An eco-friendly MIP-solid surface fluorescence immunosensor for detection of CA 19-9 tumor marker using Ni nanocluster as an emitter labels

Graphitic carbon nitride/1-pyrenebutyric acid N-hydroxysuccinimide/polythiophene nanocomposite photoelectrochemical biosensor for CA 19-9 detection

A photoelectrochemical (PEC) biosensor composed entirely of carbon nanomaterials was synthesized to detect carbohydrate antigen 19-9 (CA 19-9). The biosensor platform integrated graphitic carbon nitride (GCN), known for its light sensitivity, polythiophene (PTh), an organic conductive and optically active material, and 1-pyrenebutyric acid N-hydroxysuccinimide (PBASE), which functions both as a biolinker to conjugate CA 19-9 antibody and antigen and as an electron mediator to facilitate electron transfer from GCN to PTh. The formation of a Schottky heterojunction between PTh and GCN reduced the bandgap of GCN from 2.66 to 1.96 eV, which enhanced transfer of photogenerated electrons for cathodic photocurrent generation. The improvement of charge transfer due to heterojunction formation and π-π stacking between GCN and the pyrene group of PBASE is confirmed by cyclic voltammetry (CV), electron impedance spectroscopy (EIS), and chronoamperometry (CA) findings. The highest current of 1.31 μA is observed for combination of 5 wt% PTh with a GCN/PBASE ratio of 1:0.5. Besides evaluating the electron mobility of GCN/PBASE/PTh, CV, EIS, and CA were also used to evaluate the sensor performance. Optimization studies revealed that 0.6 μg of CA 19-9 antibody and 1 h of antigen-antibody immobilization time significantly improved the biosensor response. The GCN/PBASE/PTh biosensor demonstrated high sensitivity to CA 19-9 antigen across a concentration of 50-1000 U/ml and a detection limit as low as 0.052 U/ml. The reported working range is within the limits required for diagnostic testing of patients with hepatic and heart problems as well as for post-treatment monitoring of colorectal and pancreatic cancer patients.

A dual-electrode label-free immunosensor based on in situ prepared Au-MoO3-Chi/porous graphene nanoparticles for point-of-care detection of cholangiocarcinoma

A novel label-free electrochemical immunosensor was prepared for the detection of carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) as biomarkers of cholangiocarcinoma (CCA). A nanocomposite of gold nanoparticles, molybdenum trioxide, and chitosan (Au-MoO3-Chi) was layer-by-layer assembled on the porous graphene (PG) modified a dual screen-printed electrode using a self-assembling technique, which increased surface area and conductivity and enhanced the adsorption of immobilized antibodies. The stepwise self-assembling procedure of the modified electrode was further characterized morphologically and functionally. The electroanalytical detection of biomarkers was based on the interaction between the antibody and antigen of each marker via linear sweep voltammetry using ferrocyanide/ferricyanide as an electrochemical redox indicator. Under optimized conditions, the fabricated immunosensor showed linear relationships between current change (ΔI) and antigen concentrations in two ranges: 0.0025-0.1 U mL-1 and 0.1-1.0 U mL-1 for CA19-9, and 0.001-0.01 ng mL-1 and 0.01-1.0 ng mL-1 for CEA. The limits of detection (LOD) were 1.0 mU mL-1 for CA19-9 and 0.5 pg mL-1 for CEA. Limits of quantitation (LOQ) were 3.3 mU mL-1 for CA19-9 and 1.6 pg mL-1 for CEA. The selectivity of the developed immunosensor was tested on mixtures of antigens and was then successfully applied to determine CA19-9 and CEA in human serum samples, producing satisfactory results consistent with the clinical method.

Ultrasensitive immunosensor for monitoring of CA 19-9 pancreatic cancer marker using electrolyte-gated TiS3 nanoribbons field-effect transistor

Measuring CA 19-9 antigen level is critical for early diagnosis of pancreatic cancer, monitoring the treatment process, and predicting disease recurrence. The purpose of this research is to assess the application of novel few-layered TiS₃ nanoribbons material as a channel material in electrolyte-gated field-effect transistor immunosensor for rapid detection of CA 19-9 antigen as a cancer marker. Accordingly, TiS₃ nanoribbons were produced through liquid-phase exfoliation of as-synthesized TiS₃ whiskers in N, N-dimethylformamide. Then, dispersed TiS₃ nanoribbons were drop cast onto the FET surface to form an active channel material between source and drain electrodes. Subsequently, the channel surface was modified by utilizing 1-naphthylamine (NA) and glutaraldehyde (GA) to strengthen the binding of monoclonal antibody 19-9 to TiS₃ nanoribbons. Spectroscopic and microscopic methods were utilized for comprehensive characterizations. Electrical characterization of electrolyte-gated TiS₃ nanoribbons field-effect transistor represented a depletion-mode n-type behavior with field-effect mobility of 0.059 cm²/Vs, current on/off ratio of 10.88 and subthreshold swing (SS) of 450.9 mV/decade. With increasing in CA 19-9 antigen concentration from 1.0 × 10^-12 U/mL to 1.0 × 10^-5 U/mL, a decrease in the drain current occurred with high sensitivity of 0.04 μA/decade and a detection limit of 1.3 × 10^-13 U/mL. Additionally, the proposed TiS₃ nanoribbons FET immunosensor exhibited outstanding selectivity, and its good performance was compared with an enzyme-linked immunosorbent assay (ELISA) for spiked real human serum samples. The good and satisfactory obtained results of the proposed immunosensor suggest that the developed platform can be a superb candidate for cancer diagnosis and therapeutic monitoring.

Recent Trends in Biosensing and Diagnostic Methods for Novel Cancer Biomarkers

Cancer is one of the major public health issues in the world. It has become the second leading cause of death, with approximately 75% of cancer deaths transpiring in low- or middle-income countries. It causes a heavy global economic cost estimated at more than a trillion dollars per year. The most common cancers are breast, colon, rectum, prostate, and lung cancers. Many of these cancers can be treated effectively and cured if detected at the primary stage. Nowadays, around 50% of cancers are detected at late stages, leading to serious health complications and death. Early diagnosis of cancer diseases substantially increases the efficient treatment and high chances of survival. Biosensors are one of the potential screening methodologies useful in the early screening of cancer biomarkers. This review summarizes the recent findings about novel cancer biomarkers and their advantages over traditional biomarkers, and novel biosensing and diagnostic methods for them; thus, this review may be helpful in the early recognition and monitoring of treatment response of various human cancers.

Electrochemical Immunoassay for Tumor Marker CA19-9 Detection Based on Self-Assembled Monolayer

A CA19-9 electrochemical immunosensor was constructed using a hybrid self-assembled membrane modified with a gold electrode and applied to detect real samples. Hybrid self-assembled membranes were selected for electrode modification and used to detect antigens. First, the pretreated working electrodes were placed in a 3-mercaptopropionic acid (MPA)/β-mercaptoethanol (ME) mixture for 24 h for self-assembly. The electrodes were then placed in an EDC/NHS mixture for 1 h. Layer modification was performed by stepwise dropwise addition of CA19-9 antibody, BSA, and antigen. Differential pulse voltammetry was used to characterize this immunosensor preparation process. The assembled electrochemical immunosensor enables linear detection in the concentration range of 0.05–500 U/mL of CA19-9, and the detection limit was calculated as 0.01 U/mL. The results of the specificity measurement test showed that the signal change of the interfering substance was much lower than the response value of the detected antigen, indicating that the sensor has good specificity and strong anti-interference ability. The repeatability test results showed that the relative standard deviations were less than 5%, showing good accuracy and precision. The CA19-9 electrochemical immunosensor was used for the actual sample detection, and the experimental results of the standard serum addition method showed that the RSD values of the test concentrations were all less than 10%. The recoveries were 102.4–115.0%, indicating that the assay has high precision, good accuracy, and high potential application value.

Cellulose-based hydrogel on quantum dots with molecularly imprinted polymers for the detection of CA19-9 protein cancer biomarker

Molecularly imprinted polymers MIPs were successfully assembled around quantum dots (QDs), for the detection of the protein biomarker CA19-9 associated to pancreatic cancer (PC). These imprinted materials MIP@QDs were incorporated within the cellulose hydrogel with retention of its conformational structure inside the binding cavities. The concept is to use MIPs which function as the biorecognition elements, conjugated to cadmium telluride QDs as the sensing system. The excitation wavelength was set to 477 nm and the fluorescence signal was measured at its maximum intensity, with an emission range between 530 and 780 nm. The fluorescence quenching of the imprinted cellulose hydrogels occurred with increasing concentrations of CA19-9, showing linearity in the range 2.76 × 10 ^-2 - 5.23 × 10 ² U/ml, in a 1000-fold diluted human serum. Replicates of the imprinted hydrogel show a linear response below the cut-off values for pancreatic cancer diagnosis (< 23 U/ml), a limit of detection of 1.58 × 10 ^-3 U/ml and an imprinting factor (IF) of 1.76. In addition to the fact that the imprinted cellulose hydrogel displays good stability and selectivity towards CA19-9 when compared with the non-imprinted controls, the conjugation of MIPs to QDs increases the sensitivity of the system for an optical detection method towards ranges within clinical significance. This fact shows potential for the imprinted hydrogel to be applied as a sensitive, low-cost format for point-of-care tests (PoCTs).