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Deterministic bead-in-droplet ejection utilizing an integrated plug-in bead dispenser for single bead-based applications. Sci Rep 2017; 7:46260. [PMID: 28393911 PMCID: PMC5385560 DOI: 10.1038/srep46260] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/13/2017] [Indexed: 02/03/2023] Open
Abstract
This paper presents a deterministic bead-in-droplet ejection (BIDE) technique that regulates the precise distribution of microbeads in an ejected droplet. The deterministic BIDE was realized through the effective integration of a microfluidic single-particle handling technique with a liquid dispensing system. The integrated bead dispenser facilitates the transfer of the desired number of beads into a dispensing volume and the on-demand ejection of bead-encapsulated droplets. Single bead–encapsulated droplets were ejected every 3 s without any failure. Multiple-bead dispensing with deterministic control of the number of beads was demonstrated to emphasize the originality and quality of the proposed dispensing technique. The dispenser was mounted using a plug-socket type connection, and the dispensing process was completely automated using a programmed sequence without any microscopic observation. To demonstrate a potential application of the technique, bead-based streptavidin–biotin binding assay in an evaporating droplet was conducted using ultralow numbers of beads. The results evidenced the number of beads in the droplet crucially influences the reliability of the assay. Therefore, the proposed deterministic bead-in-droplet technology can be utilized to deliver desired beads onto a reaction site, particularly to reliably and efficiently enrich and detect target biomolecules.
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Zhang Y, Liao Z, Liu Y, Wan Y, Chang J, Wang H. Flow cytometric immunoassay for aflatoxin B1 using magnetic microspheres encoded with upconverting fluorescent nanocrystals. Mikrochim Acta 2017. [DOI: 10.1007/s00604-017-2116-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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3
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Zhuang SH, Guo XX, Wu YS, Chen ZH, Chen Y, Ren ZQ, Liu TC. Quantum Dot-Based Luminescent Oxygen Channeling Assay for Potential Application in Homogeneous Bioassays. J Fluoresc 2015; 26:317-22. [DOI: 10.1007/s10895-015-1716-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 10/28/2015] [Indexed: 11/30/2022]
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Vaidya SV, Couzis A, Maldarelli C. Reduction in aggregation and energy transfer of quantum dots incorporated in polystyrene beads by kinetic entrapment due to cross-linking during polymerization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3167-79. [PMID: 25674811 DOI: 10.1021/la503251s] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report the development of barcoded polystyrene microbeads, approximately 50 μm in diameter, which are encoded by incorporating multicolored semiconductor fluorescent nanocrystals (quantum dots or QDs) within the microbeads and using the emission spectrum of the embedded QDs as a spectral label. The polymer/nanocrystal bead composites are formed by polymerizing emulsified liquid droplets of styrene monomer and QDs suspended in an immiscible continuous phase (suspension polymerization). We focus specifically on the effect of divinylbenzene (DVB) added to cross-link the linearly growing styrene polymer chains and the effect of this cross-linking on the state of aggregation of the nanocrystals in the composite. Aggregated states of multicolor QDs give rise to nonradiative resonance energy transfer (RET) which distorts the emission label from a spectrum recorded in a reference solvent in which the nanocrystals are well dispersed and unaggregated. A simple barcode is chosen of a mixture of QDs emitting at 560 (yellow) and 620 nm (red). We find that for linear chain growth (no DVB), the QDs aggregate as is evident from the emission spectrum and the QD distribution as seen from confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM) images. Increasing the extent of cross-linking by the addition of DVB is shown to significantly decrease the aggregation and provide a clear label. We suggest that in the absence of cross-linking, linearly growing polymer chains, through enthalpic and entropic effects, drive the nanocrystals into inclusions, while cross-linking kinetically entraps the particle and prevents their aggregation.
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Affiliation(s)
- Shyam V Vaidya
- Department of Chemical Engineering, City College of New York, 160 Convent Avenue, New York, New York 10031, United States
| | - Alex Couzis
- Department of Chemical Engineering, City College of New York, 160 Convent Avenue, New York, New York 10031, United States
| | - Charles Maldarelli
- Department of Chemical Engineering, City College of New York, 160 Convent Avenue, New York, New York 10031, United States
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Quantum-dot-based homogeneous time-resolved fluoroimmunoassay of alpha-fetoprotein. Anal Chim Acta 2012; 741:100-5. [DOI: 10.1016/j.aca.2012.06.042] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 06/18/2012] [Accepted: 06/20/2012] [Indexed: 11/24/2022]
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6
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Guan LY, Li YQ, Lin S, Zhang MZ, Chen J, Ma ZY, Zhao YD. Characterization of CdTe/CdSe quantum dots-transferrin fluorescent probes for cellular labeling. Anal Chim Acta 2012; 741:86-92. [PMID: 22840708 DOI: 10.1016/j.aca.2012.06.043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 06/20/2012] [Accepted: 06/21/2012] [Indexed: 10/28/2022]
Abstract
In this paper, we prepared three types of transferrin-quantum dots conjugates (QDs-Tf) using three different methods (electrostatic interaction, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) coupling, denatured transferrin (dTf) coating). Fluorescence emission spectra, surface characteristics, zeta potentials of quantum dots (QDs) and QDs-Tf fluorescent probes were characterized by spectrophotometer, capillary electrophoresis, and dynamic light scattering. Fluorescent imaging of HeLa cells was also performed by QDs and QDs-Tf fluorescent probes. It was found that the fluorescence imaging performances of QDs-Tf probes prepared by electrostatic interaction and EDC coupling were better compared with the one prepared by dTf coating. Then a real-time single cell detection system was established to quantitatively evaluate cell labeling effects of QDs-Tf fluorescent probes. It was found that for cell labeling efficiency, the proportion of cells labeled by quantum dot probes to a group of cells, QDs-Tf probe prepared by EDC coupling showed the highest labeling efficiency (85.55±3.88%), followed by electrostatic interaction (78.86±9.57%), and dTf coating showed the lowest (40.09±10.2%). This efficiency order was confirmed by flow cytometry results. This study demonstrated the relationship between conjugation methods and the resultant QDs-Tf probes and provided a foundation for choosing appropriate QDs-Tf probes in cell labeling.
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Affiliation(s)
- Li-Yun Guan
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Department of Biomedical Engineering, Wuhan, HuBei 430074, PR China
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Zhimin Yuan, Wang J, Yang P. Highly luminescent CdTe/CdS/ZnO core/shell/shell quantum dots fabricated using an aqueous strategy. LUMINESCENCE 2012; 28:169-75. [DOI: 10.1002/bio.2358] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 12/20/2011] [Accepted: 02/01/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Zhimin Yuan
- School of Material Science and EngineeringUniversity of Jinan 250022 Jinan China
| | - Jianrong Wang
- School of Material Science and EngineeringUniversity of Jinan 250022 Jinan China
| | - Ping Yang
- School of Material Science and EngineeringUniversity of Jinan 250022 Jinan China
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Wang G, Zhang P, Dou H, Li W, Sun K, He X, Han J, Xiao H, Li Y. Efficient incorporation of quantum dots into porous microspheres through a solvent-evaporation approach. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:6141-6150. [PMID: 22428794 DOI: 10.1021/la300066c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Quantum dot (QD)-encoded microspheres play an important role in suspension arrays by acting as supports for various reactions between biomolecules. With regard to QD-encoded microspheres utilized in suspension arrays, three key requirements are controllable size, abundant surface functional groups, and especially excellent fluorescence properties. In this paper, narrowly dispersed poly(styrene-co-divinylbenzene-co-methylacrylic acid) (PSDM) microspheres with specific size, surface carboxyl groups, and porous structures were synthesized by seeded copolymerization. In order to improve the incorporation efficiency of QDs within microspheres, we developed a swelling-evaporation approach in which the swelling process was combined with gradual evaporation of the solvent and thus gradual concentration of QDs in the dispersion solution. This approach was demonstrated to be an efficient method for improving the fluorescence intensity of resultant microspheres compared with the use of swelling alone. Moreover, the porous structure was shown to aid the penetration of QDs into the interiors of the microspheres. Through this approach, microspheres encoded with either single or multiple wavelength-emitting QDs were fabricated effectively. The suspension immunoassays were then founded based on the QD-encoded microspheres, by coating mouse antihuman chorionic gonadotropin as the probe for goat antimouse IgG detection. The positive results determined by Luminex 100 and the low cytotoxicity of the QD-encoded microspheres demonstrated their great potential in suspension arrays.
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Affiliation(s)
- Gang Wang
- The State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240 PR China
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Abstract
The development of quantum dot (QD) technology represents one of the most dramatic advances in flow cytometry history, offering the opportunity for highly multiplexed experiments and allowing better resolution of dimly staining markers. Here, we guide users through the technical aspects of using QDs (including instrumentation and antibody conjugation), demonstrate why QDs are useful in multicolor flow cytometry, and describe some of the challenges investigators may face when adopting this technology.
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XU GF, LI H, ZHANG C, SUN ZY, ZHONG WY, XU DK, CHEN HY. Research and Application of Visual Detection Based on Quantum Dots Coupled with Silver Enhancement. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2010. [DOI: 10.1016/s1872-2040(09)60069-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zhang HL, Li YQ, Zhang MZ, Zhao YD. Real-time observation of the effect of iron on receptor-mediated endocytosis of transferrin conjugated with quantum dots. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:045003. [PMID: 20799798 DOI: 10.1117/1.3465595] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The optical properties of antiphotobleaching and the advantage of long-term fluorescence observation of quantum dots are fully adopted to study the effects of iron on the endocytosis of transferrin. Quantum dots are labeled for transferrin and endocytosis of transferrin in HeLa cells is observed under the normal state, iron overloading, and an iron-deficient state. In these three states, the fluorescence undergoes a gradual process of first dark, then light, and finally dark, indicating the endocytosis of transferrin. The fluorescence intensity analysis shows that a platform emerges when fluorescence changes to a certain degree in the three states. Experienced a same period of time after platform, the fluorescence strength of cells in the normal state is 1.2 times the first value, and the iron-deficiency state is 1.4 times, but the iron overloading state was 0.85 times. We also find that the average fluorescence intensity in cells detected by the spectrophotometer in the iron-deficiency state is almost 7 times than that in a high iron state. All this proves that iron overloading would slow the process, but iron deficiency would accelerate endocytosis. We advance a direct observational method that may contribute to further study of the relationship of iron and transferrin.
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Affiliation(s)
- Hai-Li Zhang
- Huazhong University of Science and Technology, Wuhan National Laboratory for Optoelectronics, Britton Chance Center for Biomedical Photonics, Wuhan, Hubei, China
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Algar WR, Krull UJ. Developing mixed films of immobilized oligonucleotides and quantum dots for the multiplexed detection of nucleic acid hybridization using a combination of fluorescence resonance energy transfer and direct excitation of fluorescence. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:6041-6047. [PMID: 20000340 DOI: 10.1021/la903751m] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Methods have been developed for the simultaneous and selective detection of three target nucleic acid sequences based on mixed films of immobilized quantum dots (QDs) and oligonucleotide probes. CdSe/ZnS QDs were immobilized on optical fibers and conjugated with mixtures of different probe oligonucleotides. Hybridization events were detected using a combination of fluorescence from direct excitation and fluorescence sensitized by resonance energy transfer (FRET). A sandwich assay format was used to associate dye labeled reporter oligonucleotides with probe-target hybrids formed at the surface of the optical fiber. One detection channel utilized direct excitation of Pacific Blue and the two other detection channels were based on FRET. In one strategy, green emitting QDs were used as donors with Cy3 and Rhodamine Red-X acceptors. In a second strategy, green and red emitting QDs were coimmobilized and used as donors with Cy3 and Alexa Fluor 647 acceptors, respectively. Selective three-plex detection was demonstrated with both strategies. Several key design criteria that were explored to optimize the relative signal magnitude between channels included: the ratio of probe associated with direct excitation versus probes associated with FRET; the relative amounts of each FRET probe and corresponding spectral overlap; and the photoluminescence ratio between immobilized green and red emitting QDs (where applicable). Careful selection of probe sequences and lengths were important for the discrimination of single nucleotide polymorphisms in one channel without suppressing binding of target in the other two channels. This work provides a basis for the development of multiplexed biosensors that are ensemble compatible and do not require discrete sensor elements, spatial registration, sorting technology, or single molecule spectroscopy.
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Affiliation(s)
- W Russ Algar
- Chemical Sensors Group, Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Road, North, Mississauga, Ontario, L5L 1C6, Canada
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Cao M, Liu M, Cao C, Xia Y, Bao L, Jin Y, Yang S, Zhu C. A simple fluorescence quenching method for berberine determination using water-soluble CdTe quantum dots as probes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 75:1043-1046. [PMID: 20093069 DOI: 10.1016/j.saa.2009.12.050] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 12/06/2009] [Accepted: 12/14/2009] [Indexed: 05/28/2023]
Abstract
A novel method for the determination of berberine has been developed based on quenching of the fluorescence of thioglycolic acid-capped CdTe quantum dots (TGA-CdTe QDs) by berberine in aqueous solutions. Under optimum conditions, the relative fluorescence intensity was linearly proportional to the concentration of berberine between 2.5x10(-8) and 8.0x10(-6)mol L(-1) with a detection limit of 6.0x10(-9)mol L(-1). The method has been applied to the determination of berberine in real samples, and satisfactory results were obtained. The mechanism of the proposed reaction was also discussed.
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Affiliation(s)
- Ming Cao
- Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, PR China
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Chattopadhyay PK, Perfetto SP, Yu J, Roederer M. The use of quantum dot nanocrystals in multicolor flow cytometry. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2010; 2:334-48. [DOI: 10.1002/wnan.75] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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Zhang Z, Long Y, Pan J, Yan X. Preparation of fluorescence-encoded microspheres in a core–shell structure for suspension arrays. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/b919955a] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Jun BH, Noh MS, Kim G, Kang H, Kim JH, Chung WJ, Kim MS, Kim YK, Cho MH, Jeong DH, Lee YS. Protein separation and identification using magnetic beads encoded with surface-enhanced Raman spectroscopy. Anal Biochem 2009; 391:24-30. [DOI: 10.1016/j.ab.2009.05.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 05/01/2009] [Accepted: 05/05/2009] [Indexed: 10/20/2022]
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18
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Qin Z, Chen S, Lu T, Zeng S, Sun J, Lv J, Hua Q, Wu A. Simultaneous Screening for Five Veterinary Drug Residues by a Developed Multiplexed Luminex Assay. ANAL LETT 2009. [DOI: 10.1080/00032710802585667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Wang HQ, Zhang HL, Li XQ, Wang JH, Huang ZL, Zhao YD. Solubilization and bioconjugation of QDs and their application in cell imaging. J Biomed Mater Res A 2008; 86:833-41. [PMID: 18041709 DOI: 10.1002/jbm.a.31682] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Quantum dot (QD) solubilization, conjugation with biomolecules, column purification, and labeling of human HepG2 cells with transferrin-QD (Tf-QD) conjugates are reported in detail in this article. Water-soluble QDs (WQDs) were obtained using sodium thiolycolate to replace the surface ligand tri-n-octylphosphine oxide (TOPO) on the surface of oil-soluble QDs, and Tf-QD conjugates were produced by coupling Tf to WQD. The resulting Tf-QDs were characterized by UV and luminescence spectrophotometry and purified by Sephadex column. The results indicate that Tf has been conjugated to QD successfully. Based on transferrin/transferrin-receptor-mediated delivery system, the Tf-QD conjugates were used to label human HepG2 cells. After a short incubation, the QDs were mainly localized to the membrane of cells. After 12-h incubation, QDs appear mainly in the cytoplasm portion. However, QDs were not found in the nucleus of the cells. Furthermore, the fluorescence intensity of QDs in the cells reduces gradually over time, and fluorescence cannot be observed after 10 days. However, the growth of the labeled cells was not markedly affected by the toxicity of QDs, and they are alive for 10 days. These results can be used for further application of QDs in bioscience.
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Affiliation(s)
- Hai-Qiao Wang
- Key Laboratory of Biomedical Photonics of Ministry of Education-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, HuBei 430074, People's Republic of China
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Liu M, Xu L, Cheng W, Zeng Y, Yan Z. Surface-modified CdS quantum dots as luminescent probes for sulfadiazine determination. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008; 70:1198-1202. [PMID: 18201928 DOI: 10.1016/j.saa.2007.10.040] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Revised: 10/30/2007] [Accepted: 10/30/2007] [Indexed: 05/25/2023]
Abstract
A novel, sensitive and convenient determine technology based on the quenching of the fluorescence intensity of functionalized CdS quantum dots by sulfadiazine was proposed. Luminescent CdS semiconductor quantum dots (QDs) modified by thioglycollic acid (TGA) were synthesized with the microwave method. The modified CdS QDs are water-soluble, stable and highly luminescent. The possible mechanism for the reaction was also discussed. When sulfadiazine was added into the CdS QDs colloid solution, the surface of CdS QDs generates the electrostatic interaction in aqueous medium, which induces the quenching of fluorescence emission at 489 nm. Under optimum condition, the fluorescence intensity versus sulfadiazine concentration gave a linear response according Stern-Volmer equation with an excellent 0.9981 correlation coefficient. The linearity range of the calibration curve was 1.2 x 10(-5) to 2.13 x 10(-3) mol L(-1). The limit of detection (3delta) is 8.0 micromol L(-1). The relative standard deviation for five determinations of 0.13 x 10(-3)mol L(-1) sulfadiazine is 1.4%. The concentrations of sulfadiazine injections were determined by the proposed method with a satisfactory result.
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Affiliation(s)
- Mingming Liu
- Department of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009, China
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Abstract
We critically evaluate the usefulness of different nanostructures described as labels, nanoscaffolds or separation media in immunoassays and nucleic-acid hybridization assays. Many of the great number of publications describe only theoretical aspects of using these nanostructures or nanoparticles, but do not verify their applicability in the presence of potential interferents that can be present in the sample matrix. We attempt a systematic study of the advantages and the limitations of using these new reagents in bioassays, the different assay formats for individual and multiplexed detection, and the capability of these assays in analyzing real samples.
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Affiliation(s)
- A. Gómez-Hens
- Department of Analytical Chemistry, “Marie Curie Annex” Building, Campus of Rabanales, University of Córdoba, E-14071 Córdoba, Spain
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Zhu XX, Cao YC, Jin X, Yang J, Hua XF, Wang HQ, Liu B, Wang Z, Wang JH, Yang L, Zhao YD. Optical encoding of microbeads based on silica particle encapsulated quantum dots and its applications. NANOTECHNOLOGY 2008; 19:025708. [PMID: 21817557 DOI: 10.1088/0957-4484/19/02/025708] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A novel method concerning the coding technology of polystyrene beads with Si encapsulated quantum dot (QD) particles (Si@QDs particles) is studied in this paper. In the reverse microemulsion system containing tetraethoxysilane (TEOS), water-soluble QDs (emission peak at 600 nm) were enveloped within the silica shell, forming Si@QDs particles. The Si@QDs particles were characterized by TEM, showing good uniform size, with an average diameter of about 167.0 nm. In comparison with the pure water-soluble QDs, the encapsulation of water-soluble QDs in the silica shell led to an enhancement in anti-photobleaching by providing inert barriers for the QDs. Images presented by SEM and confocal laser scanning microscopy demonstrated that the Si@QDs particles were equably coated on the surface of carboxyl functionalized polystyrene (PS) beads. Then, with the assistance of ethyl-3-(dimethyl aminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS), human IgG could be successfully crosslinked to Si@QDs particle coated PS-COOH beads. Furthermore, the Si@QDs coated PS-COOH beads with human IgG were examined in immunoassay experiments, and the results indicated that these beads could be applied in the specific recognition of goat-anti-human IgG in solution. This investigation is expected to provide a new route to bead coding in the field of suspension microarrays, based on the use of QDs.
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Affiliation(s)
- Xiao-Xia Zhu
- Key Laboratory of Biomedical Photonics of Ministry of Education-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, HuBei 430074, People's Republic of China. Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, HuBei, 430074, People's Republic of China
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Battersby BJ, Trau M. Optically Encoded Particles and Their Applications in Multiplexed Biomedical Assays. Aust J Chem 2007. [DOI: 10.1071/ch07006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In the future, the rapid discovery of new cures, vaccines, and diagnostics for common diseases will depend on the ability of biomedical researchers to investigate complex mixtures of proteins or DNA. The need to measure the abundance of these entities, together with their level of interaction, has driven the development of new research tools that enable simultaneous analysis of multiple analytes (multiplexing). Optically encoded particles are emerging as the multiplexing tools of choice, especially for clinical research. In this Review, an overview of various new optical encoding methods will be presented, together with important biomedical applications in which particle-based assays are currently being used.
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