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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.


(a) PMMA mold and (b) PDMS hybrid lens.
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f3-sensors-14-02967: (a) PMMA mold and (b) PDMS hybrid lens.

Mentions: The polymethylmethacrylate (PMMA) mold for casting the hybrid lens is made by a CNC laser cutting machine (Mcl Recruitment, Blackburn, UK). PMMA is chosen because it is easy to modify and has a relatively smooth surface. Polydimethylsiloxane (PDMS, RTV 615, Momentive, Waterford, NY, USA) is used as the material to replicate the hybrid lens. A desired amount of mixed PDMS solution (A:B = 10:1) is poured over the mold and vacuum is applied for 20 min to remove bubbles in the mixture. The PDMS mixture is then cured in the oven at 150 °C for 10 min and the cured sheet is peeled off of the mold. Figure 3a,b shows the PMMA mold and the replicated PMDS hybrid lens, respectively.


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)

(a) PMMA mold and (b) PDMS hybrid lens.
© Copyright Policy
Related In: Results  -  Collection

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

f3-sensors-14-02967: (a) PMMA mold and (b) PDMS hybrid lens.
Mentions: The polymethylmethacrylate (PMMA) mold for casting the hybrid lens is made by a CNC laser cutting machine (Mcl Recruitment, Blackburn, UK). PMMA is chosen because it is easy to modify and has a relatively smooth surface. Polydimethylsiloxane (PDMS, RTV 615, Momentive, Waterford, NY, USA) is used as the material to replicate the hybrid lens. A desired amount of mixed PDMS solution (A:B = 10:1) is poured over the mold and vacuum is applied for 20 min to remove bubbles in the mixture. The PDMS mixture is then cured in the oven at 150 °C for 10 min and the cured sheet is peeled off of the mold. Figure 3a,b shows the PMMA mold and the replicated PMDS hybrid lens, respectively.

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.