title: A novel flexible microfluidic meshwork to reduce fibrosis in glaucoma surgery.
abstract: Fibrosis and hence capsule formation around the glaucoma implants are the main reasons for glaucoma implant failure. To address these issues, we designed a microfluidic meshwork and tested its biocompatibility in a rabbit eye model. The amount of fibrosis elicited by the microfluidic meshwork was compared to the amount elicited by the plate of conventional glaucoma drainage device.
  
  
  METHODS
  Six eyes from 3 New Zealand albino rabbits were randomized to receive either the novel microfluidic meshwork or a plate of Ahmed glaucoma valve model PF7 (AGV PF7). The flexible microfluidic implant was made from negative photoresist SU-8 by using micro-fabrication techniques. The overall size of the meshwork was 7 mm × 7 mm with a grid period of 100 μm. Both implants were placed in the subtenon space at the supratemporal quadrant in a standard fashion. There was no communication between the implants and the anterior chamber via a tube. All animal eyes were examined for signs of infection and implant erosion on days 1, 3, 7, and 14 and then monthly. Exenterations were performed in which the entire orbital contents were removed at 3 months. Histology slides of the implant and the surrounding tissues were prepared and stained with hematoxylin-eosin. Thickness of the fibrous capsules beneath the implants were measured and compared with paired student's t-test between the two groups.
  
  
  RESULTS
  The gross histological sections showed that nearly no capsule formed around the microfluidic meshwork in contrast to the thick capsule formed around the plate of AGV PF7. Thickness of the fibrotic capsules beneath the AGV PF7 plate from the 3 rabbit eyes was 90μm, 82μm, and 95 μm, respectively. The thickness at the bottom of fibrotic capsules around the new microfluidic implant were 1μm, 2μm, and 1μm, respectively. The difference in thickness of capsule between the two groups was significant (P = 0.002). No complications were noticed in the 6 eyes, and both implants were tolerated well by all rabbits.
  
  
  CONCLUSIONS
  The microfluidic meshwork elicited minimal fibrosis and capsule formation after 3-months implantation in a rabbit model. This provides promising evidence to aid in future development of a new glaucoma drainage implant that will elicit minimal scar formation and provide better long-term surgical outcomes.
authors.affiliation: Department of Ophthalmology, University of California, San Francisco, California, United States of America.
authors.forename: Behzad
authors.initials: B
authors.lastname: Amoozgar
authors.affiliation: Department of Biomedical Engineering, the University of Texas at Austin, Austin, Texas, United States of America.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Ophthalmology, University of California, San Francisco, California, United States of America.
authors.forename: Jun
authors.initials: J
authors.lastname: Hui Lee
authors.affiliation: Department of Ophthalmology, University of California, San Francisco, California, United States of America.
authors.forename: Michele
authors.initials: M
authors.lastname: Bloomer
authors.affiliation: Department of Biomedical Engineering, the University of Texas at Austin, Austin, Texas, United States of America.
authors.forename: Zhengtuo
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Ophthalmology, University of California, San Francisco, California, United States of America.
authors.forename: Paul
authors.initials: P
authors.lastname: Coh
authors.affiliation: Department of Biomedical Engineering, the University of Texas at Austin, Austin, Texas, United States of America.
authors.forename: Fei
authors.initials: F
authors.lastname: He
authors.affiliation: Department of Physics, the University of Texas at Austin, Austin, Texas, United States of America.
authors.forename: Lan
authors.initials: L
authors.lastname: Luan
authors.affiliation: Department of Biomedical Engineering, the University of Texas at Austin, Austin, Texas, United States of America.
authors.forename: Chong
authors.initials: C
authors.lastname: Xie
authors.affiliation: Department of Ophthalmology, University of California, San Francisco, California, United States of America.
authors.forename: Ying
authors.identifier: http://orcid.org/0000-0001-8131-7971
authors.initials: Y
authors.lastname: Han
mesh_terms: D000818:Animals; D005355:Fibrosis / Q000517:prevention & control*; D005901:Glaucoma / Q000473:pathology / Q000601:surgery*; D044085:Microfluidics; D019919:Prosthesis Implantation; D011817:Rabbits