Formation of water-soluble and biocompatible TOPO-capped CdSe quantum dots with efficient photoluminescence.
In this work, polysorbate surfactants with same functional groups but with varying molecular masses (Tween-80, Tween-40 and Tween-20) in different concentrations (0.1% to 20% w/w) were used to study the effect of the length of the surfactant chain on the luminescence of the entrapped TOPO-capped CdSe nanocrystals. Various phospholipids with different functional headgroups such as ethylene glycol (-PEG) and amine (-NH2) were used to improve biocompatibility and provide sites for bioconjugation respectively. It is understood that that the hydrophobic ends of the surfactant binds with the water repelling groups of the cap layer, thus modifying the CdSe cap layer and making it soluble in aqueous media. It was observed that the PL emission intensity of CdSe increases with increase in concentration of Tween-series surfactant unlike in the case of thiol-coated CdSe nanoparticles. However, higher PL intensity was obtained in the case of stoichiometric CdSe with Tween-40 corresponding to 20% w/w. The efficient PL sustainability of water-soluble CdSe QD's can be attributed to the simpler chain structure of Tween-40 surfactant resulting in better passivation of the micelle.
Electronic Materials Division, National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110 012, India.
Himani
H
Sharma
Shailesh N
SN
Sharma
Umesh
U
Kumar
V N
VN
Singh
B R
BR
Mehta
Gurmeet
G
Singh
S M
SM
Shivaprasad
Rita
R
Kakkar
D015502:Absorptiometry, Photon; D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000737:chemistry; D019187:Cadmium Compounds / Q000737:chemistry*; D004526:Efficiency; D049449:Luminescence; D008823:Micelles; D008954:Models, Biological; D009943:Organophosphorus Compounds / Q000737:chemistry; D011136:Polysorbates / Q000494:pharmacology; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D012995:Solubility; D013501:Surface-Active Agents / Q000494:pharmacology; D014867:Water / Q000737:chemistry / Q000494:pharmacology
D001672:Biocompatible Materials; D019187:Cadmium Compounds; D008823:Micelles; D009943:Organophosphorus Compounds; D011136:Polysorbates; D018036:Selenium Compounds; D013501:Surface-Active Agents; D014867:Water; C044965:trioctyl phosphine oxide; C058667:cadmium selenide; C068430:polysorbate 40