Tag Archives: Washington University in St. Louis (WUSTL)

All-natural agrochemicals

Michael Berger in his May 4, 2018 Nanowerk Spotlight article highlights research into creating all natural agrochemicals,

Widespread use of synthetic agrochemicals in crop protection has led to serious concerns of environmental contamination and increased resistance in plant-based pathogenic microbes.

In an effort to develop bio-based and non-synthetic alternatives, nanobiotechnology researchers are looking to plants that possess natural antimicrobial properties.

Thymol, an essential oil component of thyme, is such a plant and known for its antimicrobial activity. However, it has low water solubility, which reduces its biological activity and limits its application through aqueous medium. In addition, thymol is physically and chemically unstable in the presence of oxygen, light and temperature, which drastically reduces its effectiveness.

Scientists in India have overcome these obstacles by preparing thymol nanoemulsions where thymol is converted into nanoscale droplets using a plant-based surfactant known as saponin (a glycoside of the Quillaja tree). Due to this encapsulation, thymol becomes physically and chemically stable in the aqueous medium (the emulsion remained stable for three months).

In their work, the researchers show that nanoscale thymol’s antibacterial and antifungal properties not only prevent plant disease but that it also enhances plant growth.

“It is exciting how nanoscale thymol is more active,” says Saharan [Dr. Vinod Saharan from the Nano Research Facility Lab, Department of Molecular Biology and Biotechnology, at Maharana Pratap University of Agriculture and Technology], who led this work in collaboration with Washington University in St. Louis and Haryana Agricultural University, Hisar. “We found that nanoscale droplets of thymol can easily pass through the surfaces of bacteria, fungi and plants and exhibit much faster and strong activity. In addition nanodroplets of thymol have a larger surface area, i.e. more molecules on the surface, so thymol becomes more active at the target sites.”

Here’s a link to and a citation for the paper,

Thymol nanoemulsion exhibits potential antibacterial activity against bacterial pustule disease and growth promotory effect on soybean by Sarita Kumari, R. V. Kumaraswamy, Ram Chandra Choudhary, S. S. Sharma, Ajay Pal, Ramesh Raliya, Pratim Biswas, & Vinod Saharan. Scientific Reportsvolume 8, Article number: 6650 (2018) doi:10.1038/s41598-018-24871-5 Published: 27 April 2018

This paper is open access.

Final note

There is a Canadian company which specialises in nanoscale products for the agricultural sector, Vive Crop Protection. I don’t believe they claim their products are ‘green’ but due to the smaller quantities needed of Vive Crop Protection’s products, the environmental impact is less than that of traditional agrochemicals.

Locusts inspire new aerosol-based nanoparticle drug delivery system

Getting medication directly to the brain is a worldwide medical research goal and it seems that a team of scientists at the Washington University at St. Louis (WUSTL) has taken a step forward to accomplishing the goal. From an April 12, 2017 news item on ScienceDaily,

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.

Caption: Engineers at Washington University have discovered a new technique that could change drug delivery to the brain. They were able to apply a nanoparticle aerosol spray to the antenna of locusts, then track the nanoparticles as they traveled through the olfactory nerves, crossed the blood-brain barrier and accumulated in the brain. This new, non-invasive approach could someday make drug delivery as simple as a sniff for patients with brain injuries or tumors.

Credit: Washington University in St. Louis

An April 12, 2017 WUSTL news release by Erika Ebsworth-Goold (also on EurekAlert), which originated the news item, describes the work in more detail,

“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, chair of the Department of Energy, Environmental & Chemical Engineering and the Lucy & Stanley Lopata Professor, 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 brain-blood 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, which would be especially beneficial in brain-tumor cases.

“We want to drug target delivery within the brain using this non-invasive approach,” Raliya said.  “In the case of a brain tumor, we hope to use focused ultrasound so we can guide the particles to collect at that particular point.”

Here’s a link to and a citation for the paper,

Non-invasive aerosol delivery and transport of gold nanoparticles to the brain by Ramesh Raliya, Debajit Saha, Tandeep S. Chadha, Baranidharan Raman, & Pratim Biswas. Scientific Reports 7, Article number: 44718 (2017) doi:10.1038/srep44718 Published online: 16 March 2017

This paper is open access.

I featured another team working on delivering drugs directly to the brain via the olfactory system, except their nanoparticles were gelatin and they were testing stroke medication on rats, in my Sept. 24, 2014 posting.