Dengue fever vaccine delivered with nanotechnology targets all four virus serotypes – University of North Carolina Research


denguefeverCredit: CC0 Public Domain

The latest in a series of studies led by the Aravinda de Silva Lab at the UNC School of Medicine shows continued promise in a dengue virus vaccine delivered using nanoparticle technology.

 

Each year, an estimated 25,000 people die from dengue infections and millions more are infected. Scientists have been trying to create a  for many years, but creating an effective  is challenging due to the four different serotypes of the virus. For a person to be fully protected against dengue, they need to be vaccinated against all four serotypes at once – something current vaccines do not achieve. In their paper published in PLOS Neglected Tropical Diseases, Aravinda de Silva, Ph.D., professor of microbiology and immunology, and UNC research associate Stefan Metz, Ph.D., detail how their nanoparticle delivery platform is producing a more balanced immune  versus other vaccine delivery platforms.

To deliver the vaccine, the de Silva lab is using a nanoparticle platform produced with PRINT (Particle Replication in Non-wetting Templates) technology, which was developed by Joseph DeSimone, Ph.D., the Chancellor’s Eminent Professor of Chemistry at UNC-Chapel Hill, with an appointment in the department of pharmacology. Rather than using a killed or attenuated virus to develop a vaccine for , researchers are focusing on expressing the E protein and attaching it to  to induce good immune responses. In previous studies of monovalent vaccines, they have shown that the platform can induce protective immune response in individual serotypes. Their latest study of a tetravalent vaccine shows the response in all four serotypes at the same time.

“We are also seeing a more balanced immune response for each of the serotypes, which means the quality of neutralizing antibodies created is leading to a better overall protective reaction for the patient,” said Metz, the paper’s lead author.

The de Silva lab performed the experiments on their Dengue vaccine in close collaboration with co-author Shaomin Tian, Ph.D., research assistant professor in the department of microbiology and immunology. The proteins used in the experiments were produced by the UNC Protein Expression and Purification (PEP) core.

The de Silva lab’s next steps include optimizing the technique they use to attach the E protein to the nanoparticle. This work will be extremely important when trying to create a vaccine that induces consistently strong protective immune responses.

 Explore further: Nanoparticle vaccinates mice against dengue fever

More information: Stefan W. Metz et al. Nanoparticle delivery of a tetravalent E protein subunit vaccine induces balanced, type-specific neutralizing antibodies to each dengue virus serotype, PLOS Neglected Tropical Diseases (2018). DOI: 10.1371/journal.pntd.0006793

Advertisements

Nano-particles Release Insulin into Diabetics’ Bloodstream


QDOTS imagesCAKXSY1K 8Diabetics could cut their need for injections to less than once a week thanks  to new insulin-releasing “smart” particles.

Researchers in the US have developed a type of nanoparticle that  automatically releases insulin into the blood when glucose levels get too high,  and have demonstrated that its effects last for 10 days in mice.

Regular injections of the particles could mean type 1 diabetics  wouldn’t have to check their blood sugar levels several times a day, or inject  the exact right amount of insulin when needed, which can result in too high or  low doses being administered, with further health problems following.

click here

‘We’ve created a ‘smart’ system that is injected into the body and  responds to changes in blood sugar by releasing insulin, effectively controlling  blood-sugar levels,’ said Dr Zhen Gu, an assistant professor in the joint  biomedical engineering program at North Carolina State University and the  University of North Carolina.

‘This technology effectively creates a ‘closed-loop’ system that mimics  the activity of the pancreas in a healthy person, releasing insulin in response  to glucose level changes. This has the potential to improve the health and  quality of life of diabetes patients.’

The nanoparticles have a solid core of insulin surrounded by a layer of  a modified glucose-based material known as dextran and another of glucose  oxidase enzymes.

When the enzymes are exposed to high glucose levels they effectively  convert the sugar into gluconic acid, which breaks down the modified dextran and  releases the insulin.

The insulin then brings the glucose levels under control. The gluconic  acid and dextran are biocompatible and dissolve in the body.

The nanoparticle cores are given a biocompatible coating that makes  them positively or negatively charged, causing them to form a network that  prevents them from dispersing throughout the body.

The positively charged coatings are made of chitosan (a material  normally found in shrimp shells), abnd the negatively charged coatings are made  of alginate (a material normally found in seaweed).

When the solution of coated nanoparticles is mixed together, the  positively and negatively charged coatings are attracted to each other to form a “nano-network.”

Once injected into the subcutaneous layer of the skin, the nano-network  holds the nanoparticles together. Both the nano-network and the coatings are  porous, allowing blood – and blood sugar – to reach the nanoparticle cores.

Gu’s research team is now in discussions to move the technology into  clinical trials for use in humans.

A paper on the research has been published in the scientific journal  ACS Nano.

Read more:  http://www.theengineer.co.uk/medical-and-healthcare/news/smart-particles-release-insulin-into-diabetics-bloodstream/1016213.article#ixzz2ScNHSXmx