Gabriela Fabriciova

Bio: Gabriela Fabriciova is an academic researcher from Spanish National Research Council. The author has contributed to research in topics: Raman spectroscopy & Chemistry. The author has an hindex of 8, co-authored 10 publications receiving 311 citations.

Sensitive Surface-Enhanced Raman Spectroscopy (SERS) Detection of Organochlorine Pesticides by Alkyl Dithiol-Functionalized Metal Nanoparticles-Induced Plasmonic Hot Spots

Abstract: In this work, we report the detection of the organochlorine pesticides aldrin, dieldrin, lindane, and α-endosulfan by using surface-enhanced Raman spectroscopy (SERS) and optimization of the SERS-sensing substrate. In order to overcome the inherent problem of the low affinity of the above pesticides, we have developed a strategy consisting of functionalization of the metal surface with alkyl dithiols in order to achieve two different goals: (i) to induce the nanoparticle linkage and create interparticle junctions where sensitive hot spots needed for SERS enhancement are present, and (ii) to create a specific environment in the nanogaps between silver and gold nanoparticles, making them suitable for the assembly and SERS detection of the analyzed pesticides. Afterward, an optimization of the sensing substrate was performed by varying the experimental conditions: type of metal nanoparticles, molecular linker (aromatic versus aliphatic dithiols and the length of the intermediate chain), surface coverage, las...

Surface-enhanced Raman spectroscopy study of the interaction of the antitumoral drug emodin with human serum albumin.

Abstract: Surface-enhanced Raman spectroscopy was employed in this work to study the interaction between the antitumoral drug emodin and human serum albumin (HSA), as well as the influence of fatty acids in this interaction. We demonstrated that the drug/protein interaction can take place through two different binding sites which are probably localized in the IIA and IIIA hydrophobic pockets of HSA and which correspond to Sudlow's I and II binding sites, respectively. The primary interaction site of this drug seems to be site II in the defatted albumin. Fatty acids seem to displace the drug from site II to site I in nondefatted HSA, due to the high affinity of fatty acids for site II. The drug interacts with the protein through its dianionic form in defatted HSA (when placed in the site II) and through its neutral form in the site I of nondefatted albumins.

Interaction of Hypericin with Serum Albumins: Surface-enhanced Raman Spectroscopy, Resonance Raman Spectroscopy and Molecular Modeling Study¶

Abstract: Surface-enhanced Raman spectroscopy, resonance Raman spectroscopy and molecular modeling were employed to study the interaction of hypericin (Hyp) with human (HSA), rat (RSA) and bovine (BSA) serum albumins. The identification of the binding site of Hyp in serum albumins as well as the structural model for Hyp/HSA complex are presented. The interactions mainly reflect: (1) a change of the strength of H bonding at the N1-H site of Trp; (2) a change of the Trp side-chain conformation; (3) a change of the hydrophobicity of the Trp environment; and (4) a formation of an H-bond between the carbonyl group of Hyp and a proton donor in HSA and RSA which leads to a protonated-like carbonyl in Hyp. Our results indicate that Hyp is rigidly bound in IIA subdomain of HSA close to Trp214 (distance 5.12 A between the centers of masses). In the model presented the carbonyl group of Hyp is hydrogen bonded to Asn458. Two other candidates for hydrogen bonds have been identified between the bay-region hydroxyl group of Hyp and the carbonyl group of the Trp214 peptidic link and between the peri-region hydroxyl group of Hyp and the Asn458 carbonyl group. It is shown that the structures of the Hyp/HSA and Hyp/RSA complexes are similar to, and in some aspects different from, those found for the Hyp/BSA complex. The role of aminoacid sequence in the IIA subdomains of HSA, RSA and BSA is discussed to explain the observed differences.

Joint application of micro-Raman and surface-enhanced Raman spectroscopy to the interaction study of the antitumoral anthraquinone drugs danthron and quinizarin with albumins

Abstract: We report on the joint application of surface-enhanced Raman scattering (SERS) and micro-Raman techniques to the study of danthron (DT) and quinizarin (QZ) and their complexes with human and bovine albumins. We propose a novel method based on the combination of SERS and micro-Raman spectroscopy by using immobilized Ag nanoparticles, which we have named micro-SERS, to improve the sensitivity of the SERS technique and that could be applied in recognition processes of drugs with large biomolecules. The micro-SERS technique demonstrated clear advantages over direct measurements in air: reproducibility, rapidity and high sensitivity due to a large coverage of the metal surface and good organization of the adsorbate on the surface. Furthermore, the chemical damage of the analyte induced by laser irradiation is substantially reduced. By means of this method, we were able to deduce important information concerning the binding properties of DT and QZ when interacting with human and bovine albumins. For instance, the interaction mechanism can be drastically modified when fatty acids are present in albumins, there are large differences between human and bovine albumins in the binding of the studied drugs related to changes in the amino-acid sequence of the binding pockets of these proteins and the interaction mechanism of the analysed drugs can be different depending on their structure. Copyright  2004 John Wiley & Sons, Ltd.

