Aqueous synthesis of L-cysteine stabilized water dispersible CdS:Mn quantum dots for biosensing applications

Kumar, Parveen and Kumar, Pawan and Bharadwaj, L.M. and Paul, A.K. and Sharma, S.C. and Kush, Preeti and Deep, Akash (2013) Aqueous synthesis of L-cysteine stabilized water dispersible CdS:Mn quantum dots for biosensing applications. BioNanoScience, 3 (2). pp. 95-101. ISSN 2191-1630 (Print) 2191-1649 (Online)

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The present work reports the aqueous synthesis of l-cysteine (2-amino 3-mercaptopropionic acid) capped manganese-doped cadmium sulphide quantum dots (QDs). l-Cysteine functions both as a sulfur source and the stabilizer during the synthesis. The product collected at different time intervals during the reaction showed red shifts in their absorption onsets (peak shifts 380 → 395 → 420 nm) and respective emission (peak shifts 585 → 610 → 660 nm) onsets. Nanoparticles of the average size of 3 ± 0.5 nm were obtained. Based on the theoretical calculations, the maximum band gap energy of the synthesized nanocrystals is found to be 2.83 eV. Fourier transform infrared and Raman spectroscopic studies have confirmed the presence of carboxylic and amine functional groups. Atomic force and electron microscopic techniques have verified the formation of the nanosized QDs. Energy dispersive X-ray spectrometry has confirmed the doping of manganese in the CdS structure, while X-ray diffractometry established the crystal structure as of zinc blend type. The proposed l-cysteine capped CdS:Mn QDs can be termed as multifunctional crystals, which are useful for the assembly of fluorescent molecular probes for clinical analysis and disease diagnosis. The proposed nanocrystals can also be potentially used as contrast agents in the magnetic resonance imaging due to the presence of manganese.

Item Type: Article
Uncontrolled Keywords: Quantum dots; Doping; Photoluminescence; Bioconjugation; l-Cysteine
Subjects: CSIO > Nano Science and Nano Technology
Divisions: Nano Science and Nano Technology
Depositing User: Ms. Jyotsana
Date Deposited: 04 May 2017 13:27
Last Modified: 04 May 2017 13:27

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