创新背景

基于纸张的横向流动检测与妊娠检测的工作原理相同，即将一张纸浸泡在液体样品中，颜色(或荧光信号)的变化表示阳性结果和检测到病毒蛋白质或DNA。它们被广泛用于检测从艾滋病毒到SARS-CoV-2等病毒(Covid-19的横向流动检测目前正在英国试点)，并可以提供快速诊断，因为检测结果不需要在实验室中处理。

创新过程

这项发表在《自然》杂志上的新研究发现，低成本的纳米钻石可以用来检测HIV疾病标记物的存在，其灵敏度是这些测试中广泛使用的金纳米颗粒的数千倍。
该研究团队正在努力调整新技术，以便在未来几个月检测COVID-19和其他疾病。关键的下一步是开发一种可以“读取”结果的手持设备，因为该技术是在实验室的显微镜下演示的。还计划进行进一步的临床评价研究。
首席作者、伦敦大学学院生物医学纳米技术教授、i-sense EPSRC IRC主任Rachel McKendry教授说:“我们的概念验证研究表明，量子技术可以用于检测患者样本中极低水平的病毒，从而实现更早的诊断。”

NV中心可以通过发射明亮的荧光灯发出抗原或其他目标分子存在的信号。在过去，荧光标记受到来自样品或试纸的背景荧光的限制，使得很难检测到低浓度的病毒蛋白质或DNA，而这将表明检测结果为阳性。然而，荧光纳米金刚石的量子特性允许选择性地调制其发射，这意味着可以使用微波场将信号固定在一个设定的频率上，并可以有效地从背景荧光中分离出来，解决了这一限制。
光学结果显示，与金纳米颗粒相比，灵敏度提高了5个数量级(10万倍)(也就是说，产生可检测信号所需的纳米颗粒数量要少得多)。在短短的10分钟恒温扩增步骤中，RNA的拷贝被复制，研究人员能够在一个模型样本的单分子水平上检测到HIV RNA。

这项工作是在实验室环境下进行的，但该团队希望开发测试，以便用智能手机或便携式荧光阅读器读取结果。这意味着，在未来，该测试可以在低资源设置下执行，使用户更容易访问它。
第一作者Ben Miller博士(伦敦大学学院伦敦纳米技术中心i-sense博士后助理研究员)说:“使用金纳米颗粒的纸质横向流动测试不需要实验室分析，这使得它们在资源匮乏和医疗保健有限的地方特别有用。它们成本低，携带方便，使用方便。
“然而，这些检测目前缺乏检测极低水平生物标志物的敏感性。通过在这种新设计中用荧光纳米钻石取代常用的金纳米颗粒，并选择性地调制它们(已经很亮)的光发射，我们已经能够将它们的信号从测试条的不需要的背景荧光中分离出来，显著提高了灵敏度。”
伦敦大学学院量子科学与技术研究所(UCLQ)主任、该论文的合著者约翰·莫顿教授说:“伦敦大学学院和LCN的i-sense团队之间的跨学科合作是一个奇妙的例子，说明了量子系统的基础工作，如钻石中的NV中心，如何从实验室发展起来，并在传感和诊断的现实应用中发挥关键作用。UCLQ的研究人员正在通过与工业界和其他学术研究团体合作，探索并实现这些和其他量子技术的影响。”

创新价值

这种更高的灵敏度使检测到的病毒载量更低，这意味着该检测可以检测到较低水平的疾病，或在更早的阶段检测到疾病，这对于降低受感染者的传播风险和有效治疗艾滋病毒等疾病至关重要。

创新关键点

研究人员利用纳米钻石的量子特性制造出精确的不完美。钻石高度规则结构中的这种缺陷产生了所谓的氮空位(NV)中心。NV中心有许多潜在的应用，从用于超灵敏成像的荧光生物标记到量子计算中的信息处理量子位。

创新主体

伦敦大学学院（University College London，简称：UCL ），1826年创立于英国伦敦，是一所公立研究型大学，为伦敦大学联盟的创校学院、罗素大学集团和欧洲研究型大学联盟创始成员，被誉为金三角名校和“G5超级精英大学”之一。
UCL是伦敦的第一所大学，以其多元的学科设置著称，于REF 2014 英国大学官方排名中，位列全英之冠，享有最多的科研经费。UCL的医学、解剖学和生理学、建筑学、教育学、考古学、计算机科学、计算金融学等学科排名均位居世界前列，与LSE并称为“英国现代经济学研究的双子星”；其人文学院颁发的奥威尔奖则是政治写作界的最高荣誉。

The use of quantum nanodiamonds can help detect diseases earlier

The new study, published in the journal Nature, found that low-cost nanodiamonds could be used to detect the presence of HIV disease markers with thousands of times more sensitivity than the gold nanoparticles widely used in these tests.
The research team is working to adapt the new technology to detect COVID-19 and other diseases in the coming months. A key next step is to develop a handheld device that can "read" the results, as the technology is demonstrated under a microscope in a laboratory. Further clinical evaluation studies are planned.
Lead author Professor Rachel McKendry, Professor of Biomedical Nanotechnology at UCL and director of I-Sense EPSRC IRC, said: "Our proof-of-concept study shows that quantum technology can be used to detect very low levels of virus in patient samples, enabling earlier diagnosis.
NV centers can signal the presence of antigens or other target molecules by emitting bright fluorescent lights. In the past, fluorescent labeling was limited by background fluorescence from the sample or strip, making it difficult to detect low concentrations of viral proteins or DNA that would indicate a positive test result. However, the quantum properties of fluorescent nanodiamonds allow selective modulation of their emission, which means that the signal can be fixed to a set frequency using a microwave field and can be effectively separated from background fluorescence, addressing this limitation.
The optical results show a sensitivity increase of five orders of magnitude (100,000 times) compared to gold nanoparticles (that is, a much smaller number of nanoparticles are required to produce a detectable signal). In a short 10-minute thermostatic amplification step, copies of the RNA were replicated, and the researchers were able to detect HIV RNA at the single-molecule level in a model sample.
The work was carried out in a laboratory setting, but the team hopes to develop tests so that the results can be read with a smartphone or portable fluorescent reader. This means that, in the future, the test could be performed at a low resource setting, making it easier for users to access.
First author Dr Ben Miller (I-Sense Postdoctoral Research Associate, UCL London Centre for Nanotechnology) said: "Paper lateral flow tests using gold nanoparticles do not require laboratory analysis, making them particularly useful in places with low resources and limited healthcare. They are low cost, easy to carry and easy to use.
"However, these tests currently lack the sensitivity to detect very low levels of biomarkers. By replacing commonly used gold nanoparticles with fluorescent nanodiamonds in this new design and selectively modulating their (already bright) light emission, we have been able to separate their signal from the unwanted background fluorescence of the test strip, significantly increasing the sensitivity."
Professor John Morton, director of UCL's Institute of Quantum Science and Technology (UCLQ) and co-author of the paper, said: "The interdisciplinary collaboration between UCL and LCN's I-Sense team is a fantastic example of how fundamental work on quantum systems, such as the NV centre in diamonds, can grow from the laboratory, And play a key role in real-world applications of sensing and diagnostics. UCLQ researchers are exploring and realizing the impact of these and other quantum technologies by collaborating with industry and other academic research communities."