RUI: Liposome Bilayer-Embedded Hydrophobic Palladium Nanoparticles for Selective Catalytic Reactions in Water

模仿酶功能的分子多年来一直引起人们的兴趣。与天然酶相比，酶模拟物具有易于修改结构、提高稳定性和降低成本的优点。模拟天然酶的化学反应性需要保持酶活性位点及其附近的复杂结构的模型，因为这些位点负责反应性。在这个项目中，加州州立大学长滩分校的Shon博士正在研究一种新的酶模拟方法，将钯纳米颗粒嵌入脂质体的脂质层中，脂质体类似于细胞膜。纳米粒子的表面反应性是通过附着各种分子来修饰的。由此产生的结构可以提供模拟酶活性位点相互作用所需的控制水平。他积极参与建立在他的研究基础上的教育项目和推广活动，以促进从高中生到科学、技术、工程和数学（STEM）学科的硕士研究生的参与。这些活动包括针对本科生的凯克能源和材料计划（KEMP），以及针对高中生的Shon博士实验室夏季材料研究实习。在化学系化学催化项目的资助下，加州州立大学长滩分校（CSULB）的Shon博士正在研究纳米颗粒脂质体的包埋、脂质相变、膜流动性、表面配体密度和纳米颗粒的组成如何影响底物和纳米颗粒之间的非共价相互作用，并决定脂质体双层包埋钯纳米颗粒的催化性能。为了研究脂质体包封的影响，采用不同的脂质体来研究不同的相变温度对包封效果的影响。通过改变钯纳米粒子与脂质摩尔比，观察膜流动性的影响。催化钯纳米颗粒具有可控制的核心尺寸和不同的盖层配体密度和结构，用于将表面配体的影响与纳米颗粒大小、形状、形态和脂质体结构等其他因素隔离开来。了解双硫代酸盐配体在钯纳米颗粒催化剂表面吸附的表面组成和分布的影响，可以区分和控制盖层配体的电子和几何贡献。最终，这些发现将应用于基于药物前活化和生物正交酶反应的优化脂质-纳米颗粒混合治疗剂的开发。他积极从事STEM教育，让本科生和硕士研究生参与创造性的科学研究调查。他积极招募女性和少数族裔学生，这些群体传统上在STEM领域的代表性不足，以促进研究和教育的平衡发展。他还扩大了一个高中生研究实习项目，以支持该项目产生更广泛的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Molecules that mimic the function of enzymes have been of interest for many years. Enzyme mimics provide advantages over natural enzymes as they are easily modified structures, improve stability, and lower cost. Mimicking the chemical reactivity of natural enzymes requires models that maintain the complex structures at and near the enzyme active site as these sites are responsible for that reactivity. In this project, Dr. Shon of California State University Long Beach is investigating a new approach to enzyme mimics where palladium nanoparticles are embedded in the lipid layer of a liposome, which resembles a cell membrane. The nanoparticle surface reactivity is modified by the attachment of various molecules to it. The resulting constructs may provide the level of control needed to simulate the interactions at an enzyme active site. Dr. Shon is actively engaged in educational programs and outreach activities that build upon his research to promote engagement of students ranging from high school students to master-level graduate students in science, technology, engineering and mathematics (STEM) disciplines. These activities include the Keck Energy and Materials Program (KEMP) for undergraduates and summer materials research internships in Dr. Shon’s laboratory for high school students. With funding from the Chemical Catalysis Program of the Division of Chemistry, Dr. Shon of California State University Long Beach (CSULB) is developing a fundamental understanding of how nanoparticle liposome embedding, lipid phase transition, membrane fluidity, and surface ligand density and composition of nanoparticles influence the non-covalent interactions between substrates and nanoparticles and determine the catalytic properties of the liposome bilayer-embedded palladium nanoparticles. For the investigation of the influence of liposome encapsulation, various lipids are used to study the effects of different phase transition temperatures. The molar ratio of lipids to palladium (Pd) nanoparticles are varied to observe the influence of membrane fluidity. Catalytic Pd nanoparticles with controlled core size and varying capping ligand density and structure are used for isolating the effect of surface ligands from other factors such as nanoparticle size, shape, and morphology and liposome structure. Understanding the effects of the surface composition and distribution of binary thiolate ligands adsorbed on Pd nanoparticle catalyst surfaces may distinguish and control the electronic and geometric contributions by the capping ligands. Ultimately, the findings are applied to the development of optimized lipid-nanoparticle hybrid therapeutic agents based on pro-drug activation and bioorthogonal enzymatic reaction. Dr. Shon is actively engaged in STEM education by exposing undergraduate and master's-level graduate students to the creative scientific research investigations. He actively recruits women and minority students, traditionally underrepresented groups in the STEM fields, to enhance the balanced advancement of research and education. He is also expanding a high school student research internship program in support of the broader impacts of the project.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.