CAREER: Dual-comb photoacoustic microscopy with super-resolution wavefront shaping

这个CAREER项目将建立第一个用于深层组织高速光谱成像的双梳光声显微镜（DC-PAM）。经过几十年的发展，激光显微镜现在提供了无与伦比的时空分辨率和光学活检能力，其中组织病理学直接在体内进行检查，而无需手术。然而，在显微镜下描绘人体组织深处的细胞结构仍然是一个巨大的挑战。因此，激光显微镜目前仅限于表面成像，其提供对人类组织（例如大脑皮层、内皮和关节软骨）的全面评估的能力受到损害。通过建立一种新的显微镜技术，该项目将实现深层组织成像能力，促进早期疾病诊断和管理。DC-PAM的第一个生物医学应用是针对骨关节炎的早期诊断，这是一个主要的公共卫生问题和经济负担，每年花费1368亿美元。DC-PAM的变革性成像能力也适用于其他生物医学领域，包括手术指导、癌症评估、经颅神经成像和刺激。此外，该项目开发的创新光子和声学技术将为科学界提供新的工具，以应对大气传感和量子光子学的挑战。该项目还旨在培养STEM学生应用光子技术解决现实世界生物医学问题的热情。这一目标将通过几个完全整合的教育和推广活动与整个校园，科罗拉多光子产业协会和光学学会的计划来实现。具体的教育目标是：1）通过CU科学发现计划，让高中生参与暑期研究经验; 2）通过发现学习学徒计划，为本科生提供跨学科研究机会; 3）开发新的讲座/实验室课程，让一年级研究生参与最先进的生物成像和生物传感技术; 4）每年夏天举办社区学院教师合作研究经验交流会，通过美国国家科学基金会资助的ARETe项目共同开发教育性DC-PAM模块，研究目的是将相干光源、器件微细加工和生物仪器等联合收割机理论和技术相结合，建立第一个用于深层组织肌肉骨骼光谱成像的DC-PAM。光声显微镜（PAM）是一种新兴的深层组织显微镜技术，它能够在毫米级深度下实现分子吸收对比度和微米级分辨率的体内成像。双梳光谱（DCS）是一种不断发展的高速光谱方法，其在没有任何机械运动部件的情况下提供具有自校准精度和高灵敏度的多个分子吸收线的并行检测。DC-PAM将独特地结合联合收割机的优势，PAM在成像深度和DCS在成像速度的方式，该技术也弥补了对方的缺点。此外，光学照明波长将扩展到最近确定的第四个近红外窗口，以从根本上减少多重光散射，并利用脂质，胶原蛋白和水的分子特异性。最后，将设计一种超分辨率光声引导波前成形（PAWS）方法，而不采用任何非线性效应，将DC-PAM成像深度远远超过光学扩散极限，同时保持细胞分辨率。具体的研究目标是：1）提出了一种双梳状光源结构，并进行了全面的理论分析和实验表征; 2）研制了双梳状超声检测系统，建立了一种无非线性的超分辨PAWS方法;以及3）验证DC-PAM通过对牛髌骨软骨组织与自然发生的骨关节炎的成像研究。该奖项反映了NSF的法定使命，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价，认为值得支持。

This CAREER project will establish the first dual-comb photoacoustic microscopy (DC-PAM) for deep-tissue high-speed spectro-imaging. After decades of development, laser microscopy now provides unrivaled spatio-temporal resolution and optical biopsy capability, where tissue histopathology is directly examined in vivo without surgical procedure. However, microscopic depiction of cellular structures deep within human tissues remains a grand challenge. Laser microscopy is therefore currently limited to superficial imaging, with compromised capability to provide comprehensive assessment of human tissues such as cerebral cortex, endothelium, and articular cartilage. By establishing a new microscopy technique, this project will enable deep tissue imaging capabilities that facilitate early disease diagnosis and management. The first biomedical application of DC-PAM is to target the early diagnosis of osteoarthritis, a major public health concern and economic burden costing $136.8 billion annually. Transformative imaging capability of DC-PAM is also applicable to other biomedical fields, including surgical guidance, cancer assessment, transcranial neuroimaging and stimulation. Moreover, innovative photonic and acoustic technologies developed in this project will provide the scientific community new tools for addressing challenges in atmospheric sensing and quantum photonics. This project is also aimed at cultivating STEM students’ passion in applying photonic technology to address real-world biomedical problems. The goal will be achieved through several fully integrated educational and outreach activities with programs across the campus, the Colorado Photonics Industry Association, and The Optical Society. The specific education objectives are to: 1) engage high-school students with summer research experience through the CU Science Discovery program; 2) provide interdisciplinary research opportunities to undergraduate students through the Discovery Learning Apprenticeship program; 3) develop a new lecture/lab course to engage first-year graduate students with state-of-the-art bioimaging and biosensing technologies; and 4) host a community college faculty every summer for collaborative research experiences and joint development of educational DC-PAM modules through the NSF funded ARETe program.The research aims to combine theory and technology of coherent light source, device microfabrication, and bioinstrumentation to establish the first DC-PAM for deep-tissue musculoskeletal spectro-imaging. Photoacoustic microscopy (PAM) is an emerging deep-tissue microscopy technique that enables in vivo imaging with molecular absorption contrast and micrometer-scale resolution at millimeter-scale depth. Dual-comb spectroscopy (DCS) is a growing high-speed spectroscopic method that offers parallel detection of multiple molecular absorption lines with self-calibrated precision and high sensitivity in the absence of any mechanical moving part. DC-PAM will uniquely combine the advantages of PAM in imaging depth and DCS in imaging speed in a way that the techniques also compensate for each other’s drawbacks. Further, optical illumination wavelength will be extended to the recently identified fourth near-infrared window to fundamentally reduce the multiple light scattering and use the molecular specificity of lipid, collagen, and water. Finally, a super-resolution photoacoustically guided wavefront shaping (PAWS) method will be devised without employing any nonlinear effect, pushing the DC-PAM imaging depth well beyond optical diffusion limit, while maintaining cellular resolution. Specific research objectives are to: 1) demonstrate a dual-comb light source architecture and undertake a full theoretical analysis and experimental characterization; 2) develop a dual-comb ultrasonic detect system and establish a super-resolution PAWS method without nonlinearity; and 3) validate the DC-PAM through imaging studies on bovine patella cartilage tissues with naturally occurring osteoarthritis.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.