Session: Government Agency Student Posters

Paper Number: 173253

Electrical Tissue Adhesives for Strain‐insensitive In‐situ Biosensing 

In-situ biosensing represents a rapidly advancing frontier in biomedical engineering, focusing on the development of biosensors capable of real-time, on-site detection of biomolecules directly from target tissue regions. This emerging approach offers transformative potential in clinical diagnostics by enabling continuous health monitoring, personalized diagnosis, and precisely timed therapeutic interventions. However, the successful implementation of in-situ biosensors is severely hindered by a fundamental challenge: the mechanical mismatch between rigid, non-deformable sensor substrates and the soft, dynamic, and deformable nature of biological tissues. This mismatch can lead to poor tissue integration, signal instability, and even sensor detachment during physiological movements.

To overcome these limitations, we introduce a novel platform based on electronic tissue adhesives (ETAs), a class of multifunctional hydrogels designed to interface seamlessly with biological tissues. These hydrogels offer a unique combination of tissue adhesion, selective molecular transport, and mechanical strain tolerance. Specifically, our ETAs fulfill three essential functions at the bioelectronic interface: (1) they act as robust tissue adhesives by forming covalent and physical interactions with the tissue surface, thereby ensuring stable attachment even under dynamic deformation; (2) they serve as selective-permeable membranes, effectively allowing the transport of target biomarkers such as TNF-α while rejecting high-molecular-weight fouling agents that could compromise sensor accuracy; and (3) they impart mechanical compliance and strain-insensitivity to the biosensor, thereby preserving signal fidelity in mechanically active environments like the oral cavity, gastrointestinal tract, or cardiovascular tissue.

Our methodology integrates material synthesis, device engineering, and in vivo experimentation. The ETA was synthesized using a dual-network hydrogel structure incorporating acrylamide and functionalized carboxyl groups, enabling both covalent bonding and hydrogen bonding with tissue. A selective-permeable hydrogel layer was further incorporated atop a flexible field-effect transistor (FET) biosensor to filter non-target biomolecules. For in vivo testing, the biosensor platform was deployed in the oral cavities of guinea pigs under anesthesia. TNF-α solutions of varying concentrations were injected into the gingival sulcus, and real-time electrical resistance changes were recorded to evaluate sensor performance.

Preliminary results demonstrate the ETA-enabled sensor achieves a detection limit as low as 1 fg/mL for TNF-α with high signal stability (<0.5% variation) under cyclic deformation and varying mechanical loads. The selective hydrogel membrane reduced biological interference by over 90%, and the adhesive hydrogel patch ensured device retention throughout the in vivo experiment without requiring sutures or external fixation.

In conclusion, this study establishes a proof-of-concept for hydrogel-based electronic tissue adhesives as a multifunctional interface for next-generation in-situ biosensing. By addressing the key challenges of biofouling, mechanical instability, and poor biocompatibility, our approach offers a scalable and versatile solution for wearable, implantable, and degradable biosensors across a wide range of biomedical applications.

 

Presenting Author: TSZ HUNG WONG Michigan State University

Presenting Author Biography: NA

Authors:

TSZ HUNG WONG Michigan State University
Weijia Liu Texas A&M University
Jiaoli Li Texas A&M University
Jie Ma MSU
Xinyue Liu MSU
Hajime Sasaki University of michigan
Shaoting Lin MSU