Enzyme-activated Nanoparticles as Contrast Agents for Optical Detection of Cancer

描述(申请人提供)：尽管在过去的几十年里癌症的检测有了很大的进步，但非侵入性的早期检测仍然是一个挑战。光学成像是一种提供高时空分辨率、毫米成像深度、组织或造影剂信号的光谱分辨率以及允许在医生办公室或手术室实时使用的相对简单的方式。尽管有这些优点，但由于正常组织和癌组织之间缺乏光学对比度，它在检测发展中的肿瘤方面的应用受到限制。在目前的提案中，InnoSense LLC的目标是开发可注射的、长时间循环的、有针对性的酶激活纳米颗粒(EANPs)，并在体外和体内进行初步评估，这些纳米颗粒作为癌症特异性造影剂，用于非侵入性肿瘤光学成像。这些纳米颗粒基于已证实的生物兼容和可生物降解的聚合物，将包含猝灭的近红外(NIR)荧光分子，这些分子在与肿瘤组织中过度表达的靶酶相互作用时被激活。通过利用增强的渗透性和滞留效应，允许纳米颗粒在肿瘤组织中积累，以及通过加入针对癌症生物标记物的抗体，这些纳米颗粒对肿瘤的特异性将得到提高。利用纳米粒子改善荧光分子对肿瘤的生物分布和有效载荷，结合肿瘤特异性酶引发的近红外信号的产生，有望导致与其他造影剂系统相比显著提高信号背景水平，从而提高非侵入性光学检测的特异性和灵敏度。抗体缺失和抗体结合的EANPs的生物相容性和特异性将在正常细胞和癌细胞中进行体外评估。光学对比度增强将作为纳米颗粒配方、组织模体和癌症动物模型中浓度和深度的函数进行评估。该项目将与加州大学欧文分校生物医学工程系助理教授Bernard Choi博士和Beckman激光研究所合作进行。在第一阶段可行性研究完成后，第二阶段项目将集中于优化EANP的制备、重复性和放大，并在癌症动物模型中进行严格评估，以确定最佳剂量、近红外显影时间以及可实现的成像深度和空间分辨率。 与公共卫生相关：尽管在过去的几十年里，癌症的检测有了很大的进步，但非侵入性的肿瘤早期检测仍然是一个挑战。光学成像是一种提供高空间和时间分辨率的方式，能够从组织或造影剂中检测和分离信号，成像深度为毫米，并且相对简单，可以在医生的办公室或手术室使用。尽管有这些优点，但由于正常组织和癌组织之间的低对比度，它在检测发展中的肿瘤方面的应用受到限制。在目前的提案中，InnoSense LLC旨在开发和评估可注射的、长时间循环的、有针对性的酶激活纳米颗粒(EANPs)，这些纳米颗粒作为癌症特异性造影剂，用于肿瘤的非侵入性光学成像。基于已证实的无毒聚合物的EANP将包含休眠的荧光分子，当与肿瘤组织中高水平存在的酶分子相互作用时，这些分子会被激活。EANP的高有效载荷，加上它们由癌症触发的激活，将导致高信号背景水平，从而提高光学检测的灵敏度。这项研究不仅将为癌症组织的非侵入性成像开发一种安全有效的选择，而且还将进一步巩固基于纳米颗粒的造影剂和生物材料领域的科学知识。

DESCRIPTION (provided by applicant): Despite great improvements in the detection of cancer in the last few decades, non-invasive early detection is still a challenge. Optical imaging is a modality that offers high spatio-temporal resolution, millimeters in depth of imaging, spectral resolution of tissue or contrast agent signals, and relative simplicity that would permit its use in real time at a physician's office or operating room. Despite these benefits, its application to the detection of developing tumors is limited due to the lack of optical contrast between normal and cancerous tissue. In the present proposal, InnoSense LLC aims to develop and perform preliminary in vitro and in vivo evaluation of injectable, long-circulating, targeted enzymatically-activated nanoparticles (EANPs) that act as cancer-specific contrast agents for non-invasive optical imaging of tumors. These nanoparticles, based on proven biocompatible and biodegradable polymers, will contain quenched near infra- red (NIR) fluorescent molecules that are activated upon interaction with target enzymes that are overexpressed in tumor tissue. The specificity of these nanoparticles to tumors will be increased by taking advantage of the enhanced permeability and retention effect that permits accumulation of nanoparticles at tumor tissue, and by the incorporation of antibodies specific to cancer biomarkers. The use of nanoparticles to improve the biodistribution and payload of the fluorescent molecules to tumors, combined with the cancer-specific enzyme-triggered development of NIR signal is expected to result in significantly increased signal-to-background levels in comparison to other contrast agent systems, thus improving the specificity and sensitivity of non-invasive optical detection. The biocompatibility and specificity of antibody- lacking and antibody-bound EANPs will be evaluated in vitro in normal and cancer cells. Optical contrast enhancement will be evaluated as a function of nanoparticle formulation, concentration and depth in tissue phantoms and in animal models of cancer. This project will be performed in collaboration with Dr. Bernard Choi, Assistant Professor of the Department of Biomedical Engineering and the Beckman Laser Institute of the University of California, Irvine. Upon completion of the Phase I feasibility study, a Phase II project will center on the optimization of EANP preparation, reproducibility, and scale up, and rigorous evaluation in animal models of cancer to determine optimal dose, NIR development time, and achievable imaging depth and spatial resolution. PUBLIC HEALTH RELEVANCE: Despite great improvements in the detection of cancer in the last few decades, non-invasive early detection of tumors is still a challenge. Optical imaging is a modality that offers high spatial and temporal resolution, the ability to detect and separate signals from tissue or contrast agents, millimeters in depth of imaging, and relative simplicity that would permit its use at a physician's office or operating room. Despite these benefits, its application to the detection of developing tumors is limited due to the low contrast between normal and cancerous tissue. In the present proposal, InnoSense LLC aims to develop and evaluate injectable, long-circulating, targeted enzymatically-activated nanoparticles (EANPs) that act as cancer-specific contrast agents for non-invasive optical imaging of tumors. EANPs, based on proven non-toxic polymers, will contain dormant fluorescent molecules that are activated upon interaction with enzyme molecules that are present in high levels in tumor tissue. The high payload of EANPs, together with their cancer-triggered activation will lead to high signal-to-background levels that improve the sensitivity of optical detection. This research will not only result in the development of a safe and effective option for non-invasive imaging of cancerous tissue, but will also further the body of scientific knowledge in the area of nanoparticle-based contrast agents and biomaterials.