A Dual‐Modal Magnetic Resonance/Photoacoustic Imaging Tracer for Long‐Term High‐Precision Tracking and Facilitating Repair of Peripheral Nerve Injuries

Abstract

Neuroanatomical tracing is considered a crucial technique to assess the axonal regeneration level after injury, but traditional tracers do not meet the needs of in vivo neural tracing in deep tissues. Magnetic resonance (MR) and photoacoustic (PA) imaging have high spatial resolution, great penetration depth, and rich contrast. Fe 3 O 4 nanoparticles may work well as a dual-modal diagnosis probe for neural tracers, with the potential to improve nerve regeneration. The present study combines antegrade neural tracing imaging therapy for the peripheral nervous system. Fe 3 O 4 @COOH nanoparticles are successfully conjugated with biotinylated dextran amine (BDA) to produce antegrade nano-neural tracers, which are encapsulated by microfluidic droplets to control leakage and allow sustained, slow release. They have many notable advantages over traditional tracers, including dual-modal real-time MR/PA imaging in vivo, long-duration release effect, and limitation of uncontrolled leakage. These multifunctional anterograde neural tracers have potential neurotherapeutic function, are reliable and may be used as a new platform for peripheral nerve injury imaging and treatment integration.

Multimodal optoacoustic imaging: methods and contrast materials

“…198 The dual-modal agents have been utilized for enhanced visualization of tumors, thrombi, stem cells, and nerve injuries, to name a few representative examples. 31,44,194…”

Microfluidic Manipulation for Biomedical Applications in the Central and Peripheral Nervous Systems

“…These tracers were wrapped by microfluidic droplets to control leakage and allow for continuous and slow release. In addition, these multi-functional anterograde neural tracers had potential neural neurotherapeutic functions and could be used as a new platform for the integration of imaging and the treatment of peripheral nerve injuries [ 103 ]. Therefore, drug-delivery carriers engineered with microfluidic platforms have immense potential for future clinical applications.…”

Photoactivated Nanohybrid for Dual-Nuclei MR/US/PA Multimodal-Guided Photothermal Therapy

“…Activatable theranostics provide advanced solutions for tumor diagnosis by enhancing contrast in various imaging technologies and tailored therapy. − With more diagnostic information, multimodal imaging can diagnose tumors more accurately than single imaging. − So far, positron emission computed tomography (PET)/CT and PET/magnetic resonance imaging (MRI) have been extensively used in the biomedical field, which facilitate the fabrication of multiple responsive and multimodal contrast agents for tumor diagnosis. In addition, there is an urgent need to combine various excellent imaging methods such as MRI, ultrasonic imaging (USI), and photoacoustic imaging (PAI) to develop multimodal imaging methods for the early diagnosis of malignant tumors. − 1 H MRI with excellent spatial resolution and unlimited penetration depth can aid in detecting deep-seated cancers but is hampered by high background signals from normal tissues and low sensitivity. − As a vibrant complementary method, 19 F MRI without background signal and hyperpolarized 129 Xe MRI with ultrahigh sensitivity have received intense attention. − Specifically, hyperpolarized 129 Xe MRI has been applied to evaluate pulmonary function in COVID-19 patients …”