Analytical Chemistry Chemical Cytometry Quantitates Superoxide

More documents

Recommendations

Info

Figure 4. SEM images of (a-d) Si samples patterned by printing with (a) NBD/1 M H2SO4, (b)1MH2SO4, (c) ABD/0.5 M HCl, and (d) 0.5 M HCl inks; (e, f) Cu samples patterned by printing with (e) NBD/1 MH2SO4 and(f)1MH2SO4 inks. Table 2. Film Thicknesses for NA Layer Coupled to CP Film and Associated Controls surface film thickness/nm a PPF-CP 1.0 ± 0.3 PPF-CP/SOCl2/NA 2.0 ± 0.5 PPF-CP/NA 1.0 ± 0.4 PPF-H2SO4/SOCl2/NA 0.4 ± 0.2 a AFM line profiles are shown in Figure S-4 (Supporting Information). NA + CP on PPF. CP groups were printed on PPF using nonpatterned stamps and CBD/1 M H2SO4 ink. The films were activated by immersion in SOCl2 for 30 min and then transferred to a 20 mM NA/ACN solution at room temperature for 24 h to promote coupling of NA groups to the CP layer via the formation of amide bonds. These samples are denoted PPF-CP/ SOCl2/NA. Controls were also prepared: PPF-CP blanks were obtained by printing CP films onto PPF without subsequent activation or immersion in NA/ACN; for PPF-CP/NA blanks, only the activation step was omitted; and for PPF-H2SO4/ SOCl2/NA, blanks were prepared by printing PPF with blank 1MH2SO4, followed by “activation” and immersion in NA/ ACN. Prior to their analysis, all samples and controls were sonicated for 5 min in ACN. AFM depth profiling results are shown in Table 2, and cyclic voltammograms of the modified surfaces and typical AFM line profiles are shown in Figures S-3 and S-4 (Supporting Information). Activation of the CP film and reaction with NA increased the film thickness from 1.0 ± 0.3 to 2.0 ± 0.5 nm, consistent with the coupling of NA groups to the CP layer. When the activation step 7032 Analytical Chemistry, Vol. 82, No. 16, August 15, 2010 Figure 5. AFM image of VACNTs tethered to a patterned AP layer on PPF. was omitted, there was no change in film thickness, confirming that NA does not physisorb to the CP film. Interestingly, a thin surface layer of NA was detected electrochemically (Figure S-3, Supporting Information) and by AFM measurements on the PPF-H2SO4/SOCl2/NA controls. The measured thickness (0.4 ± 0.2 nm) of this film is less than expected for a monolayer of NA groups (0.8 nm), indicating a submonolayer coverage. We assume that NA couples directly to a low concentration of carboxylate functionalities on the (otherwise) bare PPF surface. SWCNT + AP on PPF. This second example of the utility of printed films as tethers is based on recent work in which we assembled and characterized vertically aligned carbon nanotube (VACNT) forests on AP films electrografted to PPF. 46 To test whether printed AP films could be used similarly, PPF surfaces were patterned using ABD/0.5 M HCl ink and then immersed in a DMSO solution (2 mL) of cut SWCNTs (0.2 mg mL -1 ) and N,N′dicyclohexylcarbodiimide (1 mg mL -1 )for24hat65°C. These conditions promote formation of amide bonds between surfaceimmobilized AP groups and carboxylate groups at the cut ends of the SWCNTs. The resultant surfaces were sonicated in acetone for 10 s and then in isopropyl alcohol for 10 s prior to imaging by AFM. The image shown in Figure 5 (and the SEM image in Figure S-5, Supporting Information) is similar to those previously obtained for VACNTs on electrografted AP tether layers. 46 These examples demonstrate that MCP yields tether layers with their usual reactivity, and hence, the method can be used to prepare patterned substrates which form the basis of more complex structures. Buildup MCP Patterning of Two-Component Surfaces. Two- or multicomponent films in which secondary modifiers are patterned on top of a continuous base film have potential applications in sensing, where (for example) the base film is tailored to reduce nonspecific interactions with the analyte while the patterned secondary modifiers act either as tethers for attachment of recognition species or as the recognition elements themselves. This “buildup” method relies on the ability of the substrate to reduce the secondary modifiers by electron transfer across the base film. Reduction of the printed secondary modifier generates radicals which couple to the base film. Hence, a covalently coupled structure spontaneously forms in a single, simple step requiring no additional reagents. The buildup method (46) Garrett, D. J.; Flavel, B. S.; Shapter, J. G.; Baronian, K. H. R.; Downard, A. J. Langmuir 2010, 26, 1848–1854.
