Synthesis and Evaluation of Nano-antioxidants for Medical Applications

描述（由申请人提供）：据报道，抗氧化剂有助于预防多种人类疾病，包括癌症和心血管疾病、神经退行性疾病、肺病和慢性病。通常可用的抗氧化剂是小分子量化合物，具有中和自由基的能力，破坏潜在的自由基形成物质，增强免疫系统和表现出对人体健康有益的其他生物活性。对于分子量为数千的大抗氧化剂分子，我们所知甚少。更具体地说，树突状抗氧化剂的生物学效应以前没有报道过。这种应用涉及到抗氧化树突状大分子的合成，它由许多抗氧化剂组成，它们以树突状的方式相互连接，这样它们就能有效地清除自由基。纳米抗氧化分子将由二羟基苯甲醛和丙胺分支单元以重复的方式合成，以得到定义明确和精确的树状大分子。据推测，这种独特的抗氧化结构将显示出协同效应，并揭示出一些有趣和有益的特性，如改善水溶性和稳定性，增强自由基清除能力。这些纳米粒子与生物分子有更强的相互作用，因此比小分子抗氧化剂对自由基损伤有更好的保护。这些新型纳米材料将通过多种化学和生物分析技术进行表征，包括聚丙烯酰胺凝胶电泳、高效液相色谱、光谱和质谱分析。它们的抗氧化能力将通过电子自旋共振和光谱分析来测量，并与对照进行比较，如它们的单体对应物（构建块）和常见的抗氧化剂，如维生素C和e。抗氧化树突状物保护DNA、脂质、蛋白质和红细胞的能力将在体外自由基生成系统中测定，并与小分子抗氧化剂进行比较。DNA链断裂将通过琼脂糖凝胶电泳测定。蛋白质损伤将通过荧光光谱、反相高效液相色谱、粒径排除色谱和凝胶电泳进行监测。脂质过氧化将通过紫外分光光度法监测二烯的形成来测量，而细胞损伤将通过红细胞溶血来评估。这些研究将为纳米抗氧化剂对生物分子和细胞的保护作用提供宝贵的数据。此外，所提出的抗氧化树状大分子将为制备用于疾病检测、诊断和治疗的多功能纳米器件提供一个独特的平台。公共卫生相关性：该应用将涉及抗氧化树突状大分子的合成，并研究其清除自由基的能力及其对生物分子和细胞的影响。这项研究的结果将有利于利用纳米抗氧化剂来预防、检测、诊断和治疗与氧化应激密切相关的人类疾病，包括癌症、心血管疾病、慢性炎症和神经退行性疾病。

DESCRIPTION (provided by applicant): Antioxidants have been reported to be beneficial for prevention of a variety of human diseases including cancer and cardiovascular, neurodegenerative, pulmonary and chronic ailments. Commonly available antioxidants are small molecular weight compounds that have the ability to neutralize free radicals, destroy potential radical forming substances, boost the immune system and exhibit other biological activities that are beneficial to human health. Little is known about large antioxidant molecules with molecular weights in the thousands. More specifically, the biological effects of dendritic forms of antioxidants have not been reported before. This application involves the synthesis of antioxidant dendrimers composed of numerous units of antioxidants connected to one another in a tree like fashion so that they can effectively scavenge free radicals. The nano-antioxidant molecules will be synthesized with dihydroxybenzaldehyde building blocks and propargylamine branching units in a reiterative manner to give well-defined and precise dendrimers. It is hypothesized that this unique antioxidant architecture will display cooperative effects and reveal some interesting and beneficial properties such as improved aqueous solubility and stability and enhanced radical scavenging potency. It is also believed that these nano-particles will have stronger interactions with biomolecules and therefore be better protectants than small molecule antioxidants against free radical damage. These novel nano-materials will be characterized by a number of chemical and bio-analytical techniques including polyacrylamide gel electrophoresis, HPLC, spectroscopy and mass spectrometry. Their antioxidant potency will be measured with electron spin resonance and spectroscopic assays and compared to controls, such as their monomeric counterparts (building block) and common antioxidants like vitamins C and E. The ability of the antioxidant dendrimers to protect DNA, lipids, proteins and red blood cells will be determined in a free radical generating system in vitro and compared to small molecule antioxidants. DNA strand breakage will be determined by agarose gel electrophoresis. Protein damage will be monitored by fluorescence spectroscopy, reversed phase HPLC, size exclusion chromatography, and gel electrophoresis. Lipid peroxidation will be measured by monitoring diene formation with ultraviolet spectrophotometry while cell damage will be evaluated by red blood cell hemolysis. These studies should provide invaluable data towards the protective effects of nano-antioxidants on biomolecules and cells. In addition, the proposed antioxidant dendrimer will provide a unique platform for preparing multifunctional nano-devices for detection, diagnosis and treatment of diseases. PUBLIC HEALTH RELEVANCE: This application will involve the synthesis of antioxidant dendrimers and investigate their free radical scavenging potency as well as their effects on biomolecules and cells. Results of this study will benefit the use of nano-antioxidants for prevention, detection, diagnosis and treatment of human diseases that have a strong association with oxidative stress including cancer, cardiovascular diseases, and chronic inflammatory and neurodegenerative diseases.