Biomedical Engineering Reference
In-Depth Information
32.
Tissue Eng
. 2007 Dec;
13(12):3003-10. Bioreactor for
application of subatmospheric
pressure to three-dimensional
cell culture. Wilkes RP, McNulty
AK, Feeley TD, Schmidt MA,
Kieswetter K. Kinetic Concepts
Inc., San Antonio, Texas 78249.
Vacuum-assisted closure (VAC) negative pressure
wound therapy (NPWT) is a highly successful and
widely used treatment modality for wound healing,
although no apparatus exists to monitor the effects of
subatmospheric pressure application in vitro. Such
an apparatus is desirable to better understand the
biological effects of this therapy and potentially
improve upon them. This article describes the
development and validation of a novel bioreactor
that permits such study. Tissue analogues consisting
of 3-dimensional fibroblast-containing fibrin clots
were cultured in off-the-shelf disposable cell culture
inserts and multiwell plates that were integrated into
the bioreactor module. Negative pressure dressings,
commercialized for wound therapy, were placed on
top of the culture, and subatmospheric pressure was
applied to the dressing. Cultures were perfused with
media at controlled physiologic wound exudate flow
rates. The design of this bioreactor permits
observation of the culture using an inverted
microscope in brightfield and fluorescence modes
and sustained incubation of the system in a 5%
carbon dioxide atmosphere. This closed-system
mimics the wound microenvironment under VAC
NPWT. Matrix compression occurs as the
subatmospheric pressure draws the dressing material
down. At the contact zone, surface undulations were
clearly evident on the fibroblast-containing tissue
analogues at 24 h and appeared to correspond to the
dressing microstructure. The bioreactor design,
consisting of sterilizable machined plastics and
disposable labware, can be easily scaled to multiple
units. Validation experiments show that cell survival
in this system is comparable with that seen in cells
grown in static tissue culture. After application of
VAC NPWT, cell morphology changed, with cells
appearing thicker and with an organized actin
cytoskeleton. The development and validation of this
new culture system establishes a stable platform for
in vitro investigations of subatmospheric pressure
application to tissues.
