Biomedical Engineering Reference
In-Depth Information
8.5 Insect Research
he idea that microsystems, due to their small size and low weight, can be applied to monitor
and control the behavior of individual insects has recently attracted great interest from several
research groups. Nigel Franks, a behavioral ecologist at the University of Bristol in England,
glued small RF identiication tags to the backs of individual ants to track, register, and analyze
what the ants were doing using a computer. (Note that the FDA has approved—not without
controversy—a human-implantable RF identiication tag for subcutaneous use, the VeriChip, to
help track patients in acute care.) In principle, an insect could carry optical and chemical sen-
sors and be remotely directed to inaccessible or hazardous locations (e.g., chemical spill sites,
stealthy reconnaissance, etc.).
he large lying moth
Manduca sexta
is a widely used model because big loads (~1 g, about
half their body mass) do not signiicantly afect its light patterns. In 2008, David Erickson's
group at Cornell University (New York) implanted a microluidic device into the thorax of
M.
sexta
pupae to deliver reversibly paralyzing agents (such as l-glutamic acid, l-aspartic acid,
or γ-aminobutyric acid, which are also excitatory neurotransmitters at insect skeletal neuro-
muscular junctions but at high concentrations they are venoms produced by many spiders and
wasps). he device was implanted at the pupal stage (
Figure 8.19a
and
b
) because the wound
heals better—and presumably is integrated more harmonically with the physiology of the ani-
mal—at this developmental stage than at the adult stage. Once the device reached the adult stage
Eggs
Larva
(1st to 5th instar)
Pupa
Implantation
I-MAV
a
Days
0
15~18
21~23
40~44
42~46
b
c
1 cm
1 cm
Electroactive microwell drug delivery system
d
Dimensions
:
Electrochemically
dissolve
membrane to
release
L
-
glutamic acid
e
Polyimide
Membrane
Wing motion decreases
4 × 22 × 2.5 mm
Silicon
Weight
:
250 mg
Reservoir
Pyrex
1 mm
Bottom
electrode
Parylene
deposited
PDMS
FIGURE 8.19
Microluidic.control.of.insect.metabolism..(From.Aram.J..Chung.and.David.Erickson,.
“Engineering.insect.light.metabolics.using.immature.stage.implanted.microluidics,”.
Lab Chip
,.9,.
669-676,.2009..Reproduced.with.permission.from.The.Royal.Society.of.Chemistry.)
