FTIR investigation of the secondary structure of type I collagen: New insight into the amide III band

Novel mechanisms for selenite biotransformation and selenium nanoparticles biogenesis in Acinetobacter sp. SX5 isolated from seleniferous soil

The high biotoxicity of selenium (Se) has spurred research into its microbial biotransformation into less toxic Se nanoparticles (SeNPs). However, the molecular mechanisms underlying microbially driven selenite transformation remain largely unknown. In the present study, Acinetobacter sp. SX5, a bacterial strain with high Se reduction capacity, was isolated from soil. The biotransformation of selenite by SX5 and the molecular mechanisms underlying the formation of SeNPs were investigated. SX5 almost completely transformed 5.0 mM selenite into intracellular and extracellular spherical SeNPs within 48 h. Fourier-transform infrared spectroscopy indicated that lipids, proteins, and carbohydrates were present on the surface of these SeNPs. Transcriptomic data subsequently revealed the significant upregulation of genes related to redox homeostasis and arsenate, pyruvate, and butanoate metabolism pathways. Gene mutation/complementation analysis confirmed that arsenate reductase (arsC) and NAD(P)-dependent alcohol dehydrogenase (dhaT1) facilitated selenite reduction in vivo. In vitro assays found that arsC and dhaT1 catalyzed Se(IV) reduction with NADPH acting as co-factor. To the best of our knowledge, this study is the first to present evidence for the participation of arsC and dhaT1 in selenite reduction in vivo, providing important insights into the molecular mechanisms underlying the biotransformation of Se(IV) and the biogenesis of SeNPs using Se-reducing bacteria.

In situ synthesis of silver nanoparticles on silk: producing antibacterial fabrics

Herein, we explored an effective method for preparing silver nanoparticles (Ag NPs)-coated antibacterial silk fabrics. In particular, using amino acids and cellulose from silk as reducing agents and silver nitrate as a precursor, Ag NPs were synthesised in situ on the surface of silk without requiring additional reducing agents and catalysts. The surface morphology and chemical composition of the involved samples were characterised using techniques such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Notably, silk and silk precursors (silkworm cocoons, silk fibers and sericin) could be used for in situ Ag NPs synthesis. Furthermore, the antibacterial properties of the samples were evaluated against Escherichia coli-a Gram-negative bacterium-as a model, demonstrating an impressive antibacterial rate of up to 99.91%. In addition, we investigated the water absorption behaviour of the samples at 25 °C by assessing their moisture regain, water retention value and vertical wick height. The results indicated that the Ag NPs coating did not damage the water absorption performance of the involved silk. Finally, we compared the fabric performance before and after treatment using a universal testing machine and colorimeter. The results showed that the mechanical properties of the fabrics with the Ag NPs coating did not substantially change with treatment, but the fabrics became more yellowish. Overall, this research has notable application potential in the field of antibacterial fabrics.

Portable Fourier-transform infrared spectroscopy and machine learning for sex determination in third instar Chrysomya rufifacies larvae

Forensic entomology is crucial in medicolegal investigations, utilizing insects-primarily flies-to estimate a supplemental post-mortem interval based on their development at the (death) scene. This estimation can be influenced by extrinsic factors like temperature and humidity, as well as intrinsic factors such as species and sex. Previously, benchtop Fourier-transform infrared (FTIR) spectroscopy coupled with machine learning demonstrated high accuracy in distinguishing the sex of third instar Cochliomyia macellaria larvae. This study leverages benchtop- and handheld-based FTIR spectroscopy combined with machine learning models-Partial Least Squares Discriminant Analysis (PLSDA), eXtreme Gradient Boosting trees Discriminant Analysis (XGBDA), and Artificial Neural Networks Discriminant Analysis (ANNDA)-to differentiate between male and female Chrysomya rufifacies larvae, commonly found on human remains. Significant vibrational differences were detected in the mid-infrared spectra of third instar Ch. rufifacies larvae, with a majority of peaks showing a higher abundance of proteins, lipids, and hydrocarbons in male larvae. PLSDA and ANNDA models developed using benchtop FTIR data achieved high external validation accuracies of approximately 90% and 94.5%, respectively, when tested with handheld FTIR data. This nondestructive approach offers the potential to refine supplemental post-mortem interval estimations significantly, enhancing the accuracy of forensic analyses of entomological evidence.

Fabrication and characterization of antioxidant fish oil Pickering emulsions stabilized by selenium nanoparticles-loaded whey protein concentrate and phloretin complex

This study aimed to enhance the nutritional value and oxidative stability of fortified milk by investigating the properties of fish oil Pickering emulsion (FOPE) stabilized by selenium nanoparticles (SeNP) loaded-whey protein concentrate/phloretin (WPC/PHL) complex. Initially, the influence of SeNP concentration on the WPC/PHL complex was evaluated through measurements of particle size, antioxidant activity, and intermolecular interactions. Results demonstrated that increasing SeNP concentration from 0.1 % to 0.3 % significantly enhanced the antioxidant activity, with ABTS assay values rising from 42.87 % to 76.14 % and DPPH assay values increasing from 59.10 % to 86.11 %. FTIR and docking analyses confirmed the formation of bonds (hydrogen and van der Waals) between the WPC/PHL/SeNP nanoparticles. Subsequently, the FOPEs were characterized, revealing that increasing SeNP concentration reduced droplet size, indicating improved emulsion stability. Furthermore, the oxidative stability of the emulsions improved with increasing SeNP concentrations (0.1 % to 0.3 %), as evidenced by a decrease in peroxide value (PV) from 4.27 meq/kgO2 to 2.83 meq/kgO2 and a reduction in malondialdehyde (MDA) content from 86.61 mg/kg oil to 62.78 mg/kg oil after 10 days of storage. Finally, the oxidative stability of fortified milk containing these FOPEs was also significantly enhanced. These findings provide a novel perspective on developing SeNP as an antioxidant particle, potentially suitable for formulating functional emulsified food products susceptible to oxidative deterioration.

Topography-guided, patterned, customized corneal crosslinking for non-invasive astigmatism correction

OBJECTIVES

To propose and evaluate a novel, non-invasive approach for enduring corneal astigmatism correction based on topography-guided, patterned, customized riboflavin-ultraviolet A corneal collagen crosslinking (CXL).

METHODS

Astigmatism was modelled on both eyes of rabbits. A randomly selected eye of each rabbit was treated by the proposed CXL procedure with another eye as control. The proposed procedure was performed by a self-built intelligent platform through delivering ultraviolet A lattice in a refined and patterned manner, based on pre-operative corneal topography. The long-term effectiveness, stability, and safety were investigated for 180 days, with topographic measurements, anterior segment optical coherence tomography (AS-OCT), and in vivo corneal confocal microscopy (IVCM).

RESULTS

Spatially selective demarcation lines in AS-OCT images and trabecular patterned hyperdense structure with abundant needle-like processes in IVCM images were detected in the CXL eyes, revealing spatially selective crosslinking. Reductions of astigmatic magnitude (in the steep axis: 0.46 ± 0.28 vs. 2.15 ± 0.58 dioptres, P < 0.001) and high order aberration (0.38 ± 0.18 vs. 0.59 ± 0.19, P = 0.009) with increase of visual strehl ratio (0.21 ± 0.06 vs. 0.13 ± 0.03, P < 0.001) were found in the CXL eyes after CXL and maintained for 180 days, compared to inconspicuous changes in the control eyes. No obvious opacity and inflammation were observed in the CXL eyes, and transient loss of endothelial cells in the treated area was recovered in the subsequent visit.

CONCLUSIONS

The proposed novel, non-invasive approach safely fulfilled corneal astigmatism correction with visual quality improvement as well as a decrease in high-order aberration.

Comparative characterization of leather from different tanning processes as a contribution for a sustainable development of the leather industry

Leather is a fully biobased material (100% biodegradable organic material, with collagen as the main constituent), derived from food industry byproducts (animal skin from butchery), which represents an excellence for the Italian industry (in the last years the production value reached 4.6 billion euros and an export of 3.2 billion euros) and a highly sustainable material. However, its production is still strongly handicraft, traditional and unfortunately based on the employment of toxic chemicals, such as chromium and glutaraldehyde. A deep knowledge of the tanning process and of the specific features of leather coming from different processing routes is crucial for the design and development of innovation in the field for a more sustainable and knowledge-based production. In this contest, the impact of tanning process on the surface reactivity of leather plays a crucial role. In the present research well established characterizations (optical microscopy, shrinkage temperature, wettability, metal content, infrared spectroscopy and X-ray diffraction) and new and unconventional methods for the leather field (surface topography, instrumented indentation and zeta potential electrokinetic measurements) were applied and optimized for the characterization of leather samples from traditional (e.g. Chrome and Glutaraldehyde) and innovative (e.g. vegetable, carbamoyl sulphate, starch, aluminum, zeolite, triazine and Olive Mill Wastewaters -OMW) tanning processes. The suitability of the characterization protocol for the in-depth investigation and comparison of leather samples from different processing has been demonstrated highlighting its applicability for a knowledge-based innovation in the leather field.

