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Optical birefringence of liquid crystals for label-free optical biosensing diagnosis.

Nguyen TT, Han GR, Jang CH, Ju H - Int J Nanomedicine (2015)

Bottom Line: We also provide estimation of the zenithal orientation of LCs near the gold surface of the hybrid interfaces, based on the phase retardation determined.The estimated limit of bovine serum albumin detection is approximately 2.1 μM.This optical technique with LCs can serve an optical platform for label-free quantitative diagnosis of proteins in a real time manner.

View Article: PubMed Central - PubMed

Affiliation: Department of Bionano Technology, Gachon University, Seongnam-City, South Korea.

ABSTRACT

Purpose: We present a polarization-sensitive optical detection platform for label-free quantitative optical biosensing diagnosis using liquid crystals (LCs). This is capable of determining quantitatively the optical birefringence of optical cells containing LCs, whose orientation depends on the immobilized biomolecules.

Patients and methods: This technique uses a polarization-dependent double-port detection without any polarizer at a single wavelength and removes the need of aligning optical cells of LCs in the azimuthal direction, with respect to the light path through the optical cell. Thus, this technique enables a stand-alone detection in a relatively compact format without an additional optical instrument, such as a retardation compensator, a Michael-Levy chart, and a spectrophotometer, in order to determine the optical birefringence quantitatively.

Results: We demonstrate that bovine serum albumin immobilized on the gold surface of the cell hybrid interfaces that support both homeotropic and planar anchoring of LCs causes optical phase retardation change which can be determined quantitatively. We also provide estimation of the zenithal orientation of LCs near the gold surface of the hybrid interfaces, based on the phase retardation determined. The estimated limit of bovine serum albumin detection is approximately 2.1 μM.

Conclusion: This optical technique with LCs can serve an optical platform for label-free quantitative diagnosis of proteins in a real time manner.

No MeSH data available.


Schematic for measurement of cell optical birefringence using polarization-sensitive double-port detection.Abbreviations: λ/4, quarter-wave plate; λ/2, half-wave plate; PBS, polarizing beam splitter; BD, balanced detector; LCs, liquid crystals.
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f2-ijn-10-025: Schematic for measurement of cell optical birefringence using polarization-sensitive double-port detection.Abbreviations: λ/4, quarter-wave plate; λ/2, half-wave plate; PBS, polarizing beam splitter; BD, balanced detector; LCs, liquid crystals.

Mentions: A visible light source (He–Ne laser at the wavelength [λ] of 632.8 nm) at which LCs are transparent is passed through the optical cell of LCs, as shown in Figure 2. Circular polarization of light is secured at the input of the optical cell, using a quarter-wave plate (λ/4) placed before the optical cell of thickness d in order to ensure optimized detection of the birefringence of LCs regardless of their orientations inside the cell. This implies that an optical cell containing LCs does not need to be aligned at a specific azimuthal angle, unlike the measurement technique using two polarizers.


Optical birefringence of liquid crystals for label-free optical biosensing diagnosis.

Nguyen TT, Han GR, Jang CH, Ju H - Int J Nanomedicine (2015)

Schematic for measurement of cell optical birefringence using polarization-sensitive double-port detection.Abbreviations: λ/4, quarter-wave plate; λ/2, half-wave plate; PBS, polarizing beam splitter; BD, balanced detector; LCs, liquid crystals.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4554411&req=5

f2-ijn-10-025: Schematic for measurement of cell optical birefringence using polarization-sensitive double-port detection.Abbreviations: λ/4, quarter-wave plate; λ/2, half-wave plate; PBS, polarizing beam splitter; BD, balanced detector; LCs, liquid crystals.
Mentions: A visible light source (He–Ne laser at the wavelength [λ] of 632.8 nm) at which LCs are transparent is passed through the optical cell of LCs, as shown in Figure 2. Circular polarization of light is secured at the input of the optical cell, using a quarter-wave plate (λ/4) placed before the optical cell of thickness d in order to ensure optimized detection of the birefringence of LCs regardless of their orientations inside the cell. This implies that an optical cell containing LCs does not need to be aligned at a specific azimuthal angle, unlike the measurement technique using two polarizers.

Bottom Line: We also provide estimation of the zenithal orientation of LCs near the gold surface of the hybrid interfaces, based on the phase retardation determined.The estimated limit of bovine serum albumin detection is approximately 2.1 μM.This optical technique with LCs can serve an optical platform for label-free quantitative diagnosis of proteins in a real time manner.

View Article: PubMed Central - PubMed

Affiliation: Department of Bionano Technology, Gachon University, Seongnam-City, South Korea.

ABSTRACT

Purpose: We present a polarization-sensitive optical detection platform for label-free quantitative optical biosensing diagnosis using liquid crystals (LCs). This is capable of determining quantitatively the optical birefringence of optical cells containing LCs, whose orientation depends on the immobilized biomolecules.

Patients and methods: This technique uses a polarization-dependent double-port detection without any polarizer at a single wavelength and removes the need of aligning optical cells of LCs in the azimuthal direction, with respect to the light path through the optical cell. Thus, this technique enables a stand-alone detection in a relatively compact format without an additional optical instrument, such as a retardation compensator, a Michael-Levy chart, and a spectrophotometer, in order to determine the optical birefringence quantitatively.

Results: We demonstrate that bovine serum albumin immobilized on the gold surface of the cell hybrid interfaces that support both homeotropic and planar anchoring of LCs causes optical phase retardation change which can be determined quantitatively. We also provide estimation of the zenithal orientation of LCs near the gold surface of the hybrid interfaces, based on the phase retardation determined. The estimated limit of bovine serum albumin detection is approximately 2.1 μM.

Conclusion: This optical technique with LCs can serve an optical platform for label-free quantitative diagnosis of proteins in a real time manner.

No MeSH data available.