There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

Gold nanoparticles have been used in biomedical applications since their first colloidal syntheses more than three centuries ago. However, over the past two decades, their beautiful colors and unique electronic properties have also attracted tremendous attention due to their historical applications in art and ancient medicine and current applications in enhanced optoelectronics and photovoltaics. In spite of their modest alchemical beginnings, gold nanoparticles exhibit physical properties that are truly different from both small molecules and bulk materials, as well as from other nanoscale particles. Their unique combination of properties is just beginning to be fully realized in range of medical diagnostic and therapeutic applications. This critical review will provide insights into the design, synthesis, functionalization, and applications of these artificial molecules in biomedicine and discuss their tailored interactions with biological systems to achieve improved patient health. Further, we provide a survey of the rapidly expanding body of literature on this topic and argue that gold nanotechnology-enabled biomedicine is not simply an act of ‘gilding the (nanomedicinal) lily’, but that a new ‘Golden Age’ of biomedical nanotechnology is truly upon us. Moving forward, the most challenging nanoscience ahead of us will be to find new chemical and physical methods of functionalizing gold nanoparticles with compounds that can promote efficient binding, clearance, and biocompatibility and to assess their safety to other biological systems and their long-term term effects on human health and reproduction (472 references).

The golden age: gold nanoparticles for biomedicine

Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article.

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Present and Future of Surface-Enhanced Raman Scattering

The widespread presence of mycotoxins in nature not only poses a huge health risk to people in terms of food but also causes incalculable losses to the agricultural economy. As a rapidly developing technology in recent years, the mycotoxin immunoassay technology has approached or even surpassed the traditional chromatography technology in some aspects. Using this approach, the lateral flow immunoassay (LFIA) has attracted the interest of researchers due to its user-friendly operation, short time consumption, little interference, low cost, and ability to process a large number of samples at the same time. This paper provides an overview of the immunogens commonly used for mycotoxins, the development of antibodies, and the use of gold nanoparticles, quantum dots, carbon nanoparticles, enzymes, and fluorescent microsphere labeling materials for the construction of LFIAs to improve detection sensitivity. The analytical performance, detection substrates, detection limits or detection ranges of LFIA for mycotoxins have been listed in recent years. Finally, we describe the future outlook for the field, predicting that portable mobile detection devices and simultaneous quantitative detection of multiple mycotoxins is one of the important directions for future development.

Immunoassays for rapid mycotoxin detection: state of the art.

Lateral flow immunoassay for the simultaneous detection of fipronil and its metabolites in food samples.

In order to develop highly sensitive immunoassays for detecting the major peanut allergen, Ara h 2, we prepared six monoclonal antibodies (mAb) with high affinity to Ara h 2. Using mAb 5 as a capture antibody and HRP-labeled mAb 1 as a detection antibody, a sandwich enzyme-linked immunoassay (ELISA) was established with a limit of detection (LOD) of 0.02 ng/mL. An immunochromatographic strip based on these two mAbs was also established with a LOD of 1 ng/mL. Both tests showed high specificity in cross-reactivity experiments. Sample analyses indicated that these two immunoassays were feasible, accurate, and highly sensitive for measuring allergen Ara h 2 of food.

Development of Sandwich ELISA and Immunochromatographic Strip for the Detection of Peanut Allergen Ara h 2

Summary
An enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody was established to detect aflatoxin B1 (AFB1) in tea The antibody was prepared from a hybridoma derived by fusing Sp2/0-Ag14 myeloma cells and immunised spleen B cells The effects from pH, ionic strength, and organic solvents on immunoassay were optimised and the 50% inhibition (IC50) value was 0057 ± 0007 ng mL−1 Spiked black and green tea samples at 10, 20 and 50 ng g−1 levels of AFB1 were detected with this proposed ELISA The recoveries for black tea samples ranged from 685% to 1177% and 735 to 1143% for green tea samples This immunoassay showed no cross-reactions with other mycotoxin family but good recognition with related aflatoxins These results indicate that the ELISA assay could be used as a screening method for aflatoxin detection in tea samples

Detection of aflatoxins in tea samples based on a class‐specific monoclonal antibody

SERS-active silver nanoparticle trimers were assembled in this study for the first time, through the aptamer of a cancer biomarker, alpha fetoprotein (AFP). It was successfully used for the sub-attomolar detection of AFP, with a limit of detection as low as 0.097 aM, which is the lowest reported so far.

Chuanlai Xu

Papers

Immunoassays for rapid mycotoxin detection: state of the art.

Lateral flow immunoassay for the simultaneous detection of fipronil and its metabolites in food samples.

Development of Sandwich ELISA and Immunochromatographic Strip for the Detection of Peanut Allergen Ara h 2

Detection of aflatoxins in tea samples based on a class‐specific monoclonal antibody

SERS-active silver nanoparticle trimers for sub-attomolar detection of alpha fetoprotein