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Rubio-Camacho M, Martínez-Tomé MJ, Mira A, Mallavia R, Mateo CR. Formation of Multicolor Nanogels Based on Cationic Polyfluorenes and Poly(methyl vinyl ether-alt-maleic monoethyl ester): Potential Use as pH-Responsive Fluorescent Drug Carriers. Int J Mol Sci 2021; 22:9607. [PMID: 34502514 PMCID: PMC8431760 DOI: 10.3390/ijms22179607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/26/2021] [Accepted: 09/01/2021] [Indexed: 12/19/2022] Open
Abstract
In this study, we employed the copolymer poly(methyl vinyl ether-alt-maleic monoethyl ester) (PMVEMA-Es) and three fluorene-based cationic conjugated polyelectrolytes to develop fluorescent nanoparticles with emission in the blue, green and red spectral regions. The size, Zeta Potential, polydispersity, morphology, time-stability and fluorescent properties of these nanoparticles were characterized, as well as the nature of the interaction between both PMVEMA-Es and fluorescent polyelectrolytes. Because PMVEMA-Es contains a carboxylic acid group in its structure, the effects of pH and ionic strength on the nanoparticles were also evaluated, finding that the size is responsive to pH and ionic strength, largely swelling at physiological pH and returning to their initial size at acidic pHs. Thus, the developed fluorescent nanoparticles can be categorized as pH-sensitive fluorescent nanogels, since they possess the properties of both pH-responsive hydrogels and nanoparticulate systems. Doxorubicin (DOX) was used as a model drug to show the capacity of the blue-emitting nanogels to hold drugs in acidic media and release them at physiological pH, from changes in the fluorescence properties of both nanoparticles and DOX. In addition, preliminary studies by super-resolution confocal microscopy were performed, regarding their potential use as image probes.
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Affiliation(s)
| | - María José Martínez-Tomé
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández, 03202 Elche, Spain; (M.R.-C.); (A.M.); (R.M.)
| | | | | | - Carmen Reyes Mateo
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández, 03202 Elche, Spain; (M.R.-C.); (A.M.); (R.M.)
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2
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A conjugated polymer‐liposome complex: A contiguous water‐stable, electronic, and optical interface. VIEW 2020. [DOI: 10.1002/viw.20200081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Hossain S, Pai KR, Piyasena ME. Fluorescent Lipo-Beads for the Sensitive Detection of Phospholipase A 2 and Its Inhibitors. ACS Biomater Sci Eng 2020; 6:1989-1997. [PMID: 33455318 PMCID: PMC10012499 DOI: 10.1021/acsbiomaterials.9b01720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Phospholipase A2 (PLA2) is a membrane lytic enzyme that is present in many organisms. Human PLA2 has emerged as a potential biomarker as well as a therapeutic target for several diseases including cancer, cardiovascular diseases, and some inflammatory diseases. The current study focuses on the development of lipo-beads that are very reactive and highly sensitive to PLA2. To develop the best supported lipid bilayer formulation, several lipid combinations were investigated using 10 μm porous silica beads. The reactivity of PLA2 was monitored via the decrease in particle fluorescence because of the release of entrapped fluorescent dye from the particle pores or the disintegration of a fluorescent lipid constituted on the bilayer upon lipid hydrolysis using flow cytometry. The enzyme binding studies indicate that lipo-beads with bulky fluorescent tags in the lipid head group and anionic lipids produce a more pronounced response. The kinetic studies suggest that these lipo-beads are very reactive with PLA2 and can generate a detectable signal in less than 5 min. The enzyme inhibition studies were also conducted with two known PLA2 inhibitors, varespladib and quercetin. We find that quercetin can hydrolyze the supported membrane, and thus inhibition of PLA2 is not observed; however, varespladib has shown significant PLA2 inhibition on lipo-beads. We have demonstrated that our lipo-bead-based approach can detect annexin-3, a known disease biomarker, as low as 10 nM within 5 min after incubation.
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Affiliation(s)
- Shahriare Hossain
- Department of Chemistry, New Mexico Institute of Mining and Technology, 801, Leroy Place, Socorro, New Mexico 87801, United States
| | - Kalika R Pai
- Department of Chemistry, New Mexico Institute of Mining and Technology, 801, Leroy Place, Socorro, New Mexico 87801, United States
| | - Menake E Piyasena
- Department of Chemistry, New Mexico Institute of Mining and Technology, 801, Leroy Place, Socorro, New Mexico 87801, United States
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Kronfeld KP, Ellinger T, Köhler JM. Microfluidically prepared sensor particles for determination of chloride by fluorescence quenching of matrix-embedded lucigenin. SN APPLIED SCIENCES 2020. [DOI: 10.1007/s42452-020-2155-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Abstract
Polyacrylamide sensor particles have been synthesized by using a microfluidic arrangement for generation of microdroplets containing a reaction mixture for forming gel microparticles. The droplets are formed in an inert carrier liquid immiscible with the reaction mixture based on aqueous solutions. Gel particles are formed in situ by photochemical initiation of polymerization inside droplets using an UV-sensitive photoinitiator. In result, water-swellable spheres with submillimetre size are obtained. Those spheres were loaded with N,N′-dimethyl-9,9′-biacridinium dinitrate (lucigenin) as ion selective fluorescence probe for chloride. The particles can be dried, stored and re-swollen. Upon exposure of dried particles to sodium chloride solutions they showed dynamic fluorescence quenching obeying the linear plot of Stern–Volmer-equation between 0 and 130 mM Cl−. Thus, chloride concentrations up to 50 mM could be measured with appropriate accuracy. The particles allow a fast optical determination of chloride in tiny analyte volumes down to below ten microliters.
Graphic abstract
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Rubio-Camacho M, Alacid Y, Mallavia R, Martínez-Tomé MJ, Mateo CR. Polyfluorene-Based Multicolor Fluorescent Nanoparticles Activated by Temperature for Bioimaging and Drug Delivery. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:E1485. [PMID: 31635330 PMCID: PMC6835524 DOI: 10.3390/nano9101485] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 10/14/2019] [Accepted: 10/15/2019] [Indexed: 12/17/2022]
Abstract
Multifunctional nanoparticles have been attracting growing attention in recent years because of their capability to integrate materials with different features in one entity, which leads them to be considered as the next generation of nanomedicine. In this work, we have taken advantage of the interesting properties of conjugated polyelectrolytes to develop multicolor fluorescent nanoparticles with integrating imaging and therapeutic functionalities. With this end, thermosensitive liposomes were coated with three recently synthesized polyfluorenes: copoly-((9,9-bis(6'-N,N,N-trimethylammonium)hexyl)-2,7-(fluorene)-alt-1,4-(phenylene)) bromide (HTMA-PFP), copoly-((9,9-bis(6'-N,N,N-trimethylammonium)hexyl)-2,7-(fluorene)-alt-4,7-(2- (phenyl)benzo(d) (1,2,3) triazole)) bromide (HTMA-PFBT) and copoly-((9,9-bis(6'-N,N,N- trimethylammonium)hexyl)-2,7-(fluorene)-alt-1,4-(naphtho(2,3c)-1,2,5-thiadiazole)) bromide (HTMA-PFNT), in order to obtain blue, green and red fluorescent drug carriers, respectively. The stability, size and morphology of the nanoparticles, as well as their thermotropic behavior and photophysical properties, have been characterized by Dynamic Light Scattering (DLS), Zeta Potential, transmission electron microscope (TEM) analysis and fluorescence spectroscopy. In addition, the suitability of the nanostructures to carry and release their contents when triggered by hyperthermia has been explored by using carboxyfluorescein as a hydrophilic drug model. Finally, preliminary experiments with mammalian cells demonstrate the capability of the nanoparticles to mark and visualize cells with different colors, evidencing their potential use for imaging and therapeutic applications.
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Affiliation(s)
- Marta Rubio-Camacho
- Instituto de Investigación Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche (UMH), 03202 Elche, Alicante, Spain.
| | - Yolanda Alacid
- Instituto de Investigación Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche (UMH), 03202 Elche, Alicante, Spain.
| | - Ricardo Mallavia
- Instituto de Investigación Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche (UMH), 03202 Elche, Alicante, Spain.
| | - María José Martínez-Tomé
- Instituto de Investigación Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche (UMH), 03202 Elche, Alicante, Spain.
| | - C Reyes Mateo
- Instituto de Investigación Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche (UMH), 03202 Elche, Alicante, Spain.
