AsianScientist (Nov. 25, 2014) – Researchers at the Nanyang Technological University (NTU) have invented a biomarker that is able to both detect tumor cells as well as release anti-cancer drugs in a targeted fashion. Two studies describing the new biomarker—made from a nanophosphor particle ten thousand times smaller than a grain of sand—have been published in Small.
NTU associate professors Zhang Qichun and Joachim Loo have found a way to make the nanoparticle light up when it is activated by near-infrared light emitted by an imaging device and only if tumor cells release small signalling molecules.
Prof. Zhang said the use of near-infrared light, which is invisible to the human eye, is unique as most imaging techniques use ultraviolet light or visible light.
“Near-infrared light can penetrate three to four cm beyond the skin to deep tissue, much deeper than visible light. It also does not cause any damage to healthy cells, unlike ultraviolet or visible light,” added Prof. Zhang.
“Visible light also causes photo bleaching, which is the destruction of the fluorescence dye that reduces the amount of time doctors and scientists have to image a tissue sample. Our new biomarker has effectively eliminated such key limitations which exist in existing biological markers.”
Prof. Loo said their new biomarker can also release anti-cancer drugs by creating a layer of coating loaded with drugs on the outside of the nanoparticle. The drugs are released when the biomarker lights up in response to the near-infrared light.
“This is the first time we are able to do bio-imaging, and potentially target the delivery of drugs at the same time, as proven in small animal tests,” said Prof. Loo. “Our breakthrough will open up new doors in the various fields of nanomedicine, bioimaging and cancer therapeutics.”
The new biomarker also has other advantages. It has twice the contrast of conventional dyes and is able to emit up to three different colours of light. This means that it allows for better differentiation between healthy cells and tumour cells.
Unlike other biomarkers used for imaging such as quantum dots, the NTU biomarker has also been shown to be non-toxic, staying in the body for up to two days before it is passed out harmlessly.
Moving forward, the team from NTU’s School of Materials Science and Engineering will be looking to load multiple layers of drugs into their biomarker. If successful, doctors will be able to release two or more drugs sequentially through the biomarker. This will benefit cancer patients as there will be fewer side effects due to the small doses administered and also higher efficacy as the biomarker has the ability to accurately target tumor cells.
The articles can be found at:
Zhou et al. (2014) Rhodamine-Modified Upconversion Nanophosphors for Ratiometric Detection of Hypochlorous Acid in Aqueous Solution and Living Cells.
Zhou et al. (2014) Inorganic–Organic Hybrid Nanoprobe for NIR-Excited Imaging of Hydrogen Sulfide in Cell Cultures and Inflammation in a Mouse Model.
——
Source: Nanyang Technological University.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.
