FT-IR spectroscopy of lipoproteins--a comparative study

High internal phase Pickering emulsions stabilized by egg yolk-carboxymethyl cellulose as an age-friendly dysphagia food: Tracking the dynamic transition from co-solubility to coacervates

Although protein-polysaccharide complexes with different phase behaviors all show potential for stabilizing high internal phase Pickering emulsions (HIPPEs), it is not clarified which aggregation state is more stable and age-friendly. In this study, we investigated and compared the stability and age friendliness of HIPPEs stabilized with egg yolk and carboxymethyl cellulose (EYCMC) in different phase behaviors. The results revealed differences in particle size, aggregation state, charge potential, and stability of secondary and tertiary structures of EYCMC. The behavior of EYCMC at the oil-water interface was mainly divided into three phases: rapid diffusion, permeation, and reorganization. The electrostatic interaction, kinetic hindrance, and depletion attraction were the mechanisms primarily involved in stabilizing HIPPEs by EYCMC. Rheological analysis results indicated that HIPPEs had excellent viscoelasticity, structural recovery properties and yield stress. HIPPEs were used in 3D printing, electronic nose testing, IDDSI testing and in vitro digestive simulations for the elderly, demonstrating a fine appearance, safe consumption and bioaccessibility of β-carotene. Soluble complexes showed the best stability and age friendliness compared to other aggregated forms. This study serves as a foundational source of information for developing innovative foods utilizing HIPPEs.

Effects of freezing on the gelation behaviors of liquid egg yolks affected by saccharides: thermal behaviors and rheological and structural changes

Monitoring and controlling the freezing process and thermal properties of foods is an important means to understand and maintain product quality. Saccharides were used in this study to regulate the gelation of liquid egg yolks induced by freeze‒thawing; the selected saccharides included sucrose, L-arabinose, xylitol, trehalose, D-cellobiose, and xylooligosaccharides. The regulatory effects of saccharides on frozen egg yolks were investigated by characterizing their thermal and rheological properties and structural changes. The results showed that L-arabinose and xylitol were effective gelation regulators. After freeze‒thawing, the sugared egg yolks exhibited a lower consistency index and fewer rheological units than those without saccharides, indicating controlled gelation. Weaker aggregation of egg yolk proteins was confirmed by smaller aggregates observed by confocal laser scanning microscopy and smaller particle sizes. Saccharides alleviated the freeze-induced conversion of α-helices to β-sheets in egg yolk proteins, exposing fewer Trp residues. Overall, L-arabinose showed the greatest improvement in regulating the gelation of egg yolks, followed by xylitol, which is correlated with its low molecular weight.

Integrated extraction, structural characterization, and activity assessment of squid pen protein hydrolysates and β-chitin with different protease hydrolysis

Squid pen (SP) is a valuable source of protein and β-chitin. However, current research has primarily focused on extracting β-chitin from SP. This study innovatively extracted both SP protein hydrolysates (SPPHs) and SP β-chitin (SPC) simultaneously using protease hydrolysis. The effects of different proteases on their structural characteristics and bioactivity were evaluated. The results showed that SP alcalase β-chitin (SPAC) had the highest degree of deproteinization (DP, 98.19 %) and SP alcalase hydrolysates (SPAH) had a degree of hydrolysis (DH) of 24.47 %. The analysis of amino acid composition suggested that aromatic amino acids accounted for 17.44 % in SPAH. Structural characterization revealed that SP flavourzyme hydrolysates (SPFH) had the sparsest structure. SPC exhibited an excellent crystallinity index (CI, over 60 %) and degree of acetylation (DA, over 70 %). During simulated gastrointestinal digestion (SGD), the hydroxyl radical scavenging activity, ABTS radical scavenging activity, Fe2+ chelating activity, and reducing power of the SPPHs remained stable or increased significantly. Additionally, SPFC exhibited substantial inhibitory effects on Staphylococcus aureus and Escherichia coli (S. aureus and E. coli), with inhibition circle diameters measuring 2.4 cm and 2.1 cm. These findings supported the potential use of SPPHs as natural antioxidant alternatives and suggested that SPC could serve as a potential antibacterial supplement.

Advancements in Mid-Infrared spectroscopy of extracellular vesicles

Extracellular vesicles (EVs) are lipid vesicles secreted by all cells into the extracellular space and act as nanosized biological messengers among cells. They carry a specific molecular cargo, composed of lipids, proteins, nucleic acids, and carbohydrates, which reflects the state of their parent cells. Due to their remarkable structural and compositional heterogeneity, characterizing EVs, particularly from a biochemical perspective, presents complex challenges. In this context, mid-infrared (IR) spectroscopy is emerging as a valuable tool, providing researchers with a comprehensive and label-free spectral fingerprint of EVs in terms of their specific molecular content. This review aims to provide an up-to-date critical overview of the major advancements in mid-IR spectroscopy of extracellular vesicles, encompassing both fundamental and applied research achievements. We also systematically emphasize the new possibilities offered by the integration of emerging cutting-edge IR technologies, such as tip-enhanced and surface-enhanced spectroscopy approaches, along with the growing use of machine learning for data analysis and spectral interpretation. Additionally, to assist researchers in navigating this intricate subject, our manuscript includes a wide and detailed collection of the spectral peaks that have been assigned to EV molecular constituents up to now in the literature.

