June 2013
Volume 54, Issue 15
Free
ARVO Annual Meeting Abstract  |   June 2013
Correlation between release of rapamycin from Porous Silicon (pSi) and the color shifting of pSi monitored by a digital camera: a prototype of non-invasive remote monitoring system for intravitreal drug release
Author Affiliations & Notes
  • Lingyun Cheng
    Jacobs Retina Ctr at Shiley Eye Ctr, Univ of California-San Diego, La Jolla, CA
  • Huiyuan Hou
    Jacobs Retina Ctr at Shiley Eye Ctr, Univ of California-San Diego, La Jolla, CA
  • Alejandra Nieto
    Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA
  • Gordon Miskelly
    School of Chemical Sciences, University of Auckland, New Zealand, Auckland, New Zealand
  • Dirk-Uwe Bartsch
    Jacobs Retina Ctr at Shiley Eye Ctr, Univ of California-San Diego, La Jolla, CA
  • William Freeman
    Jacobs Retina Ctr at Shiley Eye Ctr, Univ of California-San Diego, La Jolla, CA
  • Michael Sailor
    Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA
  • Footnotes
    Commercial Relationships Lingyun Cheng, Spinnaker Biosciences (C); Huiyuan Hou, None; Alejandra Nieto, None; Gordon Miskelly, None; Dirk-Uwe Bartsch, None; William Freeman, OD-OS, Inc. (C); Michael Sailor, Spinnaker Biosciences (I)
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2013, Vol.54, 1084. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to Subscribers Only
      Sign In or Create an Account ×
    • Get Citation

      Lingyun Cheng, Huiyuan Hou, Alejandra Nieto, Gordon Miskelly, Dirk-Uwe Bartsch, William Freeman, Michael Sailor; Correlation between release of rapamycin from Porous Silicon (pSi) and the color shifting of pSi monitored by a digital camera: a prototype of non-invasive remote monitoring system for intravitreal drug release. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1084.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract
 
Purpose
 

pSi photonic crystals can be created through etching with a periodically varying current to impart a color to these particles. Drug loading and release can be measured by reflectance spectroscopy. The current study aims to investigate the feasibility of monitoring drug release from pSi photonic crystals by in vitro digital imaging of the color changes associated with pSi degradation and drug release.

 
Methods
 

pSi was prepared by electrochemical etch of a silicon wafer. pSi microparticles were prepared by ultrasonic fracture. The pSi surface was chemically modified with undecylenic acid and then partially oxidized before rapamycin loading through infiltration (pore size ~15 nm). Rapamycin-loaded pSi particles were added to 4.5mL of HBSS in a petri dish which was incubated at 37°C. At predetermined time points, the pSi particles in the dish were photographed using a digital camera with coaxial lighting and the dissolution medium was sampled for rapamycin quantitation. The photographs were imported into Image J and the color of the particles was measured after thresholding of the images.

 
Results
 

Hydrolytic and oxidative degradation of pSi, and release of rapamycin from pSi caused an observable change of the pSi particles from reddish to yellowish and then to transparent. The corresponding changes in the reflected light intensity was correlated with the cumulative drug release (r=0.93, p<0.0001; Figure). These optical effects result from a blue-shift in the spectral peaks displayed by the photonic crystals during the pSi degradation/drug release process. At the early stage the reflected light intensity increased mainly due to the drug release while the light intensity decline at later stage mainly from degradation of pSi.

 
Conclusions
 

Rapamycin release from pSi photonic crystals can be quantitatively monitored with a digital camera which will allow a non-invasive and remote monitoring for an intravitreally injected drug and pSi delivery system.

  
Keywords: 551 imaging/image analysis: non-clinical • 608 nanomedicine • 688 retina  
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×