Tag Archives: mosquitoes

Biosensors

Biosensors to shield against deadly epidemics

Featured image above: Macdonald (centre) with colleagues from the Programa de Estudio y Control de Enfermedades Tropicales (PECET) at the Universidad de Antioquia, Colombia

In April 2016, only two months after the World Health Organisation officially declared the Zika virus outbreak a Public Health Emergency of International Concern, a team of Australian experts in tropical medicine and mosquito-transmitted diseases travelled to Brazil and Colombia. 

Among the delegation, arranged by the Australian Trade and Investment Commission, was Associate Professor Joanne Macdonald from the University of the Sunshine Coast (USC) in Queensland. The molecular engineer, who also holds an appointment at Columbia University in New York City, has been developing point-of-care biosensors, similar to take-home pregnancy tests, to diagnose diseases. Importantly, these devices can rapidly detect the genomes of multiple diseases simultaneously, keeping costs down for diagnostic testing in areas where lots of diseases are co-occurring.  

With A$130,000 from the Bill and Melinda Gates Foundation, she and colleagues in Queensland have been working on a proof-of-concept to test mosquitoes for malaria, dengue and chikungunya. The test will also detect the bacterium Wolbachia. When introduced into Aedes aegypti mosquitoes, this potential control agent has been found to prevent viruses, including dengue and Zika, from being transmitted to people. 

Improving diagnosis during epidemics with biosensors

Biosensors
A/Prof Joanne Macdonald (far right) and colleagues observing vaccine and antidote production facilities at the Institute of Butantan, Sao Paulo (Credit: A/Prof Joanne Macdonald)

In Rio de Janeiro, Macdonald heard from local researchers how diagnostic testing labs were overwhelmed by the Zika virus epidemic. Clinics were only testing pregnant women, she was told, and results were taking up to two weeks to be returned. Furthermore, labs were having difficulty distinguishing between Zika and dengue, which are closely related, she says. 

In this environment, Macdonald’s biosensors could be a game-changer. Apart from reagent substances,  which trigger chemical reactions that ‘amplify’ DNA to detectable levels, the tests only require the most basic of lab equipment: a heating block and centrifuge (a piece of laboratory equipment, driven by a motor that spins liquid samples at high speed). This means tests can be easily performed in a doctor’s clinic or hospital with results returned inside an hour. 

“The scientists in Colombia and Brazil wanted the technology right then and there because there was such a dire need with the Zika outbreak,” she says. 

Since the trip, Macdonald has begun working on a test to specifically detect the genetic signature of the Zika virus, eliminating the potential for inconclusive results. Having already developed tests to detect Ebola, Japanese encephalitis, West Nile virus, and Hendra virus, which has killed nearly 100 horses in Australia over the last 23 years, Macdonald is confident it’s within reach.   

In a world where deadly disease vectors are increasingly mobile thanks to global transportation networks, Macdonald’s biosensors could become an important line of defence for future epidemics.  

“If we can provide solutions that allow testing to be done at the point-of-care, rather than in a central lab, that would be a big help,” Macdonald says. 

Macdonald has founded a startup called BioCifer to hold the intellectual property rights and commercialise the various technologies, and is currently working with USC to access the relevant intellectual property. With keen investors already in place, she’s hopeful a diagnostic product – initially for use in veterinary clinics and for research-only purposes – could be just two years away.   

Rapid detection vital to saving lives

Reproducing the detection sensitivity of state-of-the-art labs in a cost-effective, portable device is the ultimate goal of Macdonald’s research, and though it may be a decade away, she is making headway. In December 2015, she and her then PhD student Jia Li reported a world-first milestone in the journal Lab on a Chip, published by the Royal Society of Chemistry. 

They had developed a handheld, pregnancy test-style biosensor, which could detect up to seven different analytes, or theoretical diseases. What’s even more innovative is how the device notifies the end-user of the result: if DNA from a certain disease is detected it will light-up patterns of corresponding molecules or dots, like pixels on a computer screen. 