Rapid and accurate screening of cystic echinococcosis in sheep based on serum Fourier-transform infrared spectroscopy combined with machine learning algorithms

Cystic echinococcosis (CE) in sheep is a serious zoonotic parasitic disease caused by Echinococcus granulosus sensu stricto (s.s.). Presently, the screening technology for CE in sheep is time-consuming and inaccurate, and novel screening technology is urgently needed. In this work, we combined machine-learning algorithms with Fourier transform infrared (FT-IR) spectroscopy of serum to establish a quick and accurate screening approach for CE in sheep. Serum samples from 77 E. granulosus s.s.-infected sheep to 121 healthy control sheep were measured by FT-IR spectrometer. To optimize the classification accuracy of the serum FI-TR method for the E. granulosus s.s.-infected sheep and healthy control sheep, principal component analysis (PCA), linear discriminant analysis, and support vector machine (SVM) algorithms were used to analyze the data. Among all the bands, 1500-1700 cm^-1 band has the best classification effect; its diagnostic sensitivity, specificity, and accuracy of PCA-SVM were 100%, 95.74%, and 96.66%, respectively. The study showed that serum FT-IR spectroscopy combined with machine learning algorithms has great potential for rapid and accurate screening methods for the CE in sheep.

Effects of Sequential Enzymolysis and Glycosylation on the Structural Properties and Antioxidant Activity of Soybean Protein Isolate

The effects of limited hydrolysis following glycosylation with dextran on the structural properties and antioxidant activity of the soybean protein isolate (SPI) were investigated. Three SPI hydrolysate (SPIH) fractions, F30 (>30 kDa), F30-10 (10-30 kDa), and F10 (<10 kDa), were confirmed using gel permeation chromatography. The results demonstrated that the glycosylation of F30 was faster than that of F30-10 or F10. The enzymolysis caused the unfolding of the SPI to expose the internal hydrophobic cores, which was further promoted by the grafting of dextran, making the obtained conjugates have a loose spatial structure, strong molecular flexibility, and enhanced thermal stability. The grafting of dextran significantly enhanced the DPPH radical or •OH scavenging activity and the ferrous reducing power of the SPI or SPIH fractions with different change profiles due to their different molecular structures. The limited enzymolysis following glycosylation was proven to be a promising way to obtain SPI-based food ingredients with enhanced functionalities.

Ultrasound-assisted pH-shifting remodels egg-yolk low-density lipoprotein to enable construction of a stable aqueous solution of vitamin D3

Egg-yolk low-density lipoprotein (LDL) has a natural liposome structure. Using ultrasound-assisted pH-shifting (pH 12), a naturally safe and stable aqueous solution of vitamin D₃ (VD₃) was constructed employing LDL as the carrier. Images from electron microscopy showed that pH-shifting remodeled LDL molecules, resulting in a dramatic reduction in particle size (∼50%) and an increase in specific surface area, which reduced the turbidity (27.7%) and provided new interfaces for VD₃ loading. Fluorescence analyses showed that the binding of VD₃ to LDL under pH-shifting was strong, involved quenching, and the binding constant was 6.19 × 10⁴ M⁻¹. Thermogravimetric analysis and Fourier transform-infrared spectroscopy showed that pH-shifting hydrolyzed the esters in LDL to fatty acid salts, and the maximum weight loss of LDL occurred from 381.9 °C to 457.0 °C. Ultrasonic treatment enhanced the binding of LDL and VD₃ (binding constant increased to 2.56 × 10⁷ M⁻¹), reduced the particle size, and increased the ζ-potential of the complex between LDL and VD₃, thereby resulting in the improvement of solution stability and storage stability of VD₃. Ultrasound-assisted pH-shifting could remodel LDL to construct a stable aqueous solution of VD₃, which showed the potential of LDL as a carrier for lipid-soluble components.

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pH-shifting remodels LDL and results in a reduction in particle size.

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Under pH-shifting, VD₃ was bound stably to LDL with strong affinity.

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pH-shifting remodeled LDL can be used to encapsulate active ingredients.

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The binding of VD₃ to LDL was enhanced by ultrasonic treatment.

