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Vol. 48, No. 1, 2012
Issue release date: June 2012
Free Access
Ophthalmic Res 2012;48:50–55
(DOI:10.1159/000329794)

Diffusion of Protein through the Human Cornea

Charalel R.A.a · Engberg K.b · Noolandi J.a · Cochran J.R.c · Frank C.b · Ta C.N.a
aDepartment of Ophthalmology, Byers Eye Institute at Stanford, and Departments of bChemical Engineering and cBioengineering, Stanford University, Stanford, Calif., USA
email Corresponding Author

Abstract

Aims: To determine the rate of diffusion of myoglobin and bovine serum albumin (BSA) through the human cornea. These small proteins have hydrodynamic diameters of approximately 4.4 and 7.2 nm, and molecular weights of 16.7 and 66 kDa, for myoglobin and BSA, respectively. Meth  ods: Diffusion coefficients were measured using a diffusion chamber where the protein of interest and balanced salt solution were in different chambers separated by an ex vivo human cornea. Protein concentrations in the balanced salt solution chamber were measured over time. Diffusion coefficients were calculated using equations derived from Fick’s law and conservation of mass in a closed system. Results: Our experiments demonstrate that the diffusion coefficient of myoglobin is 5.5 ± 0.9 × 10–8 cm2/s (n = 8; SD = 1.3 × 10–8 cm2/s; 95% CI: 4.6 × 10–8 to 6.4 × 10–8 cm2/s) and the diffusion coefficient of BSA is 3.1 ± 1.0 × 10–8 cm2/s (n = 8; SD = 1.4 × 10–8 cm2/s; 95% CI: 2.1 × 10–8 to 4.1 × 10–8 cm2/s). Conclusions: Our study suggests that molecules as large as 7.2 nm may be able to passively diffuse through the human cornea. With applications in pharmacotherapy and the development of an artificial cornea, further experiments are warranted to fully understand the limits of human corneal diffusion and its clinical relevance.


 goto top of outline Key Words

  • Cornea
  • Diffusion
  • Proteins
  • Human cornea
  • Myoglobin
  • Bovine serum albumin

 goto top of outline Abstract

Aims: To determine the rate of diffusion of myoglobin and bovine serum albumin (BSA) through the human cornea. These small proteins have hydrodynamic diameters of approximately 4.4 and 7.2 nm, and molecular weights of 16.7 and 66 kDa, for myoglobin and BSA, respectively. Meth  ods: Diffusion coefficients were measured using a diffusion chamber where the protein of interest and balanced salt solution were in different chambers separated by an ex vivo human cornea. Protein concentrations in the balanced salt solution chamber were measured over time. Diffusion coefficients were calculated using equations derived from Fick’s law and conservation of mass in a closed system. Results: Our experiments demonstrate that the diffusion coefficient of myoglobin is 5.5 ± 0.9 × 10–8 cm2/s (n = 8; SD = 1.3 × 10–8 cm2/s; 95% CI: 4.6 × 10–8 to 6.4 × 10–8 cm2/s) and the diffusion coefficient of BSA is 3.1 ± 1.0 × 10–8 cm2/s (n = 8; SD = 1.4 × 10–8 cm2/s; 95% CI: 2.1 × 10–8 to 4.1 × 10–8 cm2/s). Conclusions: Our study suggests that molecules as large as 7.2 nm may be able to passively diffuse through the human cornea. With applications in pharmacotherapy and the development of an artificial cornea, further experiments are warranted to fully understand the limits of human corneal diffusion and its clinical relevance.

Copyright © 2012 S. Karger AG, Basel


 goto top of outline References
  1. Chew HF, Ayres BD, Hammersmith BM, et al: Boston keratoprosthesis outcomes and complications. Cornea 2009;28:989–996.

    External Resources

  2. Kleinmann G, Larson S, Neuhann IM, et al: Intraocular concentrations of gatifloxacin and moxifloxacin in the anterior chamber via diffusion through the cornea using collagen shields. Cornea 2006;25:209–213.
  3. Allansmith M, de Ramus A, Maurice DM: The dynamics of IgG in the cornea. Invest Ophthalmol Vis Sci 1979;18:947–955.
  4. Ahmed I, Gokhale RD, Shah MV, Patton TF: Physicochemical determinants of drug diffusion across the conjunctiva, sclera, and cornea. J Pharm Sci 1987;76:583–586.
  5. Araie M, Maurice D: The rate of diffusion of fluorophores through the corneal epithelium and stroma. Exp Eye Res 1987;44:73–87.
  6. Robinson JR, Grass GM: Mechanisms of corneal drug penetration I: in vivo and in vitro kinetics. J Pharm Sci 1988;77:3–14.

    External Resources

  7. Myung D, Derr K, Huie P, Noolandi J, Ta KP, Ta CN: Glucose permeability of human, bovine, and porcine corneas in vitro. Ophthalmic Res 2006;38:158–163.
  8. Ottinger M, Thiel MA, Feige U, Lichtlen P, Urech DM: Efficient intraocular penetration of topical anti-TNF-alpha single-chain antibody (ESBA105) to anterior and posterior segment without penetration enhancer. Invest Ophthalmol Vis Sci 2009;50:779–786.

