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Amphiphilic porphyrins for second harmonic generation imaging
James E Reeve1, Hazel A Collins, Kurt De Mey
1Department of Chemistry, University of Oxford, Chemistry Research Laboratory, UK.
Journal of the American Chemical Society
|February 13, 2009
Summary
Amphiphilic porphyrins with unique structures exhibit high molecular hyperpolarizabilities and bind to biological membranes. These porphyrins enable advanced imaging techniques like second harmonic generation (SHG) microscopy for cellular visualization.
Area of Science:
- Organic Chemistry
- Biophysics
- Materials Science
Background:
- Amphiphilic donor-acceptor porphyrins possess tunable electronic properties.
- High molecular hyperpolarizability is crucial for nonlinear optical applications.
- Biological membrane interactions are key for in vivo imaging.
Purpose of the Study:
- To synthesize and characterize novel amphiphilic donor-acceptor meso-ethynyl porphyrins.
- To investigate the nonlinear optical properties, specifically molecular hyperpolarizability.
- To explore the utility of these porphyrins in second harmonic generation (SHG) microscopy for biological imaging.
Main Methods:
- Synthesis of porphyrin derivatives with pyridinium and dialkyl-aniline groups.
- Hyper-Rayleigh scattering measurements to determine molecular hyperpolarizability.
- Second Harmonic Generation (SHG) microscopy of porphyrins bound to water droplets and cell membranes.
Main Results:
- The synthesized porphyrins demonstrated high molecular hyperpolarizabilities.
- Strong SHG signals were observed at 420 nm from incident light at 840 nm.
- Copper(II) and nickel(II) complexes showed comparable SHG signals without two-photon excited fluorescence.
Conclusions:
- Amphiphilic donor-acceptor porphyrins are promising nonlinear optical materials.
- These porphyrins facilitate effective SHG microscopy for biological applications.
- Metal-substituted porphyrins offer advantages for imaging by avoiding fluorescence interference.
