The use of oxanorbornane-based sugar-like surfaces in the development of new amphiphilic systems is demonstrated. Crystallographic analysis and results from aggregation studies showed their close resemblance to glycolipids. © The Royal Society of Chemistry 2012.

Kannoth Manheri Muraleedharan

Department Of Chemistry

Muthupandian Ganesan

AMPHIPHILIC SYSTEMS

CRYSTALLOGRAPHIC ANALYSIS

Glycolipids

Material property

Sugars

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

RSC Advances

Chirality

1-Hydroxymethyl-7-oxabicyclo[2.2.1]hept-2-ene skeleton in enantiopure form through enzymatic kinetic resolution

Interfacial hydrolysis of oxanorbornane-based amphiphile (Triol C16) by Candida rugosa lipase was investigated using real-time polarized Fourier transform-infrared reflection absorption spectroscopy (FT-IRRAS). The kinetics of hydrolysis was studied by analyzing the ester carbonyl ν(C[dbnd]O) stretching vibration band across the two dimensional (2D) array of molecules at the confined interface. In particular, we demonstrate Triol C16 to form Michaelis-Menten type complex, like that of lipid-substrate analogues, where the Triol C16 head group remained accessible to the catalytic triad of the lipase. The enzyme-induced selective cleavage of the ester bond was spectroscopically monitored by the disappearance of the intense ν(C[dbnd]O) resonance at 1736 cm−1. Consequently, the in situ spectroscopic measurements evidenced selective ester hydrolysis of Triol C16 yielding Tetrol C2OH and Palmitic acid, which remained predominantly in the undissociated form at the interface. The conformation sensitive amide I (majorly ν(C[dbnd]O)) and the interfacial water reorganization suggested 2D ordering of the enzyme molecules following which interfacial reactions were employed towards probing the enzyme kinetics at the air/water interface. The investigation demonstrated further the potential of IRRAS spectroscopy for real-time monitoring the hydrolytic product formation and selectivity at biomimetic interfaces. © 2017 Elsevier B.V.

Chemistry and Physics of Lipids

Regio-selective lipase catalyzed hydrolysis of oxanorbornane-based sugar-like amphiphiles at air–water interface: A polarized FT-IRRAS study

The self-assembly of non-ionic amphiphiles with a hydroxylated oxanorbornane head-group was controlled using amino acid units as spacers between hydrophilic and lipophilic domains to get spherical supramolecular aggregates. The ability of these systems to harbour therapeutic agents like ibuprofen, and their drug-release profiles were evaluated. Apart from directing the assembly, the intervening amino acid unit was found to help in drug entrapment as well. The presence of cholesterol improved their drug-loading ability, and an encapsulation efficiency of up to 66% was shown by the formulation containing the phenylalanine residue as the spacer (NC1c). There was no burst release, and 45% drug release was observed at the end of 24 h in this case (cf. soyaphosphatidylcholine based formulation = 49%). The results from SEM, Cryo-TEM, PXRD and confocal microscopic studies with some insights into molecular packing in this class of aggregates are also included. © The Royal Society of Chemistry.

Journal of Materials Chemistry B

A modular approach towards drug delivery vehicles using oxanorbornane-based non-ionic amphiphiles

An amphiphilic oxanorbornane skeletal frame has been efficiently organized to direct the formation of dimensionally controllable, geometry-specific nanostructures as diverse as 0-D surface/reverse micelles, 1-D nanofibers, 2-D rectangular/square sheets, and 3-D flowers. The racemate with its precise stereo-projection of the -OH groups and the ring oxygen could be used for Li+ ion sensing and aided in the formation of pre-micellar aggregates of conventional surfactants. © 2014 The Royal Society of Chemistry.

Fulltext

Tailoring strained oxanorbornane headgroups to dimensionally controlled nanostructures through hydrogen bonding

Achiral amphiphiles with hydroxylated oxanorbornane headgroups showed specific morphological characteristics and hierarchical preferences depending upon the nature of lipophilic units. Detailed scanning electron microscopic (SEM) studies showed that twisted ribbonlike aggregates are characteristic of monoalkoxyaryl lipids with hydrocarbon chain length in the range C10-C13; these systems also had a preference toward lamellar arrangement. Asymmetric packing of these lipids is a unique occurrence and shows that the presence of molecular chirality is not an absolute requirement for curvature effects in their supramolecular assemblies. Aryl units in these systems were found to be important for the observed morphological preferences, which became evident from comparative studies involving simple long chain esters without this moiety. Single-crystal X-ray diffraction analysis of one of the lipids from the latter group gave finer details of strong and weak secondary interactions, which operate during their assembly process. Introduction of more than one alkyl chain on the aromatic ring caused a notable shift in the packing propensity toward columnar arrangement. Most of these cone-shaped molecules were found to give doughnut-shaped aggregates from acetone solution through the intermediary of fibrous structures, which was confirmed through SEM, transmission electron microscopic, and atomic force microscopic studies. © 2013 American Chemical Society.

Langmuir

Hierarchical preferences of hydroxylated oxanorbornane-based achiral amphiphiles

Liquid Crystals

What makes a liquid crystal? The effect of free volume on soft matter

Angewandte Chemie International Edition

Cover Picture: Unprecedented Molecular Architectures by the Controlled Self-Assembly of a β-Peptide Foldamer (Angew. Chem. Int. Ed. 44/2010)

Inside Cover: Polyhedral Organic Microcrystals: From Cubes to Rhombic Dodecahedra (Angew. Chem. Int. Ed. 48/2009)

European Journal of Organic Chemistry

Archaeal Lipids: Innovative Materials for Biotechnological Applications

Journal of the American Chemical Society

Growth of Narrowly Dispersed Porphyrin Nanowires and Their Hierarchical Assembly into Macroscopic Columns

Oxanorbornane-based amphiphilic systems: Design, synthesis and material properties

Journal	RSC Advances
ISSN	20462069
Open Access	No