THE EDGE

Tree nanomaterial may help repair and strengthen human bones

BY TONY KRYZANOWSKI

A University of Alberta researcher is hoping to harness the properties of a nanomaterial extracted from trees to help repair and strengthen human bones.

At present, medical science uses inorganic and inert materials such as titanium to substitute for bone structure where it is missing in cases of physical injury, cancer surgery, birth defects and other disease conditions. However, Dr. Reza Vakili is developing a structural material that could give doctors an organic, non-toxic alternative to titanium. A novel, advanced biomaterial called cellulose nanocrystals (CNC) is a critical part of his formulation.

Dr. Reza Vakili (left) is developing an organic replacement for inorganic materials like titanium to repair and replace human bone. The formulation includes cellulose nanocrystals from trees.

Describing his work as “very modern science,” Dr. Vakili says the $182,000 grant from Alberta Innovates through its Alberta Bio Future research and innovation funding program, and the availability of CNC in Alberta from a pilot plant operated by Alberta Innovates, are making his cutting-edge research possible.

Dr. Vakili is a polymer chemist and research associate in the Faculty of Pharmacy and Pharmaceutical Sciences in the field of biomaterials. After attending a workshop about the CNC platform at an Alberta Innovates facility in Edmonton, he came up with the idea of developing a CNC-based organic alternative to materials like titanium for bone repair and replacement. He is working with Dr. Afsaneh Lavasanifar, a Professor of Pharmaceutical Sciences, with research interest in polymer-based delivery systems for drugs and biologics, to develop the entirely new bone repair substance that supports bone growth.

CNC has unique structural, strength and optical properties. The Alberta Innovates CNC pilot plant, one of only a few in the world, is capable of producing several kilograms of high-quality CNC per day from forest biomass.

Dr. Christine Murray, Director of Agricultural Technologies at Alberta Innovates, says Dr. Vakili’s research was chosen for funding under the Alberta Bio Future program because of its many possible benefits.

“CNC is a high-value biomaterial from a natural, renewable resource (trees) available in Alberta. Applications research is required to fully understand and utilize its potential,” says Dr. Murray. “This project was a unique use of CNC, proposing to use its strength properties and biocompatibility in a biomedical situation.”

Moreover, the research supports Alberta’s forest sector and utilizes a leading-edge industrial product being created right in Alberta.

The goal of tissue engineering is to develop “scaffolds” that mimic the structure of healthy tissue. Like scaffolding that supports construction workers, tissue scaffolds can provide strength to bones where some of the structure is missing.

The challenge has been to find a structural material that the body will accept to combine with a soft and porous organic polymer. CNC has proven that it can be used as an organic, non-toxic, strengthening agent to secure the polymer where needed.

What’s exciting about this new approach is that the organic scaffold has both strength and porosity. Doctors are able to implant bone cells onto the porous scaffold. The cells grow and eventually take over the scaffold. Being an organic material, the polymer-CNC scaffold simply dissolves over time, leaving behind actual human bone.

“The focus of research in this area has shifted from development of bio-inert materials as bone replacements toward generation of bio-active materials that can integrate biologics and/or cells for bone regeneration,” says Dr. Vakili.

The potential market for an eventual commercial alternative to materials such as titanium is huge.

“The cost of bone defect repairs has been estimated to be more than $2.5 billion annually just in the U.S. as of 2012. More than half-a-million patients have been treated with bone defect repair techniques,” Vakili says. “This figure is expected to double by 2020 in the United States and globally.”

His research is currently in Phase 1—refining the scaffold formulation. The next step would be to evaluate how well cells grow on the scaffold, followed by clinical testing of the scaffold with live bone to prove its performance. He hopes to have a commercial product available for scale-up in about four years.

For more information about this project, contact Dr. Reza Vakili at [email protected] and for more information about the Alberta Bio Futures funding program, contact [email protected].

