Biodegradable Elastomeric Polymers and MEMS in Tissue Engineering 55
3.4 MEMS PRINCIPLES IN TISSUE ENGINEERING
In the past decade, microscale technologies have emerged as a powerful tool for
biological and biomedical applications.
MEMS research and development has
remained intense to solve complex problems at the cellular and molecular level.
Biological or Biomedical MEMS, BioMEMS, can be deﬁned as the application
of micro– and nanotechnology to develop devices or systems that are used for
the processing, delivery, manipulation, analysis, or construction of biological
and chemical modalities.
The advancement of BioMEMS technologies has pro-
gressed, and will have a broad and signiﬁcant impact in the ﬁelds of biology and
medicine if fully realized.
Few other engineering techniques are able to closely match the micro to
millimeter size dimension of tissues in the human body with the precision and
accuracy of BioMEMS techniques.
Due to these advantages, BioMEMS holds
great promise in addressing the challenges found in many disciplines such as di-
agnostic, therapeutic, sensing, detection, and tissue engineering applications.
The potential to mimic complex tissue architecture and in vivo conditions makes
BioMEMS a powerful tool for tissue engineering.
3.5 MEMS APPLICATIONS IN TISSUE ENGINEERING
Although BioMEMS based tissue engineering is a rapidly advancing ﬁeld, research
involving the use of biodegradable elastomers coupled with microfabrication
processes is new and fairly limited. Discussed in the following section are
BioMEMS based techniques involving hydrogels and biodegradable elastomers to
construct 3D structures, control cell adhesion, control cell morphology, and create
microvasculature for 3D constructs.
The recent progress of MEMS based technologies has lead to new approaches
to study in vitro cell culture environments. Many of these new techniques utilize
a soft lithography approach to rapidly produce 3D microstructures. Leclerc
et al. used a photosensitive caprolactone and lactide based polymer to fabricate
biodegradable polymer microstructures down to 50 μm for tissue engineered liver
As seen in Fig. 3.7, Leclerc et al. successfully created various single and
multistepwise microstructures using a soft lithographic technique. In addition,
the single stepwise microstructures supported the attachment, spreading, and
growth of a variety of mammalian cell types. Other groups have also successfully
created complex 3D polymer constructs for hepatic tissue engineering. In 2007,
Tsang et al. created PEGDA hydrogel constructs for hepatic cell encapsulation.
By combining a PEG based hydrogel with a multilayer fabrication method, Tsang
and co-workers were able to fabricate highly cell–encapsulated scaffolds with
architecture to facilitate nutrient delivery through convective ﬂow.
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