Nov 30, 2011
Surface-biofunctionalized multicore/shell CdTe@SiO2 composite particles detect cancer cells
In bio-detection, fluorescent quantum dots (QDs) have shown remarkable advantages over conventional dyes. Yet developing suitable QD-based probes remains challenging. On the one hand, the fluorescence of QDs is very sensitive to the chemical environment, on the other hand the non-specific interactions between particle probe and biotarget are hard to avoid due to the multiple binding sites on the particle surface.
Researchers from the Institute of Chemistry, Chinese Academy of Sciences (CAS), have made important breakthroughs in achieving silica-coated CdTe QDs – CdTe@SiO2 nanoparticles – with extremely high fluorescence quantum efficiency. By manipulating the interactions among the encapsulated QDs, CdTe@SiO2 composite particles with a multi-core structure have been developed, which turn out to be an effective measure for increasing the fluorescence brightness. Building on this work, the team has recently produced surface biofunctionalized multi-core/shell CdTe@SiO2 particles for cancer cell detection.
To construct the cancer cell probes, polyethylene glycol and carboxyl groups are introduced simultaneously to the particle surface for anti-biofouling and bioligand conjugation purposes. By covalently conjugating a goat anti-human immunoglobulin G (GaHIgG) antibody to the particle surface via amidation reaction, a cancer cell probe has been developed and successfully used to detect the UM-SCC-22B human head and neck squamous cell carcinoma cell line cells via indirect fluorescent antibody assay (IFA).
In comparison with direct fluorescence antibody assay, IFA allows for significant fluorescence signal amplification in spite of the multi-step procedures and enhanced nonspecific signals. Moreover, IFA is technically meaningful for product development.
The group believes that its current investigations pave the way for simultaneously introducing anti-biofouling coating and surface reactive residues to the silica-coated CdTe QDs. Yet, the techniques are not just limited to cell labeling, they also hold promise for many other bioapplications.
Full details can be found in the journal Nanotechnology.
About the author
This work was carried out in the lab of Prof. Mingyuan Gao at the Institute of Chemistry, CAS. His main research interests include: synthesis of nanocrystals with novel properties, unusual shapes and structures; synthesis of organic/inorganic hybrid materials; biological, biomedical and environmental applications of functional nanomaterials. To date, he has published 90 peer-reviewed articles and holds 14 patents.