Fourier Transform Infrared Radiation (FTIR) spectroscopy is one of the most powerful methods for the detection of gaseous constituents, aerosols, and dust in planetary atmospheres. Infrared spectroscopy plays an important role in searching for biomarkers, organics and biological substances in the Universe. The possibility of detection and identifications with FTIR spectrometer of bio-aerosol spores (Bacillus atrophaeus var. globigii=BG) in the atmosphere is discussed in this paper. We describe the results of initial spectral measurements performed in the laboratory and in the field. The purpose of these experiments was to detect and to identify bio-aerosol spores in two conditions: 1) In a closed chamber where the thermal contrast between the background and aerosols was large, and 2) In open air where the thermal contrast between the background and aerosols was small. The extinction spectrum of BG spores was deduced by comparing our measurements with models, and other measurements known from the literature. Our theoretical and experimental studies indicate that, during passive remote sensing measurements, it is difficult—but possible to detect and to identify bio-aerosol clouds by their spectral signatures. The simple spectral analysis described in the paper can be useful for the detection of various kinds of trace aerosols—not only in the Earth’s atmosphere, but also during planetary missions in the environments of other astronomical objects such as planets, comets etc. We expect that the interpretation of data from spectrometric sounding of Venus and Mars during the current missions Mars and Venus Express, and later during the Rosetta mission will benefit from our experimental work and numerical modelling.
Bio-aerosols; Spectroscopy; Remote sensing of the atmosphere; Astrobiology
Commercially, extra virgin olive oil (EVOO) is subjected to be adulterated with low-price oils having similar color to EVOO. Fourier transform infrared (FTIR) spectroscopy combined with chemometrics has been successfully used for classification and quantification of corn (CO) and sunflower oils (SFOs) in EVOO sets. The combined frequency regions of 3027–3000, 1076–860, and 790–698 cm−1 were used for classification and quantification of CO in EVOO; meanwhile, SFO was analyzed using frequency regions of 3025–3000 and 1400–985 cm−1. Discriminant analysis can make classification of pure EVOO and EVOO adulterated with CO and SFO with no misclassification reported. The presence of CO in EVOO was determined with the aid of partial least square calibration using FTIR normal spectra. The calibration and validation errors obtained in CO's quantification are 0.404 and 1.13%, respectively. Meanwhile, the first derivative FTIR spectra and PLS calibration model were preferred for quantification of SFO in EVOO with high coefficient of determination (R2) and low errors, either in calibration or in validation sample sets.
Differentiation of the species within the genus Listeria is important for the food industry but only a few reliable methods are available so far. While a number of studies have used Fourier transform infrared (FTIR) spectroscopy to identify bacteria, the extraction of complex pattern information from the infrared spectra remains difficult. Here, we apply artificial neural network technology (ANN), which is an advanced multivariate data-processing method of pattern analysis, to identify Listeria infrared spectra at the species level. A hierarchical classification system based on ANN analysis for Listeria FTIR spectra was created, based on a comprehensive reference spectral database including 243 well-defined reference strains of Listeria monocytogenes, L. innocua, L. ivanovii, L. seeligeri, and L. welshimeri. In parallel, a univariate FTIR identification model was developed. To evaluate the potentials of these models, a set of 277 isolates of diverse geographical origins, but not included in the reference database, were assembled and used as an independent external validation for species discrimination. Univariate FTIR analysis allowed the correct identification of 85.2% of all strains and of 93% of the L. monocytogenes strains. ANN-based analysis enhanced differentiation success to 96% for all Listeria species, including a success rate of 99.2% for correct L. monocytogenes identification. The identity of the 277-strain test set was also determined with the standard phenotypical API Listeria system. This kit was able to identify 88% of the test isolates and 93% of L. monocytogenes strains. These results demonstrate the high reliability and strong potential of ANN-based FTIR spectrum analysis for identification of the five Listeria species under investigation. Starting from a pure culture, this technique allows the cost-efficient and rapid identification of Listeria species within 25 h and is suitable for use in a routine food microbiological laboratory.
