Application of Polypodiopsida Class in Nanotechnology-Potential towards Development of More Effective Bioactive Solutions

The area of phytosynthesized nanomaterials is rapidly developing, with numerous studies being published yearly. The use of plant extracts is an alternative method to reduce the toxic potential of the nanomaterials and the interest in obtaining phytosynthesized nanoparticles is usually directed towards accessible and common plant species, ferns not being explored to their real potential in this field. The developed nanoparticles could benefit from their superior antimicrobial and antioxidant properties (compared with the nanoparticles obtained by other routes), thus proposing an important alternative against health care-associated and drug-resistant infections, as well as in other types of applications. The present review aims to summarize the explored application of ferns in nanotechnology and related areas, as well as the current bottlenecks and future perspectives, as emerging from the literature data.

Eco-Friendly Nanoplatforms for Crop Quality Control, Protection, and Nutrition

Agricultural chemicals have been widely utilized to manage pests, weeds, and plant pathogens for maximizing crop yields. However, the excessive use of these organic substances to compensate their instability in the environment has caused severe environmental consequences, threatened human health, and consumed enormous economic costs. In order to improve the utilization efficiency of these agricultural chemicals, one strategy that attracted researchers is to design novel eco-friendly nanoplatforms. To date, numerous advanced nanoplatforms with functional components have been applied in the agricultural field, such as silica-based materials for pesticides delivery, metal/metal oxide nanoparticles for pesticides/mycotoxins detection, and carbon nanoparticles for fertilizers delivery. In this review, the synthesis, applications, and mechanisms of recent eco-friendly nanoplatforms in the agricultural field, including pesticides and mycotoxins on-site detection, phytopathogen inactivation, pest control, and crops growth regulation for guaranteeing food security, enhancing the utilization efficiency of agricultural chemicals and increasing crop yields are highlighted. The review also stimulates new thinking for improving the existing agricultural technologies, protecting crops from biotic and abiotic stress, alleviating the global food crisis, and ensuring food security. In addition, the challenges to overcome the constrained applications of functional nanoplatforms in the agricultural field are also discussed.

Trends in Nanotechnology for in vivo Cancer Diagnosis: Products and Patents

BACKGROUND

Cancer is a set of diseases formed by abnormal growth of cells leading to the formation of the tumor. The diagnosis can be made through symptoms' evaluation or imaging tests, however, the techniques are limited and the tumor detection may be late. Thus, pharmaceutical nanotechnology has emerged to optimize the cancer diagnosis through nanostructured contrast agent's development.

OBJECTIVE

This review aims to identify commercialized nanomedicines and patents for cancer diagnosis.

METHODS

The databases used for scientific articles research were Pubmed, Science Direct, Scielo and Lilacs. Research on companies' websites and articles for the recognition of commercial nanomedicines was performed. The Derwent tool was applied for patent research.

RESULTS

This article aimed to research on nanosystems based on nanoparticles, dendrimers, liposomes, composites and quantum dots, associated to imaging techniques. Commercialized products based on metal and composite nanoparticles, associated with magnetic resonance and computed tomography, have been observed. The research conducted through Derwent tool displayed a small number of patents using nanotechnology for cancer diagnosis. Among these patents, the most significant number was related to the use of systems based on metal nanoparticles, composites and quantum dots.

CONCLUSION

Although few systems are found in the market and patented, nanotechnology appears as a promising field for the development of new nanosystems in order to optimize and accelerate the cancer diagnosis.

What do we actually see in intracellular SERS? Investigating nanosensor-induced variation

Plasmonic nanoparticles (NPs), predominantly gold (AuNPs), are easily internalised into cells and commonly employed as nanosensors for reporter-based and reporter-free intracellular SERS applications. While AuNPs are generally considered non-toxic to cells, many biological and toxicity studies report that exposure to NPs induces cell stress through the generation of reactive oxygen species (ROS) and the upregulated transcription of pro-inflammatory genes, which can result in severe genotoxicity and apoptosis. Despite this, the extent to which normal cellular metabolism is affected by AuNP internalisation remains a relative unknown along with the contribution of the uptake itself to the SERS spectra obtained from within so called 'healthy' cells, as indicated by traditional viability tests. This work aims to interrogate the perturbation created by treatment with AuNPs under different conditions and the corresponding effect on the SERS spectra obtained. We characterise the changes induced by varying AuNP concentrations and medium serum compositions using biochemical assays and correlate them to the corresponding intracellular reporter-free SERS spectra. The different serum conditions lead to different extents of nanoparticle internalisation. We observe that changes in SERS spectra are correlated to an increasing amount of internalisation, confirmed qualitatively and quantitatively by confocal imaging and ICP-MS analysis, respectively. We analyse spectra and characterise changes that can be attributed to nanoparticle induced changes. Thus, our study highlights a need for understanding condition-dependent NP-cell interactions and standardisation of nanoparticle treatments in order to establish the validity of intracellular SERS experiments for use in all arising applications.

Stable DHLA–PEG capped PbS quantum dots: from synthesis to near-infrared biomedical imaging

Stability, biocompatibility and near-infrared photoluminescence of PbS nanocrystals capped with PEG-based ligands open up realistic prospects for non-invasive bioimaging applications.

Gold Triangular Nanoprisms and Nanodecahedra: Synthesis and Interaction Studies with Luminol toward Biosensor Applications

Gold triangular nanoprisms and nanodecahedra (pentagonal bipyramids) were synthesized in the absence and presence of nanoseeds by a simple solvothermal synthesis through the reduction of Auric Chloride (HAuCl₄) with poly(vinylpyrrolidone) (PVP) in N,N-dimethylformamide (DMF), respectively. These gold nanoparticles exhibit two plasmon resonance bands. The interaction of these gold nanoparticles with luminol was investigated using UV-vis and fluorescence spectroscopy since hefty number of environmental and biological sensors are based on the combination of luminol and gold nanoparticles. The gold nanoparticles quenches the fluorescence of luminol through a static quenching mechanism, i.e., ground state complex formation, which was confirmed by both absorption spectroscopy as well as time-resolved fluorescence spectroscopy. The Stern-Volmer quenching constant and the effective quenching constant determine that gold nanodecahedra has more interaction with luminol than that of triangular gold nanoprisms. The distance between the gold nanoparticles and luminol, calculated using FRET theory, is less than 8 nm, which indicates efficient energy transfer during interaction. These results are expected to be useful for the development of novel sensors.

Nanoparticles and intracellular applications of surface-enhanced Raman spectroscopy

Surface-enhanced Raman spectrocopy (SERS) offers ultrasensitive vibrational fingerprinting at the nanoscale. Its non-destructive nature affords an ideal tool for interrogation of the intracellular environment, detecting the localisation of biomolecules, delivery and monitoring of therapeutics and for characterisation of complex cellular processes at the molecular level. Innovations in nanotechnology have produced a wide selection of novel, purpose-built plasmonic nanostructures capable of high SERS enhancement for intracellular probing while microfluidic technologies are being utilised to reproducibly synthesise nanoparticle (NP) probes at large scale and in high throughput. Sophisticated multivariate analysis techniques unlock the wealth of previously unattainable biomolecular information contained within large and multidimensional SERS datasets. Thus, with suitable combination of experimental techniques and analytics, SERS boasts enormous potential for cell based assays and to expand our understanding of the intracellular environment. In this review we trace the pathway to utilisation of nanomaterials for intracellular SERS. Thus we review and assess nanoparticle synthesis methods, their toxicity and cell interactions before presenting significant developments in intracellular SERS methodologies and how identified challenges can be addressed.

Surface Charge Controls the Suborgan Biodistributions of Gold Nanoparticles

Surface chemistry plays a deciding role in nanoparticle biodistribution, yet very little is known about how surface chemistry influences the suborgan distributions of nanomaterials. Here, using quantitative imaging based on laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), we demonstrate that surface charge dictates the suborgan distributions of nanoparticles in the kidney, liver, and spleen of mice intravenously injected with functionalized gold nanoparticles. Images of the kidney show that positively charged nanoparticles accumulate extensively in the glomeruli, the initial stage in filtering for the nephron, suggesting that these nanoparticles may be filtered by the kidney at a different rate than the neutral or negatively charged nanoparticles. We find that positively and negatively charged nanoparticles accumulate extensively in the red pulp of the spleen. In contrast, uncharged nanoparticles accumulate in the white pulp and marginal zone of the spleen to a greater extent than the positively or negatively charged nanoparticles. Moreover, these uncharged nanoparticles are also more likely to be found associated with Kupffer cells in the liver. Positively charged nanoparticles accumulate extensively in liver hepatocytes, whereas negatively charged nanoparticles show a broader distribution in the liver. Together these observations suggest that neutral nanoparticles having 2 nm cores may interact with the immune system to a greater extent than charged nanoparticles, highlighting the value of determining the suborgan distributions of nanomaterials for delivery and imaging applications.

Characterization and Visualization of Vesicles in the Endo-Lysosomal Pathway with Surface-Enhanced Raman Spectroscopy and Chemometrics

Surface-enhanced Raman spectroscopy (SERS) is an ultrasensitive vibrational fingerprinting technique widely used in analytical and biosensing applications. For intracellular sensing, typically gold nanoparticles (AuNPs) are employed as transducers to enhance the otherwise weak Raman spectroscopy signals. Thus, the signature patterns of the molecular nanoenvironment around intracellular unlabeled AuNPs can be monitored in a reporter-free manner by SERS. The challenge of selectively identifying molecular changes resulting from cellular processes in large and multidimensional data sets and the lack of simple tools for extracting this information has resulted in limited characterization of fundamental cellular processes by SERS. Here, this shortcoming in analysis of SERS data sets is tackled by developing a suitable methodology of reference-based PCA-LDA (principal component analysis-linear discriminant analysis). This method is validated and exemplarily used to extract spectral features characteristic of the endocytic compartment inside cells. The voluntary uptake through vesicular endocytosis is widely used for the internalization of AuNPs into cells, but the characterization of the individual stages of this pathway has not been carried out. Herein, we use reporter-free SERS to identify and visualize the stages of endocytosis of AuNPs in cells and map the molecular changes via the adaptation and advantageous use of chemometric methods in combination with tailored sample preparation. Thus, our study demonstrates the capabilities of reporter-free SERS for intracellular analysis and its ability to provide a way of characterizing intracellular composition. The developed analytical approach is generic and enables the application of reporter-free SERS to identify unknown components in different biological matrices and materials.

Layered Metal Nanoparticle Structures on Electrodes for Sensing, Switchable Controlled Uptake/Release, and Photo-electrochemical Applications

Layered metal nanoparticle (NP) assemblies provide highly porous and conductive composites of unique electrical and optical (plasmonic) properties. Two methods to construct layered metal NP matrices are described, and these include the layer-by-layer deposition of NPs, or the electropolymerization of monolayer-functionalized NPs, specifically thioaniline-modified metal NPs. The layered NP composites are used as sensing matrices through the use of electrochemistry or surface plasmon resonance (SPR) as transduction signals. The crosslinking of the metal NP composites with molecular receptors, or the imprinting of molecular recognition sites into the electropolymerized NP matrices lead to selective and chiroselective sensing interfaces. Furthermore, the electrosynthesis of redox-active, imprinted, bis-aniline bridged Au NP composites yields electrochemically triggered "sponges" for the switchable uptake and release of electron-acceptor substrates, and results in conductive surfaces of electrochemically controlled wettability. Also, photosensitizer-relay-crosslinked Au NP composites, or electrochemically polymerized layered semiconductor quantum dot/metal NP matrices on electrodes, are demonstrated as functional nanostructures for photoelectrochemical applications.

Review: Application of Nanoparticles in Urothelial Cancer of the Urinary Bladder

Bladder cancer is a common malignancy of the urinary tract, which generally develops in the epithelial lining of the urinary bladder. The specific course of treatment depends on the stage of bladder cancer; however, therapeutic strategies typically involve intravesical drug delivery to reduce toxicity and increase therapeutic effects. Recently, metallic, polymeric, lipid, and protein nanoparticles have been introduced to aid in the treatment of bladder cancer. Nanoparticles are also commonly used as pharmaceutical carriers to improve interactions between drugs and the urothelium. In this review, we classify the characteristics of bladder cancer and discuss the types of nanoparticles used in various treatment modalities. Finally we summarize the potential applications and benefits of various nanoparticles in intravesical therapy.

Raman Characterization of Nanoparticle Transport in Microfluidic Paper-Based Analytical Devices (μPADs)

There is great interest in the use of microfluidic paper-based analytical devices (μPADs) for low-cost diagnostics. In this contribution, we illustrate the utility of Raman spectral imaging for both μPAD characterization and for quantification of the transport of applied reagents and analytes within these devices. We evaluated the transport of nanoscale particles within μPADs using a suite of differentially functionalized gold (AuNP) and silver (AgNP) nanoparticles with diameters of 8-64 nm. Nanoparticle transport within the cellulose matrix was characterized by collection of both Raman and surface-enhanced Raman spectroscopy (SERS) spectral maps that enabled differentiation of cellulose fibers and characterization of analyte deposition patterns. The transport of citrate (cit), BSA, PEG, PVP, and DNA functionalized AuNP and AgNP in wax-printed μPADs was primarily affected by nanoparticle surface chemistry rather than particle size or core composition. Sample pH (3-10) influenced the transport of 15 nm BSA-cit-AuNP, but not 15 nm cit-AuNP, because of the effects of solution pH on the charge and conformation of BSA. Derjaguin, Landau, Verwey, and Overbeek theory (DLVO) and extended DLVO (xDLVO) theory are used to explain the collected experimental results.

Identification of intracellular gold nanoparticles using surface-enhanced Raman scattering

The identification of intracellular distributions of noble metal nanoparticles is of great utility for many biomedical applications. We present an effective method to distinguish intracellular from extracellular nanoparticles by selectively quenching the SERS signals from dye molecules adsorbed onto star-shaped gold nanoparticles that have not been internalized by cells.

Nano-imaging enabled via self-assembly

Imaging object details with length scales below approximately 200 nm has been historically difficult for conventional microscope objective lenses because of their inability to resolve features smaller than one-half the optical wavelength. Here we review some of the recent approaches to surpass this limit by harnessing self-assembly as a fabrication mechanism. Self-assembly can be used to form individual nano- and micro-lenses, as well as to form extended arrays of such lenses. These lenses have been shown to enable imaging with resolutions as small as 50 nm half-pitch using visible light, which is well below the Abbe diffraction limit. Furthermore, self-assembled nano-lenses can be used to boost contrast and signal levels from small nano-particles, enabling them to be detected relative to background noise. Finally, alternative nano-imaging applications of self-assembly are discussed, including three-dimensional imaging, enhanced coupling from light-emitting diodes, and the fabrication of contrast agents such as quantum dots and nanoparticles.

Techniques for physicochemical characterization of nanomaterials

Advances in nanotechnology have opened up a new era of diagnosis, prevention and treatment of diseases and traumatic injuries. Nanomaterials, including those with potential for clinical applications, possess novel physicochemical properties that have an impact on their physiological interactions, from the molecular level to the systemic level. There is a lack of standardized methodologies or regulatory protocols for detection or characterization of nanomaterials. This review summarizes the techniques that are commonly used to study the size, shape, surface properties, composition, purity and stability of nanomaterials, along with their advantages and disadvantages. At present there are no FDA guidelines that have been developed specifically for nanomaterial based formulations for diagnostic or therapeutic use. There is an urgent need for standardized protocols and procedures for the characterization of nanoparticles, especially those that are intended for use as theranostics.

One-step synthesis of platinum nanoparticles loaded in alginate bubbles

Composite particles with multifunctions have been extensively utilized for various applications. Bubble particles can be applied for ultrasound-mediated imaging, drug delivery, absorbers, cell culture, etc. This study proposes a one-step strategy to obtain Pt nanoparticles loaded in alginate bubbles. A needle-based droplet formation was used to generate uniform alginate particles about 2 mm in diameter. The hydrolysis reaction of NaBH4 was utilized to produce gaseous hydrogen and then trapped within alginate particles to form bubbles. The Pt(4+) mixed with alginate solution was dropped into the reservoir to react with reducing NaBH4 and hardening CaCl2 to form Pt nanoparticles-alginate composite bubbles. Results indicate that the size of bubbles decreases with the CaCl2 concentration (1% ~ 20%), and size of bubbles increases with the NaBH4 concentration (1 ~ 20 mM). The advantages for the present approach include low cost, easy operation, and effective production of Pt nanoparticles-alginate composite bubbles.

Antibody-drug gold nanoantennas with Raman spectroscopic fingerprints for in vivo tumour theranostics

Inspired by the ability of SERS nanoantennas to provide an integrated platform to enhance disease targeting in vivo, we developed a highly sensitive probe for in vivo tumour recognition with the capacity to target specific cancer biomarkers such as epidermal growth factor receptors (EGFR) on human cancer cells and xenograft tumour models. Here, we used ~90nm gold nanoparticles capped by a Raman reporter, encapsulated and entrapped by larger polymers and a FDA antibody-drug conjugate - Cetuximab (Erbitux®) - that specifically targets EGFR and turns off a main signalling cascade for cancer cells to proliferate and survive. These drug/SERS gold nanoantennas present a high Raman signal both in cancer cells and in mice bearing xenograft tumours. Moreover, the Raman detection signal is accomplished simultaneously by extensive tumour growth inhibition in mice, making these gold nanoantennas ideal for cancer nanotheranostics, i.e. tumour detection and tumour cell inhibition at the same time.

Nanoparticle attachment on Ag nanorings and nanoantenna for large increases of surface-enhanced Raman scattering

A simple and inexpensive approach based on the heat-treatment of Ag⁺/PVA/PVP composite film on quartz glass has been developed for fabricating large-area Ag nanorings attached small nanoparticles.

Seeing through bone with surface-enhanced spatially offset Raman spectroscopy

Surface-enhanced spatially offset Raman spectroscopy (SESORS) is a label-free vibrational spectroscopy that has the potential for in vivo imaging. Previous SESORS experiments have been limited to acquiring spectra using SERS substrates implanted under the skin or from nanoparticles embedded in tissue. Here we present SESORS measurements of SERS active nanoparticles coated with a Raman reporter molecule (nanotags) acquired, for the first time, through bone. We demonstrate the ability of SESORS to measure spectra through various thicknesses (3-8 mm) of bone. We also show that diluted nanotag samples (~2 × 10(12) particles) can be detected through the bone. We apply a least-squares support vector machine analysis to demonstrate quantitative detection. It is anticipated that these through-bone SESORS measurements will enable real-time, non-invasive spectroscopic measurement of neurochemicals through the skull, as well as other biomedical applications.