First biodegradable polymer nanoparticles that kill bacteria without destroying healthy red blood cells

13-Apr-11

Scientists at the Institute of Bioengineering and Nanotechnology (IBN) and IBM Research – Almaden have developed the first biodegradable polymer nanoparticles to combat drug-resistant superbugs, such as Methicillin-Resistant Staphylococcus aureus (MRSA). These nanoparticles can selectively kill the bacteria without destroying healthy red blood cells, and being biodegradable, have great potential to treat infectious diseases in the body, as reported in Nature Chemistry. The antimicrobial polymers can successfully inhibit the growth of antibiotic-resistant bacteria without inducing hemolysis or causing significant toxicity because only a low concentration would be required. In addition, unlike existing polymers that do not form a secondary structure before interacting with the microbial membrane, the polymers can easily self-assemble into nanoparticles when dissolved in water to eradicate the bacteria completely. Conventional antibiotics penetrate the microorganisms without damaging the bacteria structure (cell wall and membrane). Hence, the bacteria can easily develop resistance against these drugs. In comparison, antimicrobial polymers break down the bacterial cell wall and membrane based on electrostatic interaction with the bacteria to prevent drug resistance. A major side effect caused by many existing antimicrobial polymers is hemolysis, the breakdown of red blood cells, in addition to the infected cells. Most antimicrobial polymers are also non-biodegradable, which limits their in vivo applications as they cannot be naturally eliminated from the body. The starting materials of the novel polymer are inexpensive and the synthesis is simple and scalable for future clinical applications. These biodegradable nanoparticles could be topically applied to the skin or injected into the body to treat MRSA skin infections. It could also be developed into consumer products such as deodorants, table wipes and preservatives. Other potential applications include treatment for wound healing, multidrug-resistant tuberculosis and lung infections.