The results indicate that lowering pH down to pH 5.0 in wounds is counterproductive in aspect of keratinocyte function which is crucial for successful wound healing.

Spatial control of cell detachment is potentially of great interest when selecting cells for clonal expansion and in order to obtain a homogeneous starting population of cells aimed for tissue engineering purposes. Here, selective detachment and cell sorting of human primary keratinocytes and fi broblasts is achieved using thin fi lms of a conjugated polymer. Upon electrochemical oxidation, the polymer fi lm swells, cracks, and fi nally detaches taking cells cultured on top along with it. The polymer can be patterned using standard photolithography to fabricate a cross-point matrix with polymer pixels that can be individually addressed and thus detached. Detachment occurs above a well-defi ned threshold of +0.7 V versus Ag/AgCl, allowing the use of a relatively simple and easily manufactured passive matrix-addressing confi guration, based on a resistor network, to control the cell-sorting device.

The possibility to use a suspended tridimensional matrix as scaffolding for re-epithelialization of in vitro cutaneous wounds was investigated with the aid of a human in vitro wound healing model based on viable full thickness skin. Macroporous gelatin microcarriers, CultiSpher-S, were applied to in vitro wounds and cultured for 21 days. Tissue sections showed incorporation of wound edge keratinocytes into the microcarriers and thicker neoepidermis in wounds treated with microcarriers. Thickness of the neoepidermis was measured digitally, using immunohistochemical staining of keratins as epithelial demarcation. Air-lifting of wounds enhanced stratification in control wounds as well as wounds with CultiSpher-S. Immunohistochemical staining revealed expression of keratin 5, keratin 10, and laminin 5 in the neoepidermal component. We conclude that the CultiSpher-S microcarriers can function as tissue guiding scaffold for re-epithelialization of cutaneous wounds.

No abstract

Adherent cells cultured in vitro must usually, at some point, be detached from the culture substrate. Presently, the most common method of achieving detachment is through enzymatic treatment which breaks the adhesion points of the cells to the surface. This comes with the drawback of deteriorating the function and viability of the cells. Other methods that have previously been proposed include detachment of the cell substrate itself, which risks contaminating the cell sample, and changing the surface energy of the substrate through thermal changes, which yields low spatial resolution and risks damaging the cells if they are sensitive to temperature changes. Here cell culture substrates, based on thin films of the ferroelectric polyvinylidene fluoride trifluoroethylene (PVDF-TrFE) co-polymer, are developed for electroactive control of cell adhesion and enzyme-free detachment of cells. Fibroblasts cultured on the substrates are detached through changing the direction of polarization of the ferroelectric substrate. The method does not affect subsequent adhesion and viability of reseeded cells.