100 likes | 591 Views
Shachar Tauber, M.D. Tauber, S. 1,2 , Smith, N. D. 2 , Davis, K. E. 1,2 , Wnek, G. E. 3 , Fuerst, R. 2,4 , Bango, J. J. 2,5. 1 St. John’s Medical Research Institute, St. John’s Health System, Springfield, MO 2 Jordan Valley Innovation Center, Missouri State University, Springfield, MO
E N D
Shachar Tauber, M.D. Tauber, S.1,2, Smith, N. D.2, Davis, K. E.1,2, Wnek, G. E.3, Fuerst, R.2,4, Bango, J. J.2,5 1St. John’s Medical Research Institute, St. John’s Health System, Springfield, MO 2Jordan Valley Innovation Center, Missouri State University, Springfield, MO 3Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 4Pacific Laser Eye Center, Sacramento, CA 5Connecticut Analytical Inc., Bethany, CT
Shachar Tauber, Randall Fuerst, and Joseph Bango have financial interests. • Electrospun materials used in this study have not been approved by the FDA.
Fabricate an electrospun poly(vinyl alcohol) material for use as a contact lens • Compare electrospun PVA and commercially available Ciba Vision® Focus® DAILIES® contact lenses composed of the polymer nelfilicon A (PVA partially acetalized with N-formylmethyl acrylamide) in terms of: • Water Content • Oxygen Permeability • Optical Transmittance • Index of Refraction
Electrospinning is a technique of producing polymer micro- and nanofiber non-woven mats of varying thicknesses. • Applications in medicine include: • Scaffolds for wound healing and tissue regeneration • Matrices for the controlled release of therapeutic molecules • Medical device coatings • Electrospinning is a versatile technique applicable to a wide range of polymers and solvents. • This versatility coupled with the ability to control the porosity of electrospun mats suggests the opportunity for selected electrospun polymers to parallel or surpass characteristics of current contact lens materials. • Prospects of fabricating contact lenses using electrospinning technology may lead to extended wear contact lenses for visual and therapeutic applications.
The polymer poly(vinyl alcohol), PVA, has been selected for evaluation based on the ease of electrospinning from aqueous solutions, the opportunity for physical and/or chemical crosslinking, and established applications of PVA in the contact lens industry. • A solution of 10 wt% PVA, 2 wt% Triton X-100, and deionized water were electrospun resulting in a non-woven mat of PVA nanofibers. • The mats were then physically crosslinked by soaking in a methanol bath for several hours and dried by evaporation before hydrating with a saline solution conforming to ISO 18369-3:(2006)E. • Electrospun materials were compared to the commercially available Ciba Vision® Focus® DAILIES® Visitint composed of the polymer nelfilicon A (PVA partially acetalized with N-formylmethyl acrylamide).
Visual Material Comparison • Hydration of Electrospun PVA Material Figure 1. (a) Focus Dailies® Visitint, Power: -1.25, BC: 8.6, Diameter: 13.8 mm, Expiration date: 2012/03, 31% nelfilcon A, 69% water. (b) Electrospun PVA (10 wt%). b a Figure 2. Left: Dry electrospun PVA mat (10 wt%). Right: Electrospun PVA mat hydrated in saline.
Atomic Force Microscopy • Scanning Electron Microscopy b a Figure 1. (a) Focus Dailies® Visitint, Power: -1.25, BC: 8.6, Diameter: 13.8 mm, Expiration date: 2012/03, 31% nelfilcon A, 69% water. Scan size 5 µm, 150 nm scale. (b) Electrospun PVA (10 wt%). Scan size 50 µm, 6.5 µm scale. Figure 2. (a) Focus Dailies® Visitint, Power: -1.25, BC: 8.6, Diameter: 13.8 mm, Expiration date: 2012/03, 31% nelfilcon A, 69% water. (b) Electrospun PVA (10 wt%). b a
This pioneering study shows it is possible to reproduce many of the key features of commercially available contact lenses, specifically water content and oxygen permeability. • Index of refraction, while different, may be related to modifications to polymer formulations. Same index of refraction is believed to be achievable with alternations of PVA formulation. • Oxygen transmissibility is presently suboptimal; ongoing research is investigating theoretic models for optical clarity. • Electrospun PVA demonstrates reproducible void spaces shown by scanning electron and atomic force microscopy.
Electrospun nanofibers represent an exciting new avenue for contact lens and cornea surgery. • Our early work shows it is possible to reproduce many of the properties of modern contact lenses. • The reproducible void spaces in electrospun PVA may allow for sequestering of pharmaceutical agents as well as the potential for self-cleaning. • Please see our Electrospun Nanofibers: Advances in Biomaterials for Contact Lenses and Artificial Corneas video ASCRS 2008 and Electrospun Polymers in Cornea Repair and Regeneration poster presented at ARVO 2008.