SERSitive substrates in publications

Insulin is a peptide hormone produced by beta cells of pancreatic islets. In type 1 diabetes mellitus, these islets are destroyed by the body’s own immune system, no insulin is produced and the blood glucose level is increased. Nowadays, efforts in combatting type 1 diabetes focus on the transplantation of islets immunoprotected in microspheres made of non-covalently crosslinked hydrogels. The functionality of the encapsulated islets is retained, while the hydrogel matrix allows permeation of the produced insulin into the bloodstream. The applicability of these microspheres has been extensively studied in vivo. However, prior to biological models, a dynamic detection method to monitor the production of insulin and its diffusion through the microspheres is still missing. Herein, we apply the Surface Enhanced Raman Scattering (SERS) technique to detect physiologically relevant concentrations of insulin using planar Ag SERS substrates, while considering their implementation for monitoring insulin diffusion through alginate matrices. Insulin was detected after drying SERS planar substrates in a concentration range of 10-3- 10-12 M. Additionally, we demonstrated the decrease in the deposition time using an alternating electric field. Moreover, the in situ monitoring of the SERS signal from insulin molecules has certain limitations when conducting experiments for SERS substrates submerged in water. As the secretion of insulin and its diffusion across the immunoprotective microspheres is a dynamic process, the development of an adequate detection method is expected to lead to a better understanding of these processes as a function of time, matrix composition, and glucose intake.
Keywords: Insulin, alginate-based hydrogel matrices, ,Surface Enhanced Raman Scattering, SERS, SERSitive
Jamelah S. Al-Otaibi, Paweł Albrycht, Y. Sheena Mary, Y. Shyma Mary & Monika Księżopolska-Gocalska
Using nanosized metal substrates, surface-enhanced Raman scattering (SERS) is a tool for improving the Raman signal of biomolecules. For detection, SERS has gained much popularity and an important role in determining chemical composition. In the present study, SERS spectra of 2-methyl-4-(4-methylpiperazin-1-yl)-10H-thieno[2,3-b][1,5]benzodiazepine (olanzapine) (MPTB) were investigated on silver and silver-gold metal substrates (SERSitive, Warsaw, Poland) at different concentrations. Also, different chemical and electronic properties are investigated using DFT calculations. The ring and other functional modes in SERS change in frequency values with variations in intensity for all concentrations. The molecule is oriented in a tilted manner with respect to Ag and Ag-Au.
Keywords: DFT, SERS, Benzodiazepine, Metal substrates, Ag, Ag-Au
Paweł Albrycht, Jamelah S. Al-Otaibi, Y. Sheena Mary, Y. Shyma Mary, Ravi Trivedi, Brahmananda Chakraborty
Surface enhanced Raman scattering (SERS) is a spectroscopic technique for trace analysis where the efficiency depends on the substrate. In the present work, concentration-dependent SERS of pioglitazone (EPMT) in silver and silver-gold substrates are reported. The presence and absence of different SERS peaks between the analyte spectra on silver and silver-gold substrates show that there is an orientation change of the analyte adsorbed depending on the surface-active metal. The density functional theory (DFT) method was used to verify the experimental findings obtained from normal Raman and SERS spectra. Theoretical modeling of EPMT and metal clusters are reported and enhancement factors are found from theoretical and experimental results. In the EPMT-Ag-Ag and EPMT-Ag-Au molecular systems, Frontier molecular orbital’s (FMO’s) results highlight charge transfers from Ag-Ag/Ag-Au clusters to the molecule. Furthermore, the SERS enhancement factor values show that EPMT is chemisorbed.
Keywords: Pioglitazone, SERS, Experimental analysis, theoretical modelling, Raman, photoscience in biology, experimental techniques, Raman spectroscopy, theoretical approaches, single molecules, synthesis methods, ultrafast photochemistry, photoscience at nanoscale, infrared spectroscopy, surface enhanced raman spectroscopy, press, sciene, big scale research,
Mocci F, Olla C, Cappai A, Corpino R, Ricci PC, Chiriu D, Salis M, Carbonaro CM.
The molecular model is one of the most appealing to explain the peculiar optical properties of Carbon nanodots (CNDs) and was proven to be successful for the bottom up synthesis, where a few molecules were recognized. Among the others, citrazinic acid is relevant for the synthesis of citric acid-based CNDs. Here we report a combined experimental and computational approach to discuss the formation of different protonated and deprotonated species of citrazinic acid and their contribution to vibrational and magnetic spectra. By computing the free energy formation in water solution, we selected the most favoured species and we retrieved their presence in the experimental surface enhanced Raman spectra. As well, the chemical shifts are discussed in terms of tautomers and rotamers of most favoured species. The expected formation of protonated and de-protonated citrazinic acid ions under extreme pH conditions was proven by evaluating specific interactions with H2SO4 and NaOH molecules. The reported results confirm that the presence of citrazinic acid and its ionic forms should be considered in the interpretation of the spectroscopic features of CNDs.
Keywords: SERS, citrazinic acid; Raman spectroscopy; NMR spectroscopy; carbon nanodots; DFT calculations
Antonio Cappai, Claudio Melis, Luigi Stagi, Pier C. Ricci, Francesca Mocci, and Carlo M. Carbonaro
The molecular emission model is the most accredited one to explain the emission properties of carbon dots (CDs) in a low-temperature bottom-up synthesis approach. In the case of citric acid and urea, the formation of a citrazinic acid (CZA) single monomer and oligomers is expected to affect the optical properties of the CDs. It is therefore mandatory to elucidate the possible role of weak bonding interactions in determining the UV absorption spectrum of some molecular aggregates of CZA. Although this carboxylic acid is largely exploited in the synthesis of luminescent CDs, a full understanding of its role in determining the final emission spectra of the produced CDs is still very far to be achieved. To this aim, by relying on purely first-principles density functional theory calculations combined with experimental optical characterization, we built and checked the stability of some molecular aggregates, which could possibly arise from the formation of oligomers of CZA, mainly dimers, trimers, and some selected tetramers. The computed vibrational fingerprint of the formation of aggregates is confirmed by surface-enhanced Raman spectroscopy. The comparison of experimental data with calculated UV absorption spectra showed a clear impact of the final morphology of the aggregates on the position of the main peaks in the UV spectra, with particular regard to the 340 nm peak associated with n-π* transition.
Keywords: SERS, Citrazinic Acid in Aqueous Solution, carbon dots
Malwina Liszewska, Bartosz Bartosewicz, Bogusław Budner, Barbara Nasiłowska, Mateusz Szala, Jan L. Weyher, Igor Dzięcielewski, Zygmunt Mierczyk, Bartłomiej J. Jankiewicz
Raman spectroscopy has become an essential analytical technique for field detection and identification of illicit or dangerous materials such as explosives, but its main drawback is low signal intensity. This problem can be circumvented by using surface enhanced Raman spectroscopy (SERS), in which scattering signals increase significantly for analytes adsorbed onto or near nano structured surfaces of the plasmonic materials. However,despite numerous studies, SERS has still not been widely used in real-world applications. The main goal of the studies describe herein was to investigate the possibility of detection of trace amounts of selected explosive materials on various commercial and non-commercial SERS substrates using portable Raman instruments. Our studies have shown that while portable systems suitable for SERS measurement of trace amounts of explosives are readily available, the problem remains in the selection of reliable and reproducible SERS substrates. Among five investigated SERS substrates only two, Klarite 312 and GaN-pillars allowed for trace analysis of all studied explosive materials. In both cases, detected concentrations of explosives ranged from single to hundreds of μg/cm2 depending on the explosive material and the Raman spectrometer used. Based on our findings, it could be concluded that the best SERS substrates for trace analysis of explosives are substrates with hot spots densely and evenly distributed over a whole active area of SERS substrate
Keywords: Explosives, SERS, SERS substrates, Portable Raman spectroscopy, Trace detection
Byram Chandu, Moram Sree Satya Bharati, Paweł Albrycht, Soma Venugopal Rao
Over the last decade several research groups have accomplished the fabrication of 2D periodic and 3D nanocage like structures on different materials using diverse lithographic approaches. Herein, we present the detailed studies on the fabrication of femtosecond (fs) laser‐induced periodic/ripple‐like surface structures on nickel (Ni) substrate in distilled water whereas 3D-like (nanocages) features on Ni substrates in acetone by tailoring the laser processing parameters (pulse energy). The morphological studies of simultaneously obtained Ni nanoparticles (NPs)/nanostructures (NSs) in distilled water/acetone were meticulously studied using transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM). The fabricated Ni periodic/3D-like structures were gold (Au) plated using thermal evaporation technique and subsequently utilized as surface enhanced Raman scattering (SERS) active sensors for detecting the traces of various analyte molecules such as malachite green (MG) and Nile blue (NB). The grooved Ni-Au substrates allowed us to detect extremely low concentrations of MG (500 pM) and NB (5 nM) and, significantly, utilizing a simple, portable Raman spectrometer. Moreover, the substrates have demonstrated superior reproducibility as well as multi-utility nature with a relative standard deviation (RSD) of <17%. Additionally, Au- coated Ni grooved SERS substrates have demonstrated superior sensitivity and reproducibility in comparison to commercially available Ag-based SERS sensors (SERSitive, Poland). The proposed method of fabricating ripple and nanocages of Ni SERS platforms are highly viable to overcome the cost and one-time usage of substrates for on-site detection of several analyte molecules using a portable/hand-held Raman spectrometer.
Keywords: Laser Induced Periodic Surface Structures (LIPSS), Malachite green, Nanocages, Nickel Nanostructure (NS), Nile blue, SERS, Substrates, Surface scattering, Laser ablation, Raman, Relative standard deviations
Łukasz Richter, Paweł Albrycht, Monika Księżopolska-Gocalska, Ewa Poboży, Robert Bachlińskic, Volodymyr Sashuk, Jan Paczesny, Robert Hołyst
The majority of analytical chemistry methods requires presence of target molecules directly at a sensing surface. Diffusion of analyte from the bulk towards the sensing layer is random and might be extremely lengthy, especially in case of low concentration of molecules to be detected. Thus, even the most sensitive transducer and the most selective sensing layer are limited by the efficiency of deposition of molecules on sensing surfaces. However, rapid development of new sensing technologies is rarely accompanied by new protocols for analyte deposition. To bridge this gap, we propose a method for fast and efficient deposition of variety of molecules (e.g. proteins, dyes, drugs, biomarkers, amino acids) based on application of the alternating electric field. We show the dependence between frequency of the applied electric field, the intensity of the surface enhanced Raman spectroscopy (SERS) signal and the mobility of the studied analyte. Such correlation allows for a priori selection of parameters for any desired compound without additional optimization. Thanks to the application of the electric field, we improve SERS technique by decrease of time of deposition from 20 h to 5 min, and, at the same time, reduction of the required sample volume from 2 ml to 50 μl. Our method might be paired with number of analytical methods, as it allows for deposition of molecules on any conductive surface, or a conductive surface covered with dielectric layer.
Keywords: Deposition, Electric field, Surface-enhanced Raman spectroscopy, SERS, Analyte, Detection
Dávid J. Palásti, Paweł Albrycht, Patrick Janovszky, Karolina Paszkowska, Zsolt Geretovszky and Gábor Galbács
An assessment of the feasibility of using modified surface enhanced Raman scattering substrates (Ag nanoparticles on indium‑tin-oxide glass) for quantitative nanoparticle-enhanced laser induced breakdown spectroscopy (NELIBS) was carried out. Substrates were prepared with different surface coverage from various nanoparticle sizes, and their laser ablation behaviour was tested in detail. It was found that use of those combinations are most beneficial in terms of the signal enhancement factor, which provide the shortest interparticle distances. With the application of 266 nm laser wavelength, long (ms-range) gate width, and optimized laser pulse energy, the best NELIBS signal enhancement was found to be about a factor of three. By using liquid sample deposition by spraying, which was found to provide an even distribution of liquid samples on the substrate surface, successful calibration for Mn, Zn and Cr was performed. The NELIBS signal repeatability from five repeated measurements was found to be comparable to that of LIBS (5–10% RSD). These observations indicate that the NELIBS signal enhancement approach can be used in quantitative analytical applications for liquid samples, if i) the substrate fabrication procedure has good repeatability, ii) surface coverage and nanoparticle size is tightly controlled, iii) a homogenous liquid sample deposition is achieved.
Keywords: Laser induced breakdown spectroscopy (LIBS); Nanoparticle enhanced LIBS (NELIBS); Silver nanoparticles; Indium‑tin-oxide (ITO) glass; SERS
Mss Bharathi, Abdul Kalam, Chandu Byram, Syed Hamad and Venugopal Rao Soma
The development of recyclable surface enhanced Raman scattering (SERS) based sensors has been in huge demand for trace level explosives detection. A simple, hybrid Silicon (Si) nanotextured target-based SERS platform is fabricated through patterning micro square arrays (MSA) on Si using femtosecond (fs) laser ablation technique at different fluences. Using the hybrid target Si MSA substrate loaded/decorated with Ag-Au alloy NPs (obtained using femtosecond ablation in liquids) we demonstrate the trace level detection of organic nitro-explosives [picric acid (PA), 2,4-dinitrotoluene (DNT), and 1, 3, 5-trinitroperhydro-1, 3, 5-triazine (RDX)] and their mixtures. The microstructures/nanostructures of MSA fabricated at an input fluence of 9.55 J/cm2, and decorated with Ag-Au alloy NPs, exhibited exceptional SERS enhancement factors (EFs) up to ∼1010 for MB, ∼106 for PA, and ∼104 for RDX with the detection limits obtained being ∼5 pM, ∼36 nM, and ∼400 nM for MB, PA and RDX respectively. Furthermore, we demonstrate these SERS substrates possess good reproducibility (RSD values < 15%) and a superior performance compared to a commercial Ag substrate (SERSitive, Poland). Three binary mixtures, i.e. MB-PA, MB-DNT, PA-DNT at different concentrations, were also investigated using the same SERS substrate to test the efficacy. Further, the SERS spectra of dyes, explosives, and complex mixtures were utilized for discrimination/classification using principal component analysis.
Keywords: Surface-enhanced Raman scattering, Femtosecond laser ablation, Ag–Au alloy NPs, Methylene blue, Explosives detection

Patent applications with SERSitive substrates:

EU Patent no. EP 18165322


"A method of depositing metal nanoparticles on a surface in an electrochemical process, the surface obtained by this method and its application"

Patent no. P.408785


“Method for depositing metal nanoparticles on a surface in the electrochemical process, surface obtained by this method and its application“

Patent no. P.412548


“Method for applying of analyte from a solution on the substrate for the surface-strengthened spectroscopy in electric field“

Patent no. P.416927


“Method for detection bacteria Salmonella spp, Cronobacter spp oraz Listeria monocytogenes in the food“

Patent no. P.421072


“Method for depositing metal nanoparticles on a surface in the electrochemical process, surface obtained by this method and its application“