Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 4

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
We present different processes used for the patterning and growth of stem cells based on microspotting, microcontact printing and 3D patterning. Microspotting and microcontact-printing technique have been performed to produce micropatterned surfaces for cell-biological applications. Biomolecules have been micropsotted and microstamped on plasma-polymerized poly ethylene glycol substrates. The patterns exhibited a firm stability and an improved feasibility for controlling cell localization, proliferation and even differentiation. Production and application of 3D substrate by combination of lithography and in situ UV cross linking of photoresist are also detailed. An application of these processes is the biofunctional surfaces were incubated with suspensions of human umbilical cord blood neural stem cells (HUCB-NSC). It was clearly observed how the cells adhered and grew in the protein patterned regions. After 4 weeks of culturing the cells were still anchored in the patterns. Immunocytochemistry studies indicate that cell differentiation can be controled by the combination of interface engineering and culture conditions.
Physical interactions of cells with the adhesive substrates of the microenvironment as well as the presence of the soluble growth factors are important for the proliferation capacity of neural stem cells. We have used biofunctionalized surface domains microcontact printed with either synthetic polyaminoacid poly-L-lysine or extracellular matrix (ECM) component such as fibronectin, to study the proliferation capacity of human umbilical cord blood-derived neural stem cells (HUCB- NSC). The proliferation measured by the expression of Ki-67 protein was accompanied by the investigation of the cell morphology under the transmission and scanning electron microscopy in different culture time, plating densities of cells and medium condition (serum-free or 2% of FBS). The poly-L-lysine domains of defined micro-scale area promoted the presence of round, loosely attached Ki-67-positive cells, while fibronectin domains of the same size allowed appearance of flattened, strongly attached cells with more differentiated phenotype. These results were in agreement with the non-specific, electrostatic type of interaction between cell and substrate on poly-L-lysine and integrin receptor-mediated specific adhesion on fibronectin. In this report we have described in vitro culture conditions, which allow for immobilization of the non- differentiated and highly proliferating population of neural stem/progenitor cells to the biofunctionalized surface. The microarrays with bioactive domains allocating non-differentiated and proliferating neural stem/progenitor cells may find application for drug and chemicals toxicology screening of diverse factors influencing neural development.
Bio-functionalized surfaces were prepared to study the adherence and differentiation capacity of neural stem cells derived from human umbilical cord blood (HUCB-NSC). Cell growth platforms containing arranged arrays of adhesive molecules were created by microcontact printing on a biologically inert surface. Biomolecules used to prepare microarray platforms included the extracellular matrix protein fibronectin and the polyaminoacid poly-L-lysine. HUCB-NSC plated on microplatforms at various serum conditions showed serum and molecule type dependent capacity for adhesion and differentiation. Poly-L-lysine allowed the maintenance of stem-like non differentiated cells attached to the surface, whereas fibronectin promoted spreading and neural commitment. Serum deprivation did not influence the attachment of HUCB-NSC to fibronectin, but significantly enhanced the attachment to poly-L-lysine and promoted dBcAMP induced neuronal differentiation. A bio-pattern of squares with interconnecting lines was used to guide neuronal differentiation by directing cell protrusion outgrowth. Tailoring the geometry of the bio-pattern enabled directing and monitoring of the neural stem cells development in the large scale multiparameter biotests.
Cell growth platforms with biofunctionalized surfaces were fabricated to control and direct HUCB-NSC fate decisions. Two different nano/micro techniques: microcontact printing and piezoelectric non-contact spotting were used to allocate biomolecules (poly-Llysine and fi bronectin) on cell-repellent, non adhesive substrate. Such methods allow controlling the spatial distribution and content of the biomolecules on the microarray and governing cell adhesion in unspecifi c (electrostatic) or specifi c (receptor-mediated) manner. Patterning of biomolecules in different conditions on the single growth platforms enables to infl uence and compare stem cells developmental processes (proliferation /differentiation) at variable environments. To refl ect/mimic stem cell niche we applied functional domains containing ECM protein spotted together with the small signaling molecules (notch, wnt, shh). Such approach enable directing of neural stem cell developmental program by inducing intracellular molecular pathways leading to either self renewing- or differentiating- (neuronal or astrocytic) state. We characterized active biofunctionalized domains on fabricated microarrays by applying two methods of surface analysis: ellipsometry measurement and surface plasmon resonance system. This type of bioengineered cell growth platforms can be used for screening the mechanisms governing neural stem cell fate decisions and adverse reactions upon environmental stimuli. Grant No 0141/B/ P01/2008/35.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.