Addressable Acoustic Actuation of 3D Printed Soft Robotic Microsystems

Abstract

A design, manufacturing, and control methodology is presented for the transduction of ultrasound into frequency-selective actuation of multibody hydrogel mechanical systems. The modular design of compliant mechanisms is compatible with direct laser writing and the multiple degrees of freedom actuation scheme does not require incorporation of any specific material such as air bubbles. These features pave the way for the development of active scaffolds and soft robotic microsystems from biomaterials with tailored performance and functionality. Finite element analysis and computational fluid dynamics are used to quantitatively predict the performance of acoustically powered hydrogels immersed in fluid and guide the design process. The outcome is the remotely controlled operation of a repertoire of untethered biomanipulation tools including monolithic compound micromachinery with multiple pumps connected to various functional devices. The potential of the presented technology for minimally invasive diagnosis and targeted therapy is demonstrated by a soft microrobot that can on-demand collect, encapsulate, and process microscopic samples. Microfabricated devices have led to revolutionary changes in our ability to manipulate small volumes of fluid and microscopic samples contained therein. [1] As a result, majority of state-of-the-art in vitro biomedical platforms contain microfluidic components. Operating these devices requires the use of bulky pumps, compressors, or tethered electrical powering units, which significantly increase the overall size and limit the portability. A key technological challenge has been the development of untethered microfluidic systems that are capable of providing such functionality with wireless control for in vivo applications. Ideally, such systems are expected to determine the timing, duration, and dosage of the intervention and allow remote, noninvasive, repeatable, and reliable control of diagnostic or

Investigating Tissue Mechanics in vitro Using Untethered Soft Robotic Microdevices

“…Projection lithography is convenient and versatile yet the design of the mechanisms are limited to extruded shapes. The polymers that we used, on the other hand, have already been adapted to 3D nanoprinting using two-photon polymerization (Hippler et al, 2019(Hippler et al, , 2020Kaynak et al, 2020). Printing mechanisms around the actuators is one interesting avenue.…”

Light‐Powered Microrobots: Challenges and Opportunities for Hard and Soft Responsive Microswimmers

“…However, more recent developments include better candidates, such as microrobots powered by enzymatic reactions [49,50] water conversion reactions, [8,51] and bodily fluids, such as gastric acid or intestinal fluid. [26,52] Thermal, electric, [25,31,53] and acoustic [25,32,54] control are less explored compared with the aforementioned propulsion and control modalities, and they are often coupled with a different actuating force. Interesting examples of thermoresponsive [55] and thermomagnetic [56] microrobots have been reported for surgical applications, and a thermoelectromagnetic microrobot was developed for drug delivery.…”

“…Thermal, electric, [ 25,31,53 ] and acoustic [ 25,32,54 ] control are less explored compared with the aforementioned propulsion and control modalities, and they are often coupled with a different actuating force. Interesting examples of thermoresponsive [ 55 ] and thermomagnetic [ 56 ] microrobots have been reported for surgical applications, and a thermoelectromagnetic microrobot was developed for drug delivery.…”

3D Printing Hydrogel-Based Soft and Biohybrid Actuators: A Mini-Review on Fabrication Techniques, Applications, and Challenges

“…Similar to magnetic actuation, acoustic energy can be utilized to remotely manipulate micro/nano objects in fluid with high precision ( Matouš et al, 2019 ; Guo et al, 2016 ; Ozcelik et al, 2018 ; Ren et al, 2019 ; Tao et al, 2019 ; Fornell et al, 2019 ). Hydrogel structures that are acoustically stimulated at their resonant frequency can manipulate fluids for mixing ( Orbay et al, 2018 ) or generating fluid flow ( Kaynak et al, 2020 ). In addition, ( Son et al, 2020 ) constructed a remotely controlled hybrid gripper with both magnetic and acoustic actuation, where the acoustically responsive hydrogel converted ultrasound energy to heat for temperature-sensitive swelling/de-swelling.…”