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Water Gelation of an Amino Acid-Based Amphiphile

Authors

  • Debapratim Das,

    1. Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India, Fax: (+91) 33-2473-2805
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  • Antara Dasgupta,

    1. Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India, Fax: (+91) 33-2473-2805
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  • Sangita Roy,

    1. Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India, Fax: (+91) 33-2473-2805
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  • Rajendra Narayan Mitra,

    1. Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India, Fax: (+91) 33-2473-2805
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  • Sisir Debnath,

    1. Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India, Fax: (+91) 33-2473-2805
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  • Prasanta Kumar Das Dr.

    1. Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India, Fax: (+91) 33-2473-2805
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Abstract

The water immobilization by a simple amino acid-containing cationic surfactant was investigated. A variety of techniques, such as 1H NMR spectroscopy, circular dichroism (CD), steady-state fluorescence spectroscopy, and field-emission scanning electron microscopy (FESEM) were applied to determine the formation and architecture of the hydrogel. The new gelator with a minimum gelation concentration (MGC) of 0.3 % w/v shows prolonged stability and a low melting temperature (39 °C). 1H NMR experiments revealed that intermolecular hydrogen bonding between the amide groups and π–π stacking of the indole rings are the two regulating parameters for gelation. Furthermore, fluorescence studies with 8-anilino-1-naphthalenesulfonic acid (ANS) as the probe indicate the participation of hydrophobicity during gelation. The luminescence study using both ANS and pyrene, along with FESEM results, indicate a critical concentration, well below the MGC, at which fibres begin to form. These cross-link further to give thicker fibers, leading to the formation of a hydrogel (0.3 % w/v). This new hydrogelator expresses high supramolecular chirality, as evidenced by the CD spectra. In addition, the gelator molecule was found to be nontoxic up to a concentration of 4 mM (0.2 % w/v). The high supramolecular chirality, prolonged stability, low melting point, and biocompatibility of the molecule make it a focus of chemical and biological interest.

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