Synthesis and On‐Demand Gelation of Multifunctional Poly(ethylene glycol)‐Based Polymers

Abstract

The synthesis of a novel photoreactive poly(ethylene glycol) (PEG)-based polymer with caged carbonyl groups is reported. We further demonstrate its use for the on-demand fabrication of hydrogels. For rapid gelation, a hydrazide-functionalized PEG is used as the second component for the hydrogel preparation. The photoreactive PEG-based polymer is designed for controlled cleavage of the protecting groups upon exposure to UV light releases free aldehyde moieties, which readily react with hydrazide groups in situ. This hydrogel system may find applications in controlled release drug delivery applications, when combined with in situ gelation. Furthermore, the possibility of forming gels specifically upon UV irradiation gives an opportunity for 3D fabrication of degradable scaffolds.

Extrusion-Based 3D Printing of Poly(ethylene glycol) Diacrylate Hydrogels Containing Positively and Negatively Charged Groups

“…On the other hand, extrusion-based 3D printing offers a relatively quick way to generate 3D structured hydrogel objects in the centimeter range without the need for molds [10,11,12], as used, e.g., in injection molding [13]. Looking at materials used for hydrogel formulations in general, both bio-based polymers like hyaluronic acid [14,15], gelatin [16,17], and alginate [18,19] as well as synthetic polymers like polyacrylamide (PAAm) [20], polyvinyl alcohol (PVA) [21], and poly(ethylene glycol) (PEG) [22,23] have been used in various applications and were partly formulated for extrusion-based 3D printing as well [24,25,26]. In particular, the readily available PEG can be obtained in various polymer architectures and with various end-group functionalities.…”

Using the 3-Diethylaminobenzyl Group as a Photocage in Aqueous Solution

“…We have recently developed a series of structurally simple PPGs for releasing carbonyl, 5−12 hydroxyl, 12−17 diol, 18 carboxyl, 15 and amino groups. 19,20 Their applications in organic synthesis, 21 photoactivated prodrugs, 8,22 photorelease of perfumes in solid phase, 23 photocleavage of polymers, 12 light-controlled hydrogel formation, 24 and surface patterning 25 have been explored recently. These PPGs have advantageous features, including (1) their structural simplicity and chemical stability, (2) simple and cost-effective preparation, (3) high efficiency of protection/deprotection, (4) compatibility with ambient conditions (e.g., air and water) during irradiation, and (5) flexible structural modification without compromising photochemical properties, etc.…”

“…Photolabile protecting groups (PPGs) are protecting groups that can be removed with photoirradiation, which often occurs under mild conditions with precise temporal and spatial control over the course of a reaction. − PPGs have been widely used in biorelated research as “photocages”, and photochemical release of biologically important organic molecules often takes place in aqueous environments. We have recently developed a series of structurally simple PPGs for releasing carbonyl, − hydroxyl, − diol, carboxyl, and amino groups. , Their applications in organic synthesis, photoactivated prodrugs, , photorelease of perfumes in solid phase, photocleavage of polymers, light-controlled hydrogel formation, and surface patterning have been explored recently. These PPGs have advantageous features, including (1) their structural simplicity and chemical stability, (2) simple and cost-effective preparation, (3) high efficiency of protection/deprotection, (4) compatibility with ambient conditions (e.g., air and water) during irradiation, and (5) flexible structural modification without compromising photochemical properties, etc. − ,,, For applications of these PPGs in aqueous solution as photocages, we demonstrated that by incorporating poly­(ethylene glycol) or carboxylate side chains, the PPGs can be converted to their corresponding water-soluble counterpart.…”

Influence of shear thinning and material flow on robotic dispensing of poly(ethylene glycol) diacrylate/poloxamer 407 hydrogels

“…Hydrogels are an interesting class of materials for many applications in the field of biomaterial science, such as tissue engineering, drug delivery, and wound treatments . Additive manufacturing of hydrogels has recently become increasingly interesting due to the availability of suitable materials and devices .…”