There is a requirement for a noninvasive technique to monitor stem cell differentiation. Several candidates based on optical spectroscopy are discussed in this review: Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and coherent anti-Stokes Raman scattering (CARS) microscopy. These techniques are briefly described, and the ability of each to distinguish undifferentiated from differentiated cells is discussed. FTIR spectroscopy has demonstrated its ability to distinguish between stem cells and their derivatives. Raman spectroscopy shows a clear reduction in DNA and RNA concentrations during embryonic stem cell differentiation (agreeing with the well-known reduction in the nucleus to cytoplasm ratio) and also shows clear increases in mineral content during differentiation of mesenchymal stem cells. CARS microscopy can map these DNA, RNA, and mineral concentrations at high speed, and Mutliplex CARS spectroscopy/microscopy is highlighted as the technique with most promise for future applications.
This paper demonstrates the use of attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to detect microbial metabolic products on carbonate mineral surfaces. By creating an ATR-FTIR spectral database for specific organic acids using ATR-FTIR spectroscopy we were able to distinguish metabolic acids on calcite surfaces following Escherichia coli growth. The production of these acids by E. coli was verified using high-performance liquid chromatography with refractive index detection. The development of this technique has allowed us to identify microbial metabolic products on carbonate surfaces in nutrient-limited cave environments.
Two important plant pathogenic bacteria Acidovorax oryzae and Acidovorax citrulli are closely related and often not easy to be differentiated from each other, which often resulted in a false identification between them based on traditional methods such as carbon source utilization profile, fatty acid methyl esters, and ELISA detection tests. MALDI-TOF MS and Fourier transform infrared (FTIR) spectra have recently been successfully applied in bacterial identification and classification, which provide an alternate method for differentiating the two species.
Characterization and comparison of the 10 A. oryzae strains and 10 A. citrulli strains were performed based on traditional bacteriological methods, MALDI-TOF MS, and FTIR spectroscopy. Our results showed that the identity of the two closely related plant pathogenic bacteria A. oryzae and A. citrulli was able to be confirmed by both pathogenicity tests and species-specific PCR, but the two species were difficult to be differentiated based on Biolog and FAME profile as well as 16 S rRNA sequence analysis. However, there were significant differences in MALDI-TOF MS and FTIR spectra between the two species of Acidovorax. MALDI-TOF MS revealed that 22 and 18 peaks were specific to A. oryzae and A. citrulli, respectively, while FTIR spectra of the two species of Acidovorax have the specific peaks at 1738, 1311, 1128, 1078, 989 cm-1 and at 1337, 968, 933, 916, 786 cm-1, respectively.
This study indicated that MALDI-TOF MS and FTIR spectra may give a new strategy for rapid bacterial identification and differentiation of the two closely related species of Acidovorax.
The objective of this study was to investigate the influence of type of cross-linking method used on the properties of ambroxol hydrochloride microspheres such as encapsulation efficiency, particle size, and drug release. Microspheres were prepared by solvent evaporation technique using chitosan as a matrix-forming agent and cross-linked using formaldehyde and heat treatment. Morphological and physicochemical properties of microspheres were then investigated by scanning electron microscopy (SEM), X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and Fourier-transform infrared spectroscopy (FTIR) spectroscopy. The cross-linking of chitosan takes place at the free amino group because of formation of imine bond as evidenced by FTIR. The DSC, XRD, and FTIR analysis showed that chitosan microspheres cross linked by heating were superior in properties and performance as compared to the microspheres cross-linked using formaldehyde. SEM results revealed that heat-treated microspheres were spherical, discrete having smooth, and porous structure. The particle size and encapsulation efficiencies of the prepared chitosan microspheres ranged between 10.83–24.11 μm and 39.73μ80.56%, respectively. The drug release was extended up to 12 h, and the kinetics of the drug release was obeying Higuchi kinetic proving diffusion-controlled drug release.
Ambroxol hydrochloride; chitosan microspheres; cross-linking agents
Survival time for lung cancer is poor with over 90% of patients dying within five years of diagnosis primarily due to detection at late stage. The main objective of this study was to evaluate Fourier transform infrared spectroscopy (FTIR) as a high throughput and cost effective method for identifying biochemical changes in sputum as biomarkers for detection of lung cancer.
Sputum was collected from 25 lung cancer patients in the Medlung observational study and 25 healthy controls. FTIR spectra were generated from sputum cell pellets using infrared wavenumbers within the 1800 to 950 cm-1 "fingerprint" region.
