Photopolymerization-based signal amplification
Photopolymerization-based Signal Amplification
- Process description of photopolymerization based signal amplification diagnostic test
PBA is achieved by sequentially adding three kinds of solutions to a test strip and illuminating it with green light. First, a droplet of a 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 the immobilized antibodies. Second, eosin-conjugated antibodies are added to the patient’s sample. This second antibody specifically binds with the bound antigens, thereby causing each bound antigen to be sandwiched between the first antibody and the eosin-conjugated antibody. After ten minutes, the droplet on the surface is rinsed away in order to make sure that only the sandwiched binding complexes are left on the surface before adding the third solution.[1]
Lastly, a droplet of monomers and phenolphthalein mixture is added to the test strip, and the droplet is illuminated with green visible light, 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 another rinse, the test strip turns red when a base is added. On the other hand, if the patient’s sample does not include any targeted antigens, the sandwiched binding complexes on the surface will not be formed, which leads to no red color in the end. [1]
References
- ^ a b Kaastrup, K.; Sikes, H. D. (2016-02-01). "Using photo-initiated polymerization reactions to detect molecular recognition". Chem. Soc. Rev. 45 (3): 532–545. doi:10.1039/c5cs00205b. ISSN 1460-4744.
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