Detection Of Theophylline Research Articles

Gadolinium oxide modified molecular imprinted polymer electrode for the electrochemical detection of theophylline in black tea

The present study reported a facile approach to fabricate a molecular imprinted polymer electrode modified with nano-composites of gadolinium oxide (Gd2O3@TH-MIP-CPE) to detect theophylline in variants of black tea samples. The synthesized electrode material was characterized by scanning electron microscope, fourier transform infrared spectroscopy and UV–visible spectroscopy. The electroanalytic performance of the Gd2O3@TH-MIP-CPE electrode was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The electrode exhibits a linear response from 50 µM to 900 µM with limit of detection being 2.004 µM. The electrode showed significant repeatability (%RSD=1.19), reproducibility (%RSD=0.92) and stability (%RSD=1.015). To evaluate the predictive ability of the electrode, partial least square regression (PLSR) model has been developed by correlating the high-performance liquid chromatography (HPLC) values with the voltammogram signals recorded using the electrode. The average prediction accuracy obtained from the PLSR model is 91.3 % with root mean square error of calibration being as low as 0.73.

A BDD-Au/SPCE-based electrochemical DNA aptasensor for selective and sensitive detection of theophylline

The proposed aptasensor using a DNA aptamer for the detection of theophylline (THEO) is being reported for the first time, as previous methods predominantly employed RNA aptamers. DNA aptamers have attracted significant attention due to their advantages over antibodies, including greater stability and cost-effectiveness, making them ideal for various diagnostic applications as biosensors. THEO, a drug commonly used in the treatment of respiratory diseases such as asthma, requires precise monitoring in the bloodstream due to its narrow therapeutic index. In this paper, we present the first optimization of THEO detection using a DNA aptamer-based sensor (aptasensor), utilizing a composite boron-doped diamond/Gold (BDD-Au) on screen-printed carbon electrodes. Thiolated DNA aptamers were immobilized on the BDD-Au surface, where they selectively targeted THEO in biological samples. Optimization of the aptasensor was achieved using a Box-Behnken design, determining optimal conditions of 3.0 μM for aptamer concentration, 90 min for aptamer immobilization time, and 1.0 mM for tris(2-carboxyethyl)phosphine concentration. The resulting DNA aptasensor demonstrated excellent selectivity for THEO, with a linear detection range from 1 to 1.0 mM and a detection limit of 52 nM. The sensor maintained stability for up to four weeks and exhibited high recovery rates when tested in blood serum, highlighting its potential for clinical monitoring of THEO levels.

Sensitive Detection of Theophylline Using a Modified Glassy Carbon Electrode with g-C3N4

Sensitive Detection of Theophylline Using a Modified Glassy Carbon Electrode with g-C3N4

Highly sensitive detection of theophylline by differential pulse voltammetry using zinc oxide nanoparticles and multiwalled carbon nanotubes-modified carbon paste electrode

Highly sensitive detection of theophylline by differential pulse voltammetry using zinc oxide nanoparticles and multiwalled carbon nanotubes-modified carbon paste electrode

A miniaturized additive-manufactured carbon black/PLA electrochemical sensor for pharmaceuticals detection

Additive manufacturing is a technique that allows the construction of prototypes and has evolved a lot in the last 20 years, innovating industrial fabrication processes in several areas. In chemistry, additive manufacturing has been used in several functionalities, such as microfluidic analytical devices, energy storage devices, and electrochemical sensors. Theophylline and paracetamol are important pharmaceutical drugs where overdosing can cause adverse effects, such as tachycardia, seizures, and even renal failure. Therefore, this paper aims at the development of miniaturized electrochemical sensors using 3D printing and polylactic acid-based conductive carbon black commercial filament for theophylline and paracetamol detection. Electrochemical characterizations of the proposed sensor were performed to prove the functionality of the device. Morphological characterizations were carried out, in which chemical treatment could change the surface structure, causing the improvement of the analytical signal. Thus, the detection of theophylline at a linear range of 5.00–150 μmol L−1 with a limit of detection of 1.2 μmol L−1 was attained, and the detection of paracetamol at a linear range of 1.00–200 μmol L−1 with a limit of detection of 0.370 μmol L−1 was obtained, demonstrating the proposed sensor effectively detected pharmaceutical drugs.

