CFM incorporates a miniature microscope and camera into a swinging-bucket centrifuge. Colloidal particles in suspension interact with the interior surface of a sample cell, which is loaded into the CFM. The effective gravity produced by the centrifuge pulls the colloidal particles away from the interior surface, and the camera records these detachments. In this way, interaction forces of colloids are measured. Van der Waals and electrostatic interaction forces, as well as depletion interactions, are among the forces that can be characterized.
Leafy Spurge is a noxious weed that grows throughout most of the United States. Using an explosive seed dispersal process called dehiscing, it can launch seeds up to 15 ft. We use high-speed imaging, magnetic resonance imaging (MRI), and stereo microscopy to study how the mechanisms and structures in the seed pod cause this explosive dispersal.
Hydrogels are soft, water-based gels with widespread applications in personal care products, medicine and biomedical engineering. Many applications require structuring the hydrogel into complex three-dimensional (3D) shapes. For these applications, light-based 3D printing methods offer exquisite control over material structure. All kinds of biological applications within hydrogel require to have open channels to feed the implanted cells and remove the waste. However, having these openings are challenging due to nature of SLA 3D Printing. Here is a video, showing successfully achieved open spiral channels within 600 um resolution.
Most soft materials, such as emulsions, polymers, gels, and biological tissues are characterized by structures at an intermediate length scale, larger than individual atoms and small molecules, but too small to be resolved by eye. These microscopic structures are easily perturbed by weak external fields. We use microscopy and scattering techniques to study structure-function relationships in a variety of soft materials.
Small angle neutron scattering (SANS) is a technique for characterizing length scales on the order of 1 nm to 100 nm and is ideal for characterizing the internal structure of dense, opaque samples. Time-resolved SANS can be used to obtain dynamic information. We conduct SANS measurements at Oak Ridge National Lab in Knoxville, TN and the National Institute of Standards and Technology in Gaithersburg, MD to characterize the structure and dynamics of extracellular matrix components, engineered composites and a variety of soft materials.
Millifluidic chips allow us to culture and monitor millimeter-scale tissues in well-controlled fluidic environments. We use a laser cutter and 3D printer to rapidly prototype millifluidic designs. We collaborate with the Chang Microfluidics Lab to create hybrid microfluidic/millifluidic devices using photolithography.
Mechanical forces play critical roles in the development of multicellular communities. We use time-lapse light and fluorescence microscopy to track the growth of millimeter-scale eukaryotic tissues and apply micromechanical measurement techniques such as traction force microscopy and microrheology to explore the role of mechanics in tissue development and morphogenesis.
Most bacteria do not exist as free swimming individuals, but on surfaces in soft, gel-like communities called biofilms. These films are implicated in a tremendous number of health and industrial problems such as hip implant infections and oil pipeline deterioration, but they also play beneficial roles in sewage treatment and agricultural plant protection. For both beneficial and problematic biofilms, knowledge of their mechanical response to physical forces is critically important, yet greatly lacking. Our research in this area aims to address this knowledge gap by using micromechanical measurements to develop a fundamental,… Read More