PEG has been an important type of hydrophilic polymers for biomedical applications, including surface modification, bioconjugation, drug delivery and tissue engineering because they have critical properties, such as good biocompatibility, non-immunogenity, and resistance to protein adsorption [13,14].
Table of Contents
What is PEG hydrogel?
Polyethylene glycol (PEG) hydrogels are widely used in a variety of biomedical applications, including matrices for controlled release of biomolecules and scaffolds for regenerative medicine.
How are PEG hydrogels made?
In order to form a hydrogel, PEG must be cross-linked. Initially, PEG was cross-linked non-specifically using ionizing radiation. PEG hydrogels are now typically synthesized via covalent cross-linking of PEG macromers with reactive chain ends.
Is PEG a biomaterial?
PEG is highly biocompatible and well-suited for use in hydrogels for biological studies. Its repeating alkane-ether motif makes PEG not only very hydrophilic, which is important for nutrient and waste transport, but also biochemically inert.
What is the function of PEG?
PEG (polyethylene glycol) have been widely used in the synthesis of nanomaterials due to its special structure and performance. In this paper, the role PEG played in the preparation of nanomaterials, such as dispersion and stabilization, structure-directing, modification and functionalization were summarized.
Why is PEG used in drug delivery?
Polyethylene glycol (PEG) is widely utilized in drug delivery and nanotechnology due to its reported “stealth” properties and biocompatibility. It is generally thought that PEGylation allows particulate delivery systems and biomaterials to evade the immune system and thereby prolong circulation lifetimes.
Is PEG biodegradable?
Many synthetic biomaterials, including the widely applied polyethylene glycol (PEG) and essentially all polymers derived from radical polymerization reactions comprising a CeC polymer backbone are considered non-biodegradable.
Does hydrogel dissolve in water?
A hydrogel is a crosslinked hydrophilic polymer that does not dissolve in water. They are highly absorbent yet maintain well defined structures. These properties underpin several applications, especially in the biomedical area.
Is ethylene glycol natural or synthetic?
Ethylene glycol is a synthetic liquid substance that absorbs water. It is odorless, but has a sweet taste. Ethylene glycol is used to make antifreeze and de-icing solutions for cars, airplanes, and boats.
How hydrogel is produced?
Hydrogels can be obtained by radiation technique in a few ways, including irradiation of solid polymer, monomer (in bulk or in solution), or aqueous solution of polymer. The first method, i.e., irradiation of hydrophilic polymer in a dry form [64], has some drawbacks.
Which crosslinking method generates very strong hydrogels?
The strategy of hydrophobic crosslinking with macromolecular microspheres has been further utilized to construct a second network interpenetrating to the first network, resulting in double network hydrogels with excellent fracture strength and toughness.
What are the advantages of hydrogels?
Advantages of Hydrogels The main advantage of hydrogel is that they possess a degree of flexibility very similar to natural tissue, due to their significant water content. They are biocompatible, biodegradable and can be injected. Hydrogels also possess good transport properties and easy to modify.
What is PEG in biology?
PEG is the common abbreviation for polyethylene glycol โ or, more properly, poly(ethylene glycol) โ which refers to a chemical compound composed of repeating ethylene glycol units.
What is the difference between PEO and PEG?
The polyethylene oxides (PEO) are available in high molecular weights, while the polyethylene glycols (PEG) cover the lower molecular weight range. The two types are chemically similar so they can be used together across a wider molecular weight range, with aqueous and organic polymers from 106-1 million MW.
How is PEG synthesized?
PEGs are synthesized using a ring-opening polymerization of ethylene oxide to produce a broad range of molecular weights and molecular weight distributions (polydispersity); however, discrete PEGs (dPEGยฎ reagents) are synthesized with a single, specific molecular weight.
Why is PEG hydrophilic?
Poly(propylene glycol) is much less hydrophilic, and this leads to variety of PEG-PPG polymeric surfactants. All PEGs are not hydrophobicity materials. PEG is poly ether, a lot of ether oxygen make it hydrophilic!!! The hydrogen bonding makes PEG hydrophilic, I think.
What products contain PEG?
Polyethylene glycol (PEG) is found in many skin creams, lotions, soaps, hair products and shower gels. PEGs are petroleum-based compound that are often used as thickeners, solvents, softeners, and moisture-carriers.
What is PEG made of?
Polyethylene glycols (PEGs) are composed of polyether compounds repeating ethylene glycol units according to the constituent monomer or parent molecule (as ethylene glycol, ethylene oxide, or oxyethylene) (Fig. 1).
What is PEG biotechnology?
Abstract. Chemical modification of proteins and other bioactive molecules with polyethylene glycol (PEG) or its derivatives (PM) can be used to tailor molecular properties to particular applications, eliminating disadvantageous properties or conferring new molecular functions.
What are the disadvantages of polyethylene glycol?
The available data manifests that polyethylene glycol (PEG) itself shows potential risk, such as immunogenicity of the PEG and PEG-containing vacuoles in cells observed with PEGylated biologicals. Decreased activity and heterogeneity are also the negative aspects of PEGylation.
Is polyethylene glycol the same as ethylene glycol?
Ethylene glycol is a syrupy liquid at room temperature whereas polyethylene glycol is a solid material. The main difference between ethylene glycol and polyethylene glycol is that ethylene glycol has a fixed value for molecular weight whereas polyethylene glycol has no fixed value for molecular weight.
Can bacteria grow in glycol?
At very low glycol concentrations, for example below 1%, both Ethylene and Propylene Glycol act as a nutrient for bacteria. At these concentrations, bacteria will biodegrade the Propylene Glycol causing rapid growth of bacterial contamination.
Is PEG water soluble?
PEG is soluble in water (100 mg/ml), yielding a clear, colorless solution. PEGs are also soluble in many polar solvents such as acetone, alcohols, and chlorinated solvents.
How do you degrade polyethylene glycol?
A model for the degradation of polyethylene glycol (PEG) is presented. Heating to 70 ยฐC in a current of air leads to formation of formic acid. Under dry conditions this reacts with the terminal hydroxyl group of the polyethylene glycol, resulting in formic acid esters.
What is the difference between gel and hydrogel?
Gels are materials composed of a three-dimensional crosslinked polymer or colloidal network immersed in a fluid. They are usually soft and weak, but can be made hard and tough. Hydrogels are gels that have water as their main constituent.