Bioelectrochemistry最新文献

Highly stable calcium ion selective electrodes (Ca²⁺-ISEs) were developed by drop-casting a layer of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT: PSS) as an ion-to-electron transfer layer onto Au electrode. The conductive PEDOT: PSS ink was prepared using a metastable liquid-liquid contact (MLLC) doping method, which induced phase separation, removed excess PSS, and significantly enhanced charge transfer kinetics and conductivity. The resulting Ca²⁺-ISEs exhibited excellent electrochemical performance. Potentiometric studies revealed a significant sensitivity of 33.1 ± 0.98 mV/decade (N = 3) with a high potential stability of 3.16 ± 2.53 μV/h. Importantly, Ca²⁺-ISEs combined with the constant potential coulometry method, the lower detection limit was optimized to 8.527 × 10^-8 M (LOD = 3σ/s, N = 3). The performance of the Ca²⁺-ISE system was evaluated in inactivated fetal bovine serum using constant potential coulometry, demonstrating the highest measurement accuracy compared to potentiometric and chronoamperometric. The enhanced PEDOT: PSS-MLLC based Ca²⁺-ISEs combined with the constant potential coulometry method developed in this research demonstrate considerable potential for clinical applications in blood ion analysis.

Bloodstream bacterial infections, a major health concern due to rising sepsis rates, require prompt, cost-effective diagnostics. Conventional methods, like CO₂-based transduction, face challenges such as volatile metabolites, delayed gas-phase signaling, and the need for additional instruments, whereas electrochemical sensors provide rapid, sensitive, and efficient real-time detection. In this study, we developed a bioreceptor-free Prussian blue (PB) sensor platform for real-time bacterial growth monitoring in blood culture. PB thin films were electrodeposited onto a screen-printed carbon electrode (SPCE) via cyclic voltammetry (CV) technique under optimal conditions. The electrochemical performance of PB/SPCE was assessed using differential pulse voltammetry (DPV) against exoelectrogenic bacteria, including E. coli, P. aeruginosa, S. aureus, and E. faecalis. The proposed sensor exhibited surface-controlled electrochemical kinetics and bacteria-driven metal reduction from PB to Prussian white (PW), facilitated by extracellular electron transfer (EET). It showed significant sensitivity with an extensive detection range of 10²-10⁸ CFU/mL for E. coli and S. aureus, and 10³-10⁸ CFU/mL for P. aeruginosa and E. faecalis, with reliable detection limits. The sensor accessed the viability of the pathogen within 3 hrs, offering a rapid, efficient alternative to traditional, labor-intensive methods for blood-based diagnostics.

The importance of developing multifunctional nanomaterials for sensing technologies is increasing with the arrival of nanotechnology. In this study, we describe the introduction of novel nanoprobe electro-active material into the architecture of an electrochemical immuno-sensor. Based on the electrochemical immuno-sensor, functionalized tin oxide/graphitic carbon nitride nanocomposite (fSnO₂/g-C₃N₄) was synthesized and then analyte specific anti-aflatoxin M₁ monoclonal antibody (AFM₁-ab) combined to form an electro-active nanoprobe (fSnO₂/g-C₃N₄/AFM₁-ab). First, aflatoxin M₁ (AFM₁) conjugated bovine serum albumin (BSA-AFM₁) was electro-oxidized on the surface of carbon fiber (CF) followed by the consequent addition of nanoprobe. The formation of nanocomposite was substantiated through various characterization techniques, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), Thermogravimetric analysis (TGA) and Dynamic light scattering (DLS). Immuno-sensor fabrication was characterized via Field emission scanning electron microscopy (FE-SEM), optical microscope images, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). This immuno-sensor demonstrated good reproducibility, selectivity, specificity and sensitivity for AFM₁ (LOD of 0.03 ng mL^-1). Following spiking, this immuno-sensor produced good recovery values in the range of 94-96 % against real sample, such as milk. The development of sophisticated sensing methods for a range of analytes can greatly benefit from the widespread application of this innovative immuno-sensing approach.

In this work, the electrochemical biosensor based on the subtle combination of terminal deoxynucleotidyl transferase (TdT), CRISPR/Cas14a, and magnetic nanoparticles (MNPs) was developed for the detection of nasopharyngeal carcinoma (NPC)-derived exosomes. Due to the synergistic effect of the following factors: the powerful elongation capacity of TdT for single-stranded DNA (ssDNA) with 3-hydroxy terminus, the outstanding trans-cleavage ability of CRISPR/Cas14a specifcally activated by the crRNA binding to target DNA, and the excellent separation ability of MNPs, the developed electrochemical biosensor exhibited high sensitivity for the detection of NPC-derived exosome, with a linear range from 6.0 × 10² ∼ 1.0 × 10⁵ particles/mL and a limit of detection as lown as 80 particles/mL. In addition, this electrochemical biosensor successfully distinguished exosomes from NPC patients and healthy individuals. This electrochemical biosensor opens up a new pathway for the early diagnosis of NPC. Abbreviations: NPC, Nasopharyngeal carcinoma; CRISPR/Cas, Clustered regularly interspaced short palindromic repeats/CRISPR-associated proteins system; PAMs, Protospacer adjacent motifs; RCA, Rolling circle amplification; CHA, Catalytic hairpin assembly; LAMP, Loop-mediated isothermal amplification; TdT, Terminal deoxynucleotidyl transferase; SgRNA, Single guide RNA.

