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To augment sustainable tanning, less chrome input, high functional quality leather processed via no restricted substance in processing, and ease to treat the inevitable protein waste generated are the key challenge, and currently, they have become the active part of leather research. Our work covers the synthesis of a formaldehyde-free chromium-incorporated polymeric tanning agent (FF-CIPTA) and its application in a reformed leather processing route which ensures near zero discharge of chromium containing solid waste. The preliminary characterization of FF-CIPTA reveals that the developed product is stable up to pH 5.2, and the particle size distribution ranges from 955 to 1450 nm with 12% Cr2O3 content. The present work significantly reduces the tanning agent input without compromising the thermal stability (103 °C) of the leather because of its multicrosslinking nature. Since the product exhibits a polymeric character, it provides tanning-cum-filling action which in turn reduces the retanning agent consumption in subsequent processes. Scanning electron microscopic study, porosity analysis, and hand assessment results clearly indicate the significant improvement in organoleptic properties. In addition, the process also enjoys the benefits of zero chromium containing solid waste generation, 71.4% reduction in chromium input, and high chromium transfer efficiency (92%) than the conventional process (36%), and 74.4% reduction in total dissolved solids generation. Furthermore, the water consumption and chemical input are reduced by 51.6 and 17%, respectively. Reduction in wastewater treatment cost and a high economic value of chromium-free leather scraps leads to a cumulative gain of US$ 39.84 per ton of raw material processing. Overall, a potential and practical applicability for cleaner and sustainable tanning is well established.

Silica nanoparticles have attracted a huge bioaudience as these are biosafe materials for targeted delivery applications due to their ease of functionalisation, less toxicity, and bio-compatibility. However, poor knowledge of the interaction mechanism between silica nanoparticles and protein causes less development of silica-based fluorescent probes for practical applications. Hence, in this work, the interaction mechanism and structural changes in BSA caused by silica nanoparticles with different functional groups have been studied. First dye-supported silica nanoparticles with hydroxyl terminal (DSN) and amine terminal (DSFN) were synthesized by a modified Stober process. The dye supported on silica nanoparticles resulted in improving the photostability, with less toxicity when compared to the bare dye system. To improve the bioavailability, BSA was conjugated with both hydroxyl (BSA–DSN) and amine functionalised dye supported silica nanoparticles (BSA–DSFN). To understand the structural modification induced by silica with different terminals, nanoparticles were incubated with BSA (Bovine Serum Albumin) for 48 h. Then, the structural changes caused by BSA interacting with silica nanoparticles were evaluated using various techniques such as UV-VIS spectroscopy, fluorescence spectroscopy, CD (circular dichroism), and lifetime measurements. Longer lifetime emphasized the stable photophysical properties of BSA conjugated dye supported silica nanoparticles for live-cell imaging. These interaction studies generated knowledge on structural modification induced by BSA adsorption on silica nanoparticles and its bioavailability for cell imaging. The circular dichroism measurement divulges that the stabilisation of the secondary structure and improved thermal stability of BSA were attained after conjugating with silica nanoparticles. Cell toxicity and imaging results showed that BSA conjugated with amine-functionalised silica nanoparticles BSA@DSFN proved to be an ideal candidate for long-life fluorescent probes for cellular imaging application.

Functionalized nanoparticle cross-linked collagen scaffolds offer improved properties to biomaterials and regenerated tissues, as influence of nanoparticle shape on collagen scaffold has received little attention. The present study evaluates the role of ZnO nanoparticle shape (sphere, rod, hexagonal, needle, flower, star, circular disk, doughnut, and cube) on collagen self-assembly. The nanoparticle was prepared by using coprecipitation method and subsequently functionalized with triethoxysilane poly(amidoamine) dendrimer generation 1 (TES-PAMAM-G1 or G1) on the nanoparticle surface. The self-assembly process of collagen, facilitated by EDC-NHS cross-linking, led to stable ZnO-TES-PAMAM-G1-collagen scaffolds. Physicochemical properties and biocompatibility of scaffolds were analyzed to determine the thermal, mechanical and pore size transformation and cell viability, etc. and obtained results compared against collagen scaffolds with/without EDC-NHS cross-linking. In vivo wound healing activity of ZnO-TES-...

