Review on Nanomaterial-Based Melamine Detection

Nanoparticle-based immunosensors for enhanced DNA analysis in oral cancer: A systematic review

To investigate the diagnostic and therapeutic potential of nanoparticle (NP)-based immunosensors in the field of oral cancer. PubMed, Embase, Scopus, Web of Science, and Google Scholar databases were explored for NP applications in oral cancer. Data extraction in terms and quality assessment of all the articles were done. Out of 147, 17 articles were included in this review. A majority of the studies showed improved sensitivity and specificity for saliva analysis using an enzyme-linked immunosorbent assay based on gold NPs, improving early identification. Additionally, novel therapeutic approaches, utilising NP-based immunosensors, demonstrated targeted drug delivery, coupled chemo-photothermal therapy, and gene silencing. Imaging methods have made it possible to distinguish between malignant and healthy states, such as surface-enhanced Raman scattering and optical coherence tomography. The reviews' findings highlight the transformational potential of NP-based immunosensors in addressing the difficulties associated with diagnosing and treating oral cancer. However, for an accurate interpretation and application of NP-based solutions in clinical practise, it is essential to be thoroughly aware of the intricacies involved, and the synthesised data in this review support the continued investigation and improvement of NP-based therapies in the ongoing effort to improve the management of oral cancer.

Using the photo-enhanced barrier effect on electrochemical response for highly sensitive detection of melamine

Melamine added to milk powder can lead to kidney injury and even death, but rapid detection is still hard due to the strong interference of milk powder solution. Herein, the CC/CeO2/CNPs mesh was constructed to detect melamine by using the photo-enhanced barrier effects on electrochemical response. Schottky barrier was regulated effectively to produce electrochemical response to melamine by photo-induced electrostatic interaction, which exhibited strong resistance to interference in milk powder solution. Sensitivity was enhanced by nearly 5 times and the lowest detection limit was reduced as low as 0.274 nM. The obtained high recovery (100%-104%) and good stability in milk powder solution indicated the good potential for practical applications. It provides a new opportunity for achieving strong resistance to interference by using the photo-enhanced barrier driving effect on electrochemical response.

Current Insights into the Neurotoxicity of Melamine: A Comprehensive Review

Melamine, a heterocyclic nitrogen-rich triazine chemical compound, is widely used in various household products, including furniture, dinnerware, and kitchen appliances. The unauthorized addition of the mixture to various foodstuffs to misrepresent protein content resulted in catastrophic, frequently life-threatening health consequences for kids as well as canines and has garnered international attention. Numerous primary studies and evaluations have been focused on melamine toxicity's implications on kidney function. Despite the profusion of literature on melamine's nephrotoxicity, evidence regarding its toxicity to other organs remains scarce. A number of recent studies suggest melamine can disrupt central nervous system (CNS) function and bring about cognitive impairments, contradicting the commonly held belief that melamine's detrimental effects are limited to the urinary system. The accumulation of melamine in the body is linked to various adverse effects, including depression, impaired synaptic transmission, oxidative stress, and neurodegenerative diseases. Several mechanisms may lead to such complications. However, numerous safeguards against melamine accumulation have been identified. This review could shed light on the potential neurological effects and mechanisms underlying melamine toxicity. Afterward, we will dive into the body's possible protective mechanisms against melamine-induced toxicity.

Recent Advances in Fluorescent Nanoprobes for Food Safety Detection

Fluorescent nanoprobes show similar fluorescence properties to traditional organic dyes, but the addition of nanotechnology accurately controls the size, shape, chemical composition, and surface chemistry of the nanoprobes with unique characteristics and properties, such as bright luminescence, high photostability, and strong biocompatibility. For example, modifying aptamers or antibodies on a fluorescent nanoprobe provides high selectivity and specificity for different objects to be tested. Fluorescence intensity, life, and other parameters of targets can be changed by different sensing mechanisms based on the unique structural and optical characteristics of fluorescent nanoprobes. What's more, the detection of fluorescent nanoprobes is cost-saving, simple, and offers great advantages in rapid food detection. Sensing mechanisms of fluorescent nanoprobes were introduced in this paper, focusing on the application progress in pesticide residues, veterinary drug residues, heavy metals, microbes, mycotoxins, and other substances in food safety detection in recent years. A brief outlook for future development was provided as well.

