Materials science student wins Acta Student Award

Heemin Kang

Heemin Kang, a materials science graduate student at UC San Diego, has received an Acta Student Award. Kang is among 11 awardees who were selected for their contributions to papers published in Acta journals in 2014. Each award comes with a $2,000 cash prize and will be presented during an awards ceremony on Oct. 5 at the Materials Science & Technology meeting in Columbus, Ohio.

Kang was selected to receive the award for his work on biomimetic materials that induce stem cells to become bone-building cells. The research, led by bioengineering professor Shyni Varghese, was reported in the manuscript titled, “Mineralized gelatin methacrylate-based matrices induce osteogenic differentiation of human induced pluripotent stem cells,” which was published in the journal Acta Biomaterialia in Aug. 2014. Kang was the first author on this paper.

In this work, Kang and co-workers in Varghese’s Bio-Inspired Materials and Stem Cell Engineering Lab engineered matrices consisting of calcium phosphate minerals. Stem cells that were grown on these biomineralized materials transformed into cells that can build new bone.

“These engineered materials, coupled with stem cells, can be used to treat patients with critical bone defects and traumatic bone fractures,” said Kang. “This work is an exciting step towards accelerating stem-cell-based regenerative therapies.”

Left: Image of engineered bone-mimetic material containing calcium phosphate minerals. Right: Image of bone cells derived from the conversion of human induced pluripotent stem cells by the engineered mineralized material. Osteocalcin, a protein that can be solely produced by bone-forming cells, is shown in green.

Moreover, these materials are able to convert stem cells into bone-building cells in the absence of any bone-stimulating proteins or biochemicals. “Our study is the first to demonstrate a simple way to induce pluripotent stem cell differentiation, both in vitro and in vivo, using only these engineered biomaterials,” said Kang.

Kang’s interest in regenerative medicine was inspired by his time serving as a sergeant in the U.S. Army, where he encountered many injured soldiers. His aim is to become a professor and continue developing biomaterial-based regenerative therapies that can be used to treat injured soldiers and other patients suffering from bone defects and disorders.

Read more about related work in Varghese’s lab here.

Giving human stem cells a massage to release calcium

Mesenchymal stem cells—adult stem cells that are constantly renewing our bone, cartilage, and muscle—can be stimulated by a gentle massage to release calcium. Bioengineers at UC San Diego published their findings in the February issue of eLife and their work has been recently featured online in BioTechniques.

Understanding how mesenchymal stem cells respond to physical forces in the body, such as blood flow or exercise, is important for a variety of diseases ranging from diabetes to spinal cord injury. Research led by Yingxiao (Peter) Wang, associate professor of bioengineering, shows exactly how pushing and pulling the outsides of these cells can signal changes inside them. For example, a gentle tug on the outer membrane of these cells opens up channels to release calcium ions stored within the cells. 

Read the recent story, which also mentions Wang's upcoming summer workshop on single cell imaging for graduate students and postdocs, in BioTechniques here. More information on this work is also available in the Jacobs School press release from February and in the full paper published in eLife: “Distinct mechanisms regulating mechanical force-induced Ca2+ signals at the plasma membrane and the endoplasmic reticulum in human mesenchymal stem cells.”