TY - JOUR
T1 - Encapsulation of Cadmium Selenide Nanocrystals in Biocompatible Nanotubes
T2 - DFT Calculations, X-ray Diffraction Investigations, and Confocal Fluorescence Imaging
AU - Calatayud, David G.
AU - Ge, Haobo
AU - Kuganathan, Navaratnarajah
AU - Mirabello, Vincenzo
AU - Jacobs, Robert M J
AU - Rees, Nicholas H.
AU - Stoppiello, Craig T.
AU - Khlobystov, Andrei N.
AU - Tyrrell, Rex M.
AU - Como, Enrico Da
AU - Pascu, Sofia I.
PY - 2018/2/1
Y1 - 2018/2/1
N2 - The encapsulation of CdSe nanocrystals within single-walled carbon nanotube (SWNT) cavities of varying dimensions at elevated temperatures under strictly air-tight conditions is described for the first time. The structures of CdSe nanocrystals under confinement inside SWNTs was established in a comprehensive study, combining both experimental and DFT theoretical investigations. The calculated binding energies show that all considered polymorphs [(3:3), (4:4), and (4:2)] may be obtained experimentally. The most thermodynamically stable structure (3:3) is directly compared to the experimentally observed CdSe structures inside carbon nanotubes. The gas-phase DFT-calculated energy difference between "free" 3:3 and 4:2 structures (whereby 3:3 models a novel tubular structure in which both Cd and Se form three coordination, as observed experimentally for HgTe inside SWNT, and 4:2 is a motif derived from the hexagonal CuI bulk structure in which both Cd and Se form 4 or 2 coordination) is surprisingly small, only 0.06eV per formula unit. X-ray powder diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray analyses led to the full characterization of the SWNTs filled with the CdSe nanocrystals, shedding light on the composition, structure, and electronic interactions of the new nanohybrid materials on an atomic level. A new emerging hybrid nanomaterial, simultaneously filled and beta-d-glucan coated, was obtained by using pristine nanotubes and bulk CdSe powder as starting materials. This displayed fluorescence in water dispersions and unexpected biocompatibility was found to be mediated by beta-d-glucan (a biopolymer extracted from barley) with respect to that of the individual inorganic material components. For the first time, such supramolecular nanostructures are investigated by life-science techniques applied to functional nanomaterial characterization, opening the door for future nano-biotechnological applications.
AB - The encapsulation of CdSe nanocrystals within single-walled carbon nanotube (SWNT) cavities of varying dimensions at elevated temperatures under strictly air-tight conditions is described for the first time. The structures of CdSe nanocrystals under confinement inside SWNTs was established in a comprehensive study, combining both experimental and DFT theoretical investigations. The calculated binding energies show that all considered polymorphs [(3:3), (4:4), and (4:2)] may be obtained experimentally. The most thermodynamically stable structure (3:3) is directly compared to the experimentally observed CdSe structures inside carbon nanotubes. The gas-phase DFT-calculated energy difference between "free" 3:3 and 4:2 structures (whereby 3:3 models a novel tubular structure in which both Cd and Se form three coordination, as observed experimentally for HgTe inside SWNT, and 4:2 is a motif derived from the hexagonal CuI bulk structure in which both Cd and Se form 4 or 2 coordination) is surprisingly small, only 0.06eV per formula unit. X-ray powder diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray analyses led to the full characterization of the SWNTs filled with the CdSe nanocrystals, shedding light on the composition, structure, and electronic interactions of the new nanohybrid materials on an atomic level. A new emerging hybrid nanomaterial, simultaneously filled and beta-d-glucan coated, was obtained by using pristine nanotubes and bulk CdSe powder as starting materials. This displayed fluorescence in water dispersions and unexpected biocompatibility was found to be mediated by beta-d-glucan (a biopolymer extracted from barley) with respect to that of the individual inorganic material components. For the first time, such supramolecular nanostructures are investigated by life-science techniques applied to functional nanomaterial characterization, opening the door for future nano-biotechnological applications.
KW - Beta-d-glucan encapsulation
KW - Cadmium selenide functional nanohybrids
KW - Density functional calculations
KW - Functional and fluorescent biocompatible nanotube hybrids
KW - Self-assembly
UR - http://www.scopus.com/inward/record.url?scp=85040734911&partnerID=8YFLogxK
U2 - 10.1002/open.201700184
DO - 10.1002/open.201700184
M3 - Article
C2 - 29435400
AN - SCOPUS:85040734911
VL - 7
SP - 144
EP - 158
JO - ChemistryOpen
JF - ChemistryOpen
IS - 2
ER -