Antimicrobial peptide-fucoidan nanoplexes: A novel multifunctional biomimetic nanocarrier for enhanced vancomycin delivery against bacterial infections and sepsis

Sepsis, a critical medical emergency, continues to pose a substantial worldwide healthcare challenge that necessitates innovative approaches for enhanced treatment. Hence, this study aimed to develop multifunctional biomimetic vancomycin (VCM)-loaded nanoplexes (VCM-FU-PEP-NPs) utilizing a novel antimicrobial peptide (CC-19 peptide) and Fucoidan (FU) to target the Toll-like receptor (TLR) inflammatory pathway and augment the antibacterial efficacy against bacterial sepsis. The CC-19 peptide (CRPRKWIKIKFRCKSLKFC) was designed utilizing computer-aided drug design tools and subsequently synthesized. The biomimetic properties of FU were assessed through in silico and in vitro binding studies, demonstrating a strong affinity for TLR2. The formulated VCM-FU-PEP-NPs demonstrated appropriate physicochemical characteristics, physical stability, and biocompatibility. Moreover, VCM-FU-PEP-NPs exhibited a 2-fold increase in antibacterial efficacy against sensitive Staphylococcus aureus, superior and sustained antibacterial activity against MRSA over 72 h, 5-fold improvement in MRSA biofilm eradication, faster bacterial-killing kinetics, and significantly greater disruption of MRSA membranes, in comparison to bare VCM. Furthermore, VCM-FU-PEP-NPs exhibited excellent DPPH radical scavenging capacity and significant anti-inflammatory efficacy in cells exposed to bacterial toxins. Accordingly, VCM-FU-PEP-NPs demonstrate promise as a potential innovative, multifunctional antibiotic nanocarrier for advancing the treatment of sepsis.

Cold plasma-induced structural and thermal enhancements in marshmallow root mucilage-gelatin aerogels

Aerogels are highly regarded for their low density and large surface area, attracting significant attention due to their diverse applications. This study explored nitrogen cold plasma's impact on the structure and thermal stability of mucilage-gelatin aerogels (MGA). Aerogels were prepared using marshmallow root mucilage and gelatin in a 1:1 ratio and gelatin-only as a blank under different pH conditions (5 and 7). Rheological and texture analyses identified pH 7 as optimal. Aerogels at pH 7 were then exposed to cold plasma for varying durations (0, 3, and 6 min). Thermogravimetric analysis (TGA), differential thermal analysis (DTA), and X-ray diffraction (XRD) showed enhanced thermal stability and structural changes with increased plasma exposure. Fourier-transform Infrared Spectroscopy (FTIR) revealed functional group changes, and contact angle measurements showed that 3 min of plasma treatment increased hydrophilicity (88.37-82.05°), while 6 min enhanced hydrophobicity in 1:1 MGA (93.27°). BET (Brunauer-Emmett-Teller) analyses of the MGA samples revealed changes in surface area (2.9-4.33 m2/g after 3 min of plasma) and BJH (Barrett-Joyner-Halenda) pore volume (0.004-0.02 cm3/g), with a complex trend over time. This study highlights nitrogen cold plasma's potential to enhance mucilage-based biopolymer aerogels, paving the way for advanced materials via optimized treatments.

Polyphenols Improve the Digestibility of Eel Myofibrillar Protein by Alleviating Oxidation Through Noncovalent Interaction

The interaction between proteins and polyphenols helps mitigate the decrease in protein digestibility caused by oxidation. This study aimed to examine the effects of structurally varied polyphenols─propyl gallate (PG), gallic acid (GA), protocatechuic acid (PCA), and rosemary extracts (RE)─on the degree of oxidation and digestibility of eel myofibrillar protein (MP) under oxidative stress, clarifying their binding modes and mechanisms of interaction. All four phenolic substances reduced the level of protein oxidation. Adding 100 μmol/g of RE decreased carbonyl content by 56.16%, enhanced ABTS free radical scavenging rate by 67.34%, and improved digestibility by 33.18%. Noncovalent interactions between polyphenols and MP primarily involved hydrogen bonding and hydrophobic interactions. These interactions preserved the protein's ordered secondary structure, with RE increasing protein solubility by 67.01% under oxidative conditions. These findings suggest that natural polyphenols are effective antioxidants for eel protein, enhancing its functional properties and protecting it against oxidative stress.

Microwave-assisted protein extraction from foxtail millet: Optimization, structural characterization, techno-functional properties, and bioactivity of peptides

This research investigates the impact of microwave power, processing time, and solid-to-solvent ratio on protein recovery from foxtail millet (Setaria italica), using an artificial neural network (ANN) and genetic algorithm (GA). The extracted protein and subsequent hydrolysates were also evaluated for their techno-functional, structural, and digestibility properties. The ANN model, trained with the Levenberg-Marquardt algorithm and optimized by a GA, identified optimal extraction conditions (960 W, 66.14 s, 0.1264 g/mL), achieving a protein recovery yield of 30.02 ± 0.97 %. Protein recovery increased 1.15-fold for raw microwave-treated protein and 1.52-fold for germinated microwave-treated protein. The functional properties, including foaming, emulsifying, and digestibility were improved. Germinated microwave-treated protein hydrolysates (GMPH) exhibited the highest soluble protein content (17.79 ± 0.33 mg/mL) and degree of hydrolysis (7.63 ± 0.25 %) at 2.5 % (v/w) enzyme concentration, while raw microwave-treated protein hydrolysates (RMPH) showed 16.59 ± 0.36 mg/mL and 5.57 ± 0.14 %, respectively. Partially purified peptides from GMPH and RMPH showed strong antioxidant and angiotensin-converting enzyme (ACE) inhibitory activities, with GMPH showing the highest bioactivity. These findings highlight the potential of germination and microwave-assisted processing to produce high-quality protein and bioactive peptides, supporting the development of protein-rich foods and nutraceuticals to address global protein demand.

Tripolyphosphate-chitosan-pea protein interactions confers long-term stability to 3D printed high internal phase Pickering emulsions

This research explores the interactions of tripolyphosphate-chitosan-pea protein (TPP-CS-PP) in improving the stability and storage of 3D printing food inks. Chitosan (CS) and pea protein (PP) were complexed at various concentrations with 80 % palm olein to produce high internal phase Pickering emulsions (HIPPEs) 3D printing food inks. The resulting CSPP HIPPEs exhibited shear-thinning behaviour and the flexibility to switch between solid and liquid states, ideal for 3D printing. CSPP1:150 achieved the best 3D printing resolution and shape fidelity due to electrostatic attraction of CS-PP and excess PP enhancing adhesion at the oil/water interface. After spraying tripolyphosphate (TPP), crosslinking with CS and phosphorylation of PP further improved HIPPE resistance to deformation and oiling off for 2 days post-printing. This is a significant improvement over the control. Thus, further investigation on the interaction of TPP with CS and PP is warranted to further improve the storage stability of 3D printed food inks.

The impact of heating-induced lactosylation on the digestibility of lactotransferrin

Lactosylation of lysines occurs during the heating of dairy products, yet how lactosylation impact the lysine release during digestion remains largely unknown. This study examines the effect of lactosylation on the digestibility of lactotransferrin using chemical analysis, proteomics, and peptidomics. Under the applied heating conditions, lactotransferrin primarily undergoes early-stage Maillard reactions, producing lactulose-lysine. Furosine content increases with heating time and temperature, with time being more influential. And 23 out of 54 lysines in lactotransferrin were lactosylated. Following in-vitro infant digestion, free lysine levels in samples heated at 130 °C for 30s decreased by 25 % compared to unheated ones, likely due to lactosylation hindering protease cleavage. Intriguingly, lactosylated lysine was absent in peptides ranging from 5 to 17 amino acids but remained in larger peptides. The formation of large lactosylated peptides from heating impeded free lysine release. Further investigation is needed to determine if the human body can utilize these lactosylated peptides.

