Institute of Applied Physics, National Research Council of Italy, Via Madonna del Piano, 10, 50019, Sesto Fiorentino, Italy.
J Nanobiotechnology. 2018 Jan 19;16(1):5. doi: 10.1186/s12951-017-0329-7.
Gold nanorods (GNRs) display unique capacity to absorb and scatter near infrared light, which arises from their peculiar composition of surface plasmon resonances. For this reason, GNRs have become an innovative material of great hope in nanomedicine, in particular for imaging and therapy of cancer, as well as in photonic sensing of biological agents and toxic compounds for e.g. biomedical diagnostics, forensic analysis and environmental monitoring. As the use of GNRs is becoming more and more popular, in all these contexts, there is emerging a latent need for simple and versatile protocols for their modification with targeting units that may convey high specificity for any analyte of interest of an end-user.
We introduce protein G-coated GNRs as a versatile solution for the oriented immobilization of antibodies in a single step of mixing. We assess this strategy against more standard covalent binding of antibodies, in terms of biocompatibility and efficiency of molecular recognition in buffer, serum and plasma, in the context of the development of a direct immunoenzymatic assay. In both cases, we estimate an average of around 30 events of molecular recognition per particle. In addition, we disclose a convenient protocol to store these particles for months in a freezer, without any detrimental effect.
The biocompatibility and efficiency of molecular recognition is similar in either case of GNRs that are modified with antibodies by covalent binding or oriented immobilization through protein G. However, protein G-coated GNRs are most attractive for an end-user, owing to their unique versatility and ease of bioconjugation with antibodies of her/his choice.
金纳米棒（GNRs）具有独特的吸收和散射近红外光的能力，这源于其表面等离子体共振的特殊组成。出于这个原因，GNRs 已经成为纳米医学中极具希望的创新材料，特别是在癌症的成像和治疗，以及生物制剂和有毒化合物的光子传感方面，例如用于生物医学诊断、法医分析和环境监测。随着 GNRs 的应用越来越广泛，在所有这些情况下，都需要一种简单而通用的方法来修饰它们，使其带有靶向单元，从而为最终用户感兴趣的任何分析物提供高度特异性。
我们介绍了蛋白 G 涂层的 GNRs，作为一种在混合的单一步骤中定向固定抗体的通用解决方案。我们在缓冲液、血清和血浆中评估了这种策略在生物相容性和分子识别效率方面与更标准的抗体共价结合的比较，以开发直接免疫酶测定法。在这两种情况下，我们估计每个颗粒平均有大约 30 次分子识别事件。此外，我们还披露了一种方便的方案，可以将这些颗粒储存在冰箱中数月，而不会造成任何不利影响。
通过共价结合或通过蛋白 G 定向固定修饰抗体的 GNRs 的分子识别的生物相容性和效率是相似的。然而，对于最终用户来说，蛋白 G 涂层的 GNRs 更具吸引力，因为它们具有独特的通用性和易于与她/他选择的抗体进行生物偶联。
