AP Biology class blog for discussing current research in Biology

Tag: cellulose

Unlocking Nature’s Secret: Crafting Cellulose Gels by Mimicking Avian Saliva

Researchers at North Carolina State University have harnessed inspiration from the ingenious tactics of small birds’ nest-building processes to develop an eco-friendly and cost-effective method for developing cellulose gels. This freeze-thaw technique is not only straightforward but also holds promise for creating cellulose gels that find application in diverse fields, including the development of timed drug delivery systems. What’s more, this process is suitable to bamboo and other plant fibers containing lignin. Cellulose stands out as a versatile material in the production of hydrogels, indispensable in various applications, from contact lenses to wound care and drug delivery. However, the usual methods for creating hydrogels from cellulose often involve the use of toxic processes. Usually, making cellulose-based hydrogels requires dissolving cellulose and then forming the desired structure. This often involves using difficult, unstable, or unsafe chemicals. As Lucian Lucia, a professor at NC State, points out, “Normally, you have to first dissolve the cellulose and then induce it to crosslink or form the structure of interest, which often requires the use of difficult to handle, unstable, or toxic solvents.”

Little swift, Apus affinis, at Kruger National Park, South Africa, crop

In a stroke of biomimicry, the researchers drew inspiration from the Swift family of birds, known for employing their saliva as a natural adhesive to bind twigs together during nest construction. The saliva encourages the fibers in the nest to interconnect, a phenomenon they sought to replicate with dissolved cellulose for crafting hydrogels. The process involved using water-soluble cellulose, specifically carboxymethyl cellulose (CMC), into an acid solution, which was then dissolved. Powdered cellulose fiber was introduced to the solution, which was then subjected to four rounds of freezing and thawing, resulting in the creation of a cellulose gel. Lucia likened this process to adding a thickening agent to water, akin to thickening a pie filling. By adjusting the CMC’s pH, the water becomes thicker, making it act like glue. The successive freezing and thawing cycles cause the cellulose to compact and interweave, similar to the natural nest-building process of Swifts, but without the need for beaks and saliva. Freeze-drying the gels further led to the production of cellulose foam. The researchers successfully replicated this process using bamboo fibers, suggesting its potential applicability to a wide range of lignin and cellulose-containing fibers. These cellulose gels exhibit resilience and stability at room temperature and can be altered to degrade as needed, making them well-suited for a range of applications, including drug delivery. This approach offers an environmentally friendly means of processing otherwise insoluble cellulosic materials, harnessing the principles of biomimicry. This research has been documented in the journal Advanced Composites and Hybrid Materials, with Noureddine Abidi from Texas Tech University serving as a co-corresponding author. This article on developing eco-friendly cellulose gels using biomimicry in the nest-building process of Swift birds connects to the topics learned in AP Biology. In AP Biology, macromolecules are an essential topic that is studied, and cellulose, the substance examined in the article, is a complex carbohydrate (polysaccharide) that is one of the primary structural components of plant cell walls. It is composed of long chains of glucose molecules that link together to create a tough and rigid structure. This rigid structural integrity of plant cell walls or cellulose is what scientists sought to use to create an adaptable and compatible gel for scientific/medicinal use. After discovering the intriguing properties of cellulose based gels and there potential variety of uses in the medical field, Im left wondering about the potential evolution of cellulose utilization. Did you learn anything new about cellulose and its amazing properties?


Birds Can Teach Us More Than Just Flying

Birds are known for their mostly beautiful, sometimes annoying songs, as well as their super flight abilities, but now, those shouldn’t be the only things they are known for. Scientists have observed the method small birds use to make their nests, as a guide to constructing cellulose gels in a nontoxic way. Scientists use a freeze-thaw process to make the cellulose. This process is modeled after how swift birds (not named after Taylor Swift) spit on the twigs in their nests to hold them together, but also to help connections form between the twigs. Cellulose gel is just a hydrated version of cellulose. Cellulose is the most abundant organic compound on earth. It is a chain of glucose that is different from starches because the glucose is in its beta form. It forms long chains that can build cell walls. It is a major constituent of paper and cotton. Most organisms can not digest cellulose, but inside of us, it acts as soluble fiber that stimulates the digestive tract to secrete mucus to help move feces along.

Cellulose is also a very useful material when it comes to making hydrogels, something that is used in a variety of things in the medical field ranging from contact lenses to wound care. Unfortunately, the process of creating hydrogels is not only difficult but can also be toxic. Normally, you would have to break down the cellulose and then get it to make the crosslink or structure of interest. This process often required the use of toxic, unstable, and/or difficult-to-handle solvents. Knowing how swift birds make their nests, The researchers added a water-soluble cellulose called carboxymethyl cellulose (CMC) to an acid solution and dissolved the CMC. After that, they added powdered cellulose fiber to the solution and put it through four rounds of freezing and thawing. This process generated cellulose gel. Repeatedly freezing and thawing the solution causes the cellulose to compact and intertwine itself into the sticky network. The researchers also did those processes with bamboo fibers and it was a success. This implies that this bird-like freeze-thaw process could be useful with other lignin and cellulose-containing fibers. The cellulose gels are robust, stable at room temperature, and can be tuned to degrade on a schedule, meaning that they’d be very helpful with drug delivery.

Do you think there’s anything else in nature that might hold the key to solving human challenges?

What are some other examples of humans learning from nature?

Little swift, Apus affinis, at Kruger National Park, South Africa, crop

Would you fuel your car with leaves to end global warming?


Leaves are the most abundant product on earth and now can be the answer to end global warming.


Speaking on behalf of my family, we cannot agree on anything! Ironically, we have one tradition that we all agree on. On Sunday evenings, we order take-out food and watch 60 Minutes. Typically, episodes contain a couple segments on current global or domestic political issues, but this past week was different. This past week the last segment was about an unlikely inventor. This inventor was a senile 81 year old man that has quoted himself as the messiah that is here on earth to solve global warming although his drivers license says Marshall Medoff. Mr. Medoff , the unlikely inventor asked  himself, “how do I change inedible plant life into transportation fuels?”


Toiling without an answer, Mr. Medoff went for a stroll around the Walden Pond in the middle of Fall, noticing the vast quantities of leaves and natural debris that covered the ground. Mr. Medoff realized that if he could gain mass quantities of sugar molecules he could solve this issue! When continuing to walk around the pond, Mr. Medoff realized that if he could extract the cellulose from the cell wall of the abundant leaves and natural debree, that he could change the course of history, forever. One may ask, how does this work? It’s simple! In the most basic terms, electron accelerators fire energy downward towards the biomass, breaking the cellulose away from the cell wall, and generating the biofuel.


In reality, I cannot discredit this phenomenal invention as it tackles global warming daily, but we need to take it a step further. This invention will only take roughly thirty to forty percent of the global fossil fuels market and uses only renewable and vastly abundant products. Overarching, this is a phenomenal start, but we as a society are still dependent on fossil fuels, which are depleting quickly. You may ask, SAMonella, What’s next? Personally, I don’t know, but we must continue to invent and create new forms of biofuels and start to become less dependent on fossil fuels. If this trend continues, as a society, we could change the global warming debate for the better! Save the turtles!


Thank you!


From your favorite bacteria,



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