Table 3. Film Thickness Measurements on PPF Substrates Modified with CP Films with and without Overprinting of a NP Layer a film thickness/nm b sonication solvent and time CP region CP/NP region H2O (5 min) 1.6 ± 0.3 2.2 ± 0.3 H2O (5 min) 1.4 ± 0.3 2.1 ± 0.2 H2O (5 min) + ACN (30 min) 1.7 ± 0.6 2.1 ± 0.3 H2O (5 min) + ACN (30 min) 1.5 ± 0.4 2.0 ± 0.2 a Samples were prepared in duplicate. b AFM line profiles are shown in Figure S-7 (Supporting Information). Figure 6. SEM images of surfaces that were immersed in 10 mM CBD/0.1 H2SO4 for 30 min and subsequently printed with (a) ABD/ 0.5 M HCl and (b) 0.5 M HCl inks. After printing, the surfaces were immersed in Au nanoparticle solution for 40 min. was demonstrated by printing the secondary modifiers NP and AP. CP + NP on PPF. NP groups were printed onto a base CP film grafted spontaneously to PPF at OCP. Two ∼3.0 × 1.5 mm 2 PPF samples were immersed in 10 mM CBD/0.1 M H2SO4 solution for 30 min to form the base films. One half of each sample was then printed with a nonpatterned stamp using NBD/1 M H2SO4 ink. Cyclic voltammetry (Figure S-6, Supporting Information) confirmed that NBD had reacted in the expected manner giving an NP layer. AFM depth profiling measurements of printed and unprinted sections (Table 3) show that printing increases the film thickness, consistent with attachment of NP to the CP layer. The magnitude of the increase (∼0.4-0.7 nm) corresponds to the addition of a submonolayer of NP groups on top of the CP film. However, NP is also expected to couple within the CP film, and hence, the concentration of printed NP groups may be higher than indicated by film thickness data. To test the stability of the printed layers, the samples were sonicated in ACN for 30 min and the AFM measurements were repeated. The data in the lower part of Table 3 indicate that the film thicknesses did not change significantly, consistent with covalent attachment both to the substrate surface and between the base and printed layers. CP + AP on PPF. In the second example of the buildup printing approach, AP groups were patterned onto a spontaneously grafted layer of CP groups using a patterned stamp with ABD/ 0.5 M HCl ink. A blank was also prepared on a CP layer by printing with blank 0.5 M HCl ink. The printed surfaces were immersed for 40 min in a solution of Au nanoparticles and then sonicated in H 2O for 30 s prior to analysis by SEM. Figure 6 shows the SEM images where the assembled Au nanoparticles clearly reveal the patterned immobilization of AP (Figure 6a) in comparison with the control (Figure 6b). The buildup approach for preparing patterned two- or multicomponent surfaces should be applicable to all substrates at which grafting from aryldiazonium salt solutions proceeds spontaneously at OCP. However, the requirement that the second aryldiazonium cation be reduced by the substrate places some limitations on the nature and thickness of the base film and also on the aryldiazonium cation derivative. For strongly reducing substrates (such as zinc), it should be possible to print even relatively difficultto-reduce aryldiazonium cations onto thick base films. On the other hand, printing on less-reducing substrates (such as Au) is likely to be successful only with easily reduced aryldiazonium salt derivatives on thin base films. In the examples above, the base films were formed by spontaneous grafting from a aryldiazonium salt solution. There is no reason why MCP, electrografting, and/ or other classes of modifiers cannot be