Photonics probing of DNA mass density spatial structure for cancer diagnostics

摘要 众所周知，癌症与基因突变有关。有证据表明，这些基因变化导致 导致生物细胞核的结构无序增加。这种疾病被认为是由于改变和 开始时DNA分子质量密度重排。在进行性致癌的情况下， 变化发生在从纳米(&lt；100 nm)到亚微米(&gt；100 nm)的长度尺度上。因此，它 已经认识到，对这些结构变化的衡量和量化可能是一种 潜在的癌症生物标志物。因此，最近的一些研究基于部分波谱和其他 纳米光学技术已经量化了细胞中的纳米级结构特性。然而，这些技术 仍处于早期阶段，需要复杂的新实验设置，因此限制了对这些研究的访问 仅提供给生物医学和生物科学领域的少数研究小组。同时，利用现有的 进行这类研究的光学技术，例如共聚焦显微镜，仍未被探索。有鉴于此，我们已经 开发了一种新的方法，通过结合共聚焦显微镜成像和借鉴自 介观物理，称为逆参与率(IPR)技术，或简称为“IPR技术”，以 测量和量化细胞核结构紊乱的程度。细胞基质的成分高度 异质性，包括维度的多重分形性，例如，在不同尺度上形成的细胞结构。因此， 询问细胞异质性并获得有关结构或DNA分子的定量数据 形态障碍(从常模来看)，一般需要建立一些参数。然而， 利用目前的IPR方法，可以通过以下方式选择性地量化核DNA的结构变化 使用DAPI染色的共焦显微镜照片，并仅用一个参数表示，即&lt；ipr&gt；值。 &lt；ipr&gt；值提供了样本结构无序程度的度量，即“无序强度”。 我们的初步结果表明，核DNA的结构无序和 致癌。因此，在这个方案中，我们将对亚微米尺度的结构无序进行测量和量化 通过IPR从细胞培养和组织中获得的不同正常和癌细胞的核DNA中 共焦显微照片的分析。通过将IPR技术与广泛使用的共焦显微镜相结合，我们 目的：(I)开发一种自动量化技术来测量选择性的结构无序程度 从DAPI染色的共聚焦显微照片中观察细胞器中的分子密度，特别是核DNA 细胞，以及(Ii)校准肝脏、皮肤和骨骼细胞中正常细胞和癌细胞的结构紊乱程度 培养物和组织的核结构。该项目的成功将为癌症检测带来新的方向， 以及基于核DNA的量化结构变化的细胞特征。

Abstract Cancer is known to be associated with genetic mutations. Evidences suggest that these genetic changes lead to increased structural disorder in biological cell nuclei. This disorder is believed to result from alteration and rearrangement of DNA molecular mass density at the beginning. In the case of progressive carcinogenesis, such changes occur at length scales ranging from nano- (<100nm) to submicron (>100nm) scales. Consequently, it has been recognized that measurement and quantification of these structural changes could, therefore, be a potential cancer biomarker. Accordingly, some recent studies based on partial wave spectroscopy and other nano-optical techniques have quantified the nanoscale structural properties in cells. However, these techniques are still in the early stages and require complicated new experimental setup, thus limiting access to these studies to only a handful of research groups in the biomedical and biological sciences. Meanwhile, the use of existing optical techniques, e.g., confocal microscopy, to conduct such studies is still unexplored. In view of that, we have developed a novel method, by combining confocal microscopy imaging and a technique borrowed from mesoscopic physics, termed as inverse participation ratio (IPR) technique, or simply the “IPR technique”, to measure and quantify the degree of structural disorder in cell nuclei. Components of the cellular matrix are highly heterogeneous, including multifractality of dimensions, e.g., cellular structures formed at different scales. Thus, to interrogate cellular heterogeneity and to obtain quantitative data about structural or DNA molecular morphological disorder (from the norm), it is generally necessary to establish a number of parameters. However, with the present IPR approach it is possible to selectively quantify structural changes in the nuclear DNA, by using DAPI stained confocal micrographs, and represent it in just one single parameter, namely the <IPR> value. The <IPR> value provides a measure of the degree of structural disorder, i.e., “disorder strength”, of the sample. Our preliminary results show an underlying relationship between structural disorder in nuclear DNA and carcinogenesis. Therefore, in this proposal, we will measure and quantify the submicron-scale structural disorder in the nuclear DNA of different normal and cancerous cells, obtained from cell cultures and tissues, via IPR analysis of the confocal micrographs. By coupling the IPR technique to the widely used confocal microscopy, we aim to (i) develop an automated quantification technique to measure the degree of structural disorder of selective molecular density in an organelle, in particular nuclear DNA, from DAPI stained confocal micrographs of the cells, and (ii) calibrate the degree of structural disorder in normal and cancer cells in liver, skin, and skeletal cell cultures and tissues nuclear structure. The success of this project will lead to a new direction in cancer detection, as well as cell characterization based on quantified structural changes in nuclear DNA.