Intercalation-FRET Biosensor with a Helical Conjugated Polyelectrolyte

Abstract

A biotin-tetramethylrhodamine (biotin-TMR) quencher-ligand interacts with a (phenylene-ethynylene) based helical conjugated polyelectrolyte (poly-1) via intercalation of the TMR unit into the helix. The interaction is signaled by efficient fluorescence resonance energy transfer (FRET) from the polymer to the TMR chromophore. Avidin addition to the poly-1/biotin-TMR intercalation complex does not interrupt FRET, instead resulting in the formation of avidin-biotin "cross-links". Mixing of biotin-TMR with avidin prior to addition of the polymer efficiently disrupts the FRET signal, giving rise to a sensor with a detection limit of 100 pM for avidin. Study of the FRET response as a function of biotin-TMR and avidin concentration affords insight into the interaction of the protein with the poly-1/biotin-TMR intercalation complex.

Hydrochromic conjugated polymers for human sweat pore mapping

“…Among stimulus-responsive colorimetric substances investigated thus far, conjugated polymers7 have gained special attention owing to their unique optical properties associated with the presence of extensively delocalized π-electron networks. As localized stimulation of conjugated polymers brings about changes in absorption and emission characteristics, these materials have been effectively utilized as sensor matrices891011121314151617.…”

Thermal-induced Immuno-nephelometry Using Gold Nanoparticles Conjugated with a Thermoresponsive Polymer for the Detection of Avidin

“…[9][10][11][12] Positively charged thermoresponsive gold nanoconjugates that contain biotin groups formed a ternary complex with anionic biotinylated poly(acrylate) via avidin. Because the positive and negative charges were spatially isolated in the ternary complex, the complex remained soluble above the phase-transition temperature.…”

Modulation of Charge Density of Cationic Conjugated Polyelectrolytes for Improving the FRET‐Induced Sensory Signal with Enhanced On/Off Ratio

“…Fluorescence resonance energy transfer (FRET) is often used in the CPE‐based sensory system to improve the sensitivity with signal amplification, taking advantage of the high efficiency of long range energy transfer and the large Stokes shift . For example, Bazan and co‐workers reported an in situ CPE‐based DNA detection scheme, where the electrostatic complexation between the cationic CPEs and chromophore‐labeled peptide nucleic acid (PNA‐C) hybridized with a target DNA brings them into close proximity, resulting in efficient FRET from the blue emitting CPEs to a green emitting chromophore in PNA‐C .…”

“…[6][7][8][9][10][11][12] Fluorescence resonance energy transfer (FRET) is often used in the CPE-based sensory system to improve the sensitivity with signal amplifi cation, taking advantage of the high effi ciency of long range energy transfer and the large Stokes shift. [13][14][15][16] For example, Bazan and coworkers reported an in situ CPE-based DNA detection scheme, where the electrostatic complexation between the cationic CPEs and chromophore-labeled peptide nucleic acid (PNA-C) hybridized with a target DNA brings them into close proximity, resulting in effi cient FRET from the blue emitting CPEs to a green emitting chromophore in PNA-C. [ 17,18 ] In the absence of the target DNA, negligible FRET emission was observed due to the large separation between the cationic CPEs and neutral PNA-C. The amplifi ed FRET-induced fl uorophore emission can differentiate the presence and absence of the target DNA with high sensitivity.…”