What
a University of Central Florida student thought was a failed experiment
has led to a serendipitous discovery hailed by some scientists as a
potential game changer for the mass production of nanoparticles.
Soroush
Shabahang, a graduate student in CREOL (The College of Optics &
Photonics), made the finding that could ultimately change the way
pharmaceuticals are produced and delivered.
The
discovery was based on using heat to break up long, thin fibers into
tiny, proportionally sized seeds, which have the capability to hold
multiple types of materials locked in place. The work, published in the
July 18 issue of Nature, opens the door to a world of applications.
Craig
Arnold, associate professor of Mechanical and Aerospace Engineering at
Princeton University and an expert in laser material interactions who
did not work on the project, said no one else in the field has been able
to accomplish that feat.
With
a new non-chemical method of creating identical particles of any size
in large quantities, “the possible applications are up to your
imagination,” Arnold said.
The
most immediate prospect is the creation of particles capable of drug
delivery that could, for example, combine different agents for fighting a
tumor. Or it could combine a time-release component with medications
that will only activate once they reach their target – infected cells.
“With
this approach you can make a very sophisticated structure with no more
effort than creating the simplest of structures,” said Ayman Abouraddy,
an assistant professor at CREOL and Shabahang’s mentor and advisor.
Abouraddy has spent his career, first at the Massachusetts Institute of
Technology and now at UCF, studying the fabrication of multimaterial
fibers.
The
technique relies on heat to break molten fibers into spherical
droplets. Imagine water dripping from a faucet. Glass fibers are perhaps
best known as the cylindrical cables that transmit digital information
over long distances. For year, scientists have been looking for ways to
improve the purity of glass fibers to allow for faster, disruption-free
transmission of light waves.
Shabahang
and fellow graduate student Joshua Kaufman were working on just such a
project, heating and stretching glass fiber on a homemade tapering
machine. Shabahang noticed that instead of the desired result of making
the center of the cable thinner, the material actually broke apart into
multiple miniature spheres.
“It was kind of a failure to me,” Shabahang said.
However, when Abouraddy heard what had happened he knew right away that this “mistake” was a major breakthrough.
While
at MIT, Abouraddy and his mentor, Yoel Fink, a professor of materials
science and current director of MIT’s Research Laboratory of
Electronics, said they were told by a theoretician that molten optical
fiber should align with a process known as Rayleigh instability, which
explains what causes a falling stream of fluid to break into droplets.
At
the time, the MIT group was focused on producing fibers containing
multiple materials. The team produced fibers by heating a scale model
called a “preform” and stretching it apart much the way taffy is made.
The process is known as thermal drawing.
Shabahang’s
experiment shows that by heating and then cooling multimaterial fibers,
the theoretical became reality. Uniform particles that look like
droplets are produced. Moreover, Shabahang demonstrated that once the
spheres form, additional materials can be added and locked into place
like LEGO building blocks, resulting in particles with sophisticated
internal structures.
Especially
significant is the creation of “beach ball” particles consisting of two
different materials melded together in alternating fashion, similar to
the stripes on a beach ball.
Kaufman, Shabahang and Abouraddy contributed to the Nature
article in addition to Guangming Tao from CREOL, UCF; Esmaeil-Hooman
Banaei from the Department of Electrical Engineering & Computer
Science, UCF; Daosheng S. Deng, Department of Chemical Engineering, MIT;
Xiangdong Liang, Department of Mathematics, MIT; Steven G. Johnson,
Department of Mathematics, MIT; and Yoel Fink from MIT.
Structured spheres generated by an in-fibre fluid instability
Source: University of Central Florida
Filed Under: Drug Discovery
