Light-Driven Hydrogel Microactuators for On-Chip Cell Manipulations

Koike, Yuha; Yokoyama, Yoshihiko; Hayakawa, Takeshi

doi:10.3389/fmech.2020.00002

“…Advances in microfabrication have allowed for integration of actuators into "on-chip" devices, including a recent example of a thermoresponsive actuator capable of single-cell mechanical manipulation, placing programmable hydrogel actuators on the forefront of biological research techniques. [124] Actuatable MAMs are able to profoundly influence biology, particularly in cell types that are known to exist in mechanically active environments, such as cardiac, musculoskeletal, and orthopedic tissues. Magnetically responsive MAMs have been used to mechanically stimulate stem cells, directing their maturation toward the osteoblastic lineage.…”

Section: Mams Toward the Study Of Cell Biologymentioning

confidence: 99%

Programmable Mechanically Active Hydrogel‐Based Materials

Dong

¹

,

Ramey-Ward

²

,

Salaita

³

2021

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Hydrogel-based MAMs are the most diverse and intensely studied, and have potential to be programmed with various responding behaviors and have broad applications in areas ranging from biomedical engineering to robotics. Hydrogel programmability, in some literature, refers to the fine-tuning of hydrogel deformation patterns. [4] Other works define programmability of hydrogels as molecular sequencing or arrangement within gel networks. [5] To provide a more consistent overview of programmable hydrogelbased MAMs, this review defines programmability as the ability to tune the input-output response function of the MAMs through either molecular design or patterning of the material across multiple length scales. There are MAMs that are responsive but the response function cannot be easily altered or tuned. For example, a conventional hydrogel can swell and deswell by controlling the humidity. But without spatially patterning the material or without doping certain copolymers into the gel, this type of conventional material is not inherently programmable. We will further discuss the approaches to integrate programmability into MAMs in Section 3.In this review, we first describe the chemical components of hydrogel-based MAMs and their fabrication, followed by specific approaches toward programmability. Then, a detailed classification of responsivity mechanisms is provided, along with discussion of the intimate relationships between material structure and their responsive behaviors. We then end by summarizing current applications of MAMs across multiple disciplines, and the future directions and applications of mechanically responsive hydrogels. Components of HydrogelsMechanical responsivity has been observed in nearly all types of materials both hard and soft materials, spanning from metals to ceramics and polymers. Popular examples include shape-memory metal alloys, [6] piezoelectric ceramics, [7] and thermoresponsive polymers. [8] Herein, we will exlusively discuss programmable MAMs that are primarily composed of polymer hydrogels. This is because hydrogel materials are great candidates for flexible devices and bioengineering studies, and this has inspired multidisciplinary research and numerous potential applications. To be more consistent, inorganic nanoparticles, plastic, rubber, ceramics, polymer micelles/capsules, will not be discussed here since these types of materials are not hydrogels. Programmable mechanically active materials (MAMs) are defined as materials that can sense and transduce external stimuli into mechanical outputs or conversely that can detect mechanical stimuli and respond through an optical change or other change in the appearance of the material. Programmable MAMs are a subset of responsive materials and offer potential in next generation robotics and smart systems. This review specifically focuses on hydrogel-based MAMs because of their mechanical compliance, programmability, biocompatibility, and cost-efficiency. First, the composition of hydrogel MAMs along with the top-down and bottom-up a...

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“…Microfabrication processes were used to fabricate the on-chip gel actuators and light absorbers. The detailed fabrication process is explained in [18]. To pattern the PNIPAAm, we used photo-processable PNIPAAm (Bioresist R , Nissan Chemical Corporation, Tokyo, Japan).…”

Section: Fabricationmentioning

confidence: 99%

“…1 (a). In our previous work [18,19], we succeeded in integrating a large number of gel actuators into a microfluidic chip and driving multiple actuators by irradiating the integrated gel actuators with patterned light. Additionally, we used the integrated gel actuators to demonstrate various cell manipulations, including cell transporting, trapping and sorting.…”

Section: Introductionmentioning

confidence: 99%

Real-time irradiation system using patterned light to actuate light-driven on-chip gel actuators

Koike

¹

,

Kodera

²

,

Yokoyama

³

et al. 2021

Preprint

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0

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A light-driven gel actuator is a potential candidate for a single-cell manipulation tool because it allows cells to be manipulated while ensuring less damage. Moreover, a large number of actuators can be integrated into a microfluidic chip because no wiring is required. Previously, we proposed a method for cell manipulation using light-driven gel actuators. However, the system used in the previous work did not allow the targeted cells to be manipulated in real time because the system used in the previous work could only irradiate preprogrammed patterned light. Moreover, when a large number of gel actuators are integrated into a chip, the Gaussian distribution of the laser light source results in the response characteristics of the gel actuators varying with the location of the actuator. In this work, we constructed a system that homogenized the intensity of the patterned light used for irradiation, allowing multiple gel actuators to be driven in parallel in real time. The intensity-homogenized patterned light improved the variations in the response characteristics of the gel actuators, and as a result, we succeeded in actuating gel actuators with various light patterns in real time.

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“…However, contact methods incur the risk of cell damage when the microstructures contact the target cells. To overcome these problems, on-chip gel actuators that have a similar softness to cells are attracting considerable attention [13][14][15][16][17][18][19]. Although they use a contact method, on-chip gel actuators cause less physical damage to cells because they are soft.…”

Section: Introductionmentioning

confidence: 99%

Real-time irradiation system using patterned light to actuate light-driven on-chip gel actuators

Koike

¹

,

Kodera

²

,

Yokoyama

³

et al. 2022

Robomech J

Self Cite

1

0

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A light-driven gel actuator is a potential candidate for a single-cell manipulation tool because it allows cells to be manipulated while ensuring less damage. Moreover, a large number of actuators can be integrated into a microfluidic chip because no wiring is required. Previously, we proposed a method for cell manipulation using light-driven gel actuators. However, the system used in the previous work did not allow the targeted cells to be manipulated in real time because the system used in the previous work could only irradiate preprogrammed patterned light. Moreover, when a large number of gel actuators are integrated into a chip, the Gaussian distribution of the laser light source results in the response characteristics of the gel actuators varying with the location of the actuator. In this work, we constructed a system that homogenized the intensity of the patterned light used for irradiation, allowing multiple gel actuators to be driven in parallel in real time. The intensity-homogenized patterned light improved the variations in the response characteristics of the gel actuators, and as a result, we succeeded in actuating gel actuators with various light patterns in real time.

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Light-Driven Hydrogel Microactuators for On-Chip Cell Manipulations

Cited by 15 publications

References 36 publications

Programmable Mechanically Active Hydrogel‐Based Materials

Programmable Mechanically Active Hydrogel‐Based Materials

Real-time irradiation system using patterned light to actuate light-driven on-chip gel actuators

Real-time irradiation system using patterned light to actuate light-driven on-chip gel actuators

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