3 research outputs found
On the Effect of Monomer Chemistry on Growth Mechanisms of Nonfouling PEG-like Plasma Polymers
It has been shown that both ions and neutral species
may contribute
to plasma polymer growth. However, the relative contribution from
these mechanisms remains unclear. We present data elucidating the
importance of considering monomer structure with respect to which
the growth mechanism dominates for nonfouling PEG-like plasma polymers.
The deposition rate for saturated monomers is directly linked with
ion flux to the substrate. For unsaturated monomers, the neutral flux
also plays a role, particularly at low power. Increased fragmentation
of the monomer at high power reduces the ability of unsaturated monomers
to grow via neutral grafting. Chemical characterization by X-ray photoelectron
spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry
(ToF-SIMS) confirm the role that plasma phase fragmentation plays
in determining the deposition rate and surface chemistry of the deposited
film. The simple experimental method used here may also be used to
determine which mechanisms dominate plasma deposition for other monomers.
This knowledge may enable significant improvement in future reactor
design and process control
Haptotatic Plasma Polymerized Surfaces for Rapid Tissue Regeneration and Wound Healing
Skin
has a remarkable capacity for regeneration; however, with an ever
aging population, there is a growing burden to the healthcare system
from chronic wounds. Novel therapies are required to address the problems
associated with nonhealing chronic wounds. Novel wound dressings that
can encourage increased reepithelialization could help to reduce the
burden of chronic wounds. A suite of chemically defined surfaces have
been produced using plasma polymerization, and the ability of these
surfaces to support the growth of primary human skin cells has been
assessed. Additionally, the ability of these surfaces to modulate
cell migration and morphology has also been investigated. Keratinocytes
and endothelial cells were extremely sensitive to surface chemistry
showing increased viability and migration with an increased number
of carboxylic acid functional groups. Fibroblasts proved to be more
tolerant to changes in surface chemistry; however, these cells migrated
fastest over amine-functionalized surfaces. The novel combination
of comprehensive chemical characterization coupled with the focus
on cell migration provides a unique insight into how a material’s
physicochemical properties affect cell migration
Development of Advanced Dressings for the Delivery of Progenitor Cells
Culture
surfaces that substantially reduce the degree of cell manipulation
in the delivery of cell sheets to patients are described. These surfaces
support the attachment, culture, and delivery of multipotent adult
progenitor cells (MAPC). It was essential that the processes of attachment/detachment
to the surface did not affect cell phenotype nor the function of the
cultured cells. Both acid-based and amine-based surface coatings were
generated from acrylic acid, propanoic acid, diaminopropane, and heptylamine
precursors, respectively. While both functional groups supported cell
attachment/detachment, amine coated surfaces gave optimal performance.
X-ray photoelectron spectroscopy (XPS) showed that at a primary amine
to carbon surface ratio of between 0.01 and 0.02, greater than 90%
of attached cells were effectively transferred to a model wound bed.
A dependence on primary amine concentration has not previously been
reported. After 48 h of culture on the optimized amine surface, PCR,
functional, and viability assays showed that MAPC retained their stem
cell phenotype, full metabolic activity, and biological function.
Consequently, in a proof of concept experiment, it was shown that
this amine surface when coated onto a surgical dressing provides an
effective and simple technology for the delivery of MAPC to murine
dorsal excisional wounds, with MAPC delivery verified histologically.
By optimizing for cell delivery using a combination of in vitro and
in vivo techniques, we developed an effective surface for the delivery
of MAPC in a clinically relevant format