Fine-Tuning of Molecular Structures to Generate Carbohydrate Based Super Gelators and Their Applications for Drug Delivery and Dye Absorption

Abstract

Carbohydrate-based low molecular weight gelators (LMWGs) exhibit many desirable properties making them useful in various fields including applications as drug delivery carriers. In order to further understand the structural connection to gelation properties, especially the influence of halide substitutions, we have designed and synthesized a series of para-chlorobenzylidene acetal protected D-glucosamine amide derivatives. Fifteen different amides were synthesized, and their self-assembling properties were assessed in multiple organic solvents, as well as mixtures of organic solvents with water. All derivatives were found to be gelators for at least one solvent and majority formed gels in multiple solvents at concentrations lower than 2 wt%. A few derivatives rendered remarkably stable gels in aqueous solutions at concentrations below 0.1 wt%. The benzamide 13 formed gels in water and in EtOH/H2O (v/v 1:2) at 0.36 mg/mL. The gels were characterized using optical microscopy and atomic force microscopy, and the self-assembly mechanism was probed using variable temperature 1H-NMR spectroscopy. Gel extrusion studies using H2O/DMSO gels successfully printed lines of gels on glass slides, which retained viscoelasticity based on rheology. Gels formed by the benzamide 13 were used for encapsulation and the controlled release of chloramphenicol and naproxen, as well as for dye removal for toluidine blue aqueous solutions.

Recent advances in carbohydrate-based gelators

“…The self-assembling characteristics of these amides were examined in a variety of solvents, organics as well as mixtures, which revealed the property of these derivatives to form gels at low minimum gelation concentrations (MGCs) even below 0.1 wt%. The exploration resulted in the formation of a highly stable gel in water and EtOH/H 2 O by a gelator 128 benzamide 105 (Fig. 65) at an extremely low concentration of 0.04 wt%.…”

Structure–gelation property relationships of phenolic glycosides of pentose sugars: pH dependent controlled release of curcumin

“…Organogels have been explored as media for the controlled release of drugs for some time. [33][34][35][36] This application can be attributed to the fact that as smart materials organogels are responsive to various stimuli which can be used to trigger the release of the entrapped drugs. Such applications are mainly restricted to organogels of amino acids [37][38][39][40] and peptides, 41 phospholipids, 42 fatty acids 43 and their derivatives, 44 steroids 45 and alkylamides.…”

Synthesis and bioactivity of pyrrole-conjugated phosphopeptides

“…Biomacromolecular assemblies have received considerable attention recently in the field of biomaterials [1][2][3][4][5][6][7], among which peptides are of particular interest because of their unique merits, such as ease of design and tailoring (based on the known structures from proteins), good biocompatibility and degradability, and low immunogenicity. For example, recent works have demonstrated the potential of peptide assemblies for a wide range of applications, including drug delivery [8][9][10][11], collagen mimic [12], antibacterial [13,14], biomineralization [15,16], mimicry of amyloids [17], cell cultures [18], and tissue engineering [19].…”