Nanoporous Anodic Alumina Platforms for Drug Delivery Applications: Recent Advances and Perspective

Abstract

dosages to maintain drug level in the body and there is usually a rapid release of the drug directly into the blood circulation within a short time before reaching the desirable site, which might possess a risk of damaging healthy organs. [3] The main problem with these types of delivery vehicles includes poor patient compliance, lack of selectivity, unavoidable drug solubility, and biodistribution along with unfavorable elution kinetics. [4] With recent advances in nanofabrication technologies, drug delivery systems have achieved a significant progress in terms of patient safety, bioavailability, and achieving required therapeutic efficiency. [5,6] Two new branches, i.e., localized drug delivery systems (LDDSs) and targeted drug delivery systems (TDDSs) have emerged to efficiently deliver a drug inside the body using many nano-based drug carriers. These carriers include nanoparticles, liposomes, dendrimers, micelles, nanospheres, nanotubes, graphene. [7-11] Both of these concepts have already been executed in clinical practices performing excellently in terms of cost-effectiveness, less painful technologies, controlled and reliable drug release profile. [12] Amidst different categories of nanomaterials developed for drug release, inorganic nanoporous structures are the center of attraction for most of the researchers today due to its ease of fabrication, cost-effectiveness, and ability to tune structural parameters precisely. [13] In recent years, nanoporous anodic alumina (NAA), porous silicon (pSi), and titania were thoroughly investigated among all nanoporous materials specifically for developing new drug-releasing strategies due to their excellent physiochemical properties and biocompatible properties. [14-16] Among all the materials mentioned above, NAA remains one of the best choices due to its excellent chemical inertness, biocompatibility, enhanced mechanical strength, tunable chemistry, and controlled pore dimensions and volumes for loading and releasing drugs in a controlled manner. [14,17-20] In addition to its biomedical importance, NAA is also being utilized in optical biosensing, energy production, and catalytic applications. [13,21-25] This review compiles the most recent advances in NAA platforms for drug delivery applications with a short introduction for efficient drug delivery strategies developed over the years. To start with, the fundamental fabrication process, their properties, and biocompatibility of NAA are briefly introduced. The main intention is to summarize the different nanostructures based on NAA currently being developed for drug delivery applications, their advantages, and limitations. Furthermore, For several decades, nanoporous anodic alumina (NAA) has been prepared through inexpensive electrochemical anodization of aluminum to prepare diversified periodically ordered nanostructures. It acts as an excellent drug reservoir due to its excellent physical and chemical properties hence minimizing the drug loss and increasing bioavailability to the target site. A rapid increase in ex...

Revisiting anodic alumina templates: from fabrication to applications

“…The characteristics of the porous alumina also make them good candidates as drug delivery systems, showing some advantages such a controlled drug release that can be sustained over long periods, with no observed bursting effects (where high doses of the load are released in an early stage), chemical stability of the alumina membranes and the bonus of the possibility of functionalizing the surface to promote the selective release (a review on this application can be found in 374 ). There has been reported dependence on the total drug load and diffusion kinetics of the subsequent drug release with pore geometry 21 .…”

Recent Advances in Nanoporous Anodic Alumina: Principles, Engineering, and Applications

“…NAA is attractive not only due to its impressive enormous surface area combined with high chemical and thermal resistance, but due to the range of robust functionalization processes such as salinization [ 42 ], electrostatic interaction [ 43 ], and immune complexation [ 44 ] that allow versatile utility of such substrates: Sensors [ 45 , 46 ], templates [ 47 ], or drug delivery systems [ 48 ].…”

“…In a recent review, drug delivery perspectives, providing an update to the state of the art of NAA and NAA-derived materials in the field were discussed by Kapruwan et al [ 48 ].…”

Optical Platform to Analyze a Model Drug-Loading and Releasing Profile Based on Nanoporous Anodic Alumina Gradient Index Filters

“…Recent years have seen tremendous growth in the design and engineering of nanoporous structures based on modified anodization strategies. Therefore, it is possible now to control light-matter interaction and to fabricate advanced structures to be used in a broad range of applications in the field of biosensing [ 1 , 2 , 3 , 4 ], drug delivery [ 5 , 6 , 7 ], and photocatalysis [ 8 , 9 ]. Nanoporous anodic alumina photonic crystals (NAA-PCs) fall under the regime of optical materials having light modulation capabilities within the spectral regions (from Ultra-Violet to Infra-Red) allowing easy transport of molecules.…”