Optical Tweezers System with Video-Based Force Detection

Trap and manipulate molecules, particles, or cells and measure their forces with sub-pN resolution.


Overview

•    Single or dual beam optical tweezers system based on an inverted microscope
•    3D real-time video-based force measurements with sub-pN resolution
•    Huge free space above optical trap for all kinds of sample chambers and carriers
•    Manipulate and navigate trapped objects with nanometer precision
•    Easily extendable to fluorescence, STED, Raman spectroscopy, TIRF, or CLS
•    Compact and ultrastable modular design
•    No detector adjustments required
•    Fast, easy, and reliable force calibration
•    Customizable LabViewTM interface
•    New: Combinable with time-resolved confocal microscopy


Applications

There is a wide field of applications that includes the investigation of single molecules and motor proteins, receptor-ligand-interactions, intramolecular elasticity, protein folding and unfolding, and controlled nanopore translocations. Scrutinize polymer elasticity or DNA overstretching phenomena in detail. Trap individual particles inside living cells or analyze interactions on artificial or natural membranes like cell surfaces. Last, but not least measuring Brownian motion of microscopic particles in various environments, tracking of particles, and rheological surveys (e.g. inside of microfluidic devices) are some of many further applications.


Huge Work Space

The PicoTweezers system is a high-performance video-based single or dual trap force spectroscopy instrument with decisive advantages over common optical tweezers systems with quadrant photodiode based position detection. In the PicoTweezers system the entire force detection and the laser beam control is located underneath the trapping lens and inside the upper deck of a two-deck Olympus microscope platform forming an extremely compact and robust instrument.

Due to the absence of a classical force detection module with a condenser lens confocally arranged to the trapping lens, PicoTweezers with its open space architecture provides an unrivalled free space above the optical trap. This open work space allows you to choose from a wide range of standard sample carriers, from Petri dishes, microscope slides and standard microtiter plates to microfluidic sample cartridges without size or height constraints.

The space around the optical trap is covered by a sturdy microscope housing serving as Faraday shielding, and is equipped with laser safety components, an IR-blocking observation window and side ports for easy sample chamber access.


Robustness by Design

Due to the absence of a force detection module above the optical trap, which is always prone to misalignments and the introduction of vibrations into experiments, the PicoTweezers system is a highly robust and sensitive instrument that requires only a single optical alignment procedure once at installation.


Modular Setup

The PicoTweezers system is a modular system you may compose individually according to your needs and experimental requirements, or use these modules as upgrades for existing optical tweezers or microscope systems.

Here, we provide a list of all modules with their respective specifications:

Microscope Platform

Microscope Module

Olympus IX73 Two-Deck Microscope Platform with Tilting Binocular Tube, IR-Safety Filtering and Camera Adapter

Lower Deck: Free for various modules: Can easily be equipped with Fluorescence, STED, CLS, or Raman

Upper Deck: Ionovation PicoTweezers Deck: Accommodates Trapping and Force Detection Modules

 
60x U Plan S Apo
Water Immersion Objective

Working distance: 0.28 mm; NA 1.2; Cover slide correction: 0.13 – 0.21 mm

 

IR-Safety Microscope Housing with Controllable Illumination

Housing with laser safety shutter and IR-blocking observation window

Side ports for easy sample carrier access during experimentation
Faraday shielding

 

Overview Color Camera System

2056 x 1542 pixel resolution, 57 Hz

IR-safety filtering

 

Data Station and Electronics

System specific, LabView pre-configured Windows PC with Monitor, Keyboard, Mouse

PicoTweezers software suite with programmable LabView™ interface

Full software control of illumination, Laser intensity, trapping, nano- and micropositioning

Lateral and axial force and position real-time measurement and recording; scriptable
Automated laser safety control

Objective Upgrade

Customized IR-Enhanced 60x U Plan S Apo Water Immersion Objective

50% increased transmission at 1064 nm compared to standard 60x U Plan S Apo objective

