Sol−Gel Transition in Nonlinear Hydrogen Bonding Solutions

Wang, Haijun; Hong, Xiao-Zhong; Ba, Xinwu

doi:10.1021/ma0702804

Cited by 5 publications

(2 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Physically cross‐linked hydrogels possess physical junction domains associated with chain entanglements, ionic or hydrogen bonding, and hydrophobic interactions . The interest in these physical hydrogels is obvious since they are easily obtainable in a one‐step process while avoiding the use of cross‐linking agents.…”

Section: Hydrogels For Cell Microencapsulationmentioning

confidence: 99%

Contribution of polymeric materials to progress in xenotransplantation of microencapsulated cells: a review

Mahou

Passemard

Carvello

et al. 2016

Xenotransplantation

View full text Add to dashboard Cite

Cell microencapsulation and subsequent transplantation of the microencapsulated cells require multidisciplinary approaches. Physical, chemical, biological, engineering, and medical expertise has to be combined. Several natural and synthetic polymeric materials and different technologies have been reported for the preparation of hydrogels, which are suitable to protect cells by microencapsulation. However, owing to the frequent lack of adequate characterization of the hydrogels and their components as well as incomplete description of the technology, many results of in vitro and in vivo studies appear contradictory or cannot reliably be reproduced. This review addresses the state of the art in cell microencapsulation with special focus on microencapsulated cells intended for xenotransplantation cell therapies. The choice of materials, the design and fabrication of the microspheres, as well as the conditions to be met during the cell microencapsulation process, are summarized and discussed prior to presenting research results of in vitro and in vivo studies. Overall, this review will serve to sensitize medically educated specialists for materials and technological aspects of cell microencapsulation.

show abstract

Section: Hydrogels For Cell Microencapsulationmentioning

confidence: 99%

Contribution of polymeric materials to progress in xenotransplantation of microencapsulated cells: a review

Mahou

Passemard

Carvello

et al. 2016

Xenotransplantation

View full text Add to dashboard Cite

show abstract

“…Amphililic hydrogelators usually contain amide or hydroxy groups, which allow stabilization of fibers, etc., in the gelation process . Hydrogen bonding plays a major role particularly for organic gelators; and in hydrophobic gels or gel cavities, where water minimally competes, also in sol−gel transitions and in the transition between swollen and collapsed gel phases …”

Section: Interactionsmentioning

confidence: 99%

Supramolecular Interactions in Chemomechanical Polymers

2009

View full text Add to dashboard Cite

ConspectusMolecular recognition is the basis for the operation of most biological functions; outside of nature, it has also been developed to a high degree of sophistication within the framework of supramolecular chemistry. More recently, selective noncovalent interactions-which constitute molecular recognition-are being used in intelligent new materials that transform chemical signals into actions, such as the release of drugs. The presence of supramolecular binding sites allows chemomechanical polymers to operate as sensors and actuators within a single unit without the need for any additional devices such as transducers or power supplies.A polymer can be designed so that a particular chemical substance, most often in aqueous surroundings, will trigger either a large expansion or a large contraction, depending on the mechanism. The translation of binding energy into mechanical motion can, with a suitable arrangement of the materials in tubes or on flexible films, be harnessed for unidirectional drives, flow control, the liberation of drugs, or the uptake of toxic compounds, among other applications. Miniaturization of the polymer particles allows one to enhance both the sensitivity and speed of the response, which is of particular importance in sensing.The basis for the selective response to external effector compounds, such as metal ions, amino acids, peptides, or nucleotides, is their noncovalent interaction with complementary functions covalently bound to the polymer network. With suitable polymers, selectivity between structural isomers-and even between enantiomers-as triggers can be achieved. As with supramolecular complexes in solution, the underlying interactions in polymers comprise a variety of noncovalent binding mechanisms, which are not easy to distinguish and quantify-and more so with polymers, which are not monodisperse. In this Account, we present systematic comparisons of different polymers and effector classes that allow, for the first time, the characterization of these contributions in chemomechanical polymers: they comprise ion pairing, metal coordination, stacking, cation-π, dispersive, and hydrophobic forces. In contrast, hydrogen bonding has a major role primarily in the hydrogel network structure.The fully reversible polymer volume changes are essentially determined by water uptake or release. In gels derived from boronic acid, glucose can serve as a cross-linking effector in promoting contractions via strong, reversible covalent bond formation in a highly distinctive manner. Cooperativity between two different effector compounds is more frequently seen with such polymers than in solution: it leads to logical AND gates by different motions of the particles, with a direct communication link to the outside world. For example, with a polymer that bears several recognition sites, triggering peptides induce motion only if Zn 2+ or Cu 2+ ions are simultaneously present.The molecular recognition mechanisms that cause volume changes in polymers share similarities with extensively studied supram...

show abstract

Statistical theory for a hydrogen bonding fluid system of A a D d type (IV): Depletion potential between colloid particles

Wang

2012

Sci. China Chem.

View full text Add to dashboard Cite

Sol−Gel Transition in Nonlinear Hydrogen Bonding Solutions

Cited by 5 publications

References 39 publications

Contribution of polymeric materials to progress in xenotransplantation of microencapsulated cells: a review

Contribution of polymeric materials to progress in xenotransplantation of microencapsulated cells: a review

Supramolecular Interactions in Chemomechanical Polymers

Statistical theory for a hydrogen bonding fluid system of A a D d type (IV): Depletion potential between colloid particles

Contact Info

Product

Resources

About