Graphitic carbon nitride supported Gd(OH)3/CuO nano-rods: A high-performance catalyst for electro-catalytic theophylline detection

BackgroundMonitoring the drug components is important to maintain the patient's health. Theophylline (THE) is a drug used to treat asthma, which has serious health consequences if consumed in excess. This drug is also found in food, so the chance of increased consumption must be high. In addition, low levels of medication lead to improper treatment. Therefore, monitoring this type of medication is a crucial factor. MethodsSynthesis of an efficient electrocatalyst, combining gadolinium copper oxide with graphitic carbon nitride (GCO-gCN) via facile hydrothermal method. Physical characterizations validated the GCO-gCN composites, prepared well and highly interconnected. Determining THE through analyzing current responses from GCO-gCN/GCE using cyclic voltammetry (CV), and differential pulse voltammetry (DPV) as an electrochemical sensor. The developed technique was effectively applied to determine THE in food and serum samples, yielding satisfactory outcomes. Significant findingsDetection parameters such as limit of detection (LOD = 9.6 ng/L), sensitivity (0.716 μA/μM cm²), and limit of quantification (LOQ = 29.32 ng/L), were successfully determined. Additionally, the sensors exhibited exceptional interference resistance, high sensitivity, robust stability, and reliable repeatability and reproducibility (RSD < 5 %). This study underscores the GCO-gCN/GCE composite's potential as a highly efficient material for sensitive and reliable THE detection.

A novel fluorescent aptasensor for the detection of theophylline based on cryonase-driven signal amplification strategy.

In the study, we have developed an expedient and efficient method for the detection of theophylline based on the amplification of the signal intensity of fluorescence based on oxidized single-walled carbon nanohorns (oxSWCNHs)/cryonase. When theophylline was not present in the system, oxSWCNHs can adequately adsorb nucleic acid probes labeled by carboxyfluorescein (FAM). In the presence of theophylline, the nucleic acid probe forms the tertiary probe-theophylline complex, which detaches from the surface of the oxSWCNHs. Then, upon reaction with cryonase, the complex can release the FAM and theophylline into the next cycle. The fluorescence signal of the system exhibits a 1:N magnification, enabling quantitative detection of theophylline. The linear range was 30-150 ng/mL, and the limit of detection (LOD) was 6.04 ng/mL. At the same time, it can also be used to detect theophylline in mouse serum.

Lanthanum vanadate-based carbon nanocomposite as an electrochemical probe for amperometric detection of theophylline in real food samples.

Theophylline (THP) is an emerging drug for chronic obstructive pulmonary disease whose side effects can be greatly affected by caffeine-containing real foods. Because an overdose of this substance can cause respiratory and neurological damage, producing a fast and accurate analytical procedure is critical. Based on a cutting-edge hybrid nanocomposite, this study was used to construct an electrochemical sensor for the accurate detection of THP. Spectroscopy and morphological investigation supported the easy synthesis of tetragonal-LaVO4 (t-LV) nanopellets and LV@CNF hybrid nanocomposite. To detect THP, a highly dispersed LV@CNF nanocomposite was modified on a glassy carbon electrode as a sensing substrate. By amperometric technique, the sensor shows a wide linear range of 0.01-1070μM, low limit of detection (2.63nM), and sensitivity (0.228 μA μM-1 cm-2). Finally, the current technique was successfully used to identify THP in real food samples (chocolate, coffee and black tea).

Genetically Encoded RNA Sensors for Ratiometric and Multiplexed Imaging of Small Molecules in Living Cells.

Genetically encoded sensors afford powerful tools for studying small molecules and metabolites in live cells. However, genetically encoded sensors with a general design remain to be developed. Here we develop genetically encoded RNA sensors with a modular design for ratiometric and multiplexed imaging of small molecules in live cells. The sensor utilizes aptazyme as a recognition module and the light-up RNA aptamer as a signal reporter. The conformation of light-up aptamers is abrogated by a blocking sequence, and aptazyme-mediated cleavage restores the correct conformation, delivering activated fluorescence for small molecule imaging. We first developed a genetically encoded ratiometric sensor using Mango aptamer as a reference and SRB2 as a reporter. It is shown that the sensor allows quantitative imaging and detection of theophylline in live cells. The generality of the design is further demonstrated for imaging other small molecules by replacing the aptazymes. Its ability for multiplexed imaging of small molecules is further explored via the integration of different small-molecule responsive aptazymes and light-up RNA aptamers. This modular design could offer a versatile platform for imaging diverse molecules in living cells.

Bio-SCAN V2: A CRISPR/dCas9-based lateral flow assay for rapid detection of theophylline.

Rapid, specific, and robust diagnostic strategies are needed to develop sensitive biosensors for small molecule detection, which could aid in controlling contamination and disease transmission. Recently, the target-induced collateral activity of Cas nucleases [clustered regularly interspaced short palindromic repeats (CRISPR)-associated nucleases] was exploited to develop high-throughput diagnostic modules for detecting nucleic acids and small molecules. Here, we have expanded the diagnostic ability of the CRISPR-Cas system by developing Bio-SCAN V2, a ligand-responsive CRISPR-Cas platform for detecting non-nucleic acid small molecule targets. The Bio-SCAN V2 consists of an engineered ligand-responsive sgRNA (ligRNA), biotinylated dead Cas9 (dCas9-biotin), 6-carboxyfluorescein (FAM)-labeled amplicons, and lateral flow assay (LFA) strips. LigRNA interacts with dCas9-biotin only in the presence of sgRNA-specific ligand molecules to make a ribonucleoprotein (RNP). Next, the ligand-induced ribonucleoprotein is exposed to FAM-labeled amplicons for binding, and the presence of the ligand (small molecule) is detected as a visual signal [(dCas9-biotin)-ligRNA-FAM labeled DNA-AuNP complex] at the test line of the lateral flow assay strip. With the Bio-SCAN V2 platform, we are able to detect the model molecule theophylline with a limit of detection (LOD) up to 2μM in a short time, requiring only 15min from sample application to visual readout. Taken together, Bio-SCAN V2 assay provides a rapid, specific, and ultrasensitive detection platform for theophylline.

An Electrochemical Electrode to Detect Theophylline Based on Copper Oxide Nanoparticles Composited with Graphene Oxide.

The electrochemical analysis of theophylline (THP) was investigated by fabricating a carbon paste electrode (CPE) modified with graphene oxide (GO) along with copper oxide (CuO) nanoparticles (CuO-GO/CPE). The impact of electro-kinetic parameters such as the heterogeneous rate constant, the scan rate, the accumulation time, the pH, the transfer coefficient, and the number of electrons and protons transferred into the electro-oxidation mechanism of THP has been studied utilizing electrochemical methods such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The differential pulse voltammetry technique was employed to investigate THP in pharmaceutical and biological samples, confirming the limit of detection (LOD) and quantification (LOQ) of the THP. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were performed to characterize the CuO nanoparticles. The CuO-GO/CPE was more sensitive in THP detection because its electrocatalytic characteristics displayed an enhanced peak current in the 0.2 M supporting electrolyte of pH 6.0, proving the excellent sensing functioning of the modified electrode.

A sensing platform based on zinc-porphyrin derinative in hexadecyl trimethyl ammonium bromide (CTAB) microemulsion for highly sensitive detection of theophylline

A new porphyrin-based sensing platform in hexadecyl trimethyl ammonium bromide (CTAB) microemulsion is developed for highly sensitive detection of theophylline. In this sensing system, the zinc-porphyrin-cinnamic acid conjugate (Zn-TPPCA) works as fluorescence probe while theophylline can decrease fluorescence intensity of the probe. Further studies indicate the linear relationship between the fluorescence quenching value and the concentration of theophylline within a given range. And the introduction of CTAB microemulsion can greatly enhance sensibility and stability of this detecting system and facilitate the detection of theophylline. On the basis above, a highly sensitive sensing platform for theophylline is created with a low limit of detection (LOD) of 0.0083 μg mL−1 under the optimal detection conditions. And further application of this method in determination of commercially available theophylline preparation shows excellent results. Subsequent studies on quenching mechanism indicate that static quenching appears between Zn-TPPCA and theophylline. Therefore, this work provides not only a highly sensitive method for determination of theophylline but also further evidence for creation of biosensors for drugs with porphyrin derivatives.

Ultra-trace detection of caffeine and theophylline with high sensitivity and selectivity using Gd2(MoO4)3 nanosheets

In this study, gadolinium molybdate, Gd2(MoO4)3 (Gam) nanosheets have been substantially synthesized using a hydrothermal method with varying reaction temperatures. PXRD, XPS, and HR-TEM confirmed the crystal phase and morphology of Gam nanosheets. According to CV, LSV, and EIS techniques, Gam (synthesized at 150 ℃) modified GCE possesses excellent electrochemical properties and further has been used for caffeine and theophylline detection. The limit of detection of caffeine was found to be 4.1 nM with a linear range of 0.01 – 0.1 μM and 0.2 – 1.6 μM. Limit of detection of theophylline was calculated to be 11.9 nM with a linear range of 0.03 – 1.5 μM and 2.0 – 4.5 μM. Gam modified GCE was applied for caffeine and theophylline detection in green tea leaves (GS-1) and coca (CS-2) samples and interestingly found capable for caffeine detection without spiking. After spiking, recoveries of caffeine and theophylline in GS-1 were achieved 100.6 – 101.7% and 102.57–105.21% respectively. In CS-2 the recoveries for caffeine and theophylline were found to be 98.3 – 101.8% and 97 – 99.33% respectively. The excellent long-term stability, recyclability, and real sample analysis validated the sensor for biological as well as pharmaceutical samples diagnosis.

Electrochemical Sensor Based on CuO Nanoparticles Fabricated From Copper Wire Recycling-loaded Carbon Paste Electrode for Excellent Detection of Theophylline in Pharmaceutical Formulations

Electrochemical Sensor Based on CuO Nanoparticles Fabricated From Copper Wire Recycling-loaded Carbon Paste Electrode for Excellent Detection of Theophylline in Pharmaceutical Formulations

Rapid and Sensitive Quantification of Isoproterenol in the Presence of Theophylline by CuO Nanoflowers Modified Electrochemical Sensor

Isoproterenol is an important catecholamine-based drug that is widely used in the treatment of heart disease. The present paper introduced one of the new modifications for the surfaces of glassy carbon electrodes (GCEs) using the CuO nanoflowers (CuO NFs) for determination of isoproterenol. Electrochemical properties of the CuO NFs/GCE for detecting isoproterenol were tested using the cyclic voltammetry (CV), chronoamperometry (CHA) as well as differential pulse voltammetry (DPV). Electrochemical studies demonstrated an efficient isoproterenol oxidation, with enhanced peak current from 2.9 µA to about 10.0 µA (3.4% increase) and decreased peak potential from 500 mV to about 300 mV. The linear response for the determination of isoproterenol was obtained in ranges for concentrations between 0.3 and 450.0 μM under the most proper conditions and the limit of detection (LOD) equaled 0.09 μM. Also, the modified electrode is utilized for simultaneously determining isoproterenol and theophylline using DPV. The proposed CuO NFs/GCE sensor was effectively employed for the isoproterenol and theophylline detection in the isoproterenol ampoule and urine samples.

High-performance catalytic strips assembled with BiOBr Nano-rose architectures for electrochemical and SERS detection of theophylline

The recent developments in the healthcare sector and administration of various drugs into human systems demands for ultra-sensitive detection of drugs. Theophylline (TP) is one such drug extensively consumed for numerous respiratory disorders. In order to avoid the side effects caused by TP, consistent monitoring of it is of prime importance. Here, we developed a multifunctional screen-printed carbon electrode (SPCE) based catalytic strips loaded with BiOBr nano rose (BOB-NR) like architectures. The SPCE catalytic strips are exploited for dual mode (electrochemical and surface enhanced Raman spectroscopy (SERS)) detection of toxic drug TP. The hydrothermally prepared BiOBr nanostructures are thoroughly characterized for its physical properties and attached to SPCE through a unique gravity offered drying (GOD) strategy. The BOB-NR offered less charge transfer resistance and diffusion resistance upon the electrochemical investigation indicating its superior electrocatalytic capabilities. It reflected on projecting a wide linear range and excellent limit of detection (LOD) for electrochemical detection of TP. On the other side, the plasmonic Au layer deposited on the BOB-NR loaded SPCE strips (BiOBr/Au@SPCE) are employed for rapid SERS detection of TP. The higher enhancement factor of 107 is obtained for BiOBr/Au@SPCE strips for TP detection owing to its catalytic activity between Au layer and BiOBr nanostructures. The Au layer aids in developing a localized electromagnetic hotspot and the charge transfer process arising from BiOBr to Au all together plays a critical role in achieving a superior SERS performance. The fabricated multifunctional catalytic strips are also tested for its stability, repeatability and real-world analysis. Our established platform for detection of toxic drugs promises to be greater prospect for portable, rapid and on the spot analysis.

