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The use of surface‐enhanced Raman scattering (SERS) as a technique for detecting small amounts of (bio)chemical analytes has become increasingly popular in various fields. While gold and silver nanostructures have been extensively studied as SERS substrates, the availability of other types of substrates is currently expanding the applications of this spectroscopic method. Recently, researchers have begun exploring two‐dimensional (2D) materials (e. g., graphene‐like nanostructures) as substrates for SERS analysis. These materials offer unique optical properties, a well‐defined structure, and the ability to modify their surface chemistry. As a contribution to advance this field, this concept article highlights the significance of understanding the chemical mechanism that underlies the experimental Raman spectra of chemisorbed molecules onto 2D materials' surfaces. Therefore, the article discusses recent advancements in fabricating substrates using 2D layered materials and the synergic effects of using their metallic composites for SERS applications. Additionally, it provides a new perspective on using Raman imaging in developing 2D materials as analytical platforms for Raman spectroscopy, an exciting emerging research area with significant potential. [ABSTRACT FROM AUTHOR]

Fast detection of contaminants of emerging concern (CECs) in water resources is of great environmental interest. Ideally, sustainable materials should be used in water quality monitoring technologies implemented for such purposes. In this regard, the application of bio-based materials aimed at the fabrication of analytical platforms has become of great importance. This research merges both endeavors by exploring the application of chitosan-coated paper, decorated with silver nanoparticles (AgNPs), on surface-enhanced Raman scattering (SERS) spectroscopy studies of two distinct types of CECs dissolved in aqueous samples: an antibiotic (ciprofloxacin) and a pesticide (thiram). Our results indicate the superior SERS performance of biocoated substrates compared to their non-coated paper counterparts. The detection limits achieved for thiram and ciprofloxacin using the biocoated substrates were 0.024 ppm and 7.7 ppm, respectively. The efficient detection of both analytes is interpreted in terms of the role of the biopolymer in promoting AgNPs assemblies that result in local regions of enhanced SERS activity. Taking advantage of these observations, we use confocal Raman microscopy to obtain Raman images of the substrates using ciprofloxacin and thiram as molecular probes. We also demonstrate that these biobased substrates can be promising for on-site analysis when used in conjunction with portable Raman instruments. [ABSTRACT FROM AUTHOR]

The functionalization of deoxyribonucleic acid (DNA) with nanomaterials is a promising strategy to optimize the loading and efficiency of drugs in targeted clinical therapies. Herein we report a novel approach to construct arrays comprising blue- (B) or aqua green- (AG) emitting ethylenediamine-modified graphene quantum dots (GQDs) and DNA oligonucleotides that are able to fold into different structures, namely G-quadruplexes (G4s). The obtained results indicate that GQDs partially modulate the conformation of oligonucleotides, resulting in GQDs-DNA bioconjugates with higher affinity to carry 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP), in comparison to non-modified DNA sequences. TMPyP shows a higher affinity, expressed by a lower dissociation constant (KD), to GQDs-B-G4-1 (0.229 μM) and to GQDs-AG-G4-1 (KD of 0.326 μM) in comparison with non-modified G4-1 (KD of 0.440 μM). The carrier systems with the highest affinity to TMPyP correspond to GQDs-AG with telomeric unimolecular G4 sequence (GQDs-AG-G4-2, KD of 0.111 μM) and GQDs-AG with a non-G4 sequence (GQDs-AG-non-G4, KD of 0.110 μM), followed by their analogues with GQDs-B. While uncovering terra incognita, it is anticipated that GQDs-DNA arrays may be potential photoluminescent nanovehicles to carry other cationic anticancer drugs and allow more targeted therapies. [ABSTRACT FROM AUTHOR]

The manufacture of sustainable functional fibers with low environmental footprint and superior properties is a pressing research issue under the auspices of more sustainable industrial textile processes. In the present study, regenerated cellulose fibers (CellReg) with flame retardancy properties are manufactured by functionalizing regenerated wood pulp fibers (obtained through the dissolution of paper‐grade pulp in an ionic liquid followed by regeneration in water) with a natural derived phosphorus compound, namely phytic acid ammonium (PAA). The pale‐yellow modified fibers present a phosphorus content up to 1.80% and a uniform and smooth surface morphology. Furthermore, the functional cellulose fibers exhibit moderate antioxidant activity (ca. 18.4% of maximum radical scavenging), water contact angles below 92°, as well as good thermal‐oxidative stability up to 200°C. The flame‐retardant performance of the CellReg/PAA fibers was investigated by the vertical burning test, and as anticipated, the results show a higher flame retardancy with the increasing content of phosphorus, meaning that the fibers ceased to burn before flaming or glowing, even after several flame applications. The accomplished properties validate the potential of these functional fibers of regenerated wood pulp cellulose and PAA for application as textile fibers with flame retardancy properties. [ABSTRACT FROM AUTHOR]

The activation of T helper (Th) lymphocytes is necessary for the adaptive immune response as they contribute to the stimulation of B cells (for the secretion of antibodies) and macrophages (for phagocytosis and destruction of pathogens) and are necessary for cytotoxic T-cell activation to kill infected target cells. For these issues, Th lymphocytes must be converted into Th effector cells after their stimulation through their surface receptors TCR/CD3 (by binding to peptide-major histocompatibility complex localized on antigen-presenting cells) and the CD4 co-receptor. After stimulation, Th cells proliferate and differentiate into subpopulations, like Th1, Th2 or Th17, with different functions during the adaptative immune response. Due to the central role of the activation of Th lymphocytes for an accurate adaptative immune response and considering recent preclinical advances in the use of nanomaterials to enhance T-cell therapy, we evaluated in vitro the effects of graphene oxide (GO) and two types of reduced GO (rGO15 and rGO30) nanostructures on the Th2 lymphocyte cell line SR.D10. This cell line offers the possibility of studying their activation threshold by employing soluble antibodies against TCR/CD3 and against CD4, as well as the simultaneous activation of these two receptors. In the present study, the effects of GO, rGO15 and rGO30 on the activation/proliferation rate of these Th2 lymphocytes have been analyzed by studying cell viability, cell cycle phases, intracellular content of reactive oxygen species (ROS) and cytokine secretion. High lymphocyte viability values were obtained after treatment with these nanostructures, as well as increased proliferation in the presence of rGOs. Moreover, rGO15 treatment decreased the intracellular ROS content of Th2 cells in all stimulated conditions. The analysis of these parameters showed that the presence of these GO and rGO nanostructures did not alter the response of Th2 lymphocytes. [ABSTRACT FROM AUTHOR]