Self-assembly of biocidal nanotubes from a single-chain diacetylene amine salt
ABSTRACT We describe the facile two-step synthesis of nanotubes that form pure, well-defined, nanostructured materials. We have synthesized a secondary amine HBr salt as the headgroup of a single-chain diacetylenic lipid. This molecule can form a number of different self-assembled nanostructures in aqueous or organic solvents. In water, this lipid forms a monodisperse preparation of nanotubes at high yields. Partially dissolving a preparation of nanotubes dried from aqueous solution results in a remarkably organized structure that resembles a nanocarpet. Details of the nanotube structure were investigated by scanning electron microscopy, transmission electron microscopy, and small-angle X-ray spectroscopy. The aqueous nanotubes have a cross-sectional diameter of 89 nm. The walls of the tubes are an exquisitely uniform 27 nm thick and are shown to consist of five lipid bilayers with a repeat spacing of 57.8 A. The chemical structure of the material shows no chiral centers, but suspensions of the nanotubes in an aqueous medium show an unexpected circular dichroism signal. The versatility of this new material as a platform for nanostructure design and synthesis is enhanced by its biocidal activity. This antimicrobial activity along with the regularity the nanostructures will enhance the development of a range of applications from biosensors to artificial retinas.
- SourceAvailable from: Saurabh Jyoti Sarma
Critical Reviews in Environmental Science and Technology 01/2015; · 3.47 Impact Factor
- "Likewise, in wastewater treatment plants, CNTs could be used to detect certain toxic compounds having heavy metal ions (Timur et al., 2007). Moreover, CNTs have antimicrobial properties (Lee et al., 2004; Kang et al., 2009b) and hence apart from concentration (by adsorption), they can kill any pathogen present in water/wastewater. Due to their antimicrobial properties , CNTs could be used to prevent biofouling of surfaces (Al-Hakami et al., 2013). "
[Show abstract] [Hide abstract]
- "Carbon nanotubes have high bacterial adsorption capacity   and are able to concentrate different types of pathogens   . This exceptionally high adsorption capacity of nanotubes is due to its large surface to volume ratio and high aspect ratio that imparts high antimicrobial nature to the material  . Another major advantage of using carbon nanotubes for water treatment applications is that nanotubes, if functionalized, have the ability to detect pathogens. "
ABSTRACT: The possibility of using single-walled carbon nanotubes (SWCNTs) aggregates as fluorescence sensors for pathogen recognition in drinking water treatment applications has been studied. Batch adsorption study is conducted to adsorb large concentrations of Staphylococcus aureus aureus SH 1000 and Escherichia coli pKV-11 on single-walled carbon nanotubes. Subsequently the immobilized bacteria are detected with confocal microscopy by coating the nanotubes with fluorescence emitting antibodies. The Freundlich adsorption equilibrium constant (k) for S.aureus and E.coli determined from batch adsorption study was found to be 9×108 and 2×108 ml/g, respectively. The visualization of bacterial cells adsorbed on fluorescently modified carbon nanotubes is also clearly seen. The results indicate that hydrophobic single-walled carbon nanotubes have excellent bacterial adsorption capacity and fluorescent detection capability. This is an important advancement in designing fluorescence biosensors for pathogen recognition in water systems.Research Letters in Nanotechnology 01/2008; DOI:10.1155/2008/156358
- "Single-walled carbon nanotubes possess antimicrobial properties (Kang et al. 2004; Lee et al. 2004) that enable them to effectively concentrate and deactivate pathogens from contaminated water. When bacteria come in physical contact with nanotubes, they penetrate through the cell membrane, disrupts its activity and eventually destroys the cell viability (Kang et al. 2007; Lee et al. 2004; Narayan et al. 2005). It was proposed that the cylindrical shape of nanotube fibers coupled with a high aspect ratio are mainly responsible for death of bacterial cells. "