Academic literature on the topic 'Biomedical Application -Noble Metal Nanoparticle'

The study of the noble metal magnetic hybrid nanoparticles is a really promising topic from both the scientific and the technological points of views, with applications in several fields. Iron oxide materials which are hybridized with noble metal nanoparticles (NPs) have attracted increasing interest among researchers because of their cooperative effects on combined magnetic, electronic, photonic, and catalytic activities. This review article contains a summary of magnetic noble metal/iron oxide nanoparticle systems potentially useful in practical biomedical applications. Among the applications, engineered devices for both medical diagnosis and treatments were considered. The preparation to produce different structures, as blends or core-shell structures, of several nanometric systems was also considered. Several characterization techniques available to describe the structure, morphology and different kinds of properties of hybrid nanoparticles are also included in this review.

Nobel metal nanomaterials with interesting physical and chemical properties are ideal building blocks for engineering and tailoring nanoscale structures for specific technological applications. Bimetallic nanomaterials consisting of magnetic metals and noble metals have attracted much interest for their promising potentials in many fields including magnetic sensors, catalysts, optical detection, and biomedical applications. Particularly, effective control of the size, shape, architecture, and compositional microstructure of metal nanomaterials plays an important role in enhancing their functionality and application potentials, for example, in fuel cells, optical and biomedical sensing. This paper focuses on recent advances in controllable synthesis of bimetallic nanostructured materials. Recent contributions in controllable synthesis of bimetallic nanomaterials with different architectures including nanoparticles, nanowires, nanosheets, or nanotubes and their assemblies are presented in this paper. A wide range of facile synthesis methods are covered herein with high emphasis on wet chemical methods owing to their facility of use, efficacy, and smaller environmental footprint.

Fluorescence can be enhanced or quenched depending on the distance between the surface of a metal nanoparticle and the fluorophore molecule. Fluorescence enhancement by nearby metal particles is called metal-enhanced fluorescence (MEF). MEF shows promising potential in the field of fluorescence-based biological sensing. MEF-based biosensor systems generally fall into two platform categories: (1) a two/three-dimensional scaffold, or (2) a colloidal suspension. This review briefly summarizes the application studies using wavelength-dependent carbon dots (UV-VIS), noble metals (VIS), and upconversion nanoparticles (NIR to VIS), representative nanomaterials that contribute to the enhancement of fluorescence through the resonance energy transfer modulation and then presents a perspective on this topic.

This review focus on the effect of doping rare earth metals, transition metals, noble metals, poor metals, and non-metals on ZnO nanoparticles. ZnO is a semiconductor material with an average wide energy band gap of 3.2 eV. The doping is used to improve the properties of ZnO which strongly depend on their application. The concentration of doping, the type of doping and the process using sol-gel, hydrothermal and precipitation methods are affected in modifying the ZnO lattice parameters. The transition metal widely used for photocatalysts and sensors. The doped application of ZnO nanoparticles as a semiconductor material has proven advantageous in enabling various photocatalytic, glucose biosensors, VOC detection sensors, antibacterial, biomedical, and optoelectronic spintronic, LED, NLO, and silicon solar cells. This review provided information for scientist in choosing the synthesizing methods of ZnO with desired properties and application in future.

Monodispersive gold nanoparticles can be synthesized by a dropwise addition of a reducing agent microemulsion to a gold ion microemulsion followed by immediate stabilization with 1-decanethiol. No size-selective precipitations or digestive ripening procedures are necessary. There is no need for metal functionalization of the surfactant AOT. Gold nanoparticles with an average size of 3.8 nm and a relative size dispersion of 5.4% were observed using n-heptane as a solvent. It seems possible to adjust the nanoparticle size by small changes in the carbon chain length of the solvent. Self-assembled 2D and 3D arrays of gold nanoparticles with adjustable sizes have been obtained on carbon-coated copper grids and on a silicon wafer. The arrays have good crystallinity as evidenced by the external morphology and transmission electron diffraction results. The size of the gold nanoparticle 3D arrays depends on the immersion time and can be greater than 15 μm. This approach could be used to synthesize other noble metal nanoparticle arrays that may lead to new materials for electronic and photonic applications.

