Nanotech 2009 Vol. 1
Nanotech 2009 Vol. 1
Nanotechnology 2009: Fabrication, Particles, Characterization, MEMS, Electronics and Photonics

Nanoscale Characterization Chapter 4

Environmental Digital Pulsed Force Mode AFM in Biomedical Coatings Research

Authors: G. Haugstad, K. Wormuth

Affilation: University of Minnesota, United States

Pages: 277 - 280

Keywords: AFM, drug elution, Raman spectroscopy, polymer, coating

We report ongoing methodological developments using Digital Pulsed Force Mode AFM of model coatings containing the drug dexamethasone dispersed in polylactide (biodegradable), poly(butylmethacrylate) (PBMA), and PBMA/poly(laurel methacrylate) (PLMA) blends. Studies include (1) multi-technique analyses, understanding D-PFM AFM results in conjunction with electron, light and confocal-Raman microscopy; (2) comparing drug-polymer segregation in microsprayed and spin-cast coatings, to examine kinetic differences in coating application (i.e., of solvent evaporation); (3) aqueous AFM of drug elution, in conjunction with conventional drug-release profiles; and (4) elevated temperature and humidity as “knobs” to yield material contrast and mobilize drug. Corresponding results include (1) the identification of SEM e-beam modifications, and distinctly different surface vs. bulk (AFM vs. Raman) drug segregation, important to burst vs. longer term release; (2) dramatic differences in drug segregation in sprayed vs. spin-cast coatings; (3) rapid formation of nanoscale surface holes during burst phase, and subsurface drug aggregation then release over much longer times; (4) both humidity- and temperature-induced drug crystallization in the vicinity of rubbery polymer domains in which the drug is less miscible. We conclude that environmental D-PFM AFM is an extraordinarily powerful tool to assess myriad issues within drug-eluting coatings research and development.

ISBN: 978-1-4398-1782-7
Pages: 702
Hardcopy: $179.95

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