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1.
Quantum dots (QDs) are inorganic semiconductor nanocrystals that have unique optoelectronic properties responsible for bringing
together multidisciplinary research to impel their potential bioanalytical applications. In recent years, the many remarkable
optical properties of QDs have been combined with the ability to make them increasingly biocompatible and specific to the
target. With this great development, QDs hold particular promise as the next generation of fluorescent probes. This review
describes the developments in functionalizing QDs making use of different bioconjugation and capping approaches. The progress
offered by QDs is evidenced by examples on QD-based biosensing, biolabeling, and delivery of therapeutic agents. In the near
future, QD technology still faces some challenges towards the envisioned broad bioanalytical purposes.
相似文献
2.
Xiaoshan Zhu Dayue Duan Steen Madsen Nelson G. Publicover 《Analytical and bioanalytical chemistry》2010,396(3):1345-1353
In this work, the compatibility of quantum dots (QDs) with immunobuffers was studied by investigating the fluorescence stability
of QDs in immunobuffers (in this research immunobuffers were defined as buffers for immunoaffinity binding or separation).
Experimentally, the fluorescence signals of QDs with different surface chemistries (amine-terminated, streptavidin-coated,
or antibody-conjugated) in commonly used immunobuffers were monitored versus time. The effect of some buffer composition on
the compatibility of QDs with these buffers was also explored. Based on experimental data, the QD compatibility with these
buffers is summarized, and it is found that a trace amount of bovine serum albumin added to most of these buffers helps QDs
to achieve compatibility with them. Moreover, with QD as fluorescence label and C-reactive protein as a model analyte, a magnetic
bead-based assay was performed using compatible and incompatible QD–immunobuffer systems. It is shown that compatible QD–immunobuffer
systems can be used to achieve a higher assay signal/background ratio.
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3.
Dana Cialla Ronald Siebert Uwe Hübner Robert Möller Henrik Schneidewind Roland Mattheis Jörg Petschulat Andreas Tünnermann Thomas Pertsch Benjamin Dietzek Jürgen Popp 《Analytical and bioanalytical chemistry》2009,394(7):1811-1818
Surface-enhanced Raman scattering (SERS) is a potent tool in bioanalytical science because the technique combines high sensitivity
with molecular specificity. However, the widespread and routine use of SERS in quantitative biomedical diagnostics is limited
by tight requirements on the reproducibility of the noble metal substrates used. To solve this problem, we recently introduced
a novel approach to reproducible SERS substrates. In this contribution, we apply ultrafast time-resolved spectroscopy to investigate
the photo-induced collective charge-carrier dynamics in such substrates, which represents the fundamental origin of the SERS
mechanism. The ultrafast experiments are accompanied by scanning-near field optical microscopy and SERS experiments to correlate
the appearance of plasmon dynamics with the resultant evanescent field distribution and the analytically relevant SERS enhancement.
Figure Ultrafast time-resolved differential absorption spectroscopy combined with scanning near-field optical microscopy (left) and
atomic force microscopy (right) yields insight into the photoinduced charge-carrier dynamics in innovative reproducible SERS-substrates
Dana Cialla and Ronald Siebert contributed equally to this work. 相似文献
4.
Willard DM Mutschler T Yu M Jung J Van Orden A 《Analytical and bioanalytical chemistry》2006,384(3):564-571
Nanoscale sensors can be created when an expected energetic pathway is created and then that pathway is either initiated or
disrupted by a specific binding event. Constructing the sensor on the nanoscale could lead to greater sensitivity and lower
limits of detection. To this end, quantum dots (QDs) can be considered prime candidates for the active components. Relative
to organic chromophores, QDs have tunable spectral properties, show less susceptibility to photobleaching, have similar brightness,
and have been shown to display electro-optical properties. In this review, we discuss recent articles that incorporate QDs
into directed energy flow systems, some with the goal of building new and more powerful sensors and others that could lead
to more powerful sensors.
Figure 相似文献
5.
