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LED-controlled tuning of ZnO nanowires' wettability for biosensing applications.

Bhavsar K, Ross D, Prabhu R, Pollard P - Nano Rev (2015)

Bottom Line: The investigations on spectral properties of the LED emission on ZnO nanowires' wettability have shown strong dependency on the spectral overlap of LED emission on ZnO absorption spectra.The spectral investigations have provided significant insight into the role of irradiating wavelength of light and irradiation time on the surface wettability of ZnO nanowires.This process is suitable to realize on chip based integrated sensors and has huge potential for eco-friendly biosensing and environmental sensing applications.

View Article: PubMed Central - PubMed

Affiliation: IDEAS Research Institute, Robert Gordon University, Aberdeen, UK.

ABSTRACT

Background: Wettability is an important property of solid materials which can be controlled by surface energy. Dynamic control over the surface wettability is of great importance for biosensing applications. Zinc oxide (ZnO) is a biocompatible material suitable for biosensors and microfluidic devices. Nanowires of ZnO tend to show a hydrophobic nature which decelerates the adhesion or adsorption of biomolecules on the surface and, therefore, limits their application.

Methods: Surface wettability of the ZnO nanowires can be tuned using light irradiation. However, the control over wettability using light-emitting diodes (LEDs) and the role of wavelength in controlling the wettability of ZnO nanowires are unclear. This is the first report on LED-based wettability control of nanowires, and it includes investigations on tuning the desired wettability of ZnO nanowires using LEDs as a controlling tool.

Results: The investigations on spectral properties of the LED emission on ZnO nanowires' wettability have shown strong dependency on the spectral overlap of LED emission on ZnO absorption spectra. Results indicate that LEDs offer an advanced control on dynamically tuning the wettability of ZnO nanowires.

Conclusion: The spectral investigations have provided significant insight into the role of irradiating wavelength of light and irradiation time on the surface wettability of ZnO nanowires. This process is suitable to realize on chip based integrated sensors and has huge potential for eco-friendly biosensing and environmental sensing applications.

No MeSH data available.


Related in: MedlinePlus

Measured relative contact angle change with irradiation time for different LED emissions at λp=365 nm, 385 nm,454 nm, and 519 nm. Trend line indicates the respective exponential fit to the data.
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Figure 0005: Measured relative contact angle change with irradiation time for different LED emissions at λp=365 nm, 385 nm,454 nm, and 519 nm. Trend line indicates the respective exponential fit to the data.

Mentions: To further understand the effect of wavelength, light irradiation has been carried out on the ZnO nanowires using LEDs with a peak emission wavelength λp=365 nm, 385 nm, 454 nm and 519 nm. WCA has been measured on each sample before and after the light irradiation, and referred to as WCA0 and WCA, respectively. Figure 5 shows the relative change in WCA/WCA0 measured with irradiation time for different illumination wavelengths. Rapid change in the wetting angle observed for the LED with λp=365 nm can be attributed to the higher rate of change in surface energy. A small change observed in the wetting angle under 454 nm and 519 nm illuminations can be attributed to the small fraction of light absorbed by ZnO nanowires due to the native defects. Although the spectral width of LEDs emitting at 454 nm and 519 nm is slightly higher than that of the other LEDs used in the experiment, a negligible effect has been anticipated due to very low absorption by ZnO nanowires in that range. Trend lines in the graph indicate that the change in wetting angle slows down gradually with increasing wavelength. In addition, results for the illumination wavelengths of 454 nm and 519 nm reveal that there was no clear hydrophobic-to-hydrophilic transition observed within 30 min of irradiation. These results indicate that the wettability of the ZnO nanowires can be controlled by tuning the wavelength of irradiating light.


LED-controlled tuning of ZnO nanowires' wettability for biosensing applications.

Bhavsar K, Ross D, Prabhu R, Pollard P - Nano Rev (2015)

Measured relative contact angle change with irradiation time for different LED emissions at λp=365 nm, 385 nm,454 nm, and 519 nm. Trend line indicates the respective exponential fit to the data.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390563&req=5

Figure 0005: Measured relative contact angle change with irradiation time for different LED emissions at λp=365 nm, 385 nm,454 nm, and 519 nm. Trend line indicates the respective exponential fit to the data.
Mentions: To further understand the effect of wavelength, light irradiation has been carried out on the ZnO nanowires using LEDs with a peak emission wavelength λp=365 nm, 385 nm, 454 nm and 519 nm. WCA has been measured on each sample before and after the light irradiation, and referred to as WCA0 and WCA, respectively. Figure 5 shows the relative change in WCA/WCA0 measured with irradiation time for different illumination wavelengths. Rapid change in the wetting angle observed for the LED with λp=365 nm can be attributed to the higher rate of change in surface energy. A small change observed in the wetting angle under 454 nm and 519 nm illuminations can be attributed to the small fraction of light absorbed by ZnO nanowires due to the native defects. Although the spectral width of LEDs emitting at 454 nm and 519 nm is slightly higher than that of the other LEDs used in the experiment, a negligible effect has been anticipated due to very low absorption by ZnO nanowires in that range. Trend lines in the graph indicate that the change in wetting angle slows down gradually with increasing wavelength. In addition, results for the illumination wavelengths of 454 nm and 519 nm reveal that there was no clear hydrophobic-to-hydrophilic transition observed within 30 min of irradiation. These results indicate that the wettability of the ZnO nanowires can be controlled by tuning the wavelength of irradiating light.

Bottom Line: The investigations on spectral properties of the LED emission on ZnO nanowires' wettability have shown strong dependency on the spectral overlap of LED emission on ZnO absorption spectra.The spectral investigations have provided significant insight into the role of irradiating wavelength of light and irradiation time on the surface wettability of ZnO nanowires.This process is suitable to realize on chip based integrated sensors and has huge potential for eco-friendly biosensing and environmental sensing applications.

View Article: PubMed Central - PubMed

Affiliation: IDEAS Research Institute, Robert Gordon University, Aberdeen, UK.

ABSTRACT

Background: Wettability is an important property of solid materials which can be controlled by surface energy. Dynamic control over the surface wettability is of great importance for biosensing applications. Zinc oxide (ZnO) is a biocompatible material suitable for biosensors and microfluidic devices. Nanowires of ZnO tend to show a hydrophobic nature which decelerates the adhesion or adsorption of biomolecules on the surface and, therefore, limits their application.

Methods: Surface wettability of the ZnO nanowires can be tuned using light irradiation. However, the control over wettability using light-emitting diodes (LEDs) and the role of wavelength in controlling the wettability of ZnO nanowires are unclear. This is the first report on LED-based wettability control of nanowires, and it includes investigations on tuning the desired wettability of ZnO nanowires using LEDs as a controlling tool.

Results: The investigations on spectral properties of the LED emission on ZnO nanowires' wettability have shown strong dependency on the spectral overlap of LED emission on ZnO absorption spectra. Results indicate that LEDs offer an advanced control on dynamically tuning the wettability of ZnO nanowires.

Conclusion: The spectral investigations have provided significant insight into the role of irradiating wavelength of light and irradiation time on the surface wettability of ZnO nanowires. This process is suitable to realize on chip based integrated sensors and has huge potential for eco-friendly biosensing and environmental sensing applications.

No MeSH data available.


Related in: MedlinePlus