Non-invasive identification of historical textiles and leather by means of external reflection FTIR spectroscopy

Identifying the fibres in historical textiles presents a complex challenge due to the wide variety of plant, animal and early synthetic materials that have been used. Traditionally, this identification process involves sampling followed by either microscopic examination or ATR-FTIR spectroscopy. However, there are instances when sampling is restricted due to the good condition or significant value of the object under analysis. Additionally, the presence of leather components alongside textiles can further complicate the identification. This paper proposes a novel non-invasive method for fibre identification based on External Reflection (ER) FTIR spectroscopy, which has been rarely applied to textiles or leather. The current research demonstrates that ER-FTIR spectrum is a viable tool for fibre identification on both recent and historical textiles. The non-invasiveness of the analytical approach enables a comprehensive investigation without compromising the number or position of samples. Respect to ATR-FTIR spectra, the ER-FTIR spectra frequently exhibit an amplification of certain diagnostic bands, facilitating the identification of the various fibres examined in this study (cotton, hemp, viscose, silk, wool, leather, polyamide, acrylic, polyester). The extended spectral range (7500-375 cm-1) which is provided by ER-FTIR spectrometry also contains extra bands in the near infrared region, which can provide key information for the discrimination due to the lack of distortion phenomena. The technique was applied to the characterisation of textile materials coming from a collection of 10 traditional Japanese samurai armours spanning from the 16th to the 20th century (Museo delle Culture, Lugano, Switzerland). For the first time, the results provided a comprehensive overview of the textiles utilized in Japanese armours across various historical periods. Overall, the appearance of materials in samurai armours reflects the evolution of armour-making techniques and the influence of socio-cultural factors throughout Japanese history. Synthetic and semi-synthetic materials were easily detected, revealing the occurrence of a past conservation treatment or the early adoption of modern man-made materials in the manufacturing of traditional armours. The approach outlined in this case study can be applied to textile collections of various kinds, offering a reliable mean to discern the yarn composition and detect non-original components. The method also appears as a valuable prescreening tool for designing a less intrusive yet more informative sampling strategy, should additional details about fibre type and dyeing be necessary.

The optimization of sample preparation on zebrafish larvae in vibrational spectroscopy imaging

The zebrafish (Danio rerio) larvae are widely used in biomedical, pharmaceutical, and ecotoxicological studies. Their transparency and translational potential make them particularly valuable for fluorescence imaging. In addition to fluorescence imaging, microspectroscopy, which combines vibrational spectroscopy: Raman or Fourier transform infrared (FT-IR) with microscopy, allows the collection of spatially resolved, label-free information. According to available literature, it was the first application of FT-IR imaging in zebrafish larvae. This study aims to compare different fixation methods for 10-day post-fertilization (dpf) zebrafish larvae using vibrational spectroscopy imaging. Paraformaldehyde (PFA), glutaraldehyde (GA), low temperature, and embedding in gelatin and agarose were investigated. Amides, lipids, and phosphates distribution were more informative in embedded samples but with challenging handling of the sample due to stiffness at -20 °C. FT-IR and Raman mapping revealed that frozen samples had better-preserved tissue structure than chemical fixation. PFA showed uniform amide distribution, while GA treatment exhibited tissue disruptions and denser protein networks in both. Handling of embedded samples is challenging for an operator, but provides more reliable results in developmental biology or disease modeling, compared to chemical treatment.

Bovine serum albumin under the influence of alkali metal halides

The hydration shell of a protein is so important and an integral part of it, that protein's structure, stability and functionality cannot be conceived in its absence. This layer has unique properties not found in bulk water. However, ions, always present in the protein environment, disturb the hydration shell depending on their nature and concentration. In this work, we study the effect of four alkali metal halides (LiCl, NaCl, KCl and CsCl) on a Bovine Serum Albumin (BSA) suspension. In order to investigate the influence of such ions on this protein, we use several experimental methods: dynamic light scattering, differential scanning calorimetry, thermogravimetry, Fourier transform infrared spectroscopy and image analysis. We found that Li+ and Na+ prevent protein aggregation. Moreover, the ion size affects the interaction with the secondary structure of the protein (Amide III band). Notably, for the smallest ion (Li+), the water-ion interaction dominates over the Amide A band signature, contrasting with the other ions. We also differentiate between bulk and hydration water through the evaporation of protein suspensions.

Improvement of properties and olfactory attributes of isolated protein from edible insects by roasting

The characteristics of proteins extracted from two kinds of edible insects (Gryllus Bimaculatus and Tenebrio Molitor, for G.B and T.M, respectively) were compared after roasting at 180 °C for 15 min and 200 °C for 10 min, respectively. The amino acid content decreased by roasting, and the degree of decrease varied depending on the type of edible insect and roasting temperature. Antioxidant activity increased by 5.2-11.3% following roasting, with no significant differences by roasting temperature. The results of Infrared (IR) spectrum and gas chromatography (GC) analysis revealed that compounds contributing to a strong waxy scent and sour taste decreased, whereas those associated with aroma and floral scent increased as a result of roasting. In conclusion, roasting led to an enhancement in the olfactory characteristics of proteins extracted from edible insects, and roasting at 180 °C for 20 min for G.B and 200 °C for 15 min for T.M could be considered optimal.

Preparation and characterization of the ground mixture of rebamipide commercial tablets and Hydroxypropyl Cellulose-SSL by ball-milling: Application to the dispersoid of mouthwash suspension

In the present study, to prepare dispersoids with high dispersion stability that can be used as mouthwash, ground mixtures of commercial rebamipide (RB) tablets and hydroxypropyl cellulose (HPC-SSL) samples were prepared by dry milling. The physicochemical properties of the ground mixture of HPC-SSL and the powder obtained from the preliminary ground RB tablets were then compared. The dispersoids' physicochemical properties, dispersion stability, retention, and diffusiveness to the mucosal surfaces were evaluated in vitro. By co-grinding with HPC-SSL, RB transformed into fine particles around 303.6 - 361.5 nm that tended to prevent particle agglomeration in solution over time. The sample microparticles formed with HPC-SSL also avoided agglomeration on the mucosal surface for 24 h, improving oral retention. Furthermore, the ground mixture of HPC-SSL and the powder obtained from the preliminary ground RB tablets dispersed and permeated the mucus gel layer on the mucosal surface (24.2 %) but not the mucosal cells, indicating that RB remained on the mucosal surface. These results suggest that ground mixtures of commercial rebamipide (RB) tablets and hydroxypropyl cellulose (HPC-SSL) samples can be applied as a powdered suspension preparation because they showed high dispersion stability and oral mucosal retention.

Relative Aromaticity/Aliphaticity Steered Pore Structure in Polyamide-Derived Ultramicroporous Carbons for Efficient C3H6/C3H8 Separation

Carbon molecular sieves (CMS) with a tunable pore structure hold significant promise for efficient C3H6/C3H8 separation. However, understanding the relationship between a precursor's carbon framework and the microstructure of carbonized products is still ambiguous and requires further investigation. Herein, a relative aliphaticity/aromaticity regulated strategy was proposed to tailor the carbon skeleton of the polyamide precursor, aiming to fine tune the CMS pore size between the kinetic diameter of C3H6 (4.68 Å) and C3H8 (5.11 Å). The relative aliphaticity/aromaticity of the precursor was rationally modulated by replacing aromatic rings in diamine monomers with aliphatic chains of different lengths. Results indicated that polyamide precursors with higher relative aliphaticity exhibited increased susceptibility to fragmentation during carbonization. Thus, a higher degree of carbon layer restructuring arising from the degradation of aliphatic chains promoted the formation of orderly graphitized structures with sub 5 Å ultramicropores. The ETDA-derived CMS pyrolyzed at 700 °C (ETDA700) exhibited outstanding sieving performance in separating C3H6 from C3H8, with C3H6 uptakes of up to 2.33 mmol/g, while propane adsorption capacity was negligible. This work may provide valuable insights for the design of sieving carbonaceous material by rationally tuning precursor properties for the efficient separation of gas mixtures with similar sizes.

External Cavity Quantum Cascade Laser Vibrational Circular Dichroism Spectroscopy for Fast and Sensitive Analysis of Proteins at Low Concentrations

Proteins are characterized by their complex levels of structures, which in turn define their function. Understanding and evaluating these structures is therefore crucial to illuminating biological processes. One of the possible analytical methods is vibrational circular dichroism (VCD), which expands the structural sensitivity of classical infrared (IR) absorbance spectroscopy by the chiral sensitivity of circular dichroism. While this technique is powerful, it is plagued by low signal intensities and long measurement times. Here we present an optical setup leveraging the high brilliance of a quantum cascade laser to measure proteins in D2O at a path length of 204 μm. It was compared to classical Fourier-transform infrared spectroscopy (FT-IR) in terms of noise levels and in its applicability to secondary structure elucidation of proteins. Protein concentrations as low as 2 mg/mL were accessible by the laser-based system at a measurement time of 1 h. Further increase of the time resolution was possible by adapting the emission to cover only the amide I' band. This allowed for the collection of spectral data at a measurement time of 5 min without a loss of performance. With this high time resolution, we are confident that dynamic processes of protein can now be monitored by VCD, increasing our understanding of these reactions.

