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Dopamine-functionalized InP/ZnS quantum dots as fluorescence probes for the detection of adenosine in microfluidic chip.

Ankireddy SR, Kim J - Int J Nanomedicine (2015)

Bottom Line: Microbeads are frequently used as solid supports for biomolecules such as proteins and nucleic acids in heterogeneous microfluidic assays.The photoluminescence (PL) intensity of the QDs-DA is quenched by Zn(2+) because of the strong coordination interactions.In the presence of adenosine, Zn(2+) cations preferentially bind to adenosine, and the PL intensity of the QDs-DA is recovered.

View Article: PubMed Central - PubMed

Affiliation: Department of chemical and Biological Engineering, Gachon University, Seongnam, Gyeonggi-Do, South Korea.

ABSTRACT
Microbeads are frequently used as solid supports for biomolecules such as proteins and nucleic acids in heterogeneous microfluidic assays. Chip-based, quantum dot (QD)-bead-biomolecule probes have been used for the detection of various types of DNA. In this study, we developed dopamine (DA)-functionalized InP/ZnS QDs (QDs-DA) as fluorescence probes for the detection of adenosine in microfluidic chips. The photoluminescence (PL) intensity of the QDs-DA is quenched by Zn(2+) because of the strong coordination interactions. In the presence of adenosine, Zn(2+) cations preferentially bind to adenosine, and the PL intensity of the QDs-DA is recovered. A polydimethylsiloxane-based microfluidic chip was fabricated, and adenosine detection was confirmed using QDs-DA probes.

No MeSH data available.


Related in: MedlinePlus

Fluorescence microscope images of beads-QDs-DA in microfluidic channel under (A) bright field and (B) dark field conditions, and (C) beads-QDs-DA packed in PDMS chip as a function of time after introduction of Zn2+ solution.Abbreviations: DA, dopamine; QDs, quantum dots; PDMS, polydimethylsiloxane; min, minutes.
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f6-ijn-10-121: Fluorescence microscope images of beads-QDs-DA in microfluidic channel under (A) bright field and (B) dark field conditions, and (C) beads-QDs-DA packed in PDMS chip as a function of time after introduction of Zn2+ solution.Abbreviations: DA, dopamine; QDs, quantum dots; PDMS, polydimethylsiloxane; min, minutes.

Mentions: Figure 6 shows the fluorescence microscope images of beads-QDs-DA in the microfluidic channel under (A) bright field and (B) dark field conditions, and (C) as a function of time after introduction of Zn2+ solution. The figure shows that the QDs are well bound to the polystyrene bead surfaces, and the microfluidic chip channels are filled with beads-QDs-DA. All reaction solutions were injected into the microchannel by using syringe pump. Initially, the microchannel was washed with DI water, and Zn2+ and adenosine were injected into the microchannel for 30 minutes. After injection of Zn2+ using a syringe pump, the fluorescence microscope images were recorded as a function of time. The fluorescence intensity was measured by image scanning over specific areas of the channel. After injection of Zn2+ solution, the fluorescence images on the microchannel were quantified by using image analysis program (IM-1 2005) and redrawn as intensity line profile and also the fluorescence intensity per minute at 360 pixel of line profiles were averaged and converted to intensity profile as a function of time as shown in Figure 6. The fluorescence emission intensity from QDs attached to microbeads decreased gradually due to strong affinity between Zn2+ and adenosine. After 30 minutes, it was very difficult to observe further change of the fluorescence intensity, which may be due to the saturation of preferential binding of Zn2+ to adenosine.


Dopamine-functionalized InP/ZnS quantum dots as fluorescence probes for the detection of adenosine in microfluidic chip.

Ankireddy SR, Kim J - Int J Nanomedicine (2015)

Fluorescence microscope images of beads-QDs-DA in microfluidic channel under (A) bright field and (B) dark field conditions, and (C) beads-QDs-DA packed in PDMS chip as a function of time after introduction of Zn2+ solution.Abbreviations: DA, dopamine; QDs, quantum dots; PDMS, polydimethylsiloxane; min, minutes.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4554435&req=5

f6-ijn-10-121: Fluorescence microscope images of beads-QDs-DA in microfluidic channel under (A) bright field and (B) dark field conditions, and (C) beads-QDs-DA packed in PDMS chip as a function of time after introduction of Zn2+ solution.Abbreviations: DA, dopamine; QDs, quantum dots; PDMS, polydimethylsiloxane; min, minutes.
Mentions: Figure 6 shows the fluorescence microscope images of beads-QDs-DA in the microfluidic channel under (A) bright field and (B) dark field conditions, and (C) as a function of time after introduction of Zn2+ solution. The figure shows that the QDs are well bound to the polystyrene bead surfaces, and the microfluidic chip channels are filled with beads-QDs-DA. All reaction solutions were injected into the microchannel by using syringe pump. Initially, the microchannel was washed with DI water, and Zn2+ and adenosine were injected into the microchannel for 30 minutes. After injection of Zn2+ using a syringe pump, the fluorescence microscope images were recorded as a function of time. The fluorescence intensity was measured by image scanning over specific areas of the channel. After injection of Zn2+ solution, the fluorescence images on the microchannel were quantified by using image analysis program (IM-1 2005) and redrawn as intensity line profile and also the fluorescence intensity per minute at 360 pixel of line profiles were averaged and converted to intensity profile as a function of time as shown in Figure 6. The fluorescence emission intensity from QDs attached to microbeads decreased gradually due to strong affinity between Zn2+ and adenosine. After 30 minutes, it was very difficult to observe further change of the fluorescence intensity, which may be due to the saturation of preferential binding of Zn2+ to adenosine.

Bottom Line: Microbeads are frequently used as solid supports for biomolecules such as proteins and nucleic acids in heterogeneous microfluidic assays.The photoluminescence (PL) intensity of the QDs-DA is quenched by Zn(2+) because of the strong coordination interactions.In the presence of adenosine, Zn(2+) cations preferentially bind to adenosine, and the PL intensity of the QDs-DA is recovered.

View Article: PubMed Central - PubMed

Affiliation: Department of chemical and Biological Engineering, Gachon University, Seongnam, Gyeonggi-Do, South Korea.

ABSTRACT
Microbeads are frequently used as solid supports for biomolecules such as proteins and nucleic acids in heterogeneous microfluidic assays. Chip-based, quantum dot (QD)-bead-biomolecule probes have been used for the detection of various types of DNA. In this study, we developed dopamine (DA)-functionalized InP/ZnS QDs (QDs-DA) as fluorescence probes for the detection of adenosine in microfluidic chips. The photoluminescence (PL) intensity of the QDs-DA is quenched by Zn(2+) because of the strong coordination interactions. In the presence of adenosine, Zn(2+) cations preferentially bind to adenosine, and the PL intensity of the QDs-DA is recovered. A polydimethylsiloxane-based microfluidic chip was fabricated, and adenosine detection was confirmed using QDs-DA probes.

No MeSH data available.


Related in: MedlinePlus