Au3+-Induced gel network formation of proteins

The formation of protein gel networks in aqueous systems is a result of protein intermolecular interactions after an energy input, like heating. In this research, we report that a redox reaction between Au³⁺ ions and proteins can also lead to the formation of a protein gel network. Amino acids, like cysteine and tyrosine, get oxidized and form covalent bonds with neighboring protein molecules, while Au³⁺ ions get reduced to Au⁺ and Au⁰, nucleate and form gold nanoparticles. The protein gel network formation occurs within 2 h at room temperature and can be tuned by varying Au³⁺/protein ratio and accelerated by increasing the incubation temperature. The proposed Au³⁺-induced gel network formation was applied to different proteins, like egg yolk high-density lipoprotein, bovine serum albumin and whey protein. This research opens new insights for the investigation of the metal-protein interactions and may aid in the design of novel hybrid-soft nanocomposite materials.

On the nature of peculiar expectorated bronchial casts: Can infrared spectroscopy enlighten us?

BACKGROUND

Bronchial casts can be defined as gelatinous structures originating from the airways. While several cases of bronchial cast formation have been reported in literature, unravelling its nature is often a difficult task.

METHODS

In this case report, we applied infrared (IR) spectroscopy on a bronchial cast fragment originating from a patient who suffered from a 2-y history of frequent coughing accompanied by the occasional expectoration of viscous and thick white-yellow bronchial-like structures.

RESULTS

Based on a markedly high lipid to protein ratio and presence of long-chain fatty acids, the resulting IR spectrum appeared to be very suggestive for chyloptysis.

CONCLUSION

Taking into account the patient's prior history of radiation therapy for a lymphoma complicated by congestive heart failure, we hypothesized that an impairment of adequate lymphatic flow into the venous system due to a combination of lymphatic obstruction and high venous pressures is the most plausible culprit.

PLS-DA Model for the Evaluation of Attention Deficit and Hyperactivity Disorder in Children and Adolescents through Blood Serum FTIR Spectra

Attention deficit and hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders of childhood. It affects ~10% of the world's population of children, and about 30-50% of those diagnosed in childhood continue to show ADHD symptoms later, with 2-5% of adults having the condition. Current diagnosis of ADHD is based on the clinical evaluation of the patient, and on interviews performed by clinicians with parents and teachers of the children, which, together with the fact that it shares common symptoms and frequent comorbidities with other neurodevelopmental disorders, makes the accurate and timely diagnosis of the disorder a difficult task. Despite the large effort to identify reliable biomarkers that can be used in a clinical environment to support clinical diagnosis, this goal has never been achieved hitherto. In the present study, infrared spectroscopy was used together with multivariate statistical methods (hierarchical clustering and partial least-squares discriminant analysis) to develop a model based on the spectra of blood serum samples that is able to distinguish ADHD patients from healthy individuals. The developed model used an approach where the whole infrared spectrum (in the 3700-900 cm^-1 range) was taken as a holistic imprint of the biochemical blood serum environment (spectroscopic biomarker), overcoming the need for the search of any particular chemical substance associated with the disorder (molecular biomarker). The developed model is based on a sensitive and reliable technique, which is cheap and fast, thus appearing promising to use as a complementary diagnostic tool in the clinical environment.

Tunneling Atomic Force Microscopy Analysis of Supramolecular Self-Responsive Nanocomposites

A big step forward for composite application in the sector of structural materials is given by the use of Multi-Wall Carbon Nanotubes (MWCNTs) functionalized with hydrogen bonding moieties, such as barbiturate and thymine, to activate self-healing mechanisms and integrate additional functionalities. These materials with multiple healing properties at the same damaged site, imparted by hydrogen bonds, will also have the potential to improve material reliability, extend the service life, reduce replacement costs, and improve product safety. This revolutionary approach is obtained by integrating the non-covalent interactions coupled with the conventional covalent approach used to cross-link the polymer. The objective of this work is to characterize rubber-toughened supramolecular self-healing epoxy formulations based on unfunctionalized and functionalized MWCNTs using Tunneling Atomic Force Microscopy (TUNA). This advanced technique clearly shows the effect produced by the hydrogen bonding moieties acting as reversible healing elements by their simultaneous donor and acceptor character, and covalently linked to MWCNTs to originate self-healing nanocomposites. In particular, TUNA proved to be very effective for the morphology study of both the unfunctionalized and functionalized carbon nanotube-based conductive networks, thus providing useful insights aimed at understanding the influence of the intrinsic nature of the nanocharge on the final properties of the multifunctional composites.

