De. Chickering et E. Mathiowitz, BIOADHESIVE MICROSPHERES .1. A NOVEL ELECTROBALANCE-BASED METHOD TO STUDY ADHESIVE INTERACTIONS BETWEEN INDIVIDUAL MICROSPHERES AND INTESTINAL-MUCOSA, Journal of controlled release, 34(3), 1995, pp. 251-262
A simple electrobalance-based method has been developed to measure bio
adhesive interactions between individual polymer microspheres and biol
ogical tissues. Environmental conditions, such as temperature and pH,
are easily controlled to mimic physiological parameters. The technique
is unique in that it allows the measurement of many parameters: compr
essive deformation, peak compressive load, yield point, peak tensile l
oad, deformation to peak load, fracture strength, deformation to failu
re, compressive work, returned work, and tensile work in a single expe
riment. The method has been shown to be statistically reproducible and
accurate. Using this technique, several hydrophobic, thermoplastic po
lymers and one hydrogel were studied. Go-polymers of fumaric and sebac
ic acid, of the polyanhydride family, produced bioadhesive fracture st
rengths greater than 50 mN/cm(2) with rat small intestinal mucosa, in
vitro. We suggest that bioadhesion in these hard, bioerodible material
s is not due to chain entanglement, as required by the diffusion theor
y of bioadhesion, but due to numerous hydrogen bonds generated between
hydrophilic functional groups (-COOH) and mucus glycoproteins.