Skip to Content

How Cocoons Are Turned Into Optical Devices

A simple process turns cocoons into optical devices with biological applications.
December 22, 2008
Preda stirs cut-up cocoons in a salt solution. The cocoons are boiled in a beaker over a hot plate to dissolve the protein that holds them together, sericin. The silk fibers, now pure fibroin protein, will be dissolved in another salt solution.
Using a syringe, Preda loads the syrupy silk solution into a dialysis cartridge. The cartridge will be placed in a beaker of water, which will draw the salt out through the cartridge’s clear window. Finally, Preda will use a syringe to suck out the pure water-fibroin solution left behind, which she’ll store in the fridge.
To make a hologram, a researcher deposits the water-based solution of pure silk fibroin onto a mold with a pipette. Fibroin makes a good optical material because it’s translucent when it dries, and it conforms well to both the nanoscale and macro­scale details of molds like this one.
After drying for several hours, silk optical devices like the hemoglobin-containing card in the researcher’s left hand can be peeled off their molds. Each iridescent square has been molded into a different device. One is a diffraction grating that can act as an oxygen sensor.

Keep Reading

Most Popular

AV2.0 autonomous vehicles adapt to unknown road conditions concept
AV2.0 autonomous vehicles adapt to unknown road conditions concept

The big new idea for making self-driving cars that can go anywhere

The mainstream approach to driverless cars is slow and difficult. These startups think going all-in on AI will get there faster.

biomass with Charm mobile unit in background
biomass with Charm mobile unit in background

Inside Charm Industrial’s big bet on corn stalks for carbon removal

The startup used plant matter and bio-oil to sequester thousands of tons of carbon. The question now is how reliable, scalable, and economical this approach will prove.

images created by Google Imagen
images created by Google Imagen

The dark secret behind those cute AI-generated animal images

Google Brain has revealed its own image-making AI, called Imagen. But don't expect to see anything that isn't wholesome.

AGI is just chatter for now concept
AGI is just chatter for now concept

The hype around DeepMind’s new AI model misses what’s actually cool about it

Some worry that the chatter about these tools is doing the whole field a disservice.

Stay connected

Illustration by Rose WongIllustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.