Micromanipulation by Light in Biology and Medicine

2.2.4 Working in the interior of closed objects.- 2.3 Interaction of optical tweezers with biological material.- 2.3.1 The wavelength makes the difference.- 2.3.2 Thermal effects in continuous laser microbeams.- 2.3.3 Interaction of NdYAG optical tweezers (1064nm) with cells.- 2.3.4 The surprise: NdYAG lasers are not the best choice.- 2.3.5 Two-photon excited fluorescence for detecting damage in IR optical traps.- 2.4 Light pressure: Some quantitative relationships.- 2.4.1 Calculating some surprising facts.- 2.4.2 Mie particles: The color of the target affects the light force.- 2.4.3 Light forces on very small (Rayleigh) particles.- 2.5 Gradient forces: Full control in three dimensions.- 2.5.1 Axial and transversal effects.- 2.5.2 Why are particles pushed towards the optical axis?.- 2.5.3 Why are particles pulled against the light pressure force?.- 2.5.4 Quantitative influence of objective illumination and of refractive indices.- 2.6 Unprecedented accuracy and precision: Nanometers and piconewtons.- 2.6.1 The escape force method for calibrating optical tweezers.- 2.6.2 The stiffness method.- 2.6.3 Calibration by thermal motion: The corner frequency method.- 2.6.4 Calibration by thermal motion: The minimal information method.- 2.6.5 Split photodiodes and interferometers for nanometer accuracies.- 3 From the first simple experiments to sophisticated applications of laser microtools.- 3.1 Microbeams in developmental biology.- 3.1.1 Drosophila: From the embryos to the organism.- 3.1.2 Laser microbeams study of the development of the roundworm Caenorhabditis elegans.- 3.1.3 The nervous system of Caenorhabditis elegans.- 3.1.4 Other nervous systems.- 3.1.5 Plant root development: Clonal or positional determination of cell fate?.- 3.2 Intermezzo I: Cells and cellular organelles.- 3.2.1 Prokaryotic cells: Bacteria.- 3.2.2 Cell membranes.- 3.2.3 Eukaryotic cells: Cells with a nucleus.- 3.2.4 The nucleus of eukaryotic cells.- 3.2.5 The cytoskelton and structure-stabilizing intracellular strands.- 3.2.6 Subcellular structures: Mitochondria and chloroplasts.- 3.2.7 Cell types for work with laser microbeams and optical tweezers.- 3.3 Laser microbeam studies on unicellular organisms, cells and subcellular structures.- 3.3.1 Negative and positive chemotaxis induced by laser ablation.- 3.3.2 Laser microbeam treatment of flagella, cilia and pseudopodia in unicellular organisms.- 3.3.3 Ablation of melanophores in fish.- 3.3.4 Ablation of mitochondria to study heart function.- 3.3.5 Nucleoli.- 3.3.6 Actomyosin fibrils and cytoplasmic strands.- 3.3.7 Laser ablation of interphase chromatin in the nucleus.- 3.4 Optical tweezers enter the stage.- 3.4.1 Optical trapping of viruses and bacteria.- 3.4.2 The step toward infrared optical tweezers.- 3.4.3 Single-cell sorters.- 3.4.4 Brakes for biological motors: The compliance of bacterial flagella.- 3.4.5 The slipper animalcule survives moving subcellular organelles and the nucleus.- 3.4.6 Neural growth cone membranes.- 4 Mitosis, molecular motors and muscles: What laser microtools can teach us.- 4.1 Intermezzo II: Reproduction and motion.- 4.1.1 The cell cycle.- 4.1.2 Details of mitosis.- 4.1.3 Details of the interphase.- 4.1.4 Microtubules.- 4.1.5 Intracellular traffic: cytoplasmic streaming.- 4.1.6 Molecular motors.- 4.1.7 Forces generated by single molecules.- 4.2 What drives cell division? Laser microtools help to find the answer.- 4.2.1 From the early days to complete micromanipulation by laser light.- 4.2.2 Kinetochores and centrosomes: The secret of symmetric distribution of chromosomes.- 4.2.3 Microablation studies on intranuclear metaphase chromosomes.- 4.2.4 Micotubule polymerization dynamics and flexibility.- 4.3 Molecular motors: True nanotechnology.- 4.3.1 Optical tweezers and single motor protein mechanics.- 4.3.2 Molecular force measurements in vivo: Mitochondria transport in the amoeba Reticulomyxa.- 4.3.3 Kinesin.- 4.3.4 Dynein - not as exact as kinesin.- 4.3.5 Myosin/actin: Single heads can do the work.- 4.3.6 Differences between skeletal and smooth muscle.- 4.3.7 Molecular bungee: Titin.- 4.3.8 Laser microbeams for preparing the smallest functional unit of a muscle.- 5 DNA as a molecular individuum.- 5.1 The ultimate DNA analytics: Single molecules.- 5.1.1 DNA: Astronomical dimensions and unlimited variability.- 5.1.2 Handling of DNA.