CWFC promotes micro-site designs that regenerate high-value and healthy mixedwood forests

BY TONY KRYZANOWSKI

An excavator with a Soukone Meri-crusher high-speed mixer attachment at work (left).

Climate change is having an impact on forest health and will have a definite impact on the forests of the future. So the Canadian Wood Fibre Centre (CWFC) has identified a need to examine options for current reforestation practices by demonstrating a new and innovative approach to establishing micro-sites to ensure that future forests are not only healthy, but bio-diverse and resilient to withstand and flourish in an era of changing climate.

Under its new mandate of helping to maintain forest resource health and sustainability, the CWFC believes that one option to achieve healthy forests in future is to place a greater emphasis on mixedwood reforestation in natural, mixedwood forests, rather than trying to create pure monocultures. Research shows that single species landscapes are among the most vulnerable ecosystems to pests, pathogens, and climate change-induced weather events.

Through its extensive research and experience, CWFC has determined that proper post-harvest micro-site preparation and management is critical to creating an environment for planted tree seedlings or natural regeneration to become well-established and to grow in a harmonized manner. To demonstrate these options, it has established an operational research demonstration site at the Natural Resources Canada Petawawa Research Forest in Ontario and recently participated in a successful two-day tour of the facility for sustainable forest management leaseholders and site prep contractors, which included an equipment and tool demonstration.

CWFC’s approach to successful micro-site design and application is innovative but involves using the same equipment commonly used by logging and site prep contractors with purpose-built tools like the Soukone Meri-crusher high-speed mixer.

Although the research and demonstration site is located in the Great Lakes-St. Lawrence region, CWFC recommends these same innovative micro-site preparation and management techniques for Canada’s extensive mixedwood boreal forest and is sharing this knowledge with site prep contractors working in this environment.

Derek Sidders, CWFC Regional Coordinator and Program Manager, says the key to success is to apply CWFC’s recommended designs and methods with precision. He adds that implementing this approach delivers a number of benefits down the road. These include cost savings realized from increased growth of the seedlings requiring less vegetation management treatments as they mature, and there is the potential to regenerate a variety of commercially-valuable species that result in a healthy, resilient forest.

“We have to address the whole issue of changing climate and opportunities for diversification in how we manage our forests,” says Sidders.

The Petawawa area was a good choice to establish CWFC’s demonstration site because it is situated along the fringe of the area in Canada probably most heavily influenced by a changing climate. The 12-hectare demonstration site was a natural mixedwood forest that had been clearcut as well as another 8-hectare regeneration cut site consisting of white pine, red pine, and hardwoods. The site appeared to already be exhibiting regeneration challenges because of severe drought as well as fluctuating temperature and moisture conditions that were contributing to significant stand mortality.

CWFC Wood Fibre Development Specialist Tim Keddy supervised the establishment of the micro-site demonstration project, with the goal of maintaining its ecosystem integrity by regenerating tree species that were originally in this mixedwood stand.

CWFC used an excavator equipped with a Mericrusher high-speed mixer for selective micro-site preparation. By being selective, it was possible to retain all the residual stems growing on the site. After micro-site preparation, they were planted according to CWFC’s design.

“The excavator with the Meri-crusher high-speed mixer selectively created 1.4 metre wide sites that were usually one or two metres long,” Keddy says. “The idea was to plant trees on the sites so that they were able to establish roots quickly and grow vigorously, while keeping competition at bay for at least two to three years.”

Both softwoods and hardwoods were planted on the micro-sites, with hybrid poplar planted on some sites to re-establish a leaf litter layer to provide organic nutrients. The poplar also acts as a shelter or ‘nurse’ species for some conifers. After 10 to 15 years, they will begin to disappear as the conifer seedlings have become established.

“We’re looking at a different way of managing the forest in the long run,” Keddy says.

For more information about CWFC’s micro-site design and implementation methodology as well as future CWFC-sponsored events, contact Derek Sidders at [email protected] or Tim Keddy at [email protected].