Mar 22, 2017 | By Benedict

A team of researchers from the University of Wisconsin-Madison has turned the decellularized husks of plants, such as parsley, vanilla, and orchids, into 3D scaffolds seeded with human stem cells. According to the researchers, the technique offers an alternative to 3D bioprinting biomedical implants.

Human fibroblast cells growing on a parsley husk

In a study that has been published in Advanced Healthcare Materials, a team of biomed experts led by William Murphy, Ph.D., a professor of biomedical engineering and co-director of the UW–Madison Stem Cell and Regenerative Medicine Center, has created a selection of novel biomedical implants. Their resources? Plants, including parsley, vanilla, and orchids. The researchers say these implants could someday be used to repair muscle, organs, and bone.

When making biocompatible implants, sometimes the most effective solution is the most obvious: using materials that are as bio as they come. New biomedical technology developed at UW–Madison takes advantages of the inherent structural qualities of plants, such as strength, rigidity, and porosity, in order to develop effective biomedical implants that could rival those made via bioprinting processes. “Nature provides us with a tremendous reservoir of structures in plants,” said Gianluca Fontana, Ph.D., lead author of the study. “You can pick the structure you want.”

Using natural materials such as those found in plants poses many advantages. However, the most significant in this case was the large surface area provided by the decellularized husks of plants such as parsley, vanilla, and orchids. “Plants are really special materials as they have a very high surface area-to-volume ratio, and their pore structure is uniquely well designed for fluid transport,” said Dr. Murphy.

Human fibroblast cell on a lilac leaf

Selecting the plants they eventually chose was no act of guesswork either. According to the researchers, only a handful of natural substances offered the right properties for the task, and to find these substances they teamed up with Madison's Olbrich Botanical Gardens and its curator John Wirth. In addition to the plants already mentioned, Wirth and the Olbrich team suggested that bamboo, elephant ear plants, and wasabi could all be used to create biomedical scaffolds. Some plants, such as the wetland-loving bulrush, were even collected from the UW-Madison Arboretum.

“The vast diversity in the plant kingdom provides virtually any size and shape of interest,” said Murphy. “It really seemed obvious. Plants are extraordinarily good at cultivating new tissues and organs, and there are thousands of different plant species readily available. They represent a tremendous feedstock of new materials for tissue engineering applications.”

Although plants like parsley, vanilla, orchids, and bamboo have very different properties, the constituent linking them all is cellulose—what the plants’ cell walls are made of. Cellulose is also the vital ingredient in the researchers’ study: after stripping away all of the other cells of the plant and leaving only cellulose, the researchers could treat these cellulose husks with human stem cells such as fibroblasts, which could then attach to and grow on the husks.

Stem of vanilla plant

(Images: Gianluca Fontana / UW-M)

Importantly, these human stem cells appear to align according to the structure of the cellulose husks, keeping them in formation—just like 3D bioprinting does (for a lot for money). "Stem cells are sensitive to topography,” Fontana explained. “It influences how cells grow and how well they grow.” This means that the technique could, if perfected, be used to control the structure and alignment of developing human tissues.

A big advantage of the technique is that these plant husks can be easily altered, cut up, and stacked to suit particular functions. They are also renewable, easy to mass produce, and inexpensive.

The researchers are now planning to conduct tests on animals, which would be the final stage of determining whether the method could be used on humans. “Toxicity is unlikely, but there is potential for immune responses if these plant scaffolds are implanted into a mammal,” said Murphy. “Significant immune responses are less likely in our approach because the plant cells are removed from the scaffolds.”

While 3D bioprinting will not be harmed in any way by the research, the discovery does show that simple solutions can occasionally be as effective as complex ones.

Posted in 3D Printing Technology

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D.L. wrote at 3/22/2017 1:56:00 PM:I am a Biochemist with a love of 3d printing and Bio-engineering. The significance of this breakthrough cannot be overstated. This changes everything. One of the biggest roadblocks for organ development was the speed and cost at which scaffolds could be made. This will drastically speed up the development of those technologies. This also gets around much of the sensitivity issues plaguing other scaffolds. Thank you, this made my day.



