title: A minimal optical trapping and imaging microscopy system.
abstract: We report the construction and testing of a simple and versatile optical trapping apparatus, suitable for visualizing individual microtubules (∼25 nm in diameter) and performing single-molecule studies, using a minimal set of components. This design is based on a conventional, inverted microscope, operating under plain bright field illumination. A single laser beam enables standard optical trapping and the measurement of molecular displacements and forces, whereas digital image processing affords real-time sample visualization with reduced noise and enhanced contrast. We have tested our trapping and imaging instrument by measuring the persistence length of individual double-stranded DNA molecules, and by following the stepping of single kinesin motor proteins along clearly imaged microtubules. The approach presented here provides a straightforward alternative for studies of biomaterials and individual biomolecules.
authors: Program in Molecular Biology, Instituto Potosino de Investigación Científica y Tecnológica, San Luis Potosí, Mexico.
authors: Carmen Noemí
authors: CN
authors: Hernández Candia
authors: Sara
authors: S
authors: Tafoya Martínez
authors: Braulio
authors: B
authors: Gutiérrez-Medina
mesh_terms: D002138:Calibration; D004247:DNA / Q000648:ultrastructure; D016547:Kinesins / Q000378:metabolism; D008853:Microscopy / Q000379:methods*
chemical_list: D004247:DNA; D016547:Kinesins