In recent years, plant-derived biomaterials, typically cellulose, acting as catalytic supports have a great impact on heterogeneous catalysis thanks to their biodegradability, non-toxicity, low-cost, availability and easy-implementation. As the most abundant biopolymer found in nature, cellulose consists of repeating cellobiose units which are built up from two anhydroglucose rings and linked by a β-1,4 glycosidic bond. The term of “nanocellulose” has been widely used to describe cellulose nano-objects, involving cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs) and bacterial cellulose (BC). Nanocellulose features high specific surface area and controllable surface chemistry, high crystalline structure, superior mechanical strength and thermal stability, resulting in its applications in food, cosmetics, pharmaceutical, biomedical and paper industries. Concerning to catalytic support application, the nanocellulose surface possesses the hydroxyl (in nature) or the sulfate ester groups (modified via acid hydrolysis), facilitating metal ions reduction towards the corresponding metal nanoparticles. In addition, the supramolecular structure of cellulose permits to disperse metal nanoparticles and prevent their agglomerations. In this context, nanocellulose is introduced as matrices for immobilizing noble metal nanoparticles and then applied to catalytic organic transformations.

Due to their good magnetic properties, excellent biocompatibility, and low price, magnetic iron oxide nanoparticles (IONPs) are the most commonly used magnetic nanomaterials and have been extensively explored in biomedical applications. Although magnetic IONPs can be used for a variety of applications in biomedicine, most practical applications require IONP-based platforms that can perform several tasks in parallel. Thus, appropriate engineering and integration of magnetic IONPs with different classes of organic and inorganic materials can produce multifunctional nanoplatforms that can perform several functions simultaneously, allowing their application in a broad spectrum of biomedical fields. This review article summarizes the fabrication of current composite nanoplatforms based on integration of magnetic IONPs with organic dyes, biomolecules (e.g., lipids, DNAs, aptamers, and antibodies), quantum dots, noble metal NPs, and stimuli-responsive polymers. We also highlight the recent technological advances achieved from such integrated multifunctional platforms and their potential use in biomedical applications, including dual-mode imaging for biomolecule detection, targeted drug delivery, photodynamic therapy, chemotherapy, and magnetic hyperthermia therapy.

Recently polymer encapsulated surface-enhanced-Raman-scattering (SERS) probes with internal noble metal core–shell structure has found growing applications in biomedical applications. Here we studied the SERS spectra of Au@Ag–4MBA@PVP (4MBA: 4-mercaptobenzoic acid; PVP: polyvinylpyrrolidone) plasmonic nanoparticles produced from a chemical reduction method. By linking the atomic force microscope (AFM) with the homebuilt confocal Raman spectrometer thus to use AFM images as guidance, we realized the measurement of the SERS spectra from separated nanoparticles. We investigated the cases for single nanoparticles and for dimer structures and report several observed results including SERS spectra linearly scaled with laser power, abrupt boosting and abnormal shape changing of SERS spectra for dimer structures. Based on the finite element method simulation, we explained the observed ratio of SERS signals between the dimer structure and the single nanoparticle, and attributed the observed abnormal spectra to the photothermal effect of these plasmonic nanoparticles. Our study provides valuable guidance for choosing appropriate laser power when applying similar SERS probes to image biological cells.

Herein, we present a facile strategy to fabricate noble metal (Ag, Au, Pd) decorated on PPy@MoS₂ microtubes. As a proof of application, the ternary PPy@MoS₂@Au hybrids reveal excellent enzyme-like catalytic performance.

