TY - JOUR
T1 - Layer-by-layer coating of bacteria with noble metal nanoparticles for surface-enhanced Raman scattering
AU - Kahraman, Mehmet
AU - Zamaleeva, Alsu I.
AU - Fakhrullin, Rawil F.
AU - Culha, Mustafa
N1 - Funding Information:
Acknowledgments The authors greatly acknowledge the financial support of Yeditepe University during the course of this study. The authors also thank to Prof. Dr. Fikrettin Şahin and Prof. Sesin Kocagöz for their generous donations of S. cohnii and E. coli, respectively. Mehmet Kahraman and Alsu I. Zamaleeva contributed equally to this study.
PY - 2009/12
Y1 - 2009/12
N2 - A simple layer-by-layer method to coat the bacterial cells with gold and silver nanoparticles (AuNPs and AgNPs) for the acquisition of surface-enhanced Raman scattering (SERS) spectra is reported. First, the bacteria cell wall is coated with poly (allylamine hydrochloride) (PAH), a positively charged polymer, and then with citrate reduced Au or AgNPs. In order to increase the stability of the coating, another layer of PAH is prepared on the surface. The SEM and AFM images indicate that the nanoparticles are in the form of both isolated and aggregated nanoparticles on the bacterial wall. The coating of bacterial cells with AgNPs or AuNPs not only serves for their preparation for SERS measurement but also helps to visualize the coated of bacterial cells under the ordinary white-light microscope objective due to efficient light-scattering properties of Au and AgNPs. A comparative study single versus aggregates of bacterial cells is also demonstrated for possible single bacterial detection with SERS. The two bacteria that differ in shape and cell wall biochemical structure, Escherichia coli and Staphylococcus cohnii, Gram-negative and -positive, respectively, are used as models. The preliminary results reveal that the approach could be used for single bacterial cell identification.
AB - A simple layer-by-layer method to coat the bacterial cells with gold and silver nanoparticles (AuNPs and AgNPs) for the acquisition of surface-enhanced Raman scattering (SERS) spectra is reported. First, the bacteria cell wall is coated with poly (allylamine hydrochloride) (PAH), a positively charged polymer, and then with citrate reduced Au or AgNPs. In order to increase the stability of the coating, another layer of PAH is prepared on the surface. The SEM and AFM images indicate that the nanoparticles are in the form of both isolated and aggregated nanoparticles on the bacterial wall. The coating of bacterial cells with AgNPs or AuNPs not only serves for their preparation for SERS measurement but also helps to visualize the coated of bacterial cells under the ordinary white-light microscope objective due to efficient light-scattering properties of Au and AgNPs. A comparative study single versus aggregates of bacterial cells is also demonstrated for possible single bacterial detection with SERS. The two bacteria that differ in shape and cell wall biochemical structure, Escherichia coli and Staphylococcus cohnii, Gram-negative and -positive, respectively, are used as models. The preliminary results reveal that the approach could be used for single bacterial cell identification.
KW - Gold and silver nanoparticles
KW - Layer-by-layer
KW - SERS
KW - Single bacterium
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U2 - 10.1007/s00216-009-3159-0
DO - 10.1007/s00216-009-3159-0
M3 - Article
C2 - 19795108
AN - SCOPUS:71449120192
SN - 0016-1152
VL - 395
SP - 2559
EP - 2567
JO - Fresenius Zeitschrift fur Analytische Chemie
JF - Fresenius Zeitschrift fur Analytische Chemie
IS - 8
ER -