Editing Biopolymer (section)

== Biopolymer applications ==

The applications of biopolymers can be categorized under two main fields, which differ due to their biomedical and industrial use.<ref name="Applications of Discrete Synthetic" />

=== Biomedical ===
Because one of the main purposes for biomedical engineering is to mimic body parts to sustain normal body functions, due to their biocompatible properties, biopolymers are used vastly for [[tissue engineering]], medical devices and the pharmaceutical industry.<ref name="Yadav-2015" /> Many biopolymers can be used for [[regenerative medicine]], tissue engineering, drug delivery, and overall medical applications due to their mechanical properties. They provide characteristics like wound healing, and catalysis of bioactivity, and non-toxicity.<ref>{{Cite journal |last=Rebelo |first=Rita |last2=Fernandes |first2=Margarida |last3=Fangueiro |first3=Raul |date=2017-01-01 |title=Biopolymers in Medical Implants: A Brief Review |journal=Procedia Engineering |series=3rd International Conference on Natural Fibers: Advanced Materials for a Greener World, ICNF 2017, 21–23 June 2017, Braga, Portugal |language=en |volume=200 |pages=236–243 |doi=10.1016/j.proeng.2017.07.034 |issn=1877-7058 |doi-access=free}}</ref> Compared to synthetic polymers, which can present various disadvantages like immunogenic rejection and toxicity after degradation, many biopolymers are normally better with bodily integration as they also possess more complex structures, similar to the human body.{{citation needed|date=August 2023}}

More specifically, polypeptides like collagen and silk, are biocompatible materials that are being used in ground-breaking research, as these are inexpensive and easily attainable materials. Gelatin polymer is often used on dressing wounds where it acts as an adhesive. Scaffolds and films with gelatin allow for the scaffolds to hold drugs and other nutrients that can be used to supply to a wound for healing.

As collagen is one of the more popular biopolymers used in biomedical science, here are some examples of their use:

'''Collagen based drug delivery systems:''' collagen films act like a [[barrier membrane]] and are used to treat tissue infections like infected corneal tissue or liver cancer.<ref name="Yadav ZE21–ZE25">{{Cite journal |last=Yadav |first=Preeti |last2=Yadav |first2=Harsh |last3=Shah |first3=Veena Gowri |last4=Shah |first4=Gaurav |last5=Dhaka |first5=Gaurav |date=September 2015 |title=Biomedical Biopolymers, their Origin and Evolution in Biomedical Sciences: A Systematic Review |journal=Journal of Clinical and Diagnostic Research |volume=9 |issue=9 |pages=ZE21–ZE25 |doi=10.7860/JCDR/2015/13907.6565 |issn=2249-782X |pmc=4606363 |pmid=26501034}}</ref> Collagen films have all been used for gene delivery carriers which can promote bone formation.

'''Collagen sponges:''' Collagen sponges are used as a dressing to treat burn victims and other serious wounds. Collagen based implants are used for cultured skin cells or drug carriers that are used for burn wounds and replacing skin.<ref name="Yadav ZE21–ZE25" />

'''Collagen as haemostat''': When collagen interacts with [[platelet]]s it causes a rapid coagulation of blood. This rapid coagulation produces a temporary framework so the fibrous stroma can be regenerated by host cells. Collagen based haemostat reduces blood loss in tissues and helps manage bleeding in organs such as the liver and spleen.

[[Chitosan]] is another popular biopolymer in biomedical research.{{according to whom|date=June 2022}} Chitosan is derived from [[chitin]], the main component in the [[exoskeleton]] of crustaceans and insects and the second most abundant biopolymer in the world.<ref name="Yadav-2015" /> Chitosan has many excellent characteristics for biomedical science. Chitosan is biocompatible, it is highly [[Bioactive compound|bioactive]], meaning it stimulates a beneficial response from the body, it can biodegrade which can eliminate a second surgery in implant applications, can form gels and films, and is [[Semipermeable membrane|selectively permeable]]. These properties allow for various biomedical applications of chitosan.