A panel of 92 infrared wavenumbers had absorbances significantly different between cancer and normal sputum spectra and were associated with putative changes in protein, nucleic acid and glycogen levels in tumours. Five prominent significant wavenumbers at 964 cm-1, 1024 cm-1, 1411 cm-1, 1577 cm-1 and 1656 cm-1 separated cancer spectra from normal spectra into two distinct groups using multivariate analysis (group 1: 100% cancer cases; group 2: 92% normal cases). Principal components analysis revealed that these wavenumbers were also able to distinguish lung cancer patients who had previously been diagnosed with breast cancer. No patterns of spectra groupings were associated with inflammation or other diseases of the airways.
Our results suggest that FTIR applied to sputum might have high sensitivity and specificity in diagnosing lung cancer with potential as a non-invasive, cost-effective and high-throughput method for screening.
A classification system based on Fourier transform infrared (FTIR) spectroscopy combined with artificial neural network analysis was designed to differentiate 12 serovars of Listeria monocytogenes using a reference database of 106 well-defined strains. External validation was performed using a test set of another 166 L. monocytogenes strains. The O antigens (serogroup) of 164 strains (98.8%) could be identified correctly, and H antigens were correctly determined in 152 (91.6%) of the test strains. Importantly, 40 out of 41 potentially epidemic serovar 4b strains were unambiguously identified. FTIR analysis is superior to PCR-based systems for serovar differentiation and has potential for the rapid, simultaneous identification of both species and serovar of an unknown Listeria isolate by simply measuring a whole-cell infrared spectrum.
The photosystem II reaction center mediates the light-induced transfer of electrons from water to plastoquinone, with concomitant production of O2. Water oxidation chemistry occurs in the oxygen-evolving complex (OEC), which consists of an inorganic Mn4CaO5 cluster and its surrounding protein matrix. Light-induced Fourier transform infrared (FTIR) difference spectroscopy has been successfully used to study the molecular mechanism of photosynthetic water oxidation. This powerful technique has enabled the characterization of the dynamic structural changes in active water molecules, the Mn4CaO5 cluster, and its surrounding protein matrix during the catalytic cycle. This mini-review presents an overview of recent important progress in FTIR studies of the OEC and implications for revealing the molecular mechanism of photosynthetic water oxidation.
photosystem II; oxygen evolution; FTIR; manganese cluster; infrared spectroscopy
Drinking water quality management requires early warning tools which enable water supply companies to detect quickly and to forecast degradation of the microbial quality of drinking water during its transport throughout distribution systems. This study evaluated the feasibility of assessing, in real time, drinking water biostability by monitoring in situ the evolution of the attenuated total reflectance-Fourier transform infrared (ATR-FTIR) fingerprint of a nascent reference biofilm exposed to water being tested. For this purpose, the responses of nascent Pseudomonas fluorescens biofilms to variations in the dissolved organic carbon (DOC) level in tap water were monitored in situ and in real time by ATR-FTIR spectroscopy. Nascent P. fluorescens biofilms consisting of a monolayer of bacteria were formed on the germanium crystal of an ATR flowthrough cell by pumping bacterial suspensions in Luria-Bertani (LB) medium through the cell. Then they were exposed to a continuous flow of dechlorinated sterile tap water supplemented with appropriate amounts of sterile LB medium to obtain DOC concentrations ranging from 1.5 to 11.8 mg/liter. The time evolution of infrared bands related to proteins, polysaccharides, and nucleic acids clearly showed that changes in the DOC concentration resulted in changes in the nascent biofilm ATR-FTIR fingerprint within 2 h after exposure of the biofilm to the water being tested. The initial bacterial attachment, biofilm detachment, and regrowth kinetics determined from changes in the areas of bands associated with proteins and polysaccharides were directly dependent on the DOC level. Furthermore, they were consistent with bacterial adhesion or growth kinetic models and extracellular polymeric substance overproduction or starvation-dependent detachment mechanisms.
Direct detection of saponins in medicinal plants using Fourier Transform Infrared (FTIR) spectroscopy is reported in this paper. Crude dry plant powders were mixed with potassium bromide (KBr) powder and compressed to a thin pellet for infrared examination. FTIR spectra of the test samples showed -OH, -C=O, C-H, and C=C absorptions characteristic of oleanane triterpenoid saponins. The C-O-C absorptions indicated glycoside linkages to the sapogenins. Phytochemical analysis confirmed the presence of saponins in the tested specimens. Entada leptostachya was used as a reference sample. Dry plant powder was extracted sequentially with hexane, dichloromethane, ethyl acetate and methanol. FTIR spectra of the reference sample powder and its organic solvent extracts showed characteristic saponin absorption peaks. These results indicated that direct detection of saponins in medicinal plants was possible by infrared analysis. Lengthy exhaustive chemical analyses necessary for detection of saponins could be avoided.
Medicinal plants; saponins; infrared spectra; potassium bromide; glycoside
An extremely well-preserved dinosaur (Cf. Edmontosaurus sp.) found in the Hell Creek Formation (Upper Cretaceous, North Dakota) retains soft-tissue replacement structures and associated organic compounds. Mineral cements precipitated in the skin apparently follow original cell boundaries, partially preserving epidermis microstructure. Infrared and electron microprobe images of ossified tendon clearly show preserved mineral zonation, with silica and trapped carbon dioxide forming thin linings on Haversian canals within apatite. Furthermore, Fourier transform infrared spectroscopy (FTIR) of materials recovered from the skin and terminal ungual phalanx suggests the presence of compounds containing amide groups. Amino acid composition analyses of the mineralized skin envelope clearly differ from the surrounding matrix; however, intact proteins could not be obtained using protein mass spectrometry. The presence of endogenously derived organics from the skin was further demonstrated by pyrolysis gas chromatography mass spectrometry (Py-GCMS), indicating survival and presence of macromolecules that were in part aliphatic (see the electronic supplementary material).
hadrosaur; Hell Creek; soft tissue
Four cost effective organoclays were synthesized, characterized, and studied for the sorption of hydrophobic compounds (edible oil/grease and hydrocarbon oil) from aqueous solutions. Organoclays were prepared by cation exchange reaction of lattice ions (present onto the surface of laterite and bentonite clay minerals) with two surfactants, hexadecyl trimethyl ammonium chloride (HDTMA-Cl) and tetradecyl trimethyl ammonium bromide (TDTMA-Br). Fourier transform infrared spectroscopy and scanning electron microscopy were used for the characterization of synthesized organoclays. It was found that the amount of surfactant loading and the nature of the surfactant molecules used in the syntheses of organoclay strongly affect the sorption capacity of the clay mineral. Further, it was found that both the laterite and bentonite based organoclays efficiently removed the edible and hydrocarbon oil content from lab prepared emulsions; however, the adsorption capacity of clay mineral was greatly influenced by the nature of hydrophobic compounds as well.
Fourier Transform InfraRed (FTIR) spectroscopy is a powerful and rapid technique for analyzing cell wall components and putative cross-links, which is able to non-destructively recognize polymers and functional groups and provide abundant information about their in muro organization. FTIR spectroscopy has been reported to be a useful tool for monitoring cell wall changes occurring in muro as a result of various factors, such as growth and development processes, mutations or biotic and abiotic stresses. This mini-review examines the use of FTIR spectroscopy in conjunction with multivariate analyses to monitor cell wall changes related to (1) the exposure of diverse plant materials to cellulose biosynthesis inhibitors (CBIs) and (2) the habituation/dehabituation of plant cell cultures to this kind of herbicides. The spectra analyses show differences not only regarding the inhibitor, but also regarding how long cells have been growing in its presence.
FTIR; cellulose biosynthesis inhibitor; habituation/dehabituation
The purpose of this study was to characterize the variation in biochemical composition of 89 strains of Listeria monocytogenes with different susceptibilities towards sakacin P, using Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. The strains were also analyzed using amplified fragment length polymorphism (AFLP) analysis. Based on their susceptibilities to sakacin P, the 89 strains have previously been divided into two groups. Using the FTIR spectra and AFLP data, the strains were basically differentiated into the same two groups. Analyses of the FTIR and Raman spectra revealed that the strains in the two groups contained differences in the compositions of carbohydrates and fatty acids. The relevance of the variation in the composition of carbohydrates with respect to the variation in the susceptibility towards sakacin P for the L. monocytogenes strains is discussed.
