1
|
Lee HK, Yang YJ, Koirala GR, Oh S, Kim TI. From lab to wearables: Innovations in multifunctional hydrogel chemistry for next-generation bioelectronic devices. Biomaterials 2024; 310:122632. [PMID: 38824848 DOI: 10.1016/j.biomaterials.2024.122632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/19/2024] [Accepted: 05/23/2024] [Indexed: 06/04/2024]
Abstract
Functional hydrogels have emerged as foundational materials in diagnostics, therapy, and wearable devices, owing to their high stretchability, flexibility, sensing, and outstanding biocompatibility. Their significance stems from their resemblance to biological tissue and their exceptional versatility in electrical, mechanical, and biofunctional engineering, positioning themselves as a bridge between living organisms and electronic systems, paving the way for the development of highly compatible, efficient, and stable interfaces. These multifaceted capability revolutionizes the essence of hydrogel-based wearable devices, distinguishing them from conventional biomedical devices in real-world practical applications. In this comprehensive review, we first discuss the fundamental chemistry of hydrogels, elucidating their distinct properties and functionalities. Subsequently, we examine the applications of these bioelectronics within the human body, unveiling their transformative potential in diagnostics, therapy, and human-machine interfaces (HMI) in real wearable bioelectronics. This exploration serves as a scientific compass for researchers navigating the interdisciplinary landscape of chemistry, materials science, and bioelectronics.
Collapse
Affiliation(s)
- Hin Kiu Lee
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Ye Ji Yang
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Gyan Raj Koirala
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea; Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Suyoun Oh
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Tae-Il Kim
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea; Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon, 16419, Republic of Korea.
| |
Collapse
|
2
|
Plummer A, Adkins C, Louf JF, Košmrlj A, Datta SS. Obstructed swelling and fracture of hydrogels. SOFT MATTER 2024; 20:1425-1437. [PMID: 38252539 DOI: 10.1039/d3sm01470c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Obstructions influence the growth and expansion of bodies in a wide range of settings-but isolating and understanding their impact can be difficult in complex environments. Here, we study obstructed growth/expansion in a model system accessible to experiments, simulations, and theory: hydrogels swelling around fixed cylindrical obstacles with varying geometries. When the obstacles are large and widely-spaced, hydrogels swell around them and remain intact. In contrast, our experiments reveal that when the obstacles are narrow and closely-spaced, hydrogels fracture as they swell. We use finite element simulations to map the magnitude and spatial distribution of stresses that build up during swelling at equilibrium in a 2D model, providing a route toward predicting when this phenomenon of self-fracturing is likely to arise. Applying lessons from indentation theory, poroelasticity, and nonlinear continuum mechanics, we also develop a theoretical framework for understanding how the maximum principal tensile and compressive stresses that develop during swelling are controlled by obstacle geometry and material parameters. These results thus help to shed light on the mechanical principles underlying growth/expansion in environments with obstructions.
Collapse
Affiliation(s)
- Abigail Plummer
- Princeton Center for Complex Materials, Princeton University, Princeton, NJ 08540, USA
| | - Caroline Adkins
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Jean-François Louf
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA.
- Department of Chemical Engineering, Auburn University, Auburn, AL 36849, USA
| | - Andrej Košmrlj
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA.
- Princeton Materials Institute, Princeton University, Princeton, NJ 08544, USA
| | - Sujit S Datta
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA.
| |
Collapse
|
3
|
Kashani A, Cho HJ. The role of poroelastic diffusion in the transient wetting behavior of hydrogels. SOFT MATTER 2024; 20:421-428. [PMID: 38108474 DOI: 10.1039/d3sm01472j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Wetting and water absorption of hydrogels is often encountered in many applications. We seek to understand how wetting behavior can be affected by the time-dependent swelling of hydrogels. We measured the advancing contact angles of water droplets on hydrogels of varying thicknesses where thicker gels absorbed water more slowly. We also observed that, above a threshold advancing speed, water droplets would collapse into a lower contact angle state on the surface. We hypothesized that this collapse threshold speed is a result of competition between the poroelastic diffusion of water into the gel and the advance of the spreading droplet, the thickness of the surface, and the diffusion of water into the gel. Taking the ratio of the diffusion and advancing timescales results in a Peclet number with gel thickness as a characteristic length scale. Our results show that above a Peclet number of around 40, droplets will collapse on the surface across all gel thicknesses, confirming our hypothesis. This work provides simple insight to understand a complex time-dependent wetting phenomenon for a widely used hydrogel.
Collapse
Affiliation(s)
- Amir Kashani
- Department of Mechanical Engineering, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA.
| | - H Jeremy Cho
- Department of Mechanical Engineering, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA.
| |
Collapse
|
4
|
Rajasooriya T, Ogasawara H, Dong Y, Mancuso JN, Salaita K. Force-Triggered Self-Destructive Hydrogels. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2305544. [PMID: 37724392 PMCID: PMC10764057 DOI: 10.1002/adma.202305544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/22/2023] [Indexed: 09/20/2023]
Abstract
Self-destructive polymers (SDPs) are defined as a class of smart polymers that autonomously degrade upon experiencing an external trigger, such as a chemical cue or optical excitation. Because SDPs release the materials trapped inside the network upon degradation, they have potential applications in drug delivery and analytical sensing. However, no known SDPs that respond to external mechanical forces have been reported, as it is fundamentally challenging to create mechano-sensitivity in general and especially so for force levels below those required for classical force-induced bond scission. To address this challenge, the development of force-triggered SDPs composed of DNA crosslinked hydrogels doped with nucleases is described here. Externally applied piconewton forces selectively expose enzymatic cleavage sites within the DNA crosslinks, resulting in rapid polymer self-degradation. The synthesis and the chemical and mechanical characterization of DNA crosslinked hydrogels, as well as the kinetics of force-triggered hydrolysis, are described. As a proof-of-concept, force-triggered and time-dependent rheological changes in the polymer as well as encapsulated nanoparticle release are demonstrated. Finally, that the kinetics of self-destruction are shown to be tuned as a function of nuclease concentration, incubation time, and thermodynamic stability of DNA crosslinkers.