'''Chitosan as drug delivery:''' Chitosan is used mainly with drug targeting because it has potential to improve drug absorption and  stability.  In addition, chitosan conjugated with anticancer agents can also produce better anticancer effects by causing gradual release of free drug into cancerous tissue.<ref>{{Cite journal |last=Bernkop-Schnürch |first=Andreas |last2=Dünnhaupt |first2=Sarah |date=2012 |title=Chitosan-based drug delivery systems |journal=European Journal of Pharmaceutics and Biopharmaceutics |language=en |volume=81 |issue=3 |pages=463–469 |doi=10.1016/j.ejpb.2012.04.007 |pmid=22561955}}</ref>

'''Chitosan as an anti-microbial agent:''' Chitosan is used to stop the growth of [[microorganism]]s. It performs antimicrobial functions in microorganisms like algae, fungi, bacteria, and [[gram-positive bacteria]] of different yeast species.

'''Chitosan composite for tissue engineering:''' Chitosan powder blended with alginate is used to form functional wound dressings. These dressings create a moist, biocompatible environment which aids in the healing process. This wound dressing is also biodegradable and has porous structures that allows cells to grow into the dressing.<ref name="Yadav-2015" /> Furthermore, thiolated chitosans (see [[thiomer]]s) are used for tissue engineering and wound healing, as these biopolymers are able to crosslink via [[disulfide]] bonds forming stable three-dimensional networks.<ref>{{Cite journal |last=Federer |first=C |last2=Kurpiers |first2=M |last3=Bernkop-Schnürch |first3=A |date=2021 |title=Thiolated Chitosans: A Multi-talented Class of Polymers for Various Applications |journal=Biomacromolecules |volume=22 |issue=1 |pages=24–56 |doi=10.1021/acs.biomac.0c00663 |pmc=7805012 |pmid=32567846}}</ref><ref>{{Cite journal |last=Leichner |first=C |last2=Jelkmann |first2=M |last3=Bernkop-Schnürch |first3=A |date=2019 |title=Thiolated polymers: Bioinspired polymers utilizing one of the most important bridging structures in nature |journal=Adv Drug Deliv Rev |volume=151-152 |pages=191–221 |doi=10.1016/j.addr.2019.04.007 |pmid=31028759 |s2cid=135464452}}</ref>

=== Industrial ===
'''Food''': Biopolymers are being used in the food industry for things like packaging, edible encapsulation films and coating foods. Polylactic acid (PLA) is very common in the food industry due to is clear color and resistance to water. However, most polymers have a [[Hydrophilic interaction chromatography|hydrophilic]] nature and start deteriorating when exposed to moisture. Biopolymers are also being used as edible films that encapsulate foods. These films can carry things like [[antioxidant]]s, [[enzyme]]s, [[probiotic]]s, minerals, and vitamins. The food consumed encapsulated with the biopolymer film can supply these things to the body.

'''Packaging:''' The most common biopolymers used in packaging are [[polyhydroxyalkanoates]] (PHAs), [[polylactic acid]] (PLA), and [[starch]]. Starch and PLA are commercially available and biodegradable, making them a common choice for packaging. However, their barrier properties (either moisture-barrier or gas-barrier properties) and thermal properties are not ideal. Hydrophilic polymers are not water resistant and allow water to get through the packaging which can affect the contents of the package. [[Polyglycolic acid]] (PGA) is a biopolymer that has great barrier characteristics and is now being used to correct the barrier obstacles from PLA and starch.

'''Water purification:''' [[Chitosan]] has been used for water purification. It is used as a [[flocculant]] that only takes a few weeks or months rather than years to degrade in the environment. Chitosan purifies water by chelation. This is the process in which binding sites along the polymer chain bind with the metal ions in the water forming [[Chelation|chelates]]. Chitosan has been shown to be an excellent candidate for use in storm and wastewater treatment.<ref>{{Cite journal |last=Desbrières |first=Jacques |last2=Guibal |first2=Eric |date=2018 |title=Chitosan for wastewater treatment |journal=Polymer International |language=en |volume=67 |issue=1 |pages=7–14 |doi=10.1002/pi.5464 |issn=1097-0126 |doi-access=free}}</ref>