Electron-Beam Lithography and Molecular Liftoff for Directed Attachment of DNA Nanostructures on Silicon: Top-down Meets Bottom-up

Abstract

CONSPECTUS: Our work on lithographic patterning of DNA nanostructures was inspired by a collaboration on molecular electronic devices known as quantum-dot cellular automata or QCA. QCA is a paradigm for computation in which information is transmitted and processed through the interaction of coupled electrical charges or magnetic dipoles. We began to explore the idea of molecular scale QCA and found that ab initio methods, a thermodynamic Ising model, and larger scale circuit design work suggested that circuits that did computationally interesting things could function at room temperature if made from molecular QCA cells of chemically reasonable design. But how could the QCA cells be patterned to form the complex arrays needed for computationally interesting circuitry, and how could those arrays of molecular circuitry be integrated with conventional electronic inputs and outputs? Top-down methods lacked the spatial resolution and high level of parallelism needed to make molecular circuits. Bottom-up chemical synthesis lacked the ability to fabricate arbitrary and heterogeneous structures tens to hundreds of nanometers in size. Chemical self-assembly at the time could produce structures in the right size scale, but was limited to homogeneous arrays. A potential solution to this conundrum was just being demonstrated in the late 1990s and early 2000s: DNA nanostructures self-assembled from oligonucleotides, whose high information density could handle the creation of arbitrary structures and chemical inhomogeneity. Our group became interested in whether DNA nanostructures could function as self-assembling circuit boards for electrical or magnetic QCA systems. This Account focuses on what we learned about the interactions of DNA nanostructures with silicon substrates and, particularly, on how electron-beam lithography could be used to direct the binding of DNA nanostructures on a variety of functional substrates.

Synthesis of ginsenoside Re-based carbon dots applied for bioimaging and effective inhibition of cancer cells

“…[13][14][15][16][17][18][19] The CDs synthesis methods are mainly of two modes: top-down and bottom-up. [20][21][22] Bottom-up carbonization synthesis methods, which are represented by calcination, high-temperature pyrolysis, microwave and hydrothermal synthesis, are thought to have obvious advantages in adjusting the composition and physical properties of CDs by carefully selecting the precursor sources and carbonization conditions, compared with the top-down methods. 23,24 When preparing CDs, organic carbon sources such as citric acid, glycerol, saccharides, amines, plants, fruit juice, proteinbased biopolymer and so on are widely applied because of the low cost, relatively moderate reaction conditions and environmental friendliness.…”

A Nonconventional Approach to Patterned Nanoarrays of DNA Strands for Template‐Assisted Assembly of Polyfluorene Nanowires

“…DNA have been capitalized on as a structural material to arrange organic and inorganic molecular components using DNA as a template has been demonstrated . DNA self‐assembly has attracted significant attention as it offers a bottom‐up manufacturing technique to provide efficient templates for the subsequent assembly of either organic or inorganic nanoelements such as metallic charged nanoparticles or streptavidin proteins . Surface modification of individual DNAs and their configurations is of crucial importance to develop nanoscale devices based on DNA‐templated assembly .…”

“…[5][6][7][8] DNA self-assembly has attracted signifi cant attention as it offers a bottom-up manufacturing technique to provide effi cient templates for the subsequent assembly of either organic or inorganic nanoelements such as metallic charged nanoparticles or streptavidin proteins. [9][10][11][12] Surface modifi cation of individual DNAs and their confi gurations is of crucial importance to develop nanoscale devices based on DNA-templated assembly. [ 13,14 ] In this context, the specifi c immobilization of a large number of DNA molecules on a solid substrate has progressed over the past years for many potential applications such as electronic, magnetic, optoelectronic, and sensors, in which DNA molecules are "addressable" only when they are highly ordered or stretched.…”

Clocked Quantum-dot Cellular Automata Circuits Tolerate Unwanted External Electric Fields

“…Some combination of self-assembly and lithography could one day provide suitable molecular circuit layout methods. [29][30][31] Layout technologies require further development, and we hope that this paper may provide some motivation for experimental efforts in this area.…”