Cationic amino-acid functionalized polymethacrylamide vectors for siRNA transfection based on modification of poly(2-isopropenyl-2-oxazoline).

Poly(2-isopropenyl-2-oxazoline) (PiPOx) is a functional polymer showing great potential for the development of smart biomaterials. The straightforward synthesis and post-polymerization functionalization of PiPOx offers many opportunities for tailoring the properties of the polymer towards biomaterials. In this study we report for the first time PiPOx-based cationic charged polymethacrylamides with amino acid side chains that can complex siRNA and promote transfection in vitro. Therefore, PiPOx was fully modified via ring opening addition reactions with the carboxylic acid groups of a series of N-Boc-L-amino acids and their reaction kinetics were investigated. Based on the determined kinetic constants, another series of PiPOx-based copolymers with balanced hydrophilic/hydrophobic content of N-Boc-L-amino acids were obtained via one-pot modification reaction with two different N-Boc-L-amino acids. The N-Boc protected homopolymers and related copolymers were deprotected to obtain (co)polymers with the targeted side chain cationic charged units. The (co)polymers' structures were fully investigated via FT-IR and 1H NMR spectroscopy, size exclusion chromatography (SEC), and TGA-DSC-MS analysis. The polarimetry measurements revealed that the homopolymers retain their chiroptical properties after post-modification, and a sign inversion is noticed from (L) N-Boc-protected analogues to (D) for the TFA cationic charged homopolymers. Generally, cationically charged homopolymers with hydrophilic amino acids on the side chain showed efficient complexation of siRNA, but poor transfection while cationic copolymers having both tryptophan and valine or proline side chains revealed moderate siRNA binding, high transfection efficiency (> 90% of the cells) and potent gene silencing with IC50 values down to 5.5 nM. Particularly, these cationic copolymers showed higher gene silencing potency as compared to the commercial JetPRIME® reference, without reducing cell viability in the concentration range used for transfection, making this a very interesting system for in vitro siRNA transfection.

The alpha-adrenergic antagonist prazosin promotes cytosolic siRNA delivery from lysosomal compartments.

The widespread use of small interfering RNA (siRNA) is limited by the multiple extra- and intracellular barriers upon in vivo administration. Hence, suitable delivery systems, based on siRNA encapsulation in nanoparticles or its conjugation to targeting ligands, have been developed. Nevertheless, at the intracellular level, these state-of-the-art delivery systems still suffer from a low endosomal escape efficiency. Consequently, the bulk of the endocytosed siRNA drug rapidly accumulates in the lysosomal compartment. We recently reported that a wide variety of cationic amphiphilic drugs (CADs) can promote small nucleic acid delivery from the endolysosomal compartment into the cytosol via transient induction of lysosomal membrane permeabilization. Here, we describe the identification of alternate siRNA delivery enhancers from the NIH Clinical Compound Collection that do not have the typical physicochemical properties of CADs. Additionally, we demonstrate improved endolysosomal escape of siRNA via a cholesterol conjugate and polymeric carriers with the α1-adrenergic antagonist prazosin, which was identified as the best performing delivery enhancer from the compound screen. A more detailed assessment of the mode-of-action of prazosin suggests that a different cellular phenotype compared to typical CAD adjuvants drives cytosolic siRNA delivery. As it has been described in the literature that prazosin also induces cancer cell apoptosis and promotes antigen cross-presentation in dendritic cells, the proof-of-concept data in this work provides opportunities for the repurposing of prazosin in an anti-cancer combination strategy with siRNA.

Repositioning the antihistamine ebastine as an intracellular siRNA delivery enhancer.

Small interfering RNAs (siRNAs) are promising therapeutics for the treatment of human diseases via the induction of sequence-specific gene silencing. To be functional, siRNAs require cytosolic delivery into target cells. However, state-of-the-art delivery systems mediate cellular entry through endocytosis and suffer from ineffective endosomal escape, routing a substantial fraction of the siRNA towards the lysosomal compartment. Cationic amphiphilic drugs (CADs) have been described to improve cytosolic siRNA delivery by the transient induction of lysosomal membrane permeabilization. In this work, we evaluated ebastine, an antihistamine CAD, for its ability to enhance cytosolic release of siRNA in a non-small cell lung cancer model. In particular, we demonstrated that ebastine can improve the siRNA-mediated gene silencing efficiency of a polymeric nanogel by 40-fold, outperforming other CAD compounds. Additionally, ebastine substantially enhanced gene knockdown of a cholesterol-conjugated siRNA, in two-dimensional (2D) cell culture as well as in three-dimensional (3D) tumor spheroids. Finally, ebastine could strongly promote siRNA delivery of lipid nanoparticles (LNPs) composed of a pH-dependent switchable ionizable lipid and with stable PEGylation, in contrast to state-of-the-art LNP formulations. Altogether, we identified ebastine as a potent and versatile siRNA delivery enhancer in cancer cells, which offers opportunities for drug combination therapy in oncology.

