Functionalized Thermosensitive Latex Particles: Useful Tools for Diagnostics

Pichot, Christian; Taniguchi, Tadatsugu; Delair, Th.; Elaı̈ssari, Abdelhamid

doi:10.1081/dis-120021799

Cited by 30 publications

(37 citation statements)

References 23 publications

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“…1 Novel functional microspheres include thermosensitive microspheres for drug delivery systems [2][3][4][5][6] and radiopaque microspheres as contrast agents for X-ray imaging. 7 Typically, polymeric microspheres are synthesized directly by heterogenous polymerization techniques (e.g., emulsion and dispersion polymerization) or are prepared by modification of existing particles.…”

Section: Introductionmentioning

confidence: 99%

Ambient temperature synthesis of well‐defined microspheres via precipitation polymerization initiated by UV‐irradiation

Joso

Pan

Stenzel

et al. 2007

J. Polym. Sci. A Polym. Chem.

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Section: Introductionmentioning

confidence: 99%

Ambient temperature synthesis of well‐defined microspheres via precipitation polymerization initiated by UV‐irradiation

Joso

Pan

Stenzel

et al. 2007

J. Polym. Sci. A Polym. Chem.

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“…32 For temperatures far away from the T VPT the dT 25 -ROX lifetimes decrease with temperature in a similar way as that observed in solution. Figure 2 shows the steady-state anisotropy (r ss ) of dT 25 -ROX in phosphate buffer solution and when adsorbed on the shell of the latex particles at several temperatures. In solution, r ss decreases from 0.10 ( 0.02 at 15°C to 0.04 ( 0.02 at 50°C.…”

Section: Resultsmentioning

confidence: 99%

“…This seems to be the main cause for their high quantum yields (∼1) and monoexponential decays, 40-42 which are, in addition, almost temperature independent. [43][44][45][46] The fluorescence quantum yield of dT 25 -ROX in water is 0.90 ( 0.05, slightly lower than 1.0, due to water quenching which seems to involve energy dissipation through the hydrogen bonds with the rhodamine. 32 In phosphate buffer solution (pH 5.5), the fluorescence decays of dilute solutions (∼10 -8 M) are monoexponential with lifetimes slightly changing from 4.9 ns at room temperature (22°C) to 4.8 ns at 45°C.…”

Section: Resultsmentioning

confidence: 99%

“…The concentration of oligonucleotide was adjusted, knowing the adsorption isotherms at 22°C, to satisfy the condition that more than 95% of the ODNs are adsorbed. 32 The concentration of dT 25 -ROX in solution is always less than 5.0 × 10 -10 M. Before the measurements, the samples were incubated at room temperature (23°C) for at least 3 h in order to guarantee the adsorption equilibrium. 27 Fluorescence Spectra and Anisotropy.…”

Section: Methodsmentioning

confidence: 99%

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Dynamics of Oligonucleotides Adsorbed on Thermosensitive Core−Shell Latex Particles

Prazeres¹,

Fedorov²,

Martinho³

2004

J. Phys. Chem. B

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The dynamics of a rhodamine X-labeled oligonucleotide composed of 25 mers of thymine (dT 25 -ROX) in solution or adsorbed on the thermosensitive shell of poly(methyl methacrylate/N-isopropylacrylamide), poly-(MMA/NIPAM), core-shell nanoparticles, with a characteristic volume phase transition temperature (T VPT ) at ∼32°C, were studied as a function of temperature by fluorescence anisotropy. The time-resolved anisotropy decay of the dT 25 -ROX oligonucleotides in buffered solution (pH 5.5) is biexponential. The results are interpreted in terms of the "two-step" model, where the fast correlation time (θ w ) is attributed to the restricted "wobbling" motion of the bound ROX to the oligonucleotide (ODN) strand in a cone, while the slow correlation time (θ oligo ) is related to the rotation of the oligonucleotide as a whole. Both correlation times decrease with temperature due to the variation of the viscosity of the medium. The anisotropy decays of dT 25 -ROX adsorbed on the PNIPAM thermosensitive shell were interpreted in terms of two models: the "wobbling-in-two-cones" and the heterogeneous population model. In both models, the fast correlation time is due to the "wobbling" motion of ROX (θ w ). The half-angle of the cone of the ROX "wobbling" motion (φ) decreases from ∼34°b elow the VPT to ∼11°above it, due to the increasing constraints imposed by the PNIPAM chains. The slow correlation time describes the overall rotational motion of the ODNs (θ oligo ) without restrictions (heterogeneous population model) or restricted to the "wobbling" in a cone ("wobbling-in-two-cones" model). The θ oligo values of the adsorbed ODNs are higher than in solution and increase with temperature from ∼2.6 ns at 15°C to reach a constant value of ∼6.6 ns after the transition due to the increasing friction by the PNIPAM chains. The anisotropy decay shows a residual component at long times (r ∞ ) that increases with temperature along the VPT, which is essentially due to the increasing percentage of immobilized ODNs from ∼14% at 15°C to ∼70% above the transition (heterogeneous population model) or to the increase of the order parameter, S oligo , with temperature from 0.38 (φ oligo ∼ 60°) at 15°C to 0.85 (φ oligo ∼ 27°) at 45°C ("wobbling-in-twocones" model). Both models show that the whole motion of the ODNs and the randomization of their orientations are strongly restricted along the volume phase transition of the PNIPAM shell.

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“…However, it is necessary to incorporate reactive centers in the microgel for the coupling of bioactive molecules. Primary amines are particularly useful sites for coupling [6], and Pichot and co-workers have described the preparation of amino-containing microgels [7], which are suitable for coupling nucleic acid probes for virus detection [8,9]. In their work, primary amino groups were introduced by copolymerization of aminoethylmethacrylate, a charged monomer in aqueous solution.…”

Section: Introductionmentioning

confidence: 99%

A new route to poly(N-isopropylacrylamide) microgels supporting a polyvinylamine corona

Pelton

2004

Journal of Colloid and Interface Science

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Functionalized Thermosensitive Latex Particles: Useful Tools for Diagnostics

Cited by 30 publications

References 23 publications

Ambient temperature synthesis of well‐defined microspheres via precipitation polymerization initiated by UV‐irradiation

Ambient temperature synthesis of well‐defined microspheres via precipitation polymerization initiated by UV‐irradiation

Dynamics of Oligonucleotides Adsorbed on Thermosensitive Core−Shell Latex Particles

A new route to poly(N-isopropylacrylamide) microgels supporting a polyvinylamine corona

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