Scientists at the Medical University of South Carolina are using inkjet printers to lay down cells and gels to make 3 dimensional cell structures.
Three-dimensional tubes of living tissue have been printed using modified desktop printers filled with suspensions of cells instead of ink. The work is a first step towards printing complex tissues or even entire organs."This could have the same kind of impact that Gutenberg's press did," claims tissue engineer Vladimir Mironov of the Medical University of South Carolina.
One enabling technology for this work came from Thomas Boland of Clemson University who developed the idea of printing biomaterials on surfaces.
1. Protein Printing
The research involves deposition of proteins in patterns or arrays using the protein printer, a device developed in the laboratory. Protein printing allows high throughput, fully automated deposition of a variety of biomolecules such as DNA , proteins, antibodies or drugs onto polymeric supports such as petri-dishes or tissue engineering scaffolds. Currently, the device is used to analyze 300,000 potential anti cancer drugs for their ability to prevent angiogenesis.
2. Cell Printing
Cell printing is the extension of protein printing to entire cells. The cell printer developed in the laboratory is fully automated and allows to deposit live cells with 500 nm precision on to supports such as tissue engineering scaffolds. Current research includes the deposition of enothelial cells for in vitro tube formation, single cell microculture and single cancer cell characterization.
An important enabling technology for this work is the thermoreversible gel which is also delivered by a printer cartridge over each cell layer to provide a structure to allow build-up of a 3 dimensional structure.
Called a stimuli-sensitive polymer, the material is designed to change immediately from a liquid into a gel in response to stimulus, such as an increase in temperature. This feature would enable physicians to inject the mixture of the polymer and a medicinal solution directly into a specific target in the body, where it would warm and instantly gel.
"Stimuli-sensitive gels show promise for the effective treatment of inoperable tumors," said Anna Gutowska, senior research scientist at PNNL and lead developer of the gel. "While much more research remains to be done before this becomes an accepted medical procedure, we are very excited about its potential."
Gutowska has spent many years developing biocompatible gels for drug delivery, cartilage repair and other medical applications. This latest work appears to be an outgrowth of her previous collaboration with MUSC researchers to use a gel as a scaffolding for the growth of cartilage.
In related research, PNNL is collaborating with the Medical University of South Carolina to test a biodegradable version of the polymer gel to support repair of articular cartilage—the durable type of cartilage that provides cushion between knee joints and other joints in the body.
Once injured, articular cartilage doesn't heal well, or typically at all on its own. Consequently, more than one million cartilage repair surgeries are conducted annually. However, there are limitations to the effectiveness of these surgeries because physicians have been unable to spur growth of articular cartilage inside the body.
To try to encourage growth and healing, cartilage cells, called chondrocytes, are extracted from a different site within the body for cultivation in the laboratory. Not only does this create another defect at the removal site, but physicians have been unable to cultivate chondrocytes with all the properties required to generate articular cartilage. Rather, a weaker, less durable type called fibrocartilage forms.
Through a two-year, DOE-funded project, Gutowska and collaborators at the Medical University of South Carolina are developing two components to support the successful repair of articular cartilage. The first is a three-dimensional cell culture system to support the in-laboratory growth of chondrocytes that retain the properties necessary for articular cartilage repair. A patent recently was issued for this technology.
The second component is a biodegradable polymer gel that can be injected into the defect to serve as a temporary synthetic "scaffold" to support growth of the injected chondrocytes. Testing of the biodegradable gel currently is taking place at the Medical University of South Carolina.
The idea of using common inkjet printers for laying down biomaterials and even living cells demonstrates how advances in other technological fields provide mature technologies for use in bioengineering. Also, the development of the thermosensitive biocompatible gel demonstrates that bioengineering involves a lot more than just the understanding and manipulation of cells.
|Share |||Randall Parker, 2003 January 22 07:59 PM Biotech Manipulations|