Toward microfluidic SERS and EC-SERS applications via tunable gold films over nanospheres.

Many promising applications of surface-enhanced Raman scattering (SERS), such as microfluidic SERS and electrochemical (EC)-SERS, require immersion of plasmonic nanostructured films in aqueous media. Correlational investigations of the optical response and SERS efficiency of solid SERS substrates immersed in water are absent in the literature. This work presents an approach for tuning the efficiency of gold films over nanospheres (AuFoN) as SERS substrates for applications in aqueous environment. AuFoN are fabricated by convective self-assembly of colloidal polystyrene nanospheres of various diameters (300-800 nm), followed by magnetron sputtering of gold films. The optical reflectance of the AuFoN and Finite-Difference Time-Domain simulations in both water and air reveal the dependence of the surface plasmon band on nanospheres' diameter and environment. SERS enhancement of a common Raman reporter on AuFoN immersed in water is analyzed under 785 nm laser excitation, but also using the 633 nm line for the films in air. The provided correlations between the SERS efficiency and optical response in both air and water indicate the best structural parameters for high SERS efficiency and highlight a route for predicting and optimizing the SERS response of AuFoN in water based on the behavior in air, which is more practical. Finally, the AuFoN are successfully tested as electrodes for EC-SERS detection of the thiabendazole pesticide and as SERS substrates integrated in a flow-through microchannel format. The obtained results represent an important step toward the development of microfluidic EC-SERS devices for sensing applications.

Gold vs. Silver Colloidal Nanoparticle Films for Optimized SERS Detection of Propranolol and Electrochemical-SERS Analyses.

The increasing pollution of surface and groundwater bodies by pharmaceuticals is a general environmental problem requiring routine monitoring. Conventional analytical techniques used to quantify traces of pharmaceuticals are relatively expensive and generally demand long analysis times, associated with difficulties in performing field analyses. Propranolol, a widely used ß-blocker, is representative of an emerging class of pharmaceutical pollutants with a noticeable presence in the aquatic environment. In this context, we focused on developing an innovative, highly accessible analytical platform based on self-assembled metal colloidal nanoparticle films for the fast and sensitive detection of propranolol based on Surface Enhanced Raman Spectroscopy (SERS). The ideal nature of the metal used as the active SERS substrate was investigated by comparing silver and gold self-assembled colloidal nanoparticle films, and the improved enhancement observed on the gold substrate was discussed and supported by Density Functional Theory calculations, optical spectra analyses, and Finite-Difference Time-Domain simulations. Next, direct detection of propranolol at low concentrations was demonstrated, reaching the ppb regime. Finally, we showed that the self-assembled gold nanoparticle films could be successfully used as working electrodes in electrochemical-SERS analyses, opening the possibility of implementing them in a wide array of analytical applications and fundamental studies. This study reports for the first time a direct comparison between gold and silver nanoparticle films and, thus, contributes to a more rational design of nanoparticle-based SERS substrates for sensing applications.

Influence of the Size and Charge of Carbon Quantum Dots on Their Corneal Penetration and Permeation Enhancing Properties.

Reaching the corneal endothelium through the topical administration of therapeutic drugs remains a challenge in ophthalmology. Besides, endothelial cells are not able to regenerate, and diseases at this site can lead to corneal blindness. Targeting the corneal endothelium implies efficient penetration through the three corneal layers, which still remains difficult for small molecules. Carbon quantum dots (CQDs) have demonstrated great potential for ocular nanomedicine. This study focuses on the corneal penetration abilities of differently charged CQDs and their use as permeation enhancers for drugs. Excised whole bovine eyes were used as an ex vivo model to investigate corneal penetration of CQDs derived from glucosamine using ß-alanine, ethylenediamine, or spermidine as a passivation agent. It was found that negatively charged CQDs have limited corneal penetration ability, while positively charged CQDs derived from glucosamine hydrochloride and spermidine (CQD-S) penetrate the entire corneal epithelium all the way down to the endothelium. CQD-S were shown to enhance the penetration of FITC-dextran 150 kDa, suggesting that they could be used as efficient penetration enhancers for therapeutic delivery to the corneal endothelium.

A lipid nanoparticle platform for mRNA delivery through repurposing of cationic amphiphilic drugs.

Since the recent clinical approval of siRNA-based drugs and COVID-19 mRNA vaccines, the potential of RNA therapeutics for patient healthcare has become widely accepted. Lipid nanoparticles (LNPs) are currently the most advanced nanocarriers for RNA packaging and delivery. Nevertheless, the intracellular delivery efficiency of state-of-the-art LNPs remains relatively low and safety and immunogenicity concerns with synthetic lipid components persist, altogether rationalizing the exploration of alternative LNP compositions. In addition, there is an interest in exploiting LNP technology for simultaneous encapsulation of small molecule drugs and RNA in a single nanocarrier. Here, we describe how well-known tricyclic cationic amphiphilic drugs (CADs) can be repurposed as both structural and functional components of lipid-based NPs for mRNA formulation, further referred to as CADosomes. We demonstrate that selected CADs, such as tricyclic antidepressants and antihistamines, self-assemble with the widely-used helper lipid DOPE to form cationic lipid vesicles for subsequent mRNA complexation and delivery, without the need for prior lipophilic derivatization. Selected CADosomes enabled efficient mRNA delivery in various in vitro cell models, including easy-to-transfect cancer cells (e.g. human cervical carcinoma HeLa cell line) as well as hard-to-transfect primary cells (e.g. primary bovine corneal epithelial cells), outperforming commercially available cationic liposomes and state-of-the-art LNPs. In addition, using the antidepressant nortriptyline as a model compound, we show that CADs can maintain their pharmacological activity upon CADosome incorporation. Furthermore, in vivo proof-of-concept was obtained, demonstrating CADosome-mediated mRNA delivery in the corneal epithelial cells of rabbit eyes, which could pave the way for future applications in ophthalmology. Based on our results, the co-formulation of CADs, helper lipids and mRNA into lipid-based nanocarriers is proposed as a versatile and straightforward approach for the rational development of drug combination therapies.

Structure and surface dynamics of genomic DNA as probed with surface-enhanced Raman spectroscopy: Trace level sensing of nucleic acids extracted from plants.

In this work surface-enhanced Raman spectra of nucleic acids from in vitro grown Solanum tuberosum L. cultivars and populations (Buzau population, Lazarea population, Patraque d'Auvergne, RFA Roclas Clone 2.6 Ferma, Vitelotte Negresse, Roclas Clone C, Blue Congo) were measured with 532 nm laser line. Main surface-enhanced Raman modes of these DNAs have been analyzed. Also, DNA from two grapevine (Vitis vinifera L.) varieties were studied at acidic pHs by surface-enhanced Raman spectroscopy. Modified SERS intensities and wavenumber shifts of nucleic acids bands were observed upon lowering the pH, being a proof of binding affinity changes of DNA with silver nanoparticles (AgNPs) and of structural modifications induced at acidic pHs in DNA molecular groups. Furthermore, the (sub)picosecond surface dynamics of DNA extracted from leaf tissues of grapevine (Vitis vinifera L.) varieties was investigated. In this work, the bands full widths at half-maximum (FWHMs) have values in the wavenumber range from 8 to 34 cm-1. (Sub)picosecond molecular dynamics of DNA groups with global relaxation times between 0.31 ps - 1.33 ps has been found.

Review on combining surface-enhanced Raman spectroscopy and electrochemistry for analytical applications.

The discovery of surface enhanced Raman scattering (SERS) from an electrochemical (EC)-SERS experiment is known as a historic breakthrough. Five decades have passed and Raman spectroelectrochemistry (SEC) has developed into a common characterization tool that provides information about the electrode-electrolyte interface. Recently, this technique has been successfully explored for analytical purposes. EC was found to highly improve the performances of SERS sensors, providing, among others, controlled adsorption of analytes and increased reproducibility. In this review, we highlight the potential of EC-SERS sensors to be implemented for point-of-need (PON) analyses as miniaturized devices, and their ability to revolutionize fields like quality control, diagnosis or environmental and food safety. Important developments have been achieved in Raman spectroelectrochemistry, which now represents a promising alternative to conventional analytical methods and interests more and more researchers. The studies included in this review open endless possibilities for real-life EC-SERS analytical applications.

Acidic pH-responsive changes of DNA structure and surface dynamics as probed with ultrasensitive Raman spectroscopy.

In this work structural and (sub)picosecond surface dynamical changes of genomic DNA isolated from different medicinal plants (Hyssopus officinalis, Majorana hortensis, Melissa officinalis, Mentha piperita, Mentha piperita cv "Cristal", Monarda didyma and Matricaria chamomilla), as probed with surface-enhanced Raman spectroscopy (SERS), are discussed upon modifying the acidic pH of mixtures consisting of silver colloidal suspension and DNA samples, respectively. Binding affinity changes of DNA with silver NPs and nucleic acids protonation are supposed to take place upon lowering the pH. A small percentage of Hoogsteen GC basepairs was found in Mentha piperita cv "Cristal" DNA, at low acidic pH. As a general observation, the global relaxation times corresponding to different functional groups of the investigated genomic DNAs, respectively, show a decrease of their values upon lowering the pH.

Surface dynamics of genomic DNAs upon lowering the pH, in the presence of graphene/AgNPs-based SERS detection platform.

Graphene/AgNPs-based surface dynamics of native DNA functional groups at different acidic pH values was discussed using surface-enhanced Raman spectroscopy (SERS). Also, ab initio dynamics of Verlet type was investigated for nucleic acid nitrogenous bases adsorbed on a graphene surface, respectively. The experimental dynamical parameters were given in terms of full widths at half-maximum (FWHMs) and (sub)picosecond global relaxation times, associated with SERS bands. Furthermore, using density functional theory (DFT) as implemented in SIESTA and the velocity autocorrelation function (VACF), we have obtained the vibrational density of states (VDOS) for each of the four DNA bases placed on a pristine graphene layer. Graphical abstract Top: computed VbDOS for guanine. Bottom: Verlet temperature as a function of time.

Assessment of Genetic Relationships between Streptocarpus x hybridus V. Parents and F1 Progenies Using SRAP Markers and FT-IR Spectroscopy.

The genetic relationship among three Streptocarpus parents and twelve F1 hybrids was assessed using sequence-related amplified polymorphism (SRAP) molecular markers and Fourier-transform infrared (FT-IR) spectroscopy. Both methods were able to discriminate F1 hybrids and parents as revealed by cluster analysis. For hybrid identification, the type III SRAP marker was the most effective due to the presence of male-specific bands in the hybrids. Different behaviors in the biochemical variability of DNA samples have been observed by FT-IR spectral analysis, which might be attributed to the inherent nature of the genomic DNA from parents and their F1 progenies. Mantel test was also carried out to compare morphological, SRAP, and FT-IR results based on genetic distances. The highest correlation coefficient was found between morphological and SRAP marker distances (R = 0.607; p ≤ 0.022). A lower correlation was observed between the morphological and FT-IR distance matrix (R = 0.231; p ≤0.008). Moreover, a positive correlation was found between the distances generated with SRAP and FT-IR analyses (R = 0.026) but was not statistically significant. These findings show that both SRAP and FT-IR techniques combined with morphological descriptions can be used effectively for nonconventional breeding programs for Streptocarpus to obtain new and valuable varieties.

Metallic surface dynamics of genomic DNA and its nitrogenous bases: SERS assessment and theoretical considerations.

The dynamics of genomic DNA and its nucleobases at a silver surface were explored using surface-enhanced Raman spectroscopy (SERS) and ab initio Verlet-type dynamics, respectively. The bands observed had full widths at half-maximum (FWHMs) in the wavenumber range 10-29 cm-1. (Sub)picosecond molecular dynamics with global relaxation times of 0.37-1.06 ps were noted. Furthermore, the on-surface ab initio dynamics of the DNA bases were examined using DFT with a Verlet-type algorithm. The results attained for these ergodic dynamic systems describe real systems quite well and could therefore be correlated with corresponding experimental data.

Vibrational Relaxation of the Backbone and Base Modes in LacDNA Complexes by UV Resonance Raman Spectroscopy.

Vibrational band shape analysis through time correlation function concept is widely used to obtain experimental information on the molecular dynamics of medium-size molecules in different environments. Interesting details are revealed by extending this technique to biomolecules such as functional groups of the nucleic acids in media approaching the physiological conditions. In this work a study into the UV resonance Raman (UVRR) vibrational half bandwidths of functional groups in LacDNA, upon lowering the pH (pH 6.4, pH 3.45) and in the presence of Mn2+ and Ca2+ ions, respectively, was of interest. The corresponding global relaxation times have been derived. Also, the 793 cm-1 UVRR band, corresponding to ν (backbone O-P-O, dT) oscillator of LacDNA in aqueous solutions, was selected for band shape-analysis. Vibrational relaxation appears as the dominant relaxation process for this mode, with vibrational dephasing being the most efficient for this oscillator. Current theories developed for vibrational dephasing have been applied to this profile, and relevant relaxation parameters have been obtained and discussed. To our knowledge this is the first study on DNA oligomers vibrational band shape analysis through time correlation function concept.

Immunotherapy in Peripheral Neuropathies.

Immunotherapy has been investigated in a small subset of peripheral neuropathies, including an acute one, Guillain-Barré syndrome, and 3 chronic forms: chronic inflammatory demyelinating polyradiculoneuropathy, multifocal motor neuropathy, and neuropathy associated with IgM anti-myelin-associated glycoprotein. Several experimental studies and clinical data are strongly suggestive of an immune-mediated pathogenesis. Either cell-mediated mechanisms or antibody responses to Schwann cell, compact myelin, or nodal antigens are considered to act together in an aberrant immune response to cause damage to peripheral nerves. Immunomodulatory treatments used in these neuropathies aim to act at various steps of this pathogenic process. However, there are many phenotypic variants and, consequently, there is a significant difference in the response to immunotherapy between these neuropathies, as well as a need to improve our knowledge and long-term management of chronic forms.

Structural Changes Induced in Grapevine (Vitis vinifera L.) DNA by Femtosecond IR Laser Pulses: A Surface-Enhanced Raman Spectroscopic Study.

In this work, surface-enhanced Raman spectra of ten genomic DNAs extracted from leaf tissues of different grapevine (Vitis vinifera L.) varieties, respectively, are analyzed in the wavenumber range 300-1800 cm-1. Furthermore, structural changes induced in grapevine genomic nucleic acids upon femtosecond (170 fs) infrared (IR) laser pulse irradiation (λ = 1100 nm) are discussed in detail for seven genomic DNAs, respectively. Surface-enhanced Raman spectroscopy (SERS) signatures, vibrational band assignments and structural characterization of genomic DNAs are reported for each case. As a general observation, the wavenumber range between 1500 and 1660 cm-1 of the spectra seems to be modified upon laser treatment. This finding could reflect changes in the base-stacking interactions in DNA. Spectral shifts are mainly attributed to purines (dA, dG) and deoxyribose. Pyrimidine residues seem to be less affected by IR femtosecond laser pulse irradiation. Furthermore, changes in the conformational properties of nucleic acid segments are observed after laser treatment. We have found that DNA isolated from Feteasca Neagra grapevine leaf tissues is the most structurally-responsive system to the femtosecond IR laser irradiation process. In addition, using unbiased computational resources by means of principal component analysis (PCA), eight different grapevine varieties were discriminated.

Surface-enhanced Raman spectroscopy of genomic DNA from in vitro grown tomato (Lycopersicon esculentum Mill.) cultivars before and after plant cryopreservation.

In this work the surface-enhanced Raman scattering (SERS) spectra of five genomic DNAs from non-cryopreserved control tomato plants (Lycopersicon esculentum Mill. cultivars Siriana, Darsirius, Kristin, Pontica and Capriciu) respectively, have been analyzed in the wavenumber range 400-1800 cm(-1). Structural changes induced in genomic DNAs upon cryopreservation were discussed in detail for four of the above mentioned tomato cultivars. The surface-enhanced Raman vibrational modes for each of these cases, spectroscopic band assignments and structural interpretations of genomic DNAs are reported. We have found, that DNA isolated from Siriana cultivar leaf tissues suffers the weakest structural changes upon cryogenic storage of tomato shoot apices. On the contrary, genomic DNA extracted from Pontica cultivar is the most responsive system to cryopreservation process. Particularly, both C2'-endo-anti and C3'-endo-anti conformations have been detected. As a general observation, the wavenumber range 1511-1652 cm(-1), being due to dA, dG and dT residues seems to be influenced by cryopreservation process. These changes could reflect unstacking of DNA bases. However, not significant structural changes of genomic DNAs from Siriana, Darsirius and Kristin have been found upon cryopreservation process of tomato cultivars. Based on this work, specific plant DNA-ligand interactions or accurate local structure of DNA in the proximity of a metallic surface, might be further investigated using surface-enhanced Raman spectroscopy.

Subpicosecond surface dynamics in genomic DNA from in vitro-grown plant species: a SERS assessment.

In this work the surface-enhanced Raman total half band widths of seven genomic DNAs from leaves of chrysanthemum (Dendranthema grandiflora Ramat.), common sundew (Drosera rotundifolia L.), edelweiss (Leontopodium alpinum Cass), Epilobium hirsutum L., Hypericum richeri ssp. transsilvanicum (Celak) Ciocârlan, rose (Rosa x hybrida L.) and redwood (Sequoia sempervirens D. Don. Endl.) have been measured. We have shown that surface-enhanced Raman spectroscopy (SERS) can be used to study the fast subpicosecond dynamics of DNA in the proximity of a metallic surface. The dependencies of the total half band widths and the global relaxation times, on the DNA molecular subgroup structure and on the type of genomic DNA, are reported. In our study, the full widths at half-maximum (FWHMs) for the SERS bands of genomic DNAs from different leaf tissues are typically in the wavenumber range from 15 to 55 cm(-1). Besides, it can be observed that molecular relaxation processes studied in this work have a global relaxation time smaller than 0.71 ps and larger than 0.19 ps. A comparison between different ranges of FT-Raman and SERS band parameters, respectively, corresponding to DNA extracted from leaf tissues is given. It is shown that the interaction between DNA and a metallic surface has the potential to lead to a shortening of the global relaxation times, as compared with molecular dynamics in solution. We have found that the surface dynamics of molecular subgroups in plant DNA is, in some cases, about two times faster than the solution dynamics of nucleic acids. This can be rationalized in a qualitative manner by invoking the complex landscape of the interaction energy between the molecule and the silver surface.

DFT investigation of the vibrational properties of GC Watson-Crick and Hoogsteen base pairs in the presence of Mg²âº, Ca²âº, and Cu²âº ions.

The binding effects of Mg²âº, Ca²âº, and Cu²âº ions on the vibrational properties of guanine-cytosine base pairs have been performed using density functional theory investigations. Both Watson-Crick and Hoogsteen configurations of the base pairs were investigated. In Watson-Crick configuration, the metal was coordinated at N7 atom of guanine, while in the case of Hoogsteen configuration, the coordination is at N3 atom of guanine. We have pointed out the geometric properties of the metal-GC base pairs structure, as well as the vibrational bands that can be used to detect the presence of metallic ions in the Watson-Crick and Hoogsteen GC structures. For the geometric models used by us, the vibrational amplitudes of metallic atoms were stronger for wavenumbers lower than 500 cm⁻¹. This suggests that in the experimental studies on DNA the presence of the three metallic atoms (Mg, Ca, and Cu) can be explicitly detected at low frequencies.

The influence of anharmonic and solvent effects on the theoretical vibrational spectra of the guanine-cytosine base pairs in Watson-Crick and Hoogsteen configurations.

The theoretical IR and Raman spectra of the guanine-cytosine DNA base pairs in Watson-Crick and Hoogsteen configurations were computed using DFT method with M06-2X meta-hybrid GGA exchange-correlation functional, including the anharmonic corrections and solvent effects. The results for harmonic frequencies and their anharmonic corrections were compared with our previously calculated values obtained with the B3PW91 hybrid GGA functional. Significant differences were obtained for the anharmonic corrections calculated with the two different DFT functionals, especially for the stretching modes, while the corresponding harmonic frequencies did not differ considerable. For the Hoogtseen case the H⁺ vibration between the G-C base pair can be characterized as an asymmetric Duffing oscillator and therefore unrealistic anharmonic corrections for normal modes where this proton vibration is involved have been obtained. The spectral modification due to the anharmonic corrections, solvent effects and the influence of sugar-phosphate group for the Watson-Crick and Hoogsteen base pair configurations, respectively, were also discussed. For the Watson-Crick case also the influence of the stacking interaction on the theoretical IR and Raman spectra was analyzed. Including the anharmonic correction in our normal mode analysis is essential if one wants to obtain correct assignments of the theoretical frequency values as compared with the experimental spectra.