High-frequency dielectric study of side-chain dynamics in poly(lysine) aqueous solutions

Bordi, F.; Cametti, C.; Paradossi, Gaio

doi:10.1002/(sici)1097-0282(200002)53:2<129::aid-bip2>3.0.co;2-y

Cited by 16 publications

(13 citation statements)

References 13 publications

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“…The comparison of the hydration levels h ϭ 11 and 17% shows only an insignificant decrease of the correlation time of motion. Moreover, the comparison with the solution data 16,17 indicates that the side chain motion remains in the nanosecond range. Thus, one may conclude that the most dramatic changes of the internal dynamics upon hydration occur between 0 and 11%.…”

Section: Side Chain Dynamicsmentioning

confidence: 88%

Hydration dependence of backbone and side chain polylysine dynamics: A ¹³C solid‐state NMR and IR spectroscopy study

Krushelnitsky

Faizullin

Reichert³

2003

Biopolymers

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Section: Side Chain Dynamicsmentioning

confidence: 88%

Hydration dependence of backbone and side chain polylysine dynamics: A ¹³C solid‐state NMR and IR spectroscopy study

Krushelnitsky

Faizullin

Reichert³

2003

Biopolymers

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“…This result suggests that the grafted long side-chain PEO is inclined to forming complex with main-chain PAA, not like the charged short side-chain which can fluctuate or polarize in the field. 12,13 In conclusion, we thought that the low-frequency relaxation originates from the interface polarization effect between the complex and aqueous solution.…”

Section: Articlementioning

confidence: 94%

“…For example, the existence of a dielectric dispersion in aqueous solutions of poly(L-glutamic acid) in a region around 100 MHz, attributable to internal motions of the polar groups of the side chains, has been reported by Mashimo et al 10 and this was later confirmed by Bordi et al 11 Moreover, the microdynamics of the side chains of poly(lysine) and chitosan derivatives were also reported. 12,13 The above studies showed that DRS is useful for exploring microdynamic information of the charged short side chain in polyelectrolyte solution. But the polyelectrolyte with long and uncharged side chain has not been investigated by DRS; this may be blamed on lack of a suitable model to describe side-chain motion in solution.…”

Section: Introductionmentioning

confidence: 99%

Effects of Concentration and Temperature on the Dynamic Behavior of PAA-g-PEO Aqueous Solutions with Different Counterion Species: A Dielectric Spectroscopy Study

Liu

Zhao

2012

J. Phys. Chem. B

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Dielectric properties of PAA-g-PEO-7% solutions with different counterions were measured as a function of concentration and temperature over a frequency range of 40 Hz to 110 MHz. After the contribution of electrode polarization effects was subtracted, the dielectric spectra of PAA-g-PEO-7% solutions showed three relaxation processes in the experimental frequency range, named low-, mid-, and high-frequency relaxation. The observed three relaxations were strictly analyzed by using the Cole-Cole relaxation function, and the dielectric parameters (dielectric increment Δε and the relaxation time τ) were obtained. The scaling relation of dielectric increment and relaxation time of high frequency with concentration C(p) were obtained and compared with the predictions of scaling theories. The information on the dynamics and microstructure of PAA-g-PEO-7% was obtained. Using different counterion species, the mid- and high-frequency relaxation mechanisms were attributed to the fluctuation of condensed counterions and free counterions, respectively, and the low-frequency relaxation was considered to be caused by the interface polarization of a complex formed by the hydrogen bonding between carboxylic group of PAA and ether oxygen on the side-chain PEO. In addition, by means of Eyring equation, the thermodynamic parameters, enthalpy change ΔH and entropy change ΔS, of the three relaxations were calculated from the relaxation time and discussed from the microscopic thermodynamical view.

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“…A detailed description about cell cultures and radiowave spectroscopy measurements may be found elsewhere (27,34). Briefly, C6 glioma cells were grown in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum and 50 mg/ mL of gentamicin at 37 C under an atmosphere of 5% CO 2 in air.…”

Section: Methodsmentioning

confidence: 99%

L-DOPA Preloading Increases the Uptake of Borophenylalanine in C6 Glioma Rat Model: A New Strategy to Improve BNCT Efficacy

Capuani

Gili

Bozzali

et al. 2008

International Journal of Radiation Oncology*Biology*Physics

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Purpose: Boron neutron capture therapy (BNCT) is a radiotherapeutic modality based on 10 B(n,a) 7 Li reaction, for the treatment of malignant gliomas. One of the main limitations for BNCT effectiveness is the insufficient intake of 10 B nuclei in the tumor cells. This work was aimed at investigating the use of L-DOPA as a putative enhancer for 10 B-drug 4-dihydroxy-borylphenylalanine (BPA) uptake in the C6-glioma model. The investigation was first performed in vitro and then extended to the animal model. Methods and Materials: BPA accumulation in C6-glioma cells was assessed using radiowave dielectric spectroscopy, with and without L-DOPA preloading. Two L-DOPA incubation times (2 and 4 hours) were investigated, and the corresponding effects on BPA accumulation were quantified. C6-glioma cells were also implanted in the brain of 32 rats, and tumor growth was monitored by magnetic resonance imaging. Rats were assigned to two experimental branches: (1) BPA administration; (2) BPA administration after pretreatment with L-DOPA. All animals were sacrificed, and assessments of BPA concentrations in tumor tissue, normal brain, and blood samples were performed using high-performance liquid chromatography. Results: L-DOPA preloading induced a massive increase of BPA concentration in C6-glioma cells only after a 4-hour incubation. In the animal model, L-DOPA pretreatment produced a significantly higher accumulation of BPA in tumor tissue but not in normal brain and blood samples. Conclusions: This study suggests the potential use of L-DOPA as enhancer for BPA accumulation in malignant gliomas eligible for BNCT. L-DOPA preloading effect is discussed in terms of membrane transport mechanisms. Ó

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High-frequency dielectric study of side-chain dynamics in poly(lysine) aqueous solutions

Cited by 16 publications

References 13 publications

Hydration dependence of backbone and side chain polylysine dynamics: A ¹³C solid‐state NMR and IR spectroscopy study

Hydration dependence of backbone and side chain polylysine dynamics: A ¹³C solid‐state NMR and IR spectroscopy study

Effects of Concentration and Temperature on the Dynamic Behavior of PAA-g-PEO Aqueous Solutions with Different Counterion Species: A Dielectric Spectroscopy Study

L-DOPA Preloading Increases the Uptake of Borophenylalanine in C6 Glioma Rat Model: A New Strategy to Improve BNCT Efficacy

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High-frequency dielectric study of side-chain dynamics in poly(lysine) aqueous solutions

Cited by 16 publications

References 13 publications

Hydration dependence of backbone and side chain polylysine dynamics: A 13C solid‐state NMR and IR spectroscopy study

Hydration dependence of backbone and side chain polylysine dynamics: A 13C solid‐state NMR and IR spectroscopy study

Effects of Concentration and Temperature on the Dynamic Behavior of PAA-g-PEO Aqueous Solutions with Different Counterion Species: A Dielectric Spectroscopy Study

L-DOPA Preloading Increases the Uptake of Borophenylalanine in C6 Glioma Rat Model: A New Strategy to Improve BNCT Efficacy

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Hydration dependence of backbone and side chain polylysine dynamics: A ¹³C solid‐state NMR and IR spectroscopy study

Hydration dependence of backbone and side chain polylysine dynamics: A ¹³C solid‐state NMR and IR spectroscopy study