Featured Research

from universities, journals, and other organizations

Silica Smart Bombs Deliver Knock-out To Bacteria

Date:
February 26, 2008
Source:
University of North Carolina at Chapel Hill
Summary:
Bacteria mutate for a living, evading antibiotic drugs while killing tens of thousands of people in the United States each year. But as concern about drug-resistant bacteria grows, one novel approach seeks to thwart the bug without a drug by taking a cue from nature.

Mark Schoenfisch and his lab of analytical chemists at UNC have created nano-scale scaffolds made of silica and loaded with nitric oxide (NO) -- an important molecule in mammals that plays a role in regulating blood pressure, neurotransmission and fighting bacterial infections, among other vital functions.
Credit: Image courtesy of University of North Carolina at Chapel Hill

Bacteria mutate for a living, evading antibiotic drugs while killing tens of thousands of people in the United States each year. But as concern about drug-resistant bacteria grows, one novel approach under way at the University of North Carolina at Chapel Hill seeks to thwart the bug without a drug by taking a cue from nature.

Mark Schoenfisch and his lab of analytical chemists at UNC have created nano-scale scaffolds made of silica and loaded with nitric oxide (NO) -- an important molecule in mammals that plays a role in regulating blood pressure, neurotransmission and fighting bacterial infections, among other vital functions.

"There was evidence that nitric oxide kills bacteria, but the difficult part involved storing it in a manner such that it could be delivered to bacterial cells," said Evan Hetrick, a doctoral student in Schoenfisch's lab and lead author on a paper in the February issue of the American Chemical Society's journal ACS Nano.

While the body constantly produces NO, and can ramp up its production to fight infection, sometimes it can't produce enough to mount a sufficient defense. Previous research using small molecules to deliver NO hit roadblocks -- controlling the release of the compound was difficult and the molecules were potentially toxic to healthy cells in the body.

"With silica scaffolds, nitric oxide stores easily and we could very carefully control the release," said Schoenfisch, an associate professor of chemistry in UNC's College of Arts and Sciences.

Schoenfisch, Hetrick and their colleagues tested their silica scaffolds head-to-head with small molecules against the bacteria Pseudomonas aeruginosa, which is commonly found in burn and other wound infections.

NO delivered by both methods completely killed the bacteria. But the silica nanoparticles delivered the NO right to the bacteria's doorstep. In contrast, the small molecules released NO indiscriminately, and the concentration of NO is lost as it makes its way toward bacterial cells.

"With the silica particles, more NO actually reached the inside of the cells, enhancing the efficacy of the nanoparticles compared to the small molecule. So, the overall amount of NO needed to kill bacteria is much less with silica nanoparticles," Schoenfisch said. "And, with small molecules, you're left with potentially toxic byproducts," Schoenfisch said. Using mouse cells, they proved that the silica nanoparticles weren't toxic to healthy cells, but the small molecules were.

Schoenfisch has a history of success with NO-releasing materials. His lab has successfully created a variety of coatings for different biomedical applications. Such materials hold promise as anti-infective coatings and as methods to improve the body's integration of biological implants -- such as hip or knee joints -- and implanted sensors that relay various biological measures, such as blood glucose or oxygen concentrations.

The amount and rate of NO release are easily modified and controlled by using these different silica nanoparticles. "Release rates are a function of the precursors used to make the nanoparticles," Schoenfisch said. "It depends entirely on how we build the silica structures."

Future research will include studying additional bacterial strains, active targeting, preferential uptake and biodistribution studies.


Story Source:

The above story is based on materials provided by University of North Carolina at Chapel Hill. Note: Materials may be edited for content and length.


Cite This Page:

University of North Carolina at Chapel Hill. "Silica Smart Bombs Deliver Knock-out To Bacteria." ScienceDaily. ScienceDaily, 26 February 2008. <www.sciencedaily.com/releases/2008/02/080225213452.htm>.
University of North Carolina at Chapel Hill. (2008, February 26). Silica Smart Bombs Deliver Knock-out To Bacteria. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2008/02/080225213452.htm
University of North Carolina at Chapel Hill. "Silica Smart Bombs Deliver Knock-out To Bacteria." ScienceDaily. www.sciencedaily.com/releases/2008/02/080225213452.htm (accessed September 20, 2014).

Share This



More Plants & Animals News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins