The new process is based on the use of visible light, ultra short pulse laser. When focused inside photopolymerizable material the radiation causes a reaction, where two photons are absorbed simultaneously, thus leading to the polymerization of the material. One of the advantages of this so called two-photon polymerization process is that the fabrication occurs below the surface of liquid material, and the polymerization is confined only to the point of focus whose diameter can be much less than 1 micrometer. The conventional ultraviolet light induced polymerization causes hardening of the material along the entire path of the UV-beam, thus making it impossible to form very small three dimensional features. The two photon polymerization process requires no utilization of special photolithographic masks since the structure is formed directly inside the liquid volume.
High accuracy biomaterial structures need to be used as tissue engineering scaffolds or cell culture platforms where the fine features have to follow the dimensions of the cultured cells. So far the smallest features achieved in this project have been about 700 nanometers wide. As a reference one can compare it to the epithelial cells, which have a diameter of 11000 - 12000 nm or viruses that range in size between 10 - 100 nm. The fabricated structures can be made of biodegradable materials and thus are biocompatible. The process can also be utilized in manufacturing structures for other applications, e.g. optical waveguides, photonic crystals, and microfluidic channels.
Another advantage of this process is the possibility to utilize an inexpensive, low-power laser. Other research groups have typically used very expensive femtosecond titanium-sapphire pulse lasers. A much cheaper laser that produces longer, picoseconds width pulses has been used in the project. As far as is known there is only one research group in the USA, that has previously succeeded in polymerizing biomaterials with a similar system.
The project has been accomplished as an interdisciplinary collaboration. Research Scientist Sanna Peltola from the Institute of Biomaterials, Tampere University of Technology has been responsible of the development of materials, and the research group of Research Professor Jouko Viitanen from VTT has developed the laser system. The stem cell culturing requirements have been specified by the researchers of the Tampere University. Nanofoot Finland Oy is commercializing the new process. The company offers versatile services in the area of laser machining.
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UNH scientists help provide first-ever views of elusive energy explosion
16.11.2018 | University of New Hampshire
NASA keeps watch over space explosions
16.11.2018 | NASA/Goddard Space Flight Center
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
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