Photopolymerization-based signal amplification

Photopolymerization-based Signal Amplification

- Process description of photopolymerization based signal amplification diagnostic test

First, a droplet of patient’s sample is loaded on the test strip whose surface is covered with immobilized antibodies. If the sample has target antigens, they bind to immobilized antibodies. Second, eosin-conjugated antibodies are added on the patient’s sample. This second antibodies specifically bind with the bound antigens, thereby causing each bound antigen to be sandwiched between the first antibody and the second antibody with eosin. Third, monomers and phenolphthalein mixture is added on the test strip. Finally, the droplet is illuminated with green visible light to initiate polymerization, by which eosin molecules become excited and produce radicals. As a result, propagation is caused and polymers are formed. Since phenolphthalein molecules are surrounded by the polymers and thus left on the surface even after rinsing the droplet, the test strip turns red with adding base. On the other hand, if the patient’s sample does not include the targeted antigens, the sandwiched binding complexes on the surface will not be formed, which leads to no red color in the end.

(Should be revised based on final draft.)

References

1. Kaastrup et al, Using photo initiated polymerization reactions to detect molecular recognition, 2016

2. Kaastrup et al, Polymerization-based signal amplification under ambient conditions with 35-second reaction times, 2012

3. Miller et al, Addressing Barriers to the Development and Adoption of Rapid Diagnostic Tests in Global Health, 2015

4. Padon et al, The Effect of Oxygen on the Three-Component Radical Photoinitiator System : Methylene Blue, MDEA, and Diphenyliodonium Chloride, 2000

5. Borská et al, Photochemically Induced ATRP of Methacrylates in the Presence of Air : The Effect of Light Intensity, Ligand, and Oxygen Concentration, 2016