The investigation of core-shell nanoparticles has been greatly exciting in biomedical applications, as this remains of prime importance in targeted drug delivery, sensing, etc. In the present work, the polarizability and scattering features of nanoparticles comprised of nano-sized dielectric/metallic core-shell structures were investigated in the fractional dimensional (FD) space, which essentially relates to the confinement of charged particles. For this purpose, three different kinds of metals—namely aluminum, gold and silver—were considered to form the shell, having a common silicon dioxide (SiO2) nanoparticle as the core. It is noteworthy that the use of noble metal-SiO2 mediums interface remains ideal to realize surface plasmon resonance. The core-shell nanoparticles were considered to have dimensions smaller than the operating wavelength. Under such conditions, the analyses of polarizability and the scattering and absorption cross-sections, and also, the extinction coefficients were taken up under Rayleigh scattering mechanism, emphasizing the effects of a varying FD parameter. Apart from these, the tuning of resonance peaks and the magnitude of surface plasmons due to FD space parameter were also analyzed. It was found that the increase of FD space parameter generally results in blue-shifts in the resonance peaks. Apart from this, the usage of gold and silver shells brings in fairly large shifts in the peak positions of wavelengths, which allows them to be more suitable for a biosensing purpose.

Tra tutti i polimeri biodegradabili conosciuti, l’acido polilattico-co-glicolico (PLGA) ha ricevuto una considerevole attenzione per le sue proprietà di biocompatibilità e biodegradabilità ed è ampiamente utilizzato come eccipiente nell’industria farmaceutica in quanto approvato dalla Food and Drug Administration (FDA) e dalla European Medicine Agency (EMA). Il filo conduttore della tesi è l’utilizzo del polimero PLGA come nano-contenitore di particelle metalliche. Nanoparticelle inorganiche sono intrappolate nella matrice polimerica di PLGA (PLGA@metallo NPs) con il conseguente vantaggio di coniugare le affascinanti proprietà dei nanomateriali metallici con l'estrema biocompatibilità del polimero, al fine di rendere le particelle inorganiche attraenti nanocostrutti per una molteplicità di applicazioni biomedicali. Il capitolo II della tesi mira allo sviluppo di un agente di contrasto (AC) per la risonanza magnetica nucleare (MRI) per la diagnosi precoce e il monitoraggio del decorso della malattia. A questo fine, la nanotecnologia offre un'opportunità unica per la progettazione di nuovi AC: la non-immunogenicità del PLGA, combinata con il comportamento paramagnetico delle particelle di manganese (MnO NPs) è capace di generare un contrasto T1-positivo nelle immagini di risonanza magnetica. Il costrutto PLGA@MnO NP è non tossico per le linee cellulari Hela e SVEC-4-10, e costituisce perciò un’attraente alternativa ai più tossici gadolinio e Teslascan. Inoltre, risultati promettenti ottenuti con MnO NPs funzionalizzate per il targeting attivo del morbo di Crohn, aprono la strada alla possibilità di coniugare l’agente di targeting anti-MadCAM-1 alla particella da noi sviluppata per una diagnosi MRI più accurata della malattia. Applicando la metodica di incapsulamento di MnO NPs a particelle diverse per materiale, forma e dimensione, è stato messo a punto un protocollo universale di internalizzazione di particelle inorganiche in particelle di PLGA. Il metodo descritto è stato realizzato in collaborazione con il gruppo del professor Luis Liz-Marzan presso il CICBiomaGune, San Sebastian (Spagna). Il capitolo III è focalizzato sul caricamento di particelle di oro, ferro e Cd/Se nella matrice di PLGA. Per avere una miglior efficienza di incapsulamento è necessari avere particelle metalliche altamente concentrate e stabili in fase organiche. A tal fine sono stati sviluppati due approcci differenti per il trasferimento in solvente organico di particelle a base di oro: il metodo monobasico e bifasico. Entrambe le procedure sono traslabili a particelle di qualsiasi dimensione e forma. I protocolli sviluppati mostrano strategie interessanti per la fabbricazione di nanostrutture ibride che uniscono i vantaggi della biodegradabilità ed elevata biocompatibilità del PLGA con le proprietà uniche delle nanoparticelle inorganiche, per ottenere nanosistemi adatti per numerose applicazioni in campo medico. Ad esempio, particelle d'oro plasmoniche in PLGA NPs possono essere impiegate per la terapia fototermica e la diagnosi; particelle di ossido di ferro intrappolate nel polimero potrebbero operare come agenti per ipertermia o diagnosi MRI; particelle di ossido di manganese caricate in PLGA NP hanno di dimostrato ottime proprietà come AC. Prospettive future prevedono la funzionalizzazione dei nanocostrutti preparati per implementare la loro efficacia come agenti teranostici.
Above all biodegradable polymers, poly(lactide-co-glycolide acid) (PLGA) has received a considerable attention as excipientin pharmaceutical industry up to be approved by Food and Drug Administration (FDA) and European Medicine Agency (EMA). The main features of PLGA have been discussed in chapter I. The headline of this work is the application of PLGA polymer as nano-container for metal nanoparticles: inorganic-based NPs (PLGA@metalNPs) entrapped into PLGA nano-containers harness the fascinating properties of the metallic nanomaterials with the extreme biocompatibility of the polymer, to makeinorganic particlesvery attractive tools for future biomedical applications. The thesis focuses on two main tasks: to prepare PLGA@MnO nanocomposite for targeted imaging of Crohn’s disease, and to set up and generalize the gold NPs phase transfer procedure and the PLGA@metal NPs synthetic protocol. Chapter II concerns the development of a manganese-based contrast agent (CA) for MRI application in vivo to achieve a highly accurate diagnosis of the stadiation and follow-up of the disease. In this respect, nanomedicine offers a unique opportunity to design novel smart enhancers by combining the safety of PLGA polymer andthe paramagnetic behavior of manganese, to generate PLGA@MnO nanocomposites as promising T1-positivecontrast agent for MRI. PLGA@MnO NPsare safe for Hela and SVEC-4-10 cell lines and thus they are more attractive contrast agents compared to gadolinium and Teslascan, which are more toxic. In addition, the promising results obtained with biofunctionalized MnO NPs for the active targeting of Crohn’s disease have also suggested to conjugate PLGA@MnO NPs with anti-MAdCAM-1 to target mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) overexpressed in inflamed bowel sites to enhance further the spatial resolution of MR images in vivo. In view of the encapsulation of manganese-based particles, a general method to entrap inorganic nanoparticles in the PLGA matrix was investigated further through Chapter III. The method here discussed has been set up in collaboration with the Luis Liz-Marzan’s group at CICBiomaGune (Spain). The PLGA polymer has been exploited to trap metal NPs of different nature to make them safe for the human organismand at the same time to maintaintheir fascinating chemical-physical properties. PLGA NPs loading gold nanoparticles (spheres, rods and cages), iron oxide and quantum dots have been synthesized by single emulsion methodand characterized by Dynamic Light scattering and Transmission Electron Microscopy. Efficient encapsulation has been obtained by highly concentrated and stable metal NPs in organic solvent.To this purpose, two different approaches, the biphasic and the monophasic one, have been explored to transfer gold nanoparticles to organic solvent (iron and manganese-based NPs already meet these conditions). Both the procedures have been adapted to any size and shape of gold NPs. These general approaches are attractive strategies toward the fabrication of heterogeneous nanostructures based on inorganic platforms and functional cargo molecules (e.g. drugs, vaccines, nucleic acids, quantum dots, magnetic nanoparticles) located within the hydrophobic spacer. The hybrid particles join the advantages of the biodegradability and the high biocompatibility of PLGA polymer with the unique properties of inorganic nanoparticles, to obtain potential systems for numerous biomedical applications. PLGA loading plasmonic gold particles could be employed for phototermal therapy and diagnosis; iron oxide particles entrapped in the polymer NPs could act as hypertermic therapeutic agent or MRI contrast enhancers; manganese oxide nanoparticle-loaded PLGA NPs have been demonstrated to be a high performing CA. Future perspectives will be focused on the application of PLGA@inorganic NPs and their functionalizing particles with targeting moieties to enhance also their efficacy as theranostic agents.

