What is Polyethylene Glycol?
Polyethylene glycol (PEG) is a hydrophilic polymer synthesized by the ring-opening polymerization of ethylene oxide and consists of -(O-CH2-CH2)-repeating units. PEG is a versatile chemical compound that finds extensive applications in the pharmaceutical industry. With its unique properties and ability to modify drug properties, PEG has become an essential ingredient in various pharmaceutical formulations.
Here, Alfa Chemistry mainly introduces the multifunctional applications of PEG in the field of biomedicine, including vaccines, drug delivery and tissue engineering.
Application of PEG in Vaccines
Vaccines play a crucial role in preventing infectious diseases and maintaining public health. Polyethylene glycol has emerged as a valuable component in vaccine formulation due to its biocompatibility and ability to enhance vaccine efficacy. One notable example is the development of lipid nanoparticle-based mRNA vaccines, such as the COVID-19 vaccines.
PEG is used in these mRNA vaccines to encapsulate the genetic material and protect it from degradation. Additionally, PEG helps improve the stability and longevity of the vaccine, ensuring its efficacy during storage and transportation. By incorporating PEG into vaccine formulations, scientists have been able to develop highly effective vaccines against a wide range of pathogens, including viruses, bacteria, and parasites.
Application of PEG in Drug Delivery
Maximizing therapeutic outcomes and minimizing side effects necessitates efficient drug delivery. The field has experienced a revolution with the introduction of polyethylene glycol (PEG) in drug delivery systems. A notable application of PEG in this field is the creation of PEGylated liposomes. These liposomes exhibit biocompatibility, biodegradability, and have the ability to encapsulate a wide range of drugs. The PEG coating on the liposome surface offers various advantages, such as prolonged circulation time, reduced immunogenicity, and improved stability. Consequently, this enables targeted drug delivery to specific areas in the body, resulting in minimized side effects and enhanced efficacy.
Application of PEG in drug delivery. 
Application of PEG in Tissue Engineering
PEG has a unique set of properties that make it suitable for various applications in tissue engineering. For instance, its hydrophilicity and resistance to protein adsorption make it an ideal material for cell encapsulation, as it allows for high cell viability and functionality. For example, YS Kim et al. developed a highly conductive PEG-based hydrogel scaffold. Electro-responsive H9C2 myocytes were cultured on the resulting PEG-based conductive hydrogel to study cell adhesion, proliferation, and cytotoxicity. The results indicate that this PEG-based hydrogel scaffold exhibits potential for future tissue engineering. 
Synthesis of conductive hydrogels. 
How to Choose Polyethylene Glycol?
Choosing the right PEG for different applications usually requires considering factors such as its molecular weight, molecular structure (linear, Y-shaped, multi-arm), reactive groups, and functional groups. The preliminary selection guide for PEG with different molecular weights in drug delivery is shown in the figure below for reference only. 
Various applications of PEG. 
- Anisha A. D'souza, et al. Expert opinion on drug delivery, 2016, 13(9), 1257-1275.
- Kim Y S, et al. Reactive and Functional polymers, 2016, 109, 15-22.
Our products and services are for research use only and cannot be used for any clinical purposes.