Biomedical engineers from Tufts University have developed an edible and biodegradable optical sensor made from silk that could be used to detect contaminants in food at the grocery store, monitor glucose or pH levels in a patient’s blood, or create a new type of solar cell.
Mulberry silkworm cocoons are used to extract the silk for the new material. Different patterns have been etched into a demonstration sheet of the silk optical material.
Fiorenzo Omenetto, associate professor of physics and biomedical engineering at Tufts and director of the Ultrafast Nonlinear Optics and Biophotonics Group, will discuss the innovation at the Hot Topics session at BiOS, part of SPIE Photonics West, Saturday, 24 January in San Jose, CA. Omenetto’s talk on biodegradable silk optics will be one of eight Hot Topics presentations on cutting-edge clinical and technical advances at the world’s largest biomedical technologies event.
The novel, silk-based optics developed by Omenetto and David Kaplan, chairman of biomedical engineering at Tufts, are made from strong fibers harvested from the cocoons of mulberry silkworms. The material looks like clear plastic with a laser-imprinted pattern that defines its use.
To make the material, Omenetto and his team boiled silk threads in a water solution to extract glue-like sericin proteins. The liquefied silk then was poured into a mold of nonhygroscopic material such as glass or plastic, with ruled and holographic diffraction gratings spaced as fine as 3600 grooves per millimeter. The material uses no toxic chemicals and can be stored at room temperature.
“We wait for it to crystallize and dry, and we peel it off and use that,” Omenetto says.
The researchers have applied for patents on the silk-based optics and are actively exploring commercialization opportunities. One of the more intriguing applications is to use silk optics to determine if food products have been tainted by bacteria. Omenetto’s team has shown that the silk optic material could be patterned as a series of nanoscale peaks and troughs, with something that would react to the bacteria inserted into each trough. If the bacteria were present, the troughs would fill and—like a butterfly wing when its structure is altered—change colors, signaling the presence of bacteria.
Their research was published in the journal Biomacromolecules.
A hologram with the Tufts University logo was created using the silk optical material.
The Hot Topics session at BiOS will be moderated by Sergio Fantini, also at the Department of Biomedical Engineering at Tufts, and feature remarks by Symposium chairs James Fujimoto and R. Rox Anderson.
Kishan Dholakia, professor of physics at the University of St. Andrews (UK), will also deliver a Hot Topics presentation on advanced studies in photoporation. Laser-based photoporation and transfection is an emerging technique for delivering therapeutic agents to biological cells in a targeted and sterile manner, without affecting neighboring cells. Dholakia is head of the Optical Trapping Group within the School of Physics and Astronomy at St. Andrews.
Other presenters will discuss advances in cancer diagnosis and treatment, treatments for stroke, and work with stem cells. They include:
Chris Contag, associate professor and co-director of the Molecular Imaging Program at Stanford University (USA), Targeting the Cancer Stem Cell
SPIE Fellow Jennifer K. Barton, associate professor and director of biomedical engineering at the University of Arizona (USA), OCT and Fluorescence Spectroscopy for Cancer Detection
Arjun G. Yodh, James M. Skinner professor of science at the University of Pennsylvania (USA), Diffuse Optics for Acute Stroke Management
Stefan W. Hell, director of nanobiophotonics at Max-Planck-Institut für Biophysikalische Chemie (Germany), Nanoscopy with Far-Field Optics
Charles P. Lin, associate professor at the Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School (USA), Tracking Stem Cells In Vivo
Summer L. Gibbs-Strauss, a post-doctoral fellow at Beth Israel Deaconess Medical Center (USA), First-in-Human Clinical Trial of the FLARE Image-Guided Surgery System
Nobel Winner at BiOS
Nobel Prize winner Roger Tsien, professor of pharmacology at the University of California, San Diego, is the author of two of 1500 technical papers to be presented at the BiOS symposium in January.
The 2008 Nobel Prize in chemistry was awarded to Tsien, Osamu Shimomura, emeritus professor at the Marine Biological Laboratory in Woods Hole, MA, and Martin Chalfie of Columbia University, NY, for utilizing the ability of some jellyfish to glow green as a tool for observing protein activity in living cells. Tsien will present papers on fluorescent proteins at BiOS.
San Jose, CA (USA)
1500+ technical papers
Exhibit open 24-25 January
Web site: spie.org/bios
5 program tracks
• Photonic Therapeutics and Diagnostics
• Clinical Technologies and Systems
• Tissue Optics, Laser-Tissue Interaction, and Tissue Engineering
• Biomedical Spectroscopy, Microscopy, and Imaging
James Fujimoto, MIT
R. Rox Anderson, MGH and Harvard
“Biophotonics: Light Tools for Cancer” is the subject of one of 14 free posters that SPIE offers in an effort to increase awareness about the importance of optics and photonics and their applications. More information: spie.org/posters