Micromachines

24 pages, 4447 KB

Open AccessReview

Recent Trends on Micro/Nanofluidic Single Cell Electroporation

by Tuhin Subhra Santra and Fang Gang Tseng

Micromachines 2013, 4(3), 333-356; https://doi.org/10.3390/mi4030333 - 6 Sep 2013

Cited by 60 | Viewed by 18467

The behaviors of cell to cell or cell to environment with their organelles and their intracellular physical or biochemical effects are still not fully understood. Analyzing millions of cells together cannot provide detailed information, such as cell proliferation, differentiation or different responses to external stimuli and intracellular reaction. Thus, single cell level research is becoming a pioneering research area that unveils the interaction details in high temporal and spatial resolution among cells. To analyze the cellular function, single cell electroporation can be conducted by employing a miniaturized device, whose dimension should be similar to that of a single cell. Micro/nanofluidic devices can fulfill this requirement for single cell electroporation. This device is not only useful for cell lysis, cell to cell fusion or separation, insertion of drug, DNA and antibodies inside single cell, but also it can control biochemical, electrical and mechanical parameters using electroporation technique. This device provides better performance such as high transfection efficiency, high cell viability, lower Joule heating effect, less sample contamination, lower toxicity during electroporation experiment when compared to bulk electroporation process. In addition, single organelles within a cell can be analyzed selectively by reducing the electrode size and gap at nanoscale level. This advanced technique can deliver (in/out) biomolecules precisely through a small membrane area (micro to nanoscale area) of the single cell, known as localized single cell membrane electroporation (LSCMEP). These articles emphasize the recent progress in micro/nanofluidic single cell electroporation, which is potentially beneficial for high-efficient therapeutic and delivery applications or understanding cell to cell interaction. Full article

(This article belongs to the Special Issue Micro/Nanofluidic Devices for Single Cell Analysis)

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12 pages, 733 KB

Open AccessArticle

Lysis of a Single Cyanobacterium for Whole Genome Amplification

by Eric W. Hall, Samuel Kim, Visham Appadoo and Richard N. Zare

Micromachines 2013, 4(3), 321-332; https://doi.org/10.3390/mi4030321 - 21 Aug 2013

Cited by 11 | Viewed by 9441

Abstract

Bacterial species from natural environments, exhibiting a great degree of genetic diversity that has yet to be characterized, pose a specific challenge to whole genome amplification (WGA) from single cells. A major challenge is establishing an effective, compatible, and controlled lysis protocol. We present a novel lysis protocol that can be used to extract genomic information from a single cyanobacterium of Synechocystis sp. PCC 6803 known to have multilayer cell wall structures that resist conventional lysis methods. Simple but effective strategies for releasing genomic DNA from captured cells while retaining cellular identities for single-cell analysis are presented. Successful sequencing of genetic elements from single-cell amplicons prepared by multiple displacement amplification (MDA) is demonstrated for selected genes (15 loci nearly equally spaced throughout the main chromosome). Full article

(This article belongs to the Special Issue Micro/Nanofluidic Devices for Single Cell Analysis)

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15 pages, 434 KB

Open AccessArticle

Formation of Tunable, Emulsion Micro-Droplets Utilizing Flow-Focusing Channels and a Normally-Closed Micro-Valve

by Jung-Hao Wang and Gwo-Bin Lee

Micromachines 2013, 4(3), 306-320; https://doi.org/10.3390/mi4030306 - 17 Jul 2013

Cited by 12 | Viewed by 11024

Abstract

A mono-dispersed emulsion is of great significance in many chemical, biomedical and industrial applications. The current study reports a new microfluidic chip capable of forming tunable micro-droplets in liquids for emulsification applications. It can precisely generate size-tunable, uniform droplets using flow-focusing channels and a normally-closed valve, which is opened by a pneumatic suction force. Experimental data showed that micro-droplets with a diameter ranging from several to tens of micrometers could be precisely generated with a high uniformity. The droplet size is experimentally found to be dependent on the velocity of the dispersed-phase liquid, which is controlled by the deflection of the suction membrane. Emulsions with droplet sizes ranging from 5.5 to 55 μm are successfully observed. The variation in droplet sizes is from 3.8% to 2.5%. The micro-droplets have a uniform size and droplets smaller than those reported in previous studies are possible with this approach. This new microfluidic device can be promising for emulsification and other related applications. Full article

(This article belongs to the Collection Lab-on-a-Chip)

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20 pages, 1205 KB

Open AccessArticle

Approaches for a Fair Comparison and Benchmarking of Electromagnetic Vibration Energy Harvesters

by Clemens Cepnik and Ulrike Wallrabe

Micromachines 2013, 4(3), 286-305; https://doi.org/10.3390/mi4030286 - 5 Jul 2013

Cited by 6 | Viewed by 5523

Abstract

The performance of more than 60 different electromagnetic energy harvesters described in more than 100 publications is benchmarked. The benchmarking is based on earlier published parameters from literature as well as on two novel parameters introduced in this paper. The former allow to compare different harvester conversion principles as well as harvesters of different electrodynamic design principles. The latter consider the impact of ambient and boundary conditions for the most important sub-group, namely the resonant electrodynamic harvesters. The special consideration of how the mechanical damping and the energy conversion effectiveness depend on these conditions enables a fairer benchmarking of this common harvester type. High performing prototypes are identified, and the key parameters are provided for explanation. Finally, beneficial design approaches and the main challenges to maximize the output power are pointed out. Full article

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Micromachines, Volume 4, Issue 3 (September 2013) – 4 articles , Pages 286-356

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