Review of SERS Substrates for Chemical Sensing.

Abstract: The SERS effect was initially discovered in the 1970s. Early research focused on understanding the phenomenon and increasing enhancement to achieve single molecule detection. From the mid-1980s to early 1990s, research started to move away from obtaining a fundamental understanding of the phenomenon to the exploration of analytical applications. At the same time, significant developments occurred in the field of photonics that led to the advent of inexpensive, robust, compact, field-deployable Raman systems. The 1990s also saw rapid development in nanoscience. This convergence of technologies (photonics and nanoscience) has led to accelerated development of SERS substrates to detect a wide range of chemical and biological analytes. It would be a monumental task to discuss all the different kinds of SERS substrates that have been explored. Likewise, it would be impossible to discuss the use of SERS for both chemical and biological detection. Instead, a review of the most common metallic (Ag, Cu, and Au) SERS substrates for chemical detection only is discussed, as well as SERS substrates that are commercially available. Other issues with SERS for chemical detection have been selectivity, reversibility, and reusability of the substrates. How these issues have been addressed is also discussed in this review.

Review of surface enhanced Raman spectroscopic (SERS) detection of synthetic chemical pesticides

Abstract: Pesticides are essential in modern agricultural practices. Detection of pesticides is an essential step in regulating and monitoring the levels of pesticides in the environment. Even though GC/LC-MS is often the gold standard method for pesticide detection, recent technological advancements has promoted the creation of alternative techniques, such as Surface Enhanced Raman Spectroscopy (SERS), that provide added advantages such as ultrasensitive detection, faster turnover, simpler protocols, in situ sampling, on-site capability and reduced cost. In this review, a comprehensive report of recent advances in SERS detection of synthetic chemical pesticides is given. The development and applications of the SERS technique for pesticide detection in both simple and complex matrices are discussed. The main advantages of using SERS for pesticide detection are highlighted, together with its limitations. Lastly, promising future trends and applications of SERS for pesticides detection are also discussed.

Biological applications of localised surface plasmonic phenomenae

Abstract: Researchers and industrialists have taken advantage of the unusual optical, magnetic, electronic, catalytic, and mechanical properties of nanomaterials. Nanoparticles and nanoscale materials have proven to be useful for biological uses. Nanoscale materials hold a particular interest to those in the biological sciences because they are on the same size scale as biological macromolecules, proteins and nucleic acids. The interactions between biomolecules and nanomaterials have formed the basis for a number of applications including detection, biosensing, cellular and in situ hybridisation labelling, cell tagging and sorting, point-of-care diagnostics, kinetic and binding studies, imaging enhancers, and even as potential therapeutic agents. Noble metal nanoparticles are especially interesting because of their unusual optical properties which arise from their ability to support surface plasmons. In this review the authors focus on biological applications and technologies that utilise two types of related plasmonic phenomonae: localised surface plasmon resonance (LSPR) spectroscopy and surface-enhanced Raman spectroscopy (SERS). The background necessary to understand the application of LSPR and SERS to biological problems is presented and illustrative examples of resonant Rayleigh scattering, refractive index sensing, and SERS-based detection and labelling are discussed.

Review of optical sensors for pesticides

Abstract: Sensors for pesticides with high sensitivity have been urgently required to control food safety, protect ecosystem and prevent disease. In this review, we provide an overview of recent advances and new trends in optical sensors for the detection of pesticide based on fluorescence, colorimetric and surface enhanced Raman scattering, surface plasmon resonance and chemiluminescent strategies. These methods will be classified by the types of recognition elements, including enzyme, antibody, molecularly-imprinted polymers, aptamer and host-guest reaction. This review explores the basic features of established strategies through assessment of their performance. In addition, we provide brief summary of the entire review, the drawbacks of present sensor and future prospects, as well as the ongoing efforts to pesticide optical sensors.