A novel biorecognition receptor Citropin-A modified impedimetric biosensor for detection of LNCaP prostate cancer cells.

In this study, Citropin-A (Cit-A) as a biorecognition receptor was used for the first time to develop electrochemical impedance spectroscopy (EIS) based biosensor for the detection of Lymph Node Carcinoma of the Prostate (LNCaP) cancer cells. The biosensor was engineered by modification of a gold electrode (AuE) with cysteamine (Cys), Poliamidoamin (PAMAM (G4)) dendrimers, avidin, and biotinylated Cit-A, respectively. The detection time of the LNCaP cells was determined as 300 s by chronoimpedance (CI). Chronoimpedance also provided an exact detection time to avoid non-specific adsorptions. The biosensor showed good linearity between 1500 cells/L and 12000 cells/L, limit of detection (LOD), and limit of quantification (LOQ) values were 518 cells/L and 1570 cells/L, respectively.

Impedimetric Single Carbon Fiber Electrode for Ultrasensitive Detection of Staphylococcus aureus Pathogen DNAs in Breast Milk by CRISPR Technology.

This study introduces a novel biosensing approach for the detection of pathogen DNA in breast milk utilizing single carbon fiber electrodes (SCFE) enhanced with MXene nanomaterial layers. The primary innovation lies in the modification of SCFE with MXenes to increase the electrode's surface area, followed by surface activation for the immobilization of dCas9-sgRNA complexes. This modification aims to leverage the unique properties of MXenes and the selective binding capability of the CRISPR technology for efficient and specific pathogen detection. Electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) analyses were employed to characterize the electrode modifications and the immobilization process, demonstrating the successful enhancement of biosensor performance. This study further optimized the chronoimpedimetric detection method to achieve rapid, sensitive, and selective detection of Staphylococcus aureus (SAu) DNA in breast milk, with a notable detection time of 60 s in real samples. The biosensor demonstrated high selectivity and sensitivity, with a linear detection range between 50 and 6000 fM and a limit of detection (LOD) of 14.5 fM. The reproducibility and stability of the biosensor were also confirmed through multiple tests, showing promising potential for clinical and public health applications.

Molecularly Imprinted Microspheres-Modified Impedimetric Sensor Systems for Distinguished Determination of Glycosaminoglycan.

This study determined isomeric molecules by employing molecular imprinting technology (MIP) and electrochemical impedance spectroscopy (EIS). In order to increase surface area to obtain more sensitive sensor technology, ex situ precipitation polymerization was carried out to produce microspheres. These microspheres were placed on pyrrole-modified carbon electrodes. Acrylamide, as monomer, was polymerized by cross-linker trimethylolpropane trimethacrylate (TRIM) and Azobisisobutyronitrile (AIBN) as initiator and as template molecules; chondroitin sulfate (CS) and dermatane sulfate (DS) were used. Performances of the electrodes were determined as follows, CS and DS sensor, respectively; calibration curves were calculated between 50 to 500 ng/mL and 50 to 600 ng, R2 = 0.9942 ± 0.0029 and R2 = 0.9824 ± 0.0083, LOD and LOQ were 15.19 ng/mL, 46.03 ng/mL, and 32.56 ng/mL, 102.82 ng/mL, respectively. The characterization of polymers was carried out by X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared (FTIR), and Scanning Electron Microscopy (SEM). The applicability of the optimized sensor systems to real samples was examined in urine samples and the systems were tested by LC-MS/MS method. Sensors showed a good correlation with tandem mass spectrometry.

Non-invasive cortisol detection in saliva by using molecularly cortisol imprinted fullerene-acrylamide modified screen printed electrodes.

In this study, we developed an impedimetric sensor system by using molecularly cortisol imprinted acrylamide polymers on fullerene modified carbon electrode to detect cortisol in real saliva samples. The polymer layer was formed on fullerene modified screen printed carbon electrodes with the ratio of 1:2 (cortisol:acrylamide) and ammonium persulfate (APS) was used as the initiator of polymerization. The sensor surface was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Scanning Electron Microscopy (SEM). Performances of the electrode were determined as follows; calibration curve was calculated between 0.5 nM and 64 nM, R2 = 0.9939, LOD and LOQ were 0.14 nM and 0.44 nM, respectively. Real human saliva samples were obtained from 15 participants between 25 and 32 ages regardless of gender. The samples, which were collected at least 30 min after waking up and the new sensor method analysis were compared tandem mass spectroscopy coupled liquid chromatography system (LC-MS/MS). The sensor analysis showed a significant correlation with LC-MS/MS results (R2 = 0.9727).