Controllable Patterning of Different Cells Via Optical Assembly of 1D Periodic Cell Structures

Abstract

Flexible patterning of different cells into designated locations with direct cell–cell contact at single‐cell patterning precision and control is of great importance, however challenging, for cell patterning. Here, an optical assembly method for patterning of different types of cells via direct cell–cell contact at single‐cell patterning precision and control is demonstrated. Using Escherichia coli and Chlorella cells as examples, different cells are flexibly patterned into 1D periodic cell structures (PCSs) with controllable configurations and lengths, by periodically connecting one type of cells with another by optical force. The patterned PCSs can be flexibly moved and show good light propagation ability. The propagating light signals can be detected in real‐time, providing new opportunities for the detection of transduction signals among patterned cells. This patterning method is also applicable for cells of other kinds, including mammalian/human cells.

Single Upconversion Nanoparticle–Bacterium Cotrapping for Single‐Bacterium Labeling and Analysis

“…One main concern about this optical strategy for single‐bacterium labeling and analysis is photodamage to the trapped bacteria by the laser beam. Fortunately, we have previously shown that the cell viability was not affected by the trapping laser at an even larger optical power of ≈30 mW, with other conditions similar; in fact, even cell growth and division can be directly observed after trapping . Therefore, photodamage induced by the laser beam with an optical power less than 30 mW can be ignored for single‐bacterium labeling and sizing using our method.…”

All-optical targeted drug delivery and real-time detection of a single cancer cell

“…A TFP (see methods for fabrication) sheathed partly by a glass capillary was inserted into the cell medium using a tunable six‐axis micromanipulator (Kohzu Precision Co., Ltd., resolution: 50 nm). A 980‐nm laser beam (Beijing wavicle laser Co., Ltd., Beijing, China) with an optical power of 20 mW, which exhibits relatively low absorption for biological specimens [28], was launched into the TFP to create a stable optical trap. By precisely moving the TFP to approach the drug carriers [mesoporous silica microparticles loaded with an anticancer drug – doxorubicin (MMD)] sequentially, one or several drug carriers can be trapped near the tip of the TFP by the optical gradient force.…”

“…But, accordingly, a higher photothermal effect can also be generated, which can lead to the instability of liquid environment and is also harmful to biological specimens. In our experiment, to avoid an obvious photothermic effect, the laser power is generally set as less than 40 mW [28]. When the delivery process was completed, the trapped MMD can be released by turning off the laser source.…”

Trapping and Detection of Nanoparticles and Cells Using a Parallel Photonic Nanojet Array

“…Both the trapping light and detection signals propagate through the fiber probe, making the device highly autonomous and free of bulky optical elements. The flexibility and small size of this device allow it to operate in narrow spaces such as blood vessels, in vivo , biocapillaries, or lab-on-a-chip devices. − To experimentally verify the trapping and detection ability of the photonic nanojet array, fluorescent PS nanoparticles with an average diameter of 190 nm (Figure d), which can be considered as rough approximate models for viruses and small spherical bacteria, were used. When excited by a 398 nm laser, the emission of the fluorescent PS nanoparticles at 518 nm was observed with an optical microscope (Figure e).…”