used. Methods such as electro-oxidation of primary amines 47 or arylhydrazines; 48 electroreduction of iodonium, 49,50 sulfonium 51 salts, or vinylic compounds; 52 photolytic or thermal grafting of alkenes and alkynes; 53-56 or photografting of arylazides 57 would greatly widen the range of functionalities that could be added to the surface. CONCLUSION Microcontact printing using aryldiazonium salt inks has been applied to carbon, metal, and semiconductor substrates to give stable, covalently attached, thin films. The thickness and the morphology of the printed film appear to depend on the potential driving force for reduction of the aryldiazonium cation by the substrate. Aminophenyl and carboxyphenyl groups in printed layers retain the ability to form amide bonds with solution species and, consequently, provide useful tethers for more complex surface structures. Microcontact printing using aryldiazonium salts is applicable to all substrate-diazonium salt combinations for which surface modification proceeds spontaneously at open circuit potential in solution. The variable film thickness and roughness, which is substrate- and film-dependent, may be a limitation for some potential applications; however, compared with other methods for patterning layers using aryldiazonium salts, microcontact is low cost and simple to implement with no requirement for electrochemical capability. Tightly defined patterns with feature sizes tens of micrometers upward can be routinely prepared, and (47) Barbier, B.; Pinson, J.; Desarmot, G.; Sanchez, M. J. Electrochem. Soc. 1990, 137, 1757–1764. (48) Malmos, K.; Iruthayaraj, J.; Pedersen, S. U.; Daasbjerg, K. J. Am. Chem. Soc. 2009, 131, 13926–13927. (49) Vase, K. H.; Holm, A. H.; Norrman, K.; Pedersen, S. U.; Daasbjerg, K. Langmuir 2007, 23, 3786–3793. (50) Vase, K. H. j.; Holm, A. H. k.; Pedersen, S. U.; Daasbjerg, K. Langmuir 2005, 21, 8085–8089. (51) Vase, K. H.; Holm, A. H.; Norrman, K.; Pedersen, S. U.; Daasbjerg, K. Langmuir 2008, 24, 182–188. (52) Palacin, S.; Bureau, C.; Charlier, J.; Deniau, G.; Mouanda, B.; Viel, P. ChemPhysChem 2004, 5, 1469–1481. (53) Lasseter, T. L.; Cai, W.; Hamers, R. J. Analyst 2004, 129, 3–8. (54) Ssenyange, S.; Anariba, F.; Bocian, D. F.; McCreery, R. L. Langmuir 2005, 21, 11105–11112. (55) Sun, B.; Colavita, P. E.; Kim, H.; Lockett, M.; Marcus, M. S.; Smith, L. M.; Hamers, R. J. Langmuir 2006, 22, 9598–9605. (56) Yu, S. S. C.; Downard, A. J. Langmuir 2007, 23, 4662–4668. (57) Gross, A. J.; Yu, S. S. C.; Downard, A. J. Langmuir 2010, 26, 7285–7292. Analytical Chemistry, Vol. 82, No. 16, August 15, 2010 7033
Page 1 and 2:
Anal. Chem. 2010, 82, 6745-6750 Let
Page 3 and 4:
purchased from Invitrogen-Molecular
Page 5 and 6:
Figure 3. Electropherograms of TPP-
Page 7 and 8:
Anal. Chem. 2010, 82, 6751-6755 Res
Page 9 and 10:
(pH 8.0) with cysteine and cystamin
Page 11 and 12:
Figure 4. Ion mobility mass spectra
Page 13 and 14:
GOx glucose + O298 gluconic acid +
Page 15 and 16:
coater at 2000 rpm for 20 s, and th
Page 17 and 18:
Figure 5. Comparison of cyclic volt
Page 19 and 20:
in channels with either no grooves
Page 21 and 22:
indicators of atmospheric processin
Page 23 and 24:
Figure 1. GC/MS total ion chromatog
Page 25 and 26:
Table 2. Concentrations and Stable
Page 27 and 28:
on a substrate are preferred. 20-24
Page 29 and 30:
Figure 4. SERS analysis of NAADP co
Page 31 and 32:
Anal. Chem. 2010, 82, 6775-6781 Hig
Page 33 and 34:
tion, 2 µL of proprionaldehyde wer
Page 35 and 36:
Figure 4. Analysis of 2a by HPLC-MS
