LGC eBook - 2017 - 21

Accelerating Science Using Integrated PCR Tools * Point-of-Care Molecular Diagnostics Evolve

Isothermal microsystems can be designed for
simplicity and low-energy consumption and
therefore, proponents say, may outperform
PCR in portable, battery-operated detection
systems in the future, and in field conditions.
These methods include nucleic acid sequencebased amplification (NASBA), loop-mediated
isothermal amplification (LAMP), helicase
dependent amplification (HDA), rolling circle
amplification (RCA), and strand displacement
amplification (SDA).
Moving closer to true portability, but still in the
development stage, researchers at Michigan
State University reported the invention of an
inexpensive, user-friendly and compact device,
the Gene-Z, an isothermal genetic analysis
platform operated by an iPod Touch or Google's
Android tablets. Already validated for microbial
analysis in one application, the device could be
adapted, its developers say, to detecting cancer
in developing countries.
The system's features include isothermal

21

| GENengnews.com

amplification of DNA, RNA, and microRNAs,
10-30 minutes assay-time, and the potential for
GPS and networking of multiple devices. Unique
elements of the molecular approach include:
modifications of miRNAs to be able to amplify
and detect via LAMP, use of highly specific
genetic signatures extracted from a large number
of allelic sequences, and use of SYTO 82 dye to
track (LAMP using simple photodiodes).
Gene-Z developers say they expect that the
device will cost less than $1,000, with disposable
chips ranging from $2 to $20 based on the
density and application.
Convergent System
Supported by the Defense Advanced Research
Project Agency (DARPA's DxOD project) and the
Bill & Melinda Gates Foundation (Grand Challenges),
scientists in the departments of physics and bioengineering at University of California, Berkeley,
developed a microfluidic biomolecular amplification reader (µBAR): an inexpensive, handheld,

battery-powered instrument for pathogen
genotyping in the developing world. The device,
the scientists say, represents a convergence of
molecular biology, microfluidics, optics, and
electronics technology.
The device reportedly carries out isothermal
nucleic acid amplification assays with real-time
fluorescence readout at a fraction of the cost of
conventional benchtop thermocyclers. The
device also features cell phone data connectivity
and GPS sample geotagging, which can enable
epidemiological surveying and remote healthcare delivery.
The µBAR device controls assay temperature
through an integrated resistive heater and monitors
real-time fluorescence signals from 60 individual
reaction chambers using LEDs and phototransistors.
Assays are carried out on PDMS disposable
microfluidic cartridges which require no external
power for sample loading.
As a proof-of-principle, the authors, Frank Myers
http://www.GENengnews.com
LGC eBook - 2017

Table of Contents for the Digital Edition of LGC eBook - 2017