Raman spectroscopy on transition metals 总被引:2,自引:0,他引:2
Surface-enhanced Raman spectroscopy (SERS) has developed into one of the most important tools in analytical and surface sciences
since its discovery in the mid-1970s. Recent work on the SERS of transition metals concluded that transition metals, other
than Cu, Ag, and Au, can also generate surface enhancement as high as 4 orders of magnitude. The present article gives an
overview of recent progresses in the field of Raman spectroscopy on transition metals, including experimental, theory, and
applications. Experimental considerations of how to optimize the experimental conditions and calculate the surface enhancement
factor are discussed first, followed by a very brief introduction of preparation of SERS-active transition metal substrates,
including massive transition metal surfaces, aluminum-supported transition metal electrodes, and pure transition metal nanoparticle
assembled electrodes. The advantages of using SERS in investigating surface bonding and reaction are illustrated for the adsorption
and reaction of benzene on Pt and Rh electrodes. The electromagnetic enhancement, mainly lightning-rod effect, plays an essential
role in the SERS of transition metals, and that the charge-transfer effect is also operative in some specific metal–molecule
systems. An outlook for the field of Raman spectroscopy of transition metals is given in the last section, including the preparation
of well-ordered or well-defined nanostructures, and core-shell nanoparticles for investigating species with extremely weak
SERS signals, as well as some new emerging techniques, including tip-enhanced Raman spectroscopy and an in situ measuring
technique.
Figure Electric-field enhancement of a SERS-active Rh surface decorated with small nanohemispheres 相似文献
6.
Hua XF Liu TC Cao YC Liu B Wang HQ Wang JH Huang ZL Zhao YD 《Analytical and bioanalytical chemistry》2006,386(6):1665-1671
Water-soluble quantum dots (QDs) were used to label goat anti-human immunoglobulin antibodies (Abs), and the labeling process
was characterized by column purification. The QDs obtained in organic solvent were modified with mercaptoacetic acid (MAA)
and became water-soluble. These water-soluble QDs were linked to the antibodies using the coupling reagents ethyl-3-(dimethyl
aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The linking process was shown to be effective by ultra-filter centrifugation and column purification.
After comparing the quantities of Abs and water-soluble QDs involved in the linking reaction via column purification, it was
found that a molar Abs:QD ratio of >1.2 resulted in most of the water-soluble QDs becoming covalently linked to the Abs. The
circular dichroism (CD) spectra of Abs and QD–Ab conjugates were very similar to each other, indicating that the secondary
structure of Abs remained largely intact after the conjugation. Finally, antigen (Ag)–antibody (Ab) recognition reactions
perfomed on the surface of a glass slide showed that the conjugate retained the activity of Abs. This work lends support to
the idea of linking biomolecules to QDs, and thus should aid the application of QDs to the life sciences.
Figure Firstly in this work, the conjugates of QDs-Ab were separated from EDC&NHS in the column of Sephadex G-100(left up). Then
the bioactivity of QDs-Ab was analyzed in the immunoassay (right) and the immunofluorescent signals were detected (left bottom)
finally 相似文献
7.
Surface-enhanced Raman scattering for protein detection 总被引:1,自引:0,他引:1
Proteins are essential components of organisms and they participate in every process within cells. The key characteristic
of proteins that allows their diverse functions is their ability to bind other molecules specifically and tightly. With the
development of proteomics, exploring high-efficiency detection methods for large-scale proteins is increasingly important.
In recent years, rapid development of surface-enhanced Raman scattering (SERS)-based biosensors leads to the SERS realm of
applications from chemical analysis to nanostructure characterization and biomedical applications. For proteins, early studies
focused on investigating SERS spectra of individual proteins, and the successful design of nanoparticle probes has promoted
great progress of SERS-based immunoassays. In this review we outline the development of SERS-based methods for proteins with
particular focus on our proposed protein-mediated SERS-active substrates and their applications in label-free and Raman dye-labeled
protein detection.
Figure Protein-mediated SERS-active substrates for protein detection 相似文献
8.
Liming Wang Yu-Feng Li Liangjun Zhou Ying Liu Li Meng Ke Zhang Xiaochun Wu Lili Zhang Bai Li Chunying Chen 《Analytical and bioanalytical chemistry》2010,396(3):1105-1114
Integrated analytical techniques were used to study the tissue distribution and structural information of gold nanorods (Au
NRs) in Sprague-Dawley rats through tail intravenous injection. Before in vivo experiments were conducted, careful characterization
of Au NRs was performed. The zeta potential proved that adsorption of bovine serum albumin on Au NRs turned the surface charges
from positive to negative as in an in vitro simulation. The biodistribution of Au NRs was investigated quantitatively by inductively
coupled plasma mass spectrometry at different time points after injection. As target tissues, both liver and spleen were chosen
to further demonstrate the intracellular localization of Au NRs by the combination of transmission electron microscopy and
energy-dispersive X-ray spectroscopy. Moreover, synchrotron-radiation-based X-ray absorption spectroscopy was employed and
it was observed that long-term retention of Au NRs in liver and spleen did not induce obvious changes in the oxidation states
of gold. Therefore, the present systematic method can provide important information about the fates of Au NRs in vivo and
can also be extended to study the biological effects of other metallic nanomaterials in the future.
相似文献
9.
Wang JH Wang HQ Zhang HL Li XQ Hua XF Cao YC Huang ZL Zhao YD 《Analytical and bioanalytical chemistry》2007,388(4):969-974
CdTe quantum dots (QDs) were synthesized in aqueous solution with 3-mercaptopropionic acid as the stabilizer. Chemically reduced
bovine serum albumin (BSA) was used to modify the surface of the QDs. Experimental results showed that the denatured BSA (dBSA)
could be effectively conjugated to the surface of CdTe QDs. Column chromatography was used to purify the conjugates and determine
the optimal ratio of dBSA to QDs. Further experimental results showed that the conjugation of QDs by dBSA efficiently improved
the photoluminescence quantum yield, the chemical stability of QDs and their stability against photobleaching. A facile and
sensitive method for determination of silver(I) ions was proposed based on the fluorescence quenching of the dBSA–QDs. Under
the optimal conditions, the relative fluorescence intensity decreased linearly with the concentration of the silver(I) ions
in the range 0.08–10.66 μM. The detection limit was 0.01 μM. This study provides a new method for the detection of metal cations.
Figure In this work, denatured BSA was used to modify the surface of CdTe QDs by a simple and rapid method. And the conjugates of
dBSA-QDs were purified by column of Sephadex G-100. After the purification of the conjugates, the sensitivity was greatly
increased as silver (I) ions probe. 相似文献
10.
Quantum dots as donors in fluorescence resonance energy transfer for the bioanalysis of nucleic acids,proteins, and other biological molecules 总被引:1,自引:0,他引:1
Quantum dots (QDs) have a number of unique optical properties that are advantageous in the development of bioanalyses based on fluorescence resonance energy transfer (FRET). Researchers have used QDs as energy donors in FRET schemes for the analysis of nucleic acids, proteins, proteases, haptens, and other small molecules. This paper reviews these applications of QDs. Existing FRET technologies can potentially be improved by using QDs as energy donors instead of conventional fluorophores. Superior brightness, resistance to photobleaching, greater optimization of FRET efficiency, and/or simplified multiplexing are possible with QD donors. The applicability of the Förster formalism to QDs and the feasibility of using QDs as energy acceptors are also reviewed. 相似文献
11.
A. Hartschuh H. Qian C. Georgi M. Böhmler L. Novotny 《Analytical and bioanalytical chemistry》2009,394(7):1787-1795
We review recent experimental studies on single-walled carbon nanotubes on substrates using tip-enhanced near-field optical
microscopy (TENOM). High-resolution optical and topographic imaging with sub 15 nm spatial resolution is shown to provide
novel insights into the spectroscopic properties of these nanoscale materials. In the case of semiconducting nanotubes, the
simultaneous observation of Raman scattering and photoluminescence (PL) is possible, enabling a direct correlation between
vibrational and electronic properties on the nanoscale. So far, applications of TENOM have focused on the spectroscopy of
localized phonon modes, local band energy renormalizations induced by charge carrier doping, the environmental sensitivity
of nanotube PL, and inter-nanotube energy transfer. At the end of this review we discuss the remaining limitations and challenges
in this field.
