Optical stretching as a tool to investigate the mechanical properties of lipid bilayers

Solmaz, Mehmet; Sankhagowit, Shalene; Biswas, Roshni; Mejía, Camilo A.; Povinelli, Michelle L.; Malmstadt, Noah

doi:10.1039/c3ra42510j

Cited by 25 publications

(32 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The setup uses the diverging beams from two optical fibers to trap and stretch a GUV in a microfluidic channel. We have used the DBOT to measure GUVs with different lipid compositions [2]. We found that gel-phase membranes are significantly stiffer than liquid-phase membranes, consistent with previous reports.…”

Section: Measurements Of Mechanical Properties Of Cell Membranes In Asupporting

confidence: 82%

Optical Trapping, Stretching, and Self-Assembly for Biological Measurements

Biswas

Jaquay

Solmaz

et al. 2014

Frontiers in Optics 2014

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Measurements Of Mechanical Properties Of Cell Membranes In Asupporting

confidence: 82%

Optical Trapping, Stretching, and Self-Assembly for Biological Measurements

Biswas

Jaquay

Solmaz

et al. 2014

Frontiers in Optics 2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…As in our previous work measuring steady-state elastic deformation of lipid bilayers, 18,19 GUVs in an aqueous solution were flowed through a square glass capillary tube to a position between two laser diode-coupled optical fibers, where each vesicle was trapped and stretched via optical forces. Fig.…”

Section: Resultsmentioning

confidence: 99%

“…18,19 This experiment covered the same range of applied laser powers as used in the previously described step power experiment. In the regime where bilayer deformation is dominated by bending modes, there is a log-linear relationship between applied tension and area strain.…”

Section: Resultsmentioning

confidence: 99%

Viscoelastic deformation of lipid bilayer vesicles

Sankhagowit

Biswas

et al. 2015

Soft Matter

Self Cite

View full text Add to dashboard Cite

Lipid bilayers form the boundaries of the cell and its organelles. Many physiological processes, such as cell movement and division, involve bending and folding of the bilayer at high curvatures. Currently, bending of the bilayer is treated as an elastic deformation, such that its stress-strain response is independent of the rate at which bending strain is applied. We present here the first direct measurement of viscoelastic response in a lipid bilayer vesicle. We used a dual-beam optical trap (DBOT) to stretch 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) giant unilamellar vesicles (GUVs). Upon application of a step optical force, the vesicle membrane deforms in two regimes: a fast, instantaneous area increase, followed by a much slower stretching to an eventual plateau deformation. From measurements of dozens of GUVs, the average time constant of the slower stretching response was 0.225 ± 0.033 s (standard deviation, SD). Increasing the fluid viscosity did not affect the observed time constant. We performed a set of experiments to rule out heating by laser absorption as a cause of the transient behavior. Thus, we demonstrate here that the bending deformation of lipid bilayer membranes should be treated as viscoelastic.

show abstract

“…10,11 However, in general, thermodynamic and mechanical characterization requires separate experimental setups which constitute a serious limit for a high throughput analysis. Previous studies [22][23][24] on the deformation of vesicles in an OS were conducted with low power 808 nm laser diodes, in which heating effects were not considered. Such temperature effects have been characterized in optical tweezers 12 and in dual-beam laser traps 13 for a specific, commonly used wavelength (1064 nm).…”

Section: Introductionmentioning

confidence: 99%

Deformation of phospholipid vesicles in an optical stretcher

et al. 2015

View full text Add to dashboard Cite

Phospholipid vesicles are common model systems for cell membranes. Important aspects of the membrane function relate to its mechanical properties. Here we have investigated the deformation behaviour of phospholipid vesicles in a dual-beam laser trap, also called an optical stretcher. This study explicitly makes use of the inherent heating present in such traps to investigate the dependence of vesicle deformation on temperature. By using lasers with different wavelengths, optically induced mechanical stresses and temperature increase can be tuned fairly independently with a single setup. The phase transition temperature of vesicles can be clearly identified by an increase in deformation. In the case of no heating effects, a minimal model for drop deformation in an optical stretcher and a more specific model for vesicle deformation that takes explicitly into account the angular dependence of the optical stress are presented to account for the experimental results. Elastic constants are extracted from the fitting procedures, which agree with literature data. This study demonstrates the utility of optical stretching, which is easily combined with microfluidic delivery, for the future serial, high-throughput study of the mechanical and thermodynamic properties of phospholipid vesicles.

show abstract

Optical stretching as a tool to investigate the mechanical properties of lipid bilayers

Cited by 25 publications

References 50 publications

Optical Trapping, Stretching, and Self-Assembly for Biological Measurements

Optical Trapping, Stretching, and Self-Assembly for Biological Measurements

Viscoelastic deformation of lipid bilayer vesicles

Deformation of phospholipid vesicles in an optical stretcher

Contact Info

Product

Resources

About