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Park K, Shin EY, Jiao X, McNeill CR, Kim YH, Kwon SK, Noh YY. Effect of Backbone Sequence of a Naphthalene Diimide-Based Copolymer on Performance in n-Type Organic Thin-Film Transistors. ACS APPLIED MATERIALS & INTERFACES 2019; 11:35185-35192. [PMID: 31452373 DOI: 10.1021/acsami.9b09607] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report two newly synthesized naphthalene diimide (NDI)-based conjugated polymers, poly[(E)-2,7-bis(2-decyltetradecyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone-vinylene-thiophene-vinylene] (PNDI-VTV) and poly[(E)-2,7-bis(2-decyltetradecyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone-vinylene-selenophene-vinylene] (PNDI-VSV) with different donor units as electron-transporting organic semiconductors for organic field-effect transistors (OFETs). Furthermore, we study the effect of vinylene position on electron transport in the NDI polymers by using two similar polymers but with thiophene-vinylene-thiophene (PNDI-TVT) instead of vinylene-thiophene-vinylene or selenophene-vinylene-selenophene (PNDI-SVS) instead of vinylene-selenophene-vinylene. By incorporating vinylene between thiophene (or selenophene) units, the resulting NDI-based polymers PNDI-VTV and PNDI-VSV show larger backbone planarity than PNDI-TVT and PNDI-SVS. The polymers with a shorter acceptor monomer unit (PNDI-VTV and PNDI-VSV) show a strong face-on orientation, whereas those with a longer monomer unit (PNDI-TVT and SVS) exhibit a mixed face-on and edge-on orientation by two-dimensional grazing incidence X-ray diffraction. Optimized PNDI-VTV and PNDI-VSV OFETs exhibit electron mobilities of 0.043 and 0.7 cm2/(V·s), which is quite lower than those of PNDI-TVT and PNDI-SVS. In addition, the activation energies for electron transport of PNDI-VTV and PNDI-VSV were larger than those of PNDI-TVT and PNDI-SVS. Overall, this research provides the insight that the molecular alignment on the substrate can be controlled by the sequence of rigid acceptor monomer molecules for improving the electron transport of NDI polymers.
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Affiliation(s)
- Kwanghun Park
- Department of Materials Engineering and Convergence Technology and ERI , Gyeongsang National University , Jinju 660-701 , Republic of Korea
| | - Eul-Yong Shin
- Photo-electronic Hybrids Research Center , Korea Institute of Science and Technology , Seoul 02792 , Republic of Korea
| | - Xuechen Jiao
- Australian Synchrotron , ANSTO , 800 Blackburn Road , Clayton , Victoria 3168 , Australia
- Department of Materials Science and Engineering , Monash University , Wellington Road , Clayton , Victoria 3800 , Australia
| | - Christopher R McNeill
- Department of Materials Science and Engineering , Monash University , Wellington Road , Clayton , Victoria 3800 , Australia
| | - Yun-Hi Kim
- Department of Chemistry , Gyeongsang National University and RIGET , 900, Gajwa-dong , Jinju , Gyeongnam 660-701 , Republic of Korea
| | - Soon-Ki Kwon
- Department of Materials Engineering and Convergence Technology and ERI , Gyeongsang National University , Jinju 660-701 , Republic of Korea
| | - Yong-Young Noh
- Department of Chemical Engineering , Pohang University of Science and Technology , 77 Chengam-Ro , Nam-Gu, Pohang , 37673 , Republic of Korea
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Vázquez-Guilló R, Martínez-Tomé MJ, Kahveci Z, Torres I, Falco A, Mallavia R, Mateo CR. Synthesis and Characterization of a Novel Green Cationic Polyfluorene and Its Potential Use as a Fluorescent Membrane Probe. Polymers (Basel) 2018; 10:E938. [PMID: 30960863 PMCID: PMC6404094 DOI: 10.3390/polym10090938] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/06/2018] [Accepted: 08/20/2018] [Indexed: 12/12/2022] Open
Abstract
In the present work, we have synthesized a novel green-emitter conjugated polyelectrolyte Copoly-{[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]-2,7-(fluorene)-alt-4,7-(2-(phenyl) benzo[d] [1,2,3] triazole)} bromide (HTMA-PFBT) by microwave-assisted Suzuki coupling reaction. Its fluorescent properties have been studied in aqueous media and in presence of model membranes of different composition, in order to explore its ability to be used as a green fluorescent membrane probe. The polyelectrolyte was bound with high affinity to the membrane surface, where it exhibited high fluorescence efficiency and stability. HTMA-PFBT showed lower affinity to zwitterionic membranes as compared to anionic ones, as well as a more external location, near the membrane-aqueous interface. Fluorescence microscopy studies confirmed the interaction of HTMA-PFBT with the model membranes, labelling the lipid bilayer without perturbing its morphology and showing a clear preference towards anionic systems. In addition, the polyelectrolyte was able to label the membrane of bacteria and living mammalian cells, separately. Finally, we explored if the polyelectrolyte can function also as a sensitive probe able of detecting lipid-phase transitions. All these results suggest the potential use of HTMA-PFBT as a green membrane marker for bioimaging and selective recognition of bacteria cell over mammalian ones and as a tool to monitor changes in physical state of lipid membranes.
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Affiliation(s)
- Rebeca Vázquez-Guilló
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elche, Spain.
| | | | - Zehra Kahveci
- Living Systems Institute, University of Exeter, Exeter EX4 4QD, UK.
| | - Ivan Torres
- Departamento de Química Inorgánca, Orgánica y Bioqímica, Universidad de Castilla la Mancha, 13071 Cuidad Real, Spain.
| | - Alberto Falco
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elche, Spain.
| | - Ricardo Mallavia
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elche, Spain.
| | - C Reyes Mateo
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elche, Spain.
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8
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Qi Y, Xu W, Kang R, Ding N, Wang Y, He G, Fang Y. Discrimination of saturated alkanes and relevant volatile compounds via the utilization of a conceptual fluorescent sensor array based on organoboron-containing polymers. Chem Sci 2018; 9:1892-1901. [PMID: 29675235 PMCID: PMC5890797 DOI: 10.1039/c7sc05243j] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 01/05/2018] [Indexed: 12/17/2022] Open
Abstract
A conceptual sensor array for the efficient discrimination and fast detection of saturated alkanes and commonly found volatile solvents is reported.
This work reports a conceptual sensor array for the highly discriminative analysis of 20 clinically and environmentally relevant volatile small organic molecules (VSOMs), including saturated alkanes and common solvents, in the air at room temperature. For the construction of the sensor array, a four coordinated, non-planar mono-boron complex and four relevant polymers are synthesized. Based on the polymers and the use of different substrates, 8 fluorescent films have been fabricated. Integration of the film-based sensors results in the sensor array, which demonstrates unprecedented discriminating capability toward the VSOMs. Moreover, for the signal molecule of lung cancer, n-pentane, the response time is less than 1 s, the experimental detection limit is lower than 3.7 ppm, and after repeating the tests over 50 times no observable degradation was observed. The superior sensing performance is partially ascribed to the tetrahedral structure of the boron centers in the polymers as it may produce molecular channels in the films, which are a necessity for fast and reversible sensing. In addition, the polarity of the micro-channels may endow the films with additional selectivity towards the analytes. The design as demonstrated provides an effective strategy to improve the sensing performance of fluorescent films to very challenging analytes, such as saturated alkanes.
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Affiliation(s)
- Yanyu Qi
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education , School of Chemistry and Chemical Engineering , Shaanxi Normal University , Xi'an 710062 , P. R. China .
| | - Wenjun Xu
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education , School of Chemistry and Chemical Engineering , Shaanxi Normal University , Xi'an 710062 , P. R. China .
| | - Rui Kang
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education , School of Chemistry and Chemical Engineering , Shaanxi Normal University , Xi'an 710062 , P. R. China .
| | - Nannan Ding
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education , School of Chemistry and Chemical Engineering , Shaanxi Normal University , Xi'an 710062 , P. R. China .
| | - Yelei Wang
- School of Physics and Information Technology , Shaanxi Normal University , Xi'an 710062 , P. R. China
| | - Gang He
- Center for Materials Chemistry , Frontier Institute of Science and Technology , Xi'an Jiaotong University , Xi'an , 710054 , P. R. China
| | - Yu Fang
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education , School of Chemistry and Chemical Engineering , Shaanxi Normal University , Xi'an 710062 , P. R. China .
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9
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Mazur F, Bally M, Städler B, Chandrawati R. Liposomes and lipid bilayers in biosensors. Adv Colloid Interface Sci 2017; 249:88-99. [PMID: 28602208 DOI: 10.1016/j.cis.2017.05.020] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/30/2017] [Indexed: 10/19/2022]
Abstract
Biosensors for the rapid, specific, and sensitive detection of analytes play a vital role in healthcare, drug discovery, food safety, and environmental monitoring. Although a number of sensing concepts and devices have been developed, many longstanding challenges to obtain inexpensive, easy-to-use, and reliable sensor platforms remain largely unmet. Nanomaterials offer exciting possibilities for enhancing the assay sensitivity and for lowering the detection limits down to single-molecule resolution. In this review, we present an overview of liposomes and lipid bilayers in biosensing applications. Lipid assemblies in the form of spherical liposomes or two-dimensional planar membranes have been widely used in the design of biosensing assays; in particular, we highlight a number of recent promising developments of biosensors based on liposomes in suspension, liposome arrays, and lipid bilayers arrays. Assay sensitivity and specificity are discussed, advantages and drawbacks are reviewed, and possible further developments are outlined.
