The most complex pattern described as "ramen-noodle-like" by the researchers was formed using viral concentrations ranging from 4-6 milligrams per milliliter. By using the Advanced Light Source at LBNL, the researchers discovered that this highly ordered structure could bend light like a prism in ways never before observed in nature or other engineered materials.
"We can determine the type of structure we get through this technique by fine-tuning the factors that influence the kinetics and thermodynamics of the assembly process," said Chung. "We can control the levels of order, direction of the twist, as well as the width, height and spacing of the film patterns."
The researchers further showed that the virus assembly process could be used in biomedical applications. They genetically engineered the virus to express specific peptides, which influence the growth of soft and hard tissue. They used the resulting viral films as tissue-guiding templates for the biomineralization of calcium phosphate, forming a tooth-enamel like composite that in the future could be applied as a regenerative tissue material.
The simplicity of the technique bodes well for adapting it for use in manufacturing, the researchers said. Once the parameters are set, it is possible to step aside and let the self-assembly process take place.
"We let this run overnight, and by the next morning there were trillions of viral filaments arranged in patterns on our substrate," said Lee. "One of the most important aspects of our work is that we have started to understand nature's approach to creating such complex structures, and we have developed an easy way to mimic and even extend it."
|Contact: Sarah Yang|
University of California - Berkeley