Figure Tip-enhanced Raman scattering and photoluminescence spectroscopy with sub 15 nm spatial resolution provides novel insights
into the electronic and vibronic properties of single-walled carbon nanotubes. 相似文献
12.
Surface plasmon resonance (SPR) is a powerful and versatile spectroscopic method for biomolecular interaction analysis (BIA)
and has been well reviewed in previous years. This updated 2006 review of SPR, SPR spectroscopy, and SPR imaging explores
cutting-edge technology with a focus on material, method, and instrument development. A number of recent SPR developments
and interesting applications for bioanalysis are provided. Three focus topics are discussed in more detail to exemplify recent
progress. They include surface plasmon fluorescence spectroscopy, nanoscale glassification of SPR substrates, and enzymatic
amplification in SPR imaging. Through these examples it is clear to us that the development of SPR-based methods continues
to grow, while the applications continue to diversify. Major trends appear to be present in the development of combined techniques,
use of new materials, and development of new methodologies. Together, these works constitute a major thrust that could eventually
make SPR a common tool for surface interaction analysis and biosensing. The future outlook for SPR and SPR-associated BIA
studies, in our opinion, is very bright.
Surface plasmon resonance (SPR) is a powerful and versatile spectroscopic method for biomolecular interaction analysis (BIA)
and has been well reviewed in previous years. This updated 2006 review of SPR, SPR spectroscopy, and SPR imaging explores
cutting-edge technology with a focus on material, method, and instrument development. A number of recent SPR developments
and interesting applications for bioanalysis are provided. Three focus topics are discussed in more detail to exemplify recent
progress. They include surface plasmon fluorescence spectroscopy, nanoscale glassification of SPR substrates, and enzymatic
amplification in SPR imaging. Through these examples it is clear to us that the development of SPR-based methods continues
to grow, while the applications continue to diversify. Major trends appear to be present in the development of combined techniques,
use of new materials, and development of new methodologies. Together, these works constitute a major thrust that could eventually
make SPR a common tool for surface interaction analysis and biosensing. The future outlook for SPR and SPR-associated BIA
studies, in our opinion, is very bright.
相似文献
13.
Fourier transform infrared (FTIR) spectroscopic imaging is a relatively new method that has received great attention as a
new field of analytical chemistry. The greatest benefit of this technique lies in the high molecular sensitivity combined
with a spatial resolution down to a few micrometers. Another advantage is the ability to probe samples under native conditions,
which allows new insights into samples without the need for fixation, stains, or an additional marker. Advances in instrumentation
have made FTIR spectroscopic imaging the tool of choice for an increasing number of applications. The main applications are
in the bioanalytical chemistry of cells and tissue, polymers, and recently as well as in homeland security. This report gives
a short overview of current developments and recent applications.
Figure FTIR image of a polymer blend reveals the chemical composition. Online Abstract Figure (365 KB). 相似文献
14.
Schaffer B Grogger W Kothleitner G Hofer F 《Analytical and bioanalytical chemistry》2008,390(6):1439-1445
In this work we show how energy-filtered imaging can be used to obtain spectrum images of electron energy-loss spectrometric
data. Focus is placed on improved energy resolution within these data sets. Using two multilayer samples (GaN/AlN and InP/InAs),
we demonstrate the advantages of spectrum-imaging and its extended mapping capabilities. Plasmon-ratio maps are used to quickly
create high-contrast material maps with high signal-to-noise ratio, ratio-contrast plots are used to gain optimum settings
for the ratio maps, and plasmon-position maps are used to map small shifts of the energy position of bulk plasmon peaks.
Figure Scheme of EELS SI and derived plasman-position map 相似文献
15.