- 5.1.3 Laser microdissection of single DNA molecules.- 5.1.4 The elasticity of a single DNA molecule.- 5.1.5 Two types of elasticity in DNA.- 5.2 Single molecule DNA reactions.- 5.2.1 From general properties to single molecule reactions.- 5.2.2 Cutting of an individual DNA molecule by the restricition endonucleases Apa 1.- 5.2.3 Transcription against a force.- 5.3 Intermezzo III: Genes, chromosomes and genetic diseases.- 5.3.1 Packing DNA: Chromatin.- 5.3.2 From chromatin to chromosomes.- 5.3.3 Banded chromosomes and cytogenetic nomenclature.- 5.3.4 Genome sizes of different organisms.- 5.3.5 Genetic diseases.- 5.4 Laser microdissection of chromosomes.- 5.4.1 The motivation for microdissection of chromosomes.- 5.4.2 Microdissection of chromosomes.- 5.4.3 Submicroscopic effects of laser microdissection.- 5.4.4 Combined use of laser microbeam and optical tweezers.- 5.4.5 Microcloning.- 5.4.6 PCR (Polymerase Chain Reaction).- 6 From biology to medicine.- 6.1 Laser microtools in plant cell biology.- 6.1.1 Optical trapping in the interior of plant cells.- 6.1.2 Simulating microgravity in the alga Chara.- 6.1.3 Preparing free plant membranes for patch clamp studies.- 6.2 Microperforation of cell walls and cell membranes.- 6.2.1 Laser microinjection: What do biologists want to know.- 6.2.2 Laser-assisted gene transfer into animal cells.- 6.2.3 Direct microinjection of genes into plant cells: The laser is often without alternative.- 6.2.4 Injection of DNA into isolated chloroplasts and into chloroplasts within a plant cell.- 6.3 From laser-induced cell fusion to antibodies and immunology.- 6.3.1 How to avoid sex: Cell fusion in suspension.- 6.3.2 Fusion of plant protoplasts.- 6.3.3 Why single-cell fusion? Some speculation.- 6.3.4 Laser-induced fusion of B cells with myeloma cells.- 6.3.5 Increasing the laser fusion yield by chemicals.- 6.3.6 Increasing the yield by combining laser microbeam and optical tweezers.- 6.3.7 Optical tweezers-based immunosensors and detectors of virus-cell adhesion.- 6.3.8 Optical tweezers reveal details of the attack on the immune system on cancer.- 6.4 Towards medical diagnostics: From blood to cancer.- 6.4.1 Optical tweezers as wall-free microvessels to study red blood cell elasticity.- 6.4.2 Measuring the elasticity of red blood cells.- 6.4.3 Red cell adhesion: Laser tweezers test two models.- 6.4.4 Studies on the isolated membrane skeleton.- 6.4.5 Tissue microdissection in cancer research: Background.- 6.4.6 Laser capture microdissection and laser pressure catapulting.- 6.5 Laser microbeam and optical tweezers in reproduction medicine.- 6.5.1 Laser zona drilling (LZD) and handling of sperm cells by optical tweezers.- 6.5.2 Measuring effects of optical tweezers on sperm motility.- 6.5.3 Laser inactivation of extra pronuclei.- 6.5.4 Helping childless couples: Do laser microtools improve human IVF?.- 6.5.5 A word of caution.- A1 Geometrical optics.- A1.1 From waves to rays.- A1.2 Refraction and reflection.- A1.3 Refraction by a spherical surface.- A1.4 The index of refraction for selected materials.- A1.5 Wavelength dependence on the index of refraction.- A1.6 Reflection below the glancing angle.- A1.7 Coating of optical elements.- A1.8 Light guides: Simple optical instruments.- A1.9 Prisms.- A2 Ray optics: Lenses and image formation.- A2.1 Lenses.- A2.2 Different types of lenses.- A2.3 Imaging by a simple lens.- A2.4 Magnification and the thin lens equation.- A2.5 The magnifying glass.- A2.6 Aberrations, lens errors.- A2.7 The numerical aperture of a lens.- A3 Resolution of a microscope and focusing a laser.- A3.1 The Bessel function and maximal focusing of a laser.- A3.2 The resolution of a microscope.- A3.3 Experimental determination of focal radii.- A3.4 Visibility of objects.- A3.5 Why lasers can be focused better than thermal light.- A4 Light as a wave: Mathematical representation.- A4.1 The wave equations.- A4.2 Polarized light.- A4.3 Interference.- A4.4 Standing waves and modes.- A5 Absorption, scattering and fluorescence.- A5.1 Absorption and scattering make objects visible and allow work to be done on them.- A5.2 Absorption and emission in a two-state atom.- A5.3 The Lambert Beer law.- A5.4 Two- and three-photon absorption.- A5.5 Rayleigh scattering.- A5.6 The detailed two energy state diagram of fluorescence.- A5.7 Fluorescence and phosphorescence lifetimes as a basis for explaining laser action.