HETEROGENEOUS NANOSTRUCTURES FOR BIOMEDICAL DIAGNOSTICS - Bio-Inspired and Nanoscale Integrated Computing - page 435

Gold-coated Styrofoam ball

V

Plate
Electrode

R

z

b

θ

C x

V dc

Figure 16.6. A cross-section schematic of the device with the electrical connec-
tions. The capacitance C x between the top plate and the left electrode is a
function of dc voltage V dc applied to the electrode on the right. Angle of
rotation y of the top plate and the attractive electrostatic force is a function of
separation (z). The voltage V applied to the sphere is 289mV. The scheme is not
drawntoscale.

glued to a wire whose displacement was precisely controlled to separate less than
2 m from the plate. The Casimir effect produced a torque on the plate towards the
Styrofoam ball. As the distance between the plate and the electrodes beneath it
(increasing the distance to one of them, and decreasing it to the other) changes, the
capacitances between the electrodes and the plate would be altered. By measuring
the capacitance variations, the angular displacement of the plate was measured
(Fig. 16.6).
Chan et al. showed that the dependence of the rotation angle on the
separation between the surfaces is in agreement with calculations of the Casimir
force. This experiment demonstrated that quantum-electrodynamical effects play
a key role in MEMS and NEMS components when the separation between
components is in the nanometer range.

16.4. BIOMEDICAL-INSPIRED MICRO- AND NANOCOMPONENTS
FOR CARDIOVASCULAR MEDICINE

16.4.1. Integrating Micro- and Nanosensors:
Biomedical Implication
Recent advances in molecular biology and dramatic progress in micro- and
nanotechnology have occurred concomitantly. Development of specialized bio-
medical interfaces involves the exploration of biocompatible materials, ultra-
low-noise microelectronics to sense biological signals without disturbing or
interfering with the living tissue, as well as possible application of nanoscale
components such as carbon nano tubes (CNTs). It is anticipated that the
developed technologies in this field would be instrumental for a wide range of
implanted and portable analytic devices, such as DNA and protein sensors,
diagnostic micro Lab-on-a-Chip devices, and microelectronic interfaces for