Article

Halloysite clay nanotubes for controlled release of protective agents

Institute for Micromanufacturing, Louisiana Tech University, Ruston, Louisiana, USA.
ACS Nano (Impact Factor: 12.03). 06/2008; 2(5):814-20. DOI: 10.1021/nn800259q
Source: PubMed

ABSTRACT Halloysite aluminosilicate nanotubes with a 15 nm lumen, 50 nm external diameter, and length of 800 +/- 300 nm have been developed as an entrapment system for loading, storage, and controlled release of anticorrosion agents and biocides. Fundamental research to enable the control of release rates from hours to months is being undertaken. By variation of internal fluidic properties, the formation of nanoshells over the nanotubes and by creation of smart caps at the tube ends it is possible to develop further means of controlling the rate of release. Anticorrosive halloysite coatings are in development and a self-healing approach has been developed for repair mechanisms through response activation to external impacts. In this Perspective, applications of halloysite as nanometer-scale containers are discussed, including the use of halloysite tubes as drug releasing agents, as biomimetic reaction vessels, and as additives in biocide and protective coatings. Halloysite nanotubes are available in thousands of tons, and remain sophisticated and novel natural nanomaterials which can be used for the loading of agents for metal and plastic anticorrosion and biocide protection.

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Available from: Yuri M Lvov, Nov 17, 2014
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    • "However, a report exists on the chemical deposition of cobalt nanoparticles on the surface of HNT [28]. Moreover, an overall improvement in the performance of HNT–nanoparticle composite nanofilms by the adsorption of organic macroions on surface-modified HNT has been described by several researchers [29] [30]. It has also been used as a substrate to fabricate a one-dimensional nanocomposite [31]. "
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    ABSTRACT: The study aims to investigate the effect of the addition of nanotubes of halloysite on the augmentation of chains observed in an aqueous magnetic fluid consisting of co-precipitated magnetite particles stabilized with lauric acid. Three samples of the mixture containing 0.5%, 1% and 2% of halloysite nanotubes (HNTs) and a pure magnetic fluid are used for this study. A room temperature magnetization study shows that for 0.5% and 1% of HNT, the magnetization of the mixture significantly increases, while for the higher concentration (2%) it decreases. Such concentration dependent behaviour on the addition of a nonmagnetic system to a magnetic fluid has not previously been observed. The increase in the magnetization is attributed to smaller sized (<5–6 nm) magnetite attached to the HNT, forming a magnetite–HNT composite. Additionally, field-induced chaining is augmented by the addition of HNT in the magnetic fluid. The augmentation of chain formation is confirmed by optical microscopy, field-induced transmission changes and field-dependent diffraction effects. The augmentation will be useful in enhancing other properties of the composite, such as the viscosity and thermal conductivity of nanofluids.
    Journal of Physics D Applied Physics 04/2014; 47(16):165501. DOI:10.1088/0022-3727/47/16/165501 · 2.72 Impact Factor
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    • "The result demonstrated that Hal was cytocompatible and could be potentially used as biomaterials. As an alternative one-dimensional nanoparticles for CNT, Hal was cheap, abundantly available, environmental-friendly, mechanically strong and biocompatible (Lvov et al., 2008; Qiao et al., 2012). Therefore, using Hal for preparing biocompatible and biodegradable CPN was significant both in theory and practice (Cavallaro et al., 2011a,b). "
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    ABSTRACT: Naturally occurred halloysite (Hal) nanotubes compounded with polylactide (PLA) via melt mixing formed biodegradable and biocompatible clay polymer nanocomposites (CPN). The hydrogen bonding interactions between Hal and PLA were confirmed by Fourier transform infrared spectroscopy (FTIR). The modulus, strength and toughness of the Hal-PLA nanocomposites were substantially higher than those of neat PLA. Storage modulus and glass transition temperature of the Hal-PLA nanocomposites also increased with Hal loading as observed by dynamic mechanical analysis. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results showed that Hal was uniformly dispersed and oriented in the CPN. X-ray diffraction (XRD) of the CPN showed the absence of Hal reflection at around 20°, indicating interactions of the PLA molecular chains in the interlayer space of Hal. Hal could nucleate PLA, leading to the decreased cold crystallization temperature and increased crystallinity. The vicat softening temperature and the degradation temperature of the CPN increased with Hal loading. Owing to the high performance and biocompatibility of the CPN, the prepared Hal-PLA nanocomposites had potential applications in biodegradable plastic and biomedical areas.
    Applied Clay Science 05/2013; s 75–76:52–59. DOI:10.1016/j.clay.2013.02.019 · 2.70 Impact Factor
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    • "Halloysite is reported to be a kind of promising drug delivery vehicle because of its good biocompatibility and the hollow tubular structure [28] [29] [30]. "
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    ABSTRACT: Fabrication of nanofiber-based drug delivery system with controlled release property is of general interest in biomedical sciences. In this study, we prepared an antibiotic drug tetracycline hydrochloride (TCH)-loaded halloysite nanotubes/poly(lactic-co-glycolic acid) composite nanofibers (TCH/HNTs/PLGA), and evaluated the drug release and antibacterial activity of this drug delivery system. The structure, morphology, and mechanical properties of the formed electrospun TCH/HNTs/PLGA composite nanofibrous mats were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and tensile testing. We show that the incorporation of TCH-loaded HNTs within the PLGA nanofibers is able to improve the tensile strength and maintain the three-dimensional structure of the nanofibrous mats. In vitro viability assay and SEM morphology observation of mouse fibroblast cells cultured onto the fibrous scaffolds demonstrate that the developed TCH/HNTs/PLGA composite nanofibers are cytocompatible. More importantly, the TCH/HNTs/PLGA composite nanofibers are able to release the antibacterial drug TCH in a sustained manner for 42 days and display antimicrobial activity solely associated with the encapsulated TCH drug. With the improved mechanical durability, sustained drug release profile, good cytocompatibility, and non-compromised therapeutic efficacy, the developed composite electrospun nanofibrous drug delivery system may be used as therapeutic scaffold materials for tissue engineering and drug delivery applications.
    Colloids and surfaces B: Biointerfaces 04/2013; 110C:148-155. DOI:10.1016/j.colsurfb.2013.04.036 · 4.15 Impact Factor
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