Functionalized metal oxide nanoparticles cross-linked collagen scaffolds are widely used in skin regenerative applications because of their enhanced physicochemical and biocompatibility properties. From the safety clinical trials point of view, there are no reports that have compared the effects of functionalized metal oxide nanoparticles mediated collagen scaffolds for in vivo skin regenerative applications. In this work, triethoxysilane-poly (amido amine) dendrimer generation 3 (TES-PAMAM-G3 or G3)-functionalized spherical shape metal oxide nanoparticles (MO NPs: ZnO, TiO2, Fe3O4, CeO2, and SiO2, size: 12–25 nm) cross-linked collagen scaffolds were prepared by using a self-assembly method. Triple helical conformation, pore size, mechanical strength, and in vitro cell viability of MO-TES-PAMAM-G3-collagen scaffolds were studied through different methods. The in vivo skin regenerative proficiency of MO-TES-PAMAM-G3-collagen scaffolds was analyzed by implanting the scaffold on wounds in Wistar albino rats. The results demonstrated that MO-TES-PAMAM-G3-collagen scaffold showed superior skin regeneration properties than other scaffolds. The skin regenerative efficiency of MO NPs followed the order ZnO > TiO2 > CeO2 > SiO2 > Fe3O4 NPs. This result can be attributed to higher mechanical strength, cell viability, and better antibacterial activity of ZnO-TES-PAMAM-G3-collagen scaffold that leads to accelerate the skin regenerative properties in comparison to other metal oxide based collagen scaffolds.

Leather industry has been undergoing a paradigm shift from chemical to enzyme-based processes for removal of hair and opening up of fibers from skin prior to its conversion into leather. This involves the use of protease for hair removal and amylase for opening the fibers in the place of sodium sulfide and calcium hydroxide, respectively. The enzymes are currently applied through various methods such as the use of salt, kaolin, and sawdust. Additionally, the robustness of the enzymatic approach under various environmental conditions needs to be ensured to enhance its popularity. With a view to this, the possibility of utilizing enzyme immobilized on zinc oxide nanoparticles was explored. Enzyme immobilized nanoparticles (nano-biocatalyst) at a concentration of 1.0% was optimized for hair removal, and compared to conventional sodium sulfide method. The decrease in the time required for matching efficiencies has been observed with the use of nano-biocatalyst. Histopathology results confirmed that there is no distortion of fibers with the usage of nano-biocatalyst. The study demonstrates the potential use of enzyme immobilized nanoparticles in leather processing and could ideally turn out to be a sustainable approach on account of reduction in emission loads from the process.

Functionalization of nanoparticle with specific groups is one of the most straightforward strategies to induce structural stability and specific cell responses from collagen based biomaterials. The effect of functionalised nanoparticles on triple helical conformational changes in collagen has not been understood well. For understanding the role of functionalization on collagen conformation, gold nanoparticles (Au NPs) prepared through wet chemical methods and functionalized with organic molecules (F-AuNPs) such as self-assembled monolayer (SAM), (3-aminopropyl) triethoxysilane (APTES), Polysaccharides (pectin and chitosan) and Poly(amido amine) PAMAM dendrimer (G0), were characterised and their interaction with collagen was studied. Protein conformational changes assessed by circular dichroism spectroscopy (CD) reveals that triple helical conformation of collagen was retained in presence of functionalized gold nanoparticle. The biocompatibility of functionalized gold nanoparticle was analysed against keratinocytes (HaCaT) cell by using (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) MTT assay. The result suggested that dendrimer functionalized gold nanoparticle exhibited higher cell viability when compared to other molecules functionalized gold nanoparticles studied. Based on the outcome of this study it can be envisioned that dendrimer functionalized gold nanoparticle mediated collagen materials are highly suitable for tissue engineering and cosmetic application.

Driven by the environmental benefits that bio-bleaching could bring, the interest in xylanase has received enormous attention and hence, the search of xylanase with properties like no cellulase activity, function at elevated temperatures and pH continues. The present study reports the production of extracellular xylanase from Aspergillus nidulans using waste agro-residues as substrate. The optimum temperature (60 °C) and pH (9.0), classified the xylanase as thermo and alkali tolerant. The addition of salt of Mn2+ increased the xylanase activity to almost double; however, these ions were unable to protect the enzyme from thermal inactivation. The FTIR spectra of bamboo pulp treated with this xylanase, revealed reduction in lignin as evident from reduced peak intensity coupled with the reduction in kappa number. The SEM image of enzyme treated pulp, exhibited dissociation in fibers exposing the internal structure with slight roughness. Swelling was also observed there by increasing its thickness which eventually helped in improving its physical properties. The bleaching efficacy of indigenous xylanase as indicated in this study, has established its competence as a promising candidate for pre-treating the bamboo pulp.

