Smart Dressing Sensor — Biomedical Instrumentation & Clinical Sensing

Abstract — Smart Dressing Sensor

China Prolonged chronic wound healing not only places great stress on patients but also increase the health care burden. Fortunately, the emergence of tissue-engineered dressings has provided a potential solution for these patients. Recently, the relationship between the wound microenvironment and wound healing has been gradually clarified. Therefore, the state of wounds can be roughly ascertained by monitoring the microenvironment in real time. Here, we designed a three-layer integrated smart dressing, including a biomimetic nanofibre membrane, microenvironment sensor and β-cyclodextrin-containing gelatine methacryloyl (GelMA + β-cd) UV-crosslinked hydrogel. The hydrogel helped increase the expression of vascular endothelial growth factor (VEGF) through hypoxia-inducible factor-1α (HIF-1α) to promote neovascularization and wound healing. The microenvironment sensor, combined with the biological dressings, exhibited satisfactory measurement accuracy, stability, durability and biocompatibility. A BLE4.0 antenna was used to receive, display and upload wound microenvironment data in real time. Such integrated smart dressings can not only achieve biological functions but also monitor changes in the wound microenvironment in real time. These dressings can overcome the challenge of not knowing the state of the wound during the healing process and provide support for clinical work.

Sensor Interfacing & Analog Front-End Conditioning

A poor local blood supply is a common feature of chronic wounds, which can have various causes ( Dinh and Veves, 2005 ; Chao and Cheing, 2009 ; Cahn et al., 2016 ). Therefore, determining how to promote wound angiogenesis to accelerate healing is a very important and challenging issue. Angiogenesis in wounds is a complex and multistep process that mainly occurs in the proliferation stage of healing, during which vascular endothelial cells (VECs) proliferate and form a neovascularization network through dynamic changes in shape and behavior. With the rapid development of material science and stem cell tissue engineering, active biological dressings have shown great potential in wound treatment ( Yang et al., 2014 ; Nurhasni et al., 2015 ; Peh et al., 2015 ; Shi et al., 2015 ). Biomedical hydrogels are one example of such dressings.

Bio-Signal Waveform Analysis & Simulation Findings

Compared with traditional dressings, biomedical hydrogels have obvious advantages in terms of, for example, antibacterial properties and biocompatibility ( Shevchenko et al., 2010 ). For example, biomedical hydrogels can better maintain the moist environment of the wound, and their more similar structure to that of the extracellular matrix (ECM) can provide scaffolds for cell adhesion and migration. The three-dimensional (3D) culture of cells based on a hydrogel matrix can better simulate the real ECM environment in vivo . Gelatine methacryloyl (GelMA) has high potential as a tissue engineering material because of its good biological properties and controllable physical properties, and GelMA hydrogels produced by UV crosslinking are widely used in the field of regenerative medicine ( Yue et al., 2015 ). The formation of vascular lumens by endothelial cells is a critical step in the angiogenic process that occurs during invasion and growth of the incipient vascular sprout ( Iruela-Arispe and Davis, 2009 ). Some researchers have used 3D printing technology to carve a lumen structure in GelMA hydrogels and found that these hydrogels could accelerate the proliferation and migration of VECs and promote wound neovascularization ( Lee and Mooney, 2001 ; Aubin et al., 2010 ; Nichol et al., 2010 ; Qi et al., 2010 ). Angiogenesis is a very complex process involving many factors. Vascular extracelluar matrix also plays an important role in the development of the functional circulation ( Davis et al., 2011 ). As a pharmaceutical excipient, β-cyclodextrin (β-cd) is widely used to increase cell permeability, thus increasing the uptake of small molecules such as glucose and nanoparticles. Recently, it has been found that β-cd can also adjust the physical and chemical properties of hydrogels and improve their biocompatibility ( Niu et al., 2018 ; Bezerra et al., 2020 ).

Scope & Clinical Applications

• Real-time multi-parameter vital signs telemetry (ECG, Heart Rate, SpO2, Temperature, Respiration)
• Low-noise Analog Front-End (AFE) conditioning with active Driven Right Leg (DRL) 50 Hz cancellation
• Digital signal processing in MATLAB: Pan-Tompkins QRS detection, FIR/IIR notch, and Continuous Wavelet Transforms
• Finite element tissue bio-electromagnetics and orthopedic mechanical simulations in COMSOL & ANSYS
• Complete Arduino firmware .INO sketches, circuit schematics, and university dissertation reports