. 2022 Jun 24;15(13):4442. doi: 10.3390/ma15134442

Table 1.

Nanoswimmers classified by their type, composition, mechanism and foreseen applications.

Swimmer Type	Composition	Mechanism	Application
Non-Hybrid Swimmers
Multilayer magnetic/catalytic swimmer [49]	Co/Pt multilayer on SiO $_{2}$	H $_{2}$ O $_{2}$ catalysis and magnetical steering	Studying swimming behavior
Magnetoresponsive swimmer [50]	CoFe $_{2}$ O $_{4}$ and BaTiO $_{3}$ on SiO $_{2}$	Charge generation via interaction of magnetostrictive and piezoelectric layers	Remote controlling/triggering electrochemical reactions
Catalytic swimmer [53]	Pt on mesoporous SiO $_{2}$	Pt catalyzed H $_{2}$ O $_{2}$ breakdown	Drug delivery
Fuel-free photocatalytic swimmer [54]	Au coated TiO $_{2}$	UV-light driven self-electrophoresis	Illumination controlled propulsion
Photochemically driven swimmer [56]	Cu on TiO $_{2}$	UV light or H $_{2}$ O $_{2}$ fuel depending on solution conditions	Studying swimming and interactions between passive and active colloids
Photochemically driven swimmers [60]	Various metals on TiO $_{2}$	UV light and H $_{2}$ O $_{2}$ fuel	Studying effects of coating material on swimmer propulsion
Two-directional photoresponsive swimmer [61]	Au-capped TiO $_{2}$	Switch in reaction site (Au to TiO $_{2}$ ) based on used light wavelength (UV to green)	Reversible propulsion direction
Nanocube and platelet-coated swimmers [51]	Co $_{3}$ O $_{2}$ nanocubes or platelets on TiO $_{2}$	UV-light-driven photocatalytic/self-electrophoretic propulsion	Studying effects of coating morphology on swimming
Photochemically driven polymer-cored swimmer [62]	AgCl on PMMA	UV-and-visible-light-driven decomposition of AgCl to Ag	Studying ionic self-diffusiophoresis
Photothermal swimmer [52]	Au on SiO $_{2}$	Light-induced thermal gradient between cap and uncoated half	Fuel-free light-controlled propulsion
Magnetothermal swimmer [24]	Permalloy on SiO $_{2}$	Asymmetric heating of particle with AC magnetic field, steering with DC magnetic field	Magnetic steering and propulsion
Multilayered antibacterial swimmer [45]	Ag on Au on Fe on Mg	Mg-based propulsion, magnetic guidance and collection, bacterial adhesion and Ag release	Killing and collecting bacteria in water
Photocatalytic magnetic swimmer [57]	Ni and Au on TiO $_{2}$	UV-driven propulsion, magnetic reclaiming	Herding, aggregating and collecting passive colloidal species in solution
Galvanic exchange swimmers [63,64]	Metal coating on SiO $_{2}$	Galvanic exchange of partial coating with more noble metal in solution induces an electromotive force	Capping synthesis and material exchange, switching of propulsion mechanism
Liquid metal alloy swimmers [65,66,67]	Capped liquid metal core	Self-diffusiophoresis (non-metallic) or self-electrophoresis (metal) depending on cap material	Propulsion in alkaline environments, biocompatible and bactericidal swimmers, microwelding
Hybrid Swimmers
Catalase swimmer [74]	SiO $_{2}$ -capped catalase-modified mesoporous SiO $_{2}$	H $_{2}$ O $_{2}$ breakdown on catalase-coated side	Biocatalytic propulsion, drug delivery
Hollow-cored urease swimmer [75]	Urease-coated mesoporous SiO $_{2}$ with SiO $_{2}$ , Fe or Au capping	Propulsion via urea decomposition, magnetic steering (with Fe cap), cargo space within particle	Controlled enzymatic swimming, delivery of large-particle cargo
Cell-membrane-coated swimmer [78]	Au-capped SiO $_{2}$ with macrophage cell membrane on exposed SiO $_{2}$	Thermophoretic propulsion, cloaking and cell-specific targeting due to cell membrane coating	Immunological cloaking, cancer cell targeting, assisted cell membrane penetration
Capped platelet cells [48]	Urease-capped platelet cells	Urea-fueled propulsion, retained cell functionality	Harnessing of cells as nanoswimmers
E. coli-based swimmer [70]	E. coli attached to metal-capped polystyrene	Random tumble motion of E. coli, magnetic steering (with Fe coatings)	Fuel-free random or directed propulsion, drug delivery
Biosensor swimmer [84]	MoS $_{2}$ or WS $_{2}$ inside polymer shell partially coated with metals and fluorescent affinity peptide	Catalytic propulsion, magnetic steering and collecting, peptide release and light emission upon encountering target endotoxin	On/off-type species-selective biosensor for bacteria detection
DNA-Based Swimmers
Thermophoretic DNA origami swimmers [76,88]	Custom DNA origami structures on Au particles	Propulsion via asymmetric heating during illumination	Platform for thermophoretic swimmers with adjustable behavior
Magnetic swimmers with DNA origami tails [77,89]	DNA origami flagella conjugated to Au-capped magnetic beads	Flagella-mediated propulsion during magnetic rotation of beads	Custom engineering of movement behavior