Iron-Stimulated Production and Antimicrobial Potential of a Novel Biosurfactant Produced by a Drilling Waste-Degrading Pseudomonas citronellolis Strain

A Pseudomonas citronellolis strain was isolated from drilling waste (DW). This strain utilizes DW as the sole energy and carbon source to produce biosurfactants (BSs). The BS produced was thermally stable, amorphous and includes a peptide structure. FeSO4, FeCl3 and Fe(NO3)3 were supplemented at various concentration levels to assess possible enhancement of BS production and DW biodegradation. The limit concentration of Fe compounds between the increase in BS formation and microbial toxicity was 0.1 mM. FeCl3 enhanced DW biodegradation and more than doubled the BS formation yield, determining an optimization strategy for BS production. The BS was then partially purified and used against several Gram-negative and positive multi-drug resistant bacteria (such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli spp, Acinetobacter baumaniii, Enterococcus faecalis spp, Streptococcus pneumoniae, Staphylococcus aureus, Salmonella enterica). The minimum inhibitory concentration was defined at a range of 0.25 to 10 mg/mL. The antimicrobial properties of the partially purified BS established its effectiveness and suggested a down-stream processing cost reduction, as no additional purification steps were necessary. The study could lead to a sustainable low-cost bioprocess towards a circular bioeconomy because waste, a non-expensive substrate, is used; while the BS holds great potential as a novel compound with antibiotic and disinfectant-like action, following toxicity testing with human cells.

Fourier Transform Infrared Spectroscopy Based Complementary Diagnosis Tool for Autism Spectrum Disorder in Children and Adolescents

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that begins early in life and continues lifelong with strong personal and societal implications. It affects about 1%-2% of the children population in the world. The absence of auxiliary methods that can complement the clinical evaluation of ASD increases the probability of false identification of the disorder, especially in the case of very young children. In this study, analytical models for auxiliary diagnosis of ASD in children and adolescents, based on the analysis of patients' blood serum ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared) spectra, were developed. The models use chemometrics (either Principal Component Analysis (PCA) or Partial Least Squares Discriminant Analysis (PLS-DA)) methods, with the infrared spectra being the X-predictor variables. The two developed models exhibit excellent classification performance for samples of ASD individuals vs. healthy controls. Interestingly, the simplest, unsupervised PCA-based model results to have a global performance identical to the more demanding, supervised (PLS-DA)-based model. The developed PCA-based model thus appears as the more economical alternative one for use in the clinical environment. Hierarchical clustering analysis performed on the full set of samples was also successful in discriminating the two groups.

Effects of high-intensity ultrasonic (HIU) treatment on the functional properties and assemblage structure of egg yolk

The effects of high-intensity ultrasonic (HIU) treatment on the functional properties of egg yolk were studied in the present work. After HIU treatment, the emulsifying, foaming and gel properties of the egg yolk solution significantly increased, but the foam stability decreased. SDS-PAGE results showed that there was no obvious change in the protein bands of egg yolk, indicating that the yolk proteins did not undergo covalent crosslinking or degradation. HIU treatment enhanced the zeta potential of egg yolk components in solution and increased the free sulfhydryl content of egg yolk proteins. Moreover, the particle size distribution of egg yolk components in solution changed markedly, and these changes demonstrated that HIU treatment caused the aggregation of yolk low-density lipoprotein and the partial dissociation of yolk granules. These results revealed that HIU treatment could change the aggregation of yolk components, which in turn could influence the solution characteristics of egg yolk, finally resulting in changes to the functional properties of egg yolk.

Estimating the Level of Carbamoylated Plasma Non-High-Density Lipoproteins Using Infrared Spectroscopy

BACKGROUND

The increased cardiovascular morbidity and mortality observed in chronic kidney disease (CKD) patients can be partly explained by the presence of carbamoylated lipoproteins. Lipid profiles can be determined with infrared spectroscopy. In this paper, the effects of carbamoylation on spectral changes of non-high-density lipoproteins (non-HDL) were studied.

METHODS

In the present study, fasting serum samples were obtained from 84 CKD patients (CKD stage 3-5: n = 37 and CKD stage 5d (hemodialysis): n = 47) and from 45 healthy subjects. In vitro carbamoylation of serum lipoproteins from healthy subjects was performed using increasing concentrations of potassium cyanate. Lipoprotein-containing pellets were isolated by precipitation of non-HDL. The amount of carbamoylated serum non-HDL was estimated using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, followed by soft independent modelling by class analogy analysis.

RESULTS

Carbamoylation resulted in a small increase of the amide I band (1714-1589 cm^-1) of the infrared spectroscopy (IR) spectrum. A significant difference in the amide II/amide I area under the curves (AUC) ratio was observed between healthy subjects and CKD patients, as well as between the two CKD groups (non-dialysis versus hemodialysis patients).

CONCLUSIONS

ATR-FTIR spectroscopy can be considered as a novel method to detect non-HDL carbamoylation.

The Effects of Cordyceps sinensis (Berk.) Sacc. and Gymnema inodorum (Lour.) Decne. Extracts on Adipogenesis and Lipase Activity In Vitro

This study aimed to investigate the effects of Cordyceps sinensis extract (CSE) and Gymnema inodorum extract (GIE), used alone and combined, on antiadipogenesis in 3T3-L1 cells. Oil Red O staining was used to examine the effects of these extracts on inhibition of intracellular lipid accumulation in 3T3-L1 adipocytes and on lipid droplet morphology. Fourier transform-infrared (FTIR) microspectroscopy was used to examine biomolecular changes in 3T3-L1 adipocytes. The pancreatic lipase assay was used to evaluate the inhibitory effects of CSE and GIE on pancreatic lipase activity. Taken together, the results indicated that CSE, GIE, and their combination suppressed lipid accumulation. The FTIR microspectroscopy results indicated that CSE, GIE, and their combination had inhibitory effects on lipid accumulation in the adipocytes. Compared with the untreated adipocytes, the signal intensity and integrated areas of glycogen and other carbohydrates, the acyl chain of phospholipids, and the lipid/protein ratios of the CSE, GIE, alone, and combined treated adipocytes were significantly lower (p < 0.05). Combination treatment resulted in a synergistic effect on lipid accumulation reduction in the adipocytes. Principal component analysis of the biomolecular changes revealed six distinct clusters in the FTIR spectra of the sample cells. The pancreatic lipase assay results indicated that CSE and GIE inhibited the pancreatic lipase activity in a dose-dependent manner (mean ± standard error of the mean IC₅₀ values, 2312.44 ± 176.55 μg mL⁻¹ and 982.24 ± 44.40 μg mL⁻¹, resp.). Our findings indicated that FTIR microspectroscopy has potential application for evaluation of the effectiveness of medicinal plants and for the development of infrared biochemical obesity markers useful for treating patients with obesity. These results suggested that use of CSE and GIE alone and in combination may be efficacious as a complementary therapy for hyperlipidemia and obesity management. However, clinical trials in animals and humans must first be completed.

Effect of Native and Modified Apolipoprotein A-I on DNA Synthesis in Cultures of Different Cells

Culturing of bone marrow cells in serum-free RPMI-1640 medium for 24 h was accompanied by a decrease in the rate of [3H]-thymidine incorporation into DNA. Addition of native apolipoprotein A-I (apoA-I) or plasma LDL and HDL to the culture medium increased this parameter. In contrast to native apoA-I, its modified form decelerated DNA synthesis in bone marrow cells. A similar inhibitory effect of modified protein was observed in cultures of human embryonic kidney cells (HEK293) and in rapidly proliferating mouse macrophage cell line ANA-1. The only exclusion was human myeloid cell line U937: neither native nor modified apoA-I affected DNA synthesis in these cells. Thus, the regulatory effects of apoA-I are tissue-specific; this protein can produce either stimulatory or inhibitory effect on DNA biosynthesis in cells depending on its conformation.

Oxidative stress in ageing and disease development studied by FT-IR spectroscopy

FT-IR spectroscopy was used to investigate the effect of oxidative stress and to approach the mechanism on cancer bone demineralization, aortic valve mineralization and heterotopic ossification on disease development. The FT-IR spectra obtained from paediatric, adult bone and ex vivo irradiated adult healthy bone with a dose of 20Gy were compared with those of healthy bone. The increase of band intensity changes of vasCH_2,vsCH₂ in the region 3000-2850cm^-1 depended on aging, the disease progression and the dose of irradiation. The bands at 3080cm^-1 and 1744cm^-1, which originate from olefinic terminal bond (v=CH) and ester carbonyl group (vROCO), respectively, indicate the influence of oxidative stress on lipid degradation and peroxidation, respectively. The new bands at about 1690cm^-1 and 1516cm^-1 denote the presence of β-sheet conformation of the proteins due to the diseases, confirming the increasing amount of lipophilic environment and fibril formation. Comparison of the FT-IR spectra of calcified aortic valve and hip heterotopic ossification with that of normal bones showed that in the bone-like formation the peroxide anion free radicals play an important role in the disease.

