Supplementary files for "Continuous synthesis of PVP stabilized biocompatible gold nanoparticles with a controlled size using a 3D glass capillary microfluidic device"

Supplementary files for Continuous synthesis of PVP stabilized biocompatible gold nanoparticles with a controlled size using a 3D glass capillary microfluidic device.Abstract:A reliable glass capillary microfluidic method was developed for a continuous production of well-controlled gold nanoparticles (AuNPs) capped with polyvinylpyrrolidone (PVP) of different molecular weights (PVP K15, PVP K30 and PVP K90). A two-phase co-flow glass capillary microfluidic device with an injection orifice diameter ranging between 100 and 240 µm was used to synthesise 100–240 µm was used to synthesise AuNPs via the chemical reduction between tetrachloroaurate trihydrate (HAuCl4·3H2O) and ascorbic acid. AuNPs with an average diameter between 48 and 135 nm were synthesised, as determined by DLS measurements. Decreasing the injection orifice diameter, increasing the flow rate of ascorbic acid stream and its pH resulted in smaller AuNPs. The polydispersity index (PDI) was found to be independent on the injection orifice diameter or the molecular weight of PVP, but increased with the increase of flow rate and the pH of ascorbic acid stream. The stability study over 6-week period confirmed that PVP K30 with an average Mw of 40000 g/mol was the best capping agent to synthesize and stabilise smaller AuNPs. The reactor fouling due to deposition of AuNPs on reactor walls and orifices was mitigated by hydrophobization of reactor/capillary walls with octadecyltrimethoxisilane and the use of ascorbic acid solution of higher pH.采用3D玻璃毛细管微流控装置连续合成尺寸可控、聚乙烯吡咯烷酮（PVP）稳定的生物相容性金纳米粒子的补充文件。摘要：本研究开发了一种可靠的玻璃毛细管微流控方法，可连续制备由不同分子量聚乙烯吡咯烷酮（PVP K15、PVP K30与PVP K90）包覆的尺寸可控金纳米粒子（AuNPs）。本研究采用注射孔直径介于100~240 μm的两相并流玻璃毛细管微流控装置，通过三氯金酸三水合物（HAuCl₄·3H₂O）与抗坏血酸之间的化学还原反应合成金纳米粒子。经动态光散射（DLS）测试表明，所合成的金纳米粒子平均粒径介于48~135 nm之间。减小注射孔直径、提升抗坏血酸流体的流速及其pH值，均可得到粒径更小的金纳米粒子。研究发现，金纳米粒子的多分散性指数（PDI）与注射孔直径及PVP的分子量无关，但随抗坏血酸流体的流速和pH值升高而增大。为期6周的稳定性研究证实，平均分子量为40000 g/mol的PVP K30是合成并稳定小粒径金纳米粒子的最佳包覆剂。通过十八烷基三甲氧基硅烷对反应装置/毛细管内壁进行疏水改性，以及使用更高pH值的抗坏血酸溶液，可缓解因金纳米粒子沉积在反应装置内壁和孔道内导致的装置结垢问题。