抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Responsive polymer materials can adapt to surrounding environments, regulate transport of ions and molecules, change wettability and adhesion of different species on external stimuli, or convert chemical and biochemical signals into optical, electrical, thermal and mechanical signals, and vice versa. These materials are playing an increasingly important part in a diverse range of applications, such as drug delivery, diagnostics, tissue engineering and 'smart' optical systems, as well as biosensors, microelectromechanical systems, coatings and textiles. We review recent advances and challenges in the developments towards applications of stimuli-responsive polymeric materials that are self-assembled from nanostructured building blocks. We also provide a critical outline of emerging developments.

Emerging applications of stimuli-responsive polymer materials

Localized Surface Plasmon Resonance Sensors

Following Sharpless' visionary characterization of several idealized reactions as click reactions, the materials science and synthetic chemistry communities have pursued numerous routes toward the identification and implementation of these click reactions. Herein, we review the radical-mediated thiol-ene reaction as one such click reaction. This reaction has all the desirable features of a click reaction, being highly efficient, simple to execute with no side products and proceeding rapidly to high yield. Further, the thiol-ene reaction is most frequently photoinitiated, particularly for photopolymerizations resulting in highly uniform polymer networks, promoting unique capabilities related to spatial and temporal control of the click reaction. The reaction mechanism and its implementation in various synthetic methodologies, biofunctionalization, surface and polymer modification, and polymerization are all reviewed.

Thiol–Ene Click Chemistry

Surface plasmons (SPs) are coherent oscillations of conduction electrons on a metal surface excited by electromagnetic radiation at a metal -dielectric interface. The growing field of research on such light -metal interactions is known as ‘plasmonics’. 1-3 This branch of research has attracted much attention due to its potential applications in miniaturized optical devices, sensors, and photonic circuits as well as in medical diagnostics and therapeutics. 4-8

Nanostructured plasmonic sensors.

We developed a class of quasi-3D plasmonic crystal that consists of multilayered, regular arrays of subwavelength metal nanostructures. The complex, highly sensitive structure of the optical transmission spectra of these crystals makes them especially well suited for sensing applications. Coupled with quantitative electrodynamics modeling of their optical response, they enable full multiwavelength spectroscopic detection of molecular binding events with sensitivities that correspond to small fractions of a monolayer. The high degree of spatial uniformity of the crystals, formed by a soft nanoimprint technique, provides the ability to image binding events over large areas with micrometer spatial resolution. These features, together with compact form factors, low-cost fabrication procedures, simple readout apparatus, and ability for direct integration into microfluidic networks and arrays, suggest promise for these devices in label-free bioanalytical detection systems.

https://www.pnas.org/content/pnas/103/46/17143.full.pdf

Quantitative multispectral biosensing and 1D imaging using quasi-3D plasmonic crystals

This paper describes a new type of plasmonic sensor fabricated by imprint lithography using a soft, elastomeric mold. Angle-dependent, zero-order transmission experiments demonstrate the sensing potential of this device, which uses a two dimensional plasmonic crystal. Full angle-dependent mapping shows that the sensitivity to surface chemical binding events reaches maxima near regions of the plasmonic Brillouin zone where the dispersion curves of multiple surface plasmon polariton modes converge. This behavior, together with the simple, low cost procedures for building the structures, suggests a potentially important role for these devices in high performance chemical and biological sensing.

High performance plasmonic crystal sensor formed by soft nanoimprint lithography.

We describe in this report the preparation, structural characterization, and phase behaviors exhibited by supported metallic and bimetallic nanoparticles. Homometallic nanoparticles of either Pt or Ru were synthesized by the reduction of various precursors ((CH3)2Pt(COD), H2PtCl6, and RuCl3) onto different carbon supports:  Vulcan XC-72 (VXC) and Shawinigan Acetylene Black (SAB). The choice of precursor has a large structural influence on the reductive condensation of the Pt metal particles. All of the various precursors and supports produced particles with very similar size distributions, with the exception of (CH3)2Pt(COD), which formed a complex distribution of small (20 A) and large (>50 A) particles. The centerpiece of this study is the characterization of the growth behaviors seen in the synthesis of binary Pt−Ru nanoparticles. These heterometallic particles were synthesized via a seeded reductive condensation of one metal precursor onto pre-supported nanoparticles of a second metal; the latter serv...

The size-dependent structural phase behaviors of supported bimetallic (Pt-Ru) nanoparticles

The present invention provides plasmonic crystals comprising three-dimensional and quasi comprising three-dimensional distributions of metallic or semiconducting films, including multi-layered crystal structures comprising nanostructured films and film arrays. Plasmonic crystals of the present invention include precisely registered and deterministically selected nonplanar crystal geometries and spatial distributions providing highly coupled, localized plasmonic responses in thin film elements and/or nanostructures of the crystal. Coupling of plasmonic responses provided by three-dimensional and quasi-three dimensional plasmonic crystal geometries and structures of the present invention generates enhanced local plasmonic field distributions useful for detecting small changes in the composition of an external dielectric environment proximate to a sensing surface of the plasmonic crystal. Plasmonic crystal structures of the present invention are also useful for providing highly localized excitation and/or imaging of fluorophores proximate to the crystal surface.

Multispectral plasmonic crystal sensors

We describe a plasmonic crystal device possessing utility for optically transducing chemical forces. The device couples complex plasmonic fields to chemical changes via a chemoresponsive, surface-bound hydrogel. We find that this architecture significantly enhances the spectroscopic responses seen at visible wavelengths while enabling capacities for sensitive signal transduction, even in cases that involve essentially no change in refractive index, thus allowing analytical detection via colorimetric assays in both imaging and spectroscopic modes.

Nathan H. Mack

Papers

Quantitative multispectral biosensing and 1D imaging using quasi-3D plasmonic crystals

High performance plasmonic crystal sensor formed by soft nanoimprint lithography.

The size-dependent structural phase behaviors of supported bimetallic (Pt-Ru) nanoparticles

Multispectral plasmonic crystal sensors

Optical transduction of chemical forces