Small Nanoparticles Bring Big Improvement to Medical
Imaging
More on Nano-Bots and Nano-Partuicles being used more and
more in medicine and other products – As reported these are in Sun Tan Lotions –
but more importantly these Nano-Bots and Nano-Particles are being found to be
lodged in peoples brains and in other organs of the body. These things do not simply disappear or pass
from our bodies, and perhaps they do not simply die either.
BiologyNet News
If you're
watching the complex processes in a living cell, it is easy to miss something
important—especially if you are watching changes that take a long time to
unfold and require high-spatial-resolution imaging. But new research* makes it
possible to scrutinize activities that occur over hours or even days inside
cells, potentially solving many of the mysteries associated with
molecular-scale events occurring in these tiny living things.
A joint research team, working at the National Institute of
Standards and Technology (NIST) and the National Institute of Allergy and
Infectious Diseases (NIAID), has discovered a method of using nanoparticles to
illuminate the cellular interior to reveal these slow processes. Nanoparticles,
thousands of times smaller than a cell, have a variety of applications. One
type of nanoparticle called a quantum dot glows when exposed to light. These
semiconductor particles can be coated with organic materials, which are
tailored to be attracted to specific proteins within the part of a cell a
scientist wishes to examine.
"Quantum dots last longer than many organic dyes and
fluorescent proteins that we previously used to illuminate the interiors of
cells," says biophysicist Jeeseong Hwang, who led the team on the NIST
side. "They also have the advantage of monitoring changes in cellular
processes while most high-resolution techniques like electron microscopy only
provide images of cellular processes frozen at one moment. Using quantum dots,
we can now elucidate cellular processes involving the dynamic motions of
proteins."
For their recent study, the team focused primarily on
characterizing quantum dot properties, contrasting them with other imaging
techniques. In one example, they employed quantum dots designed to target a
specific type of human red blood cell protein that forms part of a network
structure in the cell's inner membrane. When these proteins cluster together in
a healthy cell, the network provides mechanical flexibility to the cell so it
can squeeze through narrow capillaries and other tight spaces. But when the cell gets infected with the malaria parasite, the
structure of the network protein changes.
"Because the clustering mechanism is not well understood,
we decided to examine it with the dots," says NIAID biophysist Fuyuki
Tokumasu. "We thought if we could develop a technique to visualize the
clustering, we could learn something about the progress of a malaria infection,
which has several distinct developmental stages."
The team's efforts revealed that as the membrane proteins
bunch up, the quantum dots attached to them are induced to cluster themselves
and glow more brightly, permitting scientists to watch as the clustering of
proteins progresses. More broadly, the team found that when quantum dots attach
themselves to other nanomaterials, the dots' optical properties change in
unique ways in each case. They also found evidence that quantum dot optical
properties are altered as the nanoscale environment changes, offering greater
possibility of using quantum dots to sense the local biochemical environment
inside cells.
"Some concerns remain over toxicity and other
properties," Hwang says, "but altogether, our findings indicate that
quantum dots could be a valuable tool to investigate dynamic cellular
processes."