Small-molecule Polyethylene Glycol

What is Small-molecule Polyethylene Glycol?

Small-molecule polyethylene glycol (PEG) refers to PEG compounds with low molecular weights (typically below 10,000 Da). When used as small molecules, PEGs can offer unique advantages in different fields, and can be used to modify various types of biological drugs, forming formulation materials through positively ionized lipophilic liposome nanoparticles, which will make it possible to instantly load targeted molecules and achieve mounting of any drug, and can provide proven technical support for building personalized therapeutic drug libraries for oncology patients.

Fig. 1. Structure of poly(ethylene glycol) (Theranostics. 10(7): 3064-3082).

Examples of Small Molecule Polyethylene Glycols

HO-PEG5-OH

HO-PEG5-OH is a small molecule PEG with 5 glycol units, which can be used as versatile polymer chain segments for modulating the solubility, stability, and bioavailability of drugs, or as plasticizers, lubricants, or modifiers of materials.

Hexaethylene Glycol

Hexaethylene glycol is part of jasmine leaf extract and has antioxidant, antibacterial and anticancer properties. It also shows potential application as a functional hydraulic fluid.

Dodecaethylene Glycol

Dodecaethylene glycol has a long glycol chain containing 12 glycol units. It can be used in the preparation of certain surfactants, colloidal systems and drug delivery systems, among others.

Modification of Small Molecule PEG

Depending on the nature of the reaction between the modifier and the modified compound, the modification reaction is mainly classified into the types of acylation reaction, alkylation reaction, redox reaction, aromatic ring substitution reaction, etc., which chemically modifies the modified compound with the side-chain groups such as amino group, sulfhydryl group and carboxyl group. Depending on the molecular weight, molecular structure, and physical and chemical properties of the modified compounds, including proteins, peptides, monoclonal antibody molecular fragments, and small molecule compounds, different PEGylation techniques are used to modify these compounds.

How to Activate Small Molecule PEG?

The connection between small molecule PEG and other compounds is mainly through the terminal hydroxyl group of PEG, such as amino acid residues. However, the terminal hydroxyl group of PEG is very inactive and it is difficult to couple with other groups in a mild environment, so an activator is needed to activate the hydroxyl group. Activated PEG can covalently modify the modified substance in a mild environment. Methods of activation include: cyanogen bromide method, carbonyl diimidazole method, cyanuric chloride method, and PEG structure modification method.

Application of Small Molecule PEG

• Protein Precipitation: By adding appropriate amount of PEG (PEGylation of Proteins) and salt to the solution, the protein can be precipitated, thus realizing the separation and enrichment of protein.
• Cell Fusion: By adding PEG to two cell populations, cells can be induced to fuse and form hybrid cells. This is useful in areas such as cell research, antibody production and bioengineering.
• DNA or RNA Precipitation: By adding PEG to a DNA or RNA solution (PEGylation of Nucleic Acids), nucleic acids can be precipitated out, thereby removing impurities and purifying the target molecule.
• Protein Crystallization: The use of small molecule PEGs as co-solvents can provide the right solution conditions to facilitate protein crystallization and improve the quality and growth rate of crystals.
• Cell Protection and Freezing: Small molecule PEG has the ability to protect cells from damage during freezing and thawing. Mixing cells with appropriate concentrations of PEG during cell cryopreservation provides osmotic protection and reduces freezing-induced cell damage.
• Stabilizers for Antibodies and Enzymes: Small molecule PEG can be used as stabilizers for antibodies and enzymes, prolonging their activity during storage and use.

BOC Sciences provides high quality small molecule PEG products based on expertise and experience, if you are interested in our products, please feel free to contact us.

Reference

1. Wu, D. et al. An EPR Strategy for Bio-responsive Fluorescence Guided Surgery with Simulation of the Benefit for Imaging. Theranostics. 10(7): 3064-3082.