November 18 2017 by Juili Kelvekar
According to the Centers for Disease Control and Prevention (CDC), every year an estimated 722,000 people in the U.S. develop infections during a hospital stay, and about 75,000 die. Put another way, 1 out of every 25 inpatients in U.S. acute care hospitals acquires at least one infection.
Source: 2011 HAI Prevalence Survey; Published 2014 in New England Journal of Medicine
Many hospital acquired infections (HAIs), otherwise known as nosocomial infections, are caused by bacteria that have become resistant to the broad-spectrum antibiotics, including MRSA and VRE. Some studies have even found that three-fourths of surfaces in hospitals are infected with MRSA. Bed rails, call buttons, touch plates, chairs, door handles, light switches, grab rails, intravenous poles, soap and paper towel dispensers, dressing trolleys, and counter and table tops can all be contaminated leading to the infectious spread of bacteria.
While not all hospital-acquired infections can be prevented, the vast majority including those lurking on surfaces can. This is where nanotechnology comes into play. Here are 5 novel nanotechnologies, each with a promise to prevent hospital acquired infection.
1. Copper Coatings
In 2013 Michael Schmidt from the Medical University of South Carolina and his colleagues performed tests by coating surfaces with copper in the intensive care unit (ICU) . By active or passive uptake into cytoplasm the metallic copper ions interacted with bacterial surface proteins damaging cell the membrane; demonstrating strong antimicrobial activity. However this method is expensive and time consuming, requiring copper coating applied to full pieces of hardware.1
2. Selenium Nanoparticle Spray Cleans Surfaces
Also In 2013, Thomas Webster and former graduate students from Northeastern University developed a selenium nanoparticle spray to apply to surfaces. An animal toxicity study demonstrated it was non-hazardous to small animals, and presumably humans. Additional testing on multiple hospital surfaces found it caused a direct decrease in microbial population.2, 3
3. Nano Pits Trap Bacteria
An alternative method to bacterial cytotoxicity is trapping bacteria in pits and troughs of nanoscale dimensions etched into several synthetic materials. Joanna Verran’s group at Manchester Metropolitan University, UK showed a decrease in adhesion of bacteria and yeast strains using 300nm to micron sized pits.
4. Nanopillar Bacterial Killers
Albert Yee’s team at University of California in 2013 showed that nanopillars mimicking the texture of a cicada wing achieved the killing of gram-negative bacteria.
5. Single-Walled Carbon Nanotubes with an Antimicrobial Arsenal
Virginia Davis’s lab at Auburn University designed a sheet of antimicrobial single-walled nanotube (SWNTs) that is extremely stable at high temperature, pressure, and shear stress. The carbon backbone allowed for attachment of antimicrobial protein lysozymes which increased bacterial killing by 50% compared with non-lysozyme controls.
These nanotechnologies show that by modifying surfaces with metallic ions or nanopatterns, hospitals can kill infection causing bacteria and prevent them from forming microbial biofilms. Hopefully soon, advances in nanotechnology like these will help significantly reduce the rate of hospital acquired infections among patients and visitors.
- C.D. Salgado et al., “Copper surfaces reduce the rate of healthcare-acquired infections in the intensive care unit,” Infect Control Hosp Epidemiol, 34:479-86, 2013.
- P.A. Tran, T.J. Webster, “Antimicrobial selenium nanoparticle coatings on polymeric medical devices,” Nanotechnology, 24:155101, 2013.
- Results presented at the 2nd International Nanomedicine Conference, Boston, Massachusetts, July 25-27, 2014.