Limits...
Optimization and application of reflective LSPR optical fiber biosensors based on silver nanoparticles.

Chen J, Shi S, Su R, Qi W, Huang R, Wang M, Wang L, He Z - Sensors (Basel) (2015)

Bottom Line: Moreover, the sensor was further modified with antigen to act as a biosensor.Distinctive wavelength shifts were found after each surface modification step.In addition, the reflective LSPR optical fiber sensor has high reproducibility and stability.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China. cjpjm@126.com.

ABSTRACT
In this study, we developed a reflective localized surface plasmon resonance (LSPR) optical fiber sensor, based on silver nanoparticles (Ag NPs). To enhance the sensitivity of the LSPR optical sensor, two key parameters were optimized, the length of the sensing area and the coating time of the Ag NPs. A sensing length of 1.5 cm and a 1-h coating time proved to be suitable conditions to produce highly sensitive sensors for biosensing. The optimized sensor has a high refractive index sensitivity of 387 nm/RIU, which is much higher than that of other reported individual silver nanoparticles in solutions. Moreover, the sensor was further modified with antigen to act as a biosensor. Distinctive wavelength shifts were found after each surface modification step. In addition, the reflective LSPR optical fiber sensor has high reproducibility and stability.

No MeSH data available.


Related in: MedlinePlus

Refractive index sensitivities of the Ag NP-based sensors with different coating time of 0.5 h, 1 h, and 3 h. (A) illustrates the wavelength shifts comparison of the Ag NP-based sensors with three different coating times; (B) illustrates the optical intensity shifts comparison of the Ag NP-based sensors with three different coating time.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4507690&req=5

sensors-15-12205-f005: Refractive index sensitivities of the Ag NP-based sensors with different coating time of 0.5 h, 1 h, and 3 h. (A) illustrates the wavelength shifts comparison of the Ag NP-based sensors with three different coating times; (B) illustrates the optical intensity shifts comparison of the Ag NP-based sensors with three different coating time.

Mentions: A similar experiment was carried out to investigate the influence of the Ag NP coating time on the sensitivity of the sensor probe. We produced a series of sensor probes with different coating times of 0.5 h, 1 h and 3 h. The results obtained are shown in Figure 5. As observed, with an increase in coating time, the sensitivity initially increased from 173 nm/RIU to 461 nm/RIU (Figure 5A). However, as the coating time further increased, reaching 3 h, the sensitivity decreased to 355 nm/RIU and a new plasmon resonance band was observed in the higher wavelength region from 600 nm to 800 nm in the reflectivity spectrum, as shown in Figure S2 (Supplementary materials). This observation appears to be different from a finding reported previously [40]. As predicted, there was an increase in the refractive index sensitivity relative to the decrease in the particle pair partner’s distances. As for this contradiction, we believed that the reason may be the aggregation of the absorbed nanoparticles. The appearance of a new plasmon resonance band further proves our assumption, which is inconsistent with that of other reported literature we mentioned above [35]. Hence, the total 1 h time was sufficient for the coating process using our approach. With longer coating times, a higher level of aggregation of the nanoparticles may occur, making it difficult to obtain a sensitive optical sensor probe. Moreover, we also studied the relationship between the optical intensity shift and the coating times; the results are illustrated in Figure 5B. With an increase in the coating time, the reflectivity decreased, and the sensitivity also decreased from 195%/RIU to 57%/RIU. The aggregation of the Ag NPs did not impart changes to the optical intensity.


Optimization and application of reflective LSPR optical fiber biosensors based on silver nanoparticles.

Chen J, Shi S, Su R, Qi W, Huang R, Wang M, Wang L, He Z - Sensors (Basel) (2015)

Refractive index sensitivities of the Ag NP-based sensors with different coating time of 0.5 h, 1 h, and 3 h. (A) illustrates the wavelength shifts comparison of the Ag NP-based sensors with three different coating times; (B) illustrates the optical intensity shifts comparison of the Ag NP-based sensors with three different coating time.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507690&req=5

sensors-15-12205-f005: Refractive index sensitivities of the Ag NP-based sensors with different coating time of 0.5 h, 1 h, and 3 h. (A) illustrates the wavelength shifts comparison of the Ag NP-based sensors with three different coating times; (B) illustrates the optical intensity shifts comparison of the Ag NP-based sensors with three different coating time.
Mentions: A similar experiment was carried out to investigate the influence of the Ag NP coating time on the sensitivity of the sensor probe. We produced a series of sensor probes with different coating times of 0.5 h, 1 h and 3 h. The results obtained are shown in Figure 5. As observed, with an increase in coating time, the sensitivity initially increased from 173 nm/RIU to 461 nm/RIU (Figure 5A). However, as the coating time further increased, reaching 3 h, the sensitivity decreased to 355 nm/RIU and a new plasmon resonance band was observed in the higher wavelength region from 600 nm to 800 nm in the reflectivity spectrum, as shown in Figure S2 (Supplementary materials). This observation appears to be different from a finding reported previously [40]. As predicted, there was an increase in the refractive index sensitivity relative to the decrease in the particle pair partner’s distances. As for this contradiction, we believed that the reason may be the aggregation of the absorbed nanoparticles. The appearance of a new plasmon resonance band further proves our assumption, which is inconsistent with that of other reported literature we mentioned above [35]. Hence, the total 1 h time was sufficient for the coating process using our approach. With longer coating times, a higher level of aggregation of the nanoparticles may occur, making it difficult to obtain a sensitive optical sensor probe. Moreover, we also studied the relationship between the optical intensity shift and the coating times; the results are illustrated in Figure 5B. With an increase in the coating time, the reflectivity decreased, and the sensitivity also decreased from 195%/RIU to 57%/RIU. The aggregation of the Ag NPs did not impart changes to the optical intensity.

Bottom Line: Moreover, the sensor was further modified with antigen to act as a biosensor.Distinctive wavelength shifts were found after each surface modification step.In addition, the reflective LSPR optical fiber sensor has high reproducibility and stability.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China. cjpjm@126.com.

ABSTRACT
In this study, we developed a reflective localized surface plasmon resonance (LSPR) optical fiber sensor, based on silver nanoparticles (Ag NPs). To enhance the sensitivity of the LSPR optical sensor, two key parameters were optimized, the length of the sensing area and the coating time of the Ag NPs. A sensing length of 1.5 cm and a 1-h coating time proved to be suitable conditions to produce highly sensitive sensors for biosensing. The optimized sensor has a high refractive index sensitivity of 387 nm/RIU, which is much higher than that of other reported individual silver nanoparticles in solutions. Moreover, the sensor was further modified with antigen to act as a biosensor. Distinctive wavelength shifts were found after each surface modification step. In addition, the reflective LSPR optical fiber sensor has high reproducibility and stability.

No MeSH data available.


Related in: MedlinePlus