ABSTRACT
Developments in ART (assisted reproductive technologies) are based on scientific data and require artistic skills. Once a new development is well established, and accepted by the scientific and the clinical communities as a proven modality, it usually becomes a simple procedure that has very little to do with the magic of creation in which nature is still The Major Player. However, the more options we have in the AKTbasket, the more artistic skills are needed in order to select the optimal path along the complicated road of procreation. During the summer of 1988 a team of scientists from various continents have gathered at the Laser Medical Microbream Program (LAMMP)/Beckman Laser Institute and Medical Clinic, in the University of California, in order to evaluate the potential use of laser microbeams in the fast moving area of ART. Prior to this time, the only clinical experience with lasers in reproduction was iri tubal reconstructive surgery, where laser beams were delivered through operative microscopes and laparoscopes in order to improve fertility potential, and the effective beam spot size was 300-800 µm.1 At this time, conventional gamete micromanipulation using glass pipettes was also at its very early stage of development, and clinical applications were not defined. The availability of a large variety of laser tools at the LAMMP, with an optional delivery through inverted microscopes to sub-micron spot sizes (Fig 27.1) enabled testing its potential on various cell types, including gametes and embryos.2,3 The main applications of laser beams tested in ART during the past fourteen years were:
a. Sperm manipulations with optical tweezers to improve fertilization in vitro and to study basic sperm physiology of motility force
b. Drilling of oocytes and embryos to improve fertilization potential, assist hatching, remove blastomeres for pre-embryo genetic diagnosis (PGD), and assess zona pellucida (ZP) properties. The purpose of this article is to review the progress and evaluate the current status and potential use of laser microbeams, vis-a-vis other technologies available for gamete micromanipulations, in the ART labo ratory
LASERS AND DELIVERY SYSTEMS AVAILABLE FOR MICROMANIPULATIONS
Lasers, (Light Amplification by Stimulated Emission of Radiation) are electromagnetic waves with unique properties. The beam is collimated, monochromatic and coherent. Lasers differ from each other by the wavelengths (WL), and they are usually in the visible range (red, green or blue), or invisible in the ultra-violet (UV) or infrared (IR)
range. Effects on gametes may also vary as a result of the different parameters used. Some heat may be generated in the micromanipulated object if exposure time is long enough. Conversely, heat formation may be minimized if short exposure time is used in the order of micro (10−6), nano (10−9), or pico-seconds (10−12).
