Ewa Borowiec

Bio: Ewa Borowiec is an academic researcher. The author has contributed to research in topics: Raman spectroscopy. The author has an hindex of 1, co-authored 1 publications receiving 50 citations.

Food additives characterization by infrared, Raman, and surface‐enhanced Raman spectroscopies

Abstract: Fourier-transform infrared (FT-IR), Raman (RS), and surface-enhanced Raman scattering (SERS) spectra of β-hydroxy-β-methylobutanoic acid (HMB), L-carnitine, and N-methylglycocyamine (creatine) have been measured. The SERS spectra have been taken from species adsorbed on a colloidal silver surface. The respective FT-IR and RS band assignments (solid-state samples) based on the literature data have been proposed. The strongest absorptions in the FT-IR spectrum of creatine are observed at 1398, 1615, and 1699 cm−1, which are due to νs(COOH) + ν(CN) + δ(CN), ρs(NH2), and ν(CO) modes, respectively, whereas those of L-carnitine (at 1396/1586 cm−1 and 1480 cm−1) and HMB (at 1405/1555/1585 cm−1 and 1437–1473 cm−1) are associated with carboxyl and methyl/methylene group vibrations, respectively. On the other hand, the strongest bands in the RS spectrum of HMB observed at 748/1442/1462 cm−1 and 1408 cm−1 are due to methyl/methylene deformations and carboxyl group vibrations, respectively. The strongest Raman band of creatine at 831 cm−1 (ρw(RNH2)) is accompanied by two weaker bands at 1054 and 1397 cm−1 due to ν(CN) + ν(RNH2) and νs(COOH) + ν(CN) + δ(CN) modes, respectively. In the case of L-carnitine, its RS spectrum is dominated by bands at 772 and 1461 cm−1 assigned to ρr(CH2) and δ(CH3), respectively. The analysis of the SERS spectra shows that HMB interacts with the silver surface mainly through the COO−, hydroxyl, and CH2 groups, whereas L-carnitine binds to the surface via COO− and N+(CH3)3 which is rarely enhanced at pH = 8.3. On the other hand, it seems that creatine binds weakly to the silver surface mainly by NH2, and CO from the COO− group. Copyright © 2006 John Wiley & Sons, Ltd.

Surface-Enhanced Raman Spectroscopy for the Chemical Analysis of Food

Abstract: Surface-enhanced Raman spectroscopy (SERS) is an emerging and promising technique for the chemical analysis of food. The use of metallic nanosubstrates improves the sensitivity and capacity of conventional Raman spectroscopy greatly. This paper comprehensively reviews the development and applications of SERS in the chemical analysis of food, mainly focusing on food additives and chemical contaminants. The progress of SERS development and their applications in chemical analysis of food, from detection and characterization of target analytes in simple solvents to complex food matrices, is summarized. The advantages and limitations of different SERS substrates and methodologies are discussed. As most of the current SERS research on chemical analysis of food is still in an early stage, there are still several hurdles for further advancing SERS techniques into real-world applications for complex food products. This review includes our perspectives on the future trends of the SERS technique in the field of food analysis.

Recent Advances in linear and nonlinear Raman spectroscopy I

Abstract: Raman spectroscopy has advanced considerably in the last several years due to rapid developments in instrumentation and the availability of theoretical methods for accurate calculation of Raman spectra, thus enormously facilitating the interpretation of Raman data. This review is restricted to cover papers mainly published in the Journal of Raman Spectroscopy, which serve to give a fast overview of recent advances in this research field as well as to provide readers of this journal a quick introduction to the various subfields of Raman spectroscopy. It also reflects the current research interests of the Raman community. Similar reviews of highly active areas of Raman spectroscopy will appear in future issues of this journal. Copyright © 2007 John Wiley & Sons, Ltd.

Determination of chloramphenicol and crystal violet with surface enhanced Raman spectroscopy

Abstract: Residual chloramphenicol, crystal violet and other illegal drugs in fish pose potential health risks and adverse impact to the aquatic environment, and are important concerns of consumers and regulatory agencies. Surface enhanced Raman spectroscopy (SERS) with two different types of SERS-active substrates were used to collect the spectra of chloramphenicol and crystal violet over a concentration range of 10 ng/mL to10 μg/mL. Partial least squares regression and multiple linear regression models were developed for quantitative prediction of these drugs from their spectral data (n = 32). The limit of detection for chloramphenicol and crystal violet was 50 and 20 ng/mL, respectively, and R2 values of chemometric models were from 0.82 to 0.87, indicating potential of applying SERS for determination of trace amounts of prohibited substances in food.

Enzymatic Micromotors as a Mobile Photosensitizer Platform for Highly Efficient On-Chip Targeted Antibacteria Photodynamic Therapy

Abstract: Photodynamic therapy (PDT) functions when the light-excited photosensitizers transfer energy to oxygen molecules (O2) to produce cytotoxic singlet oxygen (O2) that can effectively kill cells or bacteria. However, the PDT efficacy is often reduced by the limited availability of O2 surrounding the photosensitizer and extremely short diffusion range of the photoactivated O2. Herein, an enzymatic micromotor based on hollow mesoporous SiO2 (mSiO2) microspheres is constructed as a mobile and highly efficient photosensitizer platform. Carboxylated magnetic nanoparticles are connected with both hollow spheres and 5,10,15,20-tetrakis(4-aminophenyl)porphyrin molecules through covalent linkage between amino and carboxylic groups within a one-step reaction. Due to the intrinsic asymmetry of the mSiO2 spheres, the micromotors can be propelled by ionic diffusiophoresis induced by the enzymatic decomposition of urea. Via numerical simulation, the self-propulsion mechanism is clarified and the movement direction is identified. By virtue of active self-propulsion, the current system can overcome the long-standing shortcomings of PDT and significantly enhance the PDT efficacy by improving the accessibility of the photosensitizer to O2 and enlarging the diffusing range of O2. Therefore, by proposing a new solution to the bottleneck problems of PDT, this work provides insightful perspectives to the biomedical application of multifunctional micro/nanomotors.