Using photo-initiated polymerization reactions to detect molecular recognition

Abstract

Widely used medical diagnostic devices and assays that sense the presence of a particular molecule in a bodily fluid often rely on either a nanoparticle label or an enzymatic reaction to generate a signal that is easily detectable. In many cases, it is desirable if the magnitude of the signal correlates with the concentration of the molecule of interest. Photo-initiated polymerization reactions are an alternative means of generating amplified signals that can be used to quantify biological molecules in complex fluids. In this case, the formation of a polymer, typically a cross-linked hydrogel, signifies the presence of the molecule of interest. This tutorial review explains how photo-initiated polymerization reactions have been used in a conditional manner to detect and quantify molecular recognition events. We weigh the advantages and disadvantages of using photo-initiated reactions in comparison with other approaches and highlight exciting directions and opportunities in this area.

Visible Light Cross‐Linking of Gelatin Hydrogels Offers an Enhanced Cell Microenvironment with Improved Light Penetration Depth

“…We hypothesize that the Ru + SPS system has a slower but more sustained radical generation rate being a noncleavage type 2 photo-initiator that undergoes a self-recycling mechanism (Figure 1). [35,39,48,58] It has been previously reported that this ability to re-initiate polymerization allows type 2 photo-initiators to be less affected by oxygen inhibition. [58] Further covalent incorporation of chondrogenic factors or growth factor-binding peptides within Vis + Ru/SPS Gel-MA hydrogels (such as TGF-ß1, hyaluronic acid, heparin) would likely further enhance this chondrogenic niche.…”

“…[35,39,48,58] It has been previously reported that this ability to re-initiate polymerization allows type 2 photo-initiators to be less affected by oxygen inhibition. [58] Further covalent incorporation of chondrogenic factors or growth factor-binding peptides within Vis + Ru/SPS Gel-MA hydrogels (such as TGF-ß1, hyaluronic acid, heparin) would likely further enhance this chondrogenic niche. [12,59] The clinical relevance of these visible light initiating systems are particularly appealing for cell delivery or as spacefillers post augmentation, where in situ photo-curing typically requires high light intensity to minimize both oxygen inhibition and light attenuation.…”

Fabrication of highly efficient ultraviolet absorbing PVDF membranes via surface polydopamine deposition

“…Everything has two sides and UV–vis light is no exception . There were many studies on using high‐energy UV light to initiate reactions and UV light irradiation has become a very important method . However, the loss of mechanical properties, photodegradation, discoloration, and photocrosslinking of polymers can be caused by UV radiation.…”

Cell‐Surface Engineering for Advanced Cell Therapy

“…[143,144] The mechanism, in brief, involves absorption of light by the dye, which then underdoes energy,c harge and/ore lectron and proton transfer with the co-initiator,y ieldingac o-initiatorr adical (i.e., a-aminoalkyl radical) capable of initiating polymerization. [145,146] Ar edox-initiated, radical-mediated polymerization technique for encapsulatingc ells that does not employ al ight source has also been reported. In this technique, free radicals are generated by one-electron transferr eactions in the presence of redox initiators, such as ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TMEDA) (Figure 3e).…”