Applications of NIR-II Imaging Technology

1. Cancer Imaging and Image-Guided Surgery

Some of the significant findings in oncology involved the use of NIR-II probes for tumor visualization and surgical guidance.

Targeted NIR-II fluorescence probes have been developed which are capable of identifying metastatic ovarian cancer with greater accuracy than conventional indocyanine green (ICG)-based imaging. A complementary DNA-mediated self-assembly strategy allows the probes to remain within tumor tissues for approximately six hours, creating an optimal surgical window. This approach enables surgeons to visualize and remove even very small metastatic lesions with:

• Improved tumor margin identification
• Enhanced detection of metastatic lesions
• Greater precision during cancer surgery
• Reduced risk of residual tumor tissue

These benefits can significantly improve surgical outcomes and reduce recurrence rates.

2. Sentinel Lymph Node Detection

Dual NIR-II imaging systems are capable of simultaneously identifying primary tumors and cancer-invaded sentinel lymph nodes.

A combination of donor-acceptor-donor fluorescent probes and PbS quantum dots enables  visualization of both tumors and metastatic lymph nodes with exceptional clarity. Compared with conventional tracers, these probes demonstrate superior photostability, brightness, and imaging quality, providing:

• Non-radioactive alternative to lymphoscintigraphy
• Safer lymph node mapping procedures
• Improved cancer staging
• Better surgical planning

This advancement may reduce dependence on radioactive diagnostic methods currently used in oncology.

3. Stem Cell Tracking in Regenerative Medicine

One of the major applications of NIR-II imaging is to monitor transplanted stem cells.

A multimodal imaging platform combining NIR-II fluorescence imaging with bioluminescence imaging has been developed that successfully track the location, survival, and differentiation of transplanted human mesenchymal stem cells using Ag₂S quantum dots, in real time for up to 30 days. In addition, PbS quantum dots are used to monitor stem cell migration and retention during tendon repair therapy, revealing critical information about treatment effectiveness. The provide:

• Real-time monitoring of stem cell therapies
• Improved treatment optimization
• Enhanced regenerative medicine outcomes
• Better understanding of stem cell behavior inside the body

These capabilities are particularly valuable for treating musculoskeletal injuries, cardiac disease, and tissue regeneration disorders.

4. Smart Drug Delivery and Controlled Drug Release

NIR-II-has also found its application in the therapeutic nanoplatforms designed for precision drug delivery.

A hydrogen sulfide-responsive nanoplatform is capable of releasing anticancer drugs only when activated by NIR light. The system simultaneously provides tumor imaging and controlled drug release, significantly suppressing tumor growth while minimizing side effects.

Researchers have also created PEGylated Indium Selenide (InSe) nanosheets which are capable of causing NIR-II-triggered drug release and photothermal therapy, demonstrating powerful synergistic effects against cancer cells. These have improved:

• Precision cancer treatment
• Reduced systemic toxicity
• Targeted drug activation
• Improved therapeutic outcomes

5. Inflammation Detection and Monitoring

NIR-II imaging has shown remarkable potential for detecting inflammation deep within biological tissues.

An aggregation-induced emission (AIE) nanoprobes capable of crossing the blood-brain barrier and accumulating at sites of brain inflammation has been designed. These probes achieved signal-to-noise ratios significantly higher than traditional imaging agents such as ICG.

A 1550 nm-emitting nanoprobe is designed that enables high-resolution imaging of lymphatic inflammation with exceptional sensitivity and anatomical detail, allowing:

• Early inflammation diagnosis
• Neurological disease monitoring
• Autoimmune disease assessment
• Improved inflammatory biomarker detection

Such capabilities may support earlier intervention in chronic inflammatory conditions.

6. Tumor Blood Vessel Imaging

Tumor angiogenesis plays a crucial role in cancer growth and metastasis. NIR-II imaging enables researchers and clinicians to monitor vascular changes with unprecedented detail.

Nd³⁺-doped nanoprobes are capable of visualizing tumor blood vessel formation, growth, and necrosis. These probes also supported MRI and CT imaging, creating a multimodal diagnostic platform. Clinicians can successfully track vascular changes throughout tumor progression, offering valuable insights into disease development and treatment response. These application aid in:

• Monitoring tumor progression
• Evaluating treatment response
• Supporting cancer staging
• Detecting vascular abnormalities

These applications can enhance both diagnosis and therapeutic decision-making.

Future Insights

Although NIR-II imaging demonstrates enormous promise, several challenges may be addressed before widespread clinical adoption, like:

• Improving probe stability in biological environments
• Enhancing fluorescence quantum yield
• Reducing long-term toxicity risks
• Developing safer and more biodegradable nanoprobes
• Advancing imaging equipment performance and accessibility

Near-Infrared II imaging technology is redefining biomedical detection by offering deeper tissue penetration, higher imaging resolution, and superior diagnostic accuracy. Innovative nanoprobes and advanced imaging strategies that use NIR-II, have demonstrated practical applications ranging from cancer surgery and stem cell tracking to targeted drug delivery and inflammation monitoring. As probe design, safety profiles, and imaging systems continue to improve, NIR-II imaging is positioned to become a cornerstone of next-generation precision medicine and clinical diagnostics.