The following are examples of our biomaterials projects
that have been published. We are currently pursuing these and other areas
of related research. We consider our drug
delivery research to be biomaterials research.
Osteoblast-like cell attachment to and calcification of novel phosphonate-containing polymeric substrates Gemeinhart, Bare, Haasch, and Gemeinhart
[back to top]
Abstract: In an attempt to interact natural bone and bone cells with biomaterials and to begin to develop modular tissue engineering scaffolds, substrates containing phosphonate groups were identified to mimic mineral-protein and natural polymer-protein interactions. In this study, we investigated poly(vinyl phosphonic acid) copolymer integration with existing materials as a graft-copolymer surface modification. Phosphonate-containing copolymer-modified surfaces were created and shown to have varying phosphate content within different polymeric surfaces. As the phosphonate content in the monomer feed approached 30% vinyl phosphonic acid, increased osteoblast-like cell adhesion (3-8 fold increase in adhesion) and proliferation (2-10 fold increase in proliferation rate) was observed. Since surfaces modified with 30% vinyl phosphonic acid in the feed exhibited a maximal cell adhesion and proliferation (9.4x104 cells/cm2/day), it was hypothesized that this copolymer composition was optimal for protein-polymer interactions. Osteoblast-like cells formed confluent layers and were able to differentiate on all surfaces that contained vinyl phosphonic acid. Most importantly, cells interacting with these surfaces were able to significantly mineralize the surface. These results suggest that phosphonate-containing polymers can be used to integrate biomaterials with natural bone and could be used for tissue engineering applications.
Cellular
Alignment by Grafted Adhesion Peptide Surface Density Gradients
Kang, Gemeinhart, and Gemeinhart
Abstract: The extracellular matrix and extracellular
matrix-associated proteins play a major role in growth and differentiation
of tissues and organs. To date, few methods have been developed that
allow researchers to examine the affect of surface density gradients
of adhesion molecules in a controlled manner. Fibroblasts cultured
on surfaces with a surface density gradient of RGD peptide aligned
parallel to the gradient while fibroblasts on constant density RGD
surfaces spread but did not align as has been shown in numerous earlier
studies. Not only did fibroblasts align on the gradient surfaces,
but they also showed significantly greater elongation than on constant
density peptide surfaces or on control surfaces. This type of method
is easy to replicate and can be used by laboratories interested in
investigating alignment of various cell types without mechanical force
or other stimulation, and without cell-cell interaction or for investigation
of affects of surface density gradients of molecules on cellular biochemistry
and biophysics. This method also has potential applications for developing
scaffolds for tissue engineering applications where cellular alignment
is necessary.
Improved
cell adhesion and proliferation on synthetic phosphonic acid-containing
hydrogels
Tan, Gemeinhart, Ma, and Gemeinhart [back to top]
Abstract: Hydrogels with tissue-like mechanical properties
are highly attractive scaffolds for tissue engineering. In this study,
copolymers containing vinyl phosphonic acid (VPA) and acrylamide (AM)
were tested for their swelling, protein uptake in serum supplemented
medium, and cell adhesion and proliferation. The swelling of the gels
in serum containing culture medium increased with increasing VPA content.
The presence of VPA also increased protein uptake of gels in medium;
gels polymerized with more than 50% of VPA absorbed as much as 100
g/cm2 of protein, twice the amount absorbed by gels made with only
acrylamide. The adhesion and growth of three types of cells, NIH 3T3
fibroblast, osteoblast-like MG-63 and Saos-2, were significantly improved
on the gels made with 50% or more VPA; the number of adherent Mg-63
cells increased 3 fold while the growth rate increased 4 fold. Similar
results were obtained for Saos-2 and 3T3 cells. The adhesion and growth
of the three cell types on gels with sufficient phosphonate content
were at least comparable to, or even better than, that on commercially
available tissue culture plates. These results suggest great potential
of anionic gels in bone tissue engineering.
DISCLAIMER: The opinions and links of this page and all pages maintained by Rick Gemeinhart are in no way representative of The University of Illinois, the Departments of Biopharmaceutical Sciences, Bioengineering, or Ophthalmology and Visual Sciences, the Colleges of Engineering, Medicine or Pharmacy or anyone other than the Rick Gemeinhart. These pages are for the dissemination of information from the Gemeinhart Research Group, and should not be reproduced for any purpose other than for personal or educational use.
Inspired by many websites online, but in particular those implemented by Tonglei Li (http://xtal.gws.uky.edu/).
Manuscript