Biomedical Engineering Reference
In-Depth Information
human biosystem can be attained by characterizing the quantitative boundary conditions
of the human body and determining variation of those conditions with disease and envi-
ronmental change.
As a secondary consideration, the condition of this layer serves vital social and cultural
functions as it is a major determinant of our appearance and is thus of central interest to
the cosmetic industry. The multifaceted significance of SC necessitates a multidisciplinary
approach toward its analyses. Current researchers include dermatologists, cosmetic scien-
tists, physiologists, neonatologists, pharmaceutical scientists, and bioengineers.
10.4
System Architecture
The conceptual microsystem, proposed in Figure 10.1 involves the transfer of electrical or
physical (cellular/fluidic) entities. Currently accepted approaches to collect these samples
include disruption in skin structure through needle puncture, electroporation or vapor-
ization, or removal of SC through gels or tapes. Micromachined electrodes and needles
(microelectrodes or microneedles) can enable collection of the same information, with sig-
nificantly less trauma to the tissue, and have the potential of even eliminating it.
The microneedles and microelectrodes, when incorporated into the interface, will enable
the development of a generic front end to the microsystem. As illustrated in Figure 10.5,
such an interface can take care of most applications involving skin interaction, whether
diagnostic or therapeutic in nature. The rest of the system architecture would be highly
application specific thus obviating the need for a rigid architecture. The subsystems can be
broadly classified by the type of entity transferred: physical (fluid transfer) or electrical
(charge transfer), and the system may incorporate any or both types of interactions.
The interface system may be either a stand-alone diagnostic or therapeutic system, or
have both capabilities. An active feedback-controlled system in which the therapy
depends upon the diagnosis constitutes a “smart” system. The data collected may either
Bio-engineered skin interface
Interaction
Fluid transfer
Charge/Ionic transfer
Application
Diagnostic
Therapeutic
Reagent
analysis
Surface
probing
Drug
delivery
Employed in
Electrotherapy
Utilizes
Microneedles
Microelectrodes
FIGURE 10.5
Application tree of skin-interface system.