Soy protein isolate ameliorate gel properties by regulating the non-covalent interaction between epigallocatechin-3-gallate and myofibrillar protein

This study primarily investigated the improvement of high-dose Epigallocatechin-3-Gallate (EGCG)-induced deterioration of MP gel by soy protein isolate (SPI) addition. The results showed that EGCG could interact with MP, SPI, and HSPI (heated), indicating the competitive ability of SPI/HSPI against EGCG with MP. EGCG was encapsulated by SPI/HSPI with high encapsulation efficiency and antioxidation, with antioxidant activities of 78.5% ∼ 79.2%. FTIR and molecular docking results revealed that MP, SPI, and HSPI interacted with EGCG through hydrogen bonding and hydrophobic interactions. SPI/HSPI competed with MP for EGCG, leading to the restoration of MHC and Actin bands, alleviating the aggregation caused by EGCG and oxidation. Additionally, SPI/HSPI-E significantly reduced the high cooking loss (23.71 and 26.65%) and gel strength (13.60 and 17.02%) induced by EGCG. Hence, SPI competed with MP for EGCG binding site to ameliorate MP gel properties, thereby alleviating the detrimental changes in MP caused by high-dose EGCG and oxidation.

Novel Injectable Collagen/Glycerol/Pullulan Gel Promotes Osteogenic Differentiation of Mesenchymal Stem Cells and the Repair of Rat Cranial Defects

Bone tissue engineering is a technique that simulates the bone tissue microenvironment by utilizing cells, tissue scaffolds, and growth factors. The collagen hydrogel is a three-dimensional network bionic material that has properties and structures comparable to those of the extracellular matrix (ECM), making it an ideal scaffold and drug delivery system for tissue engineering. The clinical applications of this material are restricted due to its low mechanical strength. In this investigation, a collagen-based gel (atelocollagen/glycerol/pullulan [Col/Gly/Pul] gel) that is moldable and injectable with high adhesive qualities was created by employing a straightforward technique that involved the introduction of Gly and Pul. This study aimed to characterize the internal morphology and chemical composition of the Col/Gly/Pul gel, as well as to verify its osteogenic properties through in vivo and in vitro experiments. When compared to a standard pure Col hydrogel, this material is more adaptable to the complexity of the local environment of bone defects and the apposition of irregularly shaped flaws due to its greater mechanical strength, injectability, and moldability. Overall, the Col/Gly/Pul gel is an implant that shows great potential for the treatment of complex bone defects and the enhancement of bone regeneration.

Two Novel Membranes Based on Collagen and Polyphenols for Enhanced Wound Healing

Two novel membranes based on collagen and two polyphenols, taxifolin pentaglutarate (TfG5) and a conjugate of taxifolin with glyoxylic acid (DfTf), were prepared. Fourier transform infrared spectroscopy examination confirmed the preservation of the triple helical structure of collagen. A scanning electron microscopy study showed that both materials had a porous structure. The incorporation of DfTf into the freeze-dried collagen matrix increased the aggregation of collagen fibers to a higher extent than the incorporation of TfG5, resulting in a more compact structure of the material containing DfTf. It was found that NIH/3T3 mouse fibroblasts were attached to, and relatively evenly spread out on, the surface of both newly obtained membranes. In addition, it was shown that the membranes enhanced skin wound healing in rats with a chemical burn induced by acetic acid. The treatment with the materials led to a faster reepithelization and granulation tissue formation compared with the use of other agents (collagen without polyphenols and buffer saline). It was also found that, in the wound tissue, the level of thiobarbituric acid reactive substances (TBARS) was significantly higher and the level of low-molecular-weight SH-containing compounds (RSH) was significantly lower than those in healthy skin, indicating a rise in oxidative stress at the site of injury. The treatment with collagen membranes containing polyphenols significantly decreased the TBARS level and increased the RSH level, suggesting the antioxidant/anti-inflammatory effect of the materials. The membrane containing TfG5 was more effective than other ones (the collagen membrane containing DfTf and collagen without polyphenols). On the whole, the data obtained indicate that collagen materials containing DfTf and TfG5 have potential as powerful therapeutic agents for the treatment of burn wounds.

Aggregation-Disruption-Induced Multi-Scale Mediating Strategy for Anticoagulation in Blood-Contacting Devices

Minimally invasive blood-contacting interventional devices are increasingly used to treat cardiovascular diseases. However, the risk of device-related thrombosis remains a significant concern, particularly the formation of cycling thrombi, which pose life-threatening risks. To better understand the interactions between these devices and blood, the initial stages of coagulation contact activation on extrinsic surfaces are investigated. Direct force measurements reveals that activated contact factors stimulate the intrinsic coagulation pathway and promote surface crosslinking of fibrin. Furthermore, fibrin aggregation is disrupted by surface-grafted inhibitors, as confirmed by ex vivo coagulation tests. An engineered serum protein with zwitterion grafts to resist the deposition of biological species such as fibrin, platelets, and red blood cells is also developed. Simultaneously, a protease inhibitor-based coacervate is incorporated into the coating to inhibit the intrinsic pathway effectively. The loaded coacervate can be released and reloaded through modulation of catechol-amine interactions, facilitating material regeneration. The strategy offers a novel multi-scale mediation strategy that simultaneously inhibits nanoscale coagulation factors and resists microscale thrombus aggregation, providing a long-term solution for anticoagulation in blood-contacting devices.

A nondestructive technique for the sex identification of third instar Cochliomyia macellaria larvae

Forensic entomology plays an important role in medicolegal investigations by using insects, primarily flies, to estimate the time of colonization. This estimation relies on the development of the flies found at the (death) scene and can be affected (and sometimes corrected) by external factors, such as temperature and humidity, and internal factors, such as species and sex. This study leverages infrared (IR) spectroscopy combined with machine learning models-Partial Least Squares Discriminant Analysis (PLS-DA) and eXtreme Gradient Boosting trees Discriminant Analysis (XGBDA)-to differentiate between male and female Cochliomyia macellaria larvae, commonly found on human remains. Significant vibrational differences were detected in the infrared spectra of third instar C. macellaria larvae, with distinct peaks showing variations in relative absorbance between sexes, suggesting differences in biochemical compositions such as cuticular proteins and lipids. The application of PLS-DA and XGBDA yielded high classification accuracies of about 94% and 96%, respectively, with female spectra consistently having higher sensitivity than males. This non-destructive approach offers the potential to refine supplemental post-mortem interval estimations significantly, enhancing the accuracy of forensic analyses.

Versatile Keratin Fibrous Adsorbents with Rapid-Response Shape-Memory Features for Sustainable Water Remediation

Biodegradable shape-memory polymers derived from protein substrates are attractive alternatives with strong potential for valorization, although their reconstruction remains a challenge due to the poor processability and inherent instability. Herein, based on Maillard reaction and immobilization, a feather keratin fibrous adsorbent featuring dual-response shape-memory is fabricated by co-spinning with pullulan, heating, and air-assisted spraying ZIF-8-NH2. Maillard reaction between the amino group of keratin and the carbonyl group of pullulan improves the mechanics and thermal performance of the adsorbent. ZIF-8-NH2 immobilization endows the adsorbent with outstanding multipollutant removal efficiency (over 90%), water stability, and photocatalytic degradation and sterilization performance. Furthermore, the adsorbent can be folded to 1/12 of its original size to save space for transportation and allow for rapid on-demand unfolding (12 s) upon exposure to water and ultraviolet irradiation to facilitate the adsorption and photocatalytic activity with a larger water contact area. This research provides new insight for further applications of keratin-based materials with rapid shape-memory features.

