Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Proteins in Focus

15.12.2011
Adjustable protein microlenses made by femtosecond laser direct writing

Whether it’s right under our nose or far away, when we observe an object we see it—provided we have healthy eyes and normal vision or suitable glasses—in focus. For this to work, muscles deform the lenses of our eyes and adjust them to a suitable focal distance.

For miniaturized technical devices, microscale lenses with a similar adaptable focus could be an advantage. In the journal Angewandte Chemie, Hong-Bo Sun and a team from Jilin University (China) have described a new approach to the production of adjustable microlenses made from protein gels.

Proteins are potentially useful as “building materials” for microcomponents because they are readily available, inexpensive, and biocompatible. They can also change their properties in response to external stimuli, which makes them an interesting material for use in adjustable microlenses. However, lenses must be extremely precise in order to meet optical requirements—something difficult to achieve with proteins. In addition, they must be fast, simple, and inexpensive to produce.

The Chinese researchers have now met this challenge: They used a laser to “write” the desired micrometer-sized lens shape out of a solution of bovine serum albumin, a protein. Methylene blue acts as a photosensitizer, which captures the light energy like an antenna and triggers a crosslinking reaction of the protein molecules. Driven by a computer, the laser cuts out the desired three-dimensional form voxel by voxel. A voxel is a three-dimensional pixel, a tiny segment of volume. The irradiation used is in femtosecond pulses, which lasts on the order of 10-13 seconds. The crosslinking reaction only takes place in the locations that are irradiated. After the reaction, the protein molecules that have not reacted can simply be rinsed away. What stays behind is a cross-linked, aqueous protein gel in the shapes of micrometer-sized lenses.

Direct writing with lasers usually results in structures that have too rough a surface for optical applications. By optimizing the duration of the laser pulse, the pulse intensity, and the protein concentration, Sun and his team obtained lenses with outstanding optical properties.

The special trick in this case is that the amount of liquid absorbed by the protein gel depends on the pH value of the solution. Increasing the pH causes the lens to swell. If the increase in thickness is limited by a glass surface, the lens primarily grows in width and becomes flatter. If the pH value is reduced, the gel shrinks and the lens is more curved. Because the radius of curvature determines the focal length of the lens, this method can be used to focus the microlenses.

Because the protein lenses are biocompatible, they may be used in optical analytical systems for medical diagnostics or lab-on-a-chip technology.

About the Author
Dr Hong-Bo Sun is a Changjiang Professor at Jilin University, China. His main specialty is laser micronanofabrication, by which various micro-optical, microelectronic, micromechnical, microfludic, and biomimetic structures and devices have been designed and fabricated in his group.
Author: Hong-Bo Sun, Jilin University, Changchun (China), http://www.lasun-jlu.cn/people.php
Title: Dynamically Tunable Protein Microlenses
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201105925

Hong-Bo Sun | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht Biophysicists reveal how optogenetic tool works
29.05.2020 | Moscow Institute of Physics and Technology

nachricht Mapping immune cells in brain tumors
29.05.2020 | University of Zurich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

Black nitrogen: Bayreuth researchers discover new high-pressure material and solve a puzzle of the periodic table

29.05.2020 | Materials Sciences

Argonne researchers create active material out of microscopic spinning particles

29.05.2020 | Materials Sciences

Smart windows that self-illuminate on rainy days

29.05.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>