Fabrication of Dry Electrode for Recording Bio-potentials

Chen

et al. 2011

Sensors

149

130

In the present study, novel dry-contact sensors for measuring electro-encephalography (EEG) signals without any skin preparation are designed, fabricated by an injection molding manufacturing process and experimentally validated. Conventional wet electrodes are commonly used to measure EEG signals; they provide excellent EEG signals subject to proper skin preparation and conductive gel application. However, a series of skin preparation procedures for applying the wet electrodes is always required and usually creates trouble for users. To overcome these drawbacks, novel dry-contact EEG sensors were proposed for potential operation in the presence or absence of hair and without any skin preparation or conductive gel usage. The dry EEG sensors were designed to contact the scalp surface with 17 spring contact probes. Each probe was designed to include a probe head, plunger, spring, and barrel. The 17 probes were inserted into a flexible substrate using a one-time forming process via an established injection molding procedure. With these 17 spring contact probes, the flexible substrate allows for high geometric conformity between the sensor and the irregular scalp surface to maintain low skin-sensor interface impedance. Additionally, the flexible substrate also initiates a sensor buffer effect, eliminating pain when force is applied. The proposed dry EEG sensor was reliable in measuring EEG signals without any skin preparation or conductive gel usage, as compared with the conventional wet electrodes.

Section: Introductionmentioning

confidence: 99%

Design, Fabrication and Experimental Validation of a Novel Dry-Contact Sensor for Measuring Electroencephalography Signals without Skin Preparation

Liao

Chen

et al. 2011

Sensors

149

130

“…The distance between the positive and negative electrodes was 20 mm, and Ag was deposited on the surface of the FXbs electrode in a 0.9% NaCl electrolyte at a constant voltage of 1 V for 10 s, using the constant pressure deposition method. 5 Then, Ag was chlorinated to form AgCl, creating a polarized/ nonpolarized composite structure Ag/AgCl. Figure 1e shows a photograph of the Fructus xanthii-inspired FXbs template,…”

Section: Resultsmentioning

confidence: 99%

“…The surface microneedle array electrodes can avoid changes in skin potential due to skin stretching or electrode movement and can be divided into rigid microneedle array electrodes (RMAEs) and flexible microneedle array electrodes (FMAEs) . RMAEs can penetrate the high-impedance SC without skin pretreatment, thereby making direct contact with low-impedance living epidermal cells to eliminate the need for conductive gels. − However, there is a risk that such electrodes may break in practice, resulting in microneedle fractures entering the body. The main processing method for FMAEs is the processing of metallic patterns or conductive coatings on a flexible substrate, which makes them conductive and stretchable. − Compared to RMAEs, the flexible substrate of FMAEs naturally conforms to skin curves, with better adapting to the skin structure, curvature, and surface hair, resulting in more comfortable, stable, and lower impedance performance …”

Section: Introductionmentioning

confidence: 99%

Fructus Xanthii-Inspired Low Dynamic Noise Dry Bioelectrodes for Surface Monitoring of ECG

Niu

ACS Appl. Mater. Interfaces

et al. 2022

The microstructured surfaces of bioelectrical dry electrodes are important aspects of dry electrode design. However, traditional surfaces for microstructured bioelectrical dry electrodes are costly to produce and require complex fabrication methods. In this study, a novel stacked-template method is proposed for the first time, rapidly producing microstructured dry electrodes at a low cost and with a large surface area. Three types of microstructured Ag/AgCl thermoplastic polyurethane (TPU) electrodes with a Fructus xanthii-inspired barb structure (FXbs) are prepared using this method; then, the dynamic friction, hair interference resistance, electrochemical, and electrocardiogram (ECG) signal acquisition performance of the electrodes are tested, and the dynamic noise characteristics of the electrodes are comprehensively evaluated with simulated instruments. Compared to the plate structure, the dynamic friction coefficient of the FXbs electrode improved by about 38.8%, exhibiting strong hair interference resistance. In addition, the FXbs electrode exhibits low dynamic noise and comparable performance to the wet electrode, in terms of signal acquisition, when it is tested using simulated instruments. Therefore, the prepared FXbs electrode increases the friction coefficient between the electrode and the skin, which effectively resolves issues related to dynamic noise in bioelectrical signals, making it suitable for dynamic measurements.

“…EAs were fabricated by traditional microfabrication technology Wang et al 2011) (Fig. 3), including photolithograghy, deposition and wet etching.…”

Section: Fabrication Of Easmentioning

confidence: 99%

An integrated device for patterning cells and selectively detaching

Yuan

Guo

et al. 2012

Biomed Microdevices

Self Cite

Cell detachment is an ordinary cell behavior, and acts a significant role in numerous physiological processes. In addition, as massive cell groups have specific shapes in vivo, selectively controlling detachment of patterned cells is crucial for both clinical and fundamental research, because it may act as a platform for studying many processes in vitro, and also may be used for tissue engineering. However, it is difficult to first pattern cell groups into isolated islands and then to control their detachment dynamically. Herein, we developed an integrated device that could confine cell groups into various designed shapes, and selectively detach them by applying a low potential. This device contains electrode arrays (EAs) for cell pattern and detachment; and an automatic control system (ACS) connected to a computer for electrically controlling cell detachment. By microfabrication technology, EAs are fabricated on a glass substrate and isolated by surrounding insulating layer (Parylene-C). A new surface modification method is developed: within one step, oligopeptide (CCRRGDWLC) can bond to the gold surface of EAs for cell adhesion or detachment, and PLL-PEG grafts to other parts around the gold surface to resist cell adhesion simultaneously. When a low potential is applied by the ACS to the selected electrodes, cell groups on these electrodes would round up and detach from the surface. Comparing with previous methods, our method can first pattern cells and then selectively detach them. Besides, this device is easy to operate, fast response, and the detaching units are high through-put, and we believe it will be widely used in biological and medical labs.