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The Conversation - Fighting super bugs with nanotechnology and light

DCN Corp® - A Quantum dot (QD) via a High-resolution Transmission Electron Micrograph (HR-TEM) of cadmium telluride nanoparticles (CdTe NPs). Please Note the scale bar in the lower right is 2 nanometers (nm) long, or two millionths of a millimeter (mm). Credit - Nagpal Group in association with University of Colorado (UoC), USAA novel tool is emerging in the field of combating antibiotic-resistant bacterial diseases. Globally efforts in the field to limit the overuse and abuse of antibiotic drugs is ongoing, with nanomedicine seen as providing additional ways to attack the super-bugs

As historically known nanoparticles (NP) are a million times smaller than a millimeter (mm), extremely stable, efficient in a delivery system and readily implementable into cells.

Interestingly in recent work via a group of researchers at the University of Colorado (UoC), USA, they have used a derivative of NPs known as nanoscale Quantum dots (QD), which can kill drug-resistant super-bugs without harming the surrounding healthy tissue. QDs are, also, typically described as nano-scale semiconductor particles, which can have their light-absorption properties almost customised.

The research focused on introducing QDs into the human body. The QDs do nothing until they are activated by having a light source shined on to them. Any visible light source can be used for this procedure - including a lamp, room light, torch, etc. The initial phase of the research has centred around topical infections on the skin. In other words, the deeper inside the body, then consequently the requirement is for a brighter light and a greater density of NPs.

When the QDs are activated by light they start generating electrons that attach themselves to dissolved Oxygen (O2) in the cells, thus, creating radical ions. The ions interrupt biochemical reactions which the cells rely upon for communication and basic life functions. In this procedure, the research team have sought to target and kill very specific bacterial cells that cause illnesses.

The super-bug threat

Antibiotics are not just used to treat active bacterial infections, they are also routinely provided to patients when undergoing surgery as well as patients, unfortunately, effected in their immune systems from fatal diseases, such as HIV, cancer, etc.

However, bacteria or more so "super-bugs" can be resistant to more than one antibiotic drug, with worryingly current infection rates at more then 2 million Americans per year, and of those at least 23,000 unfortunately pass away. Also, globally bacterial infections can kill more than 700,000 people per year.

Scarily projections from the UK governmental research councils suggest that if continued to be unchecked - super-bugs could potentially kill more than 10 million people per year by 2050. Such a projection would by all known metrics outpace all other major causes of death rates - including diabetes, cancer, diarrhoea and road accidents. If all such projections came true then the economic cost is estimated to be at $100 trillion by 2050.

Focusing on a target

There are alternative nano-scale medicines for combating infectious bacteria, which when exposed to light, they heat-up, and end-up killing all the cells around the infected area and not just that of the disease-causing ones. Such light exposure, therefore, requires special tools, such as proteins and/or antibodies that selectively stick to desired cell types, to ensure delivery is completed to very specific locations. Consequently this requires the ability to accurately identify target cells.

The procedure proposed by the UoC team is claimed to be a marked improvement, because it enables more specific targeting of the cells to be treated. QDs with differing sizes and electrical properties can help create different disruptive ions, which allow doctors to choose disruptors to kill invading bacteria without harming nearby healthy tissue. The activated QDs upset the balance of the chemical processes, typically known as a "reduction-oxidation" (redox) reaction, in disease-causing bacteria in order to kill them.

Employing the procedure proposed via a standard light bulb, the research team were able to eliminate a broad range of antibiotic-resistant bacteria. The bacteria was provided in the form of actual clinical samples via the UoC School of Medicine, which included some of the most dangerous drug-resistant infections known, such as methicillin-resistant Staphylococcus aureus, extended-spectrum B-lactamase-producing Klebsiella pneumoniae and Salmonella typhimurium, multi-drug resistant Escherichia coli and carbapenem-resistant Escherichia coli.

The research team were able to make their NPs with different reaction rates to the light source, including having no response or even improving cellular reproduction. As explained, above, increasing the growth of super-bugs is not desirable, but the discovery as described may encourage the growth of useful bacteria, such as bio-reactors. Original article available here

Please Note the results to the research have been published in Nature Materials 2016.

As with other USA studies, the research, above, clearly highlights the great potential of NPs/QDs and its interesting interaction with a light source. As an alternative means of implementing via a non-invasive process - DCN Corp strongly believes it can compete. Going forward, if you and/or your colleagues are interested in making DCN Corp's alternative process reality - please ensure to contact the company as soon as practicably possible.