Tag Archives: biopolymers

Preprogramming silk protein-based materials

A new material based on silk proteins has been developed at Tufts University (US), according to a Dec. 26, 2016 news item on ScienceDaily,

Tufts University engineers have created a new format of solids made from silk protein that can be preprogrammed with biological, chemical, or optical functions, such as mechanical components that change color with strain, deliver drugs, or respond to light, according to a paper published online this week [Dec. 26 -30, 2016] in Proceedings of the National Academy of Sciences (PNAS).

Caption: This image shows examples of engineered 3-D silk constructs. Credit: Silklab, Department of Biomedical Engineering, School of Engineering, Tufts University

A Dec. 26, 2016 Tufts University news release (also on EurekAlert), which originated the news item, describes the research in more detail,

Using a water-based fabrication method based on protein self-assembly, the researchers generated three-dimensional bulk materials out of silk fibroin, the protein that gives silk its durability. Then they manipulated the bulk materials with water-soluble molecules to create multiple solid forms, from the nano- to the micro-scale, that have embedded, pre-designed functions.

For example, the researchers created a surgical pin that changes color as it nears its mechanical limits and is about to fail, functional screws that can be heated on demand in response to infrared light, and a biocompatible component that enables the sustained release of bioactive agents, such as enzymes.

Although more research is needed, additional applications could include new mechanical components for orthopedics that can be embedded with growth factors or enzymes, a surgical screw that changes color as it reaches its torque limits, hardware such as nuts and bolts that sense and report on the environmental conditions of their surroundings, or household goods that can be remolded or reshaped.

Silk’s unique crystalline structure makes it one of nature’s toughest materials. Fibroin, an insoluble protein found in silk, has a remarkable ability to protect other materials while being fully biocompatible and biodegradable.

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

Programming function into mechanical forms by directed assembly of silk bulk materials by Benedetto Marelli, Nereus Patel, Thomas Duggan, Giovanni Perotto, Elijah Shirman, Chunmei Li, David L. Kaplan, and Fiorenzo G. Omenetto. PNAS 10.1073/pnas.1612063114 December 27, 2016

This paper is behind a paywall.

Future biomedical applications for CNC (cellulose nanocrystals, aka NCC [nanocrystalline cellulose]) from Polytechnic Institute of New York University (NYU-Poly)

It’s good to see a project that might result in applications for CNC (aka, NCC). I commented briefly about the CNC situation earlier today in my Nov. 25, 2013 posting about Lomiko Metals (based in Surrey, BC, Canada) and its focus on developing markets for its product (graphite flakes/graphene). By contrast, Canada’s CelluForce plant (in Québec) has stopped production to avoid adding to its stockpile (as per my Oct. 3, 2013 posting), Alberta has launched a pilot CNC plant (my Nov. 19, 2013 posting), Blue Goose Biorefineries in Saskatchewan was ramping up production according to my May 7, 2013 posting and someone, in a blog posting comment, claimed that Pure Liganin in BC produces CNC (which I cannot confirm since the company mentions neither CNC nor NCC).,

Back to happier matters, a research team from Polytechnic Institute of New York University (NYU-Poly) has discovered information that could be helpful for scientists working with protein polymers (from the Nov. 22, 2013 news item on Azonano,,

A team of researchers has uncovered critical information that could help scientists understand how protein polymers interact with other self-assembling biopolymers. The research helps explain naturally occurring nano-material within cells and could one day lead to engineered bio-composites for drug delivery, artificial tissue, bio-sensing, or cancer diagnosis.

The Nov. 21, 2013 NYU-Poly press release, which originated the news item, goes on to explain the CNC connection to this work,

Bionanocomposites provide a singular area of research that incorporates biology, chemistry, materials science, engineering, and nanotechnology. Medical researchers believe they hold particular promise because—unlike the materials that build today’s medical implants, for example—they are biodegradable and biocompatible, not subject to rejection by the body’s immune defenses. As biocomposites rarely exist isolated from other substances in nature, scientists do not yet understand how they interact with other materials such as lipids, nucleic acids, or other organic materials and on a molecular level. This study, which explored the ways in which protein polymers interact with another biopolymer, cellulose, provides the key to better understanding how biocomposite materials would interact with the human body for medical applications.

The materials analyzed were composed of bioengineered protein polymers and cellulose nanocrystals and hold promise for medical applications including non-toxic, targeted drug delivery systems. [emphasis mine] Such bionanocomposites could also be used as scaffolding for tissue growth, synthetic biomaterials, or an environmentally friendly replacement for petroleum-derived polymers currently in use.

I wonder if the researchers obtained their CNC from the production plant in Wisconsin (US), assuming it has opened since my July 27, 2012 posting featuring an announcement of future plans. Getting back to this latest work, here’s a link to and a citation for the paper,

Bionanocomposites: Differential Effects of Cellulose Nanocrystals on Protein Diblock Copolymers by Jennifer S. Haghpanah, Raymond Tu, Sandra Da Silva, Deng Yan, Silvana Mueller, Christoph Weder, E. Johan Foster, Iulia Sacui, Jeffery W. Gilman, and Jin Kim Montclare. Biomacromolecules, Article ASAP DOI: 10.1021/bm401304w Publication Date (Web): October 18, 2013
Copyright © 2013 American Chemical Society

This paper is behind a paywall.

