Light forces the pace: optical manipulation for biophotonics

Abstract

Abstract. The biomedical sciences have benefited immensely from photonics technologies in the last 50 years. This includes the application of minute forces that enable the trapping and manipulation of cells and single molecules. In terms of the area of biophotonics, optical manipulation has made a seminal contribution to our understanding of the dynamics of single molecules and the microrheology of cells. Here we present a review of optical manipulation, emphasizing its impact on the areas of single-molecule studies and single-cell biology, and indicating some of the key experiments in the fields.

Analysis of laser-induced heating in optical neuronal guidance

“…A curious new addition to the field of neuronal guidance is optical neuronal guidance (Carnegie et al, 2008(Carnegie et al, , 2009Ehrlicher et al, 2002;Graves et al, 2009;Higuchi et al, 2005Higuchi et al, , 2007Mohanty et al, 2005;Stevenson et al, 2006;Mathew et al, 2010;Koch et al, 2004) reviewed in Franze and Guck (2010) and Stevenson et al (2010). In 1991 it was first observed that Swiss 3T3 cells (mammalian fibroblast-like cells) would extend pseudopodia towards near-infrared light sources (Albrecht-Buehler, 1991), and in 2002 it was shown that a near-infrared laser spot placed on and in front of the leading edge of growing PC12 and NG108 neurons enhanced the neuronal growth into the laser spot and resulted in laser-guided turns of the growth cone and increased growth speed (Ehrlicher et al, 2002).…”

“…medical and research applications, however the biophysical mechanism underlying the phenomenon is not understood as stated in recent studies and reviews: "Notably, the underlying mechanisms responsible for the light-cell interactions described above, have not been fully understood or are not known" (Mathew et al, 2010), "The underlying mechanisms of all these physical guidance cues remain unclear" (Franze and Guck, 2010), and "These experiments are surprising, and the underlying mechanisms are not fully understood" (Stevenson et al, 2010). The experimental studies of optical neuronal guidance reported in the literature (briefly summarized below and in Table 1) have all been sought explained in terms of biophysical mechanisms only involving different forms of optical gradient forces (acting either directly on the actin polymerization mechanism or on the filopodia itself), while neglecting temperature effects from laser-induced heating.…”

Miniaturized optoelectronic tweezers controlled by GaN micro-pixel light emitting diode arrays

“…There are many competing micromanipulation techniques being actively researched, including mechanical manipulation using AFM tips [1], optical tweezers [2], dielectrophoresis [3], magnetic traps [4] and acoustic traps [5]. Each technique has distinct advantages and disadvantages, in terms of the degree of force that can be applied or the precision of the particle manipulation.…”

Special Section Guest Editorial: Selected Topics in Biophotonics: Optical Coherence Tomography and Biomolecular Imaging with Coherent Raman Scattering Microscopy

“…These invited papers provide a natural continuation to previous tutorial papers on the foundation of diffuse optics, 2 imaging thick tissues with diffuse optics, 3 molecular imaging, 4 optical micromanipulation 5 and photodynamic therapy 6 published in special sections from previous schools. These papers all belong to a planned series of tutorial review papers from each biennial school that provide high-level, open-access educational material for the benefit of the scientific community and, in addition, fulfill our own motivation for creating the school in the first place.…”