RESUMO
Chemical waves are initiated from complex geometries in the excitable Belosouv-Zhabotinsky medium using a wet stamping technique. Because of the coupling between the system's chemical kinetics and geometry, waves are emitted only from selected locations. By varying the nature of the wave-triggering reagent (here formaldehyde or methanol), it is possible to switch between two spatially distinct modes of wave emission. The system's dynamics is studied numerically, and the results of modeling agree with experimental observations.
Assuntos
Biofísica/métodos , Animais , Catálise , Agregação Celular , Físico-Química/métodos , Quimiotaxia , Simulação por Computador , Meios de Cultura , Dictyostelium/metabolismo , Formaldeído/química , Cinética , Metanol/química , Modelos Biológicos , Modelos Químicos , Sefarose/química , Fatores de TempoRESUMO
In biological systems, the coupling of nonlinear biochemical kinetics and molecular transport enables functional sensing and "signal" amplification across many length scales. Drawing on biological inspiration, we describe how artificial reaction-diffusion (RD) microsystems can provide a basis for sensing applications, capable of amplifying micro- and nanoscopic events into macroscopic visual readouts. The RD applications reviewed here are based on a novel experimental technique, WETS for Wet Stamping, which offers unprecedented control over RD processes in microscopic and complex geometries. It is discussed how RD can be used to sense subtle differences in the thickness and/or absorptivity of thin absorptive films, amplify macromolecular phase transitions, detect the presence and quality of self-assembled monolayers, and provide dynamic spatiotemporal readouts of chemical "metabolites."
Assuntos
Bioquímica/métodos , Biofísica/métodos , Técnicas Biossensoriais , Eletroquímica/métodos , Absorção , Difusão , Humanos , Cinética , Microquímica/métodos , Modelos Biológicos , Modelos Teóricos , Dinâmica não Linear , Física/métodos , Propriedades de Superfície , TemperaturaRESUMO
Hydrogel stamps can microstructure solid surfaces, i.e., modify the surface topology of metals, glasses, and crystals. It is demonstrated that stamps soaked in an appropriate etchant can remove material with micrometer-scale precision. The Figure shows an array of concentric circles etched in glass using the immersion wet stamping process described (scale bar: 500 µm).