Layer-by-layer assemblies in nanoporous templates: nano-organized design and applications of soft nanotechnology

Abstract

The synergistic combination of layer-by-layer (LbL) assembly and nanoporous membrane templating has greatly facilitated the creation of complex and functional nanotubular structures. The approach takes advantage of both the new properties conferred by assembling diverse LbL building blocks and the tight dimensional control offered by nanotemplating to enable new functionalities that arise from the highly anisotropic “one-dimensional” LbL-nanotube format. In this review, we aim to convey the key developments and provide a current snap-shot of such templated LbL nanoarchitectures. We survey recent developments that have enabled the assembly of polymers, biomolecules and inorganic nanoparticles “à la carte”, via electrostatic, covalent and specific (bio)recognition interactions. We also discuss the emerging mechanistic understanding of the LbL assembly process within the nanopore environment. Finally, we present a diverse range of LbL nanotube “devices” to illustrate the versatility of the nanotemplated LbL toolbox for generating functional soft nanotechnology.

Spherical and tubule nanocarriers for sustained drug release

“…The nanocarrier aspect ratio has been recognized as a factor affecting cellular interaction and biodistribution of drug vehicle [25]. For fabrication of polyelectrolyte nanotubes, sacrificial nanoporous anodic aluminum oxide and track-etched polymer membranes with a pore diameter of 200–400 nm and pore lengths from hundreds of nanometers to tens of microns are used [26]. Arrays of tubules incorporating cytochrome C, collagen, peroxidase, HSA, ferritin, myoglobin, were fabricated using synthetic polyelectrolytes as alternated building blocks [27].…”

Adsorptive removal of Mn(II)–Mn(VII) from various aqueous and nonaqueous solutions by using layer-by-layer chemical deposition technique

“…In addition, LbL has been also examined and successfully used for synthesis of several important classes of nano-compounds and nano-materials via thin film formation [21][22][23][24][25][26][27][28]. The description of this technique for thin film formation of various nano-materials was previously reported [22][23][24] and recently discussed in static removal of some heavy metal ions from various matrices [19,20].…”

Effects of geometrical confinement in membrane pores on enzyme-based layer-by-layer assemblies

“…Therefore, different architectures such as protein planar films and coated microparticles, hollow capsules, coated membranes and nanotubes have been prepared. While most of the LbL research has been performed on planar or spherical surfaces, some groups also investigated deposition in membranes with cylindrical pores [20][21][22][23][24][25][26][27][28][29][30].…”

“…As originally described [6,7], LbL assembly consists of the alternate adsorption of a polyanion and a polycation onto oppositely charged surfaces. In the last twenty years, a variety of biomolecules e.g., proteins, virus, colloids and polysaccharides, have been incorporated in LbL films [3,[8][9][10][11].…”