Tag Archives: Congzhou Wang

Eliminate cold storage for diagnostic tests?

Leave a reply

There’s a nanoparticle coating that could eliminate the need for cold storage and/or refrigeration for diagnostic testing according to a Jan. 4, 2017 news item on Nanowerk,

Many diagnostic tests use antibodies to help confirm a myriad of medical conditions, from Zika infections to heart ailments and even some forms of cancer. Antibodies capture and help detect proteins, enzymes, bacteria and viruses present in injuries and illnesses, and must be kept at a constant low temperature to ensure their viability — often requiring refrigeration powered by electricity. This can make diagnostic testing in underdeveloped countries, disaster or remote areas and even war zones extremely expensive and difficult.

A team of engineers from Washington University in St. Louis and Air Force Research Laboratory have discovered an inexpensive work-around: a protective coating that could completely eliminate the need for cold storage and change the scope of medical diagnostic testing in places where it’s often needed the most.

“In many developing countries, electricity is not guaranteed,” said Srikanth Singamaneni, associate professor of mechanical engineering and materials science in Engineering & Applied Science at Washington University in St. Louis.

“So how do we best get them medical diagnostics? We did not know how to solve this problem previously.”

A Jan. 4, 2016 Washington University in St. Louis news release by Erika Ebsworth-Goold, which originated the news item, describes how previous research helped lead to a solution,

Singamaneni’s team previously used tiny gold nanorods in bio-diagnostic research, measuring changes in their optical properties to quantify protein concentrations in bio-fluids: the higher a concentration, the higher the likelihood of injury or disease.

In this new research, published in Advanced Materials, Singamaneni worked with faculty from Washington University’s School of Medicine and researchers from the Air Force Research Lab to grow metal-organic frameworks (MOFs) around antibodies attached to gold nanorods. The crystalline MOFs formed a protective layer around the antibodies and prevented them from losing activity at elevated temperatures. The protective effect lasted for a week even when the samples were stored at 60°C.

“This technology would allow point-of-care screening for biomarkers of diseases in urban and rural clinic settings where immediate patient follow-up is critical to treatment and wellbeing,” said Dr. Jeremiah J. Morrissey, professor of anesthesiology, Division of Clinical and Translational Research, Washington University School of Medicine and a co-author on the paper.

“On the spot testing eliminates the time lag in sending blood/urine samples to a central lab for testing and in tracking down patients to discuss test results. In addition, it may reduce costs associated with refrigerated shipping and storage.”

The protective MOF layer can be quickly and easily removed from the antibodies with a simple rinse of slightly acidic water, making a diagnostic strip or paper immediately ready to use. Singamaneni says this proof of concept research is now ready to be tested for clinical samples.

“As long as you are using antibodies, you can use this technology,” said Congzhou Wang, a postdoctoral researcher in Singamaneni’s lab and the paper’s lead author. “In bio-diagnostics from here on out, we will no longer need refrigeration.”

“The MOF-based protection of antibodies on sensor surfaces is ideal for preserving biorecognition abilities of sensors that are designed for deployment in the battlefield,” said Dr. Rajesh R. Naik, 711th Human Performance Wing of the Air Force Research Laboratory, Wright-Patterson Air Force Base, and a co-corresponding author of the paper.  “It provides remarkable stability and extremely easy to remove right before use.”

Here’s a link to and a citation for the paper,

Metal-Organic Framework as a Protective Coating for Biodiagnostic Chips by Congzhou Wang, Sirimuvva Tadepalli, Jingyi Luan, Keng-Ku Liu, Jeremiah J. Morrissey, Evan D. Kharasch, Rajesh R. Naik, and Srikanth Singamaneni. Advanced Materials DOI: 10.1002/adma.201604433 Version of Record online: 7 DEC 2016

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

A final observation, there’s at least one other project aimed at eliminating the need for refrigeration in the field of medical applications and that’s the nanopatch, a replacement for syringes used for liquid medications and vaccines (see my Dec. 16, 2016 posting for a description).

Silky smooth tissue engineering

Leave a reply

Virginia Commonwealth University (VCU) researchers have announced a new technique for tissue engineering that utilizes silk proteins. From a May 13, 2014 news item on Nanowerk,

When most people think of silk, the idea of a shimmering, silk scarf, or luxurious gown comes to mind.

But few realize, in its raw form, this seemingly delicate fiber is actually one of the strongest natural materials around – often compared to steel.

Silk, made up of the proteins fibroin and sericin, comes from the silkworm, and has been used in textiles and medical applications for thousands of years. The [US] Food and Drug Administration has classified silk as an approved biomaterial because it is nontoxic, biodegradable and biocompatible.

Those very properties make it an attractive candidate for use in widespread applications in tissue engineering. One day, silk could be an exciting route to create environmentally sound devices called “green devices,” instead of using plastics. However, forming complex architectures at the microscale or smaller, using silk proteins and other biomaterials has been a challenge for materials experts.

Now, a team of researchers from the Virginia Commonwealth University School of Engineering has found a way to fabricate precise, biocompatible architectures of silk proteins at the microscale.

A May 12, 2014 VCU news release by Sathya Achia Abraham, which originated the news item, describes the research underlying two recently published papers by the research team

    Kurland [Nicholas Kurland, Ph.D.] and Yadavalli [Vamsi Yadavalli, Ph.D., associate professor of chemical and life science engineering] successfully combined silk proteins with the technique of photolithography in a process they term “silk protein lithography” (SPL). Photolithography, or “writing using light,” is the method used to form circuits used in computers and smartphones, Yadavalli said.

According to Yadavalli, SPL begins by extracting the two main proteins from silk cocoons. These proteins are chemically modified to render them photoactive, and coated on glass or silicon surfaces as a thin film. As ultraviolet light passes through a stencil-like patterned mask, it crosslinks light-exposed proteins, turning them from liquid to solid.

The protein in unexposed areas is washed away, leaving behind patterns controllable to 1 micrometer. In comparison, a single human hair is 80-100 micrometers in diameter.

“These protein structures are high strength and excellent at guiding cell adhesion, providing precise spatial control of cells,” Yadavalli said.

“One day, we can envision implantable bioelectronic devices or tissue scaffolds that can safely disappear once they perform their intended function,” he said.

The team’s current research focuses on combining the photoreactive material with techniques such as rapid prototyping, and developing flexible bioelectronic scaffolds.

Study collaborators included S.C. Kundu, Ph.D., professor of biotechnology at the Indian Institute of Technology Kharagpur in India, and Tuli Dey, Ph.D., postdoctoral associate, at the Indian Institute of Technology Kharagpur in India, who provided the silk cocoons used in the study and assisted with cell culture experiments. VCU has recently filed a patent on this work.

Here’s a link to and a citation for both papers,

Silk Protein Lithography as a Route to Fabricate Sericin Microarchitectures by Nicholas E. Kurland, Tuli Dey, Congzhou Wang, Subhas C. Kundu and Vamsi K. Yadavalli. Article first published online: 16 APR 2014 DOI: 10.1002/adma.201400777

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Precise Patterning of Silk Microstructures Using Photolithography by Nicholas E. Kurland, Tuli Dey, Subhas C. Kundu, and Vamsi K. Yadavalli. Advanced Materials Volume 25, Issue 43, pages 6207–6212, November 20, 2013 Article first published online: 20 AUG 2013 DOI: 10.1002/adma.201302823

© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Both papers are behind a paywall.

I have written about silk proteins in a Nov. 28, 2012 post (Producing stronger silk musically) that briefly mentioned tissue engineering with regard to a new technique for biosynthesising  materials.