Diffusion NMR studies of macromolecular complex formation, crowding and confinement in soft materials

Barhoum, Suliman; Palit, Swomitra; Yethiraj, Anand

doi:10.1016/j.pnmrs.2016.01.004

Cited by 29 publications

(28 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…49,50 Since the translational diffusion coefficients (D) of molecular species reflect their effective sizes and shapes, DOSY NMR allows both the identification and separation of the chemical entities in multicomponent systems, and provides information on their intermolecular interactions as well as on the dynamics of the system. 49,51,52 In other words, a small molecule diffuses faster than a large one and the binding of a freely diffusing molecule to another species leads to a decrease of D. Indeed, in the fast exchange limit, the observed diffusion coefficient of the guest is the mole fraction weighted average of the diffusion coefficient of the free and bound states. This means that, in the presence of a complex, the diffusion of the encapsulated molecule will be slower than that measured for the free compound.…”

Section: Sementioning

confidence: 99%

Do Cyclodextrins Encapsulate Volatiles in Deep Eutectic Systems?

Pietro

Dugoni

Ferro

et al. 2019

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

Efficient renewable and non-toxic absorbents can now be designed to eliminate air pollutants such as volatile organic compounds (VOCs) from confined atmospheres. New hybrid materials result from the combination of Deep Eutectic Systems (DES) with well-known VOCs capture agents like β-cyclodextrin (βCD). Yet, a question arises: does βCD retain its encapsulation ability in DES? Multiple NMR techniques are used here to demonstrate the formation of inclusion complexes of βCD with two VOCs, aniline and toluene, in the pure DES reline and in reline/water mixtures. Complexation-induced chemical shift changes and intermolecular hostguest NOEs in the rotating frame give evidence of a genuine encapsulation in the βCD cavity, and complementary information on the dynamics of the VOC is gathered via relaxation and diffusion experiments. This work shows how different NMR techniques can contribute to the design of task-specific sustainable materials for absorption/extraction processes.

show abstract

Section: Sementioning

confidence: 99%

Do Cyclodextrins Encapsulate Volatiles in Deep Eutectic Systems?

Pietro

Dugoni

Ferro

et al. 2019

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

show abstract

“…The details of the PFG NMR method were reviewed recently [31] and are summarized in the Supplemental Material [26]. The dashed blue line in Fig.…”

mentioning

confidence: 99%

Combining Diffusion NMR and Small-Angle Neutron Scattering Enables Precise Measurements of Polymer Chain Compression in a Crowded Environment

Palit

Hamilton

et al. 2017

Phys. Rev. Lett.

Self Cite

View full text Add to dashboard Cite

The effect of particles on the behavior of polymers in solution is important in a number of important phenomena such as the effect of "crowding" proteins in cells, colloid-polymer mixtures, and nanoparticle "fillers" in polymer solutions and melts. In this Letter, we study the effect of spherical inert nanoparticles (which we refer to as "crowders") on the diffusion coefficient and radius of gyration of polymers in solution using pulsed-field-gradient NMR and small-angle neutron scattering (SANS), respectively. The diffusion coefficients exhibit a plateau below a characteristic polymer concentration, which we identify as the overlap threshold concentration c ⋆ . Above c ⋆ , in a crossover region between the dilute and semidilute regimes, the (long-time) self-diffusion coefficients are found, universally, to decrease exponentially with polymer concentration at all crowder packing fractions, consistent with a structural basis for the long-time dynamics. The radius of gyration obtained from SANS in the crossover regime changes linearly with an increase in polymer concentration, and must be extrapolated to c ⋆ in order to obtain the radius of gyration of an individual polymer chain. When the polymer radius of gyration and crowder size are comparable, the polymer size is very weakly affected by the presence of crowders, consistent with recent computer simulations. There is significant chain compression, however, when the crowder size is much smaller than the polymer radius gyration.

show abstract

“…The procedure for analysis of the results is described elsewhere in detail. 26 In Fig. 1, the attenuation in PEG signal intensities were observed as a function of k [=(γδg) 2 (∆ − δ/3)].…”

Section: A Pfg Nmrmentioning

confidence: 99%

“…The spectral sensitivity of PFG NMR allows one to obtain dynamics of multiple species in complex systems simultaneously. [23][24][25][26] Using this spectral selectivity, we measure the self-diffusion coefficient (of both polymer and crowder) as a function of polymer concentration (c p ) and crowder packing fraction (Φ F ). For a polymer diffusing in a colloidal suspension, one may write a modified Stokes-Einstein equation,…”

Section: Introductionmentioning

confidence: 99%

The effect of crowder charge in a model polymer–colloid system for macromolecular crowding: Polymer structure and dynamics

Palit

Hamilton

et al. 2017

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

We have examined the effect of crowder particle charge on macromolecular structure, studied via small-angle neutron scattering, and translational dynamics, studied via pulsed-field gradient NMR, in addition to bulk viscosity measurements, in a polymer macromolecule (polyethylene glycol)-nanoparticle crowder (polysucrose, Ficoll70) model system, in the case where polymer size and crowder size are comparable. While there are modest effects of crowder charge on polymer dynamics at relatively low packing fractions, there is only a tiny effect at the high packing fractions that represent the limit of molecular crowding. We find, via different measures of macromolecular mobility, that the mobility of the flexible polymer in the crowding limit is 10-100 times larger than that of the compact, spherical crowder in spite of their similar size, implying that the flexible polymer chain is able to squeeze through crowder interstices.

show abstract

Diffusion NMR studies of macromolecular complex formation, crowding and confinement in soft materials

Cited by 29 publications

References 55 publications

Do Cyclodextrins Encapsulate Volatiles in Deep Eutectic Systems?

Do Cyclodextrins Encapsulate Volatiles in Deep Eutectic Systems?

Combining Diffusion NMR and Small-Angle Neutron Scattering Enables Precise Measurements of Polymer Chain Compression in a Crowded Environment

The effect of crowder charge in a model polymer–colloid system for macromolecular crowding: Polymer structure and dynamics

Contact Info

Product

Resources

About