Fig. 1. Processing, materials and applications of micro/nanoscale robots

Fig. 2. Femtosecond laser machining of rigid microrobots. (a) Femtosecond laser machining SU-8 magnetic rigid micro-spiral robot^[12]; (b) Femtosecond laser processing of three gel microstructure robots^[13]; (c) Femtosecond laser machining hard magnetic microtubule robot^[14]; (d) Femtosecond laser machining of hard semi-open bowl microrobots^[15]

Fig. 3. Femtosecond laser metal-processing microrobot. (a) Preparation diagram of nickel-Phosphorus (Ni-P) alloy microrobot^[19]; (b) femtosecond laser two-photon induced silver ion reduction in AgNO₃ aqueous solution and (i) silver wire, (ii) silver network micro-structure robot^[23]; (c) Reduction of gold ions by femtosecond laser TPA in AuCl₄ aqueous solution^[25]; (d) Fabrication of nanocrystalline platinum and palladium microrobots by multi-photon lithography^[26]

Fig. 4. Femtosecond laser processing of magnetically responsive hydrogel microrobots. (a) Magnetically responsive soft micro-spiral robots^[35]; (b) Magnetic field/pH-driven micro-helical robots^[36]; (c) Magnetic response-driven droplet microrobots^[37]

Fig. 5. Light-responsive hydrogel microrobots processed by femtosecond lasers. (a) Shrinkage and swelling of temperature-responsive hydrogel microrobots^[40]; (b) Light-driven stepper microrobots^[41]; (c) Light-driven joint microrobots^[42]

Fig. 6. Femtosecond laser processing of pH-responsive hydrogel microrobots. (a) pH-responsive hydrogel leaf microrobots^[44]; (b) pH-responsive flytrap biomimetic microrobot^[45]; (c) pH/temperature dual response driven hydrogel microrobot^[46]

Fig. 7. Femtosecond laser processing of humidity-responsive hydrogel microrobots. (a) Humidity-responsive hydrogel three-piece petal array microrobots^[48]; (b) Humidity-responsive six-petal microrobot^[49]

Fig. 8. Application of microrobots in targeted drug delivery. (a) Intraperitoneal drive and imaging tracking of micro-spiral robot^[50]; (b) Magnetic fields drive biodegradable microspiral robots^[51]; (c) Biodegradable thermotherapy microrobots are driven by rotating and alternating magnetic fields for targeted drug delivery^[52]

Fig. 9. Application of microrobots in cell manipulation. (a) Cell transplantation by a porous microsphere robot^[53]; (b) Microrobots to filter individual cells^[54]; (c) Microrobots capture individual cells^[55]

Fig. 10. Application of microrobot in minimally invasive surgery. (a) The magnetic microneedle robot completes single-cell puncture administration^[56] ; (b) The degradation process and induced neuronal differentiation of SH-SY5 Y cell cell loading soft microswimmers under magnetic stimulation^[57]

Fig. 11. Application of microrobots in microfabrication of precision devices. (a) Micromanipulator robots with submicron probe tips; (b) Leaf-shaped micropump robot^[59]; (c) Turbine-like microrotor robots^[60]

Fig. 12. Application of microrobots in detecting micro-objects. (a) Micro-dumbbell robots^[61]; (b) Probe microrobots^[62]