Biomedical Engineering Reference
In-Depth Information
seen to elicit relative changes in insulin release. High levels of glucose in the
surrounding media produced higher levels of insulin release from the encapsulated
cells than low levels of glucose. A step increase from low to high concentration of
glucose causes increased release of insulin with a slight delay during which time it
is assumed the cells are adjusting insulin production and release to the change in
glucose levels (Fig.
12
).
6
Concluding Remarks
In the future, integration of smart capabilities into these devices could turn them
into complete biosensing and therapeutic platforms. Sensors to monitor cell via-
bility, glucose and insulin levels and controlled release of agents to promote angio-
genesis and biocompatibility or reduce fi brotic tissue formation around the implant
would improve the ability of the implant to interact with the body. Also, the ability
to transmit information outside the body so doctors can monitor the device would
be attractive additions.
It is clear that the engineering of viable, active tissues and organs requires control
over the environment in which the cells are going to be grown. Using techniques to
image, quantify and model the environment that cells are exposed to in vivo is lead-
ing researchers to engineer that environment using a variety of micro and nanofab-
rication techniques. Using microtechnology, control over surface structures provides
researchers with a means to systematically study how the scale and geometry of
various features affected cells seeded on them. As has been shown, precise engi-
neering of the microscale environment can create constructs that mimic native tis-
sues. The use of nanotechnology for tissue engineering is now going through the
initial stages where techniques are being refi ned and simplifi ed model-systems are
being used to gain insight into cellular responses to their nanoscale environment.
References
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basement membranes. Cells Tissues Organs 170:251-257.
Abrams GA, Goodman SL, Nealey PF, Franco M, Murphy CJ (2000a) Nanoscale topography of
the basement membrane underlying the corneal epithelium of the rhesus macaque. Cell Tissue
Res 299:39-46.
Abrams GA, Schaus SS, Goodman SL, Nealey PF, Murphy CJ (2000b) Nanoscale topography of
the corneal epithelial basement membrane and Descemet's membrane of the human. Cornea
19:57-64.
Abrams GA, Murphy CJ, Wang ZY, Nealey PF, Bjorling DE (2003) Ultrastructural basement
membrane topography of the bladder epithelium. Urol Res 31:341-346.
Alberts B, Bray D, Lewis J, Raff M, Roberts K, James DW (1994) Cell junctions, cell adhesions,
and the extracellular matrix. In: Molecular Biology of the Cell, pp 950-1006. New York:
Garland Publishing.
