Hanson, K. L., Fulga, F., Dobroiu, S., Solana, G., Kašpar, O., Tokárová, V., Nicolau, D. V.

Polymer surface properties control the function of heavy meromyosin in dynamic nanodevices

Abstract

The actin-myosin system, responsible for muscle contraction, is also the force-generating element in dynamic nanodevices operating with surface-immobilized motor proteins. These devices require materials that are amenable to micro- and nano-fabrication, but also preserve the bioactivity of molecular motors. The complexity of the protein-surface systems is greatly amplified by those of the polymer-fluid interface; and of the structure and function of molecular motors, making the study of these interactions critical to the success of molecular motor-based nanodevices. We measured the density of the adsorbed motor protein (heavy meromyosin, HMM) using quartz crystal microbalance; and motor bioactivity with ATPase assay, on a set of model surfaces, i.e., nitrocellulose, polystyrene, poly(methyl methacrylate), and poly(butyl methacrylate), poly(tert-butyl methacrylate). A higher hydrophobicity of the adsorbing material translates in a higher total number of HMM molecules per unit area, but also in a lower uptake of water, and a lower ratio of active per total HMM molecules per unit area. We also measured the motility characteristics of actin filaments on the model surfaces, i.e., velocity, smoothness and deflection of movement, determined via in vitro motility assays. The filament velocities were found to be controlled by the relative number of active HMM per total motors, rather than their absolute surface density. The study allowed the formulation of the general engineering principles for the selection of polymeric materials for the manufacturing of dynamic nanodevices using protein molecular motors.

Confinement of Water Droplets on Rectangular Micro/Nano-arrayed Surfaces

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“The digital age is dawning. The bio computer will make digital look like the abacus.“

Dan V. Nicolau Jr., Mercy Lard, Till Korten, Falco C. M. J. M. van Delft, Malin Persson, Elina Bengtsson, Alf Månsson, Stefan Diez, Heiner Linke and Dan V. Nicolau

Freely available online through the PNAS open access option

Abstract

The combinatorial nature of many important mathematical problems, including nondeterministic-polynomial-time (NP)-complete problems, places a severe limitation on the problem size that can be solved with conventional, sequentially operating electronic computers. There have been significant efforts in conceiving parallel-computation approaches in the past, for example: DNA computation, quantum computation, and microfluidics-based computation. However, these approaches have not proven, so far, to be scalable and practical from a fabrication and operational perspective. Here, we report the foundations of an alternative parallel-computation system in which a given combinatorial problem is encoded into a graphical, modular network that is embedded in a nanofabricated planar device. Exploring the network in a parallel fashion using a large number of independent, molecular-motor-propelled agents then solves the mathematical problem. This approach uses orders of magnitude less energy than conventional computers, thus addressing issues related to power consumption and heat dissipation. We provide a proof-of-concept demonstration of such a device by solving, in a parallel fashion, the small instance {2, 5, 9} of the subset sum problem, which is a benchmark NP-complete problem. Finally, we discuss the technical advances necessary to make our system scalable with presently available technology.

Actin filaments exploring the {2, 5, 9} device. The movie shows a time lapse of 200 typical fluorescence micrographs of actin filaments (shown in white) moving through a network (shown in blue) encoding the SSP with the set {2, 5, 9}. Exits labeled with green numbers represent correct results, and magenta numbers represent incorrect results. Below each exit, the number of actin that has arrived there is shown in white. The image of the network was obtained from an optical micrograph of the device and cropped to fit to the fluorescence image. Blurred objects passing over the network are actin filaments floating by in the solution. A background subtraction and contrast enhancement was performed evenly across the images with the use of ImageJ (imagej.nih.gov/ij/).

Discovery opens doors to creation of biological supercomputers that are about the size of a book

By Katherine Gombay Published: Feb 26 2016

McGill researchers take first steps towards bio-computer

 By TERRY DAWES, Cantech Letter Posted: February 26, 2016

Biological supercomputer model could change how we solve complex problems

Protein-powered chip makes biocomputer extremely energy efficient

By Sheena Goodyear, CBC News Posted: Feb 26, 2016

Biological systems can explore every possible solution rapidly.

by John Timmer – Feb 25, 2016 3:40pm EST