Nanoscale γ-AlO(OH) Hollow Spheres:  Synthesis and Container-Type Functionality

Abstract

AlO(OH) hollow spheres are realized via a water-in-oil (w/o) microemulsion, applying the liquid-to-liquid-phase boundary of the micellar system as a template. Scanning electron microscopy, transmission electron microscopy (TEM), and dynamic light scattering analyses show the presence of nonagglomerated hollow spheres exhibiting an outer diameter of about 30 nm and a wall thickness of 5-6 nm. High-resolution TEM images show highly ordered lattice fringes, indicating the crystallinity of the sphere wall and identifying the wall to consist of gamma-AlO(OH) (boehmite). The container functionality of as-prepared AlO(OH) hollow spheres is validated as a proof of concept by encapsulating the fluorescent dye rhodamine (R6G) inside the alumina shell. Subsequent to centrifugation and careful purification, R6G is evidenced via photoluminescence to be still present. Finally, release of R6G is initiated by acidic dissolution of the sphere wall.

Hollow Micro‐/Nanostructures: Synthesis and Applications

“…[175] Most recently, Feldmann and co-worker synthesized boehmite (g-AlO(OH)) hollow nanospheres through hydrolysis of Al(sec-OC 4 H 9 ) 3 via a W/O (n-dodecane) emulsion templating route. [160] The emulsion droplets are stabilized by CTAB. As a result, the as-prepared boehmite hollow nanospheres with size of about 30 nm are quite uniform and nonagglomerated (see Fig.…”

“…Second, the high deformability of the droplets should allow them to accommodate larger levels of shrinkage, which reduces cracking and pulverization during post-treatments such as drying and calcination. More importantly, templating against liquid droplets allows facile and efficient introduction of functional liquid cores or species like therapeutic and DNA molecules inside the capsule, [160,167,169,170,173,174] which is particularly attractive in drug delivery and pharmaceutical applications. In practice, controlling the size, uniformity, and interfacial reactions in emulsion droplets remains a serious challenge.…”

The use of aluminum and its compounds in the biomedical purposes

“…Дослідження методом фотолюмінесценції показали, що такі сфери -стійкий засіб транспорту діючої речовини, що витримує центрифугування. Така речо-вина вивільнюється у разі впливу на міцелу органічних кислот [5]. На основі сполук наноалюмінію створено каркасні таблетки з пролонгованою дією, що забезпечують точне, тривале та контрольоване дозування хіміч-них реагентів і каталізаторів для доставки в організм.…”

Solvothermal Synthesis and Characterization of Hierarchically Nanostructured Hydroxyapatite Hollow Spheres

“…[12] Up to now, a variety of hollow spheres such as TiO 2 , [13] Cu 2 O, [14] WO 3 , [15] MnS, [16] and In 2 S 3 [17] have been reported. Various methods including coprecipitation, microemulsion, [18] ultrasound irradiation, hydrothermal method, [19] and thermal decomposition of organometallic compounds have been applied in producing the hollow sphere structures.…”