Inorganic nanolayers: structure, preparation, and biomedical applications

Abstract

Hydrotalcite-like compounds are two-dimensional inorganic nanolayers also known as clay minerals or anionic clays or layered double hydroxides/layered hydroxy salts, and have emerged as a single type of material with numerous biomedical applications, such as drug delivery, gene delivery, cosmetics, and biosensing. Inorganic nanolayers are promising materials due to their fascinating properties, such as ease of preparation, ability to intercalate different type of anions (inorganic, organic, biomolecules, and even genes), high thermal stability, delivery of intercalated anions in a sustained manner, high biocompatibility, and easy biodegradation. Inorganic nanolayers have been the focus for researchers over the last decade, resulting in widening application horizons, especially in the field of biomedical science. These nanolayers have been widely applied in drug and gene delivery. They have also been applied in biosensing technology, and most recently in bioimaging science. The suitability of inorganic nanolayers for application in drug delivery, gene delivery, biosensing technology, and bioimaging science makes them ideal materials to be applied for theranostic purposes. In this paper, we review the structure, methods of preparation, and latest advances made by inorganic nanolayers in such biomedical applications as drug delivery, gene delivery, biosensing, and bioimaging.

Synthesis and characterization of protocatechuic acid-loaded gadolinium-layered double hydroxide and gold nanocomposite for theranostic application

“…The correlation coefficients (R 2 ) of the three models were deduced from the graphs and are presented in Table 1 along with rate constant (K), percentage saturation (%) and t 1∕2 (min) of the sample in both pHs. The drug kinetic release data like several other reported kinetic release data of some drugs from different nano-carriers, was observed to have matched best to the pseudo-second order (Bullo and Hussein 2015;Bullo et al 2013;Dorniani et al 2012Dorniani et al , 2014Tan et al 2014), with R 2 value of 0.982 ( Fig. 4) against 0.560 and 0.695 for pseudo-first order and parabolic diffusion, respectively, in pH 4.8.…”

“…The profiles were obtained by matching the absorbances from the release, which are expressed in percentage against time of release; the release in both pHs varies at both time of release as well as the percentage of release. Although it is quite common and expected for guest molecules intercalated within LDH gallery to release more in the acidic medium than in the alkaline medium (Bullo and Hussein 2015;Usman et al 2017a, b), as observed in this case (98% at pH 4.8 and 20% at pH 7.4), it is, however, uncommon for the intercalated guest to vary in period of release at different pHs. As can be observed in Fig.…”

“…Cancer related diseases have being steadily on the rise globally with an annual increase (WHO cancer 2017; Yuan et al 2017). Nano-based carriers have been used in the delivery of various anticancer agents (Bullo and Hussein 2015), because of their benefits of passive accumulation in the cancer cells via enhanced permeability and retention effect (EPR) (Duc et al 2014). The effect also favors its use in theranostic delivery system (TDS).…”

Gadolinium-Doped Gallic Acid-Zinc/Aluminium-Layered Double Hydroxide/Gold Theranostic Nanoparticles for a Bimodal Magnetic Resonance Imaging and Drug Delivery System

“…Zn/Al-layered double hydroxide (LDH) is one of the candidates capable of simultaneously intercalating and adsorbing theranostic agents due to their exchangeable interlayer anions. LDH is one of the group of two-dimensional layered structures materials [ 13 ] and has the general formula of [ (OH) 2 ] x + [A n − ] x / n · m H 2 O] [ 14 ], where divalent and trivalent metal cations are represented by M 2+ and M 3+ , respectively, and interlayer exchangeable anions are represented by [A n − ], and water as x / n [ 8 , 15 , 16 , 17 ]. Gallic acid is the therapeutic agent employed in this research; it is a naturally occurring polyhydroxyl phenolic compound, often found in different kinds of fruits.…”

Functionalization of Surfaces in Layered Double Hydroxides and Hydroxide Salt Nanoparticles

“…This fraction determines the electrostatic charge density in the layers, thus influencing the size of the interlayer space and a variety of physicochemical properties such as adhesion, reactivity, ion-exchange capacity, and rotation of chemical species into the interlayer space and on the surface [7]. More details related to the structure of LDH can be found in some published revisions [9,10].…”