title: Composite microparticles of halloysite clay nanotubes bound by calcium carbonate.
abstract: Natural halloysite clay nanotubes with 15 nm inner and 75 nm outer diameters have been used as vehicles for sustained release of drugs in composite hollow microparticles "glued" with CaCO3. We used a layer-by layer assembly accomplished alginate binding with Ca(2+) followed by CO2 bubbling to prepare the composite microspheres of CaCO3 and polyelectrolytes (PE) modified halloysite nanotubes (HNTs-PE2/CaCO3) with the diameter of about 5-10 μm. These microparticles have empty spherical structure and abundant pore distributions with maxima at 2.5, 3.9, 6.0 and 13.3 nm, and higher surface area of 82.3 m(2) g(-1) as characterized by SEM and BET test. We loaded drugs in these micro-nano carriers of tight piles of halloysite nanotube with end clogged with CaCO3. The sustained release of Nifedipine drug from HNTs-PE2/CaCO3 composite microspheres was slower than for pristine halloysite nanotubes.
authors.affiliation: Institute of Chemical Engineering, Ningbo University of Technology, Ningbo 315016, China. Electronic address: jinyimail@163.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Institute for Micromanufacturing, Louisiana Tech University, Ruston, Louisiana 71272, USA.
authors.forename: Raghuvara
authors.initials: R
authors.lastname: Yendluri
authors.affiliation: Institute of Chemical Engineering, Ningbo University of Technology, Ningbo 315016, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.affiliation: Institute of Chemical Engineering, Ningbo University of Technology, Ningbo 315016, China.
authors.forename: Jingbo
authors.initials: J
authors.lastname: Wang
authors.affiliation: Institute for Micromanufacturing, Louisiana Tech University, Ruston, Louisiana 71272, USA; Ural Federal University, Ekaterinburg 620002, Russia. Electronic address: ylvov@latech.edu.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Lvov
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D002119:Calcium Carbonate / Q000737:chemistry*; D000077215:Clay; D043942:Nanotubes / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D000538:Aluminum Silicates; D002119:Calcium Carbonate; D000077215:Clay
keywords: Calcium carbonate; Drug sustained release; Halloysite; LbL self-assembly