Sehyun Park
Advisor: Prof. Vladimir V. Tsukruk

will propose a doctoral thesis entitled,

Nanoscale Interfacial Engineering of Two-dimensional nanomaterials for electrophysical and biochemical sensing

On

Friday, July 11 at 11:00 a.m.
Molecular Science and Engineering Building (MoSE)  Room 1222

and

Virtually via Zoom

https://gatech.zoom.us/j/96064483089
Meeting ID 960 6448 3089

Committee Members

Prof. Vladimir Tsukruk (Advisor), MSE

Prof. Peter Hesketh, ME

Prof. Todd Sulchek, ME

Prof. Eric Vogel, MSE

Prof. Shucong Li, MSE

Abstract

This thesis proposal plans for an integrated research framework investigating two interconnected areas critical for next-generation wearable biosensors. First, the fundamental properties of MXene, a novel 2D nanomaterial is explored, with emphasis on optimizing its mechanical flexibility, electrical conductivity, and interfacial adhesion characteristics for seamless skin integration. The approach employs mathematical modeling of skin texture and deformation dynamics to precisely tune MXene thickness, enabling it to match skin's viscoelastic behavior while maintaining structural integrity during movement and under varying environmental conditions including high humidity and extreme temperatures. Second, this study investigates biological analyte detection science through systematic exploration of reaction mechanisms, optimization of material selection criteria, and implementation of advanced surface functionalization strategies. This component focuses on identifying and targeting specific functional groups in biochemicals, culminating in the development of enhanced chemical-sensitive field effect transistors (FETs) for biological analyte detection as an application.

Central to this effort are two thrusts: 1) The integration of MXene and parylene combines their complementary properties to solve challenges in wearable electrophysiology. MXenes offer metallic conductivity, hydrophilicity, and biocompatibility for stable skin coupling, while parylene provides a hydrophobic, flexible, and inert moisture barrier. This synergy creates dual functionality: MXene conforms to skin via van der Waals forces, and parylene prevents water ingress and delamination. Theoretical modeling guides thickness optimization to match skin’s modulus, enhancing nanoscale conformability and reducing impedance. Ultrathin, skin-conformal nano-electrodes will be developed using this MXene-parylene design. 2) The sensing mechanism relies on functionalized surfaces, where self-assembled monolayers (SAMs) with tailored terminal groups chemically bond to oxide-rich semiconductor material (In2O3), creating stable interfaces for probe immobilization. The biorecognition layer specifically interacts with functional groups on analytes-such as tertiary amines-through hydrogen bonding, altering local charge density. Surface chemistry optimization balances probe density and steric accessibility, often using mixed SAMs with spacer molecules. Target selectivity is enhanced by converting amines to derivatives like N-oxides, amides, which improve binding affinity. Material selection prioritizes semiconductors with native oxide layers to facilitate SAM anchoring, also considering ease of fabrication. A field-effect transistor-based sensor structure will be developed using these SAM methods and In2O3.

Overall, this work will study fundamental factors of 1) making conformal contact on skin by engineering nanoscale materials properties and interface mechanics, thereby overcoming current limitations in device performance, reliability, and fabrication methods. 2) surface functionalization to enhance sensitivity and reliability of target molecules. The resulting technologies will offer enhanced signal fidelity, environmental robustness, and ultrasensitive detection capabilities, paving the way for innovative solutions in healthcare monitoring, flexible electronics, and biochemical sensing.