Bioengineers and public health researchers have developed a novel spray drying method for preserving and delivering the most common tuberculosis (TB) vaccine. The low-cost and scaleable technique offers several potential advantages over conventional freezing procedures, such as greater stability at room temperature and use in needle-free delivery. The spray drying process could one day provide a better approach for vaccination against TB and help prevent the related spread of HIV/AIDS in the developing world.
The research team led by Yun-Ling Wong, a graduate researcher in bioengineering, and David Edwards, Gordon McKay Professor of the Practice of Biomedical Engineering, both at the Harvard School of Engineering and Applied Sciences, and Barry R. Bloom, Dean of the Harvard School of Public Health and Joan L. and Julius H. Jacobson Professor of Public Health, was sponsored in part by the Bill and Melinda Gates Foundation. The work appeared in the February 13 edition of the Proceedings of the National Academy of Sciences.
"With the increasing incidence of tuberculosis and drug resistant disease in developing countries due to HIV/AIDS, there is a need for vaccines that are more effective than the present Bacillus Calmette-Guérin (BCG) vaccine," said Wong. "An optimal new vaccine would obviate needle injection, not require refrigerated storage, and provide a safe and more consistent degree of protection."
BCG, while the most widely administered childhood vaccine in the world, with 100 million infant administrations annually, is presently dried by freezing—or lyophilization —and delivered by needle injection. The commercial formulation requires refrigerated storage and has shown variable degrees of protection against tuberculosis in different parts of the world. Because of such limitations, public health experts and physicians have long seen a need for alternatives to the traditional BCG vaccine and current treatment strategies.
"The breakthrough for developing the spray drying process involved removing salts and cryoprotectants like glycerol from bacterial suspensions," explains Edwards. "This is counter to conventional thinking: that bacteria be dried in the presence of salts and cryoprotectants. While these substances are generally required for normal storage and freezing protocols, in the case of evaporative drying as occurs in spray drying, salt and cryoprotectants act like knives that press on the bacterial membrane with great force and inactivate the bacteria. By removing these, we managed to save the bacteria and achieve better stability."
The spray drying process developed for the BCG vaccine is similar to the way manufacturers prepare powdered milk. In fact, Edwards' first exposure to the spray drying process occurred when he was working with a spray dryer to produce highly respirable drug aerosols in a food science lab. While spray drying of small and large molecules is common in the food, cosmetic and pharmaceutical industries, the method has not been commonly used for drying cellular material. Most important, the new technique enables the BCG vaccine, and potentially other bacterial and viral based vaccines, to be dried without the traditional problems associated with standard freezing.
"Unlike traditional freezing techniques, spray drying is lower cost, easily scaleable for manufacturing, and ideal for use in aerosol (needle free) formulations, such as inhalation," says Wong. "Its greater stability at room temperature and viability ultimately could provide a more practical approach for creating and delivering a vaccine throughout the world."
Edwards, an international leader in aerosol drug and vaccine delivery, sees great promise for the advance, which he and his colleagues hope to develop in the next few years for better vaccination approaches for diseases of poverty through the international not-for-profit Medicine in Need (Mend), based in Cambridge, Paris, and Cape Town, South Africa.
"With the emergence of multidrug and extremely drug resistant TB, we hope this breakthrough is one more step to help us develop a stable vaccine to stem the tide of disease," says Bloom. "Better vaccination against TB can go a long way to addressing the current developing world health care crisis, with TB alone presently taking the lives of more than 2 million people a year. And we believe this method could also be used to improve delivery of many other vaccines."
Michael Patrick Rutter | EurekAlert!
Bacteria as pacemaker for the intestine
22.11.2017 | Christian-Albrechts-Universität zu Kiel
Researchers identify how bacterium survives in oxygen-poor environments
22.11.2017 | Columbia University
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Business and Finance
22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy