Page 55 - IJB-8-1

RESEARCH ARTICLE

Flexible, Wearable and Fully-printed Smart Patch for

pH and Hydration Sensing in Wounds

Mick Iversen, Monisha Monisha, Shweta Agarwala*

Department of Electrical and Computer Engineering, Finlandsgade 22, Aarhus University, Aarhus, Denmark

Abstract: Wound healing is a complex and dynamic regeneration process, wherein the physical and chemical parameters are
continuously changing. Its management and monitoring can provide immense benefits, especially for bed-ridden patients.
This work reports a low-cost, flexible, and fully printed on-skin patch sensor to measure the change in pH and fluid content in a
wound. Such a bendable sensor can also be easily incorporated in a wound dressing. The sensor consists of different electrodes
printed on polydimethylsiloxane (PDMS) substrate for pH and moisture sensing. The fabricated sensor patch has a sensitivity
of 7.1 ohm/pH for wound pH levels. The hydration sensor results showed that moisture levels on a semi-porous surface can
be quantified through resistance change.

Keywords: Smart patch; Wound management; pH sensor; Hydration sensor; Flexible electronics; Printed electronics

*Correspondence to: Shweta Agarwala, Department of Electrical and Computer Engineering, Finlandsgade 22, Aarhus University, Aarhus,
Denmark; shweta@ece.au.dk

Received: September 30, 2021; Accepted: November 15, 2021; Published Online: December 16, 2021
(This article belongs to the Special Section: 3D Printing and Bioprinting for the Future of Healthcare)
Citation: Iversen M, Monisha M, Agarwala S, 2022, Flexible, Wearable and Fully-Printed Smart Patch for pH and Hydration
Sensing in Wounds. Int J Bioprint, 8(1):447. http:// doi.org/10.18063/ijb.v8i1.447

1. Introduction complex device integration and lack of multifunctional
nanomaterials.
Wound management and its treatment have long been There is a rise in demand for intelligent disposable
considered a problem for healthcare professionals . Both patches that can provide timely and effective wound
[1]
acute and chronic wounds present a threat to global health
and economy. Medical costs associated with wound care management through biochemical and physiological
[10,11]
and treatments range from $28.1 billion to $96.8 billion sensing, such as potential hydrogen (pH) ,
,
,
[12,13]
[14,15]
due to a rise in aging population as well as the incidence temperature [16] hydrogen peroxide [19,20] wound
[17,18]
of diabetes and obesity. There is a clear demand for more exudate volume , lactate , and glucose . The pH
proactive responses that can manage, care or treat wounds level in a wound bed is a key indicative parameter for
[21]
and reduce the burden on healthcare resources . the assessment of the healing progress . The pH of the
[2]
Multifunctional flexible electronic devices have wound is considered to be related to protease activity,
attracted attention owing to their potential applications angiogenesis, and bacterial infection, and therefore,
in sustainable energy, smart displays, healthcare continuous and real-time detection of pH is of great
[22]
monitoring, wearables, human-machine interactions, significance for monitoring wound healing . Healthy
soft robots, artificial skin, etc [3-7] . Among these wearable/ skin is slightly acidic due to organic acid secretion of
on-body devices that are biocompatible and breathable keratinocytes, secretions from sebaceous and sweat
are in huge demand due to their convenience and glands, and the pH fluctuates in alkaline range of 7-8
accessibility . Ongoing research has shown that on- in unhealed wounds [23-28] . Exudate production is also
[8]
body flexible sensors can provide valuable information important for the healing process to keep the wound
to help treat many ailments . Despite the growing need, moist, thereby allowing free movement of the epithelial
[9]
research progress on such devices is slow due to the cells.
© 2021 Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution License, permitting distribution and
reproduction in any medium, provided the original work is properly cited.
41