Optical Sciences

Biomolecules and nanostructures

The Optical Sciences group studies the interaction of light and matter at the nanoscale. We do this by exploring ways to shape light and its environment. It's what we call active and passive control. Our current focus is on the interaction of light with biomolecules and nanostructures. We are part of Twente University's Department of Science and Technology and member of the MESA+ institute.
We participate in the EU-COST actions MP1102: Coherent Raman microscopy (MicroCor) and CM1202: Supramolecular photocatalytic water splitting (PERSPECT-H2O)


Near-field fluorescence imaging of genetic material: Toward the molecular limit

vanHulst NF, GarciaParajo MF, Moers MHP, Veerman JA, Ruiter AGT
vol 119 issue 2: p222-p231 1997

Chromosomes, DNA, and single fluorescent molecules are studied using an aperture-type near-held scanning optical microscope with tuning fork shear force feedback. Fluorescence in situ hybridization labels o­n repetitive and single copy probes o­n human metaphase chromosomes are imaged with a width of 80 nm, allowing their localization with nanometer accuracy, in direct correlation with the simultaneously obtained topography. Single fluorophores, both in polymer and covalently attached to amino- silanized glass, are imaged using two-channel fluorescence polarization detection. The molecules are selectively excited according to their dipole orientation. The orientation of the dipole moment of all molecules in o­ne image could be directly determined. Rotational dynamics o­n a 10-ms to 100-s timescale is observed. Finally, shear force imaging of double-stranded DNA with a vertical sensitivity of 0.2 nm is presented. A DNA height of 1.4 nm is measured, which indicates the nondisturbing character of the shear force mechanism. (C) 1997 Academic Press.
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