Closer to Nature–Bio‐inspired Patterns by Transforming Latent Lithographic Images

Abstract

Inspired by nature, a new strategy to create three‐dimensional organic structures spanning orders of magnitude by using a combination of deep UV or X‐ray direct lithography with a solid‐state forming process. The stored latent lithographic image is transferred to three‐dimensional curvilinear surfaces by forming the irradiated film under conditions of permanent material coherence.

Large‐Scale Fabrication of Three‐Dimensional Surface Patterns Using Template‐Defined Electrochemical Deposition

“…For example, the size and shape of noble metals in a surface pattern will significantly influence the optical properties of photonic structures and metamaterials;9–17 the density of nanostructures in a surface pattern will affect the performance of field‐emitting devices 19. In the past decade, tremendous efforts have been devoted to developing techniques that can be used to fabricate and precisely control the structure of surface patterns 20–31. In particular, there is significant interest in developing three‐dimensional (3D) surface patterns, which often exhibit properties that are difficult to obtain with their two‐dimensional (2D) or one‐dimensional (1D) counterparts.…”

DNA-SMART: Biopatterned Polymer Film Microchannels for Selective Immobilization of Proteins and Cells

“…Typical procedures for DNA patterning of flat glass surfaces include plasma activation of the solid support, which is then followed by functionalization using organo‐trialkoxysilane reagents, such as aminopropyl‐triethoxysilane (APTES) and subsequent installment of reactive crosslinkers, bearing for instance N ‐hydroxysuccinimide or epoxy groups . To adopt this chemistry to polymer surfaces, we tested four different commercially available polymer films, polycarbonate (PC), cyclic olefin polymer (COP), polypropylene (PP), and polystyrene (PS), all of which are transparent and have previously been used as materials for microthermoforming and conventional cell culture products . Square‐cut sheets of these films (about 2 × 2 cm 2 ) were subjected to plasma treatment, followed by silanization with APTES and, in case of COP and PC, activation with bis‐epoxy‐poly(ethyleneglycol) (EPEG) ( Figure A).…”

“…As a particular advantage, the mild forming conditions of microthermoforming allow one to preserve chemical and structural premodifications of the film material while it is processed by microreplication. This has led to the establishment of SMART (substrate modification and replication by thermoforming) technology, which enables for example the implementation of latent lithographic images into the large‐scale production of microdevices bearing complex, bioinspired patterns . For instance, in a previously developed SMART module, the site‐specific, covalent coupling of a single type of bioactive moieties on defined gray‐scale patterns with a lateral resolution of 7.5 µm were produced on the inner curvilinear surfaces of thin film microchannels by a combination of microthermoforming with maskless projection lithography and protein adsorption by photobleaching.…”

Overlooked? Underestimated? Effects of Substrate Curvature on Cell Behavior

“…Fabrication methods for such curved concave and/or convex structures are, among others, mechanical micromachining [37], (photo)lithography followed by isotropic wet etching or dry etching, for example as locally lagged reactive ion etching ( Figure 3AE) [38], or followed by melting or thermal reflow of photoresist [17,39], gray-scale/tone lithography [40], laser (micro)machining/ablation [41], a-particle radiation with subsequent chemical etching of the latent particle tracks [42], microtunable mold-derived techniques ( Figure 3B) [16,43], structuring of concave microwells by squeezing or raking out PDMS precursor of the microcavities followed by forming of a surface-tension induced precursor meniscus [44,45], other soft lithography-based methods [46], molding based on water molds generated by microscale plasma-activated templating [47], ice lithography [48], free-forming variants of microthermoforming of thin polymer films ( Figure 3C) [49], stereolithography and 2PP laser lithography [50] ( Table 1). Microthermoforming allows the creation of cell substrates combining, for example, curvature and micro-/nanotopographies [51,52] or (bio)chemical micropatterns [53]. Further, it enables the creation of microanatomically curved porous substrates for 3D epithelial and/or endothelial barrier studies [54,55].…”