A malachite green light-up aptasensor for the detection of theophylline

Biosensors are of interest for the quantitative detection of small molecules (metabolites, drugs and contaminants for instance). To this end, fluorescence is a widely used technique that is easily associated to aptamers. Light-up aptamers constitute a particular class of oligonucleotides that, specifically induce fluorescence emission when binding to cognate fluorogenic ligands such as malachite green (MG). We engineered a dual aptasensor for theophylline (Th) based on the combination of switching hairpin aptamers specific for MG on the one hand and for Th on the other hand, hence their names: malaswitch (Msw) and theoswitch (Thsw). The two aptaswitches form a loop-loop or kissing Msw-Thsw complex only in the presence of theophylline, allowing binding of MG, subsequently generating a fluorescent signal. The combination of the best Msw and Thsw variants, MswG12 and Thsw19.1, results in a 20-fold fluorescence enhancement of MG at saturating theophylline concentration. This aptasensor discriminates between theophylline and its analogues caffeine and theobromine. Kissing aptaswitches derived from light-up aptamers constitute a novel sensing device.

Fabrication of poly-sulfosalicylic acid film decorated pure carbon fiber as electrochemical sensing platform for detection of theophylline

In this work, we integrated the superiority of good conductivity, large surface area of carbon fibers and the catalytic property, good biocompatibility of polymer sulfosalicylic acid to construct a novel electrochemical sensor to detect theophylline in drug analysis. The morphology of nanocomposite was characterized by scanning electron microscopy (SEM). The polymerization between monomers was observed by Fourier transform infrared spectroscopy (FTIR). The composite between carbon material and polymer was verified by Raman spectrum. Under the optimal experimental conditions, the concentration of theophylline (0.6∼137 μM) and the peak current value revealed a good linear relationship and the limit of detection as low as 0.2 μM. In addition, the proposed sensor exhibits repeatability, stability and ease of selectivity.

A split aptamer sensing platform for highly sensitive detection of theophylline based on dual-color fluorescence colocalization and single molecule photobleaching

A new split aptamer sensing platform is developed for highly sensitive and selective detection of theophylline based on single molecule photobleaching (SMPB) technique. The sensing system contains two probes. One is formed by one streptavidin and four biotinylated RNA fragments labelled with fluorescein isothiocyanate (FITC). Each biotinylated RNA fragment contains two repeating aptamer fragments. The other probe is the complementary aptamer fragment labelled with Cy5 dye. The existence of theophylline can trigger the first probe to bind as many as eight Cy5-labelled probes. The average combined number depends on the theophylline concentration and can be measured by SMPB technique. In the sensing system, the dual-color fluorescence colocalization is performed by the red fluorophore (Cy5) and green fluorophore (FITC), in which the red fluorophore is utilized for quantitative counting of photobleaching steps, while the green fluorophore serves as a counting reference to increase detection efficiency. On basis of the principle, an ultra-sensitive sensing platform of theophylline is created with a low limit of detection (LOD) of 0.092 nM. This work provides not only a highly sensitive method for theophylline detection but also a novel perspective for the applications of SMPB technology to construct biosensors.

Identifying conformational changes of aptamer binding to theophylline: A combined biolayer interferometry, surface-enhanced Raman spectroscopy, and molecular dynamics study

Theophylline is a potent bronchodilator for the treatment of asthma, bronchitis, and emphysema. Its narrow therapeutic window (20–100 μM) demands that the blood concentration of theophylline be monitored carefully, which can be achieved by aptamer capture. Thus, an understanding of what occurs when aptamers bind to theophylline is critical for identifying a high-affinity and high-specificity aptamer, which improve the sensitivity and selectivity of theophylline detection. Consequently, there is an urgent need to develop a simple, convenient, and nondestructive method to monitor conformational changes during the binding process. Here, we report the determination of the affinity of a selected aptamer and theophylline via biolayer interferometry (BLI) experiments. Additionally, using surface-enhanced Raman spectroscopy (SERS), the conformational changes on theophylline–aptamer binding were identified from differences in the SER spectra. Finally, molecular dynamics (MD) simulations were used to identify the specific conformational changes of the aptamer during the binding process. Such a combined BLI-SERS-MD method provides an in-depth understanding of the theophylline–aptamer binding processes and a comprehensive explanation for conformational changes, which helps to select, design, and modify an aptamer with high affinity and specificity. It can also be used as a scheme for the study of other aptamer–ligand interactions, which can be applied to the detection, sensing, clinical diagnosis, and treatment of diseases.