Biomimetic Synthesis of Hierarchically Porous Nanostructured Metal Oxide Microparticles—Potential Scaffolds for Drug Delivery and Catalysis

Abstract

Hierarchically porous hybrid microparticles, strikingly reminiscent in their structure of the silica skeletons of single-cell algae, diatoms, but composed of titanium dioxide, and the chemically bound amphiphilic amino acids or small proteins can be prepared by a simple one-step biomimetic procedure, using hydrolysis of titanium alkoxides modified by these ligands. The growth of the hierarchical structure results from the conditions mimicking the growth of skeletons in real diatoms--the self-assembly of hydrolysis-generated titanium dioxide nanoparticles, templated by the microemulsion, originating from mixing the hydrocarbon solvent and water on action of amino acids as surfactants. The obtained microsize nanoparticle aggregates possess remarkable chemical and thermal stability and are promising substrates for applications in drug delivery and catalysis. They can be provided with pronounced surface chirality through application of chiral modifying ligands. They display also high selectivity in sorption of phosphorylated biomolecules or medicines as demonstrated by (1)H and (31)P NMR studies and by in vitro modeling using (32)P-marked ATP as a substrate. The release of the adsorbed model compounds in an inert medium is a very slow process directed by desorption kinetics. It is enhanced, however, noticeably in contact with biological fluids modeling those of the tissues suffering inflammation, which makes the produced material highly attractive for application in medical implants. The developed synthetic approach has been applied successfully also for the preparation of analogous hybrid microparticles based on zirconium dioxide or aluminum sesquioxide.

Cellulose nanofiber–titania nanocomposites as potential drug delivery systems for dermal applications

“…In this work, we used titania nanoparticles for cellulose nanofibers modification. Strong binding of 33 P-marked ATP with the surface of CNF_TiO 2 sample was also observed, as in pure titania microparticles 31 (Fig.8b). In particular, 33 P-marked ATP 1nM associated and reached the equilibrium with the sample in 10 h and in more than 21.5 h for 3nM 33 P-ATP.…”

“…In the form of small nanoparticles, the titania is known to be highly bio-digestible, 59 transforming in biological fluids (containing normally appreciable concentrations of chelating carboxylate ligands such as citrate and lactate) into soluble and non-toxic carboxylato-titanate species. 31,32,59 Conclusions…”

“…The measurements of uptake and release from pure cellulose nanofibers and nanocomposite based on titania and cellulose nanofibers were performed by Ridgeview Instrument AB, exploiting Ligand Tracer TM White technology, using 33 P-labeled (ATP) (adenosine 5''-triphosphate, substitution on γ-phosphorus atom, 1 ml of solution with 1mCurie total β-activity)as model compound 30,31 . A part of sample was deposited on a PMMA Petri dish as dispersion in toluene and immobilized by drying in air.…”

Synthesis of porous NiO nanocrystals with controllable surface area and their application as supercapacitor electrodes

“…Porous nanostructures have received great attention because of their wide-ranging applications, such as in lithium-ion batteries [1][2][3], ion exchange membranes [4], catalysis supports [5][6][7][8], solar cells [9], and supercapacitor electrodes [10][11][12][13][14] due to their high surface area and enhanced interaction with the environment [15]. In the case of charge storage applications, transition metal oxide nanostructures are attractive candidates by virtue of their excellent pseudocapacitive behavior and high electrical conductivity [16][17][18][19][20][21].…”

Synthesis and Characterization of Phase Pure NiO Nanoparticles via the Combustion Route using Different Organic Fuels for Electrochemical Capacitor Applications

“…The common electrode materials which are recently use in electrochemical capacitors are carbon, transition metal oxides and conducting polymers. Nanostructured materials are gaining a great interest due to their wide applications in various fields such as lithium-ion batteries [3][4][5], ion exchange membranes [6], catalysis supports [7][8][9][10], solar cells [11] and supercapacitor electrodes [12][13][14][15][16][17].…”