Kulzer Florian, Laurens Niels, Besser Jaya, Schmidt Thomas, Orrit Michel, Spaink Herman P
Institute of Biology, Leiden University, P.O. Box 9505, 2300 RA Leiden, The Netherlands.
Chemphyschem. 2008 Aug 25;9(12):1761-6. doi: 10.1002/cphc.200800127.
We use photothermal microscopy to detect and image individual gold nanoparticles that are either embedded in a polymer film or immobilized in an aqueous environment. Reducing the numerical aperture of the detection optics allows us to achieve a 200-fold-enlarged detection volume while still retaining sufficient detectivity. We characterize the capabilities of this approach for the detection of gold colloids with a diameter of 20 nm, with emphasis on practical aspects that are important for high-throughput-screening applications. The extended detection volume in combination with the stability of the photothermal signal are major advantages compared to fluorescence-based approaches, which are limited by photoblinking and photobleaching. Careful consideration is given to the trade-off between the maximum increase in local temperature that can be tolerated by a biological specimen and the minimum integration time needed to reliably determine whether a given volume contains a target species. We find that our approach has the potential to increase the detection-limited flow rate (i.e. the limit given by the detection volume divided by the minimum detection time) by two to three orders of magnitude.
我们使用光热显微镜来检测和成像嵌入聚合物薄膜或固定在水性环境中的单个金纳米颗粒。减小检测光学器件的数值孔径使我们能够实现200倍扩大的检测体积，同时仍保持足够的检测能力。我们表征了这种方法检测直径为20 nm的金胶体的能力，重点关注对高通量筛选应用很重要的实际方面。与受光闪烁和光漂白限制的基于荧光的方法相比，扩展的检测体积与光热信号的稳定性相结合是主要优势。我们仔细考虑了生物样本能够耐受的局部温度的最大升高与可靠确定给定体积是否包含目标物种所需的最小积分时间之间的权衡。我们发现我们的方法有可能将检测限制流速（即检测体积除以最小检测时间得出的限制）提高两到三个数量级。