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Abstract
Each year, the United States spends about $20 billion to treat people who have been infected with antibiotic resistant bacteria. Even so, the development of new antibiotics has slowed considerably since the mid-20th century. As a result, researchers are looking into developing synthetic compounds and materials with antimicrobial activities such as those made by the Schanze and Whitten groups [ACS Appl. Mater. Interfaces 3, 2820 (2011)]. Previously, they have demonstrated that poly(phenylene ethynylene) (PPE) based electrolytes and oligomeric end-only phenylene ethynylene (EO-OPE) based electrolytes possess strong biocidal activity. However, before the PPE and OPE can be used with humans, skin irritation tests are required to ensure their safety. In this work, in vitro skin assays are used to predict in vivo irritation. Tissues were conditioned for 24 h, exposed to test substances for 1 h, and then tested for viability using colorimetric and cytokine assays. Concentrations up to 50 μg/ml were tested. Viability assays and cytokine (IL-1α) assays demonstrated that the two polymers, three symmetric oligomers, and three "end only" oligomers were nonirritants. In addition, electrospun mats consisting of several promising compounds, including poly(caprolactone), were evaluated. Therefore, all test substances are conservatively classified as nonirritants after a 1 h exposure time period.
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11
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Houston JE, Kraft M, Mooney I, Terry AE, Scherf U, Evans RC. Charge-Mediated Localization of Conjugated Polythiophenes in Zwitterionic Model Cell Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:8141-8153. [PMID: 27434827 DOI: 10.1021/acs.langmuir.6b01828] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The selective engineering of conjugated polyelectrolyte (CPE)-phospholipid interfaces is poised to play a key role in the design of advanced biomedical and biotechnological devices. Herein, we report a strategic study to investigate the relationship between the charge of the CPE side group and their association with zwitterionic phospholipid bilayers. The interaction of dipalmitoylphosphatidylcholine (DPPC) phospholipid vesicles with a series of poly(thiophene)s bearing zwitterionic, cationic, or anionic terminal groups (P3Zwit, P3TMAHT and P3Anionic, respectively) has been probed. Although all CPEs showed an affinity for the zwitterionic vesicles, the calculated partition coefficients determined using photoluminescence spectroscopy suggested preferential incorporation within the lipid bilayer in the order P3Zwit > P3Anionic ≫ P3TMAHT. The polarity probe Prodan was used to further qualify the position of the CPE inside the vesicle bilayers via Förster resonance energy transfer (FRET) studies. The varying proximity of the CPEs to Prodan was reflected in the Stern-Volmer quenching constants and decreased in the order P3Anionic > P3TMAHT ≫ P3Zwit. Dynamic light scattering measurements showed an increase in the hydrodynamic diameter of the DPPC vesicles upon addition of each poly(thiophene), but to the greatest extent for P3Anionic. Small-angle neutron scattering studies also revealed that P3Anionic specifically increased the thickness of the headgroup region of the phospholipid bilayer. Epifluorescence and atomic force microscopy imaging showed that P3TMAHT formed amorphous agglomerates on the vesicle surface, P3Zwit was buried throughout the bilayer, and P3Anionic formed a shell of protruding chains around the surface, which promoted vesicle fusion. The global data indicate three distinctive modes of interaction for the poly(thiophene)s within DPPC vesicles, whereby the nature of the association is ultimately controlled by the pendant charge group on each CPE chain. Our results suggest that charge-mediated self-assembly may provide a simple and effective route to design luminescent CPE probes capable of specific localization within phospholipid membranes.
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Affiliation(s)
- Judith E Houston
- School of Chemistry and CRANN, University of Dublin, Trinity College , College Green, Dublin 2, Ireland
| | - Mario Kraft
- Macromolecular Chemistry Group (Buwmakro) and Institute for Polymer Technology, Bergische Universität Wuppertal , Gauss-Str. 20, D-42119 Wuppertal, Germany
| | - Ian Mooney
- School of Chemistry and CRANN, University of Dublin, Trinity College , College Green, Dublin 2, Ireland
| | - Ann E Terry
- ISIS, STFC, Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX, U.K
| | - Ullrich Scherf
- Macromolecular Chemistry Group (Buwmakro) and Institute for Polymer Technology, Bergische Universität Wuppertal , Gauss-Str. 20, D-42119 Wuppertal, Germany
| | - Rachel C Evans
- School of Chemistry and CRANN, University of Dublin, Trinity College , College Green, Dublin 2, Ireland
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Kahveci Z, Vázquez-Guilló R, Martínez-Tomé MJ, Mallavia R, Mateo CR. New Red-Emitting Conjugated Polyelectrolyte: Stabilization by Interaction with Biomolecules and Potential Use as Drug Carriers and Bioimaging Probes. ACS APPLIED MATERIALS & INTERFACES 2016; 8:1958-1969. [PMID: 26709951 DOI: 10.1021/acsami.5b10167] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The design and development of fluorescent conjugated polyelectrolytes (CPEs) emitting in the red region of the visible spectrum is at present of great interest for bioimaging studies. However, despite the wide variety of CPEs available, stable bright red-emitters remain scarce due to their low solubility and instability in aqueous media, consequently limiting their applications. In this work, we have synthesized and characterized a new red-emitting cationic conjugated polyelectrolyte copoly-{[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]-2,7-(fluorene)-alt-1,4-(naphtho[2,3c]-1,2,5-thiadiazole)} bromide (HTMA-PFNT), based on the incorporation of naphtha[2,3c][1,2,5] thiadiazole on fluorene backbone to increase the bathochromic emission, extending the conjugation length in the polymer backbone. Water stabilization was achieved by binding the polyelectrolyte to two different biological systems which are currently used as nanocarriers: human serum albumin (HSA) and lipid vesicles. Using both systems, stable nanostructures of different composition were obtained and their properties were characterized. The properties of the protein-based nanoparticles are consistent with polyelectrolyte aggregates covered with HSA molecules, while the liposome system is composed of lipid vesicles coated with polyelectrolyte chains partially inserted in the bilayer. Both protein and vesicle structural integrity were not affected after their interaction with HTMA-PFNT, as well as the carrier properties, allowing for the binding and transport of ligands. In addition, the nanoparticles displayed the ability of labeling the cell membrane of living cells. All these results extend the potential applications of these novel multifunctional nanoparticles as therapeutic carriers and bioimaging probes.
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Affiliation(s)
- Zehra Kahveci
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández , 03202 Elche, Alicante, Spain
| | - Rebeca Vázquez-Guilló
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández , 03202 Elche, Alicante, Spain
| | - Maria José Martínez-Tomé
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández , 03202 Elche, Alicante, Spain
| | - Ricardo Mallavia
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández , 03202 Elche, Alicante, Spain
| | - C Reyes Mateo
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández , 03202 Elche, Alicante, Spain
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Li J, Zhang Y, Ai J, Gao Q, Qi H, Zhang C, Cheng Z. Quantum dot cluster (QDC)-loaded phospholipid micelles as a FRET probe for phospholipase A 2 detection. RSC Adv 2016; 6:15895-15899. [PMID: 26998254 PMCID: PMC4792299 DOI: 10.1039/c5ra25292j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
A simple assay for phospholipase A2 (PLA2) enzyme was developed based on a fluorescence resonance energy transfer (FRET) probe using the quantum dot cluster (QDC)-loaded phospholipid micelles. The probe was prepared by encapsulating many small hydrophobic quantum dots (QDs) within the hydrophobic core of micelles that were formed from the coassembly of hydrogenated soy phosphatidylcholine phospholipids (HSPC) and fluorescent lipids (NBD-PC). QDCs formed within the micelle core served as the substrate for NBD fluorescence quenching through FRET. The QDC-loaded micelles showed very low background fluorescence. As the PLA2 enzyme selectively digested lipids, the NBD fluorescence was recovered from its quenched state, leading to the sensitive detection of PLA2. This assay provided a limit of detection (at a signal-to-noise ratio of 3) of 3 U/L for PLA2. In the presence of a PLA2 inhibitor, the fluorescent response of the sensor for PLA2 decreased, indicating that the assay could also be used for screening the PLA2 inhibitors.
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Affiliation(s)
- Junling Li
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710062, China
| | - Yonghua Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710062, China
| | - Junjie Ai
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710062, China
| | - Qiang Gao
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710062, China
| | - Honglan Qi
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710062, China
| | - Chengxiao Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710062, China
| | - Zhiliang Cheng
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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14
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Kahveci Z, Vázquez-Guilló R, Mira A, Martinez L, Falcó A, Mallavia R, Mateo CR. Selective recognition and imaging of bacterial model membranes over mammalian ones by using cationic conjugated polyelectrolytes. Analyst 2016; 141:6287-6296. [DOI: 10.1039/c6an01427e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This work describes the use of cationic polyfluorenes as fluorescent markers to selectively recognize bacterial membranes.
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Affiliation(s)
- Z. Kahveci
- Instituto de Biología Molecular y Celular
- Universidad Miguel Hernández
- 03202 Elche
- Spain
| | - R. Vázquez-Guilló
- Instituto de Biología Molecular y Celular
- Universidad Miguel Hernández
- 03202 Elche
- Spain
| | - A. Mira
- Instituto de Biología Molecular y Celular
- Universidad Miguel Hernández
- 03202 Elche
- Spain
| | - L. Martinez
- Instituto de Biología Molecular y Celular
- Universidad Miguel Hernández
- 03202 Elche
- Spain
| | - A. Falcó
- Instituto de Biología Molecular y Celular
- Universidad Miguel Hernández
- 03202 Elche
- Spain
| | - R. Mallavia
- Instituto de Biología Molecular y Celular
- Universidad Miguel Hernández
- 03202 Elche
- Spain
| | - C. R. Mateo
- Instituto de Biología Molecular y Celular
- Universidad Miguel Hernández
- 03202 Elche
- Spain
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15
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Darwish GH, Karam P. Nanohybrid conjugated polyelectrolytes: highly photostable and ultrabright nanoparticles. NANOSCALE 2015; 7:15149-15158. [PMID: 26255590 DOI: 10.1039/c5nr03299g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a general and straightforward one-step approach to enhance the photophysical properties of conjugated polyelectrolytes. Upon complexation with an amphiphilic polymer (polyvinylpyrrolidone), an anionic conjugated polyelectrolyte (poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene]) was prepared into small nanoparticles with exceptional photostability and brightness. The polymer fluorescence intensity was enhanced by 23 -fold and could be easily tuned by changing the order of addition. Single molecule experiments revealed a complete suppression of blinking. In addition, after only losing 18% of the original intensity, a remarkable amount of photons were emitted per particle (∼10(9), on average). This number is many folds greater than popular organic fluorescent dyes. We believe that an intimate contact between the two polymers is shielding the conjugated polyelectrolyte from the destructive photooxidation. The prepared nanohybrid particles will prove instrumental in single particle based fluorescent assays and can serve as a probe for the current state-of-the-art bioimaging fluorescence techniques.
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Affiliation(s)
- Ghinwa H Darwish
- Department of Chemistry, American University of Beirut, P.O. Box 11-0236, Beirut, Lebanon.
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16
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Liu Z, Long T, Wu S, Li C. Porphyrin-loaded liposomes and graphene oxide used for the membrane pore-forming protein assay and inhibitor screening. Analyst 2015; 140:5495-500. [PMID: 26160270 DOI: 10.1039/c5an00699f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The interaction of planar aromatic molecules with the graphene oxide (GO) sheets is often marked by the fluorescence quenching of the former. Here, the α,β,γ,δ-tetrakis[4-(trimethylammoniumyl)phenyl]porphyrin (TAPP) molecules and the GO, corresponding to the energy donor and the acceptor respectively, are initially separated by encapsulating the TAPP molecules within the liposomes, to obstruct the formation of the self-assembled energy transfer-based quenching system. Upon disruption of the liposome membranes by the PLA2 or the α-toxin, the encapsulated TAPP molecules are released and subsequently result in significant fluorescence changes. Thus, a platform based on the fluorescence signal for monitoring the activity of the membrane pore-forming protein with advantages of high sensitivity and commonality was established. Using this strategy, we can detect the PLA2 and the α-toxin concentrations as low as 200 pM and 9.0 nM, respectively. Furthermore, by taking chlorpromazine and baicalin as the examples, we use the assay to evaluate the prohibition effects on the PLA2 and the α-toxin, and the IC50 values of chlorpromazine toward the PLA2 (9.6 nM) and that of baicalin toward the α-toxin (289.2 nM) were found to be 12.0 ± 0.62 μM and 26.9 ± 2.6 μM, respectively.
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Affiliation(s)
- Zhongde Liu
- Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China.
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17
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Chapman R, Lin Y, Burnapp M, Bentham A, Hillier D, Zabron A, Khan S, Tyreman M, Stevens MM. Multivalent nanoparticle networks enable point-of-care detection of human phospholipase-A2 in serum. ACS NANO 2015; 9:2565-2573. [PMID: 25756526 PMCID: PMC5407437 DOI: 10.1021/nn5057595] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A rapid and highly sensitive point-of-care (PoC) lateral flow assay for phospholipase A2 (PLA2) is demonstrated in serum through the enzyme-triggered release of a new class of biotinylated multiarmed polymers from a liposome substrate. Signal from the enzyme activity is generated by the adhesion of polystreptavidin-coated gold nanoparticle networks to the lateral flow device, which leads to the appearance of a red test line due to the localized surface plasmon resonance effect of the gold. The use of a liposome as the enzyme substrate and multivalent linkers to link the nanoparticles leads to amplification of the signal, as the cleavage of a small amount of lipids is able to release a large amount of polymer linker and adhesion of an even larger amount of gold nanoparticles. By optimizing the molecular weight and multivalency of these biotinylated polymer linkers, the sensitivity of the device can be tuned to enable naked-eye detection of 1 nM human PLA2 in serum within 10 min. This high sensitivity enabled the correct diagnosis of pancreatitis in diseased clinical samples against a set of healthy controls using PLA2 activity in a point-of-care device for the first time.
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Affiliation(s)
- Robert Chapman
- Department of Materials, Department of Bioengineering and Institute for Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Yiyang Lin
- Department of Materials, Department of Bioengineering and Institute for Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Mark Burnapp
- Mologic Ltd, Bedford Technology Park, Thurleigh, Bedfordshire, MK44 2YP, UK
| | - Andrew Bentham
- Mologic Ltd, Bedford Technology Park, Thurleigh, Bedfordshire, MK44 2YP, UK
| | - David Hillier
- Hepatology and Gastroenterology Section, Faculty of Medicine, St Mary's Hospital Campus, Imperial College London, London, W2 1NY, UK
| | - Abigail Zabron
- Hepatology and Gastroenterology Section, Faculty of Medicine, St Mary's Hospital Campus, Imperial College London, London, W2 1NY, UK
| | - Shahid Khan
- Hepatology and Gastroenterology Section, Faculty of Medicine, St Mary's Hospital Campus, Imperial College London, London, W2 1NY, UK
| | - Matthew Tyreman
- Mologic Ltd, Bedford Technology Park, Thurleigh, Bedfordshire, MK44 2YP, UK
| | - Molly M. Stevens
- Department of Materials, Department of Bioengineering and Institute for Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
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18
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Tapia MJ, Monteserín M, Burrows HD, Almeida JAS, Pais AACC, Pina J, Seixas de Melo JS, Jarmelo S, Estelrich J. From molecular modelling to photophysics of neutral oligo- and polyfluorenes incorporated into phospholipid bilayers. SOFT MATTER 2015; 11:303-317. [PMID: 25411076 DOI: 10.1039/c4sm02145b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The combination of various experimental techniques with theoretical simulations has allowed elucidation of the mode of incorporation of fluorene based derivatives into phospholipid bilayers. Molecular dynamics (MD) simulations on a fully hydrated 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) bilayer, with benzene (B), biphenyl (BP), fluorene (F) and tri-(9,9-di-n-octylfluorenyl-2,7-diyl), TF, have provided insights into the topography of these molecules when they are present in the phospholipid bilayer, and suggest marked differences between the behavior of the small molecules and the oligomer. Further information on the interaction of neutral fluorenes within the phospholipid bilayer was obtained by an infrared (IR) spectroscopic study of films of DMPC and of the phospholipid with PFO deuterated specifically on its alkyl chains (DMPC-PFO-d34). This was complemented by measurements of the effect of F, TF and two neutral polymers: polyfluorene poly(9,9-di-n-octylfluorenyl-2,7-diyl), PFO, and poly(9,9-di-n-dodecylfluorenyl-2,7-diyl), PFD, on the phospholipid phase transition temperature using differential scanning calorimetry (DSC). Changes in liposome size upon addition of F and PFO were followed by dynamic light scattering. In addition, the spectroscopic properties of F, TF, PFO and PFD solubilised in DMPC liposomes (absorption, steady-state and time-resolved fluorescence) were compared with those of the same probes in typical organic solvents (chloroform, cyclohexane and ethanol). Combining the insight from MD simulations with the results at the molecular level from the various experimental techniques suggests that while the small molecules have a tendency to be located in the phospholipid head group region, the polymers are incorporated within the lipid bilayers, with the backbone predominantly orthogonal to the phospholipid alkyl chains and with interdigitation of them and the PFO alkyl chains.
