Search query: Quantum dot bioconjugates for ultrasensitive nonisotopic detection

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abstract: Highly luminescent semiconductor quantum dots (zinc sulfide capped cadmium selenide) have been covalently coupled to biomolecules for use in ultrasensitive biological detection. In comparison with organic dyes such as rhodamine, this class of luminescent labels is 20 times as bright, 100 times as stable against photobleaching, and one third as wide in spectral linewidth. These nanometer sized conjugates are water soluble and biocompatible. Quantum dots that were labeled with the protein transferrin underwent receptor mediated endocytosis in cultured HeLa cells, and those dots that were labeled with immunomolecules recognized specific antibodies or antigens.
author_names: Warren C W Chan

Shuming Nie
title: Quantum dot bioconjugates for ultrasensitive nonisotopic detection.
venue: Science
year: 1998

abstract: Quantum dots (QDs) are a special type of engineered nanomaterials with outstanding optoelectronic properties that make them as a very promising alternative to conventional luminescent dyes in biomedical applications, including biomolecule (BM) targeting, luminescence imaging and drug delivery. A key parameter to ensure successful biomedical applications of QDs is the appropriate surface modification, i.e. the surface of the nanomaterials should be modified with the appropriate functional groups to ensure stability in aqueous solutions and it should be conjugated with recognition elements capable of ensuring an efficient tagging of the BMs of interest. In this review we summarize the most relevant strategies used for surface modification of QDs and for their conjugation to BMs in preparation of their application in nanoplatforms for luminescent BM sensing and imaging guided targeting. The applications of conjugations of photoluminescent QDs with different BMs in both in vitro and in vivo chemical sensing, immunoassays or luminescence imaging are reviewed. Recent progress in the application of functionalized QDs in ultrasensitive detection in bioanalysis, diagnostics and imaging strategies are reported. Finally, some key future research goals in the progress of bioconjugation of QDs for diagnosis are identified, including novel synthetic approaches, the need for exhaustive characterization of bioconjugates and the design of signal amplification schemes.
author_names: Maria Diaz-Gonzalez

Alfredo de la Escosura-Muniz

Maria Teresa Fernandez-Arguelles

Francisco Javier Garcia Alonso

Jose Manuel Costa-Fernandez
title: Quantum Dot Bioconjugates for Diagnostic Applications
venue: Topics in Current Chemistry
year: 2020

abstract: A selective aptasensor was developed using the electrochemical transduction method for the ultrasensitive detection of cocaine. In this method, dendrimer quantum dot (Den QD) bioconjugate was utilized as a specific nanocomposite to efficiently fabricate the aptasensor. CdTe QD, which carries highly significant properties, was immobilized on the surface of a glassy carbon electrode (GCE) and polyamidoamine (PAMAM) dendrimer (Den) was covalently attached to the carboxyl terminated surface of the CdTe QDs. This clever combination of QD and Den provides a highly stable matrix for the increased loading of aptamer (Apt) as a cocaine molecular receptor via covalent attachment. The Apt was functionalized with AuNPs leading to the amplification of the electrochemical signal. In this study, upon the incubation of cocaine on the aptasensor surface, the peak current of the redox probe decreased due to the hindered electron transfer reaction on the sensing surface. It has shown that the proposed aptasensor can detect cocaine by electrochemical impedance spectroscopy (EIS) technique at a linear range (5.00 10 3 6.00 nM) and a capability of detection down to 1.60 pM. The excellent specificity of this sensing system is demonstrated by using some common analgesic drugs, and finally, the proposed aptasensor was successfully used to measure cocaine in the human serum sample. The proposed methodology may hold great promise for the design of other aptasensors and immunosensors based on the use of the Den QD bioconjugate as a nanocomposite with high performance.
author_names: Mahmoud Roushani

