Navigation Links
Silk-based surgical implants could offer a better way to repair broken bones

MEDFORD/SOMERVILLE, MASS. AND BOSTON -- When a person suffers a broken bone, treatment calls for the surgeon to insert screws and plates to help bond the broken sections and enable the fracture to heal. These "fixation devices" are usually made of metal alloys.

But metal devices may have disadvantages: Because they are stiff and unyielding, they can cause stress to underlying bone. They also pose an increased risk of infection and poor wound healing. In some cases, the metal implants must be removed following fracture healing, necessitating a second surgery. Resorbable fixation devices, made of synthetic polymers, avoid some of these problems but may pose a risk of inflammatory reactions and are difficult to implant.

Now, using pure silk protein derived from silkworm cocoons, a team of investigators from Tufts University School of Engineering and Beth Israel Deaconess Medical Center (BIDMC) has developed surgical plates and screws that may not only offer improved bone remodeling following injury, but importantly, can also be absorbed by the body over time, eliminating the need for surgical removal of the devices.

The findings, demonstrated in vitro and in a rodent model, are described in the March 4 issue of Nature Communications.

"Unlike metal, the composition of silk protein may be similar to bone composition," says co-senior author Samuel Lin, MD, of the Division of Plastic and Reconstructive Surgery at BIDMC and Associate Professor of Surgery at Harvard Medical School. "Silk materials are extremely robust. They maintain structural stability under very high temperatures and withstand other extreme conditions, and they can be readily sterilized."

Collaborating with Lin were co-senior author and Tufts chair of biomedical engineering David Kaplan, PhD, a leader in the use of silk for biomedical applications, and a team of biomedical and mechanical engineers.

"One of the other big advantages of silk is that it can stabilize and deliver bioactive components, so that plates and screws made of silk could actually deliver antibiotics to prevent infection, pharmaceuticals to enhance bone regrowth and other therapeutics to support healing," says Kaplan.

Kaplan and his team have previously developed silk-based sponges, fibers and foams for use in the operating room and in clinical settings. But until now, silk hadn't been used in the development of a solid medical device for fracture fixation.

The Tufts researchers used silk protein obtained from Bombyx mori (B. mori) silkworm cocoons to form the surgical plates and screws. Produced from the glands of the silkworm, the silk protein is folded in complex ways that give it unique properties of both exceptional strength and versatility.

To test the new devices, the investigators implanted a total of 28 silk-based screws in six laboratory rats. Insertion of screws was straightforward and assessments were then conducted at four weeks and eight weeks, post-implantation.

"No screws failed during implantation," says Kaplan, explaining that because silk is slow to swell, the new devices maintained their mechanical integrity even when coming into contact with fluids and surrounding tissue during surgery. The outcomes suggest that the use of silk plates and screws can spare patients the complications that can develop when metal or synthetic polymer devices come into contact with fluids.

"Having a resorbable, long-lasting plate and screw system has potentially huge applications," says Lin. While the initial aim is to use silk-based screws to treat facial injuries, which occur at a rate of several hundred thousand each year, the devices have the potential for the treatment of a variety of different types of bone fractures.

"Because the silk screws are inherently radiolucent [not seen on X-ray] it may be easier for the surgeon to see how the fracture is progressing during the post-op period, without the impediment of metal devices," adds Lin. "And having an effective system in which screws and plates 'melt away' once the fracture is healed may be of enormous benefit. We're extremely excited to continue this work in larger animal models and ultimately in human clinical trials."

Contact: Bonnie Prescott
Beth Israel Deaconess Medical Center

Related biology news :

1. National Robotics Initiative grant to create smarter surgical robots
2. Non-Surgical Procedures are Now Available at a Discount at Strax Rejuvenation
3. Nonsurgical treatment turns back the clock, shrinks enlarged prostate
4. Medical societies unite on patient-centered measures for nonsurgical stroke interventions
5. Surgical Theater, LLC sells first Surgical Rehearsal Platform to UH Case Medical Center
6. Pre-surgical steps for eye surgery are standardized through JoVEs video publication
7. Researchers discover non-surgical test for brain cancer
8. Global Surgical Devices Market Growth Driven by Improving Standards of Living and Longer Life Expectancies, Research Shows
9. Cochlear implants -- with no exterior hardware
10. Study finds natural compound can be used for 3-D printing of medical implants
11. New research association started: Magnesium implants shall facilitate bone fracture healing
Post Your Comments:
(Date:10/29/2015)... , Oct. 29, 2015  Rubicon Genomics, Inc., ... U.S. distribution of its DNA library preparation products, ... Rubicon,s new ThruPLEX Plasma-seq kit. ThruPLEX Plasma-seq has ... preparation of NGS libraries for liquid biopsies--the analysis ... and prognostic applications in cancer and other conditions. ...
(Date:10/29/2015)... NXTD ) ("NXT-ID" or ... the growing mobile commerce market and creator of ... leading marketplace to discover and buy innovative technology ... on StackSocial for this holiday season.   ... a biometric authentication company focused on the growing ...
(Date:10/27/2015)... NEW YORK , Oct. 27, 2015 ... the major issues of concern for various industry verticals ... This is due to the growing demand for secure ... practices in various ,sectors, such as hacking of bank ... concerns for electronic equipment such as PC,s, laptops, and ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... , November 26, 2015 ... Biobanking Market 2016 - 2020 report analyzes that ... integrity and quality in long-term samples, minimizing manual ... cost-effectiveness. Automation minimizes manual errors such as mislabeling ... efficiency. Further, it plays a vital role in ...
(Date:11/25/2015)... ANGELES and HOLLISTON, Mass. ... Technology, Inc. (Nasdaq: HART ), a biotechnology company ... that CEO Jim McGorry will present at ... December 1, 2015 at 2:30 p.m. PT. The presentation ... below) for 30 days. Management will also be available ...
(Date:11/25/2015)... DIEGO , Nov. 25, 2015 Orexigen® ... management will participate in a fireside chat discussion at ... New York . The discussion is scheduled ... .  A replay will be ... Media Contact:McDavid Stilwell  , Julie NormartVP, Corporate Communications ...
(Date:11/24/2015)... , ... November 24, 2015 , ... The United States ... of the 2016 USGA Green Section Award. Presented annually since 1961, the USGA Green ... or her work with turfgrass. , Clarke, of Iselin, N.J., is an ...
Breaking Biology Technology: