Reduce Graphene Oxide/Fe3O4 Nanocomposite Biosynthesized by Sour Lemon Peel; Using as Electro-catalyst for Fabrication of Vanillin Electrochemical Sensor in Food Products Analysis and Anticancer Activity

Heterojunction of branched benzopyrazine-based polymers coating on graphene for electrochemical sensing of vanillin

Vanillin finds widespread applications in various industries, such as food, pharmaceuticals, and cosmetics. However, excessive intake of vanillin could pose risks to human health. This study detailed the successful creation of a heterojunction of branched benzopyrazine-based polymers coating on graphene (CMP-rGO) through the Sonogashira-Hagihara coupling reaction. Utilizing the CMP-rGO, a novel electrochemical sensor for vanillin detection was developed. Besides, the synthesized materials were validated using standard characterization techniques. Both cyclic voltammetry and differential pulse voltammetry techniques were employed to investigate vanillin's electrochemical characteristics on this sensor. The findings indicated a significant enhancement in vanillin's electrochemical signal responsiveness with the application of CMP-rGO. Under optimal conditions, the sensor demonstrated a linear response to vanillin concentrations ranging from 0.08 to 33 μM and achieved a detection limit as low as 0.014 μM. Also, the constructed electrochemical sensor exhibited excellent selectivity, stability, and reproducibility. It has been effectively employed to detect vanillin in real samples such as human serum, human urine, and vanillin tablets, with a recovery rate of 99.13-103.6 % and an RSD of 3.46-1.26 %. Overall, this innovative sensor offers a novel approach to the efficient and convenient detection of vanillin.

A novel magneto-mediated electrochemical biosensor integrated DNAzyme motor and hollow nanobox-like Pt@Ni-Co electrocatalyst as dual signal amplifiers for vanilla detection

Herein, a novel magneto-mediated electrochemical aptasensor using the signal amplification technologies of DNAzyme motor and electrocatalyst for vanilla (VAN) detection was fabricated. The D/B duplex, formed by the DNAzyme motor that was each silenced by a blocker, and hairpin DNA1 (H1) containing adenosine ribonucleotide (rA) site were tethered on the sites of the gold nanoparticles@hollow porphyrinic-Metal-organic framework/polyethyleneimine-reduced graphene oxide (AuHPCN-222/PEI-rGO)-modified gold electrode (AuE). Then, after homogeneous and specific recognition in the presence of the VAN, trigger DNA was released and enriched by magnetic separation technique and introduced to the sensing platform to activate the DNAzyme motor, which efficiently improved target recognition capability and avoided the obstacle of multiple DNA strands tangling. More interestingly, the activated DNAzyme motor could repeatedly bind to and cleave H1 in the presence of Mg2+, leading to the exposure of a plethora of capture probes. The thionine (Thi) functionalized hairpin DNA2 (H2)-Pt@Ni-Co as signal probes could hybridize with capture probes. Additionally, the Pt@Ni-Co electrocatalysts presented catalytic activity towards Thi to obtain stronger electrochemical signals. VAN with concentrations ranging from 1 × 10-6 to 10 μM was determined and a detection limit was down to 0.15 pM. The designed electrochemical sensor was highly selective with specificity, stability, reproducibility, and reliable capability for monitoring the VAN in real samples.

A carbon based-screen-printed electrode amplified with two-dimensional reduced graphene/Fe3O4 nanocomposite as electroanalytical sensor for monitoring 4-aminophenol in environmental fluids

The analysis water pollutants are so important strategy for investigation of water quality. On the other hand, 4-aminophenol is known as a hazardous and high-risk compound for humans, and its detection and measurement is very important for investigating the quality of surface and groundwater. In this study, graphene/Fe₃O₄ nanocomposite was synthesized by a simple chemical method and characterized by EDS and TEM methods and results showed Nano spherical shape of Fe₃O₄ nanoparticle with diameter about 20 nM decorated at surface of 2D reduce graphene nanosheet (2D-rG-Fe₃O₄). The 2D-rG-Fe₃O₄ was used as excellent catalyst at surface of carbon-based screen-printed electrode (CSPE) and used as electroanalytical sensor in monitoring and determination of 4-aminophenol in waste water sample. The results confirmed improving ∼4.0 times in oxidation signal and reducing 120 mV in oxidation potential of 4-aminophenol at surface of 2D-rG-Fe₃O₄/CSPE compare to CSPE, respectively. The electrochemical investigation showed pH dependence behavior with equal value of electron and proton for -aminophenol at surface of 2D-rG-Fe₃O₄/CSPE. Using square wave voltammetry method (SWV), the 2D-rG-Fe₃O₄/CSPE successfully monitored 4-aminophenol in the concentration range 1.0 nM-200 μM. Finally, 2D-rG-Fe₃O₄/CSPE monitored 4-aminophenol in the different environmental fluids such as urban waste water, industrial waste water and river samples with recovery range 97.2%-104.3% that confirm powerful ability of 2D-rG-Fe₃O₄/CSPE as analytical tool.

Recent Advances in Nanomaterials of Group XIV Elements of Periodic Table in Breast Cancer Treatment

Breast cancer is one of the most common malignancies and a leading cause of cancer-related mortality among women worldwide. The elements of group XIV in the periodic table exhibit a wide range of chemical manners. Recently, there have been remarkable developments in the field of nanobiomedical research, especially in the application of engineered nanomaterials in biomedical applications. In this review, we concentrate on the recent investigations on the antiproliferative effects of nanomaterials of the elements of group XIV in the periodic table on breast cancer cells. In this review, the data available on nanomaterials of group XIV for breast cancer treatment has been documented, providing a useful insight into tumor biology and nano-bio interactions to develop more effective nanotherapeutics for cancer patients.

Nanopore-based aptasensor for label-free and sensitive vanillin determination in food samples

Dielectric breakdown technique was utlised to fabricate 5-6 nm nanopores for vanillin detection in various food samples. A highly selective aptamer (Van_74) with high binding affinity towards vanillin was used as capture probe. Under optimal conditions, aptamer/vanillin complex translocation induced deeper events than the bare aptamer. As a result, the proposed nanopore aptasensor exhibits a linear range from 0.5 to 5 nM (R² = 0.972) and a low detection limit of 500 pM, which is significantly better than conventional platforms. Furthermore, our aptasensor showed excellent immunity against different interferons and was used to detect vanillin in different food samples. The food sample measurements were confirmed with an additional UV-Vis assay, the results of the two techniques were statistically evaluated and showed no statistically significant difference. Hence, this work represents a proof-of-concept involving the design and testing of aptamer/nanopore sensors for small molecules detection, which plays a critical role in food safety.

A review on nanomaterial-based electrochemical sensors for determination of vanillin in food samples

Vanillin is an organic compound that not only acts as a flavoring and fragrance enhancer in some foods, but also can have antioxidant, anti-inflammatory, anti-cancer and anti-depressant effects. Nevertheless, its excessive use can be associated with side effects on human health. Consequently, there is a need to achieve a rapid vanillin determination approach to enhance food safety. The diversity and high sensitivity of analytical approaches has led researchers to use more advanced and efficient methods providing quantitative and qualitative outcomes in complex matrices. Among these, prominent attention has been drawn to electrochemical sensors for reasons such as reliability, simplicity, cost-effectiveness, portability, selectivity, and ease of operation, especially for the determination of vanillin. Nanomaterials are a good candidate for sensor construction due to their commendable physicochemical attributes. Some advanced nanostructures with promising platforms for high-sensitivity, highly selective, and long-lasting electrochemical sensors include graphene (Gr) and its derivatives, graphite carbon nitride (g-C₃N₄), carbon nanotubes (CNTs), metal nanoparticles, metal organic frameworks, carbon nanofibers (CNFs) and quantum dots. Study about sizes, dimensions, and morphologies of nanomaterials makes strong candidates for improving sensitivity or selectivity according to electrocatalytic abilities. The low LOD and wide linear range of samples demonstrated an excellent catalytic performance towards the vanillin oxidation. Some investigations have reported the synergistic effects like great conductivity of carbon nanomaterials which improved the electrocatalytic performance of nanocomposites which demonstrated the estimable sensitivity of nanomaterial-supported electrochemical sensors for determination of vanillin concentrations. The sensors which have reported have a commendable response to practical potential and evaluated in biscuit, pudding powder, chocolate, custard specimens and etc. sensitivity, stability, reproducibility and repeatability of suggested sensor were investigated. The present review article scrutinizes recent advances in the fabrication of nanomaterial-based electrochemical sensors to detect vanillin in various food matrices.

A new electroanalytical approach for sunset yellow monitoring in fruit juices based on a modified sensor amplified with nano-catalyst and ionic liquid

The determination of food additives is one of the major points in the food industry that directly is relative to human health. This research work focused on sensing and monitoring sunset yellow as azo additive dyes in fruit juices using an electrochemical sensor amplified with Ni doped Pt decorated carbon nanotubes (NiO/Pt/CNTs) as nano-catalyst and 1-hexyl-3-methylimidazolium chloride ([HMIM][Cl]) as an ionic liquid binder. Carbon paste electrode (CPE) amplified with NiO/Pt/CNTs and [HMIM][Cl] (CPE/([HMIM][Cl])/NiO/Pt/CNTs) improved the sensitivity of sunset yellow sensing in aqueous solution in acidic condition and successfully monitored this azo dye in concentration range 1.0 nM-280 μM with detection limit 0.4 nM. On the other hand, the CPE/([HMIM][Cl])/NiO/Pt/CNTs was used for sensing and analysis of sunset yellow in different fruit juices, and recovery data between 98.65% and 103.66% confirmed the powerful ability of sensor for monitoring of sunset yellow in food samples.