Article

Biomedical Microdevices

, 11:959

First online:

A passive MEMS drug delivery pump for treatment of ocular diseases

  • Ronalee LoAffiliated withDepartment of Biomedical Engineering, Viterbi School of Engineering, University of Southern California
  • , Po-Ying LiAffiliated withDepartment of Electrical Engineering, Viterbi School of Engineering, University of Southern California
  • , Saloomeh SaatiAffiliated withDepartment of Ophthalmology, Keck School of Medicine, University of Southern California
  • , Rajat N. AgrawalAffiliated withDepartment of Ophthalmology, Keck School of Medicine, University of Southern California
  • , Mark S. HumayunAffiliated withDepartment of Ophthalmology, Keck School of Medicine, University of Southern California
  • , Ellis MengAffiliated withDepartment of Biomedical Engineering, Viterbi School of Engineering, University of Southern CaliforniaDepartment of Electrical Engineering, Viterbi School of Engineering, University of Southern California Email author 

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Abstract

An implantable manually-actuated drug delivery device, consisting of a refillable drug reservoir, flexible cannula, check valve, and suture tabs, was investigated as a new approach for delivering pharmaceuticals to treat chronic ocular diseases. Devices are fabricated by molding and bonding three structured layers of polydimethylsiloxane. A 30 gauge non-coring needle was used to refill the reservoir; this size maximized the number of repeated refills while minimizing damage to the reservoir. The check valve cracking pressure was 76 ± 8.5 mmHg (mean ± SE, n = 4); the valve sustained > 2000 mmHg of reverse pressure without leakage. Constant delivery at 1.57 ± 0.2 µL/sec and 0.61 ± 0.2 µL/sec (mean ± SE, n = 4) under 500 mmHg and 250 mmHg of applied pressure, respectively, was obtained in benchtop experiments. The valve closing time constant was 10.2 s for 500 mmHg and 14.2 s for 250 mmHg. Assembled devices were successfully demonstrated in benchtop, ex vivo, and in vivo experiments.

Keywords

Manual actuation Drug pump Polydimethylsiloxane Ocular diseases