Columbia University – TechConnect Briefs

Rapid prototyping bacterial spore hygro-actuators for soft robotics and adaptive materials

Cavusoglu A.‐H., Chen X., Tatem K., Sahin O., Columbia University, US

Over the past decade, rapid prototyping has migrated from the research and industrial labs into the homes of consumers. However, these solid models are limited in demonstrating dynamic actuation. A large range of soft materials [...]

Potential of Water‐Responsive Materials to Harvest Energy from Evaporation

Cavusoglu A.‐H., Chen X., Sahin O., Columbia University, US

Water-responsive materials swell and shrink in response to changes in relative humidity (RH) and can be potentially used to harvest energy from evaporating water. Here, we investigated the potential of harvesting energy from naturally evaporating [...]

Generation of picoliter and nanoliter drops on-demand in a microfluidic chip

Xu J., Attinger D., Columbia University, US

In this work, we introduce the novel technique of in-chip drop-on-demand, which consists in dispensing picoliter to nanoliter drops on demand directly in the liquid-filled channels of a polymer microfluidic chip. The technique involves a [...]

Modeling evaporation and ring-shaped particle deposition of a colloidal microdroplet, with applications in biological assays

Bhardwaj R., Attinger D., Columbia University, US

Colloidal drops evaporating on a solid substrate can be used as vehicles for dispensing or organizing small particles suspended within them. The pattern left after evaporation can be a ring-like structure such as the dried [...]

A Bio-Inspired Rotor Powered by a Micro-Bubble

Kao J., Warren J., Xu J., Attinger D., Columbia University, US

We present and characterize a novel micro-rotor actuation concept, where acoustic oscillations of a micro-bubble produce a steady fluid flow driving a microfabricated rotor at a rotating speed as high as 600 rpm. Developing micro-machines [...]

On the Motion of a Bubble through Microchannel Contractions

Chio H., Jensen M.J., Wang X., Bruus H., Attinger D., Columbia University, US

We present the first transient pressure measurements and high-speed visualizations of a gas bubble passing through liquid-filled microchannel contractions. Results are compared with a simple theoretical model taking into account the Young-Laplace pressure drop, the [...]

Role of immunoregulators as possibility of tumor hypoxia-induced apoptosis

Sharma R., Kwon S., Chen C-J., Columbia University, US

IL-1, TNF-α and INF-γ cytokines stimulate in nitric oxide production and result with inflammation manifested by apoptosis and hypoxia. We propose that extent of inflammation leading to hypoxia initially and programmed cell death later both [...]

Apoptosis Characterization by Flouro-deoxy Glucose and Intracellular Sodium Distribution Using MicroPET/MRI in PC3 Induced Prostate Cancer in Mice Tumor

Sharma R., Kline R.P., Katz J.K., Columbia University, US

Background: Intracellular sodium (IC) and FDG accumulate in premalignant tumor sites. Hypothesis: High FDG and IC accumulation may characterize tumor stages. Objective: To develop rapid noninvasive hybrid microPET/MRI method to characterize PC3 tumor in mice. [...]

Analytical and FEM Simulation Pull-in Study on Deformable Electrostatic Micro Actuators

Cheng J., Zhe J., Wu X., Farmer K.R., Modi V., Frechette L., Columbia University, US

In this paper, we employed an easy general theory [1, 2] over FEM simulation to carry out the pull in analysis of cantilever beam, fixed-fixed beam and circular membrane actuators and compare the results with [...]

Analytical Pull-in Study on Non-Deformable Electrostatic Micro Actuators

Zhe J., Wu X., Cheng J., Wang J., Farmer K.R., Frechette L., Modi V., Columbia University, US

A general theory and method was presented and employed to analyze the static behaviors of non-deformable electrostatic actuator systems with various electrode shapes. This method utilizes capacitance-based generalized equations and provides an easy and time [...]