Jul 20, 2011
Multicolour biomarkers formed by encapsulating organic dyes in nano matrix
Organic ﬂuorophores are widely used as fluorescent markers, but they have some inherent drawbacks, such as poor resistance to photobleaching, low quantum yields and optical properties that are vulnerable to the surrounding environment. To tackle these issues, researchers at the State Key Laboratory of Supramolecular Structure and Materials (SKLSSM), Jilin University, China, have developed a novel highly stable, multicolour biomarker by encapsulating organic dyes into a nano polymer matrix.
Charged organic dyes were either adsorbed on or embedded in PMMA nanoparticles (NPs), whose charges were adjusted by choosing different initiators. The combination of the dye with the PMMA NPs enhances its optical properties, for example, quantum yields and anti-photobleaching. Also, the photostability of these fluorescent dyes was seen to increase when incorporated into PMMA NPs.
Adjustable charge and various combination strategies widen the number of dye options, which makes it possible to synthesize multicoloured NPs. These multicoloured dye@PMMA nanocomposites were found to be excellent nanolabels for bioimaging of blood cancer cells. The culturing of the blood cancer cells was carried out at the Institute of Frontier Medical Science (IFMS), Jilin University, China, with the co-operation of Prof. Fei Sun's group.
Quantum dots and nanoclusters
Besides organic dyes, other ﬂuorophores such as the semiconductor quantum dot and metal (Ag/Au) nanoclusters can be embedded in polymer NPs, which can reduce the toxicity of quantum dots and enhance the stability of metal nanoclusters. Accordingly, the combination of quantum dots and Ag nanoclusters will be investigated as a continuation of this work.
Researchers at the SKLSSM, Jilin University, strive to improve the optical properties of fluorescent material and Raman active material. Besides using polymer matrices, the optical properties can be improved by various plasmonic materials. The metal enhanced fluorescence (MEF) effect has been applied to enhance the quantum yield of fluorescence dyes. Surface enhanced Raman scattering (SERS) spectra is another research field for the team.
Further details can be found in the journal Nanotechnology.
About the author
Prof. Weiqing Xu is a group leader at the State Key Laboratory of Supramolecular Structure and Materials (SKLSSM), Jilin University, China. His interests include the preparation and spectral characterization of plasmonic materials and surface plasmon field-enhanced spectroscopy. Xumei Wang is a PhD student in the Weiqing Xu group at SKLSSM. Her research focuses on the synthesis of novel fluorescence biomarkers.