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A PDMS-based cylindrical hybrid lens for enhanced fluorescence detection in microfluidic systems.

Lin BS, Yang YC, Ho CY, Yang HY, Wang HY - Sensors (Basel) (2014)

Bottom Line: Moreover, PDMS has advantages of low-cost and straightforward fabrication compared with conventional optical components.The performance of the proposed lens is first examined with two fluorescent dyes and the results show that the lens provides satisfactory enhancement for fluorescence detection of Rhodamine 6G and Nile Red.The overall increments in collected fluorescence signal and detection sensitivity are more than 220% of those without lens, and the detection limits of Rhodamine 6G and Nile red are lowered to 0.01 μg/mL and 0.05 μg/mL, respectively.

View Article: PubMed Central - PubMed

Affiliation: Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan 71150, Taiwan. borshyhlin@mail.nctu.edu.tw.

ABSTRACT
Microfluidic systems based on fluorescence detection have been developed and applied for many biological and chemical applications. Because of the tiny amount of sample in the system; the induced fluorescence can be weak. Therefore, most microfluidic systems deploy multiple optical components or sophisticated equipment to enhance the efficiency of fluorescence detection. However, these strategies encounter common issues of complex manufacturing processes and high costs. In this study; a miniature, cylindrical and hybrid lens made of polydimethylsiloxane (PDMS) to improve the fluorescence detection in microfluidic systems is proposed. The hybrid lens integrates a laser focusing lens and a fluorescence collecting lens to achieve dual functions and simplify optical setup. Moreover, PDMS has advantages of low-cost and straightforward fabrication compared with conventional optical components. The performance of the proposed lens is first examined with two fluorescent dyes and the results show that the lens provides satisfactory enhancement for fluorescence detection of Rhodamine 6G and Nile Red. The overall increments in collected fluorescence signal and detection sensitivity are more than 220% of those without lens, and the detection limits of Rhodamine 6G and Nile red are lowered to 0.01 μg/mL and 0.05 μg/mL, respectively. The hybrid lens is further applied to the detection of Nile red-labeled Chlorella vulgaris cells and it increases both signal intensity and detection sensitivity by more than 520%. The proposed hybrid lens also dramatically reduces the variation in detected signal caused by the deviation in incident angle of excitation light.

No MeSH data available.


System scheme of PDMS-based cylindrical hybrid lens used in microfluidics.
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f1-sensors-14-02967: System scheme of PDMS-based cylindrical hybrid lens used in microfluidics.

Mentions: The optical system with the proposed miniature hybrid cylindrical lens for laser focusing and fluorescence collecting is shown in Figure 1. The two lenses are integrated on a PDMS backboard. The incident laser enters the hybrid lens and then is focused just below the glass slide. The microfluidic device is positioned below the collecting lens with the glass slide facing the lens. A spectrometer is placed at the focal point of the collecting lens. Focusing the excitation light is beneficial for enhancing the induced fluorescence. Additionally, it also increases the signal to noise ratio (SNR) by reducing the effects from strayed or environmental light. The more efficient the focusing is, the more fluorescence could be induced and detected. The dimensions and characteristic parameters of the laser focusing lens, the fluorescence collecting lens, and the hybrid lens are shown in Figure 2 and Table 1.


A PDMS-based cylindrical hybrid lens for enhanced fluorescence detection in microfluidic systems.

Lin BS, Yang YC, Ho CY, Yang HY, Wang HY - Sensors (Basel) (2014)

System scheme of PDMS-based cylindrical hybrid lens used in microfluidics.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3958222&req=5

f1-sensors-14-02967: System scheme of PDMS-based cylindrical hybrid lens used in microfluidics.
Mentions: The optical system with the proposed miniature hybrid cylindrical lens for laser focusing and fluorescence collecting is shown in Figure 1. The two lenses are integrated on a PDMS backboard. The incident laser enters the hybrid lens and then is focused just below the glass slide. The microfluidic device is positioned below the collecting lens with the glass slide facing the lens. A spectrometer is placed at the focal point of the collecting lens. Focusing the excitation light is beneficial for enhancing the induced fluorescence. Additionally, it also increases the signal to noise ratio (SNR) by reducing the effects from strayed or environmental light. The more efficient the focusing is, the more fluorescence could be induced and detected. The dimensions and characteristic parameters of the laser focusing lens, the fluorescence collecting lens, and the hybrid lens are shown in Figure 2 and Table 1.

Bottom Line: Moreover, PDMS has advantages of low-cost and straightforward fabrication compared with conventional optical components.The performance of the proposed lens is first examined with two fluorescent dyes and the results show that the lens provides satisfactory enhancement for fluorescence detection of Rhodamine 6G and Nile Red.The overall increments in collected fluorescence signal and detection sensitivity are more than 220% of those without lens, and the detection limits of Rhodamine 6G and Nile red are lowered to 0.01 μg/mL and 0.05 μg/mL, respectively.

View Article: PubMed Central - PubMed

Affiliation: Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan 71150, Taiwan. borshyhlin@mail.nctu.edu.tw.

ABSTRACT
Microfluidic systems based on fluorescence detection have been developed and applied for many biological and chemical applications. Because of the tiny amount of sample in the system; the induced fluorescence can be weak. Therefore, most microfluidic systems deploy multiple optical components or sophisticated equipment to enhance the efficiency of fluorescence detection. However, these strategies encounter common issues of complex manufacturing processes and high costs. In this study; a miniature, cylindrical and hybrid lens made of polydimethylsiloxane (PDMS) to improve the fluorescence detection in microfluidic systems is proposed. The hybrid lens integrates a laser focusing lens and a fluorescence collecting lens to achieve dual functions and simplify optical setup. Moreover, PDMS has advantages of low-cost and straightforward fabrication compared with conventional optical components. The performance of the proposed lens is first examined with two fluorescent dyes and the results show that the lens provides satisfactory enhancement for fluorescence detection of Rhodamine 6G and Nile Red. The overall increments in collected fluorescence signal and detection sensitivity are more than 220% of those without lens, and the detection limits of Rhodamine 6G and Nile red are lowered to 0.01 μg/mL and 0.05 μg/mL, respectively. The hybrid lens is further applied to the detection of Nile red-labeled Chlorella vulgaris cells and it increases both signal intensity and detection sensitivity by more than 520%. The proposed hybrid lens also dramatically reduces the variation in detected signal caused by the deviation in incident angle of excitation light.

No MeSH data available.