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Real-time selective visual monitoring of Hg(2+) detection at ppt level: An approach to lighting electrospun nanofibers using gold nanoclusters.

Senthamizhan A, Celebioglu A, Uyar T - Sci Rep (2015)

Bottom Line: The resultant AuNC*PCL-NF exhibiting remarkable stability more than four months at ambient environment and facilitates increased accessibility to active sites resulting in improved sensing performance with rapid response time.The underlying mechanism is found to be due to the formation of Au-Hg amalgam, which was further investigated with XPS, TEM and elemental mapping studies.In short, our findings may lead to develop very efficient fluorescent-based nanofibrous mercury sensor, keeping in view of its stability, simplicity, reproducibility, and low cost.

View Article: PubMed Central - PubMed

Affiliation: UNAM-National Nanotechnology Research Center, Bilkent University, Ankara, 06800, Turkey.

ABSTRACT
In this work, fluorescent gold nanocluster (AuNC) decorated polycaprolactone (PCL) nanofibers (AuNC*PCL-NF) for real time visual monitoring of Hg(2+) detection at ppt level in water is demonstrated. The resultant AuNC*PCL-NF exhibiting remarkable stability more than four months at ambient environment and facilitates increased accessibility to active sites resulting in improved sensing performance with rapid response time. The fluorescence changes of AuNC*PCL-NF and their corresponding time dependent spectra, upon introduction of Hg(2+), led to the visual identification of the sensor performance. It is observed that the effective removal of excess ligand (bovine serum albumin (BSA) greatly enhances the surface exposure of AuNC and therefore their selective sensing performance is achieved over competent metal ions such as Cu(2+), Ni(2+), Mn(2+), Zn(2+), Cd(2+), and Pb(2+) present in the water. An exceptional interaction is observed between AuNC and Hg(2+), wherein the absence of excess interrupting ligand makes AuNC more selective towards Hg(2+). The underlying mechanism is found to be due to the formation of Au-Hg amalgam, which was further investigated with XPS, TEM and elemental mapping studies. In short, our findings may lead to develop very efficient fluorescent-based nanofibrous mercury sensor, keeping in view of its stability, simplicity, reproducibility, and low cost.

No MeSH data available.


Related in: MedlinePlus

Real time visual monitoring of Hg2+ detection. Time dependent CLSM images and their corresponding spectra of AuNC*PCL-SNF upon addition of 100 ppt Hg2+. [Note: An immediate disappearance of fluorescence has been observed when the Hg2+ solution is placed directly on a SNF. To overcome this, we have performed real time monitoring by placing the Hg2+ solution near the surface of the SNF and frequently capture the image every second. The solution slowly contacted near the surface of NF, following which decreased fluorescence intensity has been observed resulting in complete disappearance after 10 seconds].
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f6: Real time visual monitoring of Hg2+ detection. Time dependent CLSM images and their corresponding spectra of AuNC*PCL-SNF upon addition of 100 ppt Hg2+. [Note: An immediate disappearance of fluorescence has been observed when the Hg2+ solution is placed directly on a SNF. To overcome this, we have performed real time monitoring by placing the Hg2+ solution near the surface of the SNF and frequently capture the image every second. The solution slowly contacted near the surface of NF, following which decreased fluorescence intensity has been observed resulting in complete disappearance after 10 seconds].

Mentions: Going a step ahead, we have also performed the real time detection of Hg2+ since response time is a key factor in evaluating the practical application of a sensor. Firstly, making it certain that the observed response has been due to specific binding with mercury and not with water, we have evaluated supplementary control experiments with water. As expected, no change in the fluorescence intensity has been observed when treated with water (3 μL, see Fig. S15) and even higher volume (6 μL, see Fig. S16). As shown in Fig. 5, after 2 μL of 1 ppb Hg2+ introduced (at t =1s), a gradual decrease of fluorescence intensity has been noticed corresponding to an increasing time. The majority of intensity decreased within 30 seconds suggesting a faster response time with low amount of analyte solution. More interestingly, an immediate disappearance of fluorescence has been observed when the Hg2+ solution is directly placed on a SNF. To overcome this, we have performed real time monitoring by placing the Hg2+ solution near the surface of the SNF and frequently capture the image every second. The solution slowly contacted near the surface of SNF, following which decreased fluorescence intensity has been observed resulting in complete disappearance after 10 seconds. The conspicuous changes in the spectrum profile as well their images have been recorded and presented in Fig. 6. As compared with bulk NF ensembles, the SNF have reported faster response time. In order to visualize the effect of Hg2+ on the morphology of AuNC*PCL-NF in real time, 1 ppm Hg2+ had been exposed on their surface with the DIC images captured simultaneously (see Fig. S17).