Investigations on melamine-based uric acid kidney stone formation and its prevention by inhibitors

Melamine (Mel) as a milk powder adulterant came to light in September 2008, when a kidney stone disease (KSD) outbreak struck China. The mechanism of the formation of Mel-associated uric acid (UA) stones is relatively unknown. Therefore, in the present study, Mel's influence was explored at comparatively higher and lower concentrations in artificial urine. The parameter optimization performed when the Mel concentration in artificial urine was low, which revealed that higher pH values and lower UA concentration considerably delayed the induction of UA crystallization. When Mel concentration was increased relative to UA concentration, the induction time of UA crystallization decreased dramatically. At the highest concentration of Mel investigated (at UA-Mel molar ratio 1:1), PXRD analysis and SEM revealed a change in crystalline structure of the samples. Based on FTIR analysis, it was determined that UA-Mel interactions are essentially physical, because no new characteristic bands developed. Two inhibitors, namely tri-potassium citrate (TPC) and 3, 7-dimethylxanthine (DMX), were investigated for their inhibitory action on UA crystallization in the presence of Mel. DMX was observed to be more promising than TPC in delaying the induction of crystallisation and hence inhibiting crystal formation.

Metal-Organic Framework Fluorescence Sensors for Rapid and Accurate Detection of Melamine in Milk Powder

In this research, a simple, label-free, and ultra-sensitive fluorescent platform based on a metal-organic framework (MOF) has been developed to detect melamine in milk powder. This fluorescence sensor was fabricated from sensitized terbium (Tb)@NH₂-MIL-253 (Al) MOF using a hydrothermal method that involved combining the green emission of Tb (λ_em = 545 nm) with the blue emission of NH₂-MIL-253(Al) MOF (λ_em = 430 nm) under a single excitation wavelength (λ_ex = 335 nm). The fluorescence sensor was then used under optimized conditions (pH = 9.0; sensor concentration = 30 mg/L; response time = 30 s) to quantify melamine in milk powder. The accuracy, sensitivity, and reproducibility of this sensor were established compared to the high-performance liquid chromatography (HPLC) method. The linear range and lower limit of detection (LLOD, computed with 3σ/S) of the sensor were between 40-396.45 nM (equal to 25 µg/kg-0.25 mg/kg) and 40 nM (equal to 25 µg/kg), respectively, which is much less than the maximum residual level (MRL) for the detection of melamine in infant formula (1 mg/kg) and other foods/feeds (2.5 mg/kg). Additionally, the results had good agreement with the HPLC outcomes, suggesting that the NH₂-MIL-253(Al) MOF sensing probe has great precision and repeatability. To conclude, the new fluorescence sensor developed in this study can accurately and sensitively detect melamine in food samples, which may be useful for screening for adulteration of milk powders and other foods.

Emerging Biosensors for Oral Cancer Detection and Diagnosis—A Review Unravelling Their Role in Past and Present Advancements in the Field of Early Diagnosis

Oral cancer is a serious concern to people all over the world because of its high mortality rate and metastatic spread to other areas of the body. Despite recent advancements in biomedical research, OC detection at an early stage remains a challenge and is complex and inaccurate with conventional diagnostics procedures. It is critical to study innovative approaches that can enable a faster, easier, non-invasive, and more precise diagnosis of OC in order to increase the survival rate of patients. In this paper, we conducted a review on how biosensors might be an excellent tool for detecting OC. This review covers the strategies that use different biosensors to target various types of biomarkers and focuses on biosensors that function at the molecular level viz. DNA biosensors, RNA biosensors, and protein biosensors. In addition, we reviewed non-invasive electrochemical methods, optical methods, and nano biosensors to analyze the OC biomarkers present in body fluids such as saliva and serum. As a result, this review sheds light on the development of ground-breaking biosensors for the early detection and diagnosis of OC.

Rapid Detection of Nonprotein Nitrogen Adulterants in Milk Powder Using Point-Scan Raman Hyperspectral Imaging Technology

To develop a rapid detection method for nonprotein nitrogen adulterants, this experiment sets up a set of point-scan Raman hyperspectral imaging systems to qualitatively distinguish and quantitatively and positionally analyze samples spiked with a single nonprotein nitrogen adulterant and samples spiked with a mixture of nine nonprotein nitrogen adulterants at different concentrations (5 × 10-3 to 2.000%, w/w). The results showed that for samples spiked with single nonprotein nitrogen adulterants, the number of pixels corresponding to the adulterant in the region of interest increased linearly with an increase in the analyte concentration, the average coefficient of determination (R 2) was above 0.99, the minimum detection concentration of nonprotein nitrogen adulterants reached 0.010%, and the relative standard deviation (RSD) of the predicted concentration was less than 6%. For the sample spiked with a mixture of nine nonprotein nitrogen adulterants, the standard curve could be used to accurately predict the additive concentration when the additive concentration was greater than 1.200%. The detection method established in this study has good accuracy, high sensitivity, and strong stability. It provides a method for technical implementation of real-time and rapid detection of adulterants in milk powder at the port site and has good application and promotion prospects.

