Monthly Archives: February 2019

Ruthenium-based sensor detects nitric oxide

8 February 2019:

In a new publication, a responsive Ruthenium-based luminescence sensor was employed as a molecular probe for detecting nitric oxide (NO). The research suggests potential clinical utility for the measurement of soluble NO in the circulation system and possibly tissue. Lead authors of this paper are CNBP’s Dr Achini Vidanapathirana and Benjamin Pullen (both based at SAHMRI).

Journal: Scientific Reports.

Publication title:  A Novel Ruthenium-based Molecular Sensor to Detect Endothelial Nitric Oxide.

Authors: Achini K. Vidanapathirana, Benjamin J. Pullen, Run Zhang, MyNgan Duong, Jarrad M.Goyne, Xiaozhou Zhang, Claudine S. Bonder, Andrew D.Abell, Christina A. Bursill, Stephen J. Nicholls & Peter J. Psaltis.

Abstract: Nitric oxide (NO) is a key regulator of endothelial cell and vascular function. The direct measurement of NO is challenging due to its short half-life, and as such surrogate measurements are typically used to approximate its relative concentrations. Here we demonstrate that ruthenium-based [Ru(bpy)2(dabpy)]2+ is a potent sensor for NO in its irreversible, NO-bound active form, [Ru(bpy)2(T-bpy)]2+. Using spectrophotometry we established the sensor’s ability to detect and measure soluble NO in a concentration-dependent manner in cell-free media. Endothelial cells cultured with acetylcholine or hydrogen peroxide to induce endogenous NO production showed modest increases of 7.3 ± 7.1% and 36.3 ± 25.0% respectively in fluorescence signal from baseline state, while addition of exogenous NO increased their fluorescence by 5.2-fold. The changes in fluorescence signal were proportionate and comparable against conventional NO assays. Rabbit blood samples immediately exposed to [Ru(bpy)2(dabpy)]2+ displayed 8-fold higher mean fluorescence, relative to blood without sensor. Approximately 14% of the observed signal was NO/NO adduct-specific. Optimal readings were obtained when sensor was added to freshly collected blood, remaining stable during subsequent freeze-thaw cycles. Clinical studies are now required to test the utility of [Ru(bpy)2(dabpy)]2+ as a sensor to detect changes in NO from human blood samples in cardiovascular health and disease.

Gold nanomembranes with nanoholes

1 February 2019:

In a break-through in the field of nano membrane related research, CNBP alumni scientist Dr Peipei Jia and colleagues report on the development of large-area freestanding gold nanomembranes with nanohole arrays fabricated using a replication-releasing procedure. More information available below!

Journal: Materials Horizons.

Publication title:  Large-area Freestanding Gold Nanomembranes with Nanoholes.

Authors: Peipei Jia, Kamil Zuber, Qiuquan Guo, Brant C. Gibson, Jun Yang and Heike Ebendorff-Heidepriem.

Abstract: Thin metal films with nanohole arrays have opened up new opportunities in applications ranging from plasmonics to optoelectronics. However, their dependence on substrates limits not only their performance but also other application possibilities. A key challenge to overcome this limitation is to make these nanostructured films substrate-free. Here we report large-area freestanding gold nanomembranes with nanohole arrays fabricated using a replication-releasing procedure. The structures maintain spatial uniformity and pristine quality after release across the entire membrane up to 75 cm2 in area and as thin as 50 nm. The freestanding nanomembranes show significantly enhanced optical transmission and effective field extension compared to the same nanomembranes on substrates. A plasmonic coupling resonance with a 2.7 nm linewidth achieves a record figure-of-merit of 240 for refractive index sensing. The gold nanomembranes can be geometrically converted to 3D microstructures by ion-irradiation-based kirigami technique. The transformed micro-objects can be precisely controlled via geometry design and strategic cutting. Furthermore, we find the presence of nanoholes can significantly change the in-plane modulus of the gold nanomembranes. Finally, the freestanding gold nanomembranes can be transferred to non-planar substrates, enabling their future integration with advanced optical and electronic systems for emerging applications.