Chengchen Duan*, Run Zhang, Zhiping Xu

 

Australian Institute for Bioengineering and Nanotechnology (AIBN)
The University of Queensland
Brisbane, Queensland, Australia

 

Gasotransmitters, including hydrogen sulfide (H2S), nitric oxide (NO), carbon monoxide (CO), and sulphur dioxide (SO2) have long been recognised as the key biomarkers for early diagnostic of cancer and cardiovascular disease. Since these biomolecules are extremely active inside the body, quantitative monitoring these molecules in complicated biological environment remains a challenge. In our previous work, a ruthenium complex, [Ru(bpy)2(bpy-DPA)Cu]4+ has successfully developed for highly sensitive and selective detection of H2S.1  However, detection of H2S in biological samples, such as serum has not been achieved due to the effects from other biomolecules and the biocompatibility of the probe. To address this issue, we designed and prepared a mesoporous silica nanoparticles (MSN)-based ratiometric luminescent nanoprobe for quantitative monitoring of H2S in live organism in this contribution. 
Fluorescein Isothiocyanate (FITC)-doped MSN was initially prepared, followed by the loading of positive charged responsive ruthenium(II) complexes in the nanopores of MSN. Luminescence spectra of the prepared nanoprobe clearly showed emission of at 520 nm and 600 nm, which can be attributed to the emission of FITC and the metal-to-ligand electron transfer (MLCT)-based luminescence of ruthenium(II) complexes. In the presence of H2S, the emission at 600 nm was significantly increased. The enhancement of the emission at I600/I520 exhibited H2S concentration dependent, with a good linearity for ratiometric quantification of H2S. The activatable nanoprobe prepared in this work showed low cytotoxicity, can be potential used for monitoring of H2S in biological systems. The emission of FITC-doped MSN is pH dependent. Therefore, discrimination of the H2S generation in normal tissue and cancer lesion, where the pH is lower, and monitoring the evolution of H2S in tumour tissue during therapy are expected in the future studies. 

References 
1 Zhang, Run, et al. "Development of a heterobimetallic Ru (II)–Cu (II) complex for highly selective and sensitive luminescence sensing of sulfide anions." Analytica chimica acta 691.1 (2011): 83-88.
Biographic Details
Name: Chengchen Duan
Title: Mr.
Affiliation, Country: AIBN, Australia
Phone: +61 432096497  E-mail: c.duan@uq.net.au
Research interests: Biosensor, Cancer early diagnosis, Silica nanoparticles