Page 37 and 38:
eaction of 1a with PBH can be condu
Page 39 and 40:
Numerous references had demonstrate
Page 41 and 42:
Figure 1. TEM images of the prepare
Page 43 and 44:
Figure 4. Schematic representation
Page 45 and 46:
esult in a big SPR signal change wi
Page 47 and 48:
also reduces chemical noise, which
Page 49 and 50:
Table 1. Extraction Yields, Liquid
Page 51 and 52:
scanning of AMPP amides of the anal
Page 53 and 54:
Anal. Chem. 2010, 82, 6797-6806 δ
Page 55 and 56:
Figure 1. Schematic view of the pre
Page 57 and 58:
from the specimen and enclosed in a
Page 59 and 60:
Figure 4. (A) IRMS mass-44 chromato
Page 61 and 62:
Table 3. Ambient Measurement Result
Page 63 and 64:
Anal. Chem. 2010, 82, 6807-6813 Dir
Page 65 and 66:
Polymerase (1 U per sample). Reacti
Page 67 and 68:
of which was constant for all ampli
Page 69 and 70:
analytically useful signals at less
Page 71 and 72:
carbon black and RP-C18 for the ext
Page 73 and 74:
solution in an equal volume, and 1
Page 75 and 76:
Table 2. Concentrations and Ratios
Page 77 and 78:
Anal. Chem. 2010, 82, 6821-6829 Mac
Page 79 and 80:
mg/mL protein, followed by separati
Page 81 and 82:
Figure 2. Productivity of SEQUST an
Page 83 and 84:
Figure 4. High-resolution MS/MS spe
Page 85 and 86:
Figure 6. Characterization of PSMs
Page 87 and 88:
containing T-T mismatches. 23 Based
Page 89 and 90:
Figure 1. Extinction spectra of sol
Page 91 and 92:
Figure 3. (A) The value of Ex650 nm
Page 93 and 94:
Figure 5. Extinction spectra and co
Page 95 and 96:
wished to explore the dehydration o
Page 97 and 98:
constant medium for separation; we
Page 99 and 100:
Figure 2. Standards of (Pi)n, n ) 1
Page 101 and 102:
Figure 5. Quantitative calibration
Page 103 and 104:
Anal. Chem. 2010, 82, 6847-6853 Met
Page 105 and 106:
Figure 1. 226 Ra spectrum by liquid
Page 107 and 108:
Table 1. Counting Properties and De
Page 109 and 110:
Table 3. Analysis of 226 Ra in Sedi
Page 111 and 112:
mercial microarray scanner and fabr
Page 113 and 114:
Figure 2. Optical transmission meas
Page 115 and 116:
Figure 5. Volcano plots detailing t
Page 117 and 118:
data as well. The 41 genes in Table
Page 119 and 120:
corresponding compound if its chemi
Page 121 and 122:
Figure 1. Schematic illustration of
Page 123 and 124:
Table 1. Absolute Quantification Re
Page 125 and 126:
ment. Therefore, the long-time drea
Page 127 and 128:
Figure 1. Chemically actuated micro
Page 129 and 130:
Figure 2. Influence of a surfactant
Page 131 and 132:
Figure 5. Device to eject and mix s
Page 133 and 134:
Anal. Chem. 2010, 82, 6877-6886 Imm
Page 135 and 136:
NaCl, phosphate buffer saline (PBS)
Page 137 and 138:
Figure 2. Product ion mass spectra
Page 139 and 140:
-70 °C resolved the problem, givin
Page 141 and 142:
Table 1. Intraday Precision and Acc
Page 143 and 144:
Anal. Chem. 2010, 82, 6887-6894 Fer
Page 145 and 146:
Figure 1. Infrared spectra of (A) u
Page 147 and 148:
Figure 3. Cyclic voltammograms obta
Page 149 and 150:
Figure 6. Calculated charge from ch
Page 151 and 152:
Anal. Chem. 2010, 82, 6895-6903 Ele
Page 153 and 154:
Table 1. Chemical Structure, pKa Va
Page 155 and 156:
pH with a tilted baseline (Figure 1
Page 157 and 158:
Table 2. Linearity and Detection Li
Page 159 and 160:
ascorbic acid (AA), uric acid (UA),
Page 161 and 162:
the multielement capabilities, the
Page 163 and 164:
RESULTS AND DISCUSSION Sulfur Detec
Page 165 and 166:
Table 2. Molecular Properties and C
Page 167 and 168:
Anal. Chem. 2010, 82, 6911-6918 Dir
Page 169 and 170:
dilution and hybridization buffer.