To provide accurate diagnostic evidence for early hepatitis B virus (HBV) infection-related diseases, this study targeted HBV DNA as an analyte, where a sandwich-type electrochemical DNA sensor based on gold nanoparticles/reduced graphene oxide (Au NPs/ERGO) and cerium oxide/gold-platinum nanoparticles (CeO₂/AuPt NPs) was constructed. Au NPs/ERGO composite nanomaterials were first synthesized on the surface of a glass carbon electrode using electrochemical co-reduction, which significantly improved the specific surface area and electrical conductivity of the electrode. Further specific hybridization of target HBV-DNA was performed by combining capture probe DNA (S1-DNA) bound to AuNPs/ERGO with CeO₂/AuPt modified signal probe DNA (S2-DNA). Leveraging the excellent H₂O₂ catalytic activity of the CeO₂/AuPt nanocomposite, the constructed sandwich-type electrochemical DNA sensor was used to detect HBV DNA. By optimizing the detection conditions, the sensor showed a good linear response in the range of 1 fmol/L to 1 nmol/L, with a detection limit as low as 0.36 fmol/L. The sensor had good specificity, repeatability, and stability. Further, spiked recovery experiments of actual serum samples showed recoveries ranging from 98.7 % to 102.7 %, and the relative standard deviations were all lower than 4.77 %. This study provides a new method for the detection of HBV DNA with potential clinical applications.

Owing to fast SARS-CoV-2 mutations, biosensors employing antibodies as biorecognition elements have presented problems with sensitivity and accuracy. To face these challenges, antibodies can be replaced with the human angiotensin converting enzyme 2 (ACE-2), where it has been shown that the affinity between ACE-2 and the receptor binding domain (RBD) increases with the emergence of new variants. Herein, we report on Ni-doped ZnO nanorod electrochemical biosensors employing an ACE-2 peptide (IEEQAKTFLDKFNHEAEDLFYQS-NH₂) as a biorecognition element for detecting Spike (S) Wild-Type (WT) protein. The electrode was fully characterized in terms of electrochemical and physical properties. The sensor showed high cross reactivity with Spike protein B.1.1.7 and Spike protein B.1.351. Still, there was no cross reactivity with the Nucleocapsid protein WT, showing that the biosensor can identify ancestral WT S protein and S protein variants of concern. The device exhibited a LOD of 60.13 ng mL^-1 across an S protein WT concentration range from 200 ng mL^-1 to 1000 ng mL^-1 and a LOQ of 182.22 ng mL^-1. The calculated sensitivity and specificity were 88.88 and 100 %, respectively. These results proved that the Ni-ZnO sensor has promising prospects for SARS-CoV-2 detection and diagnosis of other viruses, employing peptides as biorecognition elements.

Microbiologically influenced corrosion (MIC) affects offshore production activities severely. Although adding biocides is a simple method, it can cause environmental damage over time. Using green biocide enhancers is a viable strategy to reduce the amount of biocides. In this study, four novel peptides, named Peptide T/Tc/Ts/Tcs, were designed by a natural peptide extracted from the Arctic sea squirt to enhance the efficacy of tetrakis hydroxymethyl phosphonium sulfate (THPS) in mitigating the biocorrosion of EH36 steel caused by Desulfovibrio ferrophilus. The combination of 40 ppm THPS and 100 nM Peptide T/Tc/Ts/Tcs reduced the corrosion rates of EH36 steel by 68 %, 71 %, 86 %, and 90 % after the 7-d incubation, respectively. Notably, 40 ppm THPS + 100 nM Peptide Ts/Tcs achieved similar antimicrobial and biocorrosion mitigation effects as 100 ppm THPS. It suggests that optimizing the cationic and hydrophobic properties of peptides could enhance the bactericidal properties of biocides.

Argonaute 2 (Ago2) is a crucial enzyme in the RNA interference (RNAi) pathway, essential for gene silencing via the cleavage of target messenger RNA (mRNA) mediated by microRNA (miRNA) or small interfering RNA (siRNA). The activity of Ago2 is a significant biomarker for various diseases, including cancer and viral infections, necessitating precise monitoring techniques. Traditional methods for detecting Ago2 activity are often cumbersome and lack the necessary sensitivity and specificity for low-abundance targets in complex samples. This study presents an innovative biosensor utilizing electrochemiluminescence (ECL) technology combined with the SAHARA (Split Activator for Highly Accessible RNA Analysis) CRISPR-Cas12a system to detect Ago2 activity with high sensitivity and specificity. The introduction of Blocker RNA in the activation mechanism enhances the specificity of CRISPR-Cas12a, ensuring accurate signal generation. The dual signal amplification strategy, combining RISC-assisted and CRISPR-Cas12a-mediated cleavage, enhances the biosensor's sensitivity. The developed ECL biosensor demonstrated a remarkable limit of detection (LOD) of 0.145 aM, along with excellent precision, stability, and specificity. These attributes make it a powerful tool for detecting Ago2 activity in clinical diagnostics and research settings.