报告人：Prof. Hao Cheng, Drexel University
报告题目：Dynamic topographical structure: A new parameter for designing nanomedicine
报告时间：10：00 AM,Sep 3rd(Tuesday)
Abstract: Nanomaterials have broad biomedical applications. Although their physicochemical properties such as shape, size, elasticity and surface chemical composition are known to be pivotal in the design of nanomedicines. The impact of dynamic topographical structure of nanomaterials has not been studied. In this talk, I will show the importance of this new parameter for nanomedicine design. We have found that nanomaterials blood circulation time could be dramatically extended by controlling the dynamic topographical structure of polyethylene glycol (PEG) shell on nanoparticles. Regular high density PEG shell does not have this effect. Surprisingly, our studies reveal that the dynamic effect extends nanoparticle blood circulation via reduced nanoparticle uptake by liver sinusoidal endothelial cells (LSECs) instead of macrophages. The dynamic PEG layers reduce protein binding affinity to nanoparticles. This property can be used to enhance nanoparticle penetration in mucus. One of the major challenges of nanomedicines in cancer therapy is the inefficient diffusion of drug nanocarriers in solid tumors due to the high density of extracellular matrix in tumors. One old strategy is to conjugate matrix degrading enzymes on nanoparticle surfaces as the enzymes remove barriers for nanoparticle diffusion. However, successful animal studies have not been demonstrated. One reason is the conjugation of bioactive molecules on nanoparticle surfaces often reduces their blood circulation. We show that the problem can be circumvented by embedding matrix degrading enzymes in the PEG shell with dynamic structure instead of presenting the enzymes on the outmost surface of nanoparticles. The effects of prolonged nanoparticle blood circulation and enhanced diffusion in solid tumors dramatically increased nanoparticle accumulation and penetration in tumors, leading to a highly efficient antitumor efficacy. Thus, our platform technology of controlling topographical structure of nanocarriers may be valuable to enhance the clinical efficacy of a broad range of drug nanocarriers. In addition, I will briefly discuss our study on using nanoparticles to induce antigen-specific immune tolerance for treating autoimmune diseases.
成昊博士是美国德雷塞尔大学材料科学与工程系副教授。1999和2001年清华大学化学工程专业本科和硕士毕业， 2005年获美国西北大学材料科学与工程博士学位。作为博士后，2006年到2012年间分别在西北大学和麻省理工学院从事癌症生物学和生物材料的研究。成昊博士的实验室致力于延长纳米颗粒体内循环时间，应用细胞膜作为凝胶材料，以及自身免疫性疾病等方面的研究而。作为通讯作者，他已在ACS Nano，Nano Letters，Nature Communications和 Advanced Drug Delivery Reviews 等期刊上发表了多篇论文。获得了国际知名期刊Nano Research首届纳米研究青年创新者奖。
Contact: Prof. Zhuang Liu