Navigation Links
Nanotextured implant materials: blending in, not fighting back

Biomedical engineers are constantly coming up with ways to repair the human body, replacing defective and worn out parts with plastic, titanium, and ceramic substitutes ?but the body does not always accept such substitutes seamlessly. Engineers from Brown and Purdue universities have found that simply changing the surface texture of implants can dramatically change the way cells colonize a wide variety of materials.

Two recent experiments have focused on the materials used in stents ?those springy little cylinders that hold open once-clogged arteries ?and artificial blood vessels. Currently only about 30 percent of small diameter blood vessel grafts (less than 6 mm diameter) last more than five years, and up to 20 percent of stents need to be replaced because the artery walls thicken in and around them in a process known as restenosis. Drug-coated stents were introduced years ago as one way to combat this problem, but concerns have surfaced recently about increased clotting.

Instead of using chemistry to fight the body's response to such foreign materials, Thomas Webster, an associate professor of engineering, and Karen Haberstroh, an assistant professor of engineering, thought maybe they could use physical structure to allow the foreign materials to blend in better. "What we're trying to do is fundamentally different," says Webster. "We're trying to find materials that the body accepts, rather than develop drugs or develop materials that will kill a cell ?no matter if it kills a bad cell or a good cell. We're trying to find materials that accept good cells, as opposed to killing off bad cells."

Normal healthy blood vessels have a thin lining of specialized cells called the endothelium, surrounded by a thicker layer of smooth muscle cells that make up the arterial wall. The proteins collagen and elastin make up much of this lining and create a texture of fine nanoscale bumps on the inside of the blood vessel. This contrasts strongly with most of the materials used in implants, which have microscale texture, but are nearly smooth at the nanoscale.

When the researchers changed the surface texture of implant materials to better match the natural texture of the endothelium, they found that endothelial cells quickly colonized the foreign surfaces, effectively camouflaging them and preventing smooth muscle cells from overgrowing the implants. Once the endothelial cells form a single, solid layer, they stop piling on and switch to producing the proteins collagen and elastin.

In one experiment, published with Purdue University graduate student Saba Choudhary in the journal Tissue Engineering, Webster and Haberstroh pressed together titanium particles that were less than 1 micron in size to create titanium with nanoscale surface texture. When they compared samples of the nanostructured material to conventional titanium in mixed cell culture, they found that the nanoscale surface features encouraged endothelial cells to colonize the material and spread much faster than smooth muscle cells. Where endothelial cells established themselves, they formed a single thin layer that inhibited overgrowth of the smooth muscle cells that tends to narrow stented arteries.

In another experiment, published in the Journal of Biomedical Materials Research with Purdue graduate student Derick Miller, the team molded pieces of PLGA, a biodegradable polymer often used for blood vessel grafts, so they came out completely covered with bumps that were 100, 200 or 500 nanometers in diameter. The surface with 200-nanometer features strongly favored the adsorption and spreading of fibronectin, a protein that helps endothelial cells quickly coat the graft.

Webster and Haberstroh's next step will be to test s uch nanostructured implants in live animals. If the same behavior holds true for materials placed in the body, the rapid growth of endothelial cells would help the implants to integrate quickly into existing blood vessels, provoking less immune response and a longer-lasting repair.


'"/>

Source:Brown University


Related biology news :

1. Ophthalmologists implant five patients with artificial silicon retina microchip
2. Polymers with copper show promise for implanted sensors
3. Engineers improve plastics potential for use in implants by linking it to biological material
4. Innovative coating could give medical implants a longer life
5. Magnetic probe successfully tracks implanted cells in cancer patients
6. Sooner is better with cochlear implants, Stanford scientist shows
7. Breast implants not associated with cancer risk, study reports
8. New implanted contacts designed to fix nearsightedness
9. With cochlear implants, earlier use leads to better speech
10. Protein-coated dental implants could improve bone regeneration
11. Nanotechnology being used to improve biocompatibility of human prosthetics and implants
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:12/8/2016)... -- Singulex, Inc., the leader in Next Generation Immunodiagnostics powered ... and supply agreement with Thermo Fisher Scientific, the world ... to Thermo Scientific BRAHMS PCT (Procalcitonin), a biomarker which, ... diagnose systemic bacterial infection and sepsis and in ... assessing the risk of critically ill patients for progression ...
(Date:12/7/2016)... , Dec. 7, 2016   Veridium ... announced the appointment of new CEO James ... executive with decades of experience, has served in ... Cisco, where he specialized in expanding a pipeline ... technology portfolios. He most recently served as managing ...
(Date:12/5/2016)... 5, 2016  The Office of Justice Programs, ... CT Scans Enhance or Replace Medico Legal Autopsies?" ... supporting or replacing forensic autopsies with postmortem X-ray ... In response to recommendations made by The ... CT scans as a potential component of medicolegal ...
Breaking Biology News(10 mins):
(Date:12/8/2016)... , Dec. 8, 2016 This report analyzes the ... Segments: Acid Based (Humic, Amino, & Fulvic), Extract Based, and ... following Crop Types: Ornamental & Turf, Row Crops, and Others. ... Canada , Japan , ... Latin America , and Rest of World. Annual ...
(Date:12/8/2016)... ... December 08, 2016 , ... From wearable devices ... taking over sports. On Thursday, December 15th a panel of entrepreneurs, innovators and ... playing field at a Smart Talk session. Smart Talk will run from 8:30 ...
(Date:12/8/2016)... 8, 2016  Renova™ Therapeutics, a biotechnology company ... and type 2 diabetes, announced that it has ... virus (AAV) vector developed in the laboratory of ... Stanford University. The company plans to use this ... product pipeline. "Early research has ...
(Date:12/8/2016)... ... December 08, 2016 , ... ... that provide essential device-to-computer interconnect using USB or PCI Express, announced the FOMD-ACV-A4, ... The FOMD-ACV-A4 is a small, thin, SODIMM-style module that fits a standard 204-pin ...
Breaking Biology Technology: