Integrated Calendar

Precise control of the delivery and transport of materials in the nano and micro scales is crucial for realizing miniaturized device technologies such as ‘lab on a chip’ and micro-factories, and for understanding, analyzing and manipulating transport processes in microscale biological systems. In my talk I will discuss two mechanisms which employ chemical energy to produce autonomous transport. In the first part of the talk, I will describe the use of chemical potential gradients for establishing directional transport by converting chemical potential into mechanical energy. I will present a general theoretical framework for describing the transport of chemical species along a two–dimensional gradient, and analyze the effect of the gradient on enhancing collection of analyte molecules and polymers in nano-sensors. The strength of the model for analysis of experimental results will be demonstrated for hydrogels modified with a chemical gradient of binding sites, and the insights obtained from the theoretical predictions will be discussed.
In the second part of the talk I will present a novel type of biodegradable micro-rockets that exhibit autonomous movement through catalytic bubble-thrust propulsion. Using electrospinning, we fabricated core/shell biodegradable polymeric microtubes which exhibit different chemistries on their interior and exterior surfaces. I will discuss the different chemical modifications which can be obtained and their applications. In particular I will focus on the ability to chemically bind inorganic catalytic nanoparticles or enzymes selectively inside the tubes, which upon exposure to hydrogen peroxide lead to propulsion of the tubes by oxygen bubbles expulsion. I will compare the effect of different catalysts on the obtained velocity, and discuss the ability to use different fuels and catalysts for clean propulsion in biological environments.