Offhand I can think of only one Canadian laboratory (although I’m certain there are others), which is working on applications for CNC and that’s Mark MacLaclan’s lab at the University of British Columbia (UBC). For example, there is this ‘in press’ paper,

Shopsowitz, K.E.; Kelly, J.A.; Hamad, W.Y.; MacLachlan, M.J. “Biopolymer Templated Glass with a Twist: Controlling the Chirality, Porosity, and Photonic Properties of Silica with Cellulose Nanocrystals” Adv. Funct. Mater. 2013, in press. DOI: 10.1002/adfm.201301737

You can find more about MacLachlan’s work here.

Nanocellulose as scaffolding for nerve cells

Swedish scientists have announced success with growing nerve cells using nanocellulose as the scaffolding. From the March 19, 2012 news item on Naowerk,

Researchers from Chalmers and the University of Gothenburg have shown that nanocellulose stimulates the formation of neural networks. This is the first step toward creating a three-dimensional model of the brain. Such a model could elevate brain research to totally new levels, with regard to Alzheimer’s disease and Parkinson’s disease, for example.

“This has been a great challenge,” says Paul Gatenholm, Professor of Biopolymer Technology at Chalmers.?Until recently the cells were dying after a while, since we weren’t able to get them to adhere to the scaffold. But after many experiments we discovered a method to get them to attach to the scaffold by making it more positively charged. Now we have a stable method for cultivating nerve cells on nanocellulose.”

When the nerve cells finally attached to the scaffold they began to develop and generate contacts with one another, so-called synapses. A neural network of hundreds of cells was produced. The researchers can now use electrical impulses and chemical signal substances to generate nerve impulses, that spread through the network in much the same way as they do in the brain. They can also study how nerve cells react with other molecules, such as pharmaceuticals.

I found the original March 19, 2012 press release  and an image on the University of Chalmers website,

Nerve cells growing on a three-dimensional nanocellulose scaffold. One of the applications the research group would like to study is destruction of synapses between nerve cells, which is one of the earliest signs of Alzheimer’s disease. Synapses are the connections between nerve cells. In the image, the functioning synapses are yellow and the red spots show where synapses have been destroyed. Illustration: Philip Krantz, Chalmers

This latest research from Gatenholm and his team will be presented at the American Chemical Society annual meeting in San Diego, March 25, 2012.

The research team from Chalmers University and its partners are working on other applications for nanocellulose including one for artificial ears. From the Chalmers University Jan. 22, 2012 press release,

As the first group in the world, researchers from Chalmers will build up body parts using nanocellulose and the body’s own cells. Funding will be from the European network for nanomedicine, EuroNanoMed.

Professor Paul Gatenholm at Chalmers is leading and co-ordinating this European research programme, which will construct an outer ear using nanocellulose and a mixture of the patient’s own cartilage cells and stem cells.

Previously, Paul Gatenholm and his colleagues succeeded, in close co-operation with Sahlgrenska University Hospital, in developing artificial blood vessels using nanocellulose, where small bacteria “spin” the cellulose.

In the new programme , the researchers will build up a three-dimensional nanocellulose network that is an exact copy of the patient’s healthy outer ear and construct an exact mirror image of the ear. It will have sufficient mechanical stability for it to be used as a bioreactor, which means that the patient’s own cartilage and stem cells can be cultivated directly inside the body or on the patient, in this case on the head. [Presumably the patient has one ear that is healthy and the researchers are attempting to repair or replace an unhealthy ear on the other side of the head.]

As for the Swedish perspective on nanocellulose (from the 2010 press release),

Cellulose-based material is of strategic significance to Sweden and materials science is one of Chalmers eight areas of advance. Biopolymers are highly interesting as they are renewable and could be of major significance in the development of future materials.

Further research into using the forest as a resource for new materials is continuing at Chalmers within the new research programme that is being built up with different research groups at Chalmers and Swerea – IVF. The programme is part of the Wallenberg Wood Science Center, which is being run jointly by the Royal Institute of Technology in Stockholm and Chalmers under the leadership of Professor Lars Berglund at the Royal Institute of Technology.

The 2012 press release announcing the work on nerve cells had this about nanocellulose,

Nanocellulose is a material that consists of nanosized cellulose fibers. Typical dimensions are widths of 5 to 20 nanometers and lengths of up to 2,000 nanometers. Nanocellulose can be produced by bacteria that spin a close-meshed structure of cellulose fibers. It can also be isolated from wood pulp through processing in a high-pressure homogenizer.

I last wrote about the Swedes and nanocellulose in a Feb. 15, 2012 posting about recovering it (nanocellulose) from wood-based sludge.

As for anyone interested in the Canadian scene, there is an article by David Manly in the Jan.-Feb. 2012 issue of Canadian Biomass Magazine that focuses largely on economic impacts and value-added products as they pertain to nanocellulose manufacturing production in Canada. You can also search this blog as I have covered the nanocellulose story in Canada and elsewhere as extensively as I can.