There is a significant focus within the biomedical industry on research into safe, easy to fabricate advanced materials for use in applications such as drug delivery, diagnostic imaging, and tissue engineering. Attractive materials that are gaining interest in the field are starch copolymers, and their use for biomedical applications is the focus of a paper in the journal Carbohydrate Polymers.
Study: Copolymers of starch, a sustainable template for biomedical applications: A review. Image Credit: Igor Petrushenko/Shutterstock.com
Starch: A Perennially Useful Substance
Starch is a useful substance that has been utilized by humans for centuries. The commercial production of starch became highly organized in Europe in the 1500s and it has been used in textiles manufacturing, paper additives, and as an adhesive. Additionally, starch has good nutritional value and is widely used in many world cuisines.
In the European Union, 11 million tons of starch were produced in 2017. 40% of the total starch produced in the EU is used for industrial processes, whilst 60% is used in the food industry.
Starch granules are found in plants and consist of two polyglucans, amylopectin, and amylose. Amylose is linear in nature with a helical structure, whilst amylopectin has a branched structure consisting of multiple short chains of glucose that are connected by glycosidic bonds.
By mass, amylopectin is the main component in naturally occurring starches. Many studies have been carried out on the structure of both natural and genetically modified starches and how the amylose and amylopectin content affect the substance’s mechanical and physical properties.
The ability of starch to augment biodegradation rates has been explored and demonstrated extensively by the plastics industry. Additionally, many products which contain starch composites including biodegradable thin-films and kitchenware are currently commercially available as an alternative to petroleum-derived products.
Starch is a sustainable, environmentally friendly substance. In recent years, it has gained attention for its use in the biomedical industry as a non-toxic, sustainable, high efficacious component in composite materials for a range of applications such as antimicrobial agents, medical imaging, and targeted drug delivery and controlled release systems.
However, despite being eminently useful as an alternative, sustainable material, there are some drawbacks to the substance which hinder its commercial application. Native starch varies structurally between species, is insoluble in water, and has the limitation of breaking down in acidic environments when treated or reheated. Due to these challenges, research has focused on modifying native starch via enzymatic or chemical means to improve its properties.
Some chemical methods that have been explored include grafting copolymers onto the surfaces of native starch. This technique has been shown to improve properties such as hydrophobicity and hydrophilicity, depending on applied conditions and reagents.
Critically Exploring Starch Copolymer Materials for the Biomedical Industry
Using starch copolymers for biomedical applications is highly advantageous. The substance is biodegradable, low-cost, easy to source, and has beneficial effects such as biocompatibility and hydrophobicity. As mentioned, grafting copolymers onto the surface of native starches significantly improves their properties, and the study in Carbohydrate Polymers has critically explored the latest research on using grafting for biomedical applications.
Further Reading: Rapid Visco Analyser (RVA) for Unmodified Dent Corn Starches
In the research, the authors have reviewed current literature on greener synthetic approaches alongside the use of enzymes and analogs in synthesis such as high-performance biocatalysts based on immobilized lipid enzymes on magnetic nanoparticles, and alternative solvents such as ionic liquids and water emulsions.
The authors of the study have pointed out that one major drawback of traditional copolymer grafting methods is their use of toxic, hazardous, and corrosive chemicals. These materials can harm both the environment and human health, making them unsuitable for use in biomedical applications where they may negatively affect the health of patients.
It is proposed that this can be circumvented using non-toxic biocatalysts and “green” solvents. Enzymatic modifications also offer innovative and sustainable modification of grafted starch copolymer materials.
The authors behind the research have stressed that in order to understand this topic better, more research is needed. This includes further studying the relationship between structure and properties in grafted starch copolymers. Understanding this will provide pertinent information on the molecular mechanisms and parameters at play and help achieve the desired synthesis pathways.
By analyzing the current literature and research perspectives on grafted copolymer starches, the study has provided a knowledge base for future research and advances in the field.
The authors have identified significant opportunities for the use of these sustainable, bioactive, non-toxic composite materials in the field of biomedical sciences for applications such as targeted drug delivery and medical imaging. Although challenges still exist, the potential uses of these materials are exciting.
Sarder, R et al. (2021) Copolymers of starch, a sustainable template for biomedical applications: A review [online] Carbohydrate Polymers | sciencedirect.com. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0144861721013606