Collapse
Affiliation(s)
| | | | - Yixiao Dong
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
| | | | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30322, USA
| |
Collapse
|
5
|
Hua J, Su M, Sun X, Li J, Sun Y, Qiu H, Shi Y, Pan L. Hydrogel-Based Bioelectronics and Their Applications in Health Monitoring. BIOSENSORS 2023; 13:696. [PMID: 37504095 PMCID: PMC10377104 DOI: 10.3390/bios13070696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/17/2023] [Accepted: 06/26/2023] [Indexed: 07/29/2023]
Abstract
Flexible bioelectronics exhibit promising potential for health monitoring, owing to their soft and stretchable nature. However, the simultaneous improvement of mechanical properties, biocompatibility, and signal-to-noise ratio of these devices for health monitoring poses a significant challenge. Hydrogels, with their loose three-dimensional network structure that encapsulates massive amounts of water, are a potential solution. Through the incorporation of polymers or conductive fillers into the hydrogel and special preparation methods, hydrogels can achieve a unification of excellent properties such as mechanical properties, self-healing, adhesion, and biocompatibility, making them a hot material for health monitoring bioelectronics. Currently, hydrogel-based bioelectronics can be used to fabricate flexible bioelectronics for motion, bioelectric, and biomolecular acquisition for human health monitoring and further clinical applications. This review focuses on materials, devices, and applications for hydrogel-based bioelectronics. The main material properties and research advances of hydrogels for health monitoring bioelectronics are summarized firstly. Then, we provide a focused discussion on hydrogel-based bioelectronics for health monitoring, which are classified as skin-attachable, implantable, or semi-implantable depending on the depth of penetration and the location of the device. Finally, future challenges and opportunities of hydrogel-based bioelectronics for health monitoring are envisioned.
Collapse
Affiliation(s)
- Jiangbo Hua
- Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Mengrui Su
- Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Xidi Sun
- Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Jiean Li
- Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Yuqiong Sun
- Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Hao Qiu
- Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Yi Shi
- Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Lijia Pan
- Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| |
Collapse
|
6
|
Díaz-Marín CD, Zhang L, Lu Z, Alshrah M, Grossman JC, Wang EN. Kinetics of Sorption in Hygroscopic Hydrogels. NANO LETTERS 2022; 22:1100-1107. [PMID: 35061401 DOI: 10.1021/acs.nanolett.1c04216] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Hygroscopic hydrogels hold significant promise for high-performance atmospheric water harvesting, passive cooling, and thermal management. However, a mechanistic understanding of the sorption kinetics of hygroscopic hydrogels remains elusive, impeding an optimized design and broad adoption. Here, we develop a generalized two-concentration model (TCM) to describe the sorption kinetics of hygroscopic hydrogels, where vapor transport in hydrogel micropores and liquid transport in polymer nanopores are coupled through the sorption at the interface. We show that the liquid transport due to the chemical potential gradient in the hydrogel plays an important role in the fast kinetics. The high water uptake is attributed to the expansion of hydrogel during liquid transport. Moreover, we identify key design parameters governing the kinetics, including the initial porosity, hydrogel thickness, and shear modulus. This work provides a generic framework of sorption kinetics, which bridges the knowledge gap between the fundamental transport and practical design of hygroscopic hydrogels.
Collapse
Affiliation(s)
- Carlos D Díaz-Marín
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Lenan Zhang
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Zhengmao Lu
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Mohammed Alshrah
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jeffrey C Grossman
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Evelyn N Wang
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
7
|
Gao Y, Chai NKK, Garakani N, Datta SS, Cho HJ. Scaling laws to predict humidity-induced swelling and stiffness in hydrogels. SOFT MATTER 2021; 17:9893-9900. [PMID: 34605524 DOI: 10.1039/d1sm01186c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
From pasta to biological tissues to contact lenses, gel and gel-like materials inherently soften as they swell with water. In dry, low-relative-humidity environments, these materials stiffen as they de-swell with water. Here, we use semi-dilute polymer theory to develop a simple power-law relationship between hydrogel elastic modulus and swelling. From this relationship, we predict hydrogel stiffness or swelling at arbitrary relative humidities. Our close predictions of properties of hydrogels across three different polymer mesh families at varying crosslinking densities and relative humidities demonstrate the validity and generality of our understanding. This predictive capability enables more rapid material discovery and selection for hydrogel applications in varying humidity environments.
Collapse
Affiliation(s)
- Yiwei Gao
- Department of Mechanical Engineering, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA.
| | - Nicholas K K Chai
- Department of Mechanical Engineering, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA.
| | - Negin Garakani
- Department of Mechanical Engineering, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA.
| | - Sujit S Datta
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA.
| | - H Jeremy Cho
- Department of Mechanical Engineering, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA.
| |
Collapse
|