Recent Developments in Artificial Molecular-Machine–Based Active Nanomaterials and Nanosystems

MRS Bulletin ◽  
2008 ◽  
Vol 33 (3) ◽  
pp. 226-231 ◽  
Author(s):  
Tony Jun Huang
Keyword(s):  
Single Molecule ◽  
Interdisciplinary Research ◽  
Recent Progress ◽  
High Strain ◽  
Molecular Machines ◽  
High Impact ◽  
Molecular Machine ◽  
Mechanical Motion ◽  
Structures And Properties ◽  
Recent Developments

AbstractArtificial molecular machines capable of converting chemical, electrochemical, and photochemical energy into mechanical motion represent a high-impact, fast-growing field of interdisciplinary research. These molecular-scale systems utilize a “bottom-up” technology centered upon the design and manipulation of molecular assemblies and are potentially capable of delivering efficient actuation at length scales dramatically smaller than traditional microscale actuators. As actuation materials, molecular machines have many advantages, such as high strain (40%–60%), high force and energy densities, and the capability to maintain their actuation properties from the level of a single molecule to the macroscale. These advantages have inspired researchers to develop molecular-machine–based active nanomaterials and nanosystems, including electroactive and photoactive polymers. This article will discuss the structures and properties of artificial molecular machines, as well as review recent progress on efforts to move molecular machines from solution to surfaces to devices.

scholarly journals Stochastically pumped adaptation and directional motion of molecular machines

2018 ◽  
Vol 115 (38) ◽  
pp. 9405-9413 ◽  
Author(s):  
R. Dean Astumian
Keyword(s):  
Single Molecule ◽  
Molecular Motors ◽  
High Efficiency ◽  
Probability Distributions ◽  
Molecular Machines ◽  
High Energy ◽  
Stochastic Thermodynamics ◽  
Recent Developments ◽  
Directional Motion ◽  
External Fluctuations

Recent developments in synthetic molecular motors and pumps have sprung from a remarkable confluence of experiment and theory. Synthetic accomplishments have facilitated the ability to design and create molecules, many of them featuring mechanically bonded components, to carry out specific functions in their environment—walking along a polymeric track, unidirectional circling of one ring about another, synthesizing stereoisomers according to an external protocol, or pumping rings onto a long rod-like molecule to form and maintain high-energy, complex, nonequilibrium structures from simpler antecedents. Progress in the theory of nanoscale stochastic thermodynamics, specifically the generalization and extension of the principle of microscopic reversibility to the single-molecule regime, has enhanced the understanding of the design requirements for achieving strong unidirectional motion and high efficiency of these synthetic molecular machines for harnessing energy from external fluctuations to carry out mechanical and/or chemical functions in their environment. A key insight is that the interaction between the fluctuations and the transition state energies plays a central role in determining the steady-state concentrations. Kinetic asymmetry, a requirement for stochastic adaptation, occurs when there is an imbalance in the effect of the fluctuations on the forward and reverse rate constants. Because of strong viscosity, the motions of the machine can be viewed as mechanical equilibrium processes where mechanical resonances are simply impossible but where the probability distributions for the state occupancies and trajectories are very different from those that would be expected at thermodynamic equilibrium.

scholarly journals A Review on Recent Progress of Glycan-Based Surfactant Micelles as Nanoreactor Systems for Chemical Synthesis Applications

2021 ◽  
Vol 2 (1) ◽  
pp. 168-186
Author(s):  
Bahareh Vafakish ◽  
Lee D. Wilson
Keyword(s):  
Chemical Synthesis ◽  
Chemical Reactions ◽  
Recent Progress ◽  
Chemical Species ◽  
Reaction Rates ◽  
Bulk Solution ◽  
Surfactant Micelles ◽  
Conventional Surfactant ◽  
Recent Developments ◽  
To Receive

The nanoreactor concept and its application as a modality to carry out chemical reactions in confined and compartmentalized structures continues to receive increasing attention. Micelle-based nanoreactors derived from various classes of surfactant demonstrate outstanding potential for chemical synthesis. Polysaccharide (glycan-based) surfactants are an emerging class of biodegradable, non-toxic, and sustainable alternatives over conventional surfactant systems. The unique structure of glycan-based surfactants and their micellar structures provide a nanoenvironment that differs from that of the bulk solution, and supported by chemical reactions with uniquely different reaction rates and mechanisms. In this review, the aggregation of glycan-based surfactants to afford micelles and their utility for the synthesis of selected classes of reactions by the nanoreactor technique is discussed. Glycan-based surfactants are ecofriendly and promising surfactants over conventional synthetic analogues. This contribution aims to highlight recent developments in the field of glycan-based surfactants that are relevant to nanoreactors, along with future opportunities for research. In turn, coverage of research for glycan-based surfactants in nanoreactor assemblies with tailored volume and functionality is anticipated to motivate advanced research for the synthesis of diverse chemical species.

