Professors’ Nguyen, Gracias and Schulman work on active hydrogels featured in ACS’ Chemical and Engineering News

Harnessing the power of shape-shifting polymers

” …Research teams such as those of David Gracias and Thao (Vicky) Nguyen at Johns Hopkins University have already shown the potential utility of pNIPAM-based grippers. The points of the star-shaped devices curl inward like a claw when activated. “Let’s say you want to capture a biopsy of a tumor,” Nguyen says. “You could have patients swallow these grippers and guide them to the right tumor so that they can actually grip the tumor and pull some cells off….”

Nguyen Lab Mug

December 18 2017

We have a Lab mug, designed by 2017 lab members!  See photo album page for the full story.  Contact Vicky Nguyen if you’re a lab alumni and would like one.

Lab Alumni awarded the ASME Y. C. Fung Young Investigator Award

The 2017 Y.C. Fung award recognizes Prof. Myers “pioneering efforts in maternal and fetal health, resulting in a body of experimental and modeling work that drives the area of reproductive biomechanics and the larger field of soft tissues biomechanics.”  Read all about it here. Professor Myers was a postdoctoral fellow in the Nguyen Lab from 2008-2010 and is currently an Associate Professor in the Department of Mechanical Engineering at Columbia University.

NSF grant for 3D printing

Professor Nguyen (PI), Hemker, Kang, and Robbins receives NSF DMREF grant to study the effect of printing conditions on the mechanical properties of 3D printed polymers

Link to ME Department announcement

NSF Abstract of the project

Barbara Murienne successfully defended her dissertation

March 1, 2016
IMG_4229Barbara Murienne successfully defended her dissertation, titled “Glycosaminoglycan Contribution to the Structure- Mechanical Properties of the Posterior Sclera” on March 1, 2016 at 11:00 am in Malone 328. The abstract is below.

Congratulations Barbara! It was a great talk.

The sclera is the white outer shell and main load-bearing tissue of the eye. It resists the intraocular pressure, therefore maintaining the integrity of the eye, and protects the more fragile intraocular structures, such as the retina, from external forces. Alterations to the scleral mechanical properties can lead to the initiation and development of ocular pathologies such as myopia, often characterized by an axial elongation of the globe, or glaucoma, where the transmission of the visual information to the brain is impaired by a detrimental mechanical environment at the optic nerve head, at the back of the eye. While studies reported alterations in the mechanical properties of the posterior sclera of glaucomatous and myopic eyes, others measured alterations in its microstructure, including the glycosaminoglycan (GAG) content. The contribution of collagen and elastin to the mechanical behavior of connective tissues is well known and consistent among tissues. However, the mechanical role of GAGs is tissue- dependent and has never been studied in the sclera. Therefore, this work aims to investigate the contributions of GAGs to the structure and mechanical properties of the posterior sclera and their possible role in glaucoma and myopia.

This work developed experimental and numerical approaches to measure the structural and mechanical effects of sulphated glycosaminoglycans (s-GAGs) digestion in the posterior sclera. A setup was first developed to compare the two-dimensional (2D) and three-dimensional (3D) versions of digital image correlation (DIC) for a membrane under inflation. Although 2D-DIC can be useful to evaluate the profile behavior of materials inflated under experimental conditions that discourage the use of a stereovision system, only 3D-DIC can capture the 3D heterogeneous anisotropic mechanical behavior of the sclera. A protocol for s-GAG digestion was then developed and the inflation response of posterior scleral shells from pig and human eyes was measured before and after s-GAG degradation using 3D-DIC displacement tracking. Structural parameters such as the scleral thickness and hydration were measured. A methodology was developed to evaluate the error and uncertainty in strains due to the 3D-DIC displacement error and uncertainty for our posterior scleral shells under inflation. An inverse finite element method (FEM) was finally applied to specimen-specific meshes of the porcine scleral shells to determine the effect of s- GAG degradation on the properties of the matrix and collagen components of the posterior sclera. We concluded from this work that despite their low content compared to other structural components, s-GAG play a measurable role in the structure and mechanical properties of the posterior sclera. s-GAGs affect the scleral properties mainly through their effects on hydration and their interactions with the collagen fibrils, and could be involved in the altered mechanical behavior observed in glaucoma and myopia.

Congratulations to our newest professors!

This academic job season has yielded great results for two postdoctoral fellows from our lab. Dr. Sarah Bentil will be joining the Mechanical Engineering Department at Iowa State University this fall as an Assistant Professor. Dr. Aurelie Azoug will be joining the Mechanical Engineering and Aerospace Department of Oklahoma State University this fall as an Assistant Professor as well.

Congratulations to Aurelie and Sarah for their accomplishments and perseverance!

Doctoral Hooding Ceremony 2015

May 20, 2015

Congratulations to Dr. Rui Xiao  and Dr. Theresa Tonge on their PhD.