A pollen-primarily based ink opens doorways for developments in 3D bioprinting.
Image credit rating: Srinivas Sudagani Unsplash
Experts have not too long ago found a way to use sunflower pollen to develop a new ink for 3D printing that could be made use of to fabricate areas beneficial for tissue engineering, toxicity tests, and drug delivery.
“Utilizing pollen for 3D printing is a major accomplishment as the course of action of creating the pollen-dependent ink is sustainable and cost-effective,” stated contributor Professor Cho Nam-Joon of the Nanyang Technological University, Singapore (NTU) Faculty of Components Sciences and Engineering. “Given that there are many sorts of pollen species with distinctive dimensions, shapes, and floor qualities, pollen microgel suspensions could possibly be employed to produce a new course of eco-welcoming 3D printing products.”
Now, the most widely used bioprinting process is a technique identified as extrusion-dependent bioprinting, in which inks are dispensed consistently from nozzles and deposited together digitally defined paths to fabricate 3D constructions layer by layer. One of the problems of this approach is the problem in retaining the structures and styles of tender and delicate supplies, this sort of as hydrogels, cells, and biopolymers, devoid of more help.
“Bioprinting can be challenging mainly because the inks utilized is normally far too soft, which suggests the construction of the envisioned product or service might collapse during printing,” additional Nam-Joon. Frequently, a supporting matrix, into which the comfortable ink is deposited throughout the printing process, is ordinarily applied. Nevertheless, this makes squander because the supporting matrix gets to be unusable soon after printing.
But the new ink is capable to maintain its possess condition when deposited onto a surface area, building it an interesting and viable alternate, specifically when it arrives to programs in drugs. “Through tuning the mechanical qualities of sunflower pollen, we made a hybrid ink that can be utilised to print constructions with excellent structural integrity,” reported Nam-Joon.
Applications in biomedicine and tissue engineering
To make their pollen-dependent hybrid ink, the researchers incubate sunflower pollen in an alkaline (primary) solution — an environmentally-friendly process equivalent to soapmaking — for 6 several hours to variety pollen microgel particles. The pollen microgel is then combined with hydrogels, these types of as a polymer referred to as alginate, commonly attained from brown seaweed, or hyaluronic acid, a distinct, gooey substance developed by the body.
They then printed a five-layer tissue engineering scaffold — applied to culturing cells — in just 12 minutes. Collagen was then extra to the scaffold to provide anchor details that cells can adhere to and improve. The experts then seeded human cells on the scaffold and located it to have a higher cell-seeding efficiency of 96-97%. This is similar performance to the inverted colloidal crystal (ICC) hydrogels that are commonly used as 3D mobile tradition platforms but that are time-consuming and laborious to fabricate.
“Our findings could open new doorways to customized versatile membranes that suit the human skin’s contours just, such as wound dressing patches or facial masks,” defined Professor Song Juha from the NTU College of Chemical and Biomedical Engineering. “Such soft and versatile membranes are typically created centered on flat geometry, so resulting in issues these kinds of as fractures in the layers or a bad match when utilized on substantial floor places of pores and skin, these kinds of as the facial area or areas that see regular motion like the joints.”
Recyclable help matrix
The scientists also observed that that the soft and adaptable pollen microgel particles could serve as a recyclable assist matrix for use in freeform 3D printing. To test the feasibility of their technique, they fabricated a 3D-printed silicon rubber mesh for the elbow employing pollen microgel as the guidance that would retain the elbow mesh’s form as it is staying printed.
Right after curing the printed item at 75°C (167°F) for 24 hrs inside of the pollen microgel, the printed 3D-silicone rubber mesh could adapt to the human elbow curvature. They also uncovered that the mechanical houses of the silicone rubber samples printed and remedied in the pollen supporting matrix had been equivalent to those of samples fabricated by way of the common casting system.
“There is also likely for the pollen-centered scaffold to be used as a clever drug carrier, presented pollen’s stimulus-responsive character,” reported Nam-Joon. “For occasion, we can more sluggish down the release of drugs by coating the pollen-dependent scaffold with a thin layer of alginate, and encourage the launch by introducing an acid.”
Presented that pollen responds to pH improvements, the crew also examined the viability of the 3D scaffold as a stimulus-responsive drug shipping system. When a fluorescent crimson dye was dripped onto the scaffold, the pollen microgel particles launched the dye into the scaffold little by little. The amount and price of launch increased with the addition of an acid, demonstrating their use as a drug shipping process with controlled release.
“Pollen microgel particles have a hollow shell framework, which indicates they could likely be made use of to carry prescription drugs, cells, or biomolecules in drug shipping and delivery platforms with customised 3D structures,” claimed Nam-Joon. “We are now hunting at how we can use these pollen microgel scaffolds for 3D cell lifestyle platforms in various biomedical applications.”
The use of pollen in the biomedical subject builds on the NTU study team’s human body of operate on repurposing pollen grains, a all-natural renewable resource, into a building block for many eco-friendly alternate products, from eco-pleasant paper to biodegradable sponges that can soak up oil pollutants.
The workforce is now hunting to collaborate with sector to refine their 3D printing innovation and progress its commercial uptake.
Reference: Shengyang Chen, et al., Engineering All-natural Pollen Grains as Multifunctional 3D Printing Materials, Superior Purposeful Materials (2021). DOI: 10.1002/adfm.202106276