IBMs nanomedicine initiative – IBM Research: Overview …

Creating a hydrogel from the polymers

Through the precise tailoring of the ninja polymers, researchers were able to create macromolecules – molecular structures containing a large number of atoms – which combine water solubility, a positive charge, and biodegradability. When mixed with water and heated to normal body temperature, the polymers self-assemble, swelling into a synthetic hydrogel that is easy to manipulate.

When applied to contaminated surfaces, the hydrogel’s positive charge attracts negatively charged microbial membranes, like stars and planets being pulled into a black hole. However, unlike other antimicrobials that target the internal machinery of bacteria to try to prevent it from replicating, this hydrogel destroys the bacteria by rupturing the bacteria’s membrane, rendering it completely unable to regenerate or spread.

The hydrogel is comprised of more than 90 percent water, making it easy to handle and apply to surfaces. It also makes it potentially viable for eventual inclusion in applications like creams or injectable therapeutics for wound healing, implant and catheter coatings, skin infections or even orifice barriers. It is the first-ever to be biodegradable, biocompatible and non-toxic, potentially making it an ideal tool to combat serious health hazards facing hospital workers, visitors and patients.

The IBM scientists in the nanomedicine polymer program along with the Institute of Bioengineering and Nanotechnology have taken this research a step further and have made a nanomedicine breakthrough in which they converted common plastic materials like polyethylene terephthalate (PET) into non-toxic and biocompatible materials designed to specifically target and attack fungal infections.BCC Research reported that the treatment cost for fungal infections was $3 billion worldwide in 2010 andis expected to increase to $6 billion in 2014. In this breakthrough, the researchers identified a novel self-assembly process for broken down PET, the primary material in plastic water bottles, in which ‘super’ molecules are formed through a hydrogen bond and serve as drug carriers targeting fungal infections in the body. Demonstrating characteristics like electrostatic charge similar to polymers, the molecules are able to break through bacterial membranes and eradicate fungus, then biodegrade in the body naturally. This is important to treat eye infections associated with contact lenses, and bloodstream infections like Candida.

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IBMs nanomedicine initiative – IBM Research: Overview …

Drug-resistant Bacteria – Designing Nanoparticles For High Antibiotic Doses

Featured Article Academic Journal Main Category: MRSA / Drug Resistance Also Included In: Biology / Biochemistry Article Date: 06 May 2012 – 12:00 PDT

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The scientists have been working towards this goal by developing a nanoparticle that invades the immune system, targeting the infection sites, and subsequently release a focused antibiotic attack.

According to leading author, Aleks Radovic-Moreno, who is an MIT graduate student, this strategy would lower the side effects of some antibiotics and protect the beneficial bacteria that commonly live in the human body.

The new nanoparticles were created from a polymer capped with polyethylene glycol (PEG), which is commonly used for drug delivery due to its nontoxic properties and because it can help to transport nanoparticles through the bloodstream without being detected by the immune system. The researchers then induced the particles to specifically target bacteria. Previous attempts to target particles to bacteria by giving them a positive charge that attracts them to bacteria’s negatively charged cell walls have not been successful, given that the immune system tends to clear positively-charged nanoparticles from the body before they can encounter bacteria.

The team managed to overcome this hurdle by designing antibiotic-carrying nanoparticles, which can switch their charge depending on their environment, for instance, whilst circulating in the bloodstream, the particles’ charge is slightly negative, yet on encountering an infection site, they gain a positive charge, which allows them to bind tightly to bacteria and release their drug payload.

The switch is invoked because of the slightly acidic environment surrounding bacteria. Infection sites can be slightly more acidic compared with normal body tissue, because the bacteria that cause disease reproduce rapidly and deplete oxygen. Insufficient oxygen levels, however, trigger a change in bacterial metabolism, which prompts them to generate organic acids. The body’s immune cells try to assist – neutrophils cells start producing acids so as to to consume the bacteria.

The nanoparticles have a pH-sensitive layer that is made of long chains of the amino acid histidine just below the outer PEG layer. When the pH-level fall from 7 to 6, i.e. when it becomes more acidic, the polyhistidine molecule tends to gain protons that give the molecule a positive charge.

The nanoparticles start releasing their drug payload, which is embedded in the particle’s core, once they bind to bacteria. The researchers designed the particles to deliver vancomycin, which is used to treat drug-resistant infections, However, it is possible to modify the particles to deliver other antibiotics or combinations of drugs. With increasing acidity, many antibiotics tend to lose their efficacy. However, the team discovered that antibiotics carried by nanoparticles retained their potency better than traditional antibiotics. The current version of nanoparticles discharges its drug payload over one to two days.

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Drug-resistant Bacteria – Designing Nanoparticles For High Antibiotic Doses