System for Laser/Mechanical Dissection of Chromosomes

越来越多的疾病与特定的染色体异常有关，如易位、倒位和缺失。 单个染色体G带的选择允许制备用于染色体分析和鉴定这些异常的临床诊断探针。目前，通过用连接到液压操纵器的微量移液管将其从载玻片上刮下，同时使用配备有100 X物镜透镜的倒置显微镜监测该过程，来去除所需的染色体带。 大致垂直于感兴趣的染色体定向的针既将期望的材料与染色体的其余部分区分开，又将材料移除用于后续处理。 在我们开发的一个新系统中，使用UV（390 nm）激光器来非常清晰地标定待采集的材料，并烧蚀紧邻的周围材料。 然后，在计算机控制下，用一种专门开发的机构移动微量移液管来移走所需的材料。 希望通过依靠激光来修剪掉不需要的材料，与使用微量移液管的剪切作用将样品从剩余材料中分离出来时相比，将存在更少的外来材料。 此外，通过用物镜透镜焦点位置和视频图像感测针尖位置，以及采用计算机来确定机构的运动，将大大降低对操作者的手动灵活性要求，从而允许该技术更广泛地使用。 目前正在对新系统进行评估。

An increasing number of diseases are being associated with specific chromosomal abnormalities, such as translocations, inversions, and deletions. Selection of individual chromosome G-bands allows preparation of clinical diagnostic probes for chromosomal analysis and identification of these abnormalities. Presently, the desired chromosome band is removed by scraping it off a slide with a micropipette attached to a hydraulic manipulator while monitoring the process using an inverted microscope equipped with a 100X objective lens. The needle, oriented approximately perpendicularly to the chromosome of interest both demarcates the desired material from the rest of the chromosome, and removes the material for subsequent processing. In a new system we have developed, a UV (390nm) laser is used to very sharply demarcate the material to be acquired and ablate the immediate surrounding material. The desired material is then removed by a micropipette moved by a specially developed mechanism under computer control. It is hoped that by relying on the laser to trim away the undesired material, there will be less extraneous material than when the shearing action of the micropipette is used to separate out the sample from the remaining material. In addition, by sensing the needle tip position with the objective lens focus position and a video image, as well as employing a computer to determine the motions of a mechanism, the manual dexterity requirements on the operator will be greatly reduced, thus allowing the technique to be more widely used. The new system is currently being evaluated.