1. Label-free Imaging and Bending Analysis of Microtubules by ROCS Microscopy and Optical Trapping 
Matthias D. Koch, Alexander Rohrbach 
Biophysical Journal 
Volume 114, Issue 1, Pages (January 2018)
DOI: /j.bpj
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2. Figure 1
Schematic of dark-field ROCS technique at λROCS = 532 nm (blue) and integration of optical tweezers with BFP tracking at λOT = 1064 nm (red). See Materials and Methods for a technical description. (Top-left inset) Shown here are time-multiplexed interferometric position signals from a quadrant photodiode (QPD) showing the response of two trapped beads (actor and sensor) connected by a microtubule and actuated at different AOD displacement frequencies ωa. (Top-right inset) Shown here is the angular distribution of scattered light Isca(θ, ki) from oblique incident directions αi = ±60° (blue) and αi = 0° (green). (Bottom-right inset) Given here is an ROCS image of a dense MT dilution at an exposure time T = 100 ms (see also movies in the Supporting Material). Scale bars, 5 μm. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions

3. Figure 2
ROCS image contrast for different scatterers. (A) Given here is an image of a d = 1.06-μm PS bead, T = 0.1 ms integration time of the camera. (B) Given here is a d = 150-nm glass (SiO2) bead, T = 10 ms integration time. (C) Overlay image at T = 100 ms integration time of the camera of a single microtubule is given at two different time points after background subtraction. The microtubule is attached to two optically trapped d = 532-nm PS beads in a dumbbell configuration. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions

4. Figure 3
Viscoelastic properties of single microtubules. (A) Given here is the frequency dependence of the elastic modulus G′ and viscous modulus G″ of a single microtubule obtained by active microrheology. (B) Given here is the theoretical frequency dependence of the elastic modulus G′ and viscous modulus G″ of a single microtubule as a function of different bending modes. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions

5. Figure 4
Stiffness increase for longer microtubules. (A) Shown here is an increase in persistence length according to models and experiments: short MTs are comparably soft and become more rigid for L > 10 μm. (B) Given here is the degree of stiffening on short timescales: the free fit exponent p(L) of the power-law G′(ω) ≈ G′(0) + Aωp slowly drops for long MTs. The black fit line includes all data points in the fit; the red fit line excludes the point at L = 6.5 μm (marked in red parentheses), which we believe to be an outlier. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
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6. Figure 5
Assembly of microtubule networks with defined topology by successively adding microtubule filaments and trapped anchor beads (marked by red outlined circles). (A) Two MTs and three beads are connected to an L-shaped geometry. (B) Three MTs and four beads are connected to a T-shaped geometry. (C) Four MTs and five beads are connected to a cross-shaped geometry. All images were recorded with ROCS microscopy several microns away from the coverslip. Scale bars, 5 μm. To see this figure in color, go online.
Biophysical Journal  , DOI: ( /j.bpj )
Copyright © 2017 Biophysical Society Terms and Conditions