Additive Blending Effects on PEDOT:PSS Composite Films for Wearable Organic Electrochemical Transistors

Organic electrochemical transistors (OECTs) employing conductive polymers (CPs) have gained remarkable prominence and have undergone extensive advancements in wearable and implantable bioelectronic applications in recent years. Among the diverse arrays of CPs, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a common choice for the active-layer channel in p-type OECTs, showing a remarkably high transconductance for the high amplification of signals in biosensing applications. This investigation focuses on the novel engineering of PEDOT:PSS composite materials by seamlessly integrating several additives, namely, dimethyl sulfoxide (DMSO), (3-glycidyloxypropyl)trimethoxysilane (GOPS), and a nonionic fluorosurfactant (NIFS), to fine-tune their electrical conductivity, self-healing capability, and stretchability. To elucidate the intricate influences of the DMSO, GOPS, and NIFS additives on the formation of PEDOT:PSS composite films, theoretical calculations were performed, encompassing the solubility parameters and surface energies of the constituent components of the NIFS, PEDOT, PSS, and PSS-GOPS polymers. Furthermore, we conducted a comprehensive array of material analyses, which reveal the intricacies of the phase separation phenomenon and its interaction with the materials’ characteristics. Our research identified the optimal composition for the PEDOT:PSS composite films, characterized by outstanding self-healing and stretchable capabilities. This composition has proven to be highly effective for constructing an active-layer channel in the form of OECT-based biosensors fabricated onto polydimethylsiloxane substrates for detecting dopamine. Overall, these findings represent significant progress in the application of PEDOT:PSS composite films in wearable bioelectronics and pave the way for the development of state-of-the-art biosensing technologies

Descriptive statistics and correlations among the study variables (N = 189).

Descriptive statistics and correlations among the study variables (N = 189).</p

Results of moderated regression in predicting NSIs preventing behaviors.

Results of moderated regression in predicting NSIs preventing behaviors.</p

Interaction between self-efficacy to prevent NSIs and job demands in predicting NSIs prevention behaviours.

Interaction between self-efficacy to prevent NSIs and job demands in predicting NSIs prevention behaviours.</p

Primers and conditions for PCR amplification of <i>FBXO7</i> cDNA and genomic DNA.

<p>The <i>Pst</i>I restriction site was created by PCR using a mismatch primer. For Y52C and M115I amplification, the underlines in the primer sequence and enzyme recognition site indicate the mismatch nucleotide and polymorphic site, respectively. For cDNA cloning, the underlines in the primer sequence indicate the introduced <i>Hin</i>dIII, <i>Age</i>I and <i>Xho</i>I restriction sites.</p

Flp-In SH-SY5Y cells with induced FBXO7 expression and neuronal phenotype.

<p>(A) Western blot analysis of FBXO7-EGFP protein level using FBXO7 antibody and anti-actin antibody as loading control after 2 days induction with doxycycline (+ Dox) or not (- Dox). (B) Representative microscopic images of neuronal differentiated Tyr52 and Cys52 cells (for 21 days). Nuclei were counterstained with DAPI (blue). Neuronal total outgrowth was quantified in Tyr52 and Cys52 cells with induced differentiation for 7–21 days. Data are represented as the means ± S.D. of three separate experiments.</p

Co-immunoprecipitation of Tyr52 or Cys52 FBXO7-EGFP protein and ubiquitination of TRAF2.

<p>(A) HEK-293T cells were transiently transfected with Tyr52 or Cys52 FBXO7-EGFP construct. After 48 h, cell lysates were prepared (Input, left panel) and immunoprecipitations (IP, right panel) were performed with anti-TRAF2 antibody. Normal IgG was used as a negative control for IP. Cell lysates and immunoprecipitates were analyzed with anti-EGFP, anti-TRAF2, anti-ubiquitin or anti-actin antibody. (B) Quantification of immunoprecipitated FBXO7-EGFP, TRAF2 and ubiquitin in HEK-293T cells transiently transfected with Tyr52 or Cys52 FBXO7-EGFP construct for 2 days. Data are represented as the means ± S.D. of three separate experiments.</p

Sensitive Detection of Sweat Cortisol Using an Organic Electrochemical Transistor Featuring Nanostructured Poly(3,4-Ethylenedioxythiophene) Derivatives in the Channel Layer

In this study, we examined the influence of functionalized poly­(3,4-ethylenedioxythiophene) (PEDOT) nanostructures decorated on the channel layer of an organic electrochemical transistor (OECT) for the detection of sweat cortisol, an adrenocorticosteroid stress hormone. The OECT device featured a bilayer channel confined by a PEDOT:polystyrenesulfonate (PSS) underlayer and a nanostructure-decorated upper layer engineered from the monomers EDOT-COOH and EDOT-EG3 through template-free electrochemical polymerization. This molecular design allowed antibody conjugation using 1-ethyl-3-(3-dimethylaminopropyl)­carbodiimide/N-hydroxysulfosuccinimide coupling through the carboxylic acid side chain, with EDOT-EG3 known to minimize nonspecific binding of biomolecules. We also engineered an OECT device having a channel area without any nanostructures to gain insight into the effect of the nanostructures on cortisol sensing. Our new nanostructure-embedded OECT device facilitated real-time detection of cortisol at concentrations ranging from 1 fg/mL to 1 μg/mL with a detection limit of 0.0088 fg/mL with good linearity (R2 = 0.9566), in addition to excellent selectivity toward cortisol among other structurally similar interfering compounds and high stability and reproducibility. With its rapid response for the detection of 100 ng/mL cortisol-spiked artificial sweat, this nanostructure-decorated OECT device has potential clinical practicality and utility in wearable sensors for future healthcare applications

Genotype and allele distributions and association analysis.

<p>Odds ratios were calculated by comparing each value with the major common genotype or allele.</p

Western blot analysis of NF-κB signaling pathway protein TRAF2.

<p>HEK-293T cells were tranfected with Tyr52 or Cys52 FBXO7 construct and harvested after two days. Transfected FBXO7-EGFP or endogenous TRAF2 protein was detected using specific antibodies and anti-actin and anti-neomycin antibodies as the loading and the transfection control, respectively. Data are represented as the means ± S.D. of three separate experiments.</p