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

Droplet microfluidics generates and manipulates discrete droplets through immiscible multiphase flows inside microchannels Due to its remarkable advantages, droplet microfluidics bears significant value in an extremely wide range of area In this review, we provide a comprehensive and in-depth insight into droplet microfluidics, covering fundamental research from microfluidic chip fabrication and droplet generation to the applications of droplets in bio(chemical) analysis and materials generation The purpose of this review is to convey the fundamentals of droplet microfluidics, a critical analysis on its current status and challenges, and opinions on its future development We believe this review will promote communications among biology, chemistry, physics, and materials science

Emerging Droplet Microfluidics

Microdroplets in microfluidics offer a great number of opportunities in chemical and biological research. They provide a compartment in which species or reactions can be isolated, they are monodisperse and therefore suitable for quantitative studies, they offer the possibility to work with extremely small volumes, single cells, or single molecules, and are suitable for high-throughput experiments. The aim of this Review is to show the importance of these features in enabling new experiments in biology and chemistry. The recent advances in device fabrication are highlighted as are the remaining technological challenges. Examples are presented to show how compartmentalization, monodispersity, single-molecule sensitivity, and high throughput have been exploited in experiments that would have been extremely difficult outside the microfluidics platform.

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Microdroplets in microfluidics: an evolving platform for discoveries in chemistry and biology

This critical review discusses the current understanding of the formation, transport, and merging of drops in microfluidics. We focus on the physical ingredients which determine the flow of drops in microchannels and recall classical results of fluid dynamics which help explain the observed behaviour. We begin by introducing the main physical ingredients that differentiate droplet microfluidics from single-phase microfluidics, namely the modifications to the flow and pressure fields that are introduced by the presence of interfacial tension. Then three practical aspects are studied in detail: (i) The formation of drops and the dominant interactions depending on the geometry in which they are formed. (ii) The transport of drops, namely the evaluation of drop velocity, the pressure-velocity relationships, and the flow field induced by the presence of the drop. (iii) The fusion of two drops, including different methods of bridging the liquid film between them which enables their merging.

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Dynamics of microfluidic droplets.

This article reviews the application of electric circuit methods for the analysis of pressure-driven microfluidic networks with an emphasis on concentration- and flow-dependent systems. The application of circuit methods to microfluidics is based on the analogous behaviour of hydraulic and electric circuits with correlations of pressure to voltage, volumetric flow rate to current, and hydraulic to electric resistance. Circuit analysis enables rapid predictions of pressure-driven laminar flow in microchannels and is very useful for designing complex microfluidic networks in advance of fabrication. This article provides a comprehensive overview of the physics of pressure-driven laminar flow, the formal analogy between electric and hydraulic circuits, applications of circuit theory to microfluidic network-based devices, recent development and applications of concentration- and flow-dependent microfluidic networks, and promising future applications. The lab-on-a-chip (LOC) and microfluidics community will gain insightful ideas and practical design strategies for developing unique microfluidic network-based devices to address a broad range of biological, chemical, pharmaceutical, and other scientific and technical challenges.

Design of pressure-driven microfluidic networks using electric circuit analogy

We describe the design, fabrication and use of a single-layered poly(dimethylsiloxane) microfluidic structure for the entrapment and release of microdroplets in an array format controlled entirely by liquid flow. Aqueous picoliter droplets are trapped en masse and optically monitored for extended periods of time. Such an array-based approach is used to characterize droplet shrinkage, aggregation of encapsulated E. colicells and enzymatic reactions. We also demonstrate that trapped droplets may be recovered from the microfluidic array for further processing.

Static microdroplet arrays: a microfluidic device for droplet trapping, incubation and release for enzymatic and cell-based assays

Here we present the design, fabrication and operation of a microfluidic device to trap droplets in a large array of droplet pairs in a controlled manner with the aim of studying the transport of small molecules across the resultant surfactant bilayers formed between the droplet pairs.

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Dan Bratton

Papers

Static microdroplet arrays: a microfluidic device for droplet trapping, incubation and release for enzymatic and cell-based assays

A double droplet trap system for studying mass transport across a droplet-droplet interface