Micropatterned material

Tan J, Saltzman WM. Topographical control of human neutrophil motihty on micropatterned materials with various surface chemistry. Biomaterials 2002 23 3215-25. 

Other ToF-SIMS studies of micropatterned materials for biological applications were presented in References... 

Folch A, Toner M (1998) Cellular micropatterns on biocompatible materials. Biotechnol Prog 14(3) 388-392... 

Electron beam (e-beam) irradiation of polymeric materials into specific micropatterns has been used to investigate the adhesive nature... 

In many cases it is necessary to synthesize porous materials in a well-defined preordered shape or within confined geometries, which introduces a pathway to fabricate hierarchically ordered porous materials. The techniques mentioned above have been shown to be capable of producing structured and well-ordered templates [61] within capillaries [50], thin plates [62], micromolds [63], or photoresist patterns [64,65]. Spatial adjustment of the surface functionality on the substrate and its wetting properties can yield patterned colloidal films [66,67]. Finally, confining the particle dispersion itself by printing techniques produces micropatterned arrays [68]. This was also shown to work without the necessity of preceding surface patterning steps [69]. 

Ubukata T, Hara M, Ichimura K, Seki T. 2004. Phototactic transport motions of polymer film for micropatterning and alignment of functional materials. Adv Mater 16 220 224. 

The most prominent technique among these is based on soft lithography [97]. This set of methods allows the generation of micropattemed polymer surfaces or microparticles of different shapes. Each method has certain limits such as scale and aspect ratio (cf. Table 3.5) that will be discussed in detail. Initially, two methods from soft lithography micropatterning and micromolding will be described, originally developed by Whitesides and coworkers. The technique relies on an elastomeric soft material that is either used as a stamp or as a mold in order to pattern surfaces 2D with a monolayer or 3D with a microstmcture (Fig. 3.65). In the first case, one can obtain a fine monolayer pattern (-lOOnrn) but no aspect ratio can be obtained. Nevertheless, by... 

The embossing ice particulates can be used to control the surface pore structures and to create micropatterned structures in porous scaffolds of naturally derived biodegradable polymers. When free ice particulates that are not embossed on a substrate are used, the inner body pore structures of biodegradable polymers can be controlled. In this case, preprepared ice particulates are used as a porogen material. The ice particulates are mixed with precooled polymer solution. The mixture is subsequently frozen slowly and freeze-dried. This method has been used to prepare porous scaffolds of biodegradable synthetic polymers and biodegradable naturally derived polymers [16-18,22]. 

Surface graft polymerization of poly(ethylene glycol) acrylate was used to modify the surface of PDMS. Templates with channels were formed from this material and sol-gel chemistry was used to form amino-silane doped xerogel microarrays. These structures were then used to release nitric oxide at various rates, by control of micropattern dimensions, type and concentration of the amino-silane, and so on. This method parallels the use of polymers in controlled drug-delivery systems. ... 

The use of polymeric materials in microchips has gained popularity, especially in the fabrication of low-cost, disposable devices [3], It is particularly common to prototype polydimethylsiloxane (PDMS) chips, which can easily be fabricated using the soft lithography technique. This fabrication strategy is considered as a low-expertise route of microscale prototyping. It facilitates creation of micropatterns on a surface or within a microfluidic channel without the need for using photochemical processes [9]. Fabrication... 

Specific types of polymer micropatterns were made of crosslinked and uncrosslinked poly(methacrylic acid) and poly(N-isopropyl acrylamide) or polyNI-PAM. Also, the spacer material between the Si wafers was adjusted to hundreds of micrometers, allowing for a single-exposure high aspect ratio microlithography of theses polymers. Also, since these polymers under go LCST behavior during polymerization conditions, they are suitable as thermoreversible gels during application. 

In 2006, a facile method for trapping the crosslinked PLCPs in surface microstructures via micropatterning was reported [42]. The confinement of crosslinked PLCP materials into surface monodomains enables the formation of reversible shape-shifting surface patterns. Upon the irradiation of UV light, the crosslinked PLCP monodomains were photoinduced into an isotropic state, resulting in a feature to switch between imprinted circular feature and anisotropic liquid crystalline feature. 

In fact, desolvated or activated samples (e.g., the supercritical carbon dioxide method), exchange of guest particles (including molecules, cations and ions) from host materials, " micropatterning [i.e., introduction of large guests or the formation of metal nanoparticles ), building block replacement etc. have all been performed in a post-... 

Biological systems provide numerous examples of micropatterned inorganic materials that directly develop into their intricate architectures, as illustrated by skeleton formation in echinoderms with component function of speciahzed photosensory organs [19,248]. Each skeletal structural unit (spines, test plates) is composed of a single caldte crystal delicately patterned on the micrometer scale, which is composed of a close-set array of hemispherical caldtic structures (40-50 pm in diameter) with a characteristic double-lens design (Fig. 20). 

Such biomimetic synthetic microlens arrays could be potentially used as highly timable optical elements for a wide variety of appUcations [246,247, 249]. The successful fabrication of micropatterned single crystals resembling the natural echinoderm calcitic structures demonstrated that the inspiration from Nature s methods of biological manufacture is proving to be a rich reservoir for the fabrication of advanced materials and devices with novel and superior properties. 

Currently, the most popular and widely used micropatterning technique is microcontact printing [63]. A PDMS stamp with designed microstructures can be used to print various types of molecules on the chosen material. An example of microcontact printing onto polycarbonate surface will be given in Section 3.7.3. 

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