QD-Au NP@silica mesoporous microspheres have been fabricated as a novel enzyme-mimic nanosensor. CdTe quantum dots (QDs) were loaded into the core, and Au nanoparticles (NPs) were encapsulated in the outer mesoporous shell. QDs and Au NPs were separated in the different space of the nanosensor, which prevent the potential energy or electron transfer process between QDs and Au NPs. As biomimetic catalyst, Au NPs in the mesoporous silica shell can catalytically oxidize glucose as glucose oxidase (GOx)-mimicking. The resultant hydrogen peroxide can quench the photoluminescence (PL) signal of QDs in the microsphere core. Therefore the nanosensor based on the decrease of the PL intensity of QDs was established for the glucose detection. The linear range for glucose was in the range of 5–200 μM with a detection limit (3σ) of 1.32 μM. 相似文献
16.
Carbon dots (CDs) possess superior fluorescent properties in that they do not blink, are biocompatible, chemically inert, have small size and well tunable photoluminescence (PL), can be easily functionalized with biomolecules, and can be multi-photon excited to give up-converted PL. This review (with 141 refs.) summarizes recent progress in the field of imaging using carbon dots doped with heteroatoms (X-CDs). Following an introduction, we discuss top-down and bottom-up strategies for synthesis and methods for surface modification. We also compare the differences in synthesis for undoped CDs and X-CDs. Specifically, CDs doped with heteroelemets nitrogen, phosphorus, sulfur, selenium, boron and silicium are treated. We then discuss method for determination of the properties (particle size, ZP), how doping affects fluorescence (spectra, quantum yields, decay times), and how dopants affect upconversion (UC, anti-Stokes luminescence). We finally review the progress made in fluorescent imaging of cells tissue, and other biomatter. This review also gives new hints on how to use synthetic methods for tuning the structure of X-CDs, how doping affects properties, and how to achieve new bioimaging applications. 相似文献
17.
Yi-Heui Hsieh Shih-Jen Liu Hsin-Wei Chen Yao-Kwang Lin Keng S. Liang Lee-Jene Lai 《Analytical and bioanalytical chemistry》2010,396(3):1135-1141
This study presents an efficient and sensitive method for detecting rare cells without cell culture, in which cells are analyzed
quantitatively using quantum dots (QDs) as a fluorescent probe. By the conjugation of QDs with cells, the biotin–streptavidin
reaction functions as a bridge to connect QDs and cells. The cells can be quantified based on the correlation of the QD fluorescence
intensity with the cell population. Non-specific adsorption and cross-reaction of QD625–streptavidin on T cell membrane are
neglected by reacting with biotin anti-human CD3 and mixing with red blood cell, respectively. Additionally, the photo-activation
period and pH can be controlled to enhance the fluorescence of cell populations, which increases linearly with the number
of T cells from 40 to 100,000, not only in a single T cell line but also in mixing with a total of 106 red blood cells. Moreover, the specific T cells can be detected in less than 15 min, even though rare specific cells may
number only 40 cells. Among the advantages, the proposed system for detecting rare cells include simplicity of preparation,
low cost, rapid detection, and high sensitivity, all of which can facilitate the detection of circulating tumor cells in early
stages of diagnosis or prognosis.
相似文献
18.
We report the multiplexed, simultaneous analysis of antigen–antibody interactions that involve human immunoglobulin G (IgG)
on a gold substrate by the surface plasmon resonance imaging method. A multichannel, microfluidic chip was fabricated from
poly(dimethylsiloxane) (PDMS) to selectively functionalize the surface and deliver the analyte solutions. The sensing interface
was constructed using avidin as a linker layer between the surface-bound biotinylated bovine serum albumin and biotinylated
anti-human IgG antibodies. Four mouse anti-human IgG antibodies were selected for evaluation and the screening was achieved
by simultaneously monitoring protein–protein interactions under identical conditions. Antibody–antigen binding affinities
towards human immunoglobulin were quantitatively compared by employing Langmuir adsorption isotherms for the analysis of SPRi
responses obtained under equilibrium conditions. We were able to identify two IgG samples with higher affinities towards the
target, and the determined binding kinetics falls within the typical range of values reported in the literature. Direct measurement
of proteins in serum samples by SPR imaging was achieved by developing methods to minimize nonspecific adsorption onto the
avidin-functionalized surface, and a limit of detection (LOD) of 6.7 nM IgG was obtained for the treated serum samples. The
combination of SPR imaging and multichannel PDMS chips offers convenience and flexibility for sensitive and label-free measurement
of protein–protein interactions in complex conditions and enables high-throughput screening of pharmaceutically significant
molecules.
