Research creates nanoparticles perfectly formed to tackle cancer

6 June 2011

Researchers from the University of Hull have discovered a way to load up nanoparticles with large numbers of light-sensitive molecules to create a more effective form of photodynamic therapy (PDT) for treating cancer.

Dr Ross Boyle

Photodynamic therapy uses molecules which, when irradiated with light, cause irreparable damage to cells by creating toxic forms of oxygen, called reactive oxygen species.

< Dr Ross Boyle

Most PDT works with individual light-sensitive molecules – but the new nanoparticles could each carry hundreds of molecules to a cancer site.

A number of different light-sensitive molecules – collectively known as photosensitisers – are used in PDT and each absorbs a very specific part of the light spectrum. The research team – from the University of Hull’s Department of Chemistry - placed one kind of photosensitiser inside each nanoparticle and another on the outside, which meant that far more reactive oxygen species could be created from the same amount of light. The findings are published in the current issue of Molecular Pharmaceutics.

The nanoparticles have also been designed to be the perfect size and shape to penetrate easily into the tumour, as lead researcher, Dr Ross Boyle, explains.

“Small cancer tumours get nutrients and oxygen by diffusion, but once tumours reach a certain size, they need to create blood vessels to continue growing, “ he says. “These new blood vessels, or neovasculature, are ‘leaky’ because the vessel walls are not as tightly knit as normal blood vessels. Our nanoparticles have been designed so the pressure in the blood vessels will push them through the space between the cells to get into the tumour tissue.”

The nanoparticles are made from a material that limits the leaching of its contents while in the bloodstream, but when activated with light, at the tumour, the toxic reactive oxygen species can diffuse freely out of the particles; meaning that damage is confined to the area of the cancer.

The researchers tested the nanoparticles on colon cancer cells, and while they were able to penetrate the cells, they also found that the nanoparticles could still be effective when near – rather than inside – the cancer cells.

“Some types of cancer cell are able to expel conventional drugs, >so if we can make this kind of therapy work simply by getting the nanoparticles between the cancer cells, rather than inside them, it could be very beneficial,” says Dr Boyle.

Page last updated by Stacey Knaggs on 10/04/2015

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Notes to Editors

The paper, 'Polyacrylamide nanoparticles as a delivery system in photodynamic therapy' is published in Molecular Pharmaceutics Vol 8; Issue 3. Ref: mp-2011-00023y.R1

Dr Ross Boyle is a Reader in the Department of Chemistry, University of Hull. He specialises in photodynamic therapy, particularly its applications to cancer treatments.

Health research at the University of Hull
Health-related research at the University of Hull ranges from biology and biochemistry to sports science, psychology and medicine.

The University heads major UK and EU clinical trials into heart disease, dementia care, obesity and nutrition and is a recognised centre for research into head and neck cancers, medical imaging, respiratory diseases and remote monitoring of health conditions (telehealth).

Health research at the University of Hull is highly translational, with strong links between fundamental scientists and clinicians ensuring maximum impact on treatment and practice.

The University has a joint medical school with the University of York – Hull York Medical School (HYMS) – which works closely with regional NHS trusts and trains 130 new doctors each year.