Uncoated gold nanoparticles create fewer and less localized defects in model prokaryotic than in model eukaryotic lipid membranes.

The rise of the populations of antibiotic resistant bacteria represents an increasing threat to human health. In addition to the synthesis of new antibiotics, which is an extremely expensive and time-consuming process, one of the ways to combat bacterial infections is the use of gold nanoparticles (Au NPs) as the vehicles for targeted delivery of therapeutic drugs. Since such a strategy requires the investigation of the effect of Au NPs (with and without drugs) on both bacterial and human cells, we investigated how the presence of coating-free Au NPs affects the physicochemical properties of lipid membranes that model prokaryotic (PRO) and eukaryotic (EU) cells.

Plasmon-enhanced photocatalysis: New horizons in carbon dioxide reduction technologies.

The urgent need for transition to renewable energy is underscored by a nearly 50 % increase in atmospheric carbon dioxide levels over the past century. The combustion of fossil fuels for energy production, transportation, and industrial activities are the main contributors to carbon dioxide emissions in the anthroposphere. Present approaches to reducing carbon emissions are proving inefficient, thereby accentuating the relevance of carbon dioxide photocatalysis in combating climate change - one of the critical issues of public concern.

A Novel Optical Fiber Terahertz Biosensor Based on Anti-Resonance for The Rapid and Nondestructive Detection of Tumor Cells.

The sensitive and accurate detection of tumor cells is essential for successful cancer therapy and improving cancer survival rates. However, current tumor cell detection technologies have some limitations for clinical applications due to their complexity, low specificity, and high cost. Herein, we describe the design of a terahertz anti-resonance hollow core fiber (THz AR-HCF) biosensor that can be used for tumor cell detection.

Recent Progresses in Optical Biosensors for Interleukin 6 Detection.

Interleukin 6 (IL-6) is pleiotropic cytokine with pathological pro-inflammatory effects in various acute, chronic and infectious diseases. It is involved in a variety of biological processes including immune regulation, hematopoiesis, tissue repair, inflammation, oncogenesis, metabolic control, and sleep. Due to its important role as a biomarker of many types of diseases, its detection in small amounts and with high selectivity is of particular importance in medical and biological fields.

The presence of uncoated gold nanoparticle aggregates may alter the phase of phosphatidylcholine lipid as evidenced by vibrational spectroscopies.

Spherical structures built from uni- and multilamellar lipid bilayers (LUV and MLV) are nowadays considered not just as nanocarriers of various kinds of therapeutics, but also as the vehicles that, when coupled with gold (Au) nanoparticles (NPs), can also serve as a tool for imaging and discriminating healthy and diseased tissues. Since the presence of Au NPs or their aggregates may affect the properties of the drug delivery vehicle, we investigated how the shape and position of Au NP aggregates adsorbed on the surface of MLV affect the arrangement and conformation of lipid molecules. By preparing MLVs constituted from 1,2-dipalmitoyl--glycero-3-phosphocholine (DPPC) in the presence of uncoated Au NP aggregates found i) both within liposome core and on the surface of the outer lipid bilayer, or ii) adsorbed on the outer lipid bilayer surface only, we demonstrated the maintenance of lipid bilayer integrity by microscopic techniques (cryo-TEM, and AFM).

Correction: CTL-doxorubicin (DOX)-gold complex nanoparticles (DOX-AuGCs): from synthesis to enhancement of therapeutic effect on liver cancer model.

[This corrects the article DOI: 10.1039/D0NA00758G.].

Evaluation of classification ability of logistic regression model on SERS data of miRNAs.

Logistic regression (LR) is a supervised multiple linear regression model, which uses linear weighted calculation for input to obtain weight coefficients of model. The surface enhanced Raman spectroscopy (SERS) technology greatly enhances the Raman signal of analyte. LR model was used to analyze the data of seven types of pancreatic cancer-related miRNAs obtained from commercial SERS substrate.

One-step isothermal amplification strategy for microRNA specific and ultrasensitive detection based on nicking-assisted entropy-driven DNA circuit triggered exponential amplification reaction.

Sensitive and specific detection of microRNAs (miRNAs) is of critical significance for early diagnosis of cancers such as pancreatic cancer with atypical initial symptoms and high mortality. Despite exponential amplification reaction (EXPAR) is an attractive isothermal amplification method for detecting miRNAs, it faces the problems of the dependence difference and low specificity. To address such challenges, herein, a nicking-assisted entropy-driven DNA circuit triggered exponential amplification reaction (NAED-EXPAR) was firstly employed for ultrasensitive and specific detection of miRNA in "one-pot" manner at constant temperature.

New insight into the aptamer conformation and aptamer/protein interaction by surface-enhanced Raman scattering and multivariate statistical analysis.

We study the interaction between one aptamer and its analyte (the MnSOD protein) by the combination of surface-enhanced Raman scattering and multivariate statistical analysis. We observe the aptamer structure and its evolution during the interaction under different experimental conditions (in air or in buffer). Through the spectral treatment by principal component analysis of a large set of SERS data, we were able to probe the aptamer conformations and orientations relative to the surface assuming that the in-plane nucleoside modes are selectively enhanced.

Streptavidin-functionalized terahertz metamaterials for attomolar exosomal microRNA assay in pancreatic cancer based on duplex-specific nuclease-triggered rolling circle amplification.

Exosomal microRNA (miRNA) is a promising non-invasive biomarker for liquid biopsies. Herein, we fabricated a terahertz (THz) metamaterial biosensor that comprises an array of gold (Au) discs surrounded by annular grooves for exosomal miRNA assays based on duplex-specific nuclease (DSN)-triggered rolling circle amplification (RCA). In this strategy, the target miRNA is captured by a probe P0 immobilized on magnetic beads (MBs); it then repeatedly releases a primer P1 under the action of DSN, which acts as a highly specific initiator of the subsequent RCA step utilizing biotin-dUTP.

Enzyme mediated synthesis of hybrid polyedric gold nanoparticles.

Large protein complexes carry out some of the most complex activities in biology. Such structures are often assembled spontaneously through the process of self-assembly and have characteristic chemical or biological assets in the cellular mechanisms. Gold-based nanomaterials have attracted much attention in many areas of chemistry, physics and biosciences because of their size- and shape-dependent optic, electric, and catalytic properties.

A terahertz metamaterial biosensor for sensitive detection of microRNAs based on gold-nanoparticles and strand displacement amplification.

Terahertz (THz) spectroscopy has drawn great interest for the functional and conformational investigations of nucleic acids, but its intrinsic sensitivity hinders potential bio-sensing applications. Here, a novel THz biosensor was developed for detecting microRNA (miRNA) samples based on metamaterials coupled with nanoparticles and strand displacement amplification (SDA). In this method, the SDA reaction amplifies the target miRNA and generates copious yields of secondary DNA molecules (Trigger DNA), which are subsequently conjugated to metallic nanoparticles that form nanoparticle-Trigger DNA complexes.

CTL-doxorubicin (DOX)-gold complex nanoparticles (DOX-AuGCs): from synthesis to enhancement of therapeutic effect on liver cancer model.

In this work, we bring back a rapid way to conceive doxorubicin (DOX) hybrid gold nanoparticles, in which DOX and Au(iii) ions were complexed with a hydrochloride-lactose-modified chitosan, named CTL and dicarboxylic acid-terminated polyethylene-glycol (PEG), leading to hybrid polymer-sugar-metal nanoparticles (DOX-AuGSs). All formulations were assessed by spectroscopic techniques (Raman and UV-Vis) and transmission electron microscopy (TEM). To estimate the therapeutic effect of DOX-AuGSs in liver cancer, murine HepG2 cells were used to induce a hepatic carcinoma model in nude mice.

Gold Nanocylinders on Gold Film as a Multi-spectral SERS Substrate.

The surface enhanced Raman scattering (SERS) efficiency of gold nanocylinders deposited on gold thin film is studied. Exploiting the specific plasmonic properties of such substrates, we determine the influence of the nanocylinder diameter and the film thickness on the SERS signal at three different excitation wavelengths (532, 638 and 785 nm). We demonstrate that the highest signal is reached for the highest diameter of 250 nm due to coupling between the nanocylinders and for the lowest thickness (20 nm) as the excited plasmon is created at the interface between the gold and glass substrate.

Actuated plasmonic nanohole arrays for sensing and optical spectroscopy applications.

Herein, we report a new approach to rapidly actuate the plasmonic characteristics of thin gold films perforated with nanohole arrays that are coupled with arrays of gold nanoparticles. The near-field interaction between the localized and propagating surface plasmon modes supported by the structure was actively modulated by changing the distance between the nanoholes and nanoparticles and varying the refractive index symmetry of the structure. This approach was applied by using a thin responsive hydrogel cushion, which swelled and collapsed by a temperature stimulus.

Indirect surface-enhanced Raman scattering assay of insulin-like growth factor 2 receptor protein by combining the aptamer modified gold substrate and silver nanoprobes.

An indirect aptamer-based SERS assay for insulin-like growth factor 2 receptor (IGF-IIR) protein was developed. The gold substrate and silver nanoparticles (AgNPs) were employed simultaneously to achieve double enhancement for SERS signals. Firstly, the five commercial SERS substrates including Enspectr, Ocean-Au, Ocean-AG, Ocean-SP and Q-SERS substrates were evaluated using 4-mercaptobenzoic acid (4-MBA).

Towards Reliable and Quantitative Surface-Enhanced Raman Scattering (SERS): From Key Parameters to Good Analytical Practice.

Experimental results obtained in different laboratories world-wide by researchers using surface-enhanced Raman scattering (SERS) can differ significantly. We, an international team of scientists with long-standing expertise in SERS, address this issue from our perspective by presenting considerations on reliable and quantitative SERS. The central idea of this joint effort is to highlight key parameters and pitfalls that are often encountered in the literature.

Identification and investigation of the vibrational properties of crystalline and co-amorphous drugs with Raman and terahertz spectroscopy.

Co-amorphous drugs have shown significant potential in improving the stability and bioavailability compared with single neat amorphous drugs. Here, we explored the molecular interactions of cimetidine, naproxen, indomethacin and their binary co-amorphous mixtures via Raman and terahertz (THz) spectroscopy. We used quench-cooled method to prepare the neat amorphous drugs and their binary co-amorphous mixtures and tested their thermodynamic properties through differential scanning calorimetry (DSC).

Raman Tweezers for Small Microplastics and Nanoplastics Identification in Seawater.

Our understanding of the fate and distribution of micro- and nano- plastics in the marine environment is limited by the intrinsic difficulties of the techniques currently used for the detection, quantification, and chemical identification of small particles in liquid (light scattering, vibrational spectroscopies, and optical and electron microscopies). Here we introduce Raman Tweezers (RTs), namely optical tweezers combined with Raman spectroscopy, as an analytical tool for the study of micro- and nanoplastics in seawater. We show optical trapping and chemical identification of sub-20 μm plastics, down to the 50 nm range.

Label-free self-referenced sensing of living cells by terahertz metamaterial-based reflection spectroscopy.

Terahertz (THz) metamaterial-based reflection spectroscopy is proposed for label-free sensing of living cells by a self-referenced method. When sensing the living Madin-Darby canine kidney cell monolayer and phosphate buffered saline solution, self-referenced signals showed significant differences in peak intensity because of inherent discrepancy in the imaginary part of their complex refractive indices, as confirmed by 3D-FDTD simulations. The resonance peak intensity was unaffected by cell monolayer thickness variation, demonstrating feasibility for sensing various cells.

Rapid screening of colistin-resistant Escherichia coli, Acinetobacter baumannii and Pseudomonas aeruginosa by the use of Raman spectroscopy and hierarchical cluster analysis.

Colistin is recognized as the last therapeutic option for multidrug-resistant Gram-negative bacteria infection. In addition, bacterial resistance to colistin could be transmitted between different species through plasmid-mediated mcr-1 gene transfer. Therefore, rapid screening of colistin-resistant isolates will play a key role in controlling the spread of resistance and improving patient outcomes.