Dual-signal output biosensor for the detection of program death-ligand 1 and therapy progress monitoring of cancer.

A disposable dual-output biosensor to detect program death-ligand 1 (PD-L1) was developed for immunotherapy progress monitoring and early cancer detection in a single experimental setup. The aptamer probe was assembled on rGO composited with carboxylated terthiophene polymer (rGO-pTBA) to specifically capture PD-L1 protein labeled with a new redox mediator, ortho-amino phenol para sulphonic acid, for amperometric detection. Each sensing layer was characterized through electrochemical and surface analysis experiments, then confirmed the sensing performance. The calibration plots for the standard PD-L1 protein detection revealed two dynamic ranges of 0.5-100.0 pM and 100.0-500.0 pM, where the detection limit was 0.20 ± 0.001 pM (RSD ≤5.2%) by amperometry. The sensor reliability was evaluated by detecting A549 lung cancer cell-secreted PD-L1 and clinically relevant serum levels of soluble PD-L1 (sPD-L1) using both detection methods. In addition, therapeutic trials were studied through the quantification of sPD-L1 levels for a small cohort of lung cancer patients. A significantly higher level of sPD-L1 was observed for patients (221.6-240.4 pM) compared to healthy individuals (16.2-19.6 pM). After immunotherapy, the patients' PD-L1 level decreased to the range of 126.7-141.2 pM. The results indicated that therapy monitoring was successfully done using both the proposed methods. Additionally, based on a comparative study on immune checkpoint-related proteins, PD-L1 is a more effective biomarker than granzyme B and interferon-gamma.

Comparison of partitioned survival modeling with state transition modeling approaches with or without consideration of brain metastasis: a case study of Osimertinib versus pemetrexed-platinum.

BACKGROUND: The partitioned survival model (PSM) and the state transition model (STM) are widely used in cost-effectiveness analyses of anticancer drugs. Using different modeling approaches with or without consideration of brain metastasis, we compared the quality-adjusted life-year (QALY) estimates of Osimertinib and pemetrexed-platinum in advanced non-small cell lung cancer with epidermal growth factor receptor mutations. METHODS: We constructed three economic models using parametric curves fitted to patient-level data from the National Health Insurance Review and Assessment claims database from 2009 to 2020. PSM and 3-health state transition model (3-STM) consist of three health states: progression-free, post-progression, and death. The 5-health state transition model (5-STM) has two additional health states (brain metastasis with continuing initial therapy, and with subsequent therapy). Time-dependent transition probabilities were calculated in the state transition models. The incremental life-year (LY) and QALY between the Osimertinib and pemetrexed-platinum cohorts for each modeling approach were estimated over seven years. RESULTS: The PSM and 3-STM produced similar incremental LY (0.889 and 0.899, respectively) and QALY (0.827 and 0.840, respectively). However, 5-STM, which considered brain metastasis as separate health states, yielded a slightly higher incremental LY (0.910) but lower incremental QALY (0.695) than PSM and 3-STM. CONCLUSIONS: Our findings indicate that incorporating additional health states such as brain metastases into economic models can have a considerable impact on incremental QALY estimates. To ensure appropriate health technology assessment decisions, comparison and justification of different modeling approaches are recommended in the economic evaluation of anticancer drugs.

Conducting polymer composite-based biosensing materials for the diagnosis of lung cancer: A review.

The development of a simple and fast cancer detection method is crucial since early diagnosis is a key factor in increasing survival rates for lung cancer patients. Among several diagnosis methods, the electrochemical sensor is the most promising one due to its outstanding performance, portability, real-time analysis, robustness, amenability, and cost-effectiveness. Conducting polymer (CP) composites have been frequently used to fabricate a robust sensor device, owing to their excellent physical and electrochemical properties as well as biocompatibility with nontoxic effects on the biological system. This review brings up a brief overview of the importance of electrochemical biosensors for the early detection of lung cancer, with a detailed discussion on the design and development of CP composite materials for biosensor applications. The review covers the electrochemical sensing of numerous lung cancer markers employing composite electrodes based on the conducting polyterthiophene, poly(3,4-ethylenedioxythiophene), polyaniline, polypyrrole, molecularly imprinted polymers, and others. In addition, a hybrid of the electrochemical biosensors and other techniques was highlighted. The outlook was also briefly discussed for the development of CP composite-based electrochemical biosensors for POC diagnostic devices.