Real-time selective visual monitoring of Hg(2+) detection at ppt level: An approach to lighting electrospun nanofibers using gold nanoclusters.

Senthamizhan A, Celebioglu A, Uyar T - Sci Rep (2015)

Real time visual monitoring of Hg2+ detection. Time dependent CLSM images and their corresponding spectra of AuNC*PCL-SNF upon addition of 100 ppt Hg2+. [Note: An immediate disappearance of fluorescence has been observed when the Hg2+ solution is placed directly on a SNF. To overcome this, we have performed real time monitoring by placing the Hg2+ solution near the surface of the SNF and frequently capture the image every second. The solution slowly contacted near the surface of NF, following which decreased fluorescence intensity has been observed resulting in complete disappearance after 10 seconds].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4446990&req=5

f6: Real time visual monitoring of Hg2+ detection. Time dependent CLSM images and their corresponding spectra of AuNC*PCL-SNF upon addition of 100 ppt Hg2+. [Note: An immediate disappearance of fluorescence has been observed when the Hg2+ solution is placed directly on a SNF. To overcome this, we have performed real time monitoring by placing the Hg2+ solution near the surface of the SNF and frequently capture the image every second. The solution slowly contacted near the surface of NF, following which decreased fluorescence intensity has been observed resulting in complete disappearance after 10 seconds].
Mentions: Going a step ahead, we have also performed the real time detection of Hg2+ since response time is a key factor in evaluating the practical application of a sensor. Firstly, making it certain that the observed response has been due to specific binding with mercury and not with water, we have evaluated supplementary control experiments with water. As expected, no change in the fluorescence intensity has been observed when treated with water (3 μL, see Fig. S15) and even higher volume (6 μL, see Fig. S16). As shown in Fig. 5, after 2 μL of 1 ppb Hg2+ introduced (at t =1s), a gradual decrease of fluorescence intensity has been noticed corresponding to an increasing time. The majority of intensity decreased within 30 seconds suggesting a faster response time with low amount of analyte solution. More interestingly, an immediate disappearance of fluorescence has been observed when the Hg2+ solution is directly placed on a SNF. To overcome this, we have performed real time monitoring by placing the Hg2+ solution near the surface of the SNF and frequently capture the image every second. The solution slowly contacted near the surface of SNF, following which decreased fluorescence intensity has been observed resulting in complete disappearance after 10 seconds. The conspicuous changes in the spectrum profile as well their images have been recorded and presented in Fig. 6. As compared with bulk NF ensembles, the SNF have reported faster response time. In order to visualize the effect of Hg2+ on the morphology of AuNC*PCL-NF in real time, 1 ppm Hg2+ had been exposed on their surface with the DIC images captured simultaneously (see Fig. S17).

Bottom Line: The resultant AuNC*PCL-NF exhibiting remarkable stability more than four months at ambient environment and facilitates increased accessibility to active sites resulting in improved sensing performance with rapid response time.The underlying mechanism is found to be due to the formation of Au-Hg amalgam, which was further investigated with XPS, TEM and elemental mapping studies.In short, our findings may lead to develop very efficient fluorescent-based nanofibrous mercury sensor, keeping in view of its stability, simplicity, reproducibility, and low cost.

View Article: PubMed Central - PubMed

Affiliation: UNAM-National Nanotechnology Research Center, Bilkent University, Ankara, 06800, Turkey.

ABSTRACT
In this work, fluorescent gold nanocluster (AuNC) decorated polycaprolactone (PCL) nanofibers (AuNC*PCL-NF) for real time visual monitoring of Hg(2+) detection at ppt level in water is demonstrated. The resultant AuNC*PCL-NF exhibiting remarkable stability more than four months at ambient environment and facilitates increased accessibility to active sites resulting in improved sensing performance with rapid response time. The fluorescence changes of AuNC*PCL-NF and their corresponding time dependent spectra, upon introduction of Hg(2+), led to the visual identification of the sensor performance. It is observed that the effective removal of excess ligand (bovine serum albumin (BSA) greatly enhances the surface exposure of AuNC and therefore their selective sensing performance is achieved over competent metal ions such as Cu(2+), Ni(2+), Mn(2+), Zn(2+), Cd(2+), and Pb(2+) present in the water. An exceptional interaction is observed between AuNC and Hg(2+), wherein the absence of excess interrupting ligand makes AuNC more selective towards Hg(2+). The underlying mechanism is found to be due to the formation of Au-Hg amalgam, which was further investigated with XPS, TEM and elemental mapping studies. In short, our findings may lead to develop very efficient fluorescent-based nanofibrous mercury sensor, keeping in view of its stability, simplicity, reproducibility, and low cost.

No MeSH data available.


Related in: MedlinePlus