粒子粒子相互作用采用胶体探针纳米显微定量和定性检查
Summary
Colloidal probe nanoscopy can be used within a variety of fields to gain insight into the physical stability and coagulation kinetics of colloidal systems and aid in drug discovery and formulation sciences using biological systems. The method described within provides a quantitative and qualitative means to study such systems.
Abstract
Colloidal Probe Nanoscopy (CPN), the study of the nano-scale interactive forces between a specifically prepared colloidal probe and any chosen substrate using the Atomic Force Microscope (AFM), can provide key insights into physical interactions present within colloidal systems. Colloidal systems are widely existent in several applications including, pharmaceuticals, foods, paints, paper, soil and minerals, detergents, printing and much more.1-3 Furthermore, colloids can exist in many states such as emulsions, foams and suspensions. Using colloidal probe nanoscopy one can obtain key information on the adhesive properties, binding energies and even gain insight into the physical stability and coagulation kinetics of the colloids present within. Additionally, colloidal probe nanoscopy can be used with biological cells to aid in drug discovery and formulation development. In this paper we describe a method for conducting colloidal probe nanoscopy, discuss key factors that are important to consider during the measurement, and show that both quantitative and qualitative data that can be obtained from such measurements.
Introduction
原子力显微镜（AFM）是一种技术，它使定性和定量成像和探测的材料的表面。4-6传统AFM用于表面形貌，形貌和多相位材料的结构的评估。 AFM具有定量评价纳米尺度相互作用，如在空气和液体介质的特定探针和基板之间的电荷，吸引，排斥和粘附力的能力。7,8最初由分级，第四纪和Gerber 9的用途开发的原子力显微镜探测已知的/确定的灵敏度和弹性系数接近和/或扫描样本。由于探针与样品之间的物理相互作用，悬臂接触或接近时偏转，这取决于操作的模式下，该偏转可以被转换为获得本探针和样品之间的样品或测量力的地形。修改的原子力显微镜TECHNI阙，如胶体探针纳米显微，10已允许科学家直接评价存在于感兴趣的胶体系统，两种材料间的纳米相互作用力。
在胶体探针纳米显微，选择的球形颗粒附着到悬臂的先端，取代了传统的圆锥形和棱锥形的提示。球形粒子是理想的，允许与理论模型，如强生，肯德尔，罗伯茨（JKR）11和Derjaguin，朗多，Vervwey，Overbeek（DLVO）12-14理论，并尽量减少表面粗糙度对测量的影响比较。 15这些理论用于定义接触力学和颗粒间力预期的胶体系统中。 DLVO理论结合了有吸引力的范德华力和静电排斥力（由于双电层）来定量解释含水的胶体体系的聚集行为，而歼KR理论结合的接触压力和粘附到模型两个组件之间的弹性接触的效果。一旦适当的探针产生的，它被用来逼近的任何其它材料/颗粒，以评估在两个部件之间的力。使用制造的小费标准之一将是能够测量的尖端和选择的材料之间的相互作用力，但使用一个定制的胶体探针的利益使得目前所研究的系统中存在材料之间的力的测量。可测量相互作用包括：粘合剂，有吸引力，排斥力，电荷和存在于粒子之间甚至静电力16此外，胶体探针技术可以用来探索本颗粒和弹性材料之间的切向力17,18
进行测量，在各种媒体的能力是胶体探针纳米显微的主要优点之一。环境条件，液态间EDIA，或湿度可控的条件下都可以被用来模仿所研究的系统的环境条件。进行测量，在液体环境中的能力，使胶体系统中，它天然存在的环境中的研究;因此，能够定量地采集数据是直接翻译的系统在其自然状态。例如，定量吸入器（MDI）中存在粒子的相互作用可以用一个模型液体推进剂具有类似属性的计量吸入器所用的推进剂进行研究。在空气中测得相同的相互作用并不能代表在吸入器系统存在的。此外，液体介质可以被修改来评价水分侵入，二次表面活性剂，或温度上在MDI粒子相互作用的影响。以控制温度的能力，可用于模拟在胶体系统的制造某些步骤以评估温度无论是在制造或存储胶体系统可能对粒子的相互作用产生影响。
可以使用胶体探针来获得测量包括;地形扫描，个人的力量 – 距离曲线，力 – 距离粘连的地图里，住力距离测量。正在使用本文介绍的胶体探针纳米显微方法测量关键参数包括管理单元，最大负荷和分离能量值。管理单元是引力的测量，最大负载的最大附着力的价值，以及分离能传达到从接触撤回粒子所需的能量。这些值可以通过瞬时或停留力的测量来测量。两种不同类型的停留测量包括变形和压痕。驻留测量的长度和类型可以专门选择模仿所关心的系统中存在特异性相互作用。一个例子是使用偏转停留 – 持有来评估发展中形成的聚集体分散体胶粘剂债券 – 在希望的弯沉值在接触样品。所形成的粘合剂粘结可以测量作为时间的函数，并且可以提供深入了解再分散后的长期储存的聚集体所需的力。数据可以使用这种方法获得的大量证明了该方法的通用性。
Protocol
Representative Results
Discussion
系统不稳定时液体胶体探针纳米显微目前的几个来源可以很容易地通过适当的平衡过程来缓解。所讨论的不稳定性先前导致错误的结果和力曲线更难以客观分析。如果不稳定的所有来源已趋向和图形相似，在图4所示的仍然存在，另一次测量的参数可以是原因。这是要考虑的重要过程中的胶体探针纳米显微其他测量参数包括在该悬臂啮合并从样品回缩的速度和力测量的触发点。另外，?…
Divulgations
The authors have nothing to disclose.
