To label or not: the need for validation in label-free imaging.

Significance: Advances in label-free imaging have impacted many areas of biological and biomedical imaging ranging from cell biology and cancer to pathology and neuroscience. Despite the great progress and advantages of these methods, it is clear that to realize their full potential, validation by extrinsic labels and probes is critically needed.

Aim: This perspective calls for developing and applying innovative labels and probes to validate both existing and emerging label-free imaging methods.

Introducing the Special Issue on Label-Free Quantitative Phase Imaging Honoring Prof. Gabriel Popescu, a Pioneer in Biomedical Optics.

The editorial introduces the JBO special issue honoring Prof. Gabriel Popescu, Pioneer in Biomedical Optics.

Real-time imaging reveals a role for macrophage protrusive motility in melanoma invasion.

Macrophages are primary cells of the innate immune system that mediate tumor progression. However, the motile behavior of macrophages and interactions with tumor cells are not well understood. Here, we exploit the optical transparency of larval zebrafish and perform real-time imaging of macrophage-melanoma interactions.

Multi-Modal Investigation of Metabolism in Murine Breast Cancer Cell Lines Using Fluorescence Lifetime Microscopy and Hyperpolarized 13C-Pyruvate Magnetic Resonance Spectroscopy.

: Despite the role of metabolism in breast cancer metastasis, we still cannot predict which breast tumors will progress to distal metastatic lesions or remain dormant. This work uses metabolic imaging to study breast cancer cell lines (4T1, 4T07, and 67NR) with differing metastatic potential in a 3D collagen gel bioreactor system. : Within the bioreactor, hyperpolarized magnetic resonance spectroscopy (HP-MRS) is used to image lactate/pyruvate ratios, while fluorescence lifetime imaging microscopy (FLIM) of endogenous metabolites measures metabolism at the cellular scale.