Comparison of FTIR-ATR and Raman spectroscopy in determination of VLDL triglycerides in blood serum with PLS regression

Hypertriglyceridemia, related with triglyceride (TG) in plasma above 1.7mmol/L is one of the cardiovascular risk factors. Very low density lipoproteins (VLDL) are the main TG carriers. Despite being time consuming, demanding well-qualified staff and expensive instrumentation, ultracentrifugation technique still remains the gold standard for the VLDL isolation. Therefore faster and simpler method of VLDL-TG determination is needed. Vibrational spectroscopy, including FT-IR and Raman, is widely used technique in lipid and protein research. The aim of this study was assessment of Raman and FT-IR spectroscopy in determination of VLDL-TG directly in serum with the isolation step omitted. TG concentration in serum and in ultracentrifugated VLDL fractions from 32 patients were measured with reference colorimetric method. FT-IR and Raman spectra of VLDL and serum samples were acquired. Partial least square (PLS) regression was used for calibration and leave-one-out cross validation. Our results confirmed possibility of reagent-free determination of VLDL-TG directly in serum with both Raman and FT-IR spectroscopy. Quantitative VLDL testing by FT-IR and/or Raman spectroscopy applied directly to maternal serum seems to be promising screening test to identify women with increased risk of adverse pregnancy outcomes and patient friendly method of choice based on ease of performance, accuracy and efficiency.

Infrared analysis of lipoproteins in the detection of alcohol biomarkers

Background:

Alcoholism is a major public health problem. Alcohol causes modifications in the composition and concentration of lipoproteins and influences the enzymes and transfer proteins that transform lipoproteins in plasma. Alcohol is associated with the presence of alcohol biomarkers (fatty acid ethyl esters [FAEEs] and phosphatidylethanol [PEth]) in lipoproteins. We explore the possibilities of detecting alcohol biomarkers in non-high-density-lipoproteins (non-HDLs) precipitated from serum using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR).

Methods:

Analyzes were carried out on stored serum samples, with known % carbohydrate-deficient transferrin (CDT) values, included in a driver’s license regranting program under the control of the Belgian Institute of Road Safety. The study consisted of 127 control samples (CDT≤1.3%) and 114 alcoholic samples (CDT>1.3%). Liver enzymes, CRP, triglycerides, total, HDL- and LDL-cholesterol values were determined. Non-HDLs were precipitated with sodium phosphotungstate and MgCl2 and analyzed using ATR-FTIR in the range from 4500 cm−1 to 450 cm−1 using a Perkin Elmer ATR-FTIR Spectrometer Two.

Results:

The area under the curve of the 1130–990 cm−1 region (AUC1130−990 cm−1) was able to discriminate controls from alcoholics (p<0.0001) due to the presence of FAEEs in lipoproteins. Multiple regression analysis significantly predicted the AUC1130−990 cm−1 (adj. r2=0.13, p<0.0001). Significant correlations were found between AUC1130−990 cm−1 and CDT values (r=0.32, p<0.0001), AST/ALT ratio (r=0.21, p=0.001). GGT showed no significant correlation.

Conclusions:

Infrared analysis of lipoproteins is a potential tool in the detection of alcohol biomarkers.

Infrared spectroscopic characterization of monocytic microvesicles (microparticles) released upon lipopolysaccharide stimulation

Microvesicles (MVs) are involved in cell-cell interactions, including disease pathogenesis. Nondestructive Fourier-transform infrared (FTIR) spectra from MVs were assessed as a technique to provide new biochemical insights into a LPS-induced monocyte model of septic shock. FTIR spectroscopy provided a quick method to investigate relative differences in biomolecular content of different MV populations that was complementary to traditional semiquantitative omics approaches, with which it is difficult to provide information on relative changes between classes (proteins, lipids, nucleic acids, carbohydrates) or protein conformations. Time-dependent changes were detected in biomolecular contents of MVs and in the monocytes from which they were released. Differences in phosphatidylcholine and phosphatidylserine contents were observed in MVs released under stimulation, and higher relative concentrations of RNA and α-helical structured proteins were present in stimulated MVs compared with MVs from resting cells. FTIR spectra of stimulated monocytes displayed changes that were consistent with those observed in the corresponding MVs they released. LPS-stimulated monocytes had reduced concentrations of nucleic acids, α-helical structured proteins, and phosphatidylcholine compared with resting monocytes but had an increase in total lipids. FTIR spectra of MV biomolecular content will be important in shedding new light on the mechanisms of MVs and the different roles they play in physiology and disease pathogenesis.-Lee, J., Wen, B., Carter, E. A., Combes, V., Grau, G. E. R., Lay, P. A. Infrared spectroscopic characterization of monocytic microvesicles (microparticles) released upon lipopolysaccharide stimulation.

An interdisciplinary computational/experimental approach to evaluate drug-loaded gold nanoparticle tumor cytotoxicity

AIM

Clinical translation of cancer nanotherapy has largely failed due to the infeasibility of optimizing the complex interaction of nano/drug/tumor/patient parameters. We develop an interdisciplinary approach modeling diffusive transport of drug-loaded gold nanoparticles in heterogeneously-vascularized tumors.

MATERIALS & METHODS

Evaluated lung cancer cytotoxicity to paclitaxel/cisplatin using novel two-layer (hexadecanethiol/phosphatidylcholine) and three-layer (with high-density-lipoprotein) nanoparticles. Computer simulations calibrated to in-vitro data simulated nanotherapy of heterogeneously-vascularized tumors.