Inspired by the seven segment displays on digital watches, the dots are arranged to resemble the numbers 0 through 9. It’s the first time a numeric display like this has ever been demonstrated on a paper-based biosensor, known as a lateral flow device, and amazingly, it requires no external power source.

The biosensor “is powered entirely by molecules,” says Macdonald. “We are borrowing from computing, but using molecules instead of computer bits.” 

Programmed molecules play strategy games and make autonomous decisions

In 2006, while at Columbia University full-time, Macdonald and her colleagues built a computer out of DNA molecules. They programmed the DNA, modifying it to respond to stimulus, in order to play the strategy game tic-tac-toe interactively against a human. 

In the future, programmed molecules could be used to develop biological machines that operate inside the body, releasing drugs or insulin autonomously, on demand – something her US-based colleagues are working toward. Macdonald, is harnessing the capability of this technology to more rapidly detect deadly diseases. 

By embedding computing principles in molecules “we can decide whether they will turn on or off depending on the presence of other molecules around them,” she says. “So it’s like a chemical reaction based on logic, the molecules can make decisions on their own without any external inputs. And we pre-program them to do this.” This is how the dots in the biosensor know to light up. 

Biosensors
Macdonald inside a laboratory at the Instituto Colombiano de Medicina Tropical, Medellin, Colombia (Colombian Tropical Medicine Institute)(Credit: A/Prof Joanne Macdonald)

Catching the microbiology bug

A rare illness in high school called coxsackievirus, which affected Macdonald’s heart muscles and prevented her from participating in sport, helped spur a lifelong fascination with disease. After she recovered, her interest blossomed at the University of Queensland. While there she majored in biochemistry and microbiology, and later completed a PhD investigating the West Nile virus under the supervision of immunoassay expert Professor Roy A. Hall, who she is still collaborating with.

Macdonald went on to spend 10 years at Columbia University, first in the lab of  Professor Ian W. Lipkin, an epidemiologist who was the scientific adviser for the Hollywood blockbuster Contagion, and then working with two “humongous scientific minds” in Professors Donald W. Landry and Milan N. Stojanovic. Under their guidance she not only programmed DNA molecules to play tic-tac-toe, but also helped develop a drug that inactivates cocaine, which is now being trialled as a treatment for overdoses. 

Back in Australia since 2012 and focused primarily on rapid disease detection, Macdonald is thinking about the next big question as point-of-care and biosensor technologies advance: “Can we actually predict epidemics before they start?” 

In the future, she wants her biosensors to effectively act as shields, used pre-emptively by aid agencies and community members to screen their surroundings, including potential hosts of infectious diseases such as bats, monkeys and mosquitoes, before outbreaks occur. She hopes it might empower communities, enabling them to take precautions before they get sick, and ultimately save lives. 

– Myles Gough

This article on biosensors was first published by Australia Unlimited on 19 January 2017. Read the original article here.

Love Hertz

Love Hertz

James Cook University researchers have found sex sells when it comes to luring male mosquitoes.

Senior Research Officer Brian Johnson and Professor Scott Ritchie set out to make a cheap and effective audio lure for scientists collecting male Aedes aegypti mosquitoes – the species that carries dengue and yellow fever.

They found a tone of precisely 484 Hertz, the frequency of a female Aedes aegypti’s wings, brought 95% of male mosquitoes to the trap.

Johnson says the device cost around $20 and could be run by itself for weeks. “We started with a cheap mobile phone and moved to an even cheaper MP3 player. There are no harmonics, it’s a pure tone and very simple to produce.”

Love Hertz

The effectiveness of the audio lure is easy to see: when it’s switched on, mosquitoes flock to the device, and fly away as soon as it’s turned off, as can be seen in the video.

The invention of the audio trap is timely: male mosquitoes do not bite, but new anti-mosquito strategies involve capturing and sterilising them before releasing them to breed unsuccessfully with females.