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Affiliation(s)
- M J Tapia
- Departamento de Química, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001 Burgos, Spain.
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19
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Cheng Z, Tsourkas A. Monitoring phospholipase A₂ activity with Gd-encapsulated phospholipid liposomes. Sci Rep 2014; 4:6958. [PMID: 25376186 PMCID: PMC4223643 DOI: 10.1038/srep06958] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/21/2014] [Indexed: 11/23/2022] Open
Abstract
To date, numerous analytical methods have been developed to monitor phospholipase A2 (PLA2) activity. However, many of these methods require the use of unnatural PLA2 substrates that may alter enzyme kinetics, and probes that cannot be extended to applications in more complex environments. It would be desirable to develop a versatile assay that monitors PLA2 activity based on interactions with natural phospholipids in complex biological samples. Here, we developed an activatable T1 magnetic resonance (MR) imaging contrast agent to monitor PLA2 activity. Specifically, the clinically approved gadolinium (Gd)-based MR contrast agent, gadoteridol, was encapsulated within nanometer-sized phospholipid liposomes. The encapsulated Gd exhibited a low T1-weighted signal, due to low membrane permeability. However, when the phospholipids within the liposomal membrane were hydrolyzed by PLA2, encapsulated Gd was released into bulk solution, resulting in a measureable change in the T1-relaxation time. These activatable MR contrast agents can potentially be used as nanosensors for monitoring of PLA2 activity in biological samples with minimal sample preparation.
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Affiliation(s)
- Zhiliang Cheng
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Andrew Tsourkas
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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20
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Wu D, Schanze KS. Protein induced aggregation of conjugated polyelectrolytes probed with fluorescence correlation spectroscopy: application to protein identification. ACS APPLIED MATERIALS & INTERFACES 2014; 6:7643-7651. [PMID: 24766222 DOI: 10.1021/am5009437] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The interaction of a series of water-soluble conjugated polyelectrolytes with varying backbone structure, charge type (cationic and anionic), and charge density with a set of seven different proteins is explored by using fluorescence correlation spectroscopy (FCS). The FCS method affords the diffusion time for a particular CPE/protein pair, and this diffusion time is a reflection of the aggregation state of the polymer/protein in the solution. The diffusion time is larger for oppositely charged CPE/protein combinations, reflecting the tendency toward the formation of CPE/protein aggregates in these systems. However, by careful analysis of the data, other factors emerge, including possible effects of hydrophobic interaction in specific CPE/protein systems. The final diffusion time for each CPE/protein mixture varies and the diffusion time response pattern created by the six-CPE array for a typical protein is unique, and this effect was leveraged to develop a sensor array for protein identification by using linear-discriminant analysis (LDA) methods. By application of multimode linear discrimination analysis, the unknown protein samples have been successfully identified with a total accuracy of 93%.
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Affiliation(s)
- Danlu Wu
- Department of Chemistry, University of Florida , Gainesville, Florida 32611-7200, United States
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21
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Kahveci Z, Martínez-Tomé MJ, Esquembre R, Mallavia R, Mateo CR. Selective Interaction of a Cationic Polyfluorene with Model Lipid Membranes: Anionic versus Zwitterionic Lipids. MATERIALS 2014; 7:2120-2140. [PMID: 28788559 PMCID: PMC5453277 DOI: 10.3390/ma7032120] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 02/19/2014] [Accepted: 03/04/2014] [Indexed: 12/20/2022]
Abstract
This paper explores the interaction mechanism between the conjugated polyelectrolyte {[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]fluorene-phenylene}bromide (HTMA-PFP) and model lipid membranes. The study was carried out using different biophysical techniques, mainly fluorescence spectroscopy and microscopy. Results show that despite the preferential interaction of HTMA-PFP with anionic lipids, HTMA-PFP shows affinity for zwitterionic lipids; although the interaction mechanism is different as well as HTMA-PFP's final membrane location. Whilst the polyelectrolyte is embedded within the lipid bilayer in the anionic membrane, it remains close to the surface, forming aggregates that are sensitive to the physical state of the lipid bilayer in the zwitterionic system. The different interaction mechanism is reflected in the polyelectrolyte fluorescence spectrum, since the maximum shifts to longer wavelengths in the zwitterionic system. The intrinsic fluorescence of HTMA-PFP was used to visualize the interaction between polymer and vesicles via fluorescence microscopy, thanks to its high quantum yield and photostability. This technique allows the selectivity of the polyelectrolyte and higher affinity for anionic membranes to be observed. The results confirmed the appropriateness of using HTMA-PFP as a membrane fluorescent marker and suggest that, given its different behaviour towards anionic and zwitterionic membranes, HTMA-PFP could be used for selective recognition and imaging of bacteria over mammalian cells.
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Affiliation(s)
- Zehra Kahveci
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante) 03202, Spain.
| | - María José Martínez-Tomé
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante) 03202, Spain.
| | - Rocío Esquembre
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante) 03202, Spain.
| | - Ricardo Mallavia
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante) 03202, Spain.
| | - C Reyes Mateo
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Elche (Alicante) 03202, Spain.
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22
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Lee GS, Park JW. Effect of Vesicle Curvature on Phospholipase D Reaction-Induced-Rupture. B KOREAN CHEM SOC 2013. [DOI: 10.5012/bkcs.2013.34.11.3223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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23
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Quantum dot–NBD–liposome luminescent probes for monitoring phospholipase A2 activity. Anal Bioanal Chem 2013; 405:9729-37. [DOI: 10.1007/s00216-013-7422-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 07/30/2013] [Accepted: 10/07/2013] [Indexed: 11/26/2022]
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24
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Wilde KN, Whitten DG, Canavan HE. In vitro cytotoxicity of antimicrobial conjugated electrolytes: interactions with mammalian cells. ACS APPLIED MATERIALS & INTERFACES 2013; 5:9305-11. [PMID: 24102342 DOI: 10.1021/am402476g] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
An estimated 19 000 deaths and $3-4 billion in health care costs per year in the United States are attributed to methicillin-resistant Staphlococcus aureus (MRSA) infections. Certain conjugated phenylene ethynylene (CPE)-based polymers (PPE) and oligomers (OPE) have been demonstrated to exhibit dark and light-activated antimicrobial activity. Until recently, the relative cytotoxicity of these PPEs and OPEs toward mammalian cells haas been unknown, limiting the applications for which they may be used (e.g., reducing and/or preventing the spread of untreatable bacterial strains). In this work, we examine the toxicity of CPEs to mammalian cells using cytotoxicity assays of cellular monolayers. Eight CPEs, two PPEs and six OPEs, were selected for these studies based on their biocidal activity, and diversity of repeat unit number and functional groups. Briefly, two cell types were exposed to CPEs at concentrations ranging from 1-100 ug/mL for 24 h. We find that concentration largely determines the resulting viability of cells, although at intermediate concentrations (5-10 ug/mL), the effect of light on light-activated compounds is very important. Furthermore, we find that the longer-chained compounds are cytotoxic at much higher concentrations, and therefore have the widest range of concentrations available for potential applications.
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Affiliation(s)
- Kristin N Wilde
- Center for Biomedical Engineering, Department of Chemical and Nuclear Engineering, MSC01-1141, University of New Mexico , Albuquerque, New Mexico 87131, United States
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25
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Kahveci Z, Martínez-Tomé MJ, Mallavia R, Mateo CR. Use of the Conjugated Polyelectrolyte Poly{[9,9-bis(6′-N,N,N-trimethylammonium)hexyl]fluorene-phenylene} Bromide (HTMA-PFP) as a Fluorescent Membrane Marker. Biomacromolecules 2013; 14:1990-8. [DOI: 10.1021/bm400348n] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Zehra Kahveci
- Instituto de Biología Molecular
y Celular, Universidad Miguel Hernández, 03202 Elche, Spain
| | | | - Ricardo Mallavia
- Instituto de Biología Molecular
y Celular, Universidad Miguel Hernández, 03202 Elche, Spain
| | - C. Reyes Mateo
- Instituto de Biología Molecular
y Celular, Universidad Miguel Hernández, 03202 Elche, Spain
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26
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Correlation between composition of the outer layer and phase asymmetry for vesicles ruptured by phospholipase D. J Membr Biol 2013; 246:399-405. [PMID: 23644991 DOI: 10.1007/s00232-013-9551-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 04/19/2013] [Indexed: 10/26/2022]
Abstract
Spherical phospholipid bilayers, vesicles, were prepared by using the layer-by-layer double emulsion technique, which allows individual layers to be formed asymmetrically. Phases of the layers were adjusted by selecting the lipid tail group. The head group composition of the vesicle outer layer varied 0-100 % of phosphatidylcholine (PC) by 10 % under the condition that the diameter of the vesicle was kept constant. On the outer layer of the vesicle, the phospholipase D (PLD) reacted to convert PC to phosphatidic acid. The reaction induced a curvature change of the vesicles, which eventually led them to rupture. Response time from the PLD injection to the rupture was measured against the different compositions of the outer layer at each phase (solid and liquid) using the fluorescence intensity change of pH-sensitive dye encapsulated in the vesicles. From this measurement, the rupture caused by the PLD reaction was analyzed with respect to the phase asymmetry of the layers and the composition of the outer layer. These results were interpreted with the lipid density and stability of the layers. It was observed that the solid phase of the outer layer had a variance in response time according to the phase of the inner layer, whereas the liquid phase did not. Additionally, the response of the solid phase of the outer layer at the liquid phase of the inner layer was faster than at the solid phase of the inner layer as a result of its stability.
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27
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Sasaki DY, Zawada N, Gilmore SF, Narasimmaraj P, Sanchez MAA, Stachowiak JC, Hayden CC, Wang HL, Parikh AN, Shreve AP. Lipid membrane domains for the selective adsorption and surface patterning of conjugated polyelectrolytes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:5214-5221. [PMID: 23544969 DOI: 10.1021/la400454c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Conjugated polyelectrolytes (CPEs) are promising materials for generating optoelectronics devices under environmentally friendly processing conditions, but challenges remain to develop methods to define lateral features for improved junction interfaces and direct optoelectronic pathways. We describe here the potential to use a bottom-up approach that employs self-assembly in lipid membranes to form structures to template the selective adsorption of CPEs. Phase separation of gel phase anionic lipids and fluid phase phosphocholine lipids allowed the formation of negatively charged domain assemblies that selectively adsorb a cationic conjugated polyelectrolyte (P2). Spectroscopic studies found the adsorption of P2 to negatively charged membranes resulted in minimal structural change of the solution phase polymer but yielded an enhancement in fluorescence intensity (~50%) due to loss of quenching pathways. Fluorescence microscopy, dynamic light scattering, and AFM imaging were used to characterize the polymer-membrane interaction and the polymer-bound domain structures of the biphasic membranes. In addition to randomly formed circular gel phase domains, we also show that predefined features, such as straight lines, can be directed to form upon etched patterns on the substrate, thus providing potential routes toward the self-organization of optoelectronic architectures.
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Affiliation(s)
- Darryl Y Sasaki
- Sandia National Laboratories, Livermore, California 94550, USA.
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28
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Clark APZ, Shi C, Ng BC, Wilking JN, Ayzner AL, Stieg AZ, Schwartz BJ, Mason TG, Rubin Y, Tolbert SH. Self-assembling semiconducting polymers--rods and gels from electronic materials. ACS NANO 2013; 7:962-977. [PMID: 23346927 DOI: 10.1021/nn304437k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In an effort to favor the formation of straight polymer chains without crystalline grain boundaries, we have synthesized an amphiphilic conjugated polyelectrolyte, poly(fluorene-alt-thiophene) (PFT), which self-assembles in aqueous solutions to form cylindrical micelles. In contrast to many diblock copolymer assemblies, the semiconducting backbone runs parallel, not perpendicular, to the long axis of the cylindrical micelle. Solution-phase micelle formation is observed by X-ray and visible light scattering. The micelles can be cast as thin films, and the cylindrical morphology is preserved in the solid state. The effects of self-assembly are also observed through spectral shifts in optical absorption and photoluminescence. Solutions of higher-molecular-weight PFT micelles form gel networks at sufficiently high aqueous concentrations. Rheological characterization of the PFT gels reveals solid-like behavior and strain hardening below the yield point, properties similar to those found in entangled gels formed from surfactant-based micelles. Finally, electrical measurements on diode test structures indicate that, despite a complete lack of crystallinity in these self-assembled polymers, they effectively conduct electricity.
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Affiliation(s)
- Andrew P-Z Clark
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, USA
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29
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Effect of mixed-phospholipid layer on phospholipase D reaction-induced vesicle rupture. J Membr Biol 2012; 245:691-6. [PMID: 22622287 DOI: 10.1007/s00232-012-9438-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 04/17/2012] [Indexed: 10/28/2022]
Abstract
Spherical phospholipid bilayers, or vesicles, were prepared layer by layer using a double-emulsion technique, which allows the outer layer of the vesicles to be formed with two phospholipids that have different head groups: phosphatidylcholine (PC) and phosphatidylethanolamine. At the outer layer of the vesicles, the phospholipase D (PLD) catalyzed for the conversion of PC to phosphatidic acid. The reaction caused by PLD induced the curvature change of the vesicles, which eventually led to the rupture of the vesicles. Before the investigation, the ratio of dioleoylphosphatidylethanolamine to oleoylhydroxyphosphatidylethanolamine was found as a condition such that the vesicles made with the mixed lipids were as stable as those made with pure dioleoylphosphatidylcholine. Response time from the PLD injection to vesicle rupture was monitored by the composition of the outer layer by the fluorescence intensity change of pH-sensitive dye encapsulated in the vesicles. The response time began to be slowed at approximately 30 % PC. The response times for the compositions were associated with the surface density of PC at the outer layer. These results also seem to be determined by the size of PLD, specifically the PLD active site.
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30
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Wang S, Zhao W, Song J, Cheng S, Fan LJ. A Platform for Preparation of Monodispersed Fluorescent Conjugated Polymer Microspheres with Core-Shell Structures. Macromol Rapid Commun 2012; 34:102-8. [DOI: 10.1002/marc.201200560] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 09/13/2012] [Indexed: 12/23/2022]
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31
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Phase effect of mixed-phospholipid layer on phospholipase D reaction-induced-vesicle rupture. Colloids Surf B Biointerfaces 2012; 97:207-10. [DOI: 10.1016/j.colsurfb.2012.04.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/13/2012] [Accepted: 04/21/2012] [Indexed: 11/18/2022]
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Cardone A, Lopez F, Affortunato F, Busco G, Hofer AM, Mallamaci R, Martinelli C, Colella M, Farinola GM. An aryleneethynylene fluorophore for cell membrane staining. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2808-17. [PMID: 22749749 DOI: 10.1016/j.bbamem.2012.06.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Revised: 06/02/2012] [Accepted: 06/16/2012] [Indexed: 01/25/2023]
Abstract
The use of an amphiphilic aryleneethynylene fluorophore as a plasma membrane marker in fixed and living mammalian cells and liposome model systems is demonstrated. We show here that the optical properties of the novel dye are almost independent on pH, in the range 5.0-8.0. Spectroscopic characterization performed on unilamellar liposomes ascertained that the fluorescence intensity of the aryleneethynylene fluorophore greatly increases after incorporation in lipidic membranes. Experiments performed on different mammalian cells demonstrated that the novel membrane marker exhibits fast staining and a good photostability that make it a suitable tool for live cell imaging. Importantly, the aryleneethynylene fluorophore was also shown to be a fast and reliable blue membrane marker in classical multicolor immunofluorescence experiments. This study adds new important findings to the recent exploitation of the wide class of aryleneethynylene molecules as luminescent markers for biological investigations.
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Affiliation(s)
- Antonio Cardone
- Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici, Bari, Italy
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Liu HW, Ngo AT, Cosa G. Enhancing the Emissive Properties of Poly(p-phenylenevinylene)-Conjugated Polyelectrolyte-Coated SiO2 Nanoparticles. J Am Chem Soc 2012; 134:1648-52. [DOI: 10.1021/ja208437e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Hsiao-Wei Liu
- Department
of Chemistry and Centre for Self-Assembled
Chemical Structures (CSACS/CRMAA), McGill University, 801 Sherbrooke
Street West, Montreal, Quebec H3A 2K6, Canada
| | - An Thien Ngo
- Department
of Chemistry and Centre for Self-Assembled
Chemical Structures (CSACS/CRMAA), McGill University, 801 Sherbrooke
Street West, Montreal, Quebec H3A 2K6, Canada
| | - Gonzalo Cosa
- Department
of Chemistry and Centre for Self-Assembled
Chemical Structures (CSACS/CRMAA), McGill University, 801 Sherbrooke
Street West, Montreal, Quebec H3A 2K6, Canada
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Ng BC, Chan ST, Lin J, Tolbert SH. Using polymer conformation to control architecture in semiconducting polymer/viral capsid assemblies. ACS NANO 2011; 5:7730-8. [PMID: 21942298 PMCID: PMC3215919 DOI: 10.1021/nn202493w] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Cowpea chlorotic mottle virus is a single-stranded RNA plant virus with a diameter of 28 nm. The proteins comprising the capsid of this virus can be purified and reassembled either by themselves to form hollow structures or with polyanions such as double-stranded DNA or single-stranded RNA. Depending on pH and ionic strength, a diverse range of structures and shapes can form. The work presented here focuses on using these proteins to encapsulate a fluorescent polyanionic semiconducting polymer, MPS-PPV (poly-2-methoxy-5-propyloxy sulfonate phenylene vinlyene), in order to obtain optically active virus-like particles. After encapsulation, fluorescence from MPS-PPV shows two distinct peaks, which suggests the polymer may be in two conformations. A combination of TEM, fluorescence anisotropy, and sucrose gradient separation indicate that the blue peak arises from polymer encapsulated into spherical particles, while the redder peak corresponds to polymers contained in rod-like cages. Ionic strength during assembly can be used to tune the propensity to form rods or spheres. The results illustrate the synergy of hybrid synthetic/biological systems: polymer conformation drives the structure of this composite material, which in turn modifies the polymer optical properties. This synergy could be useful for the future development of synthetic/biological hybrid materials with designated functionality.
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Affiliation(s)
- Benny C. Ng
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095-1569, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA 90095-7227, USA
| | - Stephanie T. Chan
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095-1569, USA
| | - Jason Lin
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095-1569, USA
| | - Sarah H. Tolbert
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095-1569, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA 90095-7227, USA
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Effect of Phospholipid Bilayer Phase Asymmetry on Phospholipase D Reaction-Induced Vesicle Rupture. J Membr Biol 2011; 244:55-9. [DOI: 10.1007/s00232-011-9397-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 09/23/2011] [Indexed: 11/26/2022]
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Abstract
The early detection of many human diseases is crucial if they are to be treated successfully. Therefore, the development of imaging techniques that can facilitate early detection of disease is of high importance. Changes in the levels of enzyme expression are known to occur in many diseases, making their accurate detection at low concentrations an area of considerable active research. Activatable fluorescent probes show immense promise in this area. If properly designed they should exhibit no signal until they interact with their target enzyme, reducing the level of background fluorescence and potentially endowing them with greater sensitivity. The mechanisms of fluorescence changes in activatable probes vary. This review aims to survey the field of activatable probes, focusing on their mechanisms of action as well as illustrating some of the in vitro and in vivo settings in which they have been employed.
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Affiliation(s)
- Christopher R Drake
- Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, Box 0946, San Francisco, CA, 94107, USA
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Park JW. Curvature effect on nanometer-scale surface properties of phospholipid layers. Colloids Surf B Biointerfaces 2011; 86:166-8. [PMID: 21531121 DOI: 10.1016/j.colsurfb.2011.03.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 03/27/2011] [Accepted: 03/28/2011] [Indexed: 11/19/2022]
Abstract
Phospholipid bilayers were formed through liposome fusion on surfaces with different curvatures that were defined with silica spheres deposited on silicon water. Prior to the fusion, the surfaces became hydrophobic with octadecyltrimethoxysilane solution. Using atomic force microscope, surface forces were measured on dipalmitoylphosphatidylcholine (DPPC) layers and dioleoylphosphatidylcholine (DOPC) layers upon the curvature at 25°C. The short-range repulsions were higher at 20 and 100 nm curvatures than other curvatures for the DPPC layer, while they were lower for the DOPC layer. Since it was known that the forces are related to its low mechanical stability of the lipid layer, this opposite behavior was analyzed in terms of stability upon the curvature, which appears to be eventually determined by the correlation between the lipid molecule geometry and the surface curvature.
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Affiliation(s)
- Jin-Won Park
- Department of Chemical Engineering, College of Engineering, Seoul National University of Science and Technology, Nowonku, Seoul, 173-743, South Korea.
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Aili D, Mager M, Roche D, Stevens MM. Hybrid nanoparticle-liposome detection of phospholipase activity. NANO LETTERS 2011; 11:1401-1405. [PMID: 20795711 DOI: 10.1021/nl1024062] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A flexible nanoparticle-based phospholipase (PL) assay is demonstrated in which the enzymatic substrate is decoupled from the nanoparticle surface. Liposomes are loaded with a polypeptide that is designed to heteroassociate with a second polypeptide immobilized on gold nanoparticles. Release of this polypeptide from the liposomes, triggered by PL, induces a folding-dependent nanoparticle bridging aggregation. The colorimetric response from this aggregation enables straightforward and continuous detection of PL in the picomolar range. The speed, specificity, and flexibility of this assay make it appropriate for a range of applications, from point of care diagnostics to high-throughput pharmaceutical screening.
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Affiliation(s)
- Daniel Aili
- Department of Materials and Institute of Biomedical Engineering, Imperial College London, SW7 2AZ London, UK
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Li Y, Bai H, Li C, Shi G. Colorimetric assays for acetylcholinesterase activity and inhibitor screening based on the disassembly-assembly of a water-soluble polythiophene derivative. ACS APPLIED MATERIALS & INTERFACES 2011; 3:1306-1310. [PMID: 21438627 DOI: 10.1021/am200101n] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A complex between an anionic polythiophene derivative (PT-COO(-)) and a cationic surfactant, myristoylcholine, has been prepared and applied to be colorimetric probe for acetylcholinesterase (AChE) assays. The complex formation process, AChE activity assay and inhibitor screening has been studied by absorption spectroscopy. It was confirmed that the introduction of myristoylcholine into PT-COO(-) phosphate buffer solution resulted in the disassembly of PT-COO(-) aggregates, and further addition of AChE into the above solution led to the reassembly of PT-COO(-) due to the catalyzed hydrolysis of myristoylcholine and the collapse of the complex. The colorimetric assay for AChE can be readily realized with the concentration of AChE as low as 0.2 U/mL. The results also demonstrate that the colorimetric approach can be applied for screening inhibitors of AChE.
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Affiliation(s)
- Yugang Li
- Department of Chemistry, Tsinghua University, Beijing 100084, China
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Ngo AT, Lau KL, Quesnel JS, Aboukhalil R, Cosa G. Deposition of anionic conjugated poly(phenylenevinylene) onto silica nanoparticles via electrostatic interactions — Assembly and single-particle spectroscopy. CAN J CHEM 2011. [DOI: 10.1139/v10-141] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Fluorescent nanoparticles were prepared via adsorption of the conjugated polyelectrolyte poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene] (MPS-PPV) onto 50 and 100 nm aminosilane functionalized silica beads. The particles were investigated via ensemble and single-molecule or -particle spectroscopy techniques to quantify the effect of the silica bead core on the exciton migration efficiency within the polymer. Ensemble emission spectra and ensemble fluorescence quenching studies with methyl viologen are consistent with good exciton migration along the polymer in the polymer-coated bead. The silica nanobead scaffolding preserves the sensitivity of the free polymer and provides a controllable architecture that minimizes nonspecific interactions. Single-particle spectroscopy studies were conducted on particles immobilized onto the positively charged surface of glass cover slips. Particle immobilization enabled us to monitor the effect of oxygen scavenger solutions on individual particles by changing the surrounding solution. The intensity–time trajectories of individual beads provide a mechanism of signal transduction with potential applications in multiplexing studies. Hundreds of individual beads can be imaged in a rapid parallel fashion.
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Affiliation(s)
- An T. Ngo
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), McGill University, Otto Maass Bldg, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada
| | - Kai L. Lau
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), McGill University, Otto Maass Bldg, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada
| | - Jeffrey S. Quesnel
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), McGill University, Otto Maass Bldg, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada
| | - Robert Aboukhalil
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), McGill University, Otto Maass Bldg, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada
| | - Gonzalo Cosa
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada
- Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), McGill University, Otto Maass Bldg, 801 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada
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Martínez-Máñez R, Sancenón F, Biyikal M, Hecht M, Rurack K. Mimicking tricks from nature with sensory organic–inorganic hybrid materials. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm11210d] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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42
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Tkachov R, Senkovskyy V, Oertel U, Synytska A, Horecha M, Kiriy A. Microparticle-Supported Conjugated Polyelectrolyte Brushes Prepared by Surface-Initiated Kumada Catalyst Transfer Polycondensation for Sensor Applications. Macromol Rapid Commun 2010; 31:2146-50. [DOI: 10.1002/marc.201000411] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 08/17/2010] [Indexed: 11/11/2022]
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43
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Wang Y, Zhang Y, Liu B. Conjugated Polyelectrolyte Based Fluorescence Turn-On Assay for Real-Time Monitoring of Protease Activity. Anal Chem 2010; 82:8604-10. [DOI: 10.1021/ac101695x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Yanyan Wang
- Department of Chemical and Biomolecular Engineering, 4 Engineering Drive 4, National University of Singapore, Singapore 117576, Singapore
| | - Yong Zhang
- Department of Chemical and Biomolecular Engineering, 4 Engineering Drive 4, National University of Singapore, Singapore 117576, Singapore
| | - Bin Liu
- Department of Chemical and Biomolecular Engineering, 4 Engineering Drive 4, National University of Singapore, Singapore 117576, Singapore
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44
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Feng F, Liu L, Yang Q, Wang S. Water-Soluble Conjugated Polymers for Fluorescent-Enzyme Assays. Macromol Rapid Commun 2010; 31:1405-21. [DOI: 10.1002/marc.201000020] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 02/25/2010] [Indexed: 11/08/2022]
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45
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Ngo AT, Cosa G. Assembly of zwitterionic phospholipid/conjugated polyelectrolyte complexes: structure and photophysical properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:6746-6754. [PMID: 20017509 DOI: 10.1021/la904100q] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report on the formation of complexes between zwitterionic phospholipid vesicles and an anionic fluorescent conjugated polyelectrolyte and the effect of mono- and divalent cations on the photophysical properties of these complexes. Our goal is to gain an understanding of the interplay of morphology and exciton transport in these complexes, information that is critical to designing efficient lipid/conjugated polymer-based sensors. Our studies further underscore the potential application of lipid/conjugated polymer complexes in light-harvesting devices. Our work focuses on the negatively charged conjugated polyelectrolyte poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene] (MPS-PPV) and its interaction with the zwitterionic lipid dioleoylphosphatidylcholine (DOPC). We utilize monovalent and divalent cations as a tool to control and explore the interaction of MPS-PPV with lipids. We show that Ca(2+) ions promote the complexation of zwitterionic lipids and MPS-PPV in comparison to Na(+) ions. The addition of increasing amounts of zwitterionic phospholipids in the form of vesicles gradually disrupts MPS-PPV aggregates albeit vesicle structure is preserved in Na(+) buffer. Lipid complexation and the resulting MPS-PPV aggregate disruption produces an intensity enhancement and blue shifting of the MPS-PPV emission peak. In the absence of Ca(2+), the intensity enhancement and blue shift reach a plateau at larger than a 10:1 lipid/MPS-PPV monomer mole ratio. In the presence of Ca(2+), a plateau is reached at equimolar concentrations of MPS-PPV and lipid. Vesicle particle coalescence and agglomerate formation are observed herein. Lipid complexation and concomitant MPS-PPV shielding is shown to diminish the quenching of MPS-PPV emission by water-soluble quencher methyl viologen. FRET experiments conducted with membrane-intercalating acceptor dye DiD further underscore the large lipid/polymer interaction mediated by Ca(2+). We observe efficient light harvesting and MPS-PPV-amplified emission quenching in Ca(2+) buffer and to a lesser extent in Na(+) buffer. Our results highlight how the interplay of a zwitterionic lipid, cations, and buffer, in combination with the conjugated polyelectrolyte MPS-PPV, provides rich diversity in architecture and photophysical properties.
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Affiliation(s)
- An Thien Ngo
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC, H3A 2K6, Canada
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46
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Ding L, Chi EY, Schanze KS, Lopez GP, Whitten DG. Insight into the mechanism of antimicrobial conjugated polyelectrolytes: lipid headgroup charge and membrane fluidity effects. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:5544-5550. [PMID: 20000327 DOI: 10.1021/la9038045] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The interactions of antimicrobial cationic conjugated polyelectrolytes (CPEs) with two model membranes, liposomes and lipid monolayers at the air-water interface, have been investigated by fluorescence emission, fluorescence quenching, pressure-area isotherm, and dynamic light scattering measurements. This study continues the evaluation of the antimicrobial mechanism of a cationic poly(phenylene ethynylene) (PPE)-based CPE (polymer 1), which contains a 2,5-thienylene moiety in the repeat unit. To this end, the interactions of polymer 1 with lipids with varying headgroup charge and acyl chain length have been examined. Our results show that the cationic polymer 1 can efficiently associate with and insert into anionic phosphatidylglycerol (PG) membranes. However, polymer 1 does not exhibit any interactions with zwitterionic lipid membranes composed of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) lipids. Polymer 1's selective affinity toward anionic lipids over zwitterionic lipids makes it an attractive antimicrobial agent with low toxicity. The interactions of polymer 1 with lipid membranes of different fluidity were studied by varying the surface pressure of lipid monolayers and by adjusting the temperature of liposomes. We observe that increasing membrane fluidity enhances both the conformational changes of polymer 1 upon associating with lipid membranes and the extent of polymer 1 insertion into lipid monolayers. We also find that the thickness of the lipid bilayers, modulated by acyl chain length, affects the extent of polymer 1 incorporation into the lipid bilayer.
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Affiliation(s)
- Liping Ding
- Center for Biomedical Engineering, Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131-1341, USA
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47
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Chemburu S, Fenton K, Lopez GP, Zeineldin R. Biomimetic silica microspheres in biosensing. Molecules 2010; 15:1932-57. [PMID: 20336023 PMCID: PMC6257317 DOI: 10.3390/molecules15031932] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 03/16/2010] [Accepted: 03/17/2010] [Indexed: 11/16/2022] Open
Abstract
Lipid vesicles spontaneously fuse and assemble into a lipid bilayer on planar or spherical silica surfaces and other substrates. The supported lipid bilayers (SLBs) maintain characteristics of biological membranes, and are thus considered to be biomembrane mimetic systems that are stable because of the underlying substrate. Examples of their shared characteristics with biomembranes include lateral fluidity, barrier formation to ions and molecules, and their ability to incorporate membrane proteins into them. Biomimetic silica microspheres consisting of SLBs on solid or porous silica microspheres have been utilized for different biosensing applications. The advantages of such biomimetic microspheres for biosensing include their increased surface area to volume ratio which improves the detection limits of analytes, and their amenability for miniaturization, multiplexing and high throughput screening. This review presents examples and formats of using such biomimetic solid or porous silica microspheres in biosensing.
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Affiliation(s)
- Sireesha Chemburu
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, NM 87131, USA
| | - Kyle Fenton
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, NM 87131, USA
| | - Gabriel P. Lopez
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, NM 87131, USA
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
- Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC 27708, USA
| | - Reema Zeineldin
- Department of Pharmaceutical Sciences, Massachusetts College of Pharmacy and Health Sciences, 19 Foster Street, Worcester, MA 01608, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-508-373-5762; Fax: +1- 508-890-5618
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48
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Ding L, Chi EY, Chemburu S, Ji E, Schanze KS, Lopez GP, Whitten DG. Insight into the mechanism of antimicrobial poly(phenylene ethynylene) polyelectrolytes: interactions with phosphatidylglycerol lipid membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:13742-51. [PMID: 20560549 DOI: 10.1021/la901457t] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The interactions of antimicrobial poly(phenylene ethynylene) (PPE)-based cationic conjugated polyelectrolytes (CPEs) with lipid membranes were investigated to gain insight into the mechanism of their biocidal activity. Three model membrane systems comprising negatively charged phosphatidylglycerol (PG) lipids were used to mimic the bacterial cell membrane, including unilamellar lipid vesicles in aqueous solution, lipid bilayer coated silica microspheres, and lipid monolayers at the air-water interface. Two PPE CPEs, one containing a thiophene moiety on the PPE repeat unit and the second containing a diazabicyclooctane (DABCO) moiety on the pendant side chain, were chosen, since the former exhibits distinct dark biocidal activity and the latter shows strong light-activated antimicrobial activity but little dark biocidal activity. The interactions of these two PPE polymers with lipid membranes were characterized in detail by CPE fluorescence spectral changes, fluorescence resonance energy transfer (FRET), fluorescence quenching, monolayer insertion, and dynamic light scattering assays. Both PPE polymers exhibit affinity for the anionic lipid membrane systems. Their concomitant association and insertion into the membrane leads to conformational changes of the PPE polymer from an aggregated state to a more extended state, as evidenced by the polymer's enhanced fluorescence and FRET between the polymer and rhodamine incorporated in the lipid membrane. In comparison, the thiophene polymer exhibits stronger interactions with PG lipid membranes than the DABCO-containing polymer. The former induces a larger fluorescence enhancement, shows faster transfer across the lipid membrane, and inserts more readily and to a higher extent into lipid monolayers. The observed differences between the two PPE polymers in their interactions with the lipid membrane may stem from their structural differences, as the DABCO-containing polymer has a much bulkier and larger pendant group on its side chain. The higher degree of membrane interaction and insertion, and subsequent membrane disorganization, of the thiophene polymer may account for its dark biocidal activity.
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Affiliation(s)
- Liping Ding
- Center for Biomedical Engineering, Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131-0001, USA
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49
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Liu Y, Ogawa K, Schanze KS. Conjugated polyelectrolytes as fluorescent sensors. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2009. [DOI: 10.1016/j.jphotochemrev.2009.10.003] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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50
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An L, Wang S. Conjugated Polyelectrolytes as New Platforms for Drug Screening. Chem Asian J 2009; 4:1196-206. [DOI: 10.1002/asia.200900148] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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