Despite the continuous interest in organogels and hydrogels of low molecular weight gelators (LMWG), establishing the relationship between the molecular structure and the gelation mechanism is still a challenge. In this paper our interest focuses on the consequences of slight molecular modifications on the self-assembling behaviour of β-Ala vs Gly-Gly-based hydrogelators. Previously, in our gro...

This paper reports a simple, rapid, and sugar-selective method to induce gelation from glucose-containing samples. This method employs glucose oxidase (GOx) to selectively "recognize" and oxidize glucose to generate gluconic acid, which acts to solubilize calcium carbonate and release calcium ions. The release of calcium ions triggers gelation of the calcium-responsive polysaccharide alginate t...

We study a class of growth processes in which clusters evolve via exchange of particles. We show that depending on the rate of exchange there are three possibilities: (I) Growth-clusters grow indefinitely, (II) gelation-all mass is transformed into an infinite gel in a finite time, and (III) instant gelation. In regimes I and II, the cluster size distribution attains a self-similar form. The la...

We have studied the kinetics of the gelation process that occurs upon warming cold extracts of Acanthamoeba using a low-shear falling ball assay. We find that the reaction has at least two steps, requires 0.5 mM ATP and 1.5 mM MgCl2, and is inhibited by micromolar Ca++. The optimum pH is 7.0 and temperature, 25 degrees-30 degrees C. The rate of the reaction is increased by cold preincubation wi...

An in situ heparin-based forming hydrogel that cures under visible-light is formulated using eosin Y as a photoinitiator with triethanolamine as an electron donor to initiate reaction of thiolated-heparin with acrylate-ended poly(ethylene glycol). Formulations and irradiation conditions are presented for control of heparin content (1.6 to 3.3% w/v), modulus (100-10,000 Pa), and gelation time (3...

We experimentally and theoretically investigate the size effect of gelation using Resorcinol-Formaldehyde aerogels. We find a clear dependence of gelation time on the sample size under mild shear conditions. We developed a theoretical model based on Smoluchowski’s aggregation model adding, however, a growth term which accounts for the continuous growth of the colloidal particles while clusterin...

Kinetic arrest in colloidal dispersions with isotropic attractive interactions usually occurs through the destabilization of the homogeneous phase and the formation of a non-equilibrium network of jammed particles. Theory and simulations predict that a different route to gelation should become available when the valence of each colloidal particle is suitably reduced. Under these conditions, gel...

The purpose of the study was to develop an optimized thermoreversible in situ gelling ophthalmic drug delivery system based on Pluronic F 127, containing moxifloxacin hydrochloride as a model drug. A 3(2) full factorial design was employed with two polymers: Pluronic F 68 and Gelrite as independent variables used in combination with Pluronic F 127. Gelation temperature, gel strength, bioadhesio...

A chemically reactive hybrid diblock polypeptide gelator poly(ethylene glycol)-block-poly(dl-allylglycine) (PEG-b-PDLAG) is an exceptional material, due to the characteristics of thermo-reversible organogel formation driven by the combination of a hydrophilic polymer chain linked to a racemic oligomeric homopeptide segment in a range of organic solvents. One-dimensional stacking of the block co...

The thermal gelation of black marlin muscle proteins treated with electric pulses and air-blowing was examined in connection with protein denaturation. Though the thermal gelation curve of the muscle paste treated with air-blowing gave an induction period between the first air-blowing and the main acceleration of the reaction, the induction period disappeared on enhancing effect when electric p...