“There are a number of projects underway,” says Johnson. “They required capturing and releasing tens of thousands of male mosquitoes, but most traps are aimed at capturing females.”

 

He says there was no chance of eliminating mosquito populations by trapping males alone, as only a few needed to survive to continue the breeding cycle.

The scientists also found that female mosquitoes were completely oblivious to the sound of male wing beats. “There’s no real need for females to respond to male overtures,” says Johnson.

The team is now optimising the trap for field use and coordinating with trap manufacturers to add the feature to their products.

This article was first published by James Cook University on 6 January 2016. Read the original article here.

Grand Challenges Explorations

Dengue research gets Grand Challenges Explorations grant

The University of Queensland announced today that it is a Grand Challenges Explorations winner, an initiative funded by the Bill & Melinda Gates Foundation. Research groups led by Professor Paul Young of the School of Chemistry and Molecular Biosciences, and Professor Matt Cooper at UQ’s Institute for Molecular Bioscience will pursue an innovative global health and development research project, titled Next-gen diagnostics for field-based surveillance of Wolbachia and arboviral infections in wild mosquitoes.

Grand Challenges Explorations (GCE) funds individuals worldwide to explore ideas that can break the mould in how we solve persistent global health and development challenges. Young and Cooper’s project is one of more than 50 Grand Challenges Explorations Round 15 grants announced today by the Bill & Melinda Gates Foundation.

To receive funding, Young and Cooper and other Grand Challenges Explorations winners demonstrated in a two-page online application a bold idea in one of five critical global heath and development topic areas. The foundation will be accepting applications for the next GCE round in March 2016.

The project aims to develop a portable tool to detect mosquitoes carrying dengue fever. Dengue virus is estimated to infect up to 400 million people globally each year. The next-generation diagnostic tool, which can be used in a field setting, uses quantum dot nanoparticles in a simple, cheap assay to measure the presence of a dengue virus protein. The test is also able to detect Wolbachia carrying mosquitoes. Wolbachia is a naturally occuring bacterium that has been added to mosquitoes to reduce their susceptibility to dengue and other viruses. “The idea is to test mosquitoes in the field for the presence of dengue as an early warning surveillance system,” Young says.

“We need to get the best tests we have out of the lab and into the field, where they can help identify dengue and track prevention measures in real time.  Identifying hot spots early could help us get on top of epidemics before they break out,” says Cooper.

UQ Alumnus Dr Joanne Macdonald of the University of the Sunshine Coast is also a Global Challenges Exploration winner, and will pursue a project entitled: A rapid field test for detecting infected mosquitoes.  Project team members include her former supervisor Professor Roy Hall of UQ’s School of Chemistry and Molecular Biosciences. Macdonald has developed a simple diagnostic test able to detect multiple pathogens that reduces costs compared to performing individual assays, and does not require specialised equipment.


About Grand Challenges Explorations

Grand Challenges Explorations is a US$100 million initiative funded by the Bill & Melinda Gates Foundation. Launched in 2008, over 1160 projects in more than 60 countries have received Grand Challenges Explorations grants. The grant program is open to anyone from any discipline and from any organisation. The initiative uses an agile, accelerated grant-making process with short two-page online applications and no preliminary data required. Initial grants of US$100,000 are awarded two times a year. Successful projects have the opportunity to receive a follow-on grant of up to US$1 million.


The University of Queensland


The University of Queensland (UQ) is one of Australia’s leading research and teaching institutions, ranked in the world’s top 50 by the QS World University Rankings and the Performance Ranking of Scientific Papers for World Universities. The University is the oldest and largest in Queensland, with 50,000-plus students engaged in more than 400 degree programs. UQ has been educating people to create change for a better world for more than a century, producing more than 225,000 graduates since opening in 1911, including more than 11,500 PhDs, a Nobel laureate, the CEO of a Fortune 500 company and leaders in government, law, science, public service and the arts.

This article was first published by the University of Queensland on 13 November 2015. Read the original article here.