Sucrose capped gold nanoparticles as a plasmonic chemical sensor based on non-covalent interactions: Application for selective detection of vitamins B1 and B6 in brown and white rice food samples

Progress in the design of portable colorimetric chemical sensing devices

The need for precise determination of heavy metals, anions, biomolecules, pesticides, drugs, and other substances is vital across clinical, environmental, and food safety domains. Recent years have seen significant progress in portable colorimetric chemical sensing devices, revolutionizing on-the-spot analysis. This review offers a comprehensive overview of these advancements, covering handheld colorimetry, RGB-based colorimetry, paper-based colorimetry, and wearable colorimetry devices. It explores the underlying principles, functional materials (chromophoric reagents/dyes and nanoparticles), detection mechanisms, and their applications in environmental monitoring, clinical care, and food safety. Noble metal nanoparticles (NPs) have arisen as promising substitutes in the realm of sensing materials. They display notable advantages, including heightened sensitivity, the ability to fine-tune their plasmonic characteristics for improved selectivity, and the capacity to induce visible color changes, and simplifying detection. Integration of NPs fabricated paper device with smartphones and wearables facilitates reagent-free, cost-effective, and portable colorimetric sensing, enabling real-time analysis and remote monitoring.

A smartphone digital image colorimetric method based on nanoparticles for determination of lamotrigine

Aim: A colorimetric approach for quantification of lamotrigine using spectrophotometric and smartphone image analysis is described in this study. Methods: For full optimization and validation procedures, UV-visible spectroscopy was used, and image analysis was carried out with the help of an app (PhotoMetrix PRO®). Then, as a multivariate calibration method, parallel factor analysis was used for data analysis. Results: The results demonstrated the capacity of these methods to estimate lamotrigine concentrations in the range of 0.1-7.0 μg.ml-1 in exhaled breath condensate, indicating the value of using digital images and smartphone applications in combination with chemometric tools. Conclusion: The image analysis can be superior for its fast and reliable lamotrigine analysis in biological samples.

Sweet, Sugar-Coated Hierarchical Platinum Nanostructures for Easy Support, Heterogenization and Separation

Metal nanoparticles are increasingly gaining interest in the field of heterogeneous catalysis. Here, we present a novel strategy for synthesizing sugar-coated platinum nanostructures (SC-Pt-NS) from the carbohydrates sucrose and D(-)-fructose. In the synthesis from a mixture of H2PtCl6·6H2O, the carbohydrate in an ionic liquid (IL) yielded primary particles of a homogeneous average size of ~10 nm, which were aggregated to hierarchical Pt nanostructures of ~40–65 nm and surrounded or supported by the carbohydrate. These sugar-coated platinum nanostructures present a facile way to support and heterogenize nanoparticles, avoid leaching and enable easier separation and handling. The catalytic activity of the SC-Pt-NS was shown in the hydrosilylation test reaction of phenylacetylene with triethylsilane, where very high turnover frequency (TOF) values of up to 87,200 h−1 could be achieved, while the platinum metal leaching into the product was very low.

Sensitive and highly selective colorimetric biosensing of vitamin-C and vitamin-B1 by flavoring agent-based silver nanoparticles

A sensitive scheme was established for the detection of vitamin C (Ascorbic acid) and vitamin B1 (Thiamin HCl) using Maltol capped AgNPs (McAgNPs) as colorimetric sensor. The designed scheme showed an instant alteration in color from yellow to orange and green for vitamin-C and vitamin B1 sequentially. The probe was sensitive in a concentration range of (0-1 µM) with limit of detection 0.064 and 0.038 µM for vitamin C and vitamin B1 sequentially. The interaction mechanism between vitamin C and vitamin B1 and McAgNPs was evaluated by visible spectroscopy, FTIR, and AFM. Vitamin C attaches on the surface of nanoparticles by C=O group, while OH, C-S-C, and NH₂ groups are involved in the binding of vitamin B1 with McAgNPs. The Vit-C/Vit-B1-McAgNPs complexes were stable over a wide range of pHs. The size of McAgNPs increased after the interaction of vitamin C/vitamin B1 from 30-40 nm to 500 and 400 nm sequentially. The scheme was successfully applied for the detection of vitamin C and vitamin B1 in urine, plasma, water, and commercial pharmaceutical tablets with good recoveries. The scheme was ascertained to be more sensitive than many other formerly described schemes.

Investigation on the Peroxidase-like Activity of Vitamin B6 and Its Applications in Colorimetric Detection of Hydrogen Peroxide and Total Antioxidant Capacity Evaluation

The peroxidase-like activity of vitamin B6 (VB6) was firstly demonstrated by catalyzing the peroxidase chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) at the existence of H2O2. The influence of different factors on the catalytic property of VB6, including pH, temperature, VB6 concentration, and incubation time, were investigated. The steady-state kinetic study results indicate that VB6 possesses higher affinity to H2O2 than natural horseradish peroxidase and some other peroxidase mimics. Besides, the radical quenching experiment results confirm that hydroxyl radical (•OH) accounts for the catalytic process. Based on the excellent peroxidase-like catalytic activity of VB6, the colorimetric methods for H2O2 and gallic acid (GA) detection were developed by measuring the absorbance variance of the catalytic system. Under the optimal conditions, the linear ranges of the methods for H2O2 and GA determination with good selectivity are 50.0–600.0 μM and 10.0–50.0 μM, respectively. In addition, the developed method was applied in the detection of H2O2 in milk samples and evaluation of total antioxidant capacity of different tea infusions. This study may broaden the application prospect of VB6 in environmental and biomedical analysis fields, contribute to profound insight of the physiological functions of VB6, as well as lay foundation for further excavation of small-molecule peroxidase mimics.

Antiviral nanoparticle ligands identified with datamining and high-throughput virtual screening

To help contain the spread of the COVID-19 pandemic and to protect front-line workers, new antiviral measures are required. Antiviral nanoparticles are one such possible measure. Metal nanoparticles made from a variety of metals including gold, silver, and copper can kill or disable viruses that cause significant health problems in humans (such as SARS-CoV-2, HIV, or influenza). To promote interaction between nanoparticles and viruses the stabilizing ligands on the nanoparticle surface should be optimized for docking with proteins. The enormous chemical space of possible nanoparticle ligands makes this optimization experimentally and computationally intractable. Here we present a datamining-based study that searched for nanoparticle ligands that have previously been used, and computationally tested these for their ability to dock with the SARS-CoV-2 spike glycoprotein. These ligands will coat future antiviral nanoparticles to be used outside of the body, not as drugs. The best of these ligands identified were: nitric acid (score: 0.95), phosphoroselenoic acid (score: 0.88), hydroxyammonium (score: 0.83), pyrophosphoric acid (score: 0.81). Inspection of the best of these ligands has suggested design principles for future antiviral nanoparticle ligands, and we suggest further ligands based on these principles. These results will be used to inspire further in vitro and in silico experimentation to accelerate the development of antiviral nanoparticles.

To help contain the spread of the COVID-19 pandemic and to protect front-line workers, new antiviral measures are required.

A simple and cost-effective paper-based and colorimetric dual-mode detection of arsenic(iii) and lead(ii) based on glucose-functionalized gold nanoparticles

We report a simple and cost-effective paper-based and colorimetric dual-mode detection of As(iii) and Pb(ii) based on glucose-functionalized gold nanoparticles under optimized conditions. The paper-based detection of As(iii) and Pb(ii) is based on the change in the signal intensity of AuNPs/Glu fabricated on a paper substrate after the deposition of the analyte using a smartphone, followed by processing with the ImageJ software. The colorimetric method is based on the change in the color and the red shift of the localized surface plasmon resonance (LSPR) absorption band of AuNPs/Glu in the region of 200-800 nm. The red shift (Δλ) of the LSPR band observed was from 525 nm to 660 nm for As(iii) and from 525 nm to 670 nm for Pb(ii). The mechanism of dual-mode detection is due to the non-covalent interactions of As(iii) and Pb(ii) ions with glucose molecule present on the surface AuNPs, resulting in the aggregation of novel metal nanoparticles. The calibration curve gave a good linearity range of 20-500 μg L-1 and 20-1000 μg L-1 for the determination of As(iii) and Pb(ii) with the limit of detection of 5.6 μg L-1 and 7.7 μg L-1 for both metal ions, respectively. The possible effects of different metal ions and anions were also investigated but did not cause any significant interference. The employment of AuNPs/Glu is successfully demonstrated for the determination of As(iii) and Pb(ii) using paper-based and colorimetric sensors in environmental water samples.

Au–Ag core–shell composite nanoparticles as a selective and sensitive plasmonic chemical probe for l-cysteine detection in Lens culinaris (lentils)

The present work reported is a simple and selective method for the colorimetrical detection of l-cysteine in Lens culinaris (or lentils) using Au–Ag core–shell (Au core Ag shell) composite nanoparticles as a chemical probe.

Food safety monitoring of the pesticide phenthoate using a smartphone-assisted paper-based sensor with bimetallic Cu@Ag core-shell nanoparticles

Presently, the use of several pesticides has been continuously rising owing to the increase in the production of food materials to meet the requirements of the growing population of the world. The safety of food materials with regards to pesticides is an important health concern for people. With this aim, we have developed a smartphone-assisted paper-based sensor impregnated with citrate capped Cu@Ag core-shell nanoparticles (NPs) for selective determination of phenthoate pesticides in water and food samples. The mechanism for selective detection is based on the high affinity of phenthoate to interact with silver NPs present on the surface of CuNPs, which results in aggregation and a change in the color of the paper device. Furthermore, the proposed mechanism and interaction of phenthoate with Cu@Ag NPs was theoretically investigated by density functional theory (DFT) using Gaussian 16.0 software. The linear range for the determination of phenthoate was found in the range of 50-1500 μg L-1, with a limit of detection of 15 μg L-1, and a 92.6 to 97.4% recovery, and the interference studies demonstrated the selectivity for the determination of the target analyte from complex sample matrices. Finally, paper impregnated with Cu@Ag was exploited for the monitoring of the phenthoate pesticide in different water and food samples. The advantages of this paper-based sensor, coupled with a smartphone readout system, are that is it is user-friendly, easy-to-use, cost-effective, and can be applied at the sample source compared to sophisticated analytical instruments.

Novel synthesis of a dual fluorimetric sensor for the simultaneous analysis of levodopa and pyridoxine

Herein, a fluorimetric sensor was fabricated based on molecularly imprinted polymers (MIPs) with two types of carbon dots as fluorophores. The MIPs produced had similar excitation wavelengths (400 nm) and different emission wavelengths (445 and 545 nm). They were used for the simultaneous analysis of levodopa and pyridoxine. First, two types of carbon dots, i.e. nitrogen-doped carbon dots (NCDs) with a quantum yield of 43%, and carbon dots from o-phenylenediamine (O-CDs) with a quantum yield of 17%, were prepared using the hydrothermal method. Their surfaces were then covered with MIPs through the reverse microemulsion method. Finally, a mixture of powdered NCD@MIP and O-CD@MIP nanocomposites was used for the simultaneous fluorescence measurement of levodopa and pyridoxine. Under optimal conditions using response surface methodology and Design-Expert software, a linear dynamic range of 38 to 369 nM and 53 to 457 nM, and detection limits of 13 nM and 25 nM were obtained for levodopa and pyridoxine, respectively. The capability of the proposed fluorimetric sensor was investigated in human blood serum and urine samples. Graphical Abstract Schematic representation of nitrogen-doped carbon dots (NCDs), carbon dots from o-phenylenediamine (O-CDs), NCDs coated with imprinted polymers (NCD@MIPs), and O-CDs coated with imprinted polymers (O-CD@MIPs) in the presence and absence of levodopa and pyridoxine.

Self-assembled drug loaded glycosyl-protein metal nanoconstruct: Detailed synthetic procedure and therapeutic effect in solid tumor treatment

Nanotechnology-based drug delivery research has largely focused on developing well efficient localized delivery therapeutic agents to overcome the limitations of non-specificity and toxicity of conventional chemotherapy. Herein, we constructed a nanoplatform based on a self-assembled polysaccharide-protein conjugate to deliver anti-tumor drug doxorubicin and gold nanoparticles (DOX@PST-BSA AuNPs) for cancer therapy. The self-assembled DOX@PST-BSA AuNPs exhibited higher stability and thermal properties which enable them for drug delivery via passive targeting. The fluorescent property of the drug contributes to the self-monitoring of NPs Biodistribution in vitro and in vivo. Furthermore, the NPs showed negligible cytotoxicity and tissue accumulation in normal cells in vivo. Importantly, the NPs could load the anti-tumor drug with high encapsulation efficiency and competently delivered into the tumor microenvironment thereby inhibit tumor growth significantly through apoptotic induction. Notably, DOX@PST-BSA AuNPs exhibits low systemic toxicity and very few side effects in vivo. Based on the explored features, these NPs could serve as a promising multifunctional drug delivery nanoplatform for cancer therapy.

L-cysteine modified silver nanoparticles for selective and sensitive colorimetric detection of vitamin B1 in food and water samples

The use of L-cysteine modified silver nanoparticles (Cys-capped AgNPs) as a colorimetric probe for determination of vitamin B1 (thiamine) is described in the present work. This method is based on the measurement of red shift of localized surface plasmon resonance (LSPR) band of Cys-capped AgNPs in the region of 200–800 nm. The color of Cys-capped AgNPs was changed from yellow to colorless by the addition of vitamin B1. The mechanism for detection of vitamin B1 is based on the electrostatic interaction between positively charged vitamin B1, which causes the red shift of LSPR band from 390 nm to 580 nm. The interaction between Cys-capped AgNPs and vitamin B1 was theoretically explored by density function theory (DFT) using LANL2DZ basis sets with help of Gaussian 09 (C.01) program. The morphology, size distribution and optical properties of Cys-capped AgNPs were characterized by transmission electron microscope (TEM), UV-Visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS) techniques. The method is linear in the range of 25–500 μg mL⁻¹ with correlation coefficient (R²) 0.992 and limit of detection of 7.0 μg mL⁻¹. The advantages of using Cys-capped AgNPs as a chemical sensor in colorimetry assay are being simple, low cost and selective for detection of vitamin B1 from food (peas, grapes and tomato) and environmental (river, sewage and pond) water samples.

Application of Nanotechnology in Cancer Diagnosis and Therapy - A Mini-Review

Cancer is a leading cause of death and poor quality of life globally. Even though several strategies are devised to reduce deaths, reduce chronic pain and improve the quality of life, there remains a shortfall in the adequacies of these cancer therapies. Among the cardinal steps towards ensuring optimal cancer treatment are early detection of cancer cells and drug application with high specificity to reduce toxicities. Due to increased systemic toxicities and refractoriness with conventional cancer diagnostic and therapeutic tools, other strategies including nanotechnology are being employed to improve diagnosis and mitigate disease severity. Over the years, immunotherapeutic agents based on nanotechnology have been used for several cancer types to reduce the invasiveness of cancerous cells while sparing healthy cells at the target site. Nanomaterials including carbon nanotubes, polymeric micelles and liposomes have been used in cancer drug design where they have shown considerable pharmacokinetic and pharmacodynamic benefits in cancer diagnosis and treatment. In this review, we outline the commonly used nanomaterials which are employed in cancer diagnosis and therapy. We have highlighted the suitability of these nanomaterials for cancer management based on their physicochemical and biological properties. We further reviewed the challenges that are associated with the various nanomaterials which limit their uses and hamper their translatability into the clinical setting in certain cancer types.

Progress in research on gold nanoparticles in cancer management

INTRODUCTION

The rapid advancement of nanotechnology in recent years has fuelled burgeoning interest in the field of nanoparticle research, particularly its application in cancer management. At present, there seems to be heightened interest in the application of gold nanoparticles (AuNPs) to the management of cancer, encompassing diagnosis, monitoring, and treatment. AuNPs could be used as drug delivery agents that target cancer cells or in gene therapy. These efforts are undertaken in the hope of revolutionizing current methods and strategies for cancer treatment. This review will focus on the current applications of AuNPs in cancer management. OBJECTIVES, DATA SOURCES, STUDY APPRAISAL AND SYNTHESIS METHODS, RESULTS:: objectives, data sources, study eligibility criteria, participants, and interventions, study appraisal and synthesis methods, results are not required, as the study will be a literature review. Just introduction, ethics and dissemination, and conclusion are applicable.

ETHICS AND DISSEMINATION

Ethical approval and informed consent are not required, as the study is a literature review and does not involve direct contact with patients or alterations to patient care.

CONCLUSION

AuNPs have many properties that are of great value for the diagnosis and treatment of tumors. AuNPs are small in size and can penetrate widely and deposit on the tumor site, bind to many proteins and drugs, target delivery drugs, and have good biocompatibility. The application of AuNPs in the diagnosis and treatment of tumors is very considerable. In the near future, AuNPs will certainly play an important role in the treatment of tumors.

Application of functionalized silver nanoparticles as a biochemical sensor for selective detection of lysozyme protein in milk sample

Silver nanoparticles (AgNPs) functionalized with glutamic acid (GA) was used as a biochemical sensing probe in colorimetry for detection of lysozyme protein in milk samples. The method is based on the color change of AgNPs/GA from yellow to reddish-yellow differentiated with naked eyes for qualitative determination and red shift of localized surface plasmon resonance (LSPR) absorption signal intensity of AgNPs/GA in visible region used for quantitative determination of lysozyme. The control experiments were performed to demonstrate the electrostatic force of interactions between AgNPs/GA and protein molecule. A wide linear range of 3-150 nM with limit of detection of 1.5 nM was acquired for quantitative determination of lysozyme using AgNPs/GA as a biochemical sensing probe. The advantages of using AgNPs/GA as a biochemical sensing probe are simple, label-free and economic for determination of lysozyme from milk samples.

Highly selective naked eye detection of vitamin B1 in the presence of other vitamins using graphene quantum dots capped gold nanoparticles

The application of Au-GQDs towards the sensitive determination of thiamine was demonstrated.

Plant Biomarker Recognition by Molecular Imprinting Based Localized Surface Plasmon Resonance Sensor Array: Performance Improvement by Enhanced Hotspot of Au Nanostructure

Detection of plant volatile organic compounds (VOCs) enables monitoring of pests and diseases in agriculture. We previously revealed that a localized surface plasmon resonance (LSPR) sensor coated with a molecularly imprinted sol-gel (MISG) can be used for cis-jasmone vapor detection. Although the selectivity of the LSPR sensor was enhanced by the MISG coating, its sensitivity was decreased. Here, gold nanoparticles (AuNPs) were doped in the MISG to enhance the sensitivity of the LSPR sensor through hot spot generation. The size and amount of AuNPs added to the MISG were investigated and optimized. The sensor coated with the MISG containing 20 μL of 30 nm AuNPs exhibited higher sensitivity than that of the sensors coated with other films. Furthermore, an optical multichannel sensor platform containing different channels that were bare and coated with four types of MISGs was developed to detect plant VOCs in single and binary mixtures. Linear discriminant analysis, k-nearest neighbor (KNN), and naïve Bayes classifier approaches were used to establish plant VOC identification models. The results indicated that the KNN model had good potential to identify plant VOCs quickly and efficiently (96.03%). This study demonstrated that an LSPR sensor array coated with a AuNP-embedded MISG combined with a pattern recognition approach can be used for plant VOC detection and identification. This research is expected to provide useful technologies for agricultural applications.