    External Resources

  9. Lee CJ, Vroom JA, Fishman HA, Bent SF: Determination of human lens capsule permeability and its feasibility as a replacement for Bruch’s membrane. Biomaterials 2006;27:1670–1678.
  10. Karring H, Thøgersen IB, Klintworth GK, Møller-Pedersen T, Enghild JJ: A dataset of human cornea proteins identified by peptide mass fingerprinting and tandem mass spectrometry. Mol Cell Proteomics 2005;4:1406–1408.

 goto top of outline Author Contacts

Christopher N. Ta
Byers Eye Institute at Stanford, Stanford University
2452 Watson Court, Room 2282
Palo Alto, CA 94303-5353 (USA)
Tel. +1 650 498 4791, E-Mail cta@stanford.edu


 goto top of outline Article Information

Received: November 11, 2010
Accepted after revision: May 27, 2011
Published online: March 2, 2012
Number of Print Pages : 6
Number of Figures : 4, Number of Tables : 3, Number of References : 10


 goto top of outline Publication Details

Ophthalmic Research (Journal for Research in Experimental and Clinical Ophthalmology)

Vol. 48, No. 1, Year 2012 (Cover Date: June 2012)

Journal Editor: Corcóstegui B. (Barcelona), Pelayes D. (Buenos Aires), Pleyer U. (Berlin)
ISSN: 0030-3747 (Print), eISSN: 1423-0259 (Online)

For additional information: http://www.karger.com/ORE


Copyright / Drug Dosage / Disclaimer

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

Abstract

Aims: To determine the rate of diffusion of myoglobin and bovine serum albumin (BSA) through the human cornea. These small proteins have hydrodynamic diameters of approximately 4.4 and 7.2 nm, and molecular weights of 16.7 and 66 kDa, for myoglobin and BSA, respectively. Meth  ods: Diffusion coefficients were measured using a diffusion chamber where the protein of interest and balanced salt solution were in different chambers separated by an ex vivo human cornea. Protein concentrations in the balanced salt solution chamber were measured over time. Diffusion coefficients were calculated using equations derived from Fick’s law and conservation of mass in a closed system. Results: Our experiments demonstrate that the diffusion coefficient of myoglobin is 5.5 ± 0.9 × 10–8 cm2/s (n = 8; SD = 1.3 × 10–8 cm2/s; 95% CI: 4.6 × 10–8 to 6.4 × 10–8 cm2/s) and the diffusion coefficient of BSA is 3.1 ± 1.0 × 10–8 cm2/s (n = 8; SD = 1.4 × 10–8 cm2/s; 95% CI: 2.1 × 10–8 to 4.1 × 10–8 cm2/s). Conclusions: Our study suggests that molecules as large as 7.2 nm may be able to passively diffuse through the human cornea. With applications in pharmacotherapy and the development of an artificial cornea, further experiments are warranted to fully understand the limits of human corneal diffusion and its clinical relevance.



 goto top of outline Author Contacts

Christopher N. Ta
Byers Eye Institute at Stanford, Stanford University
2452 Watson Court, Room 2282
Palo Alto, CA 94303-5353 (USA)
Tel. +1 650 498 4791, E-Mail cta@stanford.edu


 goto top of outline Article Information

Received: November 11, 2010
Accepted after revision: May 27, 2011
Published online: March 2, 2012
Number of Print Pages : 6
Number of Figures : 4, Number of Tables : 3, Number of References : 10


 goto top of outline Publication Details

Ophthalmic Research (Journal for Research in Experimental and Clinical Ophthalmology)

Vol. 48, No. 1, Year 2012 (Cover Date: June 2012)

Journal Editor: Corcóstegui B. (Barcelona), Pelayes D. (Buenos Aires), Pleyer U. (Berlin)
ISSN: 0030-3747 (Print), eISSN: 1423-0259 (Online)

For additional information: http://www.karger.com/ORE


Copyright / Drug Dosage

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

References

  1. Chew HF, Ayres BD, Hammersmith BM, et al: Boston keratoprosthesis outcomes and complications. Cornea 2009;28:989–996.

    External Resources

  2. Kleinmann G, Larson S, Neuhann IM, et al: Intraocular concentrations of gatifloxacin and moxifloxacin in the anterior chamber via diffusion through the cornea using collagen shields. Cornea 2006;25:209–213.
  3. Allansmith M, de Ramus A, Maurice DM: The dynamics of IgG in the cornea. Invest Ophthalmol Vis Sci 1979;18:947–955.
  4. Ahmed I, Gokhale RD, Shah MV, Patton TF: Physicochemical determinants of drug diffusion across the conjunctiva, sclera, and cornea. J Pharm Sci 1987;76:583–586.
  5. Araie M, Maurice D: The rate of diffusion of fluorophores through the corneal epithelium and stroma. Exp Eye Res 1987;44:73–87.
  6. Robinson JR, Grass GM: Mechanisms of corneal drug penetration I: in vivo and in vitro kinetics. J Pharm Sci 1988;77:3–14.

    External Resources

  7. Myung D, Derr K, Huie P, Noolandi J, Ta KP, Ta CN: Glucose permeability of human, bovine, and porcine corneas in vitro. Ophthalmic Res 2006;38:158–163.
  8. Ottinger M, Thiel MA, Feige U, Lichtlen P, Urech DM: Efficient intraocular penetration of topical anti-TNF-alpha single-chain antibody (ESBA105) to anterior and posterior segment without penetration enhancer. Invest Ophthalmol Vis Sci 2009;50:779–786.

    External Resources

  9. Lee CJ, Vroom JA, Fishman HA, Bent SF: Determination of human lens capsule permeability and its feasibility as a replacement for Bruch’s membrane. Biomaterials 2006;27:1670–1678.
  10. Karring H, Thøgersen IB, Klintworth GK, Møller-Pedersen T, Enghild JJ: A dataset of human cornea proteins identified by peptide mass fingerprinting and tandem mass spectrometry. Mol Cell Proteomics 2005;4:1406–1408.