RESULTS

Evaluation of free-drug cytotoxicity between monolayer/spheroid cultures demonstrates a substantial differential, with increased resistance conferred by diffusive transport. Nanoparticles had significantly higher efficacy than free-drug. Simulations of nanotherapy demonstrate 9.5% (cisplatin) and 41.3% (paclitaxel) tumor radius decrease.

CONCLUSION

Interdisciplinary approach evaluating gold nanoparticle cytotoxicity and diffusive transport may provide insight into cancer nanotherapy.

FT-IR spectroscopy and multivariate analysis as an auxiliary tool for diagnosis of mental disorders: Bipolar and schizophrenia cases

In this study, a methodology based on Fourier-transform infrared spectroscopy and principal component analysis and partial least square methods is proposed for the analysis of blood plasma samples in order to identify spectral changes correlated with some biomarkers associated with schizophrenia and bipolarity. Our main goal was to use the spectral information for the calibration of statistical models to discriminate and classify blood plasma samples belonging to bipolar and schizophrenic patients. IR spectra of 30 samples of blood plasma obtained from each, bipolar and schizophrenic patients and healthy control group were collected. The results obtained from principal component analysis (PCA) show a clear discrimination between the bipolar (BP), schizophrenic (SZ) and control group' (CG) blood samples that also give possibility to identify three main regions that show the major differences correlated with both mental disorders (biomarkers). Furthermore, a model for the classification of the blood samples was calibrated using partial least square discriminant analysis (PLS-DA), allowing the correct classification of BP, SZ and CG samples. The results obtained applying this methodology suggest that it can be used as a complimentary diagnostic tool for the detection and discrimination of these mental diseases.

Biomedical investigations using Fourier transform-infrared microspectroscopy

One of the most exciting recent developments in infrared spectroscopy has been the coupling of the spectrometer to an infrared microscope. The combination of the new infrared spectrometer and a microscope was a natural thought of scientists in these fields. This development has been so rewarding and so useful in solving today's chemical problems that infrared microspectroscopy has quickly become a significant subclassification of infrared spectroscopy. Infrared microspectroscopy has a much longer history than the recent enthusiasm would imply, however. The great interest in the use of infrared spectroscopy to solve biomedical problems that occurred in recent years shortly spread into the medical and biological fields. The aim of this review is to discuss the new developments in applications of FT-IR microspectroscopy in biomedical analysis, covering the period between 2008 and 2013.

Release kinetics of paclitaxel and cisplatin from two and three layered gold nanoparticles

Gold nanoparticles functionalized with biologically compatible layers may achieve stable drug release while avoiding adverse effects in cancer treatment. We study cisplatin and paclitaxel release from gold cores functionalized with hexadecanethiol (TL) and phosphatidylcholine (PC) to form two-layer nanoparticles, or TL, PC, and high density lipoprotein (HDL) to form three-layer nanoparticles. Drug release was monitored for 14 days to assess long term effects of the core surface modifications on release kinetics. Release profiles were fitted to previously developed kinetic models to differentiate possible release mechanisms. The hydrophilic drug (cisplatin) showed an initial (5-h) burst, followed by a steady release over 14 days. The hydrophobic drug (paclitaxel) showed a steady release over the same time period. Two layer nanoparticles released 64.0±2.5% of cisplatin and 22.3±1.5% of paclitaxel, while three layer nanoparticles released the entire encapsulated drug. The Korsmeyer-Peppas model best described each release scenario, while the simplified Higuchi model also adequately described paclitaxel release from the two layer formulation. We conclude that functionalization of gold nanoparticles with a combination of TL and PC may help to modulate both hydrophilic and hydrophobic drug release kinetics, while the addition of HDL may enhance long term release of hydrophobic drug.

Cardiomyocyte intracellular cholesteryl ester accumulation promotes tropoelastin physical alteration and degradation: Role of LRP1 and cathepsin S