Fatty liver or steatosis is a frequent histopathological change. It is a precursor for steatohepatitis that may progress to cirrhosis and in some cases to hepatocellular carcinoma. In this study we addressed the in situ composition and distribution of biochemical compounds on tissue sections of steatotic liver using both synchrotron FTIR (Fourier transform infrared) and ToF-SIMS (time of flight secondary ion mass spectrometry) microspectroscopies. FTIR is a vibrational spectroscopy that allows investigating the global biochemical composition and ToF-SIMS lead to identify molecular species in particular lipids. Synchrotron FTIR microspectroscopy demonstrated that bands linked to lipid contribution such as -CH3 and -CH2 as well as esters were highly intense in steatotic vesicles. Moreover, a careful analysis of the -CH2 symmetric and anti-symmetric stretching modes revealed a slight downward shift in spectra recorded inside steatotic vesicles when compared to spectra recorded outside, suggesting a different lipid environment inside the steatotic vesicles. ToF-SIMS analysis of such steatotic vesicles disclosed a selective enrichment in cholesterol as well as in diacylglycerol (DAG) species carrying long alkyl chains. Indeed, DAG C36 species were selectively localized inside the steatotic vesicles whereas DAG C30 species were detected mostly outside. Furthermore, FTIR detected a signal corresponding to olefin (C = C, 3000-3060 cm−1) and revealed a selective localization of unsaturated lipids inside the steatotic vesicles. ToF-SIMS analysis definitely demonstrated that DAG species C30, C32, C34 and C36 carrying at least one unsaturated alkyl chain were selectively concentrated into the steatotic vesicles. On the other hand, investigations performed on the non-steatotic part of the fatty livers have revealed important changes when compared to the normal liver. Although the non-steatotic regions of fatty livers exhibited normal histological aspect, IR spectra demonstrated an increase in the lipid content and ToF-SIMS detected small lipid droplets corresponding most likely to the first steps of lipid accretion.
The aim of this study was to characterize the penicillin-loaded microbeads composed of alginate and octenyl succinic anhydride (OSA) starch prepared by ionotropic pregelation with calcium chloride and to evaluate their in vitro drug delivery profile. The beads were characterized by size, scanning electron microscopy (SEM), zeta potential, swelling behavior, and degree of erosion. Also, the possible interaction between penicillin and biopolymers was investigated by differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), and Fourier transform infrared (FTIR) analysis. The SEM micrograph results indicated a homogeneous drug distribution in the matrix. Also, based on thermal analyses (TGA/DSC), interactions were detected between microbead components. Although FTIR spectra of penicillin-loaded microbeads did not reveal the formation of new chemical entities, they confirmed the chemical drug stability. XRD patterns showed that the incorporated crystalline structure of penicillin did not significantly alter the primarily amorphous polymeric network. In addition, the results confirmed a prolonged penicillin delivery system profile. These results imply that alginate and OSA starch beads can be used as a suitable controlled-release carrier for penicillin.
Methods for imaging of nanocomposites based on X-ray, electron, tunneling or force microscopy provide information about the shapes of nanoparticles; however, all of these methods fail on chemical recognition. Neither do they allow local identification of mineral type. We demonstrate that infrared near-field microscopy solves these requirements at 20 nm spatial resolution, highlighting, in its first application to natural nanostructures, the mineral particles in shell and bone. "Nano-FTIR" spectral images result from Fourier-transform infrared (FTIR) spectroscopy combined with scattering scanning near-field optical microscopy (s-SNOM). On polished sections of Mytilus edulis shells we observe a reproducible vibrational (phonon) resonance within all biocalcite microcrystals, and distinctly different spectra on bioaragonite. Surprisingly, we discover sparse, previously unknown, 20 nm thin nanoparticles with distinctly different spectra that are characteristic of crystalline phosphate. Multicomponent phosphate bands are observed on human tooth sections. These spectra vary characteristically near tubuli in dentin, proving a chemical or structural variation of the apatite nanocrystals. The infrared band strength correlates with the mineral density determined by electron microscopy. Since nano-FTIR sensitively responds to structural disorder it is well suited for the study of biomineral formation and aging. Generally, nano-FTIR is suitable for the analysis and identification of composite materials in any discipline, from testing during nanofabrication to even the clinical investigation of osteopathies.
biomineralization; chemical mapping; infrared spectroscopy; nanocrystals; optical near-field microscopy
Background and Objectives
The significant rise in food borne infections is mainly caused by Campylobacter spp., Salmonella serovars and Verotoxigenic Escherichia coli. As the emerging food borne pathogens cause disease, more studies have been conducted for rapid detection of these pathogens. The combination of immunomagnetic separation and polymerase chain reaction (IMS-PCR) is the most accurate and rapid test preferred by almost every researcher. Fourier Transform Infrared Spectroscopy (FTIR) is preferred for being a new, user friendly and rapid technique in microbiological analyses. The main aim of this study is to detect application of IMS-FTIR for Salmonella identification from foods in a short time with a higher sensitivity.