50% increased maximum trapping force and trap stiffness

Microscope Module 2

Customized Module Based on Zeiss, Nikon, or Leica Microscope Platform
Specifications According to Requirement

Optical Trapping

Trapping Module 1

 
Required Module
for Single Trap

1 W 1064 nm Unpolarized TEM00 cw Fiber Laser with M2 < 1.2

Pigtail Single Mode Fiber Interface and Beam Expander

Stabilized power supply and controller with output power fluctuations < 1%

Dicroic beam coupling into optical path of microscope

Laser output power controllable between 1 and 100% in 1% steps

 

Generation of a single, stationary optical trap

Trap can be switched on and off both via software or manually

Maximum trapping force up to 300 pN with trap stiffness up to 0.35 pN/nm for 2 µm polystyrene bead in water

Position drift of trap < 0.4 nm in 2 minutes

Laser Upgrade 2 W

 

Upgrade for
Single Trap

2 W 1064 nm Unpolarized TEM00 cw Fiber Laser with M2 < 1.2

 

Allows maximum trapping force up to 600 pN with trap stiffness up to 0.7 pN/nm for 2 µm polystyrene bead in water

Laser Upgrade 10 W

 

Upgrade for
Single Trap

10 W 1064 nm Linearly Polarized TEM00 cw Solid-State Laser with M2 < 1.4

Adapted Beam Expander

Stabilized power supply and controller with output power fluctuations < 0.2%

 

Allows maximum trapping force up to 3000 pN with trap stiffness up to 3.5 pN/nm for 2 µm polystyrene bead in water

Position drift of trap < 0.6 nm in 2 minutes

Trapping Module 2

 
Required Module
for Dual Trap

2 W 1064 nm Linearly Polarized TEM00 cw Fiber Laser with M2 < 1.2

Pigtail Single Mode Fiber Interface and Beam Expander

Stabilized power supply and controller with output power fluctuations < 1%

Dicroic beam coupling into optical path of microscope

Laser output power controllable between 1 and 100% in 1% steps

 

Generation of one stationary optical trap and a second, moveable optical trap

Both traps can be independently switched on and off, both via software or manually

Laser intensity distribution for both traps, from 0:100 to 100:0 in 1% steps

At 50:50 power distribution: Maximum trapping force up to 300 pN with trap stiffness up to 0.35 pN/nm
    for each 2 µm polystyrene bead in water; Full power to one trap: up to 600 pN maximum trapping force

Position drift of stationary trap < 0.4 nm in 2 minutes

Second trap fully moveable and controllable in a lateral range (XY) of 60 x 60 µm
    and an axial range (Z) of 10 µm, centered around the stationary trap

Absolute lateral position resolution at 100 Hz with closed-loop position control of second trap is 1.8 nm;
    absolute axial position resolution is 0.4 nm

Position drift of second trap is < 0.6 nm in 2 minutes

Laser Upgrade 10 W

 

Upgrade for
Dual Trap

10 W 1064 nm Linearly Polarized TEM00 cw Solid-State Laser with M2 < 1.4

Adapted Beam Expander

Stabilized power supply and controller with output power fluctuations < 0.2%

 

At 50:50 power distribution: Maximum trapping force up to 1500 pN with trap stiffness up to 3.5 pN/nm for
each 2 µm polystyrene bead in water;
Full power to one trap: up to 3000 pN maximum trapping force

Position drift of stationary trap < 0.6 nm in 2 minutes

Position drift of moveable trap < 0.9 nm in 2 minutes

Nano- and Micropositioning

Nanopositioning Module

 

Optional Module, Recommended for Force Measurements

Piezo-Controlled High Precision XYZ-Stage

Lateral range of 100 x 100 µm with closed-loop position control and resolution of 1 nm

Axial range of 20 µm with closed-loop position control and resolution of 0.1 nm

Open-loop travel of 130 x 130 x 25 µm

Capacitive sensor elements

Digital multi channel piezo controller with USB and Ethernet connection

 

Adapter board for sample carrier mounting

Nanopositioning Upgrade 1

 

Upgrade for Increased Movement Range

Piezo-Controlled High Precision XYZ-Stage

Lateral range of 200 x 200 µm with closed-loop position control and resolution of 2 nm

Open-loop travel of 250 x 250 x 25 µm

Nanopositioning Upgrade 2

 

Upgrade for Increased Movement Range

Piezo-Controlled High Precision XYZ-Stage

Lateral and axial range of 300 x 300 x 300 µm with closed-loop position control and resolution of 2 nm

Open-loop travel of 340 x 340 x 340 µm

Customized Nanopositioning Module

Specifications According to Requirement

Piezo Controlled Micropositioning Module

 

Optional Module, Stand-alone, or Complement for Nanopositioning

Ultrasonic Piezomotor-Controlled Precision XY-Stage

Movement range of 25 x 25 mm

Incremental movement of 0.3 µm

Sensor resolution of 0.1 µm

Self-locking and no heat generation when resting

Silent piezomotor drive

Digital ultrasonic piezomotor controller with USB and Ethernet connection

Customized Micropositioning Module

Specifications According to Requirement

3D-Force Measurement

Force Measurement Module

 

Optional Module, Recommends Nano- or Micropositioning Module

Video-Based Particle Detection for Reliable 3D-Force Measurements

Open space architecture: No detection module on top of trapping objective required anymore!

Free space of at least 212 mm width, 264 mm depth and 75 mm height above optical trap

No spatial restriction for sample carriers

Compatible with Petri dishes, microscope slides and standard Microtiter plates

400 Hz real-time force detection camera module

Force detection via particle tracking in stationary optical trap

No detector alignment or readjustment required

Easy force calibration routine

Scriptable measurement procedures

Excellent long-term stability, force drift < 0.7 pN in 2 minutes when trap stiffness is 0.35 pN/nm or less

0.4 pN force resolution at 400 Hz and 0.1 pN force resolution at 25 Hz when trap stiffness is 0.35 pN/nm or less

Illumination for force detection in wavelength band between 820 and 880 nm

No crosstalk between force detection and fluorescence, STED, CLS, or Raman

Beam Shaper

 

Upgrade for Force Measurement Module

Engageable Beam Shaper for Improved Force Measurements on Reflective Optical Interfaces

Shapes laser beam profile to suppress backreflected and backscattered light

Allows interference-free axial force measurements in proximity of weakly reflective interfaces

Increases axial trapping stiffness by 40 %

Publications

A. Sischka, L. Galla, A.J. Meyer, A. Spiering, S. Knust, M. Mayer, A.R. Hall, A. Beyer, P. Reimann, A. Gölzhäuser, and D. Anselmetti: Controlled Translocation of DNA Through Nanopores in Carbon Nano-, Silicon-Nitride- and Lipid-Coated Membranes. Analyst, 140, 4843 (2015)

T. Jany, A. Moreth, C. Gruschka, A. Sischka, A. Spiering, M. Dieding, Y. Wang, S. Haji Samo, A. Stammler, H. Boegge, G. Fischer von Mollard, D. Anselmetti, and T. Glaser: Rational Design of a Cytotoxic Dinuclear Cu-2 Complex That Binds by Molecular Recognition at Two Neighboring Phosphates of the DNA Backbone. Inorganic Chemistry, 54, 2679 (2015)

L. Galla, A.J. Meyer, A. Spiering, A. Sischka, M. Mayer, A.R. Hall, P. Reimann, and D. Anselmetti: Hydrodynamic Slip on DNA Observed by Optical Tweezers-Controlled Translocation Experiments with Solid-State and Lipid-Coated Nanopores. Nano Letters, 14, 4176 (2014)

S. Knust, A. Spiering, H. Vieker, A. Beyer, A. Gölzhäuser, K. Tönsing, A. Sischka, and D. Anselmetti: Video-Based and Interference-Free Axial Force Detection and Analysis for Optical Tweezers. Review of Scientific Instruments, 83, 103704 (2012)