Recent Developments in Social Policy in the New European Union

ILR Review ◽  
1994 ◽  
Vol 48 (1) ◽  
pp. 5-27 ◽  
Author(s):  
John T. Addison ◽  
W. Stanley Siebert
Keyword(s):  
European Union ◽  
Labor Market ◽  
Recent Progress ◽  
Adjustment Costs ◽  
Labor Policy ◽  
Market Regulation ◽  
The European Union ◽  
Recent Developments ◽  
Labor Market Regulation ◽  
Future Direction

This paper assesses the recent progress and future direction of labor policy in the European Community, now the European Union. The authors show that most of the mandates foreshadowed under the December 1989 Community Social Charter have now been enacted into law. They analyze the possible costs, as well as the benefits, of these firstphase mandates and show the link between these adjustment costs and the Community's policy of providing subsidies to its poorer member states. They also demonstrate how the new Treaty on European Union, agreed to at Maastricht in December 1991, has increased the scope for Community-level labor market regulation.

scholarly journals Rapid and multiplex preparation of engineered Mycobacterium smegmatis porin A (MspA) nanopores for single molecule sensing and sequencing

2021 ◽  
Author(s):  
Shuanghong Yan ◽  
Liying Wang ◽  
Xiaoyu Du ◽  
Shanyu Zhang ◽  
Sha Wang ◽  
...  
Keyword(s):  
Single Molecule ◽  
Mycobacterium Smegmatis ◽  
Recent Developments

Acknowledging its unique conical lumen structure, Mycobacterium smegmatis porin A (MspA) was the first type of nanopore that has successfully sequenced DNA. Recent developments of nanopore single molecule chemistry have...

scholarly journals Recent progress in single-molecule studies of mRNA localization in vivo

RNA Biology ◽  
2018 ◽  
Vol 16 (9) ◽  
pp. 1108-1118 ◽  
Author(s):  
Songhee H. Kim ◽  
Melissa Vieira ◽  
Jae Youn Shim ◽  
Hongyoung Choi ◽  
Hye Yoon Park
Keyword(s):  
Single Molecule ◽  
Recent Progress ◽  
Mrna Localization ◽  
Single Molecule Studies

Molecular Motors: Force and Movement Generated by Single Myosin II Molecules

Physiology ◽  
2002 ◽  
Vol 17 (5) ◽  
pp. 213-218 ◽  
Author(s):  
Caspar Rüegg ◽  
Claudia Veigel ◽  
Justin E. Molloy ◽  
Stephan Schmitz ◽  
John C. Sparrow ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Single Molecule ◽  
Molecular Motors ◽  
Molecular Motor ◽  
Myosin Ii ◽  
Force Production ◽  
Myosin Isoforms ◽  
Single Molecule Level ◽  
Recent Developments ◽  
Muscle Myosin

Muscle myosin II is an ATP-driven, actin-based molecular motor. Recent developments in optical tweezers technology have made it possible to study movement and force production on the single-molecule level and to find out how different myosin isoforms may have adapted to their specific physiological roles.

scholarly journals Human DNA2 possesses a cryptic DNA unwinding activity that functionally integrates with BLM or WRN helicases

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Cosimo Pinto ◽  
Kristina Kasaciunaite ◽  
Ralf Seidel ◽  
Petr Cejka
Keyword(s):  
Single Molecule ◽  
Nuclease Activity ◽  
Molecular Machine ◽  
Dna Unwinding ◽  
Metabolic Processes ◽  
Nuclease Domain

Human DNA2 (hDNA2) contains both a helicase and a nuclease domain within the same polypeptide. The nuclease of hDNA2 is involved in a variety of DNA metabolic processes. Little is known about the role of the hDNA2 helicase. Using bulk and single-molecule approaches, we show that hDNA2 is a processive helicase capable of unwinding kilobases of dsDNA in length. The nuclease activity prevents the engagement of the helicase by competing for the same substrate, hence prominent DNA unwinding by hDNA2 alone can only be observed using the nuclease-deficient variant. We show that the helicase of hDNA2 functionally integrates with BLM or WRN helicases to promote dsDNA degradation by forming a heterodimeric molecular machine. This collectively suggests that the hDNA2 motor promotes the enzyme's capacity to degrade dsDNA in conjunction with BLM or WRN and thus promote the repair of broken DNA.

scholarly journals Methods for protein delivery into cells: from current approaches to future perspectives

2020 ◽  
Vol 48 (2) ◽  
pp. 357-365
Author(s):  
Chalmers Chau ◽  
Paolo Actis ◽  
Eric Hewitt
Keyword(s):  
Single Molecule ◽  
Cell Biology ◽  
Protein Delivery ◽  
Mammalian Cells ◽  
Cultured Cells ◽  
Cellular Damage ◽  
Future Perspectives ◽  
Chemically Modified ◽  
Recent Developments ◽  
Direct Delivery

The manipulation of cultured mammalian cells by the delivery of exogenous macromolecules is one of the cornerstones of experimental cell biology. Although the transfection of cells with DNA expressions constructs that encode proteins is routine and simple to perform, the direct delivery of proteins into cells has many advantages. For example, proteins can be chemically modified, assembled into defined complexes and subject to biophysical analyses prior to their delivery into cells. Here, we review new approaches to the injection and electroporation of proteins into cultured cells. In particular, we focus on how recent developments in nanoscale injection probes and localized electroporation devices enable proteins to be delivered whilst minimizing cellular damage. Moreover, we discuss how nanopore sensing may ultimately enable the quantification of protein delivery at single-molecule resolution.

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