Nonhydrolytic sol–gel derived imprinted polymer–multiwalled carbon nanotubes composite fiber sensors for electrochemical sensing of uracil and 5-fluorouracil

Rapid determination of uracil in biological fluids at mercury thin film electrode for early detection of potential 5-fluorouracil toxicity due to dihydropyrimidine dehydrogenase deficiency

Determination of plasma uracil was reported as a method for evaluation of Dihydropyrimidine dehydrogenase (DPD) activity that is highly demanded to ensure the safe administration of 5-fluorouracil (5-FU)-based therapies to cancer patients. This work reports the development of a simple electroanalytical method based on adsorptive stripping square wave voltammetry (AdSWV) at mercury film-coated glassy carbon electrode (MF/GCE) for the highly sensitive determination of uracil in biological fluids that can be used for diagnosis of decreased DPD activity. Due to the formation of the HgII-Uracil complex at the electrode surface, the accuracy of the measurement was not affected by the complicated matrices in biological fluids including human serum, plasma, and urine. The high sensitivity of the developed method results in a low limit of detection (≈1.3 nM) in human plasma samples, falling below the practical cut-off level of 15 ng mL-1 (≈0.14 μM). This threshold concentration is crucial for predicting 5-FU toxicity, as reported in buffer, and ≤1.15% in biological samples), and accuracy (recovery percentage close to 100%).

Electrochemistry as a Powerful Tool for Investigations of Antineoplastic Agents: A Comprehensive Review

Cancer is most frequently treated with antineoplastic agents (ANAs) that are hazardous to patients undergoing chemotherapy and the healthcare workers who handle ANAs in the course of their duties. All aspects related to hazardous oncological drugs illustrate that the monitoring of ANAs is essential to minimize the risks associated with these drugs. Among all analytical techniques used to test ANAs, electrochemistry holds an important position. This review, for the first time, comprehensively describes the progress done in electrochemistry of ANAs by means of a variety of bare or modified (bio)sensors over the last four decades (in the period of 1982-2021). Attention is paid not only to the development of electrochemical sensing protocols of ANAs in various biological, environmental, and pharmaceutical matrices but also to achievements of electrochemical techniques in the examination of the interactions of ANAs with deoxyribonucleic acid (DNA), carcinogenic cells, biomimetic membranes, peptides, and enzymes. Other aspects, including the enantiopurity studies, differentiation between single-stranded and double-stranded DNA without using any label or tag, studies on ANAs degradation, and their pharmacokinetics, by means of electrochemical techniques are also commented. Finally, concluding remarks that underline the existence of a significant niche for the basic electrochemical research that should be filled in the future are presented.

An updated review on properties, nanodelivery systems, and analytical methods for the determination of 5-fluorouracil in pharmaceutical and biological samples

Abstract:

5-Fluorouracil (5-FU) is an antimetabolite drug used for over 70 years as first-line chemotherapy to treat various types of cancer, such as head, neck, breast and colorectal cancer. 5-FU acts mainly by inhibiting thymidylate synthase, thereby interfering with deoxyribonucleic acid (DNA) replication or by 5-FU incorporating into DNA, causing damage to the sequence of nucleotides. Being analogous to uracil, 5-FU enters cells using the same transport mechanism, where a is converted into active metabolites such as fluorouridine triphosphate (FUTP), fluorodeoxyuridine monophosphate (FdUMP), and fluorodeoxyuridine triphosphate (FdUTP). Currently, there are several nanodelivery systems being developed and evaluated at the preclinical level to overcome existing limitations to 5-FU chemotherapy, including liposomes, polymeric nanoparticles, polymeric micelles, nanoemulsions, mesoporous silica nanoparticles, and solid lipid nanoparticles. Therefore, it is essential to choose and develop suitable analytical methods for the quantification of 5-FU and its metabolites (5-fluorouridine and 5-fluoro-2-deoxyuridine) in pharmaceutical and biological samples. Among the analytical techniques, chromatographic methods are commonly the most used for the quantification of 5-FU from different matrices. However, other analytical methods have also been developed for the determination of 5-FU, such as electrochemical methods, a sensitive, selective, and precise technique, in addition to having a reduced cost. Here, we first review the physicochemical properties, mechanism of action, and advances in 5-FU nanodelivery systems. Next, we summarize the current progress of other chromatographic methods described to determine 5-FU. Lastly, we discuss the advantages of electrochemical methods for the identification and quantification of 5-FU and its metabolites in pharmaceutical and biological samples.

Fabricating Nanosheets and Ratiometric Detection of 5-Fluorouracil by Covalent Organic Framework Hybrid Material

Covalent organic framework (COF) nanosheets (NSs) are a new member in the family of two-dimensional (2D) nanomaterials that received increasing attention. The ability to prepare COF NSs with rapid acquisition is of great importance to explore their distinctive properties and potential applications. Herein, we elaborate design a new COF hybrid material EB-TFP:Eu(BTA)₄ as a sensing platform. In the process of ratiometric fluorescence detection of 5-fluorouracil (5FU), an anticancer drug, we realize the preparation of COF NSs. Interaction occurs between 5FU and COF hybrid material, where the interlayer π-π stacking of COF was weakened, benefiting the exfoliation of bulk COF to acquire 2D COF NSs. This strategy provides not only a sensitive and selective 5FU sensor but also a significant inspiration for engineering 2D COF NSs.

