TY - JOUR
T1 - Synthesis of fluorescent carbohydrate-protected Au nanodots for detection of Concanavalin A and Escherichia coli
AU - Huang, Chih Ching
AU - Chen, Chao Tsen
AU - Shiang, Yen Chun
AU - Lin, Zong Hong
AU - Chang, Huan Tsung
PY - 2009/2/1
Y1 - 2009/2/1
N2 - This study describes a novel, simple, and convenient method for the preparation of water-soluble biofunctional Au nanodots (Au NDs) for the detection of Concanavalin A (Con A) and Escherichia coli (E. coli). First, 2.9 nm Au nanoparticles (Au NPs) were prepared through reduction of HAuCl 4 3H2O with tetrakis(hydroxymethyl)phosphonium chloride (THPC), which acts as both a reducing and capping agent. Addition of 11-mercapto-3,6,9-trioxaundecyl-α-D-mannopyranoside (Man-SH) onto the surfaces of the as-prepared Au NPs yielded the fluorescent mannose-protected Au nanodots (Man-Au NDs) with the size and quantum yield (QY) of 1.8 (±0.3) nm and 8.6%, respectively. This QY is higher than those of the best currently available water-soluble, alkanethiol-protected Au nanoclusters. Our fluorescent Man-Au NDs are easily purified and by multivalent interactions are capable of sensing, under optimal conditions, Con A with high sensitivity (LOD = 75 pM) and remarkable selectivity over other proteins and lectins. To the best of our knowledge, this approach provided the lowest LOD value for Con A when compared to the other nanomaterials-based detecting method. Furthermore, we have also developed a new method for fluorescence detection of E. coli using these water-soluble Man-Au NDs. Incubation with E. coli revealed that the Man-Au NDs bind to the bacteria, yielding brightly fluorescent cell clusters. The relationship between the fluorescence signal and the E. coli concentration was linear from 1.00 × 106 to 5.00 × 107 cells/mL (R2 = 0.96), with the LOD of E. coli being 7.20 × 10 5 cells/mL.
AB - This study describes a novel, simple, and convenient method for the preparation of water-soluble biofunctional Au nanodots (Au NDs) for the detection of Concanavalin A (Con A) and Escherichia coli (E. coli). First, 2.9 nm Au nanoparticles (Au NPs) were prepared through reduction of HAuCl 4 3H2O with tetrakis(hydroxymethyl)phosphonium chloride (THPC), which acts as both a reducing and capping agent. Addition of 11-mercapto-3,6,9-trioxaundecyl-α-D-mannopyranoside (Man-SH) onto the surfaces of the as-prepared Au NPs yielded the fluorescent mannose-protected Au nanodots (Man-Au NDs) with the size and quantum yield (QY) of 1.8 (±0.3) nm and 8.6%, respectively. This QY is higher than those of the best currently available water-soluble, alkanethiol-protected Au nanoclusters. Our fluorescent Man-Au NDs are easily purified and by multivalent interactions are capable of sensing, under optimal conditions, Con A with high sensitivity (LOD = 75 pM) and remarkable selectivity over other proteins and lectins. To the best of our knowledge, this approach provided the lowest LOD value for Con A when compared to the other nanomaterials-based detecting method. Furthermore, we have also developed a new method for fluorescence detection of E. coli using these water-soluble Man-Au NDs. Incubation with E. coli revealed that the Man-Au NDs bind to the bacteria, yielding brightly fluorescent cell clusters. The relationship between the fluorescence signal and the E. coli concentration was linear from 1.00 × 106 to 5.00 × 107 cells/mL (R2 = 0.96), with the LOD of E. coli being 7.20 × 10 5 cells/mL.
UR - http://www.scopus.com/inward/record.url?scp=61449147073&partnerID=8YFLogxK
U2 - 10.1021/ac8010654
DO - 10.1021/ac8010654
M3 - 文章
C2 - 19119843
AN - SCOPUS:61449147073
SN - 0003-2700
VL - 81
SP - 875
EP - 882
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 3
ER -