Faezeh Shahdost-fard
title: Applicability of the Dendrimer quantum Dot (Den QD) Bioconjugate as a Novel Nanocomposite for Signal Amplification in the Fabrication of Cocaine Aptasensor
year: 2019

abstract: Exploration of quantum dots (QDs) as energy acceptors revolutionizes the current chemiluminescence resonance energy transfer (CRET) since QDs possess large Stokes shifts and high luminescence efficiency. However, the strong and high concentration of oxidant (typically H2O2) needed for luminol chemiluminescence (CL) reaction could cause oxidative quenching to QDs, thereby decreasing the CRET performance. Here we proposed the use of bienzyme QDs bioconjugate as the energy acceptor for improved CRET sensing. Two enzymes, one for H2O2 generation (oxidase) and another for H2O2 consumption (horseradish peroxidase, HRP) were bioconjugated onto the surface of QDs. The bienzyme allowed fast in situ cascaded H2O2 generation and consumption, thus alleviating fluorescence quenching of QDs. The nanosized QDs accommodate the two enzymes in a nanometric range, and the CL reaction was confined on the surface of QDs accordingly, thereby amplifying the CL reaction rate and improving CRET efficiency. As a result, CRET efficiency of 30 38% was obtained; the highest CRET efficiency by far was obtained using QDs as the energy acceptor. The proposed CRET system could be explored for ultrasensitive sensing of various oxidase substrates (here exemplified with cholesterol, glucose, and benzylamine) allowing for quantitative measurement of a spectrum of metabolites with high sensitivity and specificity. Limits of detection (LOD, 3s) for cholesterol, glucose, and benzylamine were found to be 0.8, 3.4, and 10 nM, respectively. Furthermore, multiparametric blood analysis (glucose and cholesterol) is demonstrated.
author_names: Shuxia Xu

Xianming Li

Chaobi Li

Jialin Li

Xinfeng Zhang

Peng Wu

Xiandeng Hou
title: In Situ Generation and Consumption of H2O2 by Bienzyme Quantum Dots Bioconjugates for Improved Chemiluminescence Resonance Energy Transfer.
venue: Analytical chemistry
year: 2016

abstract: Herein we demonstrate the protocol of a biocatalytic precipitation (BCP) based sandwich photoelectrochemical (PEC) horseradish peroxidase (HRP) linked immunoassay on the basis of their synergy effect for the ultrasensitive detection of mouse IgG (antigen, Ag) as a model protein. The hybrid film consisting of oppositely charged polyelectrolytes and CdS quantum dots (QDs) is developed by the classic layer by layer (LbL) method and then employed as the photoactive antibody (Ab) immobilization matrix for the subsequent sandwich type Ab Ag affinity interactions. Improved sensitivity is achieved through using the bioconjugates of HRP secondary antibodies (Ab(2) In addition to the much enhanced steric hindrance compared with the original one, the presence of HRP would further stimulate the BCP onto the electrode surface for signal amplification, concomitant to a competitive nonproductive absorption that lowers the photocurrent intensity. As a result of the multisignal amplification in this HRP catalyzed BCP based PEC immunoassay, it possesses excellent analytical performance. The antigen could be detected from 0.5 pg/mL to 5.0 ng/mL with a detection limit of 0.5 pg/mL.
author_names: Wei-Wei Zhao

Zheng-Yuan Ma

Pei Yu

Xiao-Ya Dong

Jingjuan Xu

Hong-Yuan Chen
title: Highly sensitive photoelectrochemical immunoassay with enhanced amplification using horseradish peroxidase induced biocatalytic precipitation on a CdS quantum dots multilayer electrode.
venue: Analytical chemistry
year: 2012

abstract: An ultrasensitive photoelectrochemical immunoassay of cancer biomarker a fetoprotein (AFP) is proposed that uses titanium dioxide (TiO(2) coupled with AFP CdTe GOx bioconjugate, which featured AFP antigen and glucose oxidase (GOx) labels linked to CdTe quantum dots (QDs) for signal amplification. The synthesized CdTe QDs yielded a homogeneous and narrow size distribution, which allowed the binding of AFP and GOx on CdTe QDs. Greatly enhanced sensitivity for AFP came from a dual signal amplification strategy. First, an effective matching of energy levels between the conduction bands of CdTe QDs and TiO(2) allowed for fast electron injection from excited CdTe QDs to TiO(2) upon irradiation, which reduced the recombination process of electron hole pairs and prompted photoelectrochemical performance. Second, GOx enzyme could catalyze glucose to produce H(2)O(2) which acted as a sacrificial electron donor to scavenge the photogenerated holes in the valence band of CdTe QDs, further causing an enhanced photocurrent. Thus, on the basis of the dual signal amplification strategy, the competitive immunosensor based on the specific binding of anti AFP antibodies to AFP and AFP CdTe GOx bioconjugates was achieved. This proposed biosensor for AFP possessed largely increased linear detection range from 0.5 pg/mL to 10 mg/mL with a detection limit of 0.13 pg/mL. The proposed amplification strategy shows high sensitivity, stability, and reproducibility and can become a promising platform for other protein detection.
author_names: Yongjie Li

