Multiphoton Quantum Dots for Confocal Microscopy and Light Activation

The best of innovative research projects:
      Two photons:
    • Better resolution and penetration
      Quantum Dots:
    • Photochemical stability
    • Extreme brightness
    • Broad excitation spectral range
    • Narrow and symmetric emission spectra
    • Low photobleaching


Biophotonics is the science of generating and harnessing light to image, detect, and manipulate biological materials within the range from individual biomolecules, through cells, to tissue, blood, and whole organs. As an increasingly ageing world population presents new health problems, biophotonics offers great hope for early detection of diseases, new modularities of light-activated therapies, restoring impaired biological functions and tissue engineering. Biophotonic sensors have become of great relevance to the need for non-invasive medical diagnostics and for detection of new strands of microbial organisms and spread of infectious diseases that pose a constant health danger. An important motivation for biophotonics is found in biomedical imaging extending to cells and molecules since most of the understanding about diseases is to be found at this level. Biophotonics thus comprises a wealth of emerging opportunities for medical applications and constitutes a far-reaching vision for future healthcare.

Multiphoton microscopy (MPM)

In biophotonics, multiphoton microscopy (MPM) offers generation of subcellular resolved fluorescence deep into specimens and is generally used for studies of molecular mechanisms for cell-based processes and transgenic models for disease and development. The deep optical penetration, confocality and background reduction in MPM enable aberration-free imaging of fluorescent molecules absorbing in ultraviolet energy regimes with simultaneous imaging of species having very diverse emission spectra. Combined with the development of robust pulsed lasers, these features have made MPM a technically tractable tool to investigate complex biological problems. MPM has, for instance, been applied to live mice for investigating such diverse processes as neuronal dynamics, Alzheimer's plague progression and tumour biology and growth. two-photon
vs. one-photon

Solid state Quantum Dots

Quantum dots (QDs) are nanocrystals of semiconductors that exhibit quantum confinement effects. The emission wavelength of fluorophores using QDs can be tuned by selecting the size of the QD, resulting in a wide range of spectral coverage in the visible and infrared regions. QDs have good photochemical stability, extreme brightness, broad excitation spectral range, narrow and symmetric emission spectra which are independent of the excitation frequency, and they do not photo-bleach because there is no absorption throughout the specimen due to illumination. All this together make QDs ideal for achieving a considerably improved performance of fluorescence-based optical imaging.

For more information on this research topic please contact Hans Ågren or Ying Fu. You can also search our publications list

Some links to other biophotonics-related pages: