Nano-sized metal particles are attracting much interest in industrial and biomedical applications due to the recent progress and development of nanotechnology, and the surface-modifications by appropriate polymers are key techniques to stably express their characteristics. Herein, we applied cyclic poly(ethylene glycol) (c-PEG), having no chemical inhomogeneity, to provide a polymer topology-dependent stabilization for the surface-modification of gold nanoparticles (AuNPs) through physisorption. By simply mixing c-PEG, but not linear counterparts, enables AuNPs to maintain dispersibility through freezing, lyophilization, or heating. Surprisingly, c-PEG endowed AuNPs with even better dispersion stability than thiolated PEG (HS–PEG–OMe). The stronger affinity of c-PEG was confirmed by DLS, ζ-potential, and FT-IR. Furthermore, the c-PEG system exhibited prolonged blood circulation and enhanced tumor accumulation in mice. Our data suggests that c-PEG induces physisorption on AuNPs, supplying sufficient stability toward bio-medical applications, and would be an alternative approach to the gold–sulfur chemisorption.

由于纳米技术的最新进展和发展，纳米级金属颗粒在工业和生物医学应用中引起了极大的兴趣，并且通过适当的聚合物进行的表面改性是稳定地表达其特性的关键技术。在这里，我们应用了不具有化学不均一性的环状聚乙二醇（c -PEG），以通过物理吸附为金纳米颗粒（AuNPs）的表面改性提供聚合物拓扑结构依赖性的稳定作用。通过简单地混合c -PEG，而不是线性对应物，可使AuNP通过冷冻，冻干或加热保持分散性。令人惊讶的是，c-PEG使AuNPs的分散稳定性比硫醇化PEG（HS-PEG-OMe）更好。通过DLS，ζ电势和FT-IR证实了c -PEG的较强亲和力。此外，c -PEG系统在小鼠中表现出延长的血液循环和增强的肿瘤积累。我们的数据表明，c -PEG诱导AuNPs上的物理吸附，为生物医学应用提供足够的稳定性，并且将是金-硫化学吸附的替代方法。