April 3, 2006
Nanostructured Materials Support Cell Growth
Using materials engineered to have a defined nanoscale surface structure, two different research groups have developed materials that could be used to grow cancer cells in a way that more closely mimics their native environment in the body. In addition to the help that these materials could give to researchers attempting to better understand the basic biology of cancer cells, this new work could lead to cell-based assay systems for detecting cancer.
Reporting its work in the journal Biomaterials, a team of investigators led by Paolo Milani, Ph.D., at the University of Milan, in Italy, showed that nanostructured films of titanium dioxide, prepared using a supersonic beam of titanium oxide nanoparticles, has the granularity and porosity that is remarkably similar to that of the extracellular matrix upon which all cells grow in the body. Typically, most materials need to be coated with a mixture of DNA and proteins to create the optimal surface to support cell growth.
The researchers then used the titanium film as a substrate for growing various cancer cells. From these studies, the investigators concluded that cancer cells, as well as various normal cells, display normal growth and metabolism for periods lasting at least 20 days. And even though these films support normal cell growth without the need for coating them with proteins or DNA, the chemical properties of the films would allow researchers to attach a wide variety of molecules. As a result, researchers could attach "reporter" molecules to the film that would then signal when the cells exhibit certain behaviors, such as in response to chemotherapy.
Taking a completely different approach, Rein Ulijn, Ph.D., and his colleagues at the University of Manchester, in the United Kingdom, have used a set of peptides to create a three-dimensional gel that mimics the extracellular matrix in supporting cell growth. Reporting its work in the journal Advanced Materials, this team synthesized a library of seven peptides that self-assemble into a stable nanostructured hydrogel when mixed with water at physiological pH.
Three of the subsequent gels were stable enough that the researchers explored whether these gels would support normal cell growth. First, the investigators showed that cells would grow on a thin film of the gel containing growth medium. With that test a success, the researchers then mixed cells with the peptides, allowing the nanostructured gel to form around the cells in much the same way that the extracellular matrix surrounds cells growing in the body. Microscopic examination of the resulting cell-gel mix showed that the cells were growing and proliferating in the nanostructured environment of the hydrogel.
The work with titanium dioxide films is detailed in a paper titled, "Biocompatibility of cluster-assembled nanostructured TiO2 with primary and cancer cells." An investigator from the European Institute of Oncology, in Milan, also participated in this study. An abstract of this paper is available through PubMed.
The work with peptide hydrogels is detailed in a paper titled, "Nanostructured hydrogels for three-dimensional cell culture through self-assembly of fluorenylmethoxycarbonyl-dipeptides." An abstract of this paper is available at the journal's website.