Science

Bridging the Gap

~ saracody

Cells Build Bridges to Heal Damaged Tissue

The world can be a dangerous place. With more than 41 million visits to the emergency department due to trauma in the U.S. each year, it is crucial to study the process of wound healing and how medical intervention might facilitate it. A study led by Professor Christopher Chen (BME), published inNature Communications, points to a promising new direction researchers could use to better understand wound healing.

Chen and his research team have developed a three-dimensional microtissue culture that mimics the healing process more closely than the traditional two-dimensional culture of cells that researchers have long used.

“Healing wounds requires the human body to fill 3D spaces, so we reasoned that healing of wounded 3D microtissues would more closely resemble wound healing in the human body,” says Chen. “This finding has the potential to become the new standard to study wound healing in vitro.”

First, the research team bioengineered a unique cell culture system in which 3D microtissues are formed from wound repairing cells called fibroblasts embedded in a matrix of collagen fibers, similar to how they exist in the human body. Next, Selman Sakar from the Swiss Federal Institute of Technology in Lausanne and Jeroen Eyckmans, senior postdoctoral associate in Chen’s Tissue Microfabrication Lab, leading authors of this study, cut tiny holes in the microtissues and captured time-lapse videos of the reaction under a microscope. The images showed the fibroblast cells closing the gap and healing the tissue without any signs of scarring. The process of healing observed in these microtissues was surprisingly different from healing previously observed in cells cultured on traditional 2D surfaces.

“When we did the same molecular manipulations in a single-layer sheet of cells, key players that sped up healing in 3D actually slowed healing of the sheet,” says Eyckmans. “Also, the restoration of 3D tissue architecture that is absent in 2D but occurs in our microtissues is of high interest when thinking about how to induce tissue regeneration rather than scarring.”

Digging deeper, they looked at what might be happening with another scaffolding molecule called fibronectin, which plays a large role in wound healing. They found that the fibroblast cells were dismantling fibronectin present in microtissue and towing it in to the wound, using it to build a bridge to connect to the opposite side of the gap. The fibroblast cells flocked to the bridge and began producing their own fibronectin, completely filling in the wound until the defect returned to its three-dimensional form, completely restoring the wounded tissue.

“What was most surprising was that the cells didn’t just move in to close up the hole; they remodeled the entire matrix, modifying their environment to close the gap,” says Eyckmans. “This provides a new approach to studying wound healing and standardizing this practice in research could lead to many important insights in this field.”

While this technology would not be directly incorporated into patient care, future work could be done to develop this model into a research tool to explore a variety of questions, from scar formation to how the process could impact the speed of wound healing to the role various stresses play in the healing process.

Boston University College of Engineering

Originally Posted: March 25, 2016

Appears on: BU ENG News website

Naturally Inspired

~ saracody

Zhang’s Research Takes a Page from Biology to Build Materials

At first glance, diatoms seem to have little to do with engineering. However, to Professor Xin Zhang, (ME, MSE), they are the central focus of a recently published study coming from her Laboratory for Microsystems Technology.

“By drawing inspiration from different fields of science, we come up with unconventional approaches to study the materials, which allows us to learn more about them,” says Zhang. “In this case, we learn from nature to build materials of our own.”

The study, published as the cover story inExtreme Mechanics Letters, used the exoskeletons of diatoms called frustules to develop a stencil that can be easily produced and replicated in a certain range of sizes for use in research protocols. The porous, bowl-shaped, three-dimensional exoskeletons, made naturally of pure silica, lent themselves well to stencil-making, and served as a unique fabrication method.

“The ability to uniformly orient the frustules will be beneficial for enhancing their application to practical technologies, from sensors to solar cells,” says Aobo Li (ME), a graduate student who worked on the study. “We were able to figure out how to orient them uniformly on a large scale, which allowed us to make micro- and nanostencils.”

Current methods of creating nanopattern surfaces presented a number of problems for researchers—they can be costly, time-consuming, or it can be hard to achieve scalability or control over the size of the stencil. Zhang’s novel approach seeks to address these limitations by using the bio-structures of the diatoms as a potential alternative for fabricating micro- and nanopatterns.

“You can make chips, you can make computers but if you humbly turn to nature, you see so many unique micro- and nanostructures that already exist,” says Zhang. “You can be inspired by these beautiful, available structures and can even build engineering components directly out of them. By looking to diatoms, we are trying to understand nature and leverage these biological components for our specific engineering purposes.”

 

Boston University College of Engineering

Originally Posted: January 12, 2016

Appears on: BU ENG News website, ENGineer Magazine Spring 2016

Big Things in Small Packages

~ saracody

Walsh Wins NASA Grant to Get a Wider View of Earth

Assistant Professor Brian Walsh (ME) plans to develop and launch a small x-ray imaging spacecraft to study the interaction between solar wind and the Earth’s magnetic field under a 4-year, $2.4 million NASA grant.

The goal of Cusp Plasma Imaging Detector (CuPID) is to use a wide-field-of-view x-ray telescope to learn how energy from the sun is transferred into the near-Earth space environment. Though astronomers have long used x-ray technology to collect data in space, Walsh’s approach is unique.

“In the past, x-ray telescopes on satellites have only had tiny, pencil-beams fields of view, which limited them to only collecting data in their immediate area,” says Walsh. “We have created the first wide-field-of-view x-ray detector, which will allow us to look at the big picture all at once. This will allow us to gain an understanding of the interaction between the sun and the Earth’s magnetic field and will assist in designing future spacecraft that can withstand the harsh space environment.”

Walsh, who is concurrently working with Professor Joshua Semeter (ECE) on small satellite research, will spearhead the project. He anticipates that researchers and students across a variety of disciplines at BU will work together to build the spacecraft while collaborating with partner institutions.

The mission, which is scheduled for launch in 2019, is being led by Boston University and involves collaborations from the NASA Goddard Space Flight Center, Johns Hopkins University, Drexel University and Merrimack College.

 

Boston University College of Engineering

Originally Posted: January 11, 2016

Appears on: BU ENG News website, ENGineer Magazine Spring 2016