In Situ Study of the Thermoresponsive Behavior of Micropatterned Hydrogel Films by Imaging Ellipsometry

Schmaljohann, Dirk; Nitschke, Mirko; Schulze, R.; Eing, Andreas; Werner, Carsten; Eichhorn, Klaus‐Jochen

doi:10.1021/la0476128

Cited by 53 publications

(52 citation statements)

References 43 publications

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“…A TEM grid is used as mask to give a proof-of-principle for the lithographic process [60]. The resolution is 60 µm, however, other masks are expected to give much higher resolution.…”

Section: Photolithographic Patterning Of the Thermo-responsive Hydrogelsmentioning

confidence: 99%

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Thermo-responsive polymers and hydrogels in tissue engineering

Schmaljohann

2005

E-Polymers

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Various aspects of synthetic polymers and hydrogels in tissue engineering are discussed. A series of graft copolymers based on either N-isopropylacrylamide or N,N-diethylacrylamide as polymer backbone, and on poly(ethylene glycol) as side chain were prepared and characterized. These polymers were then used for the preparation of surface-immobilized hydrogels. The thermo-responsive behaviour was studied on model substrates by ellipsometry. The use of thermoresponsive polymers for in vitro studies allows the control of surface properties and thus the stimulation of cell adhesion and detachment through temperature changes. The cellular response was investigated by cultivation of mouse fibroblasts on surface-immobilized, thermo-responsive hydrogels. It was demonstrated that mouse fibroblasts adhere and detach as a function of the temperature, which then could be related to the change in surface properties. The concept is finally extended to the preparation of patterned hydrogels, which were studied by imaging ellipsometry.

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“…A TEM grid is used as mask to give a proof-of-principle for the lithographic process [60]. The resolution is 60 µm, however, other masks are expected to give much higher resolution.…”

Section: Photolithographic Patterning Of the Thermo-responsive Hydrogelsmentioning

confidence: 99%

“…10. The height of hydrogel film can be followed through the ∆ profile, because ∆ goes along with the film thickness [34,60]. It is noteworthy that the resolution is maintained after swelling in DI water.…”

Section: Photolithographic Patterning Of the Thermo-responsive Hydrogelsmentioning

confidence: 99%

Thermo-responsive polymers and hydrogels in tissue engineering

Schmaljohann

2005

E-Polymers

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“…Polymer networks being capable of stimuli responsive volume changing and controllable mass transferring have been increasingly recognized as building blocks in microfluidic devices (sensors, actuators, fluid pumps, and valves) [67], scaffolds in tissue engineering and regenerative medicine [68][69][70], actuators in artificial muscle development [63][64][65], and targeted and controlled release elements in drug delivery systems [17], including iontophoresis [71]. Hydrogels are flexible and fragile and require mechanical support.…”

Section: Supported Hydrogel Filmsmentioning

confidence: 99%

Hydrogel Films on Optical Fiber Core: Properties, Challenges, and Prospects for Future Applications

Казаков¹

2012

New Polymers for Special Applications

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There are experimental evidences [29][30][31] of de-swelling effects of different monovalent (Li + , Na + , K + , Cs + ) and divalent (Ca 2+ , Mg 2+ , Sr 2+ , Ba 2 ) ions in hydrogels of different chemical nature, including the biologically relevant gels [32] and cross-linked DNA [33]. Interestingly, at the same molar ratios of divalent to monovalent cations, ~ 1 mM to 30 mM, respectively, similar volume changes were observed in biological polyelectrolyte systems during physiological processes like nerve excitation, musle contraction, and cell locomotion [34][35][36][37][38][39][40].Surfactants. The extensive theoretical [41][42][43] and experimental [44][45][46][47][48] studies have shown that addition of anionic, cationic, and nonionic surfactants to the solution containing a gel can also influence the volume phase transition temperature and swelling degree of hydrogels depending on their hydrophobicity and charge of the polymer network. In general, addition of anionic or cationic surfactant to the solution of nonionic hydrogel rises the transition temperature as well as the swelling range, whereas the nonionic surfactant does not affect the transition temperature or the volume change. The surfactants with ionic head groups convert the neutral hydrogels to a polyelectrolyte gels when bind to the nonionic polymer networks, so that the transition temperatures elevate due to introduction of additional osmotic pressure by ionization. The changes in the volume phase transition are also dependent on the length of hydrophobic tail of ionic surfactants and the critical concentration of micelle formation. Indeed, it was found [45] that the transition temperature of nonionic poly(acryloyl-L-proline methyl ester) hydrogels increases more drastically in solutions of anionic sodium alkane sulfonate surfactants with the higher number of methylene units in the tail and at lower concentration than those with the shorter tails. The other interesting findings are [47]: (i) the amount of an ionic surfactant bound onto the swollen network of the nonionic PNIPA hydrogel is much greater than that to the collapsed

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“…To fabricate thermo-responsive cell culture carriers with lateral microstructures, the masking technique described in detail in [29] was used. Briefly, argon plasma treatment of a spin-coated poly(NiPAAmco-DEGMA) film was performed as described above with the sample covered by a transmission electron microscopy grid.…”

Section: Plasma Immobilizationmentioning

confidence: 99%

“…Accordingly, the allocation of fibronectin as a major component of the ECM was investigated by immunofluorescence. For that purpose a substrate with lateral structures in the order of several 100 µm (i. e. well above the dimension of a single cell) of poly(NiPAAm-co-DEGMA) was employed [29]. This allows a direct comparison of the cell behaviour on adhesive uncoated areas with thermoresponsive areas in the same image ( Figure 5).…”

Section: Protein Staining Experimentsmentioning

confidence: 99%

Detachment of human endothelial cell sheets from thermo-responsive poly(NiPAAm-co-DEGMA) carriers

Nitschke¹,

Goetze²,

Gramm³

et al. 2007

Express Polym. Lett.

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Abstract.The technique of gently harvesting cells and cell sheets using stimuli-responsive cell culture carriers was applied to human umbilical vein cord endothelial cells (HUVEC). To meet the particular requirements of this demanding cell type, a copolymer consisting of N-isopropylacrylamide and diethyleneglycol methacrylate (poly(NiPAAm-co-DEGMA)) was combined with a fine-tuned protein pre-coating. Using this approach the detachment of HUVEC sheets was studied. Furthermore, the behavior of the extracellular matrix upon cell detachment was followed by protein staining. The results demonstrate the feasibility of harvesting HUVEC sheets from stimuli-responsive polymer layers and provide valuable options for the advanced engineering of vascular structures.

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In Situ Study of the Thermoresponsive Behavior of Micropatterned Hydrogel Films by Imaging Ellipsometry

Cited by 53 publications

References 43 publications

Thermo-responsive polymers and hydrogels in tissue engineering

Thermo-responsive polymers and hydrogels in tissue engineering

Hydrogel Films on Optical Fiber Core: Properties, Challenges, and Prospects for Future Applications

Detachment of human endothelial cell sheets from thermo-responsive poly(NiPAAm-co-DEGMA) carriers

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