Editing Biopolymer (section)

== Common biopolymers ==
'''Collagen''':<ref name="Yadav-2015">{{Cite journal |last=Yadav |first=P. |last2=Yadav |first2=H. |last3=Shah |first3=V. G. |last4=Shah |first4=G. |last5=Dhaka |first5=G. |year=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 |pmc=4606363 |pmid=26501034}}</ref> [[Collagen]] is the primary structure of vertebrates and is the most abundant protein in mammals. Because of this, collagen is one of the most easily attainable biopolymers, and used for many research purposes. Because of its mechanical structure, collagen has high tensile strength and is a non-toxic, easily absorbable, biodegradable, and biocompatible material. Therefore, it has been used for many medical applications such as in treatment for tissue infection, drug delivery systems, and gene therapy.

'''Silk fibroin''':<ref>{{Cite journal |last=Khan |first=Md. Majibur Rahman |last2=Gotoh |first2=Yasuo |last3=Morikawa |first3=Hideaki |last4=Miura |first4=Mikihiko |last5=Fujimori |first5=Yoshie |last6=Nagura |first6=Masanobu |date=2007-04-01 |title=Carbon fiber from natural biopolymer Bombyx mori silk fibroin with iodine treatment |url=https://soar-ir.repo.nii.ac.jp/record/13561/files/Carbon_fiber_from_Bombyx_mori.pdf |url-status=live |journal=Carbon |language=en |volume=45 |issue=5 |pages=1035–1042 |bibcode=2007Carbo..45.1035K |doi=10.1016/j.carbon.2006.12.015 |issn=0008-6223 |s2cid=137350796 |archive-url=https://web.archive.org/web/20210715171521/https://soar-ir.repo.nii.ac.jp/record/13561/files/Carbon_fiber_from_Bombyx_mori.pdf |archive-date=2021-07-15 |hdl-access=free |hdl=10091/263}}</ref> [[Silk fibroin|Silk Fibroin]] (SF) is another protein rich biopolymer that can be obtained from different silkworm species, such as the mulberry worm Bombyx mori. In contrast to collagen, SF has a lower tensile strength but has strong adhesive properties due to its insoluble and fibrous protein composition. In recent studies, silk fibroin has been found to possess anticoagulation properties and platelet adhesion. Silk fibroin has been additionally found to support stem cell proliferation in vitro.

'''Gelatin''': [[Gelatin]] is obtained from type I collagen consisting of cysteine, and produced by the partial hydrolysis of collagen from bones, tissues and skin of animals.<ref name="Mohan-2016">{{Cite journal |last=Mohan |first=Sneha |last2=Oluwafemi |first2=Oluwatobi S. |last3=Kalarikkal |first3=Nandakumar |last4=Thomas |first4=Sabu |last5=Songca |first5=Sandile P. |date=2016-03-09 |title=Biopolymers – Application in Nanoscience and Nanotechnology |url=https://www.intechopen.com/books/recent-advances-in-biopolymers/biopolymers-application-in-nanoscience-and-nanotechnology |journal=Recent Advances in Biopolymers |language=en |doi=10.5772/62225 |isbn=978-953-51-4613-1 |doi-access=free}}</ref> There are two types of gelatin, Type A and Type B. Type A collagen is derived by acid hydrolysis of collagen and has 18.5% nitrogen. Type B is derived by alkaline hydrolysis containing 18% nitrogen and no amide groups. Elevated temperatures cause the gelatin to melts and exists as coils, whereas lower temperatures result in coil to helix transformation. Gelatin contains many functional groups like NH2, SH, and COOH which allow for gelatin to be modified using [[nanoparticle]]s and biomolecules. Gelatin is an Extracellular Matrix protein which allows it to be applied for applications such as wound dressings, drug delivery and gene transfection.<ref name="Mohan-2016" />

'''Starch:''' [[Starch]] is an inexpensive biodegradable biopolymer and copious in supply. Nanofibers and [[microfiber]]s can be added to the polymer [[wikt:matrix|matrix]] to increase the mechanical properties of starch improving [[Elasticity (physics)|elasticity]] and strength. Without the fibers, starch has poor mechanical properties due to its sensitivity to moisture. Starch being biodegradable and renewable is used for many applications including plastics and pharmaceutical tablets.{{cn|date=January 2025}}

'''Cellulose:''' [[Cellulose]] is very structured with stacked chains that result in stability and strength. The strength and stability comes from the straighter shape of cellulose caused by glucose [[monomer]]s joined by glycogen{{cn|date=April 2025}} bonds. The straight shape allows the molecules to pack closely. Cellulose is very common in application due to its abundant supply, its biocompatibility, and is environmentally friendly. Cellulose is used vastly in the form of nano-fibrils called nano-cellulose. Nano-cellulose presented at low concentrations produces a transparent gel material. This material can be used for biodegradable, [[Homogeneous and heterogeneous mixtures|homogeneous]], dense films that are very useful in the biomedical field.<ref>{{Cite journal |last=Meshram |first=Bhushan P. |last2=Jain |first2=Prachi |last3=Gaikwad |first3=Kirtiraj K. |date=2025-02-21 |title=Innovative Development of Kodo Millet (Paspalum scrobiculatum)-Based Functional Edible Cups Modified with Hibiscus Powder and Guar Gum: An Eco-Efficient Resource Utilization |url=https://pubs.acs.org/doi/10.1021/acsfoodscitech.4c00985 |journal=ACS Food Science & Technology |volume=5 |issue=2 |pages=788–799 |doi=10.1021/acsfoodscitech.4c00985}}</ref>

'''Alginate:''' [[Alginate]] is the most copious marine natural polymer derived from brown seaweed. Alginate biopolymer applications range from packaging, textile and food industry to biomedical and chemical engineering. The first ever application of alginate was in the form of wound dressing, where its gel-like and absorbent properties were discovered. When applied to wounds, alginate produces a protective gel layer that is optimal for healing and tissue regeneration, and keeps a stable temperature environment. Additionally, there have been developments with alginate as a drug delivery medium, as drug release rate can easily be manipulated due to a variety of alginate densities and fibrous composition.