technique used to build micro-polymeric structure
on a human hair, without harming it
First demonstration that 'MAP'
laser technique can be used non-destructively on
biomaterials; potential applications range
from medical research to fiber optics
HILL, MA (5-3-04) -- Researchers in the laboratory of
Boston College Chemistry Professor John T. Fourkas have
demonstrated the fabrication of microscopic polymeric
structures on top of a human hair.
Fourkas, in collaboration with Boston College Physics
Professor Michael J. Naughton and Professors Malvin
C. Teich and Bahaa E. A. Saleh of the Department of
Electrical and Computer Engineering at Boston University,
used a technique called multiphoton-absorption photopolymerization
(MAP), in which a polymer can be deposited at the focal
point of a laser beam; scanning of the laser beam in
a desired pattern then allows for the formation of intricate,
three-dimensional patterns. This technique, also being
explored by a handful of other groups worldwide, makes
it possible to create features that are 1000 times smaller
than the diameter of a human hair.
These new results show for the first time that MAP can
be used to fabricate structures nondestructively on
biomaterials, and point the way towards applications
of MAP in the creation of miniature biodevices, which
could include micromanipulators for cells or even individual
protein or DNA molecules.
The findings will be published in the June 1 issue of
Journal of Applied Physics.
The original purpose of the study was to demonstrate
that intricate and resilient structures could be created
with MAP using inexpensive and readily-available materials.
In order to demonstrate the size of the features that
could be created, the researchers fabricated structures
near a human hair, and in the course of these experiments
they discovered that it was also possible to fabricate
structures on the hair itself.
"We built the structure on top of the hair with
a material that is akin to plexiglass," said Fourkas.
"One of the really exciting and unexpected things
about this is that we found that we could make this
structure on the hair without harming it in any way.
This suggests that we could accomplish the same with
other biological materials. One could imagine, for instance,
building devices directly on skin, blood vessels, and
eventually even a living cell. While this idea is currently
in the realm of science fiction, our results represent
an important step in that direction.
"On the level of individual cells, one can imagine
making devices that can tether cells to a surface or
to each other, or that allow the delivery of particular
chemicals to the cell, or that monitor processes within
the cell," explained Fourkas. "On a larger
scale, if the same sort of structures can be constructed
from biocompatible materials one can imagine applications
in drug delivery and medical monitoring, among other
Three-dimensional structures created with this technique
also have the potential to be used in other miniature
devices, such as optical communications hardware: fiber
optics and the hardware that is used to interface them
"While there are applications of the technique
we used in the optical communications area that are
being pursued by us and by others, writing a structure
on a hair does not have direct bearing on optical communications,"
Fourkas said. "On the other hand, we can and have
done exactly the same sort of thing on optical fibers
that are of comparable size, and this does have direct