Dynamical hologram generation for high speed optical trapping of smart droplet microtools

Optically-controlled platforms for transfection and single- and sub-cellular surgery

Improving the resolution of biological research to the single-cell or sub-cellular level is of critical importance in a wide variety of processes and disease conditions. Most obvious are those linked to aging and cancer, many of which are dependent upon stochastic processes where individual, unpredictable failures or mutations in individual cells can lead to serious downstream conditions across the whole organism. The traditional tools of biochemistry struggle to observe such processes: the vast majority are based upon ensemble approaches analysing the properties of bulk populations, which means that details of individual constituents is lost. What are required, then, are tools with the precision and resolution to probe and dissect cells at the single-micron scale: the scale of the individual organelles and structures that control their function. In this review, we highlight the use of highly-focused laser beams to create systems which provide precise control and specificity at the single-cell or even single-micron level. The intense focal points generated can directly interact with cells and cell membranes, which in conjunction with related modalities such as optical trapping provide a broad platform for the development of single-cell and sub-cellular surgery approaches. These highly tuneable tools have been demonstrated to deliver or remove material from cells of interest, and they can simultaneously excite fluorescent probes for imaging purposes or plasmonic structures for very local heating. We discuss both the history and recent applications of the field, highlighting the key findings and developments over the last 40 years of biophotonics research.

The grab-and-drop protocol: a novel strategy for membrane protein isolation and reconstitution from single cells

Samples of cell membrane were non-destructively removed from individual, live cells using optically trapped beads, and deposited into a supported lipid bilayer mounted on an S-layer protein-coated substrate.

Mode division multiplexing technology for single-fiber optical trapping axial-position adjustment

We demonstrate trapped yeast cell axial-position adjustment without moving the optical fiber in a single-fiber optical trapping system. The dynamic axial-position adjustment is realized by controlling the power ratio of the fundamental mode beam (LP01) and the low-order mode beam (LP11) generated in a normal single-core fiber. In order to separate the trapping positions produced by the two mode beams, we fabricate a special fiber tapered tip with a selective two-step method. A yeast cell of 6 μm diameter is moved along the optical axis direction for a distance of ~3 μm. To the best of our knowledge, this is the first demonstration of the trapping position adjustment without moving the fiber for single-fiber optical tweezers. The excitation and utilization of multimode beams in a single fiber constitutes a new development for single-fiber optical trapping and makes possible more practical applications in biomedical research fields.