Compactness Determines the Success of Cube and Octahedron Self-Assembly

Azam, Anum; Leong, Timothy G.; Zarafshar, Aasiyeh M.; Gracias, David H.

doi:10.1371/journal.pone.0004451

Cited by 38 publications

(32 citation statements)

References 19 publications

(22 reference statements)

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“…However, suspected decreased susceptibility of ACT or, at least, longer parasite clearance times have been described in Cambodia [11-14]. In addition, prior therapy by amodiaquine-containing ACT selected reduced response to monodesethylamodiaquine, suggested that amodiaquine-containing regimens may rapidly lose efficacy in Africa [15].…”

Section: Introductionmentioning

confidence: 99%

Ex vivo activity of the ACT new components pyronaridine and piperaquine in comparison with conventional ACT drugs against isolates of Plasmodium falciparum

Pascual¹,

Parola

Benoit‐Vical

et al. 2012

Malar J

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BackgroundThe aim of the present work was to assess i) ex vivo activity of pyronaridine (PND) and piperaquine (PPQ), as new components of artemisinin-based combination therapy (ACT), to define susceptibility baseline, ii) their activities compared to other partner drugs, namely monodesethylamodiaquine (MDAQ), lumefantrine (LMF), mefloquine (MQ), artesunate (AS) and dihydroartemisinin (DHA) against 181 Plasmodium falciparum isolates from African countries, India and Thailand, and iii) in vitro cross-resistance with other quinoline drugs, chloroquine (CQ) or quinine (QN).MethodsThe susceptibility of the 181 P. falciparum isolates to the nine anti-malarial drugs was assessed using the standard 42-hours 3H-hypoxanthine uptake inhibition method.ResultsThe IC50 values for PND ranged from 0.55 to 80.0 nM (geometric mean = 19.9 nM) and from 11.8 to 217.3 nM for PPQ (geometric mean = 66.8 nM). A significant positive correlation was shown between responses to PPQ and PND responses (rho = 0.46) and between PPQ and MDAQ (rho = 0.30). No significant correlation was shown between PPQ IC50 and responses to other anti-malarial drugs. A significant positive correlation was shown between responses to PND and MDAQ (rho = 0.37), PND and LMF (rho = 0.28), PND and QN (rho = 0.24), PND and AS (rho = 0.19), PND and DHA (rho = 0.18) and PND and CQ (rho = 0.16). All these coefficients of correlation are too low to suggest cross-resistance between PPQ or PND and the other drugs.ConclusionsIn this study, the excellent anti-malarial activity of PPQ and PND was confirmed. The absence of cross-resistance with quinolines and artemisinin derivatives is consistent with the efficacy of the combinations of PPQ and DHA or PND and AS in areas where parasites are resistant to conventional anti-malarial drugs.

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Section: Introductionmentioning

confidence: 99%

Ex vivo activity of the ACT new components pyronaridine and piperaquine in comparison with conventional ACT drugs against isolates of Plasmodium falciparum

Pascual¹,

Parola

Benoit‐Vical

et al. 2012

Malar J

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“…For example, a cruciform was almost always chosen to self-fold a cube. However, a recent study of the self-folding of all 11 nets for the cube and octahedron revealed that different nets fold through different pathways and have different yield (29). In particular, it was found that compact nets had higher yield.…”

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confidence: 99%

Algorithmic design of self-folding polyhedra

Pandey

Ewing

Kunas

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

105

129

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Self-assembly has emerged as a paradigm for highly parallel fabrication of complex three-dimensional structures. However, there are few principles that guide a priori design, yield, and defect tolerance of self-assembling structures. We examine with experiment and theory the geometric principles that underlie self-folding of submillimeter-scale higher polyhedra from two-dimensional nets. In particular, we computationally search for nets within a large set of possibilities and then test these nets experimentally. Our main findings are that (i) compactness is a simple and effective design principle for maximizing the yield of self-folding polyhedra; and (ii) shortest paths from 2D nets to 3D polyhedra in the configuration space are important for rationalizing experimentally observed folding pathways. Our work provides a model problem amenable to experimental and theoretical analysis of design principles and pathways in self-assembly.microfabrication | origami | programmable matter | viral capsid N ature uses hierarchical assembly to construct essential biomolecules such as proteins and nucleic acids and biological containers such as viral capsids. Our increased understanding of biological systems has inspired several synthetic methods of selfassembly (1). Conversely, part of the promise of synthetic selfassembly has been that it may yield essential insights into the formation of biological structure. In order to realize these ambitions, it is necessary to develop model experimental systems and theoretical analyses that make precise the analogies between natural and synthetic self-assembly. Abstraction of the essentials of complex biochemical processes is an important step in this process, and perhaps the simplest abstraction is of the geometric form of a biological structure. Two such abstractions are the CasparKlug (CK) theory of viral structure (2) and hydrophobic-polar (HP) lattice models for protein folding (3). The consequences of geometry alone can be striking in such models: The CK theory provides a valuable classification of virus shapes by T number, and much of the detailed architecture of compact proteins such as helices, and antiparallel and parallel sheets emerges from purely steric restrictions on long chain molecules (4). Building such geometric models is, of course, part of a long tradition in biochemistry. What is now striking is the ability to build basic geometric structures such as polyhedra in laboratory self-assembly experiments using molecules such as DNA (5-8) or 100-nm to 1-mm scale lithographically interconnected panels (9). In addition to the intellectual value of such experiments, many of the self-assembled structures realized cannot be fabricated by alternate methods, and they are of technological relevance in optics, electronics, and medicine. In order to translate these self-assembly processes from the laboratory to a manufacturing setting, there is a need to uncover rules that govern yield and defect tolerance. Several experiments, in combination with a growing body of theory, point ...

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“…Given these considerations, four truncated faces with a metal pad thickness of 4.9 lm and a gap spacing of 7.5 lm were used to obtain 3D structures on an underlying conducting channel. Other researchers investigating the self-folding process for complex structures, such as dodecahedra, icosahedra, and truncated octahedra, found compactness in the 2D pattern to heavily influence folding yields 41 and can be used as a design criterion. 42 Another interesting investigation describes the hierarchy of assembly steps to form microcontainers.…”

Section: Methodsmentioning

confidence: 99%