Biomedical subjects

B A Grzybowski

Publications and source records attributed to B A Grzybowski.

6 recordsLinked to original sources

PubMed2006

Localized chemical wave emission and mode switching in a patterned excitable medium.

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.

Animals↗

PubMed2006

Microchameleons: nonlinear chemical microsystems for amplification and sensing.

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."

Absorption↗

PubMed2005

Wet stamping of microscale periodic precipitation patterns.

Although periodic precipitation (PP) phenomena have long attracted scientific interest, their study has been limited to macroscopic systems and simple geometries. An experimental method was developed that allows the generation of highly regular, microscopic PP patterns of arbitrary geometries. Generic scaling laws were established that related the morphologies and topographies of the PP patterns to the geometrical parameters of the system. It was possible to control PP at the level of stochastic phenomena and thus to induce micropatterns of desired chiralities and to control the propagation of defects in them. A 3D nucleation-and-growth model was developed that faithfully reproduced the patterns observed in experiments.

Journal Article↗

PubMed2004

Absorption of water by thin, ionic films of gelatin.

This paper discusses absorption of water by thin, dry films of gelatin. Experiments using a wet-stamping technique were performed to characterize water uptake in terms of (i) equilibrium profiles of the water density inside the gel and (ii) the kinetics of water absorption. It was found that, in contrast to pure gelatin films, which absorb water approximately uniformly, films of gelatin doped with ionic additives have exponentially decaying equilibrium water profiles. The process of water absorption by both doped and undoped gels was described by a theoretical model based on the minimization of grand potential functional. The results of this model are in agreement with the experiment.

Gelatin↗

PubMed2001

Dynamic, self-assembled aggregates of magnetized, millimeter-sized objects rotating at the liquid-air interface: macroscopic, two-dimensional classical artificial atoms and molecules.

This paper describes self-assembly of millimeter-sized, magnetized disks floating on a liquid-air interface, and rotating under the influence of a rotating external magnetic field. Spinning of the disks results in hydrodynamic repulsion between them, while the rotating magnetic field produces an average confining potential acting on all disks. The interplay between hydrodynamic and magnetic interactions leads to the formation of patterns. Theoretical analysis of hydrodynamic and magnetic forces indicates that the interactions in this system are similar to those acting in systems of finite numbers of particles behaving classically ("classical artificial atoms"). Macroscopic artificial atoms and molecules are described, and the rules governing their morphologies outlined.

Journal Article↗

PubMed2000

Modeling the kinetics of acylation of insulin using a recursive method for solving the systems of coupled differential equations.

This paper describes a theoretical method for solving systems of coupled differential equations that describe the kinetics of complicated reaction networks in which a molecule having multiple reaction sites reacts irreversibly with multiple equivalents of a ligand (reagent). The members of the network differ in the number of equivalents of reagent that have reacted, and in the patterns of sites of reaction. A recursive algorithm generates series, asymptotic, and average solutions describing this kinetic scheme. This method was validated by successfully simulating the experimental data for the kinetics of acylation of insulin.

Acylation↗