A review of valorization of agricultural waste for the synthesis of cellulose membranes: Separation of organic, inorganic, and microbial pollutants

Agricultural waste presents a significant environmental challenge due to improper disposal and management practices, contributing to soil degradation, biodiversity loss, and pollution of water and air resources. To address these issues, there is a growing emphasis on the valorization of agricultural waste. Cellulose, a major component of agricultural waste, offers promising opportunities for resource utilization due to its unique properties, including biodegradability, biocompatibility, and renewability. Thus, this review explored various types of agricultural waste, their chemical composition, and pretreatment methods for cellulose extraction. It also highlights the significance of rice straw, sugarcane bagasse, and other agricultural residues as cellulose-rich resources. Among the various membrane fabrication techniques, phase inversion is highly effective for creating porous membranes with controlled thickness and uniformity, while electrospinning produces nanofibrous membranes with high surface area and exceptional mechanical properties. The review further explores the separation of pollutants including using cellulose membranes, demonstrating their potential in environmental remediation. Hence, by valorizing agricultural residues into functional materials, this approach addresses the challenge of agricultural waste management and contributes to the development of innovative solutions for pollution control and water treatment.

Development of hybrid polyvinylpyrrolidone/carboxymethyl cellulose/collagen incorporated oregano scaffolds via direct ink write printing for potential wound healing applications

Additive manufacturing can develop regenerative scaffolds for wound healing. 3D printing offers meticulous porosity, mechanical integrity, cell adhesion and cost-effectiveness. Herein, we prepared ink composed of carboxymethyl cellulose (CMC), polyvinylpyrrolidone (PVP), collagen, and oregano extract for the fabrication of tissue constructs. The blend was optimized to form a homogeneous ink and rheological characterization demonstrated shear thinning behavior. The scaffolds were printed using Direct Ink Write (DIW) at a flow speed of 4 mm3/s and a layer height of 0.18 mm. The fabricated scaffolds demonstrated an ultimate tensile strength (UTS) and toughness of 730 KPa and 2.72 MJ/m3, respectively. Scanning Electron Microscopy (SEM) revealed an average pore size of 300 ± 30 μm. Fourier transform infrared spectroscopy (FTIR) analysis confirmed that all materials were present. The contact angle of the composite scaffold was 68° ± 1°. Moreover, the scaffolds presented 82 % mass loss (degradation) in phosphate buffer saline (PBS) over 14 days. The composite scaffold exhibited inhibition zones of 9 mm and 12 mm against Staphylococcus aureus and Escherichia coli, respectively. The PVP/CMC/collagen/oregano 3D printed scaffolds exhibited excellent biocompatibility with the mesenchymal stem cells and humman dermal fibroblast cells, confirmed by water-soluble tetrazolium - 8 (WST-8) assay (test conducted for 7 days). The enhanced angiogenic potential of said scaffold was assesed by release of vascular endothelial growth factor followed by further validation through in-vivo CAM assay. Thus, confirming suitability for the potential wound healing application.

Quantifying the effects of repeated dyeing: Morphological, mechanical, and chemical changes in human hair fibers

As hair dyeing gains popularity across all age groups, concerns about the potential damage caused by chemical treatments are also on the rise. Chemical dyes have a multifaceted impact on hair fibers, affecting their morphology, physical structure, and protein composition. In a comprehensive study, we investigated the alterations in morphological and mechanical properties, as well as the chemical composition of hair fibers following continuous dyeing. Our analysis employed various techniques, including atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy, and tensile strength measurements. To assess the cumulative damage resulting from repeated dyeing, we progressively increased the number of dyeing up to 10. Surprisingly, even a single dyeing session inflicted noticeable harm on the hair. However, the detrimental effects escalated significantly when hair underwent three or more consecutive dye treatments. While the mechanical properties and protein composition exhibited non-linear changes with increasing the number of dyeing, we observed that nanoscale damage to the cuticle surface intensified proportionally with the number of dyeing. These results highlight the critical need to consider the impacts of hair dyeing practices on both the health and the structural integrity of hair.

Energy-Efficient and Effective MCF-7 Cell Ablation and Electrothermal Therapy Enabled by M13-WS2-PEG Nanostructures

Thermal agents (TAs) have exhibited promise in clinical tests when utilized in cancer thermal therapy (TT). While rapid degradation of TAs may address safety concerns, it limits the thermal stability required for effective treatment. TAs, which possess exceptional thermal stability, experience gradual deterioration. There are few approaches that effectively address the trade-off between improving thermal stability and simultaneously boosting material deterioration. Here, we control the thermal character of tungsten disulfide (WS2)-based 2D materials by utilizing an M13 phage through Joule heating (the M13-WS2-PEG nanostructures were generated and termed a tripartite (T) nanostructure), and developed a T nanostructure-driven TT platform (we called it T-TT) for efficient thermal ablation of clinically relevant MCF-7 cells. A relative cell viability of ~59% was achieved, as well as onset time of degradation of ~0.5 week. The T-TT platform also discloses an energy density of 5.9 J/mL. Furthermore, the phage-conjugated WS2 can be utilized to achieve ultrasound imaging for disease monitoring. Therefore, this research not only presents a thermal agent that overcomes TA limitations, but also demonstrates a practical application of WS2-type material system in ultra-energy efficient and effective cancer therapy.

Photo-crosslinked chitosan-gelatin xerogel-like coating onto "cold" plasma functionalized poly(lactic acid) film as cell culture support

This paper reports on biofunctionalisation of a poly(lactic acid) (PLA) film by surface activation through cold plasma treatment followed by coating with a chitosan-gelatin xerogel. The UV cross-linking of the xerogel precursor was simultaneously performed with the fixation onto the PLA support. This has a strong effect on surface properties, in terms of wettability, surface free energy, morphology and micromechanical features. The hydrophilic - hydrophobic character of the surface, determined by contact angle measurements, was tuned along the process, passing from moderate hydrophobic PLA to enhanced hydrophilic plasma activated surface, which favors coating adhesion, then to moderate hydrophobic chitosan-gelatin coating. The coating has a Lewis amphoteric surface, with a porous xerogel-like morphology, as revealed by scanning electron microscopy images. By riboflavin mediated UV cross-linking the chitosan-gelatin coating becomes high adhesive and with a more pronounced plasticity, as shown by AFM force-distance spectroscopy. Thus prepared surface-coated PLA supports were successfully tested for growth of dermal fibroblasts, which are known for their induction potential of chondrogenic cells, which is very important in cartilage tissue engineering.

Application of ATR-FTIR Spectroscopy for Analysis of Salt Stress in Brussels Sprouts

Salt stress is one of the environmental stresses that significantly reduces crop productivity and quality worldwide. Methods to overcome salt stress include developing salt-resistant crops by inserting various resistance genes or to diagnosing and responding to the effects of salt stress at an early stage. In this study, we investigate the effects of salinity stress on growth, photosynthetic efficiency, and metabolic changes in Brussels sprouts (Brassica oleracea var. gemmifera). Fresh weight and leaf area decreased significantly with increasing NaCl concentration, indicating that salinity stress has a detrimental effect on plant growth. However, chlorophyll fluorescence parameters did not show significant changes, suggesting that photosynthetic efficiency was not significantly affected over 10 days. Fourier transform infrared (FTIR) spectroscopy revealed notable metabolic adjustments, especially in lipids, plastids, proteins, and carbohydrates, indicating biosynthesis of protective compounds such as anthocyanins and proline in response to salinity stress. Pearson correlation analysis confirmed a strong relationship between NaCl concentration and the observed physiological and metabolic changes. The findings highlight the potential of FTIR spectroscopy as a non-destructive tool for early detection of salinity stress and timely intervention to improve crop resilience and yield. This study highlights the widespread application of FTIR spectroscopy in agricultural research to manage abiotic stresses in crops.

Methacrylated Wood Flour-Reinforced Gelatin-Based Gel Polymer as Green Electrolytes for Li-O2 Batteries

With its very high theoretical energy density, the Li-O2 battery could be considered a valid candidate for future advanced energy storage solutions. However, the challenges hindering the practical application of this technology are many, as for example electrolyte degradation under the action of superoxide radicals produced upon cycling. In that frame, a gel polymer electrolyte was developed starting from waste-derived components: gelatin from cold water fish skin, waste from the fishing industry, and wood flour waste from the wood industry. Both were methacrylated and then easily cross-linked through a one-pot ultraviolet (UV)-initiated free radical polymerization, directly in the presence of the liquid electrolyte (0.5 M LiTFSI in DMSO). The wood flour works as cross-linking points, reinforcing the mechanical properties of the obtained gel polymer electrolyte, but it also increases Li-ion transport properties with an ionic conductivity of 3.3 mS cm-1 and a transference number of 0.65 at room temperature. The Li-O2 cells assembled with this green gel polymer electrolyte were able to perform 180 cycles at 0.1 mA cm-2, at a fixed capacity of 0.2 mAh cm-2, under a constant O2 flow. Cathodes post-mortem analysis confirmed that this electrolyte was able to slow down solvent degradation, but it also revealed that the higher reversibility of the cells could be explained by the formation of Li2O2 in the amorphous phase for a higher number of cycles compared to a purely gelatin-based electrolyte.

Antioxidant Marine Hydrolysates Isolated from Tuna Mixed Byproducts: An Example of Fishery Side Streams Upcycling

The aim of this research is to propose simple and scalable processes to obtain bioactive peptides extensively hydrolyzed starting from a tuna mixed biomass. The upcycling of this powdered biomass is challenging since it comes from the unsorted industrial side streams of the tuna canning process (cooked residues from fillet trimming) after a patented mild dehydration useful for preventing its degradation until its exploitation. Two different protocols were proposed, with and without the inclusion of an exogenous enzyme (Enzymatic-Assisted Extraction, EAE), with no relevant differences in yields (24% vs. 22%) and a comparable amino acid composition. Nevertheless, the former protocol (with EAE) provided peptides with an average molecular weight of 1.3 kDa, and the second one (without EAE) provided peptides with an average molecular weight of 2.2 kDa. The two corresponding types of tuna protein hydrolysates (Enzymatic Hydrolysates (EH) and Non-Enzymatic Hydrolysates (NEH)) were characterized by proximate compositions, pH, color profile, amino acid analysis, FTIR spectra, and molecular weight distribution. In addition, several biological analyses were performed to assess their potential use as nutraceutical supplements: special attention has been paid to antioxidant activity using three different methods to quantify it. EH showed the most promising antioxidant activity which could be exploited also in other fields (e.g., biomaterials, cosmetics).

Construction and characterization of Zn-WPH-COS complex nanoparticles with improved zinc bioavailability

Precipitation was an important obstacle to improving zinc's bioavailability. Therefore, zinc-whey protein hydrolysate-chitosan oligosaccharide (Zn-WPH-COS) complexes (167 nm) were prepared by linking Zn-WPH (zinc: 18.4%) with COS (1:1, 2 h) to enhance zinc's bioaccessibility. Fourier-transform infrared showed Zn-WPH formed with zinc replaced hydrogen (from 3274 to 3279 cm-1) and reacted with COO- (C-N: from 1394 to 1402 cm-1), a new peak at 1025 cm-1 proved COS can be successful cross-linked (Zn-WPH-COS). Fluorescence spectra showed zinc and COS reduced WPH hydrophobicity (28.0 and 39.0%, respectively). Circular dichroism showed zinc decreased WPH α-helix (from 13.7 to 11.5%), in contrast with COS to Zn-WPH. Zinc solubility and dialyzability were increased (64.5/ 54.2% vs 50.2/ 41.2% vs 29.5/ 21.7%) in Zn-WPH-COS, compared with Zn-WPH and ZnSO4·7H2O, respectively, due to the smallest size (167 nm) and COS protection on Zn-WPH (gastric digestion). These results indicate Zn-WPH-COS could significantly improve the digestion and absorption of zinc.

Comparison of the Impact of NaIO4-Accelerated, Cu2+/H2O2-Accelerated, and Novel Ion-Accelerated Methods of Poly(l-DOPA) Coating on Collagen-Sealed Vascular Prostheses: Strengths and Weaknesses

Sensitive biomaterials subjected to surface modification require delicate methods to preserve their structures and key properties. These include collagen-sealed polyester vascular prostheses. For their functionalization, coating with polycatecholamines (PCAs) can be used. PCAs change some important biological properties of biomaterials, e.g., hydrophilicity, bioactivity, antibacterial activity, and drug binding. The coating process can be stimulated by oxidants, organic solvents, or process conditions. However, these factors may change the properties of the PCA layer and the matrix itself. In this work, collagen-sealed vascular grafts were functionalized with a poly(l-DOPA) (PLD) layer using novel seawater-inspired ion combination as an accelerator, compared to the sodium periodate, Cu2+/H2O2 mixture, and accelerator-free reference methods. Then, poly(l-DOPA) was used as the interface for antibiotic binding. The coated prostheses were characterized (SEM, FIB-SEM, FTIR, UV/vis), and their important functional parameters (mechanical, antioxidant, hemolytic, and prothrombotic properties, bioactivity, stability in human blood and simulated body fluid (SBF), antibiotic binding, release, and antibacterial activity) were compared. It was found that although sodium periodate increased the strength and drug-binding capacity of the prosthesis, it also increased the blood hemolysis risk. Cu2+/H2O2 destabilized the mechanical properties of the coating and the graft. The seawater-inspired ion-accelerated method was efficient, stable, and matrix- and human blood-friendly, and it stimulated hydroxyapatite formation on the prosthesis surface. The results lead to the conclusion that selection of the PCA formation accelerator should be based on a careful analysis of the biological properties of medical devices. They also suggest that the ion-accelerated method of PLD coating on medical devices may be highly effective and safer than the oxidant-accelerated coating method.

Mechanistic study of the stabilization of dentin-bonded restorative interfaces via collagen reinforcement by multi-acrylamides

Hydrolytically and enzymatically-stable multi-acrylamides have been proposed to increase the long-term durability of dental adhesive interfaces as alternatives to methacrylates. The aim of this study was to investigate the mechanical and biochemical properties of experimental adhesives containing multi-functional acrylamides concerning collagen reinforcement and metalloproteinases (MMP) activity. Multi-functional acrylamides, TMAAEA (Tris[(2-methylaminoacryl) ethylamine) and DEBAAP (N,N-Diethyl-1,3-bis(acrylamido) propane), along with the commercially available DMAM (N,N-dimethylacrylamide) (monofunctional acrylamide) and HEMA (2-Hydroxyethyl methacrylate) (monofunctional methacrylate - control) were tested for stability against enzymatic hydrolysis by cholesterol esterase/pseudocholinesterase (PC/PCE) solutions for up to 30 days. Collagen-derived substrate and gelatin zymography were performed to examine the effect of the compounds on the biological activity of human recombinant and dentin-extracted gelatinases MMP-2 and MMP-9. In situ zymography was carried out by fluorescent collagen degradation combined with confocal microscopy analysis. Hydroxyproline content was measured in collagen derived from dentin extracts though reaction with Ehrlich's reagent p-dimethylaminobenzaldehyde (DMAB), generating a stable chromophore measured at 550 nm. Storage shear modulus of demineralized dentin discs treated with the tested compounds was measured by oscillatory rheometry, in order to investigate potential collagen reinforcement. FT-IR was performed to determine qualitative differences in collagen based on observed changes in amide bands. The results were analyzed by ANOVA/Tukey's test (α = 0.05). Multi-acrylamides survived 30 days of incubation in cholinesterase/pseudo-cholinesterase (PC/PCE) solutions, while HEMA showed approximately 70 % overall degradation. Incubation with multi-acrylamides reduced collagen degradation as evidenced by the reduced hydroxyproline levels and by the 30 % increase inshear storage modulus. Biochemical and zymography assays showed no noticeable inhibition of recombinant and extracted MMPs enzymatic activity. The infra-red spectroscopy results for multi-functional acrylamides treated samples demonstrated shifts of the amide II bonds and marked increase in intensity of the bands 1200 cm-1, which may indicate partial collagen denaturation and some degree of cross-linking of the compounds with collagen, respectively. The multi-acrylamides exhibited not only comparable mechanical properties but also demonstrated significantly enhanced biochemical stability when compared to the widely used methacrylate control. Clinical relevance: These findings highlight the potential of multi-acrylamides to increase the bonding stability to tissues and, ultimately, contribute to the longevity of dental restorations.

Combining spectrum and machine learning algorithms to predict the weathering time of empty puparia of Sarcophaga peregrine (Diptera: Sarcophagidae)

The weathering time of empty puparia could be important in predicting the minimum postmortem interval (PMImin). As corpse decomposition progresses to the skeletal stage, empty puparia often remain the sole evidence of fly activity at the scene. In this study, we used empty puparia of Sarcophaga peregrina (Diptera: Sarcophagidae) collected at ten different time points between January 2019 and February 2023 as our samples. Initially, we used the scanning electron microscope (SEM) to observe the surface of the empty puparia, but it was challenging to identify significant markers to estimate weathering time. We then utilized attenuated total internal reflectance Fourier transform infrared spectroscopy (ATR-FTIR) to detect the puparia spectrogram. Absorption peaks were observed at 1064 cm-1, 1236 cm-1, 1381 cm-1, 1538 cm-1, 1636 cm-1, 2852 cm-1, 2920 cm-1. Three machine learning models were used to regress the spectral data after dimensionality reduction using principal component analysis (PCA). Among them, eXtreme Gradient Boosting regression (XGBR) showed the best performance in the wavenumber range of 1800-600 cm-1, with a mean absolute error (MAE) of 1.20. This study highlights the value of refining these techniques for forensic applications involving entomological specimens and underscores the considerable potential of combining FTIR and machine learning in forensic practice.

