Layer-by-layer assembly as a versatile bottom-up nanofabrication technique for exploratory research and realistic application

Abstract

The layer-by-layer (LbL) adsorption technique offers an easy and inexpensive process for multilayer formation and allows a variety of materials to be incorporated within the film structures. Therefore, the LbL assembly method can be regarded as a versatile bottom-up nanofabrication technique. Research fields concerned with LbL assembly have developed rapidly but some important physicochemical aspects remain uninvestigated. In this review, we will introduce several examples from physicochemical investigations regarding the basics of this method to advanced research aimed at practical applications. These are selected mostly from recent reports and should stimulate many physical chemists and chemical physicists in the further development of LbL assembly. In order to further understand the mechanism of the LbL assembly process, theoretical work, including thermodynamics calculations, has been conducted. Additionally, the use of molecular dynamics simulation has been proposed. Recently, many kinds of physicochemical molecular interactions, including hydrogen bonding, charge transfer interactions, and stereo-complex formation, have been used. The combination of the LbL method with other fabrication techniques such as spin-coating, spraying, and photolithography has also been extensively researched. These improvements have enabled preparation of LbL films composed of various materials contained in well-designed nanostructures. The resulting structures can be used to investigate basic physicochemical phenomena where relative distances between interacting groups is of great importance. Similarly, LbL structures prepared by such advanced techniques are used widely for development of functional systems for physical applications from photovoltaic devices and field effect transistors to biochemical applications including nano-sized reactors and drug delivery systems.

Polyelectrolyte Layer-by-Layer Assembly To Control the Distance between Fluorophores and Plasmonic Nanostructures

“…[15][16][17][18][19] A detail understanding of the MEF and its distance dependence nature is vital for its potential application in biomedical sensing. [20][21][22] Layer-by-layer (LbL) assembly [23][24][25][26][27][28][29][30][31][32][33][34][35][36] is based on the sequential adsorption of polycations and polyanions from dilute aqueous solution onto a solid substrate as a consequence of the electrostatic interaction and complex formation between oppositely charged polyelectrolytes. Starting from a functionalized solid substrate, it is possible to adsorb a variety of charged species ranging from polyelectrolytes, nanoparticles, and ionic dyes to many biological agents such as viruses, proteins, and DNA.…”

Penicillin biosensor based on a capacitive field-effect structure functionalized with a dendrimer/carbon nanotube multilayer

“…Carbon nanotubes (CNTs) are attractive for (bio-)chemical sensors because of their unique properties, which in most cases arise from the combination of electrical and chemical properties and nanosized dimensions (Balasubramanian and Burghard, 2006;Kim et al, 2007;Allen et al, 2007;Byon and Choi, 2006). One simple, versatile method to assemble dispersed CNTs is the layer-by-layer (LbL) technique, which offers fine control over film thickness and architecture (Hammond, 2004;Tang et al, 2006;Ariga et al, 2007), making it possible to combine different materials in a synergistic way (Jiang et al, 2004;Olek et al, 2004;Zucolotto et al, 2006;Siqueira et al, 2006Siqueira et al, , 2007Xue et al, 2006;Zucolotto et al, 2007). As a building unit for the multilayer films in biosensors, CNTs have often been combined with polyelectrolytes and highly branched dendritic macromolecules (Yang et al, 2006;Siqueira et al, 2008;Siqueira et al, 2009).…”

Enzyme−DNA Biocolloids for DNA Adduct and Reactive Metabolite Detection by Chromatography−Mass Spectrometry

“…To address these issues, we explored a biocolloid approach pioneered by Lvov, Caruso, and co-workers 24 who used alternate electrostatic layer-by-layer (LbL) adsorption [25][26][27][28] to form active enzyme films of glucose oxidase, horseradish peroxidase, and urease on spherical nanoparticles. The small size of the biocolloids offers increased active surface area and tiny solution volumes to conserve enzyme and also to obtain more product per unit time for subsequent determination of major and minor products.…”