Acknowledgements
作者承认（1）从纳米生物医学科学与BK21 PLUS NBM全球研究再生医学中心的檀国大学，并系资金支持的重点由NRF，大韩民国，（资助研究中心计划（编号2009-0093829） 2）设施，科学和技术援助的澳大利亚中心显微镜和微量分析在悉尼大学。 HKC感谢澳大利亚研究理事会通过发现项目补助（DP0985367＆DP120102778）的财务支持。世界锦标赛是感谢澳大利亚研究理事会通过联动项目补助（LP120200489，LP110200316）的财务支持。
Materials
| Name of Material/ Equipment | Company | Catalog Number | Comments/Description |
| Double-Bubble Epoxy | Hardman | 4004 | |
| Veeco Tipless Probes | Veeco | NP-O10 | |
| Porous Particles | Pearl Therapeutics | N/A | |
| Atomic Force Microscope (MFP) | Asylum | MFP-3D | |
| SPIP Scanning Probe Image Processor Software | NanoScience Instruments | N/A | |
| 35 mm Coverslips | Asylum | 504.003 | |
| Tempfix | Ted Pella. Inc. | 16030 |
References
- Sindel, U., Zimmermann, I. Measurement of interaction forces between individual powder particles using an atomic force microscope. Powder Technology. 117, 247-254 (2001).
- Ducker, W. A., Senden, T. J., Pashley, R. M. Direct measurement of colloidal forces using an atomic force microscope. Nature. 353, 239-241 (1991).
- Israelachvili, J. N., Adams, G. E. Measurement of forces between two mica surfaces in aqueous electrolyte solutions in the range 0–100 nm. Journal of the Chemical Society, Faraday Transactions. 1, 975-1001 (1978).
- Upadhyay, D., et al. Magnetised thermo responsive lipid vehicles for targeted and controlled lung drug delivery. Pharmaceutical Research. 29, 2456-2467 (2012).
- Chrzanowski, W., et al. Biointerface: protein enhanced stem cells binding to implant surface. Journal of Materials Science: Materials in Medicine. 23, 2203-2215 (2012).
- Chrzanowski, W., et al. Nanomechanical evaluation of nickel–titanium surface properties after alkali and electrochemical treatments. Journal of The Royal Society Interface. 5, 1009-1022 (2008).
- Tran, C. T., Kondyurin, A., Chrzanowski, W., Bilek, M. M., McKenzie, D. R. Influence of pH on yeast immobilization on polystyrene surfaces modified by energetic ion bombardment. Colloids and Surfaces B: Biointerfaces. 104, 145-152 (2013).
- Page, K., et al. Study of the adhesion of Staphylococcus aureus to coated glass substrates. Journal of materials science. 46, 6355-6363 (2011).
- Binnig, G., Quate, C. F., Gerber, C. Atomic force microscope. Physical Review Letters. 56, 930-933 (1103).
- Butt, H. -. J. Measuring electrostatic, van der Waals, and hydration forces in electrolyte solutions with an atomic force microscope. Biophysical Journal. 60, 1438-1444 (1991).
- Johnson, K., Kendall, K., Roberts, A. Surface energy and the contact of elastic solids. Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences. 324, 301-313 (1971).
- Deraguin, B., Landau, L. Theory of the stability of strongly charged lyophobic sols and of the adhesion of strongly charged particles in solution of electrolytes. Acta Physicochim: USSR. 14, 633-662 (1941).
- Derjaguin, B., Muller, V., Toporov, Y. P. Effect of contact deformations on the adhesion of particles. Journal of Colloid and Interface Science. 53, 314-326 (1975).
- Verwey, E. J. W., Overbeek, J. T. G. Theory of the stability of lyophobic colloids. DoverPublications.com, doi:10.1021/j150453a001. , (1999).
- Kappl, M., Butt, H. J. The colloidal probe technique and its application to adhesion force measurements. Particle & Particle Systems Characterization. 19, 129-143 (2002).
- Tran, C. T., Kondyurin, A., Chrzanowski, W., Bilek, M. M., McKenzie, D. R. Influence of pH on yeast immobilization on polystyrene surfaces modified by energetic ion bombardment. Colloids and Surfaces B: Biointerfaces. , (2012).
- Sa, D. J., de Juan Pardo, E. M., de Las Rivas Astiz, R., Sen, S., Kumar, S. High-throughput indentational elasticity measurements of hydrogel extracellular matrix substrates. Applied Physics Letters. 95, 063701-063701 (2009).
- Zauscher, S., Klingenberg, D. J. Friction between cellulose surfaces measured with colloidal probe microscopy. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 178, 213-229 (2001).
- Sa, D., Chan, H. -. K., Chrzanowski, W. Attachment of Micro- and Nano-particles on Tipless Cantilevers for Colloidal Probe Microscopy. International Journal of Colloid and Interface. , (2014).
