Hyperspectral imaging of nanoparticles in biological samples: Simultaneous visualization and elemental identification

Area of Science:

• Nanomaterial safety assessment
• Advanced imaging techniques
• Toxicological studies

Background:

• Engineered nanomaterials (ENMs) are widespread, but their biological effects are unknown.
• Current methods for ENM detection in biological samples, like electron microscopy (EM), are time-consuming and resource-intensive.
• Novel, faster visualization techniques are needed to identify and locate ENMs in complex biological matrices.

Purpose of the Study:

• To evaluate enhanced dark-field hyperspectral imaging (EDFM-HSI) for locating, identifying, and mapping metal oxide ENMs in ex vivo porcine skin.
• To compare the efficacy of EDFM-HSI mapping with conventional methods such as Raman spectroscopy (RS), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM).

Main Methods:

• Utilized EDFM-HSI to capture spectral data (400-1000 nm) from each pixel in porcine skin tissue samples containing metal oxide ENMs.
• Generated hyperspectral maps to visualize the presence and location of ENMs within the tissue.
• Validated EDFM-HSI findings against conventional techniques (RS, EDS, SEM).

Main Results:

• EDFM-HSI mapping effectively located and identified metal oxide ENMs in histological porcine skin samples.
• The results from EDFM-HSI were confirmed by conventional analytical methods (RS, EDS, SEM).
• Hyperspectral mapping proved crucial for distinguishing ENM morphology from surrounding tissue structures.

Conclusions:

• EDFM-HSI mapping is a viable, novel technique for identifying and locating ENMs in biological samples.
• This method offers a higher throughput alternative to traditional techniques for ENM analysis.
• Further development of EDFM-HSI holds promise for the semiquantitation of ENMs in biological tissues.