Les nanoparticules d’or (Au NPs) ont montré des résultats prometteurs en nanomédecine appliquée à la cancérologie. Elles sont capables de s’accumuler dans les zones tumorales, d’induire un effet thérapeutique en délivrant des principes actifs ou un effet photo/radiothérapeutique grâce à leurs propriétés d’absorption d’énergie. Elles permettent aussi le diagnostic par différentes techniques d’imagerie. Cette double activité les définit comme des agents théranostics. Les nanoclusters d’or (Au NCs) forment une sous-famille intéressante de Au NPs. Ils sont composés d’une dizaine à une centaine d’atomes d’or stabilisés par des molécules organiques. Leur taille inférieure à ~8 nm leur permet d’être éliminé par les reins et d’avoir des propriétés de photoluminescence (PL) jusque dans l’infrarouge, une fenêtre spectrale adaptée à l’imagerie optique in vivo. Ils peuvent aussi induire la mort cellulaire sous irradiation en raison des propriétés intrinsèques de l’or. Leurs propriétés optiques, de circulation sanguine et d’accumulation tumorale sont sensibles à de faibles modifications de la taille des Au NCs et de leur chimie de surface. Actuellement, les résultats précliniques sont encore insuffisants pour espérer un transfert en clinique et il est nécessaire d’améliorer la caractérisation des Au NCs et d’étudier leur comportement in vitro et in vivo.Dans ce contexte, mon projet de thèse a consisté à fonctionnaliser ces Au NCs pour améliorer leur accumulation tumorale. La première stratégie repose sur l’auto-agrégation des Au NCs dans le microenvironnement tumoral. Pour cela la surface des Au NCs a été soit i) fonctionnalisée avec des molécules chimiques favorisant des réactions de chimie click bioorthogonale, soit ii) fonctionnalisée avec des monobrins d’oligonucléotides complémentaires pouvant s’hybrider. L’auto-agrégation des Au NCs en solution a confirmée l’augmentation de la PL par transfert d’énergie inter-particules. Cette propriété pourrait éventuellement améliorer l’effet thérapeutique, mais ils doivent encore être caractérisés in vivo. La seconde stratégie a consisté à augmenter l’affinité des Au NCs pour les cellules en ajoutant de l’arginine à la surface des Au NCs de façon contrôlée. En effet, l’arginine est connue pour favoriser l’interaction électrostatique avec les membranes plasmiques et l’internalisation cellulaire. Nous avons déterminé le seuil maximum d’arginine par Au NCs permettant d’augmenter la PL tout en conservant leur petite taille. Les meilleurs candidats ont une forte capacité d’interaction électrostatique avec des membranes artificielles même en présence de sérum, suggérant que l’opsonisation des Au NCs est faible. Leurs capacités d’interaction (< 5min) et d’internalisation (<30 min) sont rapides et ont été confirmées sur des cellules humaines de mélanome in vitro, sans toxicité notable. Cependant d’après une étude sur des sphéroïdes irradiés, l’ajout d’arginines aurait un effet « de pirégeage » sur la production d’espèces réactives oxygénées diminuant le pouvoir radiosensibilisant des Au NCs. La présence de charges positives sur les Au NCs contenant des arginines et leur capacité d’internalisation permettent aussi de les utiliser in vitro pour vectoriser des polymères anioniques tels que des siRNA. En revanche, ces Au NCs administrés par voie intraveineuse chez des souris porteuses de tumeurs sont tous éliminés extrêmement rapidement par voie rénale ce qui ne leur permet pas de s’accumuler suffisamment dans les tumeurs. Ces travaux démontrent donc que la fonctionnalisation des Au NCs influence fortement leurs propriétés optiques et physico-chimiques, leurs interactions avec les cellules et leurs effets théranostics. Il serait intéressant d’appliquer ces stratégies sur des Au NCs circulants plus longtemps dans le sang pour démontrer l’effet de ces fonctionnalisations sur l’accumulation tumorale
Gold nanoparticles (Au NPs) have shown promising results in nanomedicine applied to oncology. They are capable of accumulating in tumor areas, inducing a therapeutic effect by delivering drugs or a photo-/radiotherapeutic effect thanks to their energy absorption properties. They also allow diagnosis by different imaging techniques. This dual activity defines them as theranostic agents. Gold nanoclusters (Au NCs) define an interesting sub-family of Au NPs. They are composed of about ten to hundred gold atoms stabilized by organic molecules. Their size smaller than ~8 nm allows them to be eliminated by the kidneys and to exhibit photoluminescence (PL) properties until infrared wavelengths, which are suitable for in vivo optical imaging. They can also induce cell death under irradiation due to the intrinsic properties of gold. Their optical features, pharmaco-kinetic and tumor accumulation are highly sensitive to size and surface chemistry modification. Currently, preclinical results are not sufficient for clinical transfer and it is necessary to improve the characterization of Au NCs and to study their behaviour in vitro and in vivo.In this context, my thesis project focused on the functionalization of Au NCs in order to improve their accumulation in tumors. The first strategy is based on the self-aggregation of Au NCs in the tumor microenvironment. For this purpose, the surface of the Au NCs was either functionalized with i) molecules promoting bioorthogonal click chemistry reactions, or ii) complementary oligonucleotides that can hybridize. The self-aggregation of Au NCs in solution confirmed the increase in PL by inter-particle energy transfer. The self-agregation of Au NCs could potentially improve the therapeutic effect, but the Au NCs still need to be characterized in vivo. The second strategy consisted in increasing the affinity of Au NCs for cells by adding controlled amounts of arginine on their surface. Indeed, arginine is known to promote electrostatic interaction with plasma membranes and cellular internalization. We have determined the maximum arginine threshold per Au NCs, allowing to increase the PL while keeping their small size with high colloidal stability. The best candidates have a high capacity for electrostatic interaction with artificial membranes even in the presence of serum, suggesting that the opsonization of Au NCs is low. Their interaction (< 5min) and internalization (<30 min) capacities are rapid, and have been confirmed on human melanoma cells in vitro, without significant toxicity. However, according to a study on irradiated spheroids performed in our team, the addition of arginines would have a "trapping" effect on the production of reactive oxygen species, reducing the radiosensitizing power of Au NCs. The presence of positive charges on Au NCs containing arginines and their internalization capacity also can serve in vitro to deliver anionic polymers and biomolecules such as siRNA. However, these Au NCs administered intravenously to tumor-bearing mice are eliminated extremely rapidly by the kidneys, thus reducing their ability to accumulate in tumors. This work showed that the functionalization of Au NCs strongly influences their optical and physicochemical properties, their interactions with cells and their theranostic effects. It would be interesting to apply these strategies to Au NCs circulating longer in the blood to demonstrate the effect of these functionalizations on tumor diagnostics and therapy

碩士
國防大學理工學院
化學工程碩士班
102
In this study, the preparation of St-co-MPS copolymer with both styrene(St) monomer and γ-methacryloxypropyltrimethoxysilane (γ-MPS) monomer by free radical polymerization. Poly(St-co-MPS)/Pd was prepared via self-reduction of palladium ions by St-co-MPS oligomer without using any reducing agent or surfactant. It was shown that Pd was reduced by the chain-end sulfate groups of styrene when copolymer reacted with the metallic ions. These St-co-MPS copolymer was characterized by 13C-NMR, 29Si-NMR and FTIR to confirm polymer composition and quantity sulfonation, and those self-assembly polymer-metal nanocomposites were characterized by electron microscopy (TEM), observe the stability of LU Misizer(LUM). The Poly(St-co-MPS)/Pd used as ink for catalytic pattern of glasses, which allows to from the metallic pattern by electroless deposition. The cross-linking extend of Poly(St-co-MPS)/Pd ink and glasses dipping with different pH condition was characterized by X-ray photoelectron spectroscope(XPS) to enhance the adhesion of the Poly(St-co-MPS)/Pd ink and glass substrate. The pattern thickness of Ni layer about 8.51 μm. Finally, we used Inkjet printing metallization process has been used in the fabricated of mobile antenna on special glass case, The WWAN five band antenna was made on the new glass case substrate by the printing of the catalyst activation and electroless plating forming the metal pattern. It will simplify the institutions of the antenna, and resolve the configuration problems of the limited space in the mobile phone's.

