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Lambert A, Yang Z, Cheng W, Lu Z, Liu Y, Cheng Q. Ultrasensitive Detection of Bacterial Protein Toxins on Patterned Microarray via Surface Plasmon Resonance Imaging with Signal Amplification by Conjugate Nanoparticle Clusters. ACS Sens 2018; 3:1639-1646. [PMID: 30084634 DOI: 10.1021/acssensors.8b00260] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sensitive detection and monitoring of biological interactions in a high throughput, multiplexed array format has numerous advantages. We report here a method to enhance detection sensitivity in surface plasmon resonance (SPR) spectroscopy and SPR imaging via the effect of accumulation of conjugated nanoparticles of varying sizes. Bacterial cholera toxin (CT) was chosen for the demonstration of enhanced immunoassay by SPR. After immobilization of CT on a gold surface, specific recognition is achieved by biotinylated anti-CT. The signal is amplified by the attachment of biotinylated 20 nm AuNP via streptavidin bridge, followed by attachment of 5 nm streptavidin-functionalized Fe3O4NP to the AuNP-biotin surface. The continuous surface binding of two differently sized conjugated nanoparticles effectively increases their packing density on surface and significantly improves SPR detection sensitivity, allowing quantitative measurement of CT at very low concentration. The dense packing of conjugated nanoparticles on the surface was confirmed by atomic force microscopy characterization. SPR imaging of the immunoassay for high-throughput analysis utilized an Au-well microarray that attenuated the background resonance interference on the resulting images. A calibration curve of conjugated nanoparticle binding signal amplification for CT detection based on surface coverage has been obtained that shows a correlation in a range from 6.31 × 10-16 to 2.51 × 10-13 mol/cm2 with the limit of detection of 5.01 × 10-16 mol/cm2. The absolute quantity of detection limit using SPR imaging was 0.25 fmol. The versatile nanoparticles and biotin-streptavidin interaction used here should allow adaptation of this enhancement method to many other systems that include DNA, RNA, peptides, and carbohydrates, opening new avenues for ultrasensitive analysis of biomolecules.
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Affiliation(s)
- Alexander Lambert
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Zhanjun Yang
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Wei Cheng
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Zhenda Lu
- College of Engineering and Applied Science, Nanjing University, Nanjing 210023, China
| | - Ying Liu
- Department of Chemistry, Nanjing University, Nanjing 210023, China
| | - Quan Cheng
- Department of Chemistry, University of California, Riverside, California 92521, United States
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Perez L, Mettry M, Hinman SS, Byers SR, McKeating KS, Caulkins BG, Cheng Q, Hooley RJ. Selective protein recognition in supported lipid bilayer arrays by tailored, dual-mode deep cavitand hosts. SOFT MATTER 2017; 13:3966-3974. [PMID: 28512660 PMCID: PMC6041475 DOI: 10.1039/c7sm00192d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Self-folding deep cavitands with variably functionalized upper rims are able to selectively immobilize proteins at a biomimetic supported lipid bilayer surface. The immobilization process takes advantage of the dual-mode binding capabilities of the hosts, combining a defined binding pocket with upper rim charged/H-bonding groups. A variety of proteins can be selectively immobilized at the bilayer interface, either via complementary charge/H-bonding interactions, cavity-based molecular recognition, or a combination of both. The immobilization process can be used to bind unmodified native proteins, epitopes for bioadhesion, or proteins covalently modified with suitable RNMe3+ binding "handles" and charged groups that can either match or mismatch with the cavitand rim. The immobilization process can be monitored in real time using surface plasmon resonance (SPR) spectroscopy, and applied to the construction of cavitand:lipid arrays using the hosts and trehalose vitrified phospholipid vesicles. The selective, dual-mode protein recognition is maintained in the arrays, and can be visualized using SPR imaging.
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Affiliation(s)
- Lizeth Perez
- Department of Chemistry, University of California - Riverside, Riverside, CA 92521, USA.
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Mosca S, Yu Y, Rebek J. Preparative scale and convenient synthesis of a water-soluble, deep cavitand. Nat Protoc 2016; 11:1371-87. [PMID: 27388554 DOI: 10.1038/nprot.2016.078] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cavitands are established tools of supramolecular chemistry and molecular recognition, and they are finding increasing application in sensing and sequestration of physiologically relevant molecules in aqueous solution. The synthesis of a water-soluble, deep cavitand is described. The route comprises six (linear) steps from commercially available precursors, and it relies on the fourfold oligomeric cyclization reaction of resorcinol with 2,3-dihydrofuran that leads to the formation of a shallow resorcinarene framework; condensation with aromatic panels, which deepens the hydrophobic binding cavity; construction of rigid urea functionalities on the upper rim; and the introduction of the water-solubilizing methylimidazolium groups on the lower rim. Late intermediates of the synthesis can be used in the preparation of congener cavitands with different properties and applications, and a sample of such a synthetic procedure is included in this protocol. Emphasis is placed on scaled-up reactions and on purification procedures that afford materials in high yield and avoid chromatographic purification. This protocol provides improvements over previously described procedures, and it enables the preparation of sizable amounts of deep cavitands: 7 g of a water-soluble cavitand can be prepared from resorcinol in 13 working days.
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Affiliation(s)
- Simone Mosca
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA.,Department of Chemistry, The Scripps Research Institute, La Jolla, California, USA.,Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano, Italy
| | - Yang Yu
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA.,Department of Chemistry, The Scripps Research Institute, La Jolla, California, USA
| | - Julius Rebek
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA.,Department of Chemistry, The Scripps Research Institute, La Jolla, California, USA.,Department of Chemistry, Fudan University, Shanghai, China
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Alessandri I, Biavardi E, Gianoncelli A, Bergese P, Dalcanale E. Cavitands Endow All-Dielectric Beads With Selectivity for Plasmon-Free Enhanced Raman Detection of Nε-Methylated Lysine. ACS APPLIED MATERIALS & INTERFACES 2016; 8:14944-14951. [PMID: 26571376 DOI: 10.1021/acsami.5b08190] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
SiO2/TiO2 microbeads (T-rex) are promising materials for plasmon-free surface-enhanced Raman scattering (SERS), offering several key advantages in biodiagnostics. In this paper we report the combination of T-rex beads with tetraphosphonate cavitands (Tiiii), which imparts selectivity toward Nε-methylated lysine. SERS experiments demonstrated the efficiency and selectivity of the T-rex-Tiiii assays in detecting methylated lysine hydrochloride (Nε-Me-Lys-Fmoc) from aqueous solutions, even in the presence of the parent Lys-Fmoc hydrochloride as interferent. The negative results obtained in control experiments using TSiiii ruled out any other form of surface recognition or preferential physisorption. MALDI-TOF analyses on the beads exposed to Nε-Me-Lys-Fmoc revealed the presence of the Tiiii•Nε-Me-Lys-Fmoc complex. Raman analyses based on the intensity ratio of Nε-Me-Lys-Fmoc and cavitand-specific modes resulted in a dose-response plot, which allowed for estimating the concentration of Nε-methylated lysine from initial solutions in the 1 × 10(-3) to 1 × 10(-5) M range. These results can set the basis for the development of new Raman assays for epigenetic diagnostics.
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Affiliation(s)
- Ivano Alessandri
- INSTM and Chemistry for Technologies Laboratory, University of Brescia , via Branze 38, 25123 Brescia, Italy
| | - Elisa Biavardi
- Department of Chemistry and INSTM Ru, University of Parma , Parco area delle Scienze 17/A, 43124 Parma, Italy
| | - Alessandra Gianoncelli
- INSTM and Department of Molecular and Translational Medicine, University of Brescia , Viale Europa 11, 25123 Brescia, Italy
| | - Paolo Bergese
- INSTM and Department of Molecular and Translational Medicine, University of Brescia , Viale Europa 11, 25123 Brescia, Italy
| | - Enrico Dalcanale
- Department of Chemistry and INSTM Ru, University of Parma , Parco area delle Scienze 17/A, 43124 Parma, Italy
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Abstract
This review focuses on molecular containers formed by assembly processes driven by the hydrophobic effect, and summarizes the progress made in the field over the last ten years. This small but growing facet of supramolecular chemistry discusses three classes of molecules used by researchers to investigate how self-assembly can be applied to form discrete, mono-dispersed, and structurally well-defined supramolecular entities. The approaches demonstrate the importance of preorganization of arrays of rigid moieties to define a specific form predisposed to bind, fold, or assemble. As the examples demonstrate, studying these systems and their properties is teaching us how to control supramolecular chemistry in water, shedding light on aspects of aqueous solutions chemistry, and illustrating novel applications that harness the unique properties of the hydrophobic effect.
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Affiliation(s)
- Jacobs H Jordan
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA.
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Adriaenssens L, Acero Sánchez JL, Barril X, O'Sullivan CK, Ballester P. Binding of calix[4]pyrroles to pyridine N-oxides probed with surface plasmon resonance. Chem Sci 2014. [DOI: 10.1039/c4sc01745e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Kubitschke J, Javor S, Rebek J. Deep cavitand vesicles--multicompartmental hosts. Chem Commun (Camb) 2012; 48:9251-3. [PMID: 22875485 DOI: 10.1039/c2cc34065h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The synthesis and characterization of vesicles assembled from deep cavitands in water is reported. These vesicles act as hosts for three different types of guests: the cavitands bind small guest molecules, the bilayer attracts larger hydrophobic guests and the inner aqueous compartment contains hydrophilic molecules.
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Affiliation(s)
- Jens Kubitschke
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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