Light It Up: A Nanotechnology Approach for the Acquisition of Forensic Evidence

想象你正在看一个破案的电视节目。法医在犯罪现场发现了一条牛仔裤。他们给它们喷上一种溶液，点燃他们的“火炬”，很快，血液、精液和唾液就会呈现出不同颜色的明亮光点。科学家们能够识别出存在的物质，然后分别提取每种体液的样本，以获得存放每种体液的人的DNA图谱。这是现实吗？否。远非如此。目前，进行不同的分析（每种分析需要不同的化学品和设备）来检测和识别每种体液。这是非常耗时的——当警察等待可能帮助他们破案的结果时，这是一个重要因素。目前的方法也很难检测到体液的微小痕迹。鉴于现在有可能从单个细胞中获得DNA档案，在犯罪现场收集DNA痕迹至关重要。我们提出的研究目标是通过制造一种溶液，将电视小说变成现实，当喷洒在法医证据上时，它会使任何血液、精液或唾液的痕迹发出荧光，这样法医科学家就能很容易地识别出体液的位置（更重要的是，哪些体液存在），这样他们就可以把它们取出来进行DNA分析。我们的解决方案被称为“点亮它”，它是基于一种叫做纳米粒子的微小粒子。每个纳米粒子将被抗体（识别并结合另一个伙伴分子的生物分子）包裹，这种抗体只会特异性地结合一种体液。抗体上有荧光标签，这样当专业的法医光源照射到物品上时，体液所在的区域就会发出不同颜色的荧光，每种颜色代表一种特定的目标液体。例如，精液呈蓝色，唾液呈绿色，血液呈红色。了解存在哪些体液可以为警方调查提供至关重要的确凿证据，有助于支持或反驳嫌疑人、受害者或证人的陈述。“点亮它”会很容易地提供这些信息。由于我们的技术使用纳米颗粒，我们可以利用一定的尺寸尺度特性来提高“Light It Up”的检测灵敏度。在磁铁的存在下，铁纳米颗粒具有磁性。因此，如果纳米颗粒没有与生物流体结合，它们可以简单地用磁铁去除。随着“点亮它”的非束缚粒子被移除，束缚粒子将更容易出现。我们还致力于开发一种“点亮它”的解决方案，它将直接在原位检测DNA。当法医科学家寻找生物体液时，他们真正寻找的是DNA（尽管他们也想要关于体液类型的信息来帮助警方进行调查）。最后，我们希望确定我们是否可以使用“Light It Up”为警方提供可以指导他们调查的信息。例如，我们想确定我们是否可以在犯罪现场留下的指纹中检测到爆炸物残留物，以及在指纹和体液中检测到毒品和药物代谢物。我们的抗体纳米粒子技术会特别结合这些目标，发出荧光信号，使警方能够集中搜寻处理爆炸性物料的人，或交易及/或使用毒品的人。这些信息无疑会帮助警方找到正确的调查方向。

Imagine you are watching a crime-solving TV programme. The forensic scientists have found a pair of jeans at a crime scene. They spray them with a solution, shine their 'torches' and, hey presto, blood, semen and saliva show up as brightly glowing spots each of a different colour. The scientists are able to identify what is present and then take a sample of each body fluid separately to obtain the DNA profile of the person who deposited each fluid. Is this reality? No. Far from it. Currently, a different analysis (each requiring different chemicals and equipment) is carried out to detect and identify each of these body fluids. This is very time consuming - an important factor when police are waiting for results which may help them solve a crime. The current methods also struggle to detect small traces of body fluids. Given that it is now possible to obtain a DNA profile from a single cell, collecting traces of DNA at crime scenes is vital.Our proposed research aims to make TV fiction a reality by producing a solution which, when sprayed on items of forensic evidence, will cause any traces of blood, semen or saliva to fluoresce, so that forensic scientists are readily able to identify where the body fluids are located (and, importantly, which ones are present) so that they can remove them for DNA profiling. 'Light It Up', as our solution is called, is based on minute particles called nanoparticles. Each nanoparticle will be coated with antibodies (biological molecules which recognise and bind to another partner molecule) which will specifically bind to only one body fluid. The antibodies will have fluorescent tags on them so that when specialist forensic light sources are shone on the item, the area where the body fluids are located will fluoresce with different colours, each colour representing a particular target fluid. For example, semen will show up as blue, saliva as green and blood as red. Knowing which body fluid is present can provide vital corroborative evidence for police investigations helping to support or refute suspect, victim or witness statements. 'Light It Up' will readily provide this information. As our technology uses nanoparticles, we can exploit certain size scale properties to improve the detection sensitivity of 'Light It Up'. In the presence of a magnet, iron nanoparticles are magnetic. Hence, if the nanoparticles are not bound to a biological fluid they can be simply removed using a magnet. With non-bound particles of 'Light It Up' removed, the bound particles will show up much more readily. We also aim to develop a solution of 'Light It Up' which will detect DNA directly in situ. It's the DNA that forensic scientists are really looking for when they search for biological fluids (although they also want information on the type of body fluid to help the police in their investigations). Finally, we wish to determine whether we can use 'Light It Up' to provide the police with information which can guide them in their investigations. For example, we want to establish whether we can detect explosive residues in fingerprints left at a crime scene and, for drugs and drug metabolites, in both fingerprints and body fluids. Our antibody-nanoparticle technology will specifically bind to such targets giving a fluorescent signal enabling the Police to focus their search for people handling explosive materials or dealing and/or using drugs respectively. Such information would undoubtedly help point the police in the right direction for their investigations.