Porphyran-capped silver nanoparticles as a promising antibacterial agent and electrode modifier for 5-fluorouracil electroanalysis

In the present work, the green synthesis of silver nanoparticles (AgNPs) using the sulfated polysaccharide porphyran (PFR) as capping agent and d-glucose as reducing agent is described. PFR was extracted from red seaweed and characterized by employing ¹³C NMR and determination of total sugar, protein, and sulfate contents. The obtained AgNPs-PFR were characterized by using UV-VIS spectroscopy, zeta potential determination, FESEM, and TEM, which demonstrated that PFR was effective at capping the AgNPs, yielding stable suspensions. The AgNPs-PFR presented good antimicrobial properties against Gram-positive and Gram-negative bacterial strains (Staphylococcus aureus and Escherichia coli, respectively). The AgNPs-PFR were also employed as the modifier of carbon paste electrodes, which were efficiently applied as electrochemical sensors for the determination of 5-fluorouracil (5-FU), an important anticancer drug, through square wave voltammetry (SWV). The AgNPs-PFR improved the electrochemical properties of the electrodes, and enhanced their electroanalytical performance. The developed sensing device presented detection and quantification limits equal to 10.7 and 35.8 μmol L-1, respectively, towards 5-FU determination. The proposed electrochemical sensor successfully quantified 5-FU in a real pharmaceutical formulation, confirming its potential as a new promising analytical detection tool for 5-FU quality control purposes.

Potential application of pristine and Al-doped graphyne-like BN nanosheet for detection of anticancer fluorouracil drug

We studied the potential application of the pristine and Al-doped graphyne-like BN nanosheets (Al-BN-yne) in 5-fluorouracil (5-FU) drug detection using DFT calculations. The 5-FU drug preferentially adsorbed via its oxygen atom on the B atom of pristine BN-yne with adsorption energy of - 11.7 kcal/mol and no effect on its electronic properties. Replacing a B atom by an Al atom significantly increased the sensitivity and reactivity of BN-yne to the 5-FU drug. Upon the 5-FU interaction with the Al-BN-yne, an energy of 20.3 kcal/mol is released, and the E_g of Al-BN-yne significantly decreased from 4.83 to 3.80 eV, increasing the electrical conductance. Thus, the Al-BN-yne sheet can generate an electronic signal after the 5-FU drug adsorption, being a promising electronic sensor for 5-FU detection. We predicted that the recovery time for 5-FU drug desorption from the Al-BN-yne sheet surface is 0.07 s, demonstrating that it benefits from a short recovery time.

Molecular Imprinting Prevents Environmental Contamination and Body Toxicity from Anticancer Drugs: An Update

Cancer has been responsible for high morbidity and mortality globally. The treatment of cancer is possible using different kinds of therapies using anticancer drugs if it is diagnosed at the right time. Nevertheless, their appropriate administration for maximum therapeutic effect and their elimination from the patient's body causing environmental problems are two big issues which could be successfully abated using molecular imprinted polymers (MIPs) owing to their unique features. In this review, we have compiled and discussed the works on the determination and controlled release of anticancer drugs based on MIPs. We also highlighted the current challenges and remedies, and the future direction of MIPs in this area.

Development of molecularly imprinted polymer nanoarrays of N-acryloyl-2-mercaptobenzamide on a silver electrode for ultratrace sensing of uracil and 5-fluorouracil

Graphical representation of development of mip-nanoarrays.

Molecularly imprinted polymer for recognition of 5-fluorouracil by RNA-type nucleobase pairing

A 6-aminopurine (adenine) derivative of bis(2,2'-bithienyl)methane, vis., 4-[2-(6-amino-9H-purin-9-yl)ethoxy]phenyl-4-[bis(2,2'-bithienyl)methane] or Ade-BTM, was designed and synthesized for recognition of 5-fluorouracil (FU), an antitumor chemotherapy agent, by RNA-type (nucleobase pairing)-driven molecular imprinting. The prepolymerization complex stoichiometry involved one FU molecule and two molecules of the Ade-BTM functional monomer. Molecular structure of this complex was thermodynamically optimized via density functional theory at the B3LYP/3-21G* level. The stability constant of the FU-Ade-BTM complex of 1:2 stoichiometry was K = 2.17(±0.07) × 10(7) M(-2), as determined by titration with quenching of fluorescence of the bis(2,2'-bithienyl)methane moiety of Ade-BTM by the FU titrant, in benzonitrile, at 352 nm excitation. Next, (5-fluorouracil)-templated molecularly imprinted polymer (MIP-FU) films were deposited on indium-tin oxide (ITO) or Au film-coated glass slides, Pt disk electrodes, or 10-MHz quartz crystal resonators by potentiodynamic electropolymerization from solution of FU, Ade-BTM, and tris([2,2'-bithiophen]-5-yl)methane (TTM) cross-linking monomer at FU:Ade-BTM:TTM = 1:2:3 mol ratio. Then UV-visible and Fourier transform infrared (FT-IR) spectra of the MIP-FU films were recorded to confirm the FU template presence in the MIP-FU film and its subsequent release by extraction with methanol from this film. For determination of the stability constant of the complex of the MIP cavity and FU, piezoelectric microgravimetry (PM) under both batch- and flow-injection analysis conditions was used. For sensing application, three different transduction platforms [differential pulse voltammetry (DPV), capacitive impedimetry (CI), and PM] were integrated with the MIP-FU recognition unit. The limit of detection (LOD) was 56 nM, 75 nM, and 0.26 mM, for these chemosensors, respectively, indicating suitability of the former two for FU determination in blood plasma or serum (~500 nM). Moreover, the CI chemosensor was appreciably more sensitive to FU than to their common interferences.