Mengyao Ma

Jun-Jie Zhu
title: Dual signal amplification strategy for ultrasensitive photoelectrochemical immunosensing of a fetoprotein.
venue: Analytical chemistry
year: 2012

abstract: Herein, we describe an ultrasensitive specific biosensing system for detection of sarcosine as a potential biomarker of prostate carcinoma based on Forster resonance energy transfer (FRET) The FRET biosensor employs anti sarcosine antibodies immobilized on paramagnetic nanoparticles surface for specific antigen binding. Successful binding of sarcosine leads to assembly of a sandwich construct composed of anti sarcosine antibodies keeping the Forster distance (Ro) of FRET pair in required proximity. The detection is based on spectral overlap between gold functionalized green fluorescent protein and antibodies@quantum dots bioconjugate (lex 400 nm) The saturation curve of sarcosine based on FRET efficiency (F604/F510 ratio) was tested within linear dynamic range from 5 to 50 nM with detection limit down to 50 pM. Assembled biosensor was then successfully employed for sarcosine quantification in prostatic cell lines (PC3, 22Rv1, PNT1A) and urinary samples of prostate adenocarcinoma patients.
author_names: Zbynek Heger

Natalia Cernei

Sona Krizkova

Michal Masarik

Pavel Kopel

Petr Hodek

Ondrej Zitka

Vojtech Adam

Rene Kizek
title: Paramagnetic Nanoparticles as a Platform for FRET Based Sarcosine Picomolar Detection
venue: Scientific reports
year: 2015

abstract: In this paper, we demonstrate the spectral encoding capabiliry of quantum dot nanocrystals (QDs) We mixed two direrent sizes of QDs in a resin, and two photon ercitation at various wavelengths showed that the relative intensities of the fluorescence @om two QDs varied significantly. Such a difference in level of absorption at direrent wavelengths allows one to record information only on one size of QDs, without affecting the other sized QDs. This properry can be applied to optical data storagev so thal storage dens@ can be greatly improved. Recently, three dimensional (3 D) optical storage has been receiving much attention due to its ability to overcome the current two dimensional optical storage capacity limit imposed by the diffraction limit of light [l] However, due to the problems of aberration and scattering of recording beam inside the medium, it is likely that the 3 D optical storage tecbnique'will quickly hit its capacity limit. One possible way of overcoming this issue is by incorporating other physical dimensions, which are not in spatial domain, into 3 D optical storage. In this paper, we demonstrate spectrally encoded optical data storage by using quantum dot nanocrystals (QDs) The QDs have received so much attention because of their interesting properties such as emission wavelength tunability with size, narrow emission bandwidths and discrete atom like energy level structures [2] In particular, the discrete energy level structure permits their fluorescence intensities to vary with an excitation wavelength [2] When two different sizes of QDs are mixed, the differences in energy level structures can be manifested by variation in relative intensities of the two fluorescence wavelengths with respect to the excitation wavelengths. This is shown in Figure 1, where the fluorescence spectrum of green QDs (3 nm in diameter) mixed together wiih red QDs (6 nm diameter)'are shown, excited by various near infrared wavelengths (twophoton absorption) The peak intensities of two QDs are plotted against the excitation wavelengths, shown in Figure lb. The two photon absorption of the QDs is proved in a log log plot of the fluorescence intensity with respect to the input power, which is shown in Figure IC. The figures show that at certain wavelengths, each coloured QD shows increased absorption, and therefore more interactions with excitation light such as bleaching or quenching are expected [3] Such properties can be further utilized in optical storage, where marks can be recorded on one type of QDs at a certain wavelength without affecting the other QDs. In the talk, further development of the QD based spectral encoding will be presented. Figure 1. (a) Two photon fluorescence spectrum of mixed QDs in resin at difference excitation wavelength. Note the relative change in intensities of two QDs. (b) Fluorescence peak intensities of QDs are plotted against excitation wavelengths. (c) Two photon absorption of QDs are confirmed by the log log plot References 1. D. McPhail and M. Gu, "Use of polarization sensitivity for three dimensional optical data storage in polymer dispersed liquid crystals under two photon illumination," Appl. Phys. Lett. 81, ppll60 (2002) 2. W. C. W. Chan and S. Nie, "Quantum dot bioconjugates for ultrasensitive nonisotopic detection," Science, 281, pp2016 2018 (1998) 3. S. A. Blanton, M. A. Hines, M. E. Schmidt, and P. Guyot Sionnest, "Two photon spectroscopy and microscopy of 11 VI semiconductor nanocrystals," J. Lumines. 70, pp253 268 (1996) 0 7803 7766 4103A17 00 02003 IEEE
author_names: James W M Chon
title: W4H4 9) 4 USE OF QUANTUM DOT NANOCRYSTALS FOR SPECTRALLY ENCODED OPTICAL DATA STORAGE
year: 2004

