Technology

AGILE robotic fish that look like

the real thing are being developed

to act as government spies.

The US Office of Naval Research

(ONR) in Alexandria, Virginia,

plans to fund the development of

“highly manoeuvrable artificial

fish for stealthy surveillance”,

according to a recent request for

research proposals . The fish would

likely use cameras to gather data –

on the features of a rogue ship’s

hull, say – and swim in shoals,

using sonar to share what they

find with one another. Although

robotic submarines are already

used to explore the ocean , the

stealth fish the ONR now wants

to develop will be smaller and

more agile .

The ONR is also interested in

civil applications for the fish,

which could act as an active lure

for sports fishing or as a robotic

companion for swimmers.

COATINGS that dissolve when

exposed to a voltage could be

used to release drugs implanted

in the body at specific times.

Researchers at the

Massachusetts Institute of

Technology alternately dipped

a glass substrate in a positively

charged anticoagulant drug and

a solution of negatively charged

nanoparticles to build up a series

50years ago on 7 February the US Advanced Research Projects Agency, now DARPA, was created in response to the USSR’s Sputnik launch

Bacteriophages, the viruses that prey on

bacteria and are notoriously picky about

which species they attack, are being put

to work in an electrical bacteria sensor.

Identifying bacteria is a critical

business for doctors and food safety

experts, but involves either culturing

the bacteria until there are enough to

look at them under a microscope or

amplifying their DNA. Both these

processes take hours, sometimes days.

Now Glenn Gulak and colleagues at

the University of Toronto, Canada, have

built a sensor that detects bacteria in

minutes. It consists of a positive and

a negative electrode separated by a

gap. Inside this “nanowell” is a small

amount of a bacteriophage specific to

a particular bacteria species.

When that bacteria is spotted onto

the well, the phage attacks, causing a

wave of dissolved metal ions to spill

out. The ions change the conductivity

of the well, allowing the bacteria to

be detected.

The approach was demonstrated by

researchers at Texas A&M University in

2005 using a large, expensive sensor.

Gulak’s sensor is 25 times smaller and

made from silicon, so it requires the

same fabrication technique as computer

chips and costs just 8 cents.

So far Gulak has only detected

two strains of E. coli. But the sensors

take up less than a square millimetre

each, so to identify unknown bacteria

hundreds could be integrated onto

a single chip with a different, picky

phage in each well.

The work was presented last week

at the International Solid State Circuits

Conference in San Francisco.

NAME THAT BACTERIA IN ONE

of alternating layers. Applying a

voltage caused the exposed

nanoparticle layer to dissolve,

releasing the drug. When the

voltage was switched off, the

layers stopped dissolving

(Proceedings of the National

Academy of Sciences, DOI:

10.1073/pnas.0706994105).

Such a device could be

implanted in a patient’s body

along with a battery. It could be

controlled remotely or it might

monitor the body and switch

itself on and off accordingly.

For better cellphone performance, get a landline. Currently, cellphone internet speeds

depend on the number of other people using the local base station. Now network

provider Telefónica O2 Europe has begun trials in the UK of a miniature base station it

calls a femtocell that users install at home. When anyone with a 3G phone is within

range, it intercepts those signals and sends them on via a fixed broadband line.

Machines have woken up to the smell of coffee. Instead of using thousands of

chemicals to predict a blend’s flavour, a device built by researchers at the Nestlé

Research Centre in Lausanne, Switzerland, focuses on the relative proportions of a

handful of chemicals. When scoring eight blends on tastes such as citrus and woody,

its judgement was similar to humans’ (Analytical Chemistry, DOI: 10.1021/ac702196z).

GIZMO

20% were asked for money

33% revealed where they live

4% met up with someone who lied about themselves

62% used their real name

0 10 20 30 40 50 60

BE MY VALENTINE VICTIM

UK internet daters’ actions and online

profiles have left them open to identity theft

and other scams

Nipon Das, a director at a biotechnology consulting firm in Manhattan, who tried unsuccessfully to delete his Facebook account last year. While the social

networking site offers users the option to deactivate their accounts, servers keep copies of the information indefinitely (The New York Times, 11 February)

“It’s like the Hotel California. You can never leave”

–No escape from the phages–

EYE

OF

SCIE

NCE

/SPL

SOU

RCE

: D

AR

PASO

UR

CE:

GET

SA

FE O

NLI

NE

Navy fishes for

intelligence

Drugs at the flick

of a switch

www.newscientist.com 16 February 2008 | NewScientist | 25

080216_N_Tech_Upfront.indd 25080216_N_Tech_Upfront.indd 25 11/2/08 18:07:5311/2/08 18:07:53