Figure Microchannel SPR imaging for protein–protein interactions 相似文献
19.
Mohammad Kamal Hossain Yasutaka Kitahama Genin Gary Huang Xiaoxia Han Yukihiro Ozaki 《Analytical and bioanalytical chemistry》2009,394(7):1747-1760
Surface-enhanced Raman scattering (SERS) enhancement and the reproducibility of the SERS signal strongly reflect the quality
and nature of the SERS substrates because of diverse localized surface plasmon resonance (LSPR) excitations excited at interstitials
or sharp edges. LSPR excitations are the most important ingredients for achieving huge enhancements in the SERS process. In
this report, we introduce several gold and silver nanoparticle-based SERS-active substrates developed solely by us and use
these substrates to investigate the influence of LSPR excitations on SERS. SERS-active gold substrates were fabricated by
immobilizing colloidal gold nanoparticles on glass slides without using any surfactants or electrolytes, whereas most of the
SERS-active substrates that use colloidal gold/silver nanoparticles are not free of surfactant. Isolated aggregates, chain-like
elongated aggregates and two-dimensional (2D) nanostructures were found to consist mostly of monolayers rather than agglomerations.
With reference to correlated LSPR and SERS, combined experiments were carried out on a single platform at the same spatial
position. The isolated aggregates mostly show a broadened and shifted SPR peak, whereas a weak blue-shifted peak is observed
near 430 nm in addition to broadened peaks centered at 635 and 720 nm in the red spectral region in the chain-like elongated
aggregates. In the case of 2D nanostructures, several SPR peaks are observed in diverse frequency regions. The characteristics
of LSPR and SERS for the same gold nanoaggregates lead to a good correlation between SPR and SERS images. The elongated gold
nanostructures show a higher enhancement of the Raman signal than the the isolated and 2D samples. In the case of SERS-active
silver substrates for protein detection, a new approach has been adopted, in contrast to the conventional fabrication method.
Colloidal silver nanoparticles are immobilized on the protein functionalized glass slides, and further SERS measurements are
carried out based on LSPR excitations. A new strategy for the detection of biomolecules, particularly glutathione, under aqueous
conditions is proposed. Finally, supramolecular J-aggregates of ionic dyes incorporated with silver colloidal aggregates are
characterized by SERS measurements and correlated to finite-difference time-domain analysis with reference to LSPR excitations.
Figure SPR and SERS images for isolated, elongated and two-dimensional gold nanostructures 相似文献
20.
Nagl S Stich MI Schäferling M Wolfbeis OS 《Analytical and bioanalytical chemistry》2009,393(4):1199-1207
Chemical sensing, imaging and microscopy based on the use of fluorescent probes has so far been limited almost exclusively
to the detection of a single parameter at a time. We present a scheme that can overcome this limitation by enabling optical
sensing of two parameter simultaneously and even at identical excitation and emission wavelengths of two probes provided (a)
their decay times are different enough to enable two time windows to be recorded, and (b) the emission of the shorter-lived
probe decays to below the detectable limit while that of the other still can be measured. We refer to this new scheme as the
dual lifetime determination (DLD) method and show that it can be widely varied by appropriate choice of probes and experimental
settings. DLD is demonstrated to work by sensing oxygen and temperature independently from each other by making use of two
probes, one for oxygen (a platinum porphyrin dissolved in polystyrene), and one for temperature [a europium complex dissolved
in poly(vinyl methylketone)]. DLD was applied to monitor the consumption of oxygen in the glucose oxidase-catalyzed oxidation
of glucose at varying temperatures. The scheme is expected to have further applications in cellular assays and biophysical
imaging.
Figure Principle behind the dual lifetime determination (DLD) method 相似文献