abstract: Foreword. Preface. List of Contributors. PART I: FUNDAMENTAL CONSIDERATIONS. Chapter 1. Chemical Sensing. Chapter 2. What to Detect? Chapter 3. Dangerous Innovations. Chapter 4. Where Should We Look For Explosive Molecules? Chapter 5. Structure of Turbulent Chemical Plumes. PART II: FIELD EXPERIENCE. Chapter 6. Detection of Trace Explosive Signatures in the Marine Environment. Chapter 7. Explosives Detection Using Ultrasensitive Electronic Vapor Sensors: Field Experience. Chapter 8. Reflections on Hunting Mines By Aroma Sensing. PART III: EXAMPLE SENSING TECHNOLOGIES. Chapter 9. Explosives Detection Based on Amplifying Fluorescence Polymers. Chapter 10. Ion Mobility Spectrometry. Chapter 11. Mass Spectrometry For Security Screening of Explosives. Chapter 12. Explosive Vapor Detection Using Microcantilever Sensors. Chapter 13. Lab On A Chip Detection of Explosives. Chapter 14. Nanoscale Sensing Assemblies Using Quantum Dot Protein Bioconjugates. Chapter 15. Remote Sensing of Explosive Materials Using Differential Reflection Spectroscopy. PART IV: SUPPLEMENTARY MATERIAL. Appendix Organizations Involved in Searching For Hidden Explosives. Definitions, Symbols and Abbreviations. Explosives Definitions. Bibliography. Index.
author_names: Ronald L Woodfin
title: Trace chemical sensing of explosives
year: 2007

abstract: We report a method for single molecule detection and biomolecular structural mapping based on dual color imaging and automated colocalization of bioconjugated nanoparticle probes at nanometer precision. In comparison with organic dyes and fluorescent proteins, nanoparticle probes such as fluorescence energy transfer nanobeads and quantum dots provide significant advantages in signal brightness, photostability, and multicolor light emission. As a result, we have achieved routine two color superresolution imaging and single molecule detection with standard fluorescence microscopes and inexpensive digital color cameras. By using green and red nanoparticles to simultaneously recognize two binding sites on a single target, individual biomolecules such as nucleic acids are detected and identified without target amplification or probe/target separation. We also demonstrate that a powerful astrophysical method (originally developed to analyze crowded stellar fields) can be used for automated and rapid statistical analysis of nanoparticle colocalization signals. The ability to rapidly localize bright nanoparticle probes at nanometer precision has implications not only for ultrasensitive medical detection but also for structural mapping of molecular complexes in which individual components are tagged with color coded nanoparticles.
author_names: Amit Agrawal

Rajesh P Deo

Geoffrey D Wang

May D Wang

Shuming Nie
title: Nanometer scale mapping and single molecule detection with color coded nanoparticle probes
venue: Proceedings of the National Academy of Sciences
year: 2008