title: Tailoring Conformation-Induced Chromism of Polythiophene Copolymers for Nucleic Acid Assay at Resource Limited Settings.
abstract: Here we report on the design and synthesis of cationic water-soluble thiophene copolymers as reporters for colorimetric detection of microRNA (miRNA) in human plasma. Poly(3-alkoxythiophene) (PT) polyelectrolytes with controlled ratios of pendant groups such as triethylamine/1-methyl imidazole were synthesized for optimizing interaction with target miRNA sequence (Tseq). Incorporation of specific peptide nucleic acid (PNA) sequences with the cationic polythiophenes yielded distinguishable responses upon formation of fluorescent PT-PNA-Tseq triplex and weakly fluorescent PT-Tseq duplex, thereby enabling selective detection of target miRNA. Unlike homopolymers of PT (hPT), experimental results indicate the possibility of utilizing copolymers of PT (cPT) with appropriate ratios of pendant groups for miRNA assay in complex matrices such as plasma. As an illustration, colorimetric responses were obtained for lung cancer associated miRNA sequence (mir21) in human plasma, with a detection limit of 10 nM, illustrating the feasibility of proposed methodology for clinical applications without involving sophisticated instrumentation. The described methodology therefore possesses high potential for low-cost nucleic acid assays in resource-limited settings.
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798.
authors.forename: Deepa
authors.initials: D
authors.lastname: Rajwar
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798.
authors.forename: Gopal
authors.initials: G
authors.lastname: Ammanath
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798.
authors.forename: Jamal Ahmed
authors.initials: JA
authors.lastname: Cheema
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798.
authors.forename: Alagappan
authors.initials: A
authors.lastname: Palaniappan
authors.affiliation: Department of Chemistry, Izmir Institute of Technology , Urla, 35430 Izmir, Turkey.
authors.forename: Umit Hakan
authors.initials: UH
authors.lastname: Yildiz
authors.affiliation: School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798.
authors.forename: Bo
authors.initials: B
authors.lastname: Liedberg
mesh_terms: D001483:Base Sequence / Q000235:genetics; D002412:Cations; D003124:Colorimetry; D006801:Humans; D057230:Limit of Detection; D008175:Lung Neoplasms / Q000097:blood* / Q000235:genetics; D035683:MicroRNAs / Q000097:blood* / Q000235:genetics / Q000302:isolation & purification; D020135:Peptide Nucleic Acids / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D002412:Cations; D035683:MicroRNAs; D020135:Peptide Nucleic Acids; D011108:Polymers; D013876:Thiophenes; C066730:polythiophene
keywords: PNA; colorimetric assay; conjugated polyelectrolytes; miRNA; polythiophene