Viscosity, Fluorescence Recovery After Photobleaching methods, Vitreous Body metabolism
- Abstract
Purpose: Vitreous humor is a complex biofluid whose composition determines its structure and function. Vitreous viscosity will affect the delivery, distribution, and half-life of intraocular drugs, and key physiological molecules. The central pig vitreous is thought to closely match human vitreous viscosity. Diffusion is inversely related to viscosity, and diffusion is of fundamental importance for all biochemical reactions. Fluorescence Recovery After Photobleaching (FRAP) may provide a novel means of measuring intravitreal diffusion that could be applied to drugs and physiological macromolecules. It would also provide information about vitreous viscosity, which is relevant to drug elimination, and delivery., Methods: Vitreous viscosity and intravitreal macromolecular diffusion of fluorescently labelled macromolecules were investigated in porcine eyes using fluorescence recovery after photobleaching (FRAP). Fluorescein isothiocyanate conjugated (FITC) dextrans and ficolls of varying molecular weights (MWs), and FITC-bovine serum albumin (BSA) were employed using FRAP bleach areas of different diameters., Results: The mean (±standard deviation) viscosity of porcine vitreous using dextran, ficoll and BSA were 3.54 ± 1.40, 2.86 ± 1.13 and 4.54 ± 0.13 cP respectively, with an average of 3.65 ± 0.60 cP., Conclusions: FRAP is a feasible and practical optical method to quantify the diffusion of macromolecules through vitreous., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2022
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