Economic Burden of Recurrence in Completely Resected Stage IB-IIIA Non-Small Cell Lung Cancer: A Retrospective Study Using Nationwide Claims Data of South Korea.

INTRODUCTION: Although many patients with early stage non-small cell lung cancer (NSCLC) experience recurrence despite complete resection, few studies have reported on the corresponding economic burden. This study aimed to understand the economic impact of recurrence by measuring healthcare costs and resource utilization in patients with recurrent stage IB-IIIA NSCLC. METHODS: Using Health Insurance Review and Assessment claims data from South Korea, we included patients who underwent complete resection for stage IB-IIIA NSCLC during the index period (January 1, 2012, to October 31, 2018). Patients who experienced recurrence were matched with those who did not using 1:1 propensity score (PS) matching. The mean healthcare costs and resource utilization were analyzed from the date of complete resection to the last claims for cancer treatment. A generalized linear model (GLM) was used to estimate the impact of covariates on healthcare costs. A difference-in-difference (DID) analysis was conducted to analyze the healthcare costs between the two groups before and after recurrence. RESULTS: Patients with recurrence incurred higher healthcare costs, particularly in outpatient settings. The cost of targeted therapy and immune checkpoint inhibitors primarily contributed to cost differences, and medication costs increased over time after complete resection. Patients with recurrence were also hospitalized more frequently (9.3 vs. 5.0, p < 0.0001) for a longer period (74 days vs. 42 days, p < 0.0001) than those without recurrence. GLM analysis showed that the total cost was 2.31-fold higher in patients with recurrence (95% confidence interval: 2.19-2.44). The DID analysis showed significantly increased total costs in patients with recurrence (ß = 26,269, p < 0.0001), which was mostly attributed to medication costs (ß = 17,951, p < 0.0001). CONCLUSION: Recurrence of completely resected NSCLC leads to a substantial increase in healthcare costs and resource utilization. The results of this study show the economic burden of recurrence, which may help future economic analyses and resource allocation.

Electropotential-Inspired Star-Shaped Gold Nanoconfined Multiwalled Carbon Nanotubes: A Proof-of-Concept Electrosensoring Interface for Lung Metastasis Biomarkers.

Herein, an innovative way of designing a star-shaped gold nanoconfined multiwalled carbon nanotube-engineered sensoring interface (AuNS@MWCNT//GCE) is demonstrated for quantification of methionine (MTH); a proof of concept for lung metastasis. The customization of the AuNS@MWCNT is assisted by surface electrochemistry and thoroughly discussed using state-of-the-art analytical advances. Micrograph analysis proves the protrusion of nanotips on the surface of potentiostatically synthesized AuNPs and validates the hypothesis of Turkevich seed (AuNP)-mediated formation of AuNSs. In addition, a facile synthesis of electropotential-assisted transformation of MWCNTs to luminescent nitrogen-doped graphene quantum dots (Nd-GQDs avg. ∼4.3 nm) is unveiled. The sensor elucidates two dynamic responses as a function of CMTH ranging from 2 to 250 µM and from 250 to 3000 µM with a detection limit (DL) of ∼0.20 µM, and is robust to interferents except for tiny response of a similar -SH group bearing Cys (<9.00%). The high sensitivity (0.44 µA·µM-1·cm-2) and selectivity of the sensor can be attributed to the strong hybridization of the Au nanoparticle with the sp2 C atom of the MWCNTs, which makes them a powerful electron acceptor for Au-SH-MTH interaction as evidenced by density functional theory (DFT) calculations. The validation of the acceptable recovery of MTH in real serum and pharma samples by standard McCarthy-Sullivan assay reveals the holding of great promise to provide valuable information for early diagnosis as well as assessing the therapeutic consequence of lung metastasis.

Economic burden of brain metastases in non-small cell lung cancer patients in South Korea: A retrospective cohort study using nationwide claims data.

Brain metastases (BM) are common in patients with non-small cell lung cancer (NSCLC). However, the pure economic burden of BM is unknown. This study aimed to evaluate the impact of BM on healthcare costs and resource utilization in patients with NSCLC by comparing patients with and without BM. This was a retrospective cohort analysis of South Korean health insurance review and assessment claims data. Patients with stage IIIB or IV NSCLC were identified (March 1, 2013 to February 28, 2018). We compared their two-year and per-patient-per-month (PPPM) healthcare costs and resource utilization with 1:3 propensity score-matched patients without the condition. A generalized linear model was used to estimate the impact of BM and other covariates on healthcare costs. After propensity score matching with the 33 402 newly diagnosed cases of stage IIIB or IV NSCLC, 3435 and 10 305 patients were classified as having or not having BM, respectively. Mean healthcare costs were significantly greater in patients with BM for both the two years (US$ 44 692 vs. US$ 32 230, p < .0001) and PPPM (US$ 3510 vs. US$ 2573, p < .0001). The length of hospital stay was longer in patients with BM (79.15 vs. 69.41 days for two years, p < .0001; 7.69 vs. 6.86 days PPPM, p < .0001), and patients with BM had more outpatient visits (50.61 vs. 46.43 times for two years, p < .0001; 3.64 vs. 3.40 times PPPM costs, p < .0001). The costs of drugs, radiology/radiotherapy, and admission comprised the majority of PPPM costs and were higher in patients with BM. The generalized linear model analysis suggested that patients with BM had significantly increased healthcare costs (by 1.29-fold, 95% confidence interval 1.26-1.32). BM is a significant economic burden for patients with NSCLC. Therefore, it is important to prevent BM in patients with NSCLC to reduce their economic burden.

The feasibility of granzyme B levels using an amperometric immunosensor for lung cancer detection.

Background: Low-dose computed tomography (LDCT) has improved the early detection of lung cancer. However, LDCT scans present several disadvantages, including the abundance of false-positive results, which lead to a high socioeconomic cost, psychological burden, and repeated exposure to radiation. Therefore, the identification of complementary biomarkers is needed to select high-risk individuals for LDCT. Here, we showed that granzyme B testing with the novel immunosensor has diagnostic value for identifying patients with lung cancer. Methods: We enrolled 44 patients with lung cancer and 51 health controls at Pusan National University Yangsan Hospital in Korea between March 2018 and September 2019. The immunosensor analyzed serum granzyme B levels, and their association with lung cancer detection was evaluated with machine learning models. Results: Serum granzyme B levels were assessed in samples from patients with lung cancer and healthy individuals. Granzyme B testing showed 100% sensitivity, 80% specificity, and an area under the curve of 0.938 for lung cancer detection. After combining granzyme B testing with clinical predictors such as age, smoking status, or pack-years, results from the five-fold cross-validation with random forest model improved diagnostic accuracy of 92.1%, with a sensitivity, specificity, and area under the curve of 92.0%, 92.1%, and 0.977, respectively. Conclusions: This feasibility study suggested that granzyme B may be utilized to detect lung cancer.

Healthcare resource utilization and medical costs in patients with terminal cancer during best supportive care.

Patients with terminal cancer have different physical symptoms, prognoses, emotional distress, and end-of-life care plans from those receiving aggressive chemotherapy; few studies have assessed healthcare resource use in these patients. Therefore, this study aimed to assess healthcare resource utilization and medical costs incurred during best supportive care after the last anticancer drug treatment in patients with terminal cancer. This retrospective observational study was conducted using national sample cohort data from the National Health Insurance Service in South Korea. Only patients with cancer who were treated with the last anticancer drugs from January 1, 2006, to June 30, 2015, were included in the study. The period of best supportive care was defined as the time from the date of use of the last anticancer drug to death. Healthcare resource utilization and medical costs were estimated during the best supportive care. A generalized linear model with a log-link function and gamma distribution was used to evaluate the impact of demographic and healthcare utilization factors on total medical costs. Among the 2,480 patients in the study, 93.9% were hospitalized, and hospitalization days (30.8 days) accounted for 39.7% of the surviving period (77.5 days). The proportions of intensive care unit admissions and emergency department visits were 15.8% and 18.9%, respectively. The average total medical cost per patient was $6,310, with the inpatient cost ($5,705) being approximately 9.4 times higher than the outpatient cost ($605). The length of hospitalization had the greatest impact on the total medical costs. Pancreatic cancer had the highest proportion of patients who were hospitalized (97.4%) and the highest medical cost ($7,702). Hospital-based resources were utilized by most patients with terminal cancer, and hospitalization was a major driver of the total medical cost. An alternative system for hospitalization should be developed to support patients with terminal cancer, both clinically and financially.

Exosomal microRNAs array sensor with a bioconjugate composed of p53 protein and hydrazine for the specific lung cancer detection.

For the early diagnosis of lung cancer, a novel strategy to detect microRNAs encapsulated in exosomes with immunomagnetic isolation was demonstrated for the selective extraction of exo-miRNAs from patient serum. Here, miRNA was captured from lysed exosomes in specially designed capture probe modified magnetic beads, followed by T4 DNA polymerase-mediated in situ formation of chimeric 5'-miRNA-DNA-3' (Target). The poly-(2,2':5',2''-terthiophene-3'-(p-benzoic acid)) (pTBA)-modified electrode harbors Probe-1 DNA that hybridizes to the 5' end of the chimera, followed by hybridization of Probe-2 DNA to the 3' end of the chimera, resulting in the formation of a 20-nucleotide-long dsDNA consensus sequence for p53 protein binding. A bioconjugate composed of p53 and hydrazine assembled on AuNPs (p53-AuNPs-Hyd) recruits the p53 protein to recognize a specific sequence, forming the final sensor probe (pTBA-Probe-1:Target/Probe-2:bioconjugate), where hydrazine functions as an electrocatalyst to generate amperometric signal from the reduction of H2O2. This sensor has double specificity via selective capture of the target in Probe-1 and p53 recognition, which shows excellent analytical performance, revealing a dynamic range between 100 aM and 10 pM with a detection limit of 92 (±0.1) aM. For practical applications, we prepared a multiplexed array sensor to simultaneously detect four exo-miRNAs (miRNA-21, miRNA-155, miRNA-205, and miRNA-let-7b) up to femtomolar levels from 1.0 mL to 125 µL of cell culture (A549, MCF-7 and BEAS-2B) media and lung cancer patient serum samples, respectively.

Disposable amperometric immunosensor with a dual monomers-based bioconjugate for granzyme B detection in blood and cancer progress monitoring of patients.

A disposable amperometric biosensor with a dual monomers-based bioconjugate was developed for granzyme B (GzmB) detection and for monitoring of the cancer progression of patients before and after immunotherapy. The biosensor was fabricated by immobilizing a GzmB monoclonal antibody (Ab1) on a poly3'-(2-aminopyrimidyl)-2,2':5',2''-terthiophene/gold nanoparticle (pPATT/AuNP) layer. The bioconjugate nanoparticles were synthesized through self-assembly of a monomer mixture of 2,2:5,2-terthiophene-3-(p-benzoic acid) (TBA) and PATT onto AuNPs, followed by chemical binding of brilliant cresyl blue (BCB) on TBA and GzmB polyclonal antibody (Ab2) on the PATT layer. Each sensing layer was investigated by surface analysis and electrochemical experiments. The sensor performance was assessed with selectivity, stability, reproducibility, detection limit, and real sample analysis. Under the optimized conditions, the dynamic range of GzmB was in two slopes from 3.0 to 50.0 pg/ml and from 50.0 to 1000.0 pg/ml with a detection limit of 1.75 ± 0.14 pg/ml (RSD ≤5.2%). GzmB monitoring was performed for the patient's serum samples, where a low level of GzmB was observed for lung cancer patients before immunotherapy (10.51 ± 0.99 pg/ml, RSD ≤6.2%), and the level was increased after therapy (17.19 ± 2.22 pg/ml, RSD ≤2.6%). Moreover, a significantly higher level was present in healthy persons (34.40 ± 3.92 pg/ml, RSD ≤1.4%). The cancer progression of patients before and after therapy was evaluated by monitoring GzmB levels in human serum using the proposed sensor.

Nanozyme-based electrochemical biosensors for disease biomarker detection.

In recent years, a new group of nanomaterials named nanozymes that exhibit enzyme-mimicking catalytic activity has emerged as a promising alternative to natural enzymes. Nanozymes can address some of the intrinsic limitations of natural enzymes such as high cost, low stability, difficulty in storage, and specific working conditions (i.e., narrow substrate, temperature and pH ranges). Thus, synthesis and applications of hybrid and stimuli-responsive advanced nanozymes could revolutionize the current practice in life sciences and biosensor applications. On the other hand, electrochemical biosensors have long been used as an efficient way for quantitative detection of analytes (biomarkers) of interest. As such, the use of nanozymes in electrochemical biosensors is particularly important to achieve low cost and stable biosensors for prognostics, diagnostics, and therapeutic monitoring of diseases. Herein, we summarize the recent advances in the synthesis and classification of common nanozymes and their application in electrochemical biosensor development. After briefly overviewing the applications of nanozymes in non-electrochemical-based biomolecular sensing systems, we thoroughly discuss the state-of-the-art advances in nanozyme-based electrochemical biosensors, including genosensors, immunosensors, cytosensors and aptasensors. The applications of nanozymes in microfluidic-based assays are also discussed separately. We also highlight the challenges of nanozyme-based electrochemical biosensors and provide some possible strategies to address these limitations. Finally, future perspectives on the development of nanozyme-based electrochemical biosensors for disease biomarker detection are presented. We envisage that standardization of nanozymes and their fabrication process may bring a paradigm shift in biomolecular sensing by fabricating highly specific, multi-enzyme mimicking nanozymes for highly sensitive, selective, and low-biofouling electrochemical biosensors.

MicroRNAs in ovarian cancer and recent advances in the development of microRNA-based biosensors.

Ovarian cancer is the most aggressive of all gynaecological malignancies and is the leading cause of cancer-associated mortality worldwide. Over the recent years, there has been a sharp increase in this mortality rate, mostly due to late diagnosis, which can be attributed to the lack of an early and specific biomarker. Under this scenario, recent interest has shifted towards ovarian cancer associated miRNAs which play strong regulatory roles in various cellular processes. miRNAs have emerged as promising non/minimally invasive cancer biomarkers for improved diagnostic, prognostic and streamlined therapeutic applications. A large number of miRNA assays have been reported that are based on nucleic acid detection-based techniques such as RT-qPCR, microarrays and RNA sequencing methods. Despite demonstrating commendable analytical performances, these laboratory-based techniques are expensive and hence not ideally suited for routine use in resource-limited settings. In recent years, considerable attention has been dedicated to the development of relatively simple, rapid and inexpensive miRNA biosensor strategies. Among these, electrochemical sensors have shown a great promise towards point-of-care diagnostics, due to their inherent advantages such as simplicity, sensitivity, amenability to high levels of multiplexing as well as low cost. In this paper, we provide an overview of the potential role of miRNAs in ovarian cancer, as well as recent advances in the development of nanotechnology-based, optical, and electrochemical biosensing-strategies for miRNA detection.

Nano-biosensor for the in vitro lactate detection using bi-functionalized conducting polymer/N, S-doped carbon; the effect of αCHC inhibitor on lactate level in cancer cell lines.

A robust amperometric sensor was developed for the lactate detection in the extracellular matrix of cancer cells. The sensor was fabricated by separately immobilizing nicotinamide adenine dinucleotide (NAD+) onto a carboxylic acid group and lactate dehydrogenase (LDH) onto an amine group of bi-functionalized conducting polymer (poly 3-(((2,2':5',2″-terthiophen)-3'-yl)-5-aminobenzoic acid (pTTABA)) composited with N, S-doped porous carbon. Morphological features of the composite layer and sensor performance were investigated using FE-SEM, XPS, and electrochemical methods. The experimental parameters were optimized to get the best results. The calibration plot showed a linear dynamic range between 0.5 µM and 4.0 mM with the detection limit of 112 ± 0.02 nM. The proposed sensor was applied to detect lactate in a non-cancerous (Vero) and two cancer (MCF-7 and HeLa) cell lines. Among these cell lines, MCF-7 was mostly affected by the administration of lactate transport inhibitor, α-cyano-4-hydroxycinnamate (αCHC), followed by HeLa and Vero, respectively. Furthermore, the effect of αCHC concentration and treatment time on the lactate level in the cell lines were demonstrated. Finally, cytotoxicity studies were also performed to evaluate the effect of αCHC on cell viability.

Separation detection of different circulating tumor cells in the blood using an electrochemical microfluidic channel modified with a lipid-bonded conducting polymer.

Different circulating tumor cells (CTCs) in blood were separated and detected through the decoration of anti-cancer drug on the target cells, along with chemical modification of the microfluidic channel walls using a lipid attached covalently to the conducting polymer. The working principle of the electrochemical microfluidic device was evaluated with experimental parameters affecting on the separation, in terms of mass and surface charge of target species, fluid flow rate, AC amplitude, and AC frequency. The separated CTCs were selectively detected via the oxidation of daunomycin adsorbed specifically at the cells using an electrochemical sensor installed at the channel end. The fluorescence microscopic examination also confirmed the separation of CTCs in the channel. To evaluate the reliability of the method, blood samples from 37 cancer patients were tested. The device was able to separate the CTCs with 92.0 ±â€¯0.5 % efficiency and 90.9% detection rate.

Simultaneous detection of ATP metabolites in human plasma and urine based on palladium nanoparticle and poly(bromocresol green) composite sensor.

A sensitive voltammetric sensor based on palladium nanoparticles (PdNPs) and poly-bromocresol green (pBG) composite layer immobilized on amide functionalized single-walled carbon nanotubes (AmSWCNTs) modified pyrolytic graphite (PdNPs:pBG/AmSWCNTs/PG) has been prepared for the simultaneous determination of adenosine triphosphate (ATP) catabolites, inosine (INO), hypoxanthine (HX), xanthine (XT), and uric acid (UA). The modified PdNPs:pBG/AmSWCNTs/PG was characterized by electrochemical experiments and surface analysis, which exhibited exceptional electrocatalytic effects towards the oxidation of INO, HX, XT, and UA with a significant enhanced peak current and well resolved peaks separation for all the analytes. The linear calibration curves were obtained in the concentration range of 0.001-175 µM, 0.001-200 µM, 0.001-150 µM, and 0.001-200 µM and limits of detection were found as 0.95 nM, 1.04 nM, 1.07 nM, and 0.43 nM corresponding to INO, HX, XT, and UA, respectively. The common metabolites present in the biological fluids did not interfere in the determination. The applicability of the proposed sensor was successfully demonstrated by determining INO, HX, XT, and UA in the human plasma and urine and the obtained results were validated by using HPLC.

Ultrasensitive dual probe immunosensor for the monitoring of nicotine induced-brain derived neurotrophic factor released from cancer cells.

Brain-derived neurotrophic factor (BDNF) was detected in the extracellular matrix of neuronal cells using a dual probe immunosensor (DPI), where one of them was used as a working and another bioconjugate loading probe. The working probe was fabricated by covalently immobilizing capture anti-BDNF (Cap Ab) on the gold nanoparticles (AuNPs)/conducting polymer composite layer. The bioconjugate probe was modified by drop casting a bioconjugate particles composed of conducting polymer self-assembled AuNPs, immobilized with detection anti-BDNF (Det Ab) and toluidine blue O (TBO). Each sensor layer was characterized using the surface analysis and electrochemical methods. Two modified probes were precisely faced each other to form a microfluidic channel structure and the gap between inside modified surfaces was about 19 µm. At optimized conditions, the DPI showed a linear dynamic range from 4.0 to 600.0 pg/ml with a detection limit of 1.5 ±â€¯0.012 pg/ml. Interference effect of IgG, arginine, glutamine, serine, albumin, and fibrinogene were examined and stability of the developed biosensor was also investigated. The reliability of the DPI sensor was evaluated by monitoring the extracellular release of BDNF using exogenic activators (ethanol, K+, and nicotine) in neuronal and non-neuronal cells. In addition, the effect of nicotine onto neuroblastoma cancer cells (SH-SY5Y) was studied in detail.

Performance comparison between multienzymes loaded single and dual electrodes for the simultaneous electrochemical detection of adenosine and metabolites in cancerous cells.

The analytical performance of the multi enzymes loaded single electrode sensor (SES) and dual electrode sensor (DES) was compared for the detection of adenosine and metabolites. The SES was fabricated by covalent binding of tri-enzymes, adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), and xanthine oxidase (XO) along with hydrazine (Hyd) onto a functionalized conducting polymer [2,2:5,2-terthiophene-3-(p-benzoic acid)] (pTTBA). The enzyme reaction electrode in DES was fabricated by covalent binding of ADA and PNP onto pTTBA coated on Au nanoparticles. The detection electrode in DES was constructed by covalent binding of XO and Hyd onto pTTBA coated on porous Au. Due to the higher amount (3.5 folds) of the immobilized enzymes and Hyd onto the DES than SES, and the lower Michaelis constant (Km) value for DES (28.7 µM) compared to SES (36.1 µM), the sensitivity was significantly enhanced for the DES (8.2 folds). The dynamic range obtained using DES was from 0.5 nM to 120.0 µM with a detection limit of 1.43 nM ±â€¯0.02, 0.76 nM ±â€¯0.02, and 0.48 nM ±â€¯0.01, for adenosine (AD), inosine (IN), and hypoxanthine (Hypo) respectively. Further, the DES was coupled with an electrochemical potential modulated microchannel for the separation and simultaneous detection of AD, IN, and Hypo in an extracellular matrix of cancerous (A549) and non-cancerous (Vero) cells. The sensor probe confirms a higher basal level of extracellular AD and its metabolites in cancer cells compared to normal cells. In addition, the effect of dipyridamole on released adenosine in A549 cells was investigated.

A selective glucose sensor based on direct oxidation on a bimetal catalyst with a molecular imprinted polymer.

A selective nonenzymatic glucose sensor was developed based on the direct oxidation of glucose on hierarchical CuCo bimetal-coated with a glucose-imprinted polymer (GIP). Glucose was introduced into the GIP composed of Nafion and polyurethane along with aminophenyl boronic acid (APBA), which was formed on the bimetal electrode formed on a screen-printed electrode. The extraction of glucose from the GIP allowed for the selective permeation of glucose into the bimetal electrode surface for oxidation. The GIP-coated bimetal sensor probe was characterized using electrochemical and surface analytical methods. The GIP layer coated on the NaOH pre-treated bimetal electrode exhibited a dynamic range between 1.0µM and 25.0mM with a detection limit of 0.65±0.10µM in phosphate buffer solution (pH 7.4). The anodic responses of uric acid, acetaminophen, dopamine, ascorbic acid, L-cysteine, and other saccharides (monosaccharides: galactose, mannose, fructose, and xylose; disaccharides: sucrose, lactose, and maltose) were not detected using the GIP-coated bimetal sensor. The reliability of the sensor was evaluated by the determination of glucose in artificial and whole blood samples.

Development of a bifunctional nanobiosensor for screening and detection of chemokine ligand in colorectal cancer cell line.

Highly sensitive detection of chemokines in various biological matrices and its interaction with a natural receptor molecule has tremendous importance in cell signaling, medical diagnostics, and therapeutics. In this direction, we have designed the first bifunctional nanobiosensor for chemokine screening and detection in a single experimental setting. The sensor probe was fabricated by immobilizing CXCR2 on the gold nanoparticles (AuNPs) deposited 2,2':5',2''-terthiophene-3' (p-benzoic acid) (TBA) nanocomposite film. The interaction between CXCR2 and chemokines was studied using electrochemical impedance spectroscopy (EIS) and voltammetry. CXCL5 among three ligands showed the strongest affinity to CXCR2, which was further utilized to develop an amperometric CXCL5 biosensor. Analytical parameters, such as CXCR2 receptor concentration, temperature, pH, and incubation time were optimized to obtain the high sensitivity. A dynamic range for CXCL5 detection was obtained between 0.1 and 10ng/mL with the detection limit of 0.078 ± 0.004ng/mL (RSD < 4.7%). The proposed biosensor was successfully applied to detect CXCL5 in clinically relevant concentrations in human serum and colorectal cancer cells samples with high sensitivity and selectivity. Interference effect and the stability of the developed biosensor were also evaluated. Method verification was performed by comparing the results using commercially available ELISA kit for CXCL5 detection.

Detection of Ca2+-induced acetylcholine released from leukemic T-cells using an amperometric microfluidic sensor.

A microfluidic structured-dual electrodes sensor comprising of a pair of screen printed carbon electrodes was fabricated to detect acetylcholine, where one of them was used for an enzyme reaction and another for a detection electrode. The former was coated with gold nanoparticles and the latter with a porous gold layer, followed by electropolymerization of 2, 2:5,2-terthiophene-3-(p-benzoic acid) (pTTBA) on both the electrodes. Then, acetylcholinesterase was covalently attached onto the reaction electrode, and hydrazine and choline oxidase were co-immobilized on the detection electrode. The layers of both modified electrodes were characterized employing voltammetry, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and quartz crystal microscopy. After the modifications of both electrode surfaces, they were precisely faced each other to form a microfluidic channel structure, where H2O2 produced from the sequential enzymatic reactions was reduced by hydrazine to obtain the analytical signal which was analyzed by the detection electrode. The microfluidic sensor at the optimized experimental conditions exhibited a wide dynamic range from 0.7nM to 1500µM with the detection limit of 0.6 ± 0.1nM based on 3s (S/N = 3). The biomedical application of the proposed sensor was evaluated by detecting acetylcholine in human plasma samples. Moreover, the Ca2+-induced acetylcholine released in leukemic T-cells was also investigated to show the in vitro detection ability of the designed microfluidic sensor. Interference due to the real component matrix were also studied and long term stability of the designed sensor was evaluated. The analytical performance of the designed sensor was also compared with commercially available ACh detection kit.