A Fluorescence-Based Chemical Sensor for Detection of Melamine in Aqueous Solutions

Melamine, an industrial chemical, receives wide attention nowadays because of its unethical usage as a nitrogen enhancer in protein-rich foods and dairy products. Since most of the existing melamine detection methods are highly expensive and time-consuming, high sensitivity biosensor-based detection methods have arisen in the scientific literature as promising alternatives. This study reports the design, synthesis, and fluorescent investigations of a carbazole-based sensor (CB) for the detection of melamine in aqueous solutions. The titration studies and microplate experiments on a CB-cyanuric acid mixture (CB-CA) with melamine suggested that the novel sensor could detect melamine even at very low concentrations in both aqueous solutions and dairy samples.

Progress in Metal-Organic Frameworks Facilitated Mercury Detection and Removal

Metal Organic Frameworks (MOFs) are noted as exceptional candidates towards the detection and removal of specific analytes. MOFs were reported in particular for the detection/removal of environmental contaminants, such as heavy metal ions, toxic anions, hazardous gases, explosives, etc. Among heavy metal ions, mercury has been noted as a global hazard because of its high toxicity in the elemental (Hg0), divalent cationic (Hg2+), and methyl mercury (CH3Hg+) forms. To secure the environment and living organisms, many countries have imposed stringent regulations to monitor mercury at all costs. Regarding the detection/removal requirements of mercury, researchers have proposed and reported all kinds of MOFs-based luminescent/non-luminescent probes towards mercury. This review provides valuable information about the MOFs which have been engaged in detection and removal of elemental mercury and Hg2+ ions. Moreover, the involved mechanisms or adsorption isotherms related to sensors or removal studies are clarified for the readers. Finally, advantages and limitations of MOFs in mercury detection/removal are described together with future scopes.

Inorganic-Diverse Nanostructured Materials for Volatile Organic Compound Sensing

Environmental pollution related to volatile organic compounds (VOCs) has become a global issue which attracts intensive work towards their controlling and monitoring. To this direction various regulations and research towards VOCs detection have been laid down and conducted by many countries. Distinct devices are proposed to monitor the VOCs pollution. Among them, chemiresistor devices comprised of inorganic-semiconducting materials with diverse nanostructures are most attractive because they are cost-effective and eco-friendly. These diverse nanostructured materials-based devices are usually made up of nanoparticles, nanowires/rods, nanocrystals, nanotubes, nanocages, nanocubes, nanocomposites, etc. They can be employed in monitoring the VOCs present in the reliable sources. This review outlines the device-based VOC detection using diverse semiconducting-nanostructured materials and covers more than 340 references that have been published since 2016.

SYBR Green I promotes melamine binding to poly-thymine DNA and FRET-based ratiometric sensing

Using SYBR Green I for DNA melting experiments, polythymine DNA binding to melamine was found to be an intramolecular reaction, allowing the design of a FRET-based biosensor and its sensitivity was enhanced by SYBR Green I.

Review on Sensing Applications of Perovskite Nanomaterials

Recently, perovskite-based nanomaterials are utilized in diverse sustainable applications. Their unique structural characteristics allow researchers to explore functionalities towards diverse directions, such as solar cells, light emitting devices, transistors, sensors, etc. Many perovskite nanomaterial-based devices have been demonstrated with extraordinary sensing performance to various chemical and biological species in both solid and solution states. In particular, perovskite nanomaterials are capable of detecting small molecules such as O2, NO2, CO2, etc. This review elaborates the sensing applications of those perovskite materials with diverse cations, dopants and composites. Moreover, the underlying mechanisms and electron transport properties, which are important for understanding those sensor performances, will be discussed. Their synthetic tactics, structural information, modifications and real time sensing applications are provided to promote such perovskite nanomaterials-based molecular designs. Lastly, we summarize the perspectives and provide feasible guidelines for future developing of novel perovskite nanostructure-based chemo- and biosensors with real time demonstration.

A Review: Electrochemical Biosensors for Oral Cancer

Oral cancer poses a serious threat worldwide owing to its soaring case-fatality rate and its metastatic characteristics of spreading to the other parts of the body. Despite the recent breakthroughs in biomedical sciences, the detection of oral cancer at an early stage is still challenging. Conventional diagnosis in clinics and optical techniques to detect oral cancer in the initial stages are quite complicated as well as not completely accurate. To enhance the survival rate of oral cancer patients, it is important to investigate the novel methodologies that can provide faster, simpler, non-invasive, and yet ultraprecise detection of the onset of oral cancer. In this review, we demonstrate the promising aspects of an electrochemical biosensor as an ideal tool for oral cancer detection. We discuss the cutting-edge methodologies utilizing various electrochemical biosensors targeting the different kinds of biomarkers. In particular, we emphasize on electrochemical biosensors working at the molecular levels, which can be classified into mainly three types: DNA biosensors, RNA biosensors and protein biosensors according to the types of the analytes. Furthermore, we focus on the significant electrochemical methods including cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) to analyze the oral cancer biomarkers (such as IL-6, IL-8, CYFRA 21-1, CD 59 and CIP2A) present in body fluids including saliva and serum, using non-invasive manner. Hence, this review provides essential insights into the development of pioneering electrochemical biosensors for the detection of oral cancer at an early stage.

Silver Nanoparticles as Colorimetric Sensors for Water Pollutants

This review provides an up-to-date overview on silver nanoparticles-based materials suitable as optical sensors for water pollutants. The topic is really hot considering the implications for human health and environment due to water pollutants. In fact, the pollutants present in the water disturb the spontaneity of life-related mechanisms, such as the synthesis of cellular constituents and the transport of nutrients into cells, and this causes long / short-term diseases. For this reason, research continuously tends to develop always innovative, selective and efficient processes / technologies to remove pollutants from water. In this paper we will report on the silver nanoparticles synthesis, paying attention to the stabilizers and mostly used ligands, to the characterizations, to the properties and applications as colorimetric sensors for water pollutants. As water pollutants our attention will be focused on several heavy metals ions, such as Hg(II), Ni(II),Cu(II), Fe(III), Mn(II), Cr(III/V) Co(II) Cd(II), Pb(II), due to their dangerous effects on human health. In addition, several systems based on silver nanoparticles employed as pesticides colorimetric sensors in water will be also discussed. All of this with the aim to provide to readers a guide about recent advanced silver nanomaterials, used as colorimetric sensors in water.

Noble Metal Nanoparticles-Based Colorimetric Biosensor for Visual Quantification: A Mini Review

Nobel metal can be used to form a category of nanoparticles, termed noble metal nanoparticles (NMNPs), which are inert (resistant to oxidation/corrosion) and have unique physical and optical properties. NMNPs, particularly gold and silver nanoparticles (AuNPs and AgNPs), are highly accurate and sensitive visual biosensors for the analytical detection of a wide range of inorganic and organic compounds. The interaction between noble metal nanoparticles (NMNPs) and inorganic/organic molecules produces colorimetric shifts that enable the accurate and sensitive detection of toxins, heavy metal ions, nucleic acids, lipids, proteins, antibodies, and other molecules. Hydrogen bonding, electrostatic interactions, and steric effects of inorganic/organic molecules with NMNPs surface can react or displacing capping agents, inducing crosslinking and non-crosslinking, broadening, or shifting local surface plasmon resonance absorption. NMNPs-based biosensors have been widely applied to a series of simple, rapid, and low-cost diagnostic products using colorimetric readout or simple visual assessment. In this mini review, we introduce the concepts and properties of NMNPs with chemical reduction synthesis, tunable optical property, and surface modification technique that benefit the development of NMNPs-based colorimetric biosensors, especially for the visual quantification. The “aggregation strategy” based detection principle of NMNPs colorimetric biosensors with the mechanism of crosslinking and non-crosslinking have been discussed, particularly, the critical coagulation concentration-based salt titration methodology have been exhibited by derived equations to explain non-crosslinking strategy be applied to NMNPs based visual quantification. Among the broad categories of NMNPs based biosensor detection analyses, we typically focused on four types of molecules (melamine, single/double strand DNA, mercury ions, and proteins) with discussion from the standpoint of the interaction between NMNPs surface with molecules, and DNA engineered NMNPs-based biosensor applications. Taken together, NMNPs-based colorimetric biosensors have the potential to serve as a simple yet reliable technique to enable visual quantification.