Quantum dots as nano plug-in's for efficient NADH resonance energy routing.
The routing of fluorescent signals from NADH to quantum dots (QDs) has been a subject of extensive research for FRET based applications. In the present study, the spectral cross talk of NAD(+)/NADH with QDs was used to monitor the reaction of NAD(+)-dependent dehydrogenase enzyme. CdTe QD may undergo dipolar interaction with NADH as a result of broad spectral absorption due to multiple excitonic states resulting from quantum confinement effects. Thus, non-radiative energy transfer can take place from NADH to CdTe QD enhancing QDs fluorescence. Energy routing assay of NADH-QD was applied for detection of formaldehyde as a model analyte in the range 1000-0.01 ng/mL by the proposed technique. We observed proportionate quenching of CdTe QD fluorescence by NAD(+) and enhancement in the presence of NADH formed by various concentrations of enzyme (0.028-0.4 U). Hence, it was possible to detect formaldehyde in the range 1000-0.01 ng/mL with a limit of detection (LOD) at 0.01 ng/mL and regression coefficient R(2)=0.9982. Therefore, a unique optical sensor was developed for the detection of the formaldehyde in sensitive level based on the above mechanism. This method can be used to follow the activity of NAD(+)-dependent enzymes and detection of dehydrogenases in general.
Fermentation Technology and Bioengineering Department, Central Food Technological Research Institute (A Constituent Laboratory of Council of Scientific and Industrial Research, New Delhi), Mysore 570020, India.
Uchangi Satyaprasad
US
Akshath
Aaydha Chidambara
AC
Vinayaka
Munna Singh
MS
Thakur
D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D019187:Cadmium Compounds / Q000737:chemistry*; D004735:Energy Transfer; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry*; D005557:Formaldehyde / Q000032:analysis* / Q000378:metabolism; D057230:Limit of Detection; D009243:NAD / Q000737:chemistry / Q000378:metabolism*; D045663:Quantum Dots; D013691:Tellurium / Q000737:chemistry*
D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D009243:NAD; D005557:Formaldehyde; D000445:Aldehyde Oxidoreductases; C087006:formaldehyde dehydrogenase, glutathione-independent; D013691:Tellurium; C028337:cadmium telluride