Erika Ebsworth-Goold

 This passage is adapted from Erika Ebsworth-Goold,
“A Simple Sniff: Nanoparticle Research Tested in Locusts 
Focuses on New Drug-Delivery Method.” ©2017 by 
Washington University in St. Louis.
Delivering life-saving drugs directly to the brain 
in a safe and effective way is a challenge for medical 
providers. One key reason: the blood-brain barrier, 
which protects the brain from tissue-specific drug 
delivery. Methods such as an injection or a pill aren’t 
as precise or immediate as doctors might prefer, and 
ensuring delivery right to the brain often requires 
invasive, risky techniques.
A team of engineers from Washington University 
in St. Louis has developed a new nanoparticle 
generation-delivery method that could someday 
vastly improve drug delivery to the brain, making it 
as simple as a sniff.
“This would be a nanoparticle nasal spray, and the 
delivery system could allow a therapeutic dose of 
medicine to reach the brain within 30 minutes to one 
hour,” said Ramesh Raliya, research scientist at the 
School of Engineering & Applied Science.
“The blood-brain barrier protects the brain from 
foreign substances in the blood that may injure the 
brain,” Raliya said. “But when we need to deliver 
something there, getting through that barrier is 
difficult and invasive. Our non-invasive technique 
can deliver drugs via nanoparticles, so there’s less
risk and better response times.”
The novel approach is based on aerosol science 
and engineering principles that allow the generation 
of monodisperse nanoparticles, which can deposit on 
upper regions of the nasal cavity via diffusion. 
Working with Assistant Vice Chancellor Pratim 
Biswas, Raliya developed an aerosol consisting of 
gold nanoparticles of controlled size, shape and 
surface charge. The nanoparticles were tagged with 
fluorescent markers, allowing the researchers to track 
their movement.
Next, Raliya and biomedical engineering 
postdoctoral fellow Debajit Saha exposed locusts’ 
antennae to the aerosol, and observed the 
nanoparticles travel from the antennas up through 
the olfactory nerves. Due to their tiny size, the 
nanoparticles passed through the blood-brain
barrier, reaching the brain and suffusing it in a 
matter of minutes.
The team tested the concept in locusts because the 
blood-brain barriers in the insects and humans have 
anatomical similarities, and the researchers consider 
going through the nasal regions to neural pathways 
as the optimal way to access the brain.
“The shortest and possibly the easiest path to the 
brain is through your nose,” said Barani Raman, 
associate professor of biomedical engineering.
“Your nose, the olfactory bulb and then olfactory 
cortex: two relays and you’ve reached the cortex.
The same is true for invertebrate olfactory circuitry, 
although the latter is a relatively simpler system, with 
supraesophageal ganglion instead of an olfactory 
bulb and cortex.”
To determine whether or not the foreign 
nanoparticles disrupted normal brain function, Saha 
examined the physiological response of olfactory 
neurons in the locusts before and after the 
nanoparticle delivery. Several hours after the 
nanoparticle uptake, no noticeable change in the 
electrophysiological responses was detected.
“This is only a beginning of a cool set of studies 
that can be performed to make nanoparticle-based 
drug delivery approaches more principled,” Raman 
said.
The next phase of research involves fusing the 
gold nanoparticles with various medicines, and using 
ultrasound to target a more precise dose to specific 
areas of the brain.
“We want [targeted drug] delivery within the 
brain using this non-invasive approach,” Raliya said.

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