Mechanical and Optical Properties of PCL Nanofiber Reinforced Alginate Hydrogels for Application in Corneal Wound Healing
Treatment of corneal wounds in ophthalmology often involves the application of biological membranes, especially human amniotic membranes. As result of the biological background optical and mechanical properties can be inconsistent. Additionally, there is a huge need for serological screening to avoid transmission of diseases from donors. To replace the amniotic membrane we prepared nanofiber hydrogel compounds and evaluated their application-relevant properties. Nanofibers were prepared of polycaprolactone (PCL) and a blend with chitosan (CHI) by electrospinning. Nanofiber webs were produced either random, without specific orientation, or as multilayer webs of aligned fibers, where adjacent layers have a perpendicular fiber orientation to each other (aligned). Different treatment methods were evaluated for PCL scaffolds to decrease the water contact angle to obtain wettable membranes. The resulting nanofiber matrices were used to reinforce alginate hydrogels and thus to obtain scaffolds to replace the amniotic membrane as wound closure material for the cornea. We, therefore, investigated the transparencies of the manufactured compounds by UV-Vis spectroscopy and the readability through the membranes. As these membranes are to be sutured onto wounds, especially a human cornea, mechanical resistance against suture pullout was evaluated by suture retention test (SRT). Our results show the feasibility of producing nanofiber hydrogel compounds of pretreated PCL or blended PCL/CHI nanofibers and alginate hydrogel. All materials show high transparencies while only random nanofiber reinforced hydrogels showed increasing resistance to suture pullout. Reproducible compounds can be obtained in a quick, easy and inexpensive procedure maintaining properties that can be adjusted to the needs. Our membranes with random nanofiber scaffolds are able to mimic the properties of amniotic membranes, confirming their potential as the replacement application as wound cover material for the cornea.