Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-02T22:45:15.752Z Has data issue: false hasContentIssue false

Water-Soluble Conjugated Polyelectrolytes with Molecular Bumper for Efficient FRET Biosensor

Published online by Cambridge University Press:  26 February 2011

Han Young Woo
Affiliation:
[email protected], Pusan National University, Nanomaterials Engineering, 30 Jangjeon-dong, Geumjeong-gu, Busan, 609-735, Korea, Republic of
Doojin Vak
Affiliation:
[email protected], Institute for Polymers and Organic Solids, UCSB, Chemistry, Santa Barbara, CA, 93106, United States
Guillermo C Bazan
Affiliation:
[email protected], Institute for Polymers and Organic Solids, UCSB, Chemistry, Santa Barbara, CA, 93106, United States
Get access

Abstract

We report the design, synthesis and photophysical properties of two new water-soluble conjugated polyelectrolytes, poly(9,9'-bis(6-N,N,N-trimethylammoniumhexyl)fluorene-alt-1,4-(2,5-bis(6-N,N,N-trimethylammoniumhexyloxy))phenylene) tetrabromide (P1i) and poly((10,10'-bis(6-N,N,N-trimethylammoniumhexyl)-10H-spiro(anthracene-9,9'-fluorene))-alt-1,4-(2,5-bis(6-N,N,N-trimethylammoniumhexyloxy))phenylene) tetrabromide (P2i). They have same electronic conjugation but the main structural difference is the presence of the anthracenyl substituent orthogonal to the polymer main backbone in P2i. Fluorescence resonance energy transfer (FRET) from the two polymers as FRET donors to fluorescein-labeled single stranded DNA (ssDNA-Fl) was studied. It is observed the emission from ssDNA-Fl via FRET by excitation of P2i with a FRET efficiency of ∼60%. Fluorescein is not emissive within the ssDNA-Fl/P1i complex. We also observed clear PL quenching (Φ = 0.8 → Φ = 0.27) of fluorescein for P2i after electrostatic complexation with ssDNA-Fl. It suggests a quenching pathway of Fl emission through photo-induced charge transfer (PCT) in the electrostatic complex. Both P1i and P2i have same HOMO-LUMO electronic structures and a similar thermodynamic driving force for either FRET or PCT. It appears that PCT operates to a larger extent with P1i, proposing that the presence of the “molecular bumper” in P2i increases Fl emission by increasing the donor-acceptor distance, which decreases more acutely PCT quenching, relative to FRET.

Type
Research Article
Copyright
Copyright © Materials Research Society 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. (a) McQuade, D. T., Pullen, A. E. and Swager, T. M., Chem. Rev. 100, 2537 (2000). (b) T. M. Swager, Acc. Chem. Res. 31, 201 (1998).Google Scholar
2. (a) Heeger, P. S. and Heeger, A. J., Proc. Natl. Acad. Sci. USA 96, 2219 (1999). (b) B. Liu and G. C. Bazan, Chem. Mater. 16, 4467 (2004).Google Scholar
3. Gaylord, B. S., Heeger, A. J. and Bazan, G. C., Proc. Natl. Acad. Sci. USA 99, 0954 (2002).Google Scholar
4. Greenham, N. C., Samuel, I. D. W., Hayes, G. R., Phillips, R. T., Kessener, Y. A. R. R., Moratti, S. C., Holmes, A. B. and Friend, R. H., Chem. Phys. Lett. 241, 89 (1995).Google Scholar
5. Vak, D., Chun, C., Lee, C. L., Kim, J.-J. and Kim, D.-Y., J. Mater. Chem. 14, 1342 (2004).Google Scholar
6. Wang, S., Liu, B., Gaylord, B. S. and Bazan, G. C., Adv. Mater. 13, 463 (2003).Google Scholar
7. Torimura, M., Kurata, S., Yamada, K., Yokomaku, T., Kamagata, Y., Kanagawa, T. and Kurane, R., Anal. Sci. 17, 155 (2001).Google Scholar