Materials and Methods
Conventional Culture Technique (CC), IMS-CC, IMS-PCR and IMS-FTIR techniques were compared with each other for rapid detection in artificially contaminated minced beef with Salmonella Typhimurium, as of the 2nd, 4th and 8th hours of contamination. The method was evaluated in different food matrices and sensitivity, specifity and overall recovery was calculated.
The results indicate that IMS-FTIR can detect S. Typhimurium as of the 8th hour with sensitivity of 95.6667, accuracy of 91.69329, false positive ratio of 0.04333 and overall recovery of 95.66%.
It can be suggested that the IMS-FTIR method is capable of detecting S.Typhimurium in a short time with lower cost.
FTIR; IMS; Salmonella; PCR; Meat
Cisplatin is a common chemotherapeutic agent that used for treatment of many solid cancers. Rapid identification of chemotherapy resistance is very important and may lead to effective treatment plan. Spectroscopy techniques, such as infrared spectroscopy, which are sensitive to biochemical composition of samples, have shown potentials to discriminate tissues. Developing in Fourier transform infrared (FTIR) as a diagnostic tool support conventional technique in investigating cell phenotype. By this goal three different cell lines, two cisplatin resistant OV2008-DDP (C13) and A2780-CP ovarian cell lines and one cisplatin sensitive A2780 cell line were investigated by FTIR spectroscopy. Data were subjected to principle component analysis (PCA) to obtain FTIR pattern for cisplatin resistance. Using FTIR spectroscopy on these cells in the range of 400-4000 cm-1 was shown dramatic change in cells. Results shows that Cisplatin resistance pattern is characterized in spectrum with the alteration of conformation in secondary structure of proteins and a shift toward the high wave numbers of CH2 stretching vibration. The FTIR data set between 1000 and 3000 cm-1 could be consumed as biochemical typicality spectra among resistant and sensitive cell lines while correctly classified by PCA model. Our work supports the promise of PCA analysis of FTIR data as a powerful combined approach for the development of automated methods to recognize resistant to cisplatin in experimental cell lines. One of the advantages of this tool is to investigate the resistant percent of cancer cells .Such technique may bring new tool in cancer diagnosis and stage definition in cancerous tissues.
Drug resistant; Fourier transform infrared; Principle component analysis; Feature extraction; Cell line
Porous Si is a nanostructured material that is of interest for molecular and cell-based biosensing, drug delivery, and tissue engineering applications. Surface chemistry is an important factor determining the stability of porous Si in aqueous media, its affinity for various biomolecular species, and its compatibility with tissues. In this study, the attachment and viability of a primary cell type to porous Si samples containing various surface chemistries is reported, and the ability of the porous Si films to retain their optical reflectivity properties relevant to molecular biosensing is assessed. Four chemical species grafted to the porous Si surface are studied: silicon oxide (via ozone oxidation), dodecyl (via hydrosilylation with dodecene), undecanoic acid (via hydrosilylation with undecylenic acid), and oligo(ethylene) glycol (via hydrosilylation with undecylenic acid followed by an oligo(ethylene) glycol coupling reaction). Fourier Transform Infrared (FTIR) spectroscopy and contact angle measurements are used to characterize the surface. Adhesion and short-term viability of primary rat hepatocytes on these surfaces, with and without pre-adsorption of collagen type I, are assessed using vital dyes (calcein-AM and ethidium homodimer I). Cell viability on undecanoic acid-terminated porous Si, oxide-terminated porous Si, and oxide-terminated flat (non-porous) Si are monitored by quantification of albumin production over the course of 8 days. The stability of porous Si thin films after 8 days in cell culture is probed by measuring the optical interferometric reflectance spectra. Results show that hepatocytes adhere better to surfaces coated with collagen, and that chemical modification does not exert a deleterious effect on primary rat hepatocytes. The hydrosilylation chemistry greatly improves the stability of porous Si in contact with cultured primary cells while allowing cell coverage levels comparable to standard culture preparations on tissue culture polystyrene.
Mucoadhesive polymeric (carbopol 934) suspension of ciprofloxacin was prepared by ultrasonication and optimized with the aim of developing an oral controlled release gastro-retentive dosage form. The qualitative analysis of the formulation was performed by fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray powder diffraction (XRD), and scanning electron microscopy (SEM) analyses. FTIR (400 cm-1 to 4000 cm-1 region) and Raman (140 to 2400 cm-1 region) Spectroscopic studies were carried out and the spectra were used for interpretation. XRD data of pure drug, polymer and the formulation were obtained using a powder diffractometer scanned from a Bragg's angle (2θ) of 10° to 70°. The dispersion of the particle was observed using SEM techniques. The particle size distribution and aspect ratio of particles in the polymeric suspension were obtained from SEM image analysis. The results from FTIR and Raman spectroscopic analyses suggested that, in formulation, the carboxylic groups of ciprofloxacin and hydroxyl groups of C934 undergo a chemical interaction leading to esterification and hydrogen bonding. The XRD data suggested that the retention of crystalline nature of ciprofloxacin in the formulation would lead to increase in stability and drug loading; decrease in solubility; and delay in release of the drug from polymeric suspension with better bioavailability and penetration capacity. The SEM image analysis indicated that, in the formulation maximum particles were having aspect ratio from 2 to 4 and standard deviation was very less which provided supporting evidences for homogeneous, uniformly dispersed, stable controlled release ciprofloxacin suspension which would be pharmaceutically acceptable.
Carbopol 934; ciprofloxacin; mucoadhesive suspension
The purpose of this investigation was to develop solid dispersion (SD) formulation of cyclosporine (CyA) using polyethylene glycol (PEG-6000) to enhance its dissolution rate followed by nondestructive method for the prediction of both drug and carrier. SD formulations were prepared by varying the ratio of CyA and PEG-6000 by solvent evaporation technique and characterized by dissolution, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), powder X-ray diffraction (PXRD), near infrared (NIR) and near infrared chemical imaging (NIR-CI). Dissolution data revealed enhanced dissolution of CyA when compared with pure CyA. DSC results showed that the crystallinity of PEG-6000 has decreased as indicated by decrease in the enthalpy of fusion and melting peak in the formulations. FTIR data demonstrated no chemical interaction between drug and carrier. The surface morphology of SD formulations was similar to PEG-6000 particle. NIR-CI disclosed homogeneity of SD matrix as indicated by symmetrical histograms with smaller values of skewness. Similar to NIR, a multivariate peak evaluation with principal component analysis and partial least square (PLS) were carried out with PXRD spectral data. PLS models with both techniques showed good correlation coefficient and smaller value of root mean square of errors. The accuracy of model for predicting CyA and PEG-6000 in NIR and PXRD data were 5.22%, 5.35%, 5.27%, and 2.10%, respectively. In summary, chemometric applications of non-destructive method sensors provided a valuable means of characterization and estimation of drug and carrier in the novel formulations.
cyclosporin; NIR; PEG-6000; PXRD; solid dispersion
In this paper, we report a simple, rapid, and robust method to synthesize surface-enhanced Raman-scattered gold nanoparticles (GNPs) based on green chemistry. Vitis vinifera L. extract was used to synthesize noncytotoxic Raman-active GNPs. These GNPs were characterized by ultraviolet-visible spectroscopy, dynamic light-scattering, Fourier-transform infrared (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. The characteristic surface plasmon-resonance band at ~ 528 nm is indicative of spherical particles, and this was confirmed by TEM. The N–H and C–O stretches in FTIR spectroscopy indicated the presence of protein molecules. The predominant XRD plane at (111) and (200) indicated the crystalline nature and purity of GNPs. GNPs were stable in the buffers used for biological studies, and exhibited no cytotoxicity in noncancerous MIO-M1 (Müller glial) and MDA-MB-453 (breast cancer) cell lines. The GNPs exhibited Raman spectral peaks at 570, 788, and 1,102 cm−1. These new GNPs have potential applications in cancer diagnosis, therapy, and ultrasensitive biomarker detection.
GNPs; SERS; SPR; Vitis vinifera L.; stability