Correction: An amplification-free colorimetric test for sensitive DNA detection based on the capturing of gold nanoparticle clusters.

Correction for 'An amplification-free colorimetric test for sensitive DNA detection based on the capturing of gold nanoparticle clusters' by Giuseppina Tatulli, et al., Nanoscale, 2020, 12, 15604–15610, DOI: 10.1039/D0NR03517C

Micro/nanoscale patterning of nanostructured metal substrates for plasmonic applications.

The ability to precisely control the pattern of different metals at the micro- and nanoscale, along with their topology, has been demonstrated to be essential for many applications, ranging from material science to biomedical devices, electronics, and photonics. In this work, we show a novel approach, based on a combination of lithographic techniques and galvanic displacement reactions, to fabricate micro- and nanoscale patterns of different metals, with highly controlled surface roughness, onto a number of suitable substrates. We demonstrate the possibility to exploit such metal films to achieve significant fluorescence enhancement of nearby fluorophores, while maintaining accurate spatial control of the process, from submicron resolution to centimeter-sized features. These patterns may be also exploited for a wide range of applications, including SERS, solar cells, DNA microarray technology, hydrophobic/hydrophilic substrates, and magnetic devices

naked eye fingerprinting of single nucleotide polymorphisms on psoriasis patients

We report a low-cost test, based on gold nanoparticles, for the colorimetric (naked-eye) fingerprinting of a panel of single nucleotide polymorphisms (SNPs), relevant for the personalized therapy of psoriasis. Such pharmacogenomic tests are not routinely performed on psoriasis patients, due to the high cost of standard technologies. We demonstrated high sensitivity and specificity of our colorimetric test by validating it on a cohort of 30 patients, through a double-blind comparison with two state-of-the-art instrumental techniques, namely reverse dot blotting and sequencing, finding 100% agreement. This test offers high parallelization capabilities and can be easily generalized to other SNPs of clinical relevance, finding broad utility in diagnostics and pharmacogenomics

Ranking the in vivo toxicity of nanomaterials in Drosophila melanogaster

In this work, we propose a quantitative assessment of nanoparticles toxicity in vivo. We show a quantitative ranking of several types of nanoparticles (AuNPs, AgNPs, cadmium-based QDs, cadmium-free QDs, and iron oxide NPs, with different coating and/or surface chemistries), providing a categorization of their toxicity outcomes. This strategy may offer an innovative high-throughput screening tool of nanomaterials, of potential and broad interest to the nanoscience community

Microscale patterning of hydrophobic/hydrophilic surfaces by spatially controlled galvanic displacement reactions.

In this letter, we report the design and fabrication of different metal patterns for the realization of spatially controlled hydrophobic/hydrophilic regions with micrometer resolution. The fabrication procedure, based on a combination of lithographic techniques and wet-chemistry reactions (namely, spontaneous Galvanic displacement reactions) is reliable, undemanding, and highly versatile, allowing the achievement of precise spatial control along with the use of a wide variety of different materials

delivery of biologically active mir 34a in normal and cancer mammary epithelial cells by synthetic nanoparticles

Abstract Functional RNAs, such as microRNAs, are emerging as innovative tools in the treatment of aggressive and incurable cancers. In this study, we explore the potential of silica dioxide nanoparticles (SiO2NPs) in the delivery of biologically active miRNAs. Focusing on the tumor-suppressor miR-34a, we evaluated miRNAs delivery by SiO2NPs into the mammary gland, using in vitro as well as in vivo model systems. We showed that silica nanoparticles can efficiently deliver miR-34a into normal and cancer epithelial cells grown in culture without major signs of toxicity. Delivered miRNA retained the ability to silence artificial as well endogenous targets and can reduce the growth of mammospheres in 3D culture. Finally, miR-34a delivery through intra-tumor administration of SiO2NPs leads to a reduced mammary tumor growth. In conclusion, our studies suggest that silica nanoparticles can mediate the delivery of miR-34a directly into mammary tumors while preserving its molecular and biological activity

SiO2 nanoparticles biocompatibility and their potential for gene delivery and silencing

Despite the extensive use of silica nanoparticles (SiO2NPs) in many fields, the results about their potential toxicity are still controversial. In this work, we have performed a systematic in vitro study to assess the biological impact of SiO2NPs, by investigating 3 different sizes (25, 60 and 115 nm) and 2 surface charges (positive and negative) of the nanoparticles in 5 cell lines (3 in adherence and 2 in suspension). We analyzed the cellular uptake and distribution of the NPs along with their possible effects on cell viability, membrane integrity and generation of reactive oxygen species (ROS). Experimental results show that all the investigated SiO2NPs do not induce detectable cytotoxic effects (up to 2.5 nM concentration) in all cell lines, and that cellular uptake is mediated by an endocytic process strongly dependent on the particle size and independent of its original surface charge, due to protein corona effects. Once having assessed the biocompatibility of SiO2NPs, we have evaluated their potential in gene delivery, showing their ability to silence specific protein expression. The results of this work indicate that monodisperse and stable SiO2NPs are not toxic, revealing their promising potential in various biomedical applications

Conformation of microcontact-printed proteins by atomic force microscopy molecular sizing.

We investigated the structural changes occurring in proteins patterned via microcontact printing. This was done by molecular sizing using atomic force microscopy to observe the structure of printed individual metalloprotein molecules in the unlabeled and untreated states. We observed that the size of the printed proteins were more than 2-fold smaller than the native shape, which indicates that some deformations take place upon the contact-assisted adsorption on silanized silicon dioxide. This can be attributed to simultaneously occurring effects, and particularly to the sandwiching between surfaces of very different hydrophilic/hydrophobic properties during contact lithography

Gold-Nanoparticle-Based Colorimetric Discrimination of Cancer-Related Point Mutations with Picomolar Sensitivity

Point mutations in the Kirsten rat sarcoma viral oncogene homologue (KRAS) gene are being increasingly recognized as important diagnostic and prognostic markers in cancer. In this work, we describe a rapid and low-cost method for the naked-eye detection of cancer-related point mutations in KRAS based on gold nanoparticles. This simple colorimetric assay is sensitive (limit of detection in the low picomolar range), instrument-free, and employs nonstringent room temperature conditions due to a combination of DNA-conjugated gold nanoparticles, a probe design which exploits cooperative hybridization for increased binding affinity, and signal enhancement on the surface of magnetic beads. Additionally, the scheme is suitable for point-of-care applications, as it combines naked-eye detection, small sample volumes, and isothermal (PCR-free) amplification

The Effect of Irradiation Wavelength on the Quality of CdS Nanocrystals Formed Directly into PMMA Matrix

UV laser irradiation of PMMA films containing Cd thiolate precursors results in the spatially selective formation of CdS crystalline nanoparticles in the host matrix. Here we investigate the effect of the irradiation wavelength on the quality of the formed nanocrystals. Fluorescence topography and XPS studies reveal that the polymer matrix contributes to the trap states formation on the surface of the nanocrystals. When the latter are formed upon irradiation at 266 nm, they exhibit broad emission spectra, ascribed to the high degree of photodegradation of the polymer. In contrast, the irradiation at 355 nm does not chemically modify the matrix, resulting in the formation of CdS nanocrystals with narrow emission, i.e. high emission quality. This is further confirmed by fluorescence lifetime topography studies giving a mean fluorescence nanocrystal lifetime as short as 200 ps at room temperature. Thus, the optimized combination of irradiation wavelength with polymer matrix gives nanocomposite materials inco..