Interest in silk has been growing within the biomedical engineering community in recent years, thanks to the remarkable properties of silk proteins and fibers. Silk is strong and durable, can be engineered to be non-immunogenic, and is completely resorbable. We have covered several novel applications of silk in medicine previously, including neural electrode interfaces, nerve repair, bioelectronics, and tissue scaffoling.
Most recently, silk has been incorporated into biosensors. Peter Domachuk, a physicist at the University of Sydney, conceived of using silk as a biosensor component while working with Fiorenzo Omenetto and David Kaplan at Tufts University in Boston. In principle, various biochemically reactive proteins may be embedded in silk fibers, which may then be assembled into “bio-chips”. As a proof-of-concept, Dr. Domachuk and his team have successfully created an oxygen sensor by embedding hemoglobin proteins within silk fibers. In the future, the group hopes to embed a broad range of proteins within a single chip, enabling the simultaneous testing of several parameters at the bedside.
More from the University of Sydney press release:
The protein that underpins the strength of silk, fibroin, can be purified to form a clear material that can be used to display tiny drops of thousands of different biochemical compounds in patterns where they are no farther apart than the width of a human hair. These test compounds can then be simultaneously exposed to and react with body fluids such as human blood.
“The particularly interesting thing about silk,” Peter says, “is that the biochemical compounds it holds retain their activity. This biochemical activity enables extra sensitivity for monitoring and detecting medical conditions. And fibroin is transparent and can be formed into structures to control light which can be then used as a sensitive probe for improved medical testing. What’s more, silk doesn’t trigger the human immune response when it comes into contact with tissue.”
The above combination of factors makes silk a unique candidate for implantable biochips – devices like electronic microchips that can sit in or under the skin and detect chemicals in the blood. This can allow quick and accurate determination of medical conditions without the need for expensive laboratory-based pathology.
Nowadays genetic tests are flooding the market and many companies are trying to secure a piece of the pie including DermaGenoma (Irvine, CA). Claiming to bring the genetic revolution to dermatology, they have released a genetic test that predicts the risk of getting moderate to severe cellulite (or more specifically Nurnberger-Muller grade 2 or greater cellulite) for women. It tests for a variant of the angiotensin I-converting enzyme (ACE) gene located on chromosome 17. Given the fact that there is not much you can do to prevent it, even a perfect test seems to be of dubious value. Now, in the female half of our population 65% is affected. From the company’s own computations it turns out that a positive test result means 68% chance of getting cellulite, a whopping 3% increase, while if you test negatively you still have a 53% chance of getting it. While the company acknowledges all of this in its information for physicians, its marketing is more than likely to get at least some patients to persuade their doctors to offer the test.
Carbon nanotubes are already a major tool in bioscience research. In addition, these particles are finding themselves as a central component for production of variety of consumer products, from cosmetics to specialized plastics. Because of their intrinsic toxicity, though, there are still numerous questions about the safety of carbon nanotubes and how they’re processed by the human body.
Unbound Medicine has released the 12th edition of Davis’s Drug Guide for its mobile and online platform. The new edition is updated with the latest info on drugs, supplements, and drug epidemiological data.
In the continuing effort to make surgery less invasive, physicians at Johns Hopkins Hospital are operating on the brain through a tiny incision in one of the eyelids instead of lifting a large piece of the skull. Named transpalpebral orbitofrontal craniotomy, the procedure allows for access to the middle and front regions of the brain. The cranial cavity is reached through a hole created by removing a small, half-inch to one-inch-square section of skull bone right above the eyebrow. Endoscopic surgery can then be performed with help of previously obtained CT and MRI data. Afterwards, the dural defect is closed with a graft and the piece of bone is placed back in its original position. The procedure is shorter, less invasive and has fewer complications than conventional surgery. Because the incision is made in a natural crease of the eyelid, the resulting scar is hardly visible. So far the surgeons have performed repair of persistent cerebrospinal fluid leaks and pneumocephalus, and biopsy and resection of midline brain tumors in a total of seven patients.
The National Institutes of Health have awarded a $4 million grant to GE Global Research for further development of the company’s prototype fluorescent nerve labeling agent and imaging system. GE hopes the system will help surgeons prevent damage to nerve endings during prostate surgery by making the nerves more easily visible.
