Location of Fluorotryptophan Sequestered in an Amphiphilic Nanoparticle by Rotational-Echo Double-Resonance NMR

Baugher, A. H.; Goetz, Jon M.; McDowell, Lynda M.; Huang, Haiyong; Wooley, Karen L.; Schaefer, Jacob

doi:10.1016/s0006-3495(98)77702-1

Cited by 25 publications

(22 citation statements)

References 12 publications

(14 reference statements)

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“…Due to the regioselective crosslinks in the peripheral shell region, these nanoscale assemblies can be diluted without disassembly, and have increased dimensional stability compared to their non-crosslinked micellar counterparts [1, 40–42]. The core of the SCKs can retain its host capabilities, because the lack of crosslinks in the core region maintains chain mobility and access to the core volume, for sequestering of guests [43–45]. Moreover, just as in the case of macroscopic crosslinked networks originating from linear polymers [46], the readily adjustable shell crosslinking density allows for gating of the transport of those guests into and out of the core domain, while retaining the structural integrity of the SCK nanostructures [47].…”

Section: Introductionmentioning

confidence: 99%

Tuning core vs. shell dimensions to adjust the performance of nanoscopic containers for the loading and release of doxorubicin

Lin

Lee

Zhu

et al. 2011

Journal of Controlled Release

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Detailed studies were performed to probe the effects of the core and shell dimensions of amphiphilic, shell crosslinked, knedel-like polymer nanoparticles (SCKs) on the loading and release of doxorubicin (DOX), a widely-used chemotherapy agent, in aqueous buffer, as a function of the solution pH. Effects of the nanoparticle composition were held constant, by employing SCKs constructed from a single type of amphiphilic diblock copolymer, poly(acrylic acid)-b-polystyrene (PAA-b-PS). A series of four SCK nanoparticle samples, ranging in number-average hydrodynamic diameter from 14–30 nm, was prepared from four block copolymers having different relative block lengths and absolute degrees of polymerization. The ratios of acrylic acid to styrene block lengths ranged from 0.65 to 3.0, giving SCKs with ratios of shell to core volumes ranging from 0.44 to 2.1. Although the shell thicknesses were calculated to be similar (1.5–3.1 nm by transmission electron microscopy (TEM) calculations and 3.5–4.9 nm by small angle neutron scattering (SANS) analyses), two of the SCK nanoparticles had relatively large core diameters (19 ± 2 and 20 ± 2 nm by TEM; 17.4 and 15.3 nm by SANS), while two had similar, smaller core diameters (11 ± 2 and 13 ± 2 nm by TEM; 9.0 and 8.9 nm by SANS). The SCKs were capable of being loaded with 1500–9700 DOX molecules per each particle, with larger numbers of DOX molecules packaged within the larger core SCKs. Their shell-to-core volume ratio showed impact on the rates and extents of release of DOX, with the volume occupied by the poly(acrylic acid) shell relative to the volume occupied by the polystyrene core correlating inversely with the diffusion-based release of DOX. Given that the same amount of polymer was used to construct each SCK sample, SCKs having smaller cores and higher acrylic acid vs. styrene volume ratios were present at higher concentrations than were the larger core SCKs, and gave lower final extents of release., Higher final extents of release and faster rates of release were observed for all DOX-loaded particle samples at pH 5.0 vs. pH 7.4, respectively, ca. 60% vs. 40% at 60 h, suggesting promise for enhanced delivery within tumors and cells. By fitting the data to the Higuchi model, quantitative determination of the kinetics of release was made, giving rate constants ranging from 0.0431 to 0.0540 h−½ at pH 7.4 and 0.106 to 0.136 h−½ at pH 5.0. In comparison, the non-crosslinked polymer micelle analogs exhibited rate constants for release of DOX of 0.245 and 0.278 h−½ at pH 7.4 and 5.0, respectively. These studies point to future directions to craft sophisticated devices for controlled drug release.

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Section: Introductionmentioning

confidence: 99%

Tuning core vs. shell dimensions to adjust the performance of nanoscopic containers for the loading and release of doxorubicin

Lin

Lee

Zhu

et al. 2011

Journal of Controlled Release

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“…To date, shell-crosslinked, 23,24 core-crosslinked 25 and interface-crosslinked 26 micelles had been developed as stabilized nanocarriers for drug delivery. Among them, shell-crosslinked micelles take more advantages due to: (1) their relatively large and exible hydrophobic core which enhanced drug loading efficiency; [27][28][29] (2) the crosslinked hydrophilic shell could be controlled by stimuli-responsive crosslinkers. 30,31 e.g.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of crosslinkable diblock terpolymers PDPA-b-P(NMS-co-OEG) and preparation of shell-crosslinked pH/redox-dual responsive micelles as smart nanomaterials

et al. 2019

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“…Alternately, it may be possible to design an inclusion complex with another fluorinated small-molecule guest, which has restricted motion, for testing REDOR performance at many rotor cycles in the face of large CSAs. Validating the accuracy of long-distance REDOR measurements is critical to applications which to date have included determining the structure of polymeric nanoparticles loaded with small molecules,[14] an important cancer drug bound to tubulin, [1] and receptor-receptor distances in bacterial signaling complexes[15]; the work presented here paves the way for even more applications in the future.…”

Section: Resultsmentioning

confidence: 99%

Design and characterization of a calixarene inclusion compound for calibration of long-range carbon–fluorine distance measurements by solid-state NMR

Fowler

Khalifah

Thompson

2010

Journal of Magnetic Resonance

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An inexpensive, easily synthesized calixarene:fluorotoluene host:guest inclusion complex has been designed for optimization and calibration of solid-state NMR measurements of carbon-fluorine distances using Rotational Echo DOuble Resonance (REDOR). Complexation of the fluorotoluene with the calixarene host separates the molecules such that simple two-spin behavior is observed for one site with a 4.08 Å carbon-fluorine distance. Fluorotoluene dynamics within the calixarene matrix causes motional averaging of the dipolar couplings that make it possible to easily optimize REDOR experiments and test their accuracy for relatively long distance measurements (> 6.6 Å). This provides a new tool for accurate REDOR measurements of long carbon-fluorine distances, which have important applications in the characterization of fluorine-containing drugs, proteins, and polymers.

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Location of Fluorotryptophan Sequestered in an Amphiphilic Nanoparticle by Rotational-Echo Double-Resonance NMR

Cited by 25 publications

References 12 publications

Tuning core vs. shell dimensions to adjust the performance of nanoscopic containers for the loading and release of doxorubicin

Tuning core vs. shell dimensions to adjust the performance of nanoscopic containers for the loading and release of doxorubicin

Synthesis of crosslinkable diblock terpolymers PDPA-b-P(NMS-co-OEG) and preparation of shell-crosslinked pH/redox-dual responsive micelles as smart nanomaterials

Design and characterization of a calixarene inclusion compound for calibration of long-range carbon–fluorine distance measurements by solid-state NMR

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