Multifunctional microgel magnetic/optical traps for SERS ultradetection.

We report on the fabrication of a SERS substrate comprising magnetic and silver particles encapsulated within a poly(N-isopropylacrylamide) (pNIPAM) thermoresponsive microgel. This colloidal substrate has the ability to adsorb analytes from solution while it is expanded (low temperature) and reversibly generate hot spots upon collapse (high temperature or drying). Additionally, the magnetic functionality permits concentration of the composite particles into small spatial regions, which can be exploited to decrease the amount of material per analysis while improving its SERS detection limit. Proof of concept for the sequestration of uncommon molecular systems is demonstrated through the first SERS analysis of pentachlorophenol (PCP), a chlorinated ubiquitous environmental pollutant.

[1]  Yong Qian,et al.  In Situ controllable preparation of gold nanorods in thermo-responsive hydrogels and their application in surface enhanced Raman scattering , 2010 .

[2]  M. Moskovits.  Spectroscopy: Expanding versatility , 2010, Nature.

[3]  P. Guardia,et al.  Controlled synthesis of iron oxide nanoparticles over a wide size range. , 2010, Langmuir : the ACS journal of surfaces and colloids.

[4]  L. Liz‐Marzán,et al.  Heating rate influence on the synthesis of iron oxide nanoparticles: the case of decanoic acid. , 2010, Chemical communications.

[5]  George C Schatz,et al.  TDDFT studies of absorption and SERS spectra of pyridine interacting with Au20. , 2006, The journal of physical chemistry. A.

[6]  R. V. Van Duyne,et al.  Probing the structure of single-molecule surface-enhanced Raman scattering hot spots. , 2008, Journal of the American Chemical Society.

[7]  Luis M Liz-Marzán,et al.  Au@pNIPAM colloids as molecular traps for surface-enhanced, spectroscopic, ultra-sensitive analysis. , 2009, Angewandte Chemie.

[8]  L. Liz‐Marzán,et al.  SERS-based diagnosis and biodetection. , 2010, Small.

[9]  N. Shah,et al.  Surface-enhanced Raman spectroscopy. , 2008, Annual review of analytical chemistry.

[10]  R. Álvarez-Puebla,et al.  Synthesis of silver nanoparticles with controllable surface charge and their application to surface-enhanced Raman scattering. , 2009, Analytical chemistry.

[11]  Chad A Mirkin,et al.  Gold nanoparticles for biology and medicine. , 2010, Angewandte Chemie.

[12]  K. Kneipp,et al.  SERS--a single-molecule and nanoscale tool for bioanalytics. , 2008, Chemical Society reviews.

[13]  María del Puerto Morales,et al.  Static and dynamic magnetic properties of spherical magnetite nanoparticles , 2003 .

[14]  C. Domingo,et al.  Sensing polycyclic aromatic hydrocarbons with dithiocarbamate-functionalized ag nanoparticles by surface-enhanced Raman scattering. , 2009, Analytical chemistry.

[15]  L. Liz‐Marzán,et al.  Bifunctional Nanocomposites with Long-Term Stability as SERS Optical Accumulators for Ultrasensitive Analysis , 2009 .

[16]  Vincent M. Rotello,et al.  Applications of Nanoparticles in Biology , 2008 .

[17]  C. Serna,et al.  Nanostructural origin of the spin and orbital contribution to the magnetic moment in Fe3−xO4 magnetite nanoparticles , 2009 .

[18]  M. Moskovits.  Surface‐enhanced Raman spectroscopy: a brief retrospective , 2005 .

[19]  W. Tseng,et al.  Impacts that pH and metal ion concentration have on the synthesis of bimetallic and trimetallic nanorods from gold seeds , 2005 .

[20]  Huan‐Tsung Chang,et al.  Synthesis of dumbbell-shaped Au-Ag core-shell nanorods by seed-mediated growth under alkaline conditions. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[21]  L. Liz‐Marzán,et al.  Light concentration at the nanometer scale , 2010 .

[22]  Christy L Haynes,et al.  Partition layer-modified substrates for reversible surface-enhanced Raman scattering detection of polycyclic aromatic hydrocarbons , 2009, Analytical and bioanalytical chemistry.

[23]  Yan Lu,et al.  Thermosensitive core-shell particles as carriers for ag nanoparticles: modulating the catalytic activity by a phase transition in networks. , 2006, Angewandte Chemie.

[24]  Logan K. Ausman,et al.  Methods for describing the electromagnetic properties of silver and gold nanoparticles. , 2008, Accounts of chemical research.

[25]  R. Dasari,et al.  Ultrasensitive chemical analysis by Raman spectroscopy. , 1999, Chemical reviews.

[26]  C. Haynes,et al.  Surface-enhanced Raman scattering detection and discrimination of polychlorinated biphenyls , 2009 .

[27]  Younan Xia,et al.  Probing the surface-enhanced Raman scattering properties of Au-Ag nanocages at two different excitation wavelengths. , 2009, Physical chemistry chemical physics : PCCP.

[28]  C. Domingo,et al.  Functionalization of Ag nanoparticles with dithiocarbamate calix[4]arene as an effective supramolecular host for the surface-enhanced Raman scattering detection of polycyclic aromatic hydrocarbons. , 2006, Langmuir : the ACS journal of surfaces and colloids.

[29]  Luis M Liz-Marzán,et al.  Label-free SERS detection of relevant bioanalytes on silver-coated carbon nanotubes: The case of cocaine. , 2009, Nanoscale.

[30]  Marc D Porter,et al.  SERS as a bioassay platform: fundamentals, design, and applications. , 2008, Chemical Society reviews.

[31]  Naomi J Halas,et al.  Direct optical detection of aptamer conformational changes induced by target molecules. , 2009, Analytical chemistry.

[32]  L. Liz‐Marzán,et al.  Growing Au/Ag nanoparticles within microgel colloids for improved surface-enhanced Raman scattering detection. , 2010, Chemistry.

[33]  Martin Moskovits,et al.  Aptamer-mediated surface-enhanced Raman spectroscopy intensity amplification. , 2010, Nano letters.

[34]  A. Pawlukojć,et al.  Inelastic neutron scattering studies on low frequency vibrations of pentachlorophenol. , 2001, Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy.

[35]  Matthias Karg,et al.  Multiresponsive hybrid colloids based on gold nanorods and poly(NIPAM-co-allylacetic acid) microgels: temperature- and pH-tunable plasmon resonance. , 2009, Langmuir : the ACS journal of surfaces and colloids.

[36]  T. Laurence,et al.  Rapid, solution-based characterization of optimized SERS nanoparticle substrates. , 2009, Journal of the American Chemical Society.

[37]  Luis M Liz-Marzán,et al.  Recyclable molecular trapping and SERS detection in silver-loaded agarose gels with dynamic hot spots. , 2009, Analytical chemistry.

[38]  Chad A Mirkin,et al.  Nanostructures in biodiagnostics. , 2005, Chemical reviews.

[39]  Matthias Karg,et al.  Nanorod-coated PNIPAM microgels: thermoresponsive optical properties. , 2007, Small.

[40]  A. Bodour,et al.  Prioritizing research for trace pollutants and emerging contaminants in the freshwater environment. , 2010, Environmental pollution.

[41]  G. Swain,et al.  Chlorinated phenol analysis using off-line solid-phase extraction and capillary electrophoresis coupled with amperometric detection and a boron-doped diamond microelectrode. , 2005, Analytical chemistry.

[42]  Luis M. Liz-Marzán,et al.  Environmental applications of plasmon assisted Raman scattering , 2010 .