Fig. 1. An overview of cell manipulation and neuromodulation using tapered optical fibers. (a) Single-cell trapping and analysis;(b) multi-cellular assembly; (c) sub-cellular manipulation; (d) neuromodulation

Fig. 2. Optical trapping principle of tapered optical fiber tweezers (TOFTs)^[31-32]。(a) Schematic of optical trapping and manipulation using TOFTs^[31]; (b) light intensity distribution near the fiber tip^[32]; (c)-(d) calculated optical force exerted on particles by TOFTs^[31]: (c) variation of optical force in axial direction (F_x) with D_A; (d) transverse optical force (F_y) distribution at D_A=4.5 μm

Fig. 3. Trapping particles, cells, and bacterium by TOFTs. (a) TOFTs for trapping particles and cells of different sizes: (a1) silica microspheres with a diameter of 0.7 μm^[31]; (a2) E.coli^[31]; (a3) yeast cells^[34]; (a4) Chinese hamster ovary cell^[35]; (b) non-contact optical trapping of E.coli by TOFTs^[36]

Fig. 4. Flexible manipulation of trapped particles and bacteria by TOFTs. (a) Arrangement of six particles into a hexagon^[31]: the particles are picked up and placed into the designated position after trapping by flexible movement of the fiber (yellow arrow indicated); (b)-(c) flexible manipulation of a trapped E.coli bacterium in flowing environment^[37], where the yellow solid arrows indicate the fiber movement direction and the blue arrows indicate the flowing direction

Fig. 5. TOFTs for single-cell labeling and analysis^[39]. (a)-(b) Schematic and experimental images of bacterial trapping and labeling;(c) real-time reflected optical signal from labeled single bacteria with different sizes

Fig. 6. Dynamic analysis of motile bacteria via non-contact optical trapping of single bacterium^[36]. (a) Optical microscopy images showing capture and struggle of E.coli; (b) schematic of the bacterium dynamics in the non-contact trapping

Fig. 7. Realizing multicellular assembly by TOFTs^[44]. (a) Schematic of optical assembly of particles and cells via TOFTs; (b) microscopic images of one-dimensional (1D) patterned particle chains; (c) microscopic images of two-dimensional (2D) particle arrays; (d) microscopic images of yeast cell chains

Fig. 8. Biological optical waveguides (bio-WGs) and bio-nanospear assembly. (a) Bio-WGs assembly via extended optical gradient force^[45]: (a1) schematic of optical assembly and bio-WGs formation; (a2) distribution of energy density of TOFTs capturing different numbers of E. coli; (a3) images of formed bio-WGs with different lengths; (b) bio-nanospear assembly via extended optical gradient force^[46]: (b1) schematic illustration of assembled bio-nanospear; (b2) optical image of bio-nanospear assembled from a yeast and L. acidophilus cells

Fig. 9. Muli-cell collection and sorting by TOFTs^[48]. (a) Schematic showing different light response behaviors of E. coli and red blood cells (RBCs) in tapered fiber tip; (b) selective capture: (b1) E. coli and RBCs are mixed together in channel 1 when the laser is turned off; (b2)-(b4) E. coli is attracted and the RBCs are released when the laser is turned on

Fig. 10. Principle of single-cell microsurgery and repair^[50]. (a) Schematic of thermoplasmonics-based membrane perforation and repair; (b) single-cell microsurgery (b1, b2) and repair (b3, b4) via TOFTs; (c) optical extraction and manipulation of microfilaments from the micropore in cell membrane; (d) TOFTs trap and release a mitochondria-like organelle, and the trapped organelle is released as the laser is turned off

Fig. 11. TOFTs manipulating chloroplast^[51]. (a) Schematic of TOFTs for chloroplast chain assembly in plant cells; (b) formation process of chloroplast chains; (c) TOFTs for two-dimensional assembly of chloroplasts

Fig. 12. Neuron guidance of TOFTs^[35,52]. (a) Illustration of the neuronal beacon for repulsive axonal guidance^[52]; (b) laser assisted navigation of RCNs^[52]; (c) modulation of neuronal growth cones using TOFTs^[35]; (d) nanosurgery on neuronal protrusions using TOFTs-based “laser scissors”^[35]

Fig. 13. TFOE for high-precision optoacoustic stimulation^[57]. (a) Schematic of TFOE enabling single-neuron stimulation; (b) manufacturing steps of TFOE: multiwall CNT/PDMS mixture as coating material was casted on a metal mesh followed by a punch-through method to coat the tapered fiber; (c) fluorescence images and calcium traces stimulated by TFOE with a laser duration of 50 ms and 1 ms