Multimodal label-free microscopy

Abstract

This paper reviews the di®erent multimodal applications based on a large extent of label-free imaging modalities, ranging from linear to nonlinear optics, while also including spectroscopic measurements. We put speci¯c emphasis on multimodal measurements going across the usual boundaries between imaging modalities, whereas most multimodal platforms combine techniques based on similar light interactions or similar hardware implementations. In this review, we limit the scope to focus on applications for biology such as live cells or tissues, since by their nature of being alive or fragile, we are often not free to take liberties with the image acquisition times and are forced to gather the maximum amount of information possible at one time. For such samples, imaging by a given label-free method usually presents a challenge in obtaining su±cient optical signal or is limited in terms of the types of observable targets. Multimodal imaging is then particularly attractive for these samples in order to maximize the amount of measured information. While multimodal imaging is always useful in the sense of acquiring additional information from additional modes, at times it is possible to attain information that could not be discovered using any single mode alone, which is the essence of the progress that is possible using a multimodal approach.

Label‐free multi‐parametric imaging of single cells: dual picosecond optoacoustic microscopy

“…Nevertheless, they typically require the registration and approval of non‐native fluorophores and/or fusion protein tags , which complicate the procedure and may also affect molecular function and cytotoxic free‐radical generation. Tremendous efforts have thus been made in the past decades to develop new imaging modalities that involve no addition of exogenous fluorescent labels or other contrast agents, but use straightforward endogenous characteristics of cells to create imaging contrasts.…”

Multimodal discrimination of immune cells using a combination of Raman spectroscopy and digital holographic microscopy

“…It has been demonstrated that DHM and RS may be implemented simultaneously for determination of both local molecular content and observation of dynamic sample morphology at video rates18, and for determining the relationship between Raman information and quantitative phase information of a cell1920. This technique has also been applied to red blood cells21 where wide field DHM imaging is used as a screening tool to look for morphological features that may indicate malaria infection, and Raman microscopy is used for validation.…”

Digital holography and its multidimensional imaging applications: a review

“…DH also has the ability to simultaneously record an interference fringe image and incoherent light, such as fluorescence and phosphorescence light [ 122 , 123 ]. Fluorescence imaging in biology has proven valuable in detecting certain cells or cell components.…”

“…In order to understand cell activities thoroughly, simultaneous detection of fluorescence and phase information from the same measuring object is desired. Several research groups have proposed single-shot implementations to record fluorescence light and quantitative phase images simultaneously [ 41 , 122 , 123 ]. Quan et al .…”