What charge do microspheres carry?
We expect that most of our microspheres bear some charge, although we do not characterize them in this respect (e.g. via electrophoretic mobility, zeta potential, etc.). Charge will depend upon the specific surface groups that are present, the numbers in which they are present, and buffer composition and pH. We expect that non-functionalized polymer microspheres will bear a weak negative charge at neutral pH, due to negatively charged surface groups from the initiator. Microspheres that have been specifically functionalized will likely bear the greatest charge, e.g. from copolymerization of functional monomer, such as acrylic acid or methacrylic acid.
