EAGER: Design and Processing of Anti-microbial Surfaces Using Polymer Extrusion Additive Manufacturing Embedding Silver Nanoparticles with Enhanced Ion Releasing Kinetics

银纳米粒子因其对常见细菌和病毒的强大抗菌能力而在医疗保健应用中颇具吸引力。然而，生产抗菌产品所需的纳米颗粒浓度可能高得令人望而却步。与此同时，添加剂制造在快速生产需要抗菌功能的生物医疗设备和个人防护用品方面显示出巨大的潜力。通过将纳米银引入聚合物长丝中用于材料挤出添加剂制造，通过控制工艺设置和部件几何形状，可以大幅减少抗菌部件所需的纳米颗粒数量，同时仍保持抗菌特性。这一早期概念探索性研究补助金(AGER)奖支持基础研究，这些研究将获得有关纳米银颗粒以及零件的几何和加工条件如何影响离子释放动力学和所制造零件的抗菌能力有效性的知识。研究成果可能会提高在医疗保健应用中减少传染病传播的能力，从而造福社会。该项目还将通过开发一个讲习班，针对路易斯安那州最大的为少数族裔服务的社区学院德尔加多社区学院的学生，为来自代表不足群体的学生提供制造方面的教育。参加研讨会的学生将接触到这个项目的材料，以及先进制造领域的额外教育和研究机会。这项研究的目的是了解添加剂制造工艺和设计如何控制需要抗菌性能的已加工表面上纳米银的浓度。细菌的黏附和生长，以及消除细菌的银离子的释放，不仅取决于表面形貌，还取决于部件的内部空隙。该方法的创新之处在于使用沉积填充图案、层高度和喷嘴尺寸来生产具有以下特征的样品：(I)具有高弯曲表面形貌的样品，其限制了有利的附着位置并限制了表面细菌的生长；(Ii)在不牺牲其他成分性能的情况下增加了内部空隙，从而在部分表面获得了更高的抗菌银离子释放率。跨学科研究小组将分别通过光学和电子显微镜、质谱学和抗菌素分析对标本形态、银离子释放率以及常见细菌大肠杆菌和金黄色葡萄球菌的黏附和生长进行表征，以检验这些结果。该项目将更好地了解添加剂制造工艺和设计参数如何影响抗菌机制，这些机制可用于为广泛的成本效益医疗应用开发设计战略，可用于限制感染率。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Silver nanoparticles are appealing for healthcare applications because of their strong antimicrobial ability against common bacteria and viruses. However, the concentration of nanoparticles needed to manufacture antimicrobial products can be prohibitively costly. Meanwhile, additive manufacturing has shown great potential for the rapid production of biomedical devices and personal protective equipment that desire an antimicrobial function. By incorporating silver nanoparticles into polymer filaments for material extrusion additive manufacturing, the nanoparticle quantity needed for antimicrobial parts may be substantially reduced through controlling processing settings and part geometry, while still maintaining antimicrobial characteristics. This EArly-concept Grants for Exploratory Research (EAGER) award supports fundament research that will gain knowledge on how silver nanoparticles incorporated as well as part geometric and processing conditions may influence ion releasing kinetics and the effectiveness in antimicrobial ability of fabricated parts. The research outcomes may potentially improve the ability to reduce the spread of infection diseases in medical care applications and thus benefit the well-being of the society. This project will also contribute to the education in manufacturing for students from underrepresented groups through the development of a workshop that targets students from Delgado Community College, the largest minority-serving community college in Louisiana. Students attending the workshop will gain exposures to the materials of this project and additional education and research opportunities in advanced manufacturing areas.The objective of this research is to understand how additive manufacturing processing and designs govern the concentration of silver nanoparticles on fabricated surfaces that require antimicrobial properties. The adhesion and growth of bacteria and the release of silver ions that eradicate bacteria depend not only on surface topography but also the internal voids of a part. The novelty of the approach lies upon employing deposition infill patterns, layer heights, and nozzle sizes to produce specimens with (i) surface topography with high tortuosity that limits favorable attachment sites and confines the growth of surface bacteria, and (ii) increased internal voids, while without sacrificing other component performance, for a higher release rate of antimicrobial silver ions at part surfaces. The interdisciplinary research team will test these outcomes by characterization of specimen morphologies, silver ion release rates, and the adhesion and growth of the common bacteria Escherichia coli and Staphylococcus aureus by optical and electron microscopy, mass spectrometry, and antimicrobial assays, respectively. The project will offer a better understanding of how additive manufacturing processing and design parameters influence the antimicrobial mechanisms, which can be used to develop design strategies for a wide range of cost-effective healthcare applications that can be used to limit infection rates.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.