Exploring the Syntheses and Biomedical Applications of Nanoparticles: Simple Activities and Demonstrations for Middle and Early High School Students

Nanoparticles (NPs) can exhibit unique properties distinct from their bulk counterparts. This has led to their utilization in many fields; most notably, they have been implemented in numerous biomedical applications. Given the significance of these applications, introducing students to nanoscience early can be highly beneficial. This paper outlines an outreach activity designed as an introduction to nanoscience for middle and early high school students, focusing on two of the most widely studied NPs in biomedicine: magnetic iron oxide nanoparticles (IONPs) and gold nanoparticles (Au NPs). The 2 h teaching session consists of four parts: two synthesis demonstrations and two interactive activities, using only nonspecialized apparatus and cost-effective materials. In the first demonstration, Au NPs are synthesized through chemical reduction of an Au salt, employing lemon juice as a reducing agent. The subsequent activity employs these NPs in an exhibition of colorimetric sensing. In the second demonstration, IONPs are synthesized through coprecipitation. Finally, the students employ ferrofluids to visualize the magnetic interactions that take place when IONPs come into proximity of a magnetic field. A series of learning goals are outlined, with assessment through in-session questions and a feedback session. The activity has been successfully implemented at an outreach event, where each section was well-received. Student responses to the questions and feedback showed strong engagement and indicated a clear understanding of basic nanoscience concepts, including NP properties, synthesis, and biomedical relevance, particularly for Au NPs and IONPs.纳米颗粒（Nanoparticles，NPs）可展现出与其块体材料截然不同的独特性质，这使其在诸多领域得到应用，尤以生物医学领域的应用最为突出。鉴于此类应用的重要性，尽早向学生普及纳米科学知识极具价值。本文介绍了一项面向初中及高中低年级学生的纳米科学入门科普活动，聚焦生物医学领域研究最为广泛的两类纳米颗粒：磁性氧化铁纳米颗粒（magnetic iron oxide nanoparticles，IONPs）与金纳米颗粒（gold nanoparticles，Au NPs）。本次2小时的教学环节包含四个部分：两场合成演示与两项互动活动，全程仅使用通用实验器材及经济实惠的材料。第一场演示中，以柠檬汁作为还原剂，通过金盐的化学还原法合成金纳米颗粒；后续的互动活动则利用此类纳米颗粒开展比色传感展示。第二场演示中，通过共沉淀法合成磁性氧化铁纳米颗粒；最后，学生将借助磁流体可视化展示磁性氧化铁纳米颗粒置于磁场附近时产生的磁相互作用。本次活动设定了一系列学习目标，并通过课堂提问与反馈环节进行效果评估。该活动已在一场科普推广活动中成功落地，各环节均获得良好反响。学生的课堂作答与反馈显示，他们参与度极高，且清晰掌握了纳米科学的基础概念，包括纳米颗粒的性质、合成方法及其生物医学应用价值，尤以金纳米颗粒与磁性氧化铁纳米颗粒相关内容的掌握效果为佳。