Diffusion of protein through the human cornea

Area of Science:

• Biomedical Engineering
• Ophthalmology
• Pharmacology

Background:

• The human cornea acts as a barrier, influencing drug delivery to the anterior eye.
• Understanding protein diffusion across the cornea is crucial for developing novel ophthalmic therapies and artificial cornea technologies.

Purpose of the Study:

• To quantify the diffusion rates of myoglobin (4.4 nm) and bovine serum albumin (BSA, 7.2 nm) through ex vivo human corneas.
• To assess the potential for passive diffusion of larger molecules across the corneal barrier.

Main Methods:

• Diffusion coefficients were measured using a diffusion chamber with ex vivo human corneas separating protein solutions from balanced salt solution.
• Protein concentrations were monitored over time, and diffusion coefficients were calculated using Fick's law and conservation of mass principles.

Main Results:

• The diffusion coefficient for myoglobin was determined to be 5.5 ± 0.9 × 10(-8) cm(2)/s.
• The diffusion coefficient for BSA was found to be 3.1 ± 1.0 × 10(-8) cm(2)/s.

Conclusions:

• The human cornea permits passive diffusion of molecules as large as 7.2 nm (BSA).
• These findings suggest potential for enhanced corneal drug delivery and inform the design of artificial corneas.
• Further research is necessary to explore the full extent of corneal diffusion and its clinical applications.