Tunable and Enhanced NIR-II Luminescence from Heavily Doped Rare-Earth Nanoparticles for In Vivo Bioimaging

Nanomaterials for light-mediated therapeutics in deep tissue

Light-mediated therapeutics, including photodynamic therapy, photothermal therapy and light-triggered drug delivery, have been widely studied due to their high specificity and effective therapy. However, conventional light-mediated therapies usually depend on the activation of light-sensitive molecules with UV or visible light, which have poor penetration in biological tissues. Over the past decade, efforts have been made to engineer nanosystems that can generate luminescence through excitation with near-infrared (NIR) light, ultrasound or X-ray. Certain nanosystems can even carry out light-mediated therapy through chemiluminescence, eliminating the need for external activation. Compared to UV or visible light, these 4 excitation modes penetrate more deeply into biological tissues, triggering light-mediated therapy in deeper tissues. In this review, we systematically report the design and mechanisms of different luminescent nanosystems excited by the 4 excitation sources, methods to enhance the generated luminescence, and recent applications of such nanosystems in deep tissue light-mediated therapeutics.

Preparation of rare earth-doped nano-fluorescent materials in the second near-infrared region and their application in biological imaging

Second near-infrared (NIR-II) fluorescence imaging (FLI) has gained widespread interest in the biomedical field because of its advantages of high sensitivity and high penetration depth. In particular, rare earth-doped nanoprobes (RENPs) have shown completely different physical and chemical properties from macroscopic substances owing to their unique size and structure. This paper reviews the synthesis methods and types of RENPs for NIR-II imaging, focusing on new methods to enhance the luminous intensity of RENPs and multi-band imaging and multi-mode imaging of RENPs in biological applications. This review also presents an overview of the challenges and future development prospects based on RENPs in NIR-II regional bioimaging.

Novel Self-Assembled Multifunctional Nanoprobes for Second-Near-Infrared-Fluorescence-Image-Guided Breast Cancer Surgery and Enhanced Radiotherapy Efficacy

Breast-conserving surgery (BCS) is the predominant treatment approach for initial breast cancer. However, due to a lack of effective methods evaluating BCS margins, local recurrence caused by positive margins remains an issue. Accordingly, radiation therapy (RT) is a common modality in patients with advanced breast cancer. However, while RT also protects normal tissue and enhances tumor bed doses to improve therapeutic effects, current radiosensitizers cannot meet these urgent clinical needs. To address this, a novel self-assembled multifunctional nanoprobe (NP) gadolinium (Gd)-diethylenetriaminepentaacetic acid-human serum albumin (HSA)@indocyanine green-Bevacizumab (NPs-Bev) is synthesized to improve the efficacy of fluorescence-image-guided BCS and RT. Fluorescence image guidance of the second near infrared NP improves complete resection in tumor-bearing mice and accurately discriminates between benign and malignant mammary tissue in transgenic mice. Moreover, targeting tumors with NPs induces more reactive oxygen species under X-ray radiation therapy, which not only increases RT sensitivity, but also reduces tumor progression in mice. Interestingly, self-assembled NPs-Bev using HSA, the magnetic resonance contrast agent and Bevacizumab-targeting vascular growth factor A, which are clinically safe reagents, are safe in vitro and in vivo. Therefore, the novel self-assembled NPs provide a solid precision therapy platform to treat breast cancer.