The leftover vegetable oils after frying of food at higher temperature is toxic to environment as diminutive of technologies for proper disposal and reuse of waste cooking oil. An highly water soluble and emulsifier-free phosphorylated fatliquor with the emulsion stability of more than 60 minutes from economically cheap deep fried oils on transesterification with highly biodegradable ecologically innocuous and water soluble Poly (ethylene glycol) with p-Toluene Sulphonic acid followed by phosphorylation produces highly water dispersible and stable material for leather applications. The synthesised phosphorylated fatliquors were ascertained for the lubrication of collagen fibres and fibre splitting of goat skin by SEM analysis. The transesterification has confirmed by FT-IR, fat composition oils, COD, BOD, total solid in spent liquor were analysed. Physical characteristics of leathers were analysed by tensile strength, tear strength, elongation and quality assessments by hand evaluation by experts. Acid, iodine, saponification values, particle size of phosphorylated fatliquors, surface wettability, thermal stability of leathers were analysed and the properties compared. The finding can assist an emulsifier-free lubricating process significantly as currently available leather chemicals.

Nanopigment based coatings have attracted considerable interest due to their high surface area, enhanced covering strength, resistance to scratch and abrasion properties. The preparation of nano pigments from industrial waste is challenging and can potentially be used in various industrial applications. As per environmental concerns, utilization of insoluble residues such as black liquor separated from paper and pulp industry waste as value added products is essential for industrial waste management. Tailoring of nanosized pigment colorants with improved surface covering properties from the industrial waste black liquor has been proposed. The acidified and precipitated insoluble organic part of black liquor was used for pigment preparation. Surface modification of pigment with silica coating, through sol-gel method, using synthesized Gemini surfactant, was adopted for size reduction. The prepared nanopigments were characterised through Fourier Transform Infrared Spectroscopy (FT-IR), Reflectance measurement and Transmission Electron Microscope (TEM). The results for optical studies of the prepared pigment confirms the suitability of this surface modified pigment as a brown coloring agent. From the DLS measurements, the dispersion property of prepared pigment was found to be monodispersed with a narrow size distribution of approximately 50–200 nm. The industrial applicability of such nano pigment was analysed by utilizing it as colorant for the leather surface coating as well as in plastics. Commercial viability of nano-pigments as coloring agents, adds value to the paper and pulp industry waste in a sustainable way.

$$\hbox {Yb}^{3+}$$ - $$\hbox {Er}^{3+ }$$ codoped lanthanum upconverting nanostructures with varying concentration of dopants have been synthesized by catechin method. The prepared upconverting nanostructures were characterized through XRD, TEM, XPS, NIR absorption, TGA and DSC analysis. TEM study confirms the formation of square-shaped nanoplates with size less than 100 nm. XPS peaks around 830–854 eV further reveal the formation of $$\hbox {LaF}_{3}$$ in the prepared samples. Frequency upconversion spectra from the developed nanostructures corresponding to the $$^{2}$$ H $$_{11/2}$$ , $$^{4}\hbox {S}_{3/2}\rightarrow {}^{4}\hbox {I}_{15/2}$$ and $$^{4}\hbox {F}_{9/2}\rightarrow {}^{4}\hbox {I}_{15/2}$$ transitions upon 980 nm excitation are reported. Enhancement in the upconversion emission of catechin-based lanthanum nanostructures has been observed when compared with that prepared by ammonium di-n-octadecyldithiophosphate (AODTP) method. Synopsis. Enhancement of upconversion luminescence is observed in square-shaped nanoplates of La nanostructures using catechin as a chelating ligand.

Rare earth orthovanadates and phosphates offer a very high opportunity for fabrication of nanoscale devices that exploit their luminescence properties. Optimization of luminescence by way of modulation of size, shape, structure, and morphology has been an area of study for several researchers. There has been a debate as to whether doped orthophosphate or orthovanadate is better luminescent material as both are chemically similar. It has been reported earlier that catechin hydrate can play the role of a structure director and thus influence the luminescence properties of orthovanadates. In this work, a catechin modulated the synthesis of Eu-doped lanthanum orthophosphate by phosphate substitution into vanadate host lattice is reported. A mechanistic understanding of the luminescence changes in LaMO4