IRONSperm: Sperm-templated soft magnetic microrobots

Abstract

<jats:p>We develop biohybrid magnetic microrobots by electrostatic self-assembly of nonmotile sperm cells and magnetic nanoparticles. Incorporating a biological entity into microrobots entails many functional advantages beyond shape templating, such as the facile uptake of chemotherapeutic agents to achieve targeted drug delivery. We present a single-step electrostatic self-assembly technique to fabricate IRONSperms, soft magnetic microswimmers that emulate the motion of motile sperm cells. Our experiments and theoretical predictions show that the swimming speed of IRONSperms exceeds 0.2 body length/s (6.8 ± 4.1 µm/s) at an actuation frequency of 8 Hz and precision angle of 45°. We demonstrate that the nanoparticle coating increases the acoustic impedance of the sperm cells and enables localization of clusters of IRONSperm using ultrasound feedback. We also confirm the biocompatibility and drug loading ability of these microrobots, and their promise as biocompatible, controllable, and detectable biohybrid tools for in vivo targeted therapy.</jats:p>

Medical Micro/Nanorobots in Precision Medicine

“…Motile sperm loaded with doxorubicin were integrated into a 3D-printed magnetic tubular microstructure that permitted magnetic guidance and assistance to push against the tumor site. [129] The use of electrostatic self-assembly was used to fabricate biohybrid sperms [187] and Chlamydomonas reinhardtii based microrobots carrying magnetic nanoparticles and therapeutic loads. [188] In another example, Escherichia coli (E. coli) was captured with drug-loaded polyelectrolyte multilayer microparticles containing magnetic nanoparticles, and doxorubicin.…”

Starfish-inspired Ultrasound Ciliary Bands for Microrobotic Systems

“…Microrobots could facilitate specialized tasks in medicine 17 , including surgical procedures and drug delivery to hard-to-access sites in vivo. Chemical [18][19][20][21][22][23][24][25][26] and external field-driven, such as magnetic [27][28][29][30][31][32][33][34][35] , light [36][37][38] , electrical 39 , biohybrid [40][41][42] or ultrasound [43][44][45][46][47][48] -microrobots are attractive because they do not require an onboard power supply or intricate moving parts and allow wireless control of the microrobot. Nonlinear ultrasound provides an alternate and attractive method to generate propulsion in vivo.…”

Melt Electrospinning Writing of Magnetic Microrobots

“…Most of them were synthesized with high yields and low‐cost facilities by self‐assembly and electroplating approach. [ 11b, 12b ] Sperm‐templated method, [ 13 ] magnetron sputter deposition, [ 14 ] and self‐scrolling method [ 15 ] were commonly used approaches for the magnetic motors fabrication. Recently, the tendency of new generation motor requires specific architecture design to achieve desired functions.…”