What’s on the horizon for regenerative medicine?

Organo-electric nanowires.  (Tovar Lab/JHU)

Organo-electric nanowires. (Tovar Lab/JHU)

Editor’s Note: The following is a summary of one of the talks from the 2013 Nano-bio Symposium hosted by Johns Hopkins Institute for NanoBioTechnology held May 17. This summary was written by Christian Pick, a doctoral candidate in the chemical and biomolecular engineering laboratory of Joelle Frechette. Look for other symposium summaries on the INBT blog.

The fundamental goal of regenerative medicine is to allow the body to restore normal function to damaged or diseased tissues. Tissue scaffolds provide a structure for cells to grow on to accomplish this task. The pinnacle of scaffold function would be for the tissue grown from a scaffold to be completely indistinguishable from natural, undamaged tissue.

In order to improve scaffolds, researchers need to better understand how scaffolds interact with the body. Peter Gabriele, Director of Emerging Technology at Secant Medical, discussed FT-IR microscopy,  which is a unique tool that can help researchers with this very task.

Fourier transform infrared (FTIR) spectroscopy is a powerful technique for analyzing the chemical identity of materials. FTIR spectroscopy has been used for years in forensic analysis for identifying unknown samples. FTIR microscopy combines the functionality of FTIR spectroscopy with optical microscopy.

For the field of regenerative medicine, this means that the surface functionality of a scaffold can be mapped and studied throughout its entire lifetime: from production through degradation in-vivo. For instance, FTIR microscopy can be used to analyze surface modifications made to a scaffold during fabrication.

Additionally, it can be used to track tissue formation in implanted scaffolds. As an example, Mr. Gabriele described studies on “biorubber” or poly(glycerol sebacate) (PGS). FTIR microscopy has been used to identify collagen integration within the polymer during implantation as well as map the erosion of the material once implanted. Through the use of tools such as FT-IR microscopy, researchers can continue to expand the functionality of tissue scaffolds.

Secant Medical

Watch a video about INBT’s current research efforts in the realm of regenerative medicine here.

Lights! Camera! Science!


INBT Web Director Martin Rietveld works on protocol video with PhD student Yu-Ja Huang. (Photo:MSpiro)

Everything about movie making seems so glamorous. From beautiful stars to special effects, making films might appear magical. But actually, when you break it down, shooting a film is not unlike performing experiments in a lab. And, just as reading the script would be far less entertaining as seeing a film, reading a protocol might be confusing until the steps were performed in real life.

That’s the philosophy behind a new effort at Johns Hopkins Institute for NanoBioTechnology: produce short films describing recently published research and the protocols that go with them. The movies are produced collaboratively with INBT’s science writer Mary Spiro, INBT’s Animation Studio director Martin Rietveld, and the scientists and engineers involved.

The INBT Animation Studio already has several research-oriented films to its credit. The animation skills of Rietveld and his student crew have taken us inside a lipid bilayer and carried us along a fiber of collagen. INBT also has produced several video news releases using the talent of students in the annual science communication course.

Recently, however, INBT produced its first film describing a protocol from Nature Methods. Investigators Bridget Wildt, a PhD in materials science and engineering, Peter Searson, Reynolds Professor of Materials Science and Engineering, and Denis Wirtz, Smoot Professor of Chemical and Biomolecular Engineering, served as technical consultants for the production. The research was part of Johns Hopkins Engineering in Oncology Center, of which Wirtz is the director.

Materials science and engineering PhD candidate Yu-Ja Huang performs each step in assembling the Hopkins team’s device and demonstrates how to conduct programmed cell detachment experiments. “Studying cell detachment at the subcellular level is critical to understanding the way cancer cells metastasize,” Searson said. “Development of scientific methods to study cell detachment may guide us to prevent, limit or slow down the deadly spreading of cancer cells.”

Using a draft script developed by Wildt and Searson, Spiro simplified the text further for narrator, materials science and engineering PhD candidate Andrew Wong. Rietveld recorded Huang as he performed the protocol and refined the script further during filming. Viewing the final cut, Wong was able to read the script in a conversational and friendly tone.

You can watch the version of this new protocol video on INBT’s YouTube channel. The film may never earn an Academy Award, but we hope it will help specialists, and even the general public, to understand this unusual and complex procedure.

Related Links:

Check our INBT’s channel on YouTube.

Engineering in Oncology Center

Story by Mary Spiro

Probing the Soft Side with Nanoindentation Techniques

Michelle Oyen

Michelle L. Oyen of Cambridge University Engineering Department  will present the talk  ”Probing the Soft Side with Nanoindentation Techniques” on Wednesday, March 24 at 3 p.m. in Maryland Hall 110. Dr. Oyen is a lecturer in Mechanics of Biological Materials in the Mechanics and Materials Division and the Engineering for the Life Sciences group at Cambridge University. This seminar is hosted by Professor Tim Weihs and the Johns Hopkins University Department of Materials Science and Engineering. The talk is free and open to all Johns Hopkins faculty, staff and students.


The mechanical properties of many “soft” materials are of interest for biomedical applications, including both natural tissues and hydrogels for tissue engineering applications. In the last 15 years, nanoindentation techniques have gained prominence in the mechanical testing community for three reasons: first, the fine resolution in load and displacement transducers, second the fine spatial resolution for mapping local mechanical properties, and finally the relative ease of performing mechanical testing. In the current studies, we extend the scope of nanoindentation testing with commercial indenters to quantitative measurements on kPa materials. Different forms of the material constitutive response were considered with an emphasis on time-dependent viscoelastic or poroelastic deformation. Applications are the considered for hydrated tissues and hydrogels including articular cartilage, bone and mechanically graded hydrogels. Further investigations using adaptations of these nanoindentation techniques examine nano-scale adhesion and mechanical outcomes in stem cell differentiation. This study demonstrates the potential for high-throughput mechanical screening of soft materials and for mapping property gradients in inhomogeneous materials as these approaches can now be extended to materials in the kilopascal elastic modulus range.