Page 171 and 172:
solution under appropriate incubati
Page 173 and 174:
Figure 4. Standardization curve for
Page 175 and 176:
Anal. Chem. 2010, 82, 6919-6925 Ele
Page 177 and 178:
the ×10 objective, to have a large
Page 179 and 180:
Figure 2. With a suitable removal o
Page 181 and 182:
the NB signal in a much better foot
Page 183 and 184:
Scheme 1. Reactions of Selenium Rea
Page 185 and 186:
Figure 2. (a) ESI-MS spectrum showi
Page 187 and 188:
Figure 4. (a) ESI-MS spectrum showi
Page 189 and 190:
Anal. Chem. 2010, 82, 6933-6939 Dif
Page 191 and 192:
trode 28 by a finite element using
Page 193 and 194:
Figure 4. Comparison between simula
Page 195 and 196:
Figure 6. Comparison between simula
Page 197 and 198:
educed in the vicinity of double bo
Page 199 and 200:
Figure 2. Normalized product ion ab
Page 201 and 202:
Figure 4. EID (a) and IRMPD (b) of
Page 203 and 204:
Anal. Chem. 2010, 82, 6947-6957 Ide
Page 205 and 206:
Figure 1. Schematic flowchart showi
Page 207 and 208:
difference, ppm compound Table 1. I
Page 209 and 210:
isoforms, its successful use, in th
Page 211 and 212:
Figure 5. Extracted ion current ESI
Page 213 and 214:
m/z 1172.935 was observed for Ser14
Page 215 and 216:
linked products via affinity tags.
Page 217 and 218:
Scheme 2. Fragmentation Mechanism o
Page 219 and 220:
Figure 1. (A) ESI-LTQ-CID-MS 2 prod
Page 221 and 222:
Figure 3. (A) ESI-LTQ-CID-MS 2 prod
Page 223 and 224:
Figure 5. (A) MALDI-TOF/TOF product
Page 225 and 226:
Anal. Chem. 2010, 82, 6969-6975 Ana
Page 227 and 228:
Figure 3. Equilibrium response as a
Page 229 and 230:
Figure 6. The average measured resp
Page 231 and 232:
for the fill time, and we find that
Page 233 and 234:
nucleotide tails. 3-5 Thus, the amo
Page 235 and 236:
allow the use of higher aptamer con
Page 237 and 238: quent ligation of the aptamers afte
Page 239 and 240: Anal. Chem. 2010, 82, 6983-6990 Imp
Page 241 and 242: Figure 2. Configuration editor wind
Page 243 and 244: Figure 4. Dependencies between volu
Page 245 and 246: Since the time for liquid expulsion
Page 247 and 248: Anal. Chem. 2010, 82, 6991-6999 Int
Page 249 and 250: Figure 1. Representation of the Car
Page 251 and 252: Table 2. Capillary Electrophoresis
Page 253 and 254: Figure 4. (A) Typical raw electroph
Page 255 and 256: field. DNA profiles were delivered
Page 257 and 258: Another approach to handle this lim
Page 259 and 260: (principal components, PCs) in whic
Page 261 and 262: Figure 5. Relevant score plots and
Page 263 and 264: CONCLUSIONS In this paper we have i
Page 265 and 266: electroactive-species loaded liposo
Page 267 and 268: Figure 2. Qdot-based FLFTS response
Page 269 and 270: Figure 6. Fluorescence imaging of Q
Page 271 and 272: Anal. Chem. 2010, 82, 7015-7020 Sel
Page 273 and 274: Table 1. Effect of 1 D-LC Condition
Page 275 and 276: Figure 3. Peak-production rate vers
Page 277 and 278: Anal. Chem. 2010, 82, 7021-7026 Cel
Page 279 and 280: luciferase (T7 control vector) was
Page 281 and 282: Figure 3. Inhibitory effects of luc
Page 283 and 284: Anal. Chem. 2010, 82, 7027-7034 Pat
Page 285 and 286: Electrochemistry. Electrochemical m
Page 287: Figure 2. SEM images of Au substrat
Page 291 and 292: Anal. Chem. 2010, 82, 7035-7043 Qua
Page 293 and 294: Figure 1. (A) FL spectra of BSPOTPE
Page 295 and 296: Figure 4. (A) Variation in the FL i
Page 297 and 298: Figure 6. (A) FL spectra of BSPOTPE
Page 299 and 300: Scheme 1. Proposed Mechanism for Fl
Page 301 and 302: one or more drawbacks including poo
Page 303 and 304: Figure 2. Free fluorophores do not
Page 305 and 306: Anal. Chem. 2010, 82, 7049-7052 Dev
Page 307 and 308: Figure 2. Comparative analysis of d
show all

Analytical Chemistry Chemical Cytometry Quantitates Superoxide

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?