Dyslipemia has a direct impact on cardiac remodeling by altering extracellular matrix (ECM) components. One of the main ECM components is elastin, a proteic three-dimensional network that can be efficiently degraded by cysteine proteases or cathepsins. Dyslipemic status in insulin resistance and combined hyperlipoproteinemia diseases include raised levels of very low density lipoproteins (VLDL), triglyceride (TG)-cholesteryl ester (CE)-rich lipoproteins. Enhanced VLDL concentration promotes cardiomyocyte intracellular cholesteryl ester (CE) accumulation in a LRP1-dependent manner. The aim of this work was to analyze the effect of cardiomyocyte intracellular CE accumulation on tropoelastin (TE) characteristics and to investigate the role of LRP1 and cathepsin S (CatS) on these effects. Molecular studies showed that LRP1 deficiency impaired CE selective uptake and accumulation from TG-CE-rich lipoproteins (VLDL+IDL) and CE-rich lipoproteins (aggregated LDL, agLDL). Biochemical and confocal microscopic studies showed that LRP1-mediated intracellular CE accumulation increased CatS mature protein levels and induced an altered intracellular TE globule structure. Biophysical studies evidenced that LRP1-mediated intracellular CE accumulation caused a significant drop of Tg2 glass transition temperature of cardiomyocyte secreted TE. Moreover, CatS deficiency prevented the alterations in TE intracellular globule structure and on TE glass transition temperature. These results demonstrate that LRP1-mediated cardiomyocyte intracellular CE accumulation alters the structural and physical characteristics of secreted TE through an increase in CatS mature protein levels. Therefore, the modulation of LRP1-mediated intracellular CE accumulation in cardiomyocytes could impact pathological ventricular remodeling associated with insulin-resistance and combined hyperlipoproteinemia, pathologies characterized by enhanced concentrations of TG-CE-rich lipoproteins.

Spectroscopic studies of alpha tocopherol interaction with a model liposome and its influence on oxidation dynamics

The influence of α-tocopherol on the surface conformation of liposome, as a model component of lipoproteins, and its role in oxidation process were studied. FT-IR spectra from suspensions of neat liposome, mixtures of liposome and α-tocopherol and liposome with incorporated α-tocopherol were analyzed. When α-tocopherol was incorporated into liposome, intensities of some bands were decreased or increased in comparison with the spectra of liposome and α-tocopherol mixture. These changes reflect the different localization of α-tocopherol in two types of liposome suspensions. The oxidation of liposome suspensions was initiated by addition of cupric ions. After prolonged oxidation, the differences in FT-IR spectra of oxidized samples were recorded. Differences were observed in comparison with spectra of native and oxidized liposomes were analyzed. The rate of oxidation was measured by EPR oximetry. Oxidation was generally very slow, but faster in liposome without α-tocopherol, indicating the protective role of α-tocopherol against liposome oxidation. On the other hand, liposome suspensions with EDTA in the buffer were not oxidized at all, while those with α-tocopherol and liposome mixture were only slightly oxidized. In this case the consumption of oxygen was the result of liposome oxidation supported by α-tocopherol. These results reflect the ambivalent role of α-tocopherol in liposome oxidation, similarly to findings in studies of lipoprotein oxidation.

Human LDL structural diversity studied by IR spectroscopy

Lipoproteins are responsible for cholesterol traffic in humans. Low density lipoprotein (LDL) delivers cholesterol from liver to peripheral tissues. A misleading delivery can lead to the formation of atherosclerotic plaques. LDL has a single protein, apoB-100, that binds to a specific receptor. It is known that the failure associated with a deficient protein-receptor binding leads to plaque formation. ApoB-100 is a large single lipid-associated polypeptide difficulting the study of its structure. IR spectroscopy is a technique suitable to follow the different conformational changes produced in apoB-100 because it is not affected by the size of the protein or the turbidity of the sample. We have analyzed LDL spectra of different individuals and shown that, even if there are not big structural changes, a different pattern in the intensity of the band located around 1617 cm⁻¹ related with strands embedded in the lipid monolayer, can be associated with a different conformational rearrangement that could affect to a protein interacting region with the receptor.

Enhanced penetration into 3D cell culture using two and three layered gold nanoparticles

Nano-scale particles sized 10–400 nm administered systemically preferentially extravasate from tumor vasculature due to the enhanced permeability and retention effect. Therapeutic success remains elusive, however, because of inhomogeneous particle distribution within tumor tissue. Insufficient tumor vascularization limits particle transport and also results in avascular hypoxic regions with non-proliferating cells, which can regenerate tissue after nanoparticle-delivered cytotoxicity or thermal ablation. Nanoparticle surface modifications provide for increasing tumor targeting and uptake while decreasing immunogenicity and toxicity. Herein, we created novel two layer gold-nanoshell particles coated with alkanethiol and phosphatidylcholine, and three layer nanoshells additionally coated with high-density-lipoprotein. We hypothesize that these particles have enhanced penetration into 3-dimensional cell cultures modeling avascular tissue when compared to standard poly(ethylene glycol) (PEG)-coated nanoshells. Particle uptake and distribution in liver, lung, and pancreatic tumor cell cultures were evaluated using silver-enhancement staining and hyperspectral imaging with dark field microscopy. Two layer nanoshells exhibited significantly higher uptake compared to PEGylated nanoshells. This multilayer formulation may help overcome transport barriers presented by tumor vasculature, and could be further investigated in vivo as a platform for targeted cancer therapies.