The advent of molecular biology and biotechnology has given ease and comfort for the screening and detection of different animal diseases caused by bacterial, viral, and fungal pathogens. Furthermore, detection of antibiotics and its residues has advanced in recent years. However, most of the process of animal disease diagnostics is still confined in the laboratory. The next step to conduct surveillance and prevent the spread of animal infectious diseases is to detect these diseases in the field. Through the discovery and continuous development in the field of nanobiotechnology, it was found that incorporation of noble metal nanoparticles to biotechnology tools such as the loop-mediated isothermal amplification (LAMP), lateral flow assays (LFAs) and dipsticks provided a promising start to conduct point-of-care diagnostics. Moreover, the modification and application of nanoparticle noble metals has increased the stability, effectiveness, sensitivity and overall efficacy of these diagnostic tools. Thus, recent advances in disease diagnostics used these noble metals such as gold, silver and platinum.

Adsorption is widely acknowledged as one of the best options that are available for the removal of contaminants from water. Contamination of water does not only create water scarcity, but it has the capacity to generate and transfer several environmental problems including threat to public health. This chapter reviewed calcium oxide nanoparticle (CaONP) as a noble metal oxide for the removal of contaminants from water. The review is concentrated in the general overview of water contamination, metal oxide nanoparticles, general application of CaONP, synthetic methods, characterization method, and applications. The chapter observed that little is done on the use of CaONP for the removal of contaminants from water except for dyes, some heavy metal ions, and few organic/inorganic compounds. It is also observed that CaONP can be applied as adsorbent and in photocatalytic degradation of dye. Suggestions are made on the possibility of utilizing local raw materials that are easily accessible, cheap, and environmental sources of raw materials for the synthesis of CaONP.

Graphene quantum dots (GQDs) are famously known for large surface area, good dispersibility, good conductivity, and high transparency with good photochemical, electrochemical, and optical properties that are utilized in many biomedical and biotechnological applications. Interestingly, GQDs were reported to serve as an excellent reducing reagent in the synthesis of noble metal nanoparticles such as silver nanoparticles (AgNPs). Moreover, GQDs eradicate the limitation of impurities of AgNPs synthesized using plant extracts as a stabilizer and reducing agents. Therefore, we experimented GQDs synthesis from moringa oleifera (MO) plant extracts compared to citric and urea synthesized GQDs. And used the synthesized GQDs to synthesize, reduce and functionalize AgNPs. MO contains about 110 compounds, high nutrients, vitamins, oleic oil, and phytoconstituents such as alkaloids, flavonoids, glucosinolates, saponins, tannins, terpenes, steroids, phenolic acids, which suggested to us that, MO extracts can serve as a capping agent in the synthesis of nanoparticles. Initially, MO leaves and seeds water phase extracts were obtained by overnight distillation and lyophilized to create a stock solution of 1mg/ml. Next, following Das, R. et al and slightly modifying the followed method by varying the MO extract concentration from 20µL to 60 µL, AgNPs were synthesized by hydrothermal method. GQDs were separately synthesized adopting Tran, H.V. et al method and later added to the AgNPs forming a more stable hybrid structure that was characterized using the UV-vis spectroscopy (UV-Vis), Nano zeta sizer, Raman spectroscopy, and the Fourier Infrared transmission resonance (FTIR). As the concentration of MO extract increased, the color change intensity increased symbolizing the formation of AgNPs while the luminous bright solutions under the UV light symbolized the formation of GQDs. This study lay the foundation for further research and analysis to be done on the nanozyme or biosensor application of enhanced functionalized and stable hybrid AgNPs with GQDs.

Current efforts in medical diagnostic technology focus toward developing biological sensors with the capacity for detecting trace quantities of specified organic molecules. In this study, metallic nanoparticles were investigated for the development of field-enhanced chemical and biological detection devices with the capacity to achieve single-molecule level detection resulting from surface enhanced Raman scattering (SERS) associated with closely spaced noble metal nanostructures.[1, 2] Localized surface plasmon resonance (LSPR) sensors likewise benefit from the incorporation of ordered metal nanoparticles on surfaces, providing increased shift in minimum of reflectivity with biological binding event (figure 1).[3]