Biomolecular alterations temporally anticipate microarchitectural modifications of collagen in oral tongue squamous cell carcinoma

High resolution analysis of collagen bundles could provide information on tumor onset and evolution. This study was focused on the microarchitecture and biomolecular organization of collagen bundles in oral tongue squamous cell carcinoma (OTSCC). Thirty-five OTSCC biopsy samples were analyzed by synchrotron-based phase-contrast microcomputed tomography and Fourier transform infrared imaging (FTIRI) spectroscopy. PhC-microCT evidenced the presence of reduced and disorganized collagen in the tumor area compared to the extratumoral (ExtraT) one. FTIRI also revealed a reduction of folded secondary structures in the tumor area, and highlighted differences in the peritumoral (PeriT) areas in relation with the OTSCC stage, whereby a significantly lower amount of collagen with less organized fibers was found in the PeriT stroma of advanced-OTSCC stages. Interestingly, no significant morphometrical mismatches were detected in the same region by PhC-microCT analysis. These results suggest that biomolecular alterations in the OTSCC stroma temporally anticipate structural modifications of collagen bundle microarchitecture.

The Role of the Molecular Encapsulation Effect in Stabilizing Hydrogen-Bond-Rich Gel-State Lithium Metal Batteries

Gel-state polymer electrolytes with superior mechanical properties, self-healing abilities and high Li+ transference numbers can be obtained by in situ polymerization of monomers with hydrogen-bonding moieties. However, it is overlooked that the active hydrogen atoms in hydrogen-bond donors experience displacement reactions with lithium metal in lithium metal batteries (LMBs), leading to corrosion of the lithium metal. Herein, it is discovered that the addition of hydrogen-bond acceptors to hydrogen-bond-rich gel-state electrolytes modulates the chemical activity of the active hydrogen atoms via the formation of hydrogen-bonded intermolecular interactions. The characterizations reveal that the added hydrogen-bond acceptors encapsulate the active hydrogen atoms to suppress the interfacial chemical corrosions of lithium metals, thereby enhancing the chemical stability of the polymer structure and interphase. With the employment of this strategy, a 1.1 Ah LiNi0.8Co0.1Mn0.1O2/Li metal pouch cell achieves stable cycling with 96.3 % capacity retention at 100 cycles. This new approach indicates a feasible path for achieving in situ polymerization of highly stable gel-state-based LMBs.

Mattel's ©Barbie: Preventing Plasticizers Leakage in PVC Artworks and Design Objects through Film-Forming Solutions

The main conservation problem of p-PVC artworks is phthalate-based plasticizer migration. Phthalate migration from the bulk to the surface of the materials leads to the formation of a glossy and oily film on the outer layers, ultimately reducing the flexibility of the material. This study aimed to develop a removable coating for the preservation of contemporary artworks and design objects made of plasticized polyvinyl chloride (p-PVC). Several coatings incorporating chitosan, collagen, and cellulose ethers were assessed as potential barriers to inhibiting plasticizer migration. Analytical techniques including optical microscopy (OM), ultraviolet/visible/near-infrared spectroscopy (UV/Vis/NIR), Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), and scanning electron microscopy (SEM) were utilized to evaluate the optical and chemical stability of selected coating formulations applied to laboratory p-PVC sheet specimens. Subsequently, formulations were tested on a real tangible example of a design object, ©Barbie doll, characterized by the prevalent issue of plasticizer migration. Furthermore, the results obtained with the tested formulations were evaluated by a group of conservators using a tailored survey. Finally, a suitable coating formulation capable of safeguarding plastic substrates was suggested.

A Novel Collagen Aerogel with Relevant Features for Topical Biomedical Applications

Collagen-based aerogels have great potential for topical biomedical applications. Collagen's natural affinity with skin, biodegradability, and gelling behavior are compelling properties to combine with the structural integrity of highly porous matrices in the dry form (aerogels). This work aimed to produce a novel collagen-based aerogel and to perform the material's solid-state and physicochemical characterization. Aerogels were obtained by performing different solvent exchange approaches of a collagen-gelled extract and drying the obtained alcogels with supercritical CO2. The resulting aerogels showed a sponge-like structure with a relatively dense mesoporous network with a specific surface area of 201-203 m2/g, a specific pore volume of 1.08-1.15 cm3/g, and a mean pore radius of ca. 14.7 nm. Physicochemical characterization confirmed that the obtained aerogels are composed of pure collagen, and the aerogel production process does not impact protein tertiary structure. Finally, the material swelling behavior was assessed at various pH values (4, 7, and 10). Collagen aerogels presented a high water uptake capacity up to ~2700 wt. %, pH-dependent stability, and swelling behavior in aqueous media. The results suggest that this collagen aerogel could be a promising scaffold candidate for topical biomedical applications.

Damage-Free Silica Coating for Colloidal Nanocrystals Through a Proactively Water-Generating Amidation Reaction at High Temperature

Silica is a promising shell coating material for colloidal nanoparticles due to its excellent chemical inertness and optical transparency. To encapsulate high-quality colloidal nanocrystals with silica shells, the silane coupling hydrolysis is currently the most effective approach. However, this reaction requires water, which often adversely affects the intrinsic physicochemical properties of nanocrystals. Achieving a damage-free silica encapsulation process to nanocrystals by hydrolysis is a huge challenge. Here, a novel strategy is developed to coat colloidal nanocrystals with a denser silica shell via a proactively water-generating reaction at high temperature. In this work, water molecules are continuously and proactively released into the reaction system through the amidation reaction, followed by in situ hydrolysis of silane, completely avoiding the impacts of water on nanocrystals during the silica coating process. In this work, water sensitive perovskite nanocrystals (CsPbBr3) are selected as the typical colloidal nanocrystals for silica coating. Notably, this high-temperature in situ encapsulation technology greatly improves the optical properties of nanocrystals, and the silica shells exhibit a denser structure, providing nanocrystals with better protection. This method overcomes the challenge of the influence of water on nanocrystals during the hydrolysis process, and provides an important reference for the non-destructive encapsulation of colloidal nanocrystals.

Structural Characterization of the Staphylococcus aureus Targeting Lectin Peptides from Garlic (Allium sativum L) by Liquid Nitrogen Grinding Coupled with the Proteomic and Antimicrobial Mechanism Analysis

Garlic has long been used as an antimicrobial spice and herbal remedy. The aim of this study was to isolate the antimicrobial agent in garlic water extract against Staphylococcus aureus (S. aureus) and investigate its antimicrobial mechanism. By an activity-guided separation, garlic lectin-derived peptides (GLDPs) with main molecular weight of around 12 kDa were extracted by liquid nitrogen grinding and identified with high bactericidal activity toward S. aureus, and the MIC was determined as 24.38 μg/mL. In-gel digestion-based proteomic analysis indicated that the peptide sequences were highly identical to the B strain of garlic protein lectin II. Structure analysis suggested that the secondary structure was strongly affected by lyophilization and thus resulted in the inactivation of GLDPs (P < 0.05). Mechanism study revealed that treatment of GLDPs resulted in cell membrane depolarization in a dose-dependent manner, and the disruptions of the cell wall and membrane integrities were observed under electric microscopies. GLDPs could successfully dock with cell wall component lipoteichoic acid (LTA) via van der Waals and conventional bonds in molecular docking analysis. These results suggested that GLDPs were responsible for the S. aureus targeting activity and might be promising candidates for antibiotic development against bacterial infection.

Label-free differentiation of functional zones in mature mouse placenta using micro-Raman imaging

In histopathology, it is highly crucial to have chemical and structural information about tissues. Additionally, the segmentation of zones within a tissue plays a vital role in investigating the functions of these regions for better diagnosis and treatment. The placenta plays a vital role in embryonic and fetal development and in diagnosing some diseases associated with its dysfunction. This study provides a label-free approach to obtain the images of mature mouse placenta together with the chemical differences between the tissue compartments using Raman spectroscopy. To generate the Raman images, spectra of placental tissue were collected using a custom-built optical setup. The pre-processed spectra were analyzed using statistical and machine learning methods to acquire the Raman maps. We found that the placental regions called decidua and the labyrinth zone are biochemically distinct from the junctional zone. A histologist performed a comparison and evaluation of the Raman map with histological images of the placental tissue, and they were found to agree. The results of this study show that Raman spectroscopy offers the possibility of label-free monitoring of the placental tissue from mature mice while simultaneously revealing crucial structural information about the zones.

Effects of Grinding Methods of Tartary Buckwheat Leaf Powder on the Characteristics and Micromorphology of Wheat Dough

The functional components in tartary buckwheat leaf powder can give flour products higher nutritional value. To comprehensively realize the high-value utilization of tartary buckwheat and its by-products, electric stone mill powder (EMP), ultra-fine mill powder (UMP), steel mill powder (SMP), and grain mill powder (GMP) from tartary buckwheat leaves were used in the preparation of wheat dough, and this was used to explore their effects on dough properties and protein microstructure. With an increase in tartary buckwheat leaf powder, the hydration characteristics, protein weakening rate, and starch gelatinization characteristics of the dough changed, and the water holding capacity and swelling capacity decreased. The retrogradation value increased, which could prolong the shelf life of related products. The water solubility of the dough showed an upward trend and was the lowest at 10% UMP. The addition of UMP produced a more uniform dough stability time and the lowest degree of protein weakening, which made the dough more resistant to kneading. An increasing amount of tartary buckwheat leaf powder augmented the free sulfhydryl content of the dough and decreased the disulfide bond content. The disulfide bond content of the dough containing UMP was higher than that of the other doughs, and the stability of the dough was better. The peaks of the infrared spectrum of the dough changed after adding 10% UMP and 20% EMP. The content of α-helical structures was the highest at 10% UMP, and the content of ordered structures was enhanced. The polymerization of low molecular weight proteins to form macromolecular polymers led to a reduction in surface hydrophobic regions and the aggregation of hydrophobic groups. The SEM results also demonstrated that at 10% tartary buckwheat leaf powder, the addition of UMP was significantly different from that of the other three leaf powders, and at 20%, the addition of EMP substantially altered the structure of the dough proteins. Considering the effects of different milling methods and different added amounts of tartary buckwheat leaf powder on various characteristics of dough, 10% UMP is the most suitable amount to add to the dough.

Water-Insoluble, Thermostable, Crosslinked Gelatin Matrix for Soft Tissue Implant Development

In this present study, the material science background of crosslinked gelatin (GEL) was investigated. The aim was to assess the optimal reaction parameters for the production of a water-insoluble crosslinked gelatin matrix suitable for heat sterilization. Matrices were subjected to enzymatic degradation assessments, and their ability to withstand heat sterilization was evaluated. The impact of different crosslinkers on matrix properties was analyzed. It was found that matrices crosslinked with butanediol diglycidyl ether (BDDE) and poly(ethylene glycol) diglycidyl ether (PEGDE) were resistant to enzymatic degradation and heat sterilization. Additionally, at 1 v/v % crosslinker concentration, the crosslinked weight was lower than the starting weight, suggesting simultaneous degradation and crosslinking. The crosslinked weight and swelling ratio were optimal in the case of the matrices that were crosslinked with 3% and 5% v/v BDDE and PEGDE. FTIR analysis confirmed crosslinking, and the reduction of free primary amino groups indicated effective crosslinking even at a 1% v/v crosslinker concentration. Moreover, stress-strain and compression characteristics of the 5% v/v BDDE crosslinked matrix were comparable to native gelatin. Based on material science measurements, the crosslinked matrices may be promising candidates for scaffold development, including properties such as resistance to enzymatic degradation and heat sterilization.

A comprehensive study of sous-vide cooked Korat chicken breast processed by various conditions: texture, compositional/structural changes, and consumer acceptance

Korat chicken (KC) is a slow-growing crossbreed renowned for its excellent growth and firm texture. This study investigated the effect of various sous-vide (SV) conditions (60 and 70°C, 1-3 h) on their texture, protein structure and degradation, as well as consumer acceptability, with the traditional boiling served as control. Texture showed significant improvement under all SV conditions compared to the control, as demonstrated by increased water holding capacity (WHC), cooking loss, and decreased shear force, hardness, and chewiness (P < 0.05). These changes corresponded to the higher sensory scores (P < 0.05). Among the SV samples, increased temperatures and longer cooking times led to higher degradation of myofibrils and connective tissue, as evidenced by a decrease in water-, salt-soluble proteins, and soluble collagen (P < 0.05). These findings aligned with the scanning electron microscopy (SEM) results, which showed a looser muscle structure in the meat under more intense cooking conditions. Based on synchrotron radiation-based Fourier transform infrared (SR-FTIR) results, a gradual increase in antiparallel forms within the amide I bands (1,700-1,600 cm-1) of the total spectra with higher temperature and longer cooking times was observed (P < 0.05), while the fluctuations were observed in the changes of α-helix, β-sheet, and β-turn structures. This suggested that the antiparallel structure represented a looser configuration developing during intense SV cooking. Combined with the principal component analysis (PCA) results, the findings indicated that the suitable SV condition for KC breast meat was 70°C for varying durations (1-3 h), as it showed the strongest correlation with sensory scores, particularly in terms of tenderness. In summary, these findings provided a better understanding of molecular changes and discovered SV conditions to enhance the texture quality of the KC meat.

Multimodal characterization of the collagen hydrogel structure and properties in response to physiologically relevant pH fluctuations

pH fluctuations within the extracellular matrix (ECM) and its principal constituent collagen, particularly in solid tumors and chronic wounds, may influence its structure and function. Whereas previous research examined the impact of pH on collagen fibrillogenesis, this study focuses on determining how pH fluctuations affect collagen hydrogels that mimic the physiological ECM. Utilizing a type I collagen hydrogel, we examined the influence of pH fluctuations on its structure, properties, and function while keeping the collagen hydrated. We show that collagen's secondary structure remains unaltered during pathologically relevant microenvironmental pH changes. By employing cryo scanning electron microscopy and artificial intelligence-assisted image analysis, we show that at physiological pH, collagen hydrogel presents densely packed, aligned, and elongated fibrils, which upon a decrease to pH 6.5, are transformed into shorter, sparser, and disoriented fibrils. The collagen possesses a higher storage modulus yet a lower permeability at pH 7 and 7.8 compared with pH 6.5 and 7.4. Exposing acidified collagen to a basic buffer reinstates its native structure and viscoelastic properties. Our study offers an innovative approach to analyze and characterize perturbations in hydrated collagen-based systems with potential implications for better understanding and combating disease progression. STATEMENT OF SIGNIFICANCE: As the main component of the extracellular matrix, collagen undergoes conformational changes associated with pH changes during disease. We analyze the impact of pH on pre-formed collagen fibers mimicking healthy tissues subjected to disease, and do not focus on the more studied fibrillogenesis process. Using cryogenic SEM, which allowed imaging close to the native state, we show that even minor fluctuations in the pH affect the collagen thickness, length, fiber alignment, and rheological properties. Following exposure to acidic pH, the collagen had short fibers, lacked orientation, and had low mechanical strength. This acidic collagen restored its original properties after returning to a neutral pH. These findings can help determine how pH changes can be modulated to restore healthy collagen properties.

The influence of pH and salt concentration on the microstructure and mechanical properties of meniscus extracellular matrix-derived implants

Meniscus-related injuries are a common orthopedic challenge with an increasing incidence in the population. While the preservation of viable meniscal tissue is the preferred approach in repair strategies, complex or total traumatic lesions may require alternative therapeutic approaches such as meniscal reconstruction using allografts or engineered equivalents. Although clinical studies suggest promising outcomes with the use of acellular implants, further development is needed to improve their biological and mechanical requirements. Decellularized extracellular matrix (dECM) derived from menisci is a promising biomaterial for meniscus tissue engineering due to its recapitulation of the native tissue environment and the maintenance of tissue-specific cues. However, the associated mechanical limitations of dECM-derived scaffolds frequently impedes their adoption, requiring additional reinforcement or combining with stiffer biomaterials to increase their load-bearing properties. In this study, decellularized extracellular matrix was extracted and its fibrillation was controlled by adjusting both pH and salt concentrations to fabricate mechanically functional meniscal tissue equivalents. The effect of collagen fibrillation on the mechanical properties of the dECM constructs was assessed, and porcine-derived fibrochondrocytes were used to evaluate in vitro biocompatibility. It was also possible to fabricate meniscus-shaped implants by casting of the dECM and to render the implants suitable for off-the-shelf use by adopting a freeze-drying preservation method. Suture pull-out tests were also performed to assess the feasibility of using existing surgical methods to fix such implants within a damaged meniscus. This study highlights the potential of utilizing ECM-derived materials for meniscal tissue substitutes that closely mimic the mechanical and biological properties of native tissue.