Optical biosensor based on cadmium sulfide-silver nanoplate hybrid structure

Research on surface plasmons (SPs), one of the major field in nanophotonics, explores the properties of a confined electromagnetic field over dimensions in the order of or smaller than the working wavelength. The present work focuses on the impact of SPs on the photophysical properties of chromophore, especially in photoluminescence (PL) enhancement. In the applications of SPs in bio-labeling, the modulation of active nanoparticles with noble metallic nanoparticles is a prerequisite and has provided fundamental research interest. The modulation of cadmium (Cd) chalocogenides nanoparticles with silver (Ag) nanoparticles emerges against a number of technical issues, such as forward cationic ion exchange in mutual nanoparticles, conjugation efficiency, and occurrence of PL quenching in very close mutual distance (smaller than 5 nm). To overcome these challenges cadmium sulfide (CdS) and Ag nanoplate (CdS-Ag NP) hybrid is synthesized by a forward-reverse cation exchange. The morphology, crystallinity, and atomic composition of the CdSAg NPs have been investigated using energy dispersive X-Ray spectroscopy and high resolution transmission electron spectroscopy. The CdS-Ag NPs are Cd2+-rich CdS nanoparticles covalently bonded to the surfactant of the Ag NPs. PL enhancement of measured CdS is attributed to the matching of the emission bands of CdS and the tailor-made localized surface plasmon resonance (LSPR) bands provided by the Ag NP. In addition, CdS-Ag NP in HeLa cell imaging has also been demonstrated, and no apoptosis was observed. The results provide a simple and flexible methodology for conjugating complex nanoparticles, thus offering promising practical applications in nanotechnology.

[1]  J. Lakowicz,et al.  Emission Spectral Properties of Cadmium Sulfide Nanoparticles with Multiphoton Excitation. , 2002, The journal of physical chemistry. B.

[2]  Yadong Yin,et al.  Cation Exchange Reactions in Ionic Nanocrystals , 2004, Science.

[3]  Andrew Y. Wang,et al.  Bright and color-saturated emission from blue light emitting diodes based on solution-processed colloidal nanocrystal quantum dots , 2008, 2008 Conference on Lasers and Electro-Optics and 2008 Conference on Quantum Electronics and Laser Science.

[4]  J. Storhoff,et al.  Selective colorimetric detection of polynucleotides based on the distance-dependent optical properties of gold nanoparticles. , 1997, Science.

[5]  Younan Xia,et al.  Triangular Nanoplates of Silver: Synthesis, Characterization, and Use as Sacrificial Templates For Generating Triangular Nanorings of Gold , 2003 .

[6]  C. Haynes,et al.  Nanosphere lithography: Tunable localized surface plasmon resonance spectra of silver nanoparticles , 2000 .

[7]  M. El-Sayed,et al.  Nuclear targeting of gold nanoparticles in cancer cells induces DNA damage, causing cytokinesis arrest and apoptosis. , 2010, Journal of the American Chemical Society.

[8]  Adam D. McFarland,et al.  Single Silver Nanoparticles as Real-Time Optical Sensors with Zeptomole Sensitivity , 2003 .

[9]  L. Novotný,et al.  Enhancement and quenching of single-molecule fluorescence. , 2006, Physical review letters.

[10]  M. Ouyang,et al.  Tailoring light–matter–spin interactions in colloidal hetero-nanostructures , 2010, Nature.

[11]  Younan Xia,et al.  Cation exchange: a simple and versatile route to inorganic colloidal spheres with the same size but different compositions and properties. , 2007, Langmuir : the ACS journal of surfaces and colloids.

[12]  C. Mirkin,et al.  Photoinduced Conversion of Silver Nanospheres to Nanoprisms , 2001, Science.

[13]  Yun Chen,et al.  Quantum dots for labeling live cells. , 2012, Methods in molecular biology.

[14]  A. I. Kryukov,et al.  Quantum Size Effects and Nature of Photoprocesses in Nanoparticles of Ag2S , 2001 .

[15]  C. Mirkin,et al.  Nanoparticles with Raman spectroscopic fingerprints for DNA and RNA detection. , 2002, Science.

[16]  S. Gambhir,et al.  Quantum Dots for Live Cells, in Vivo Imaging, and Diagnostics , 2005, Science.

[17]  W. Marsden.  I and J , 2012 .

[18]  M. Ouyang,et al.  Nonepitaxial Growth of Hybrid Core-Shell Nanostructures with Large Lattice Mismatches , 2010, Science.

[19]  P. Guyot-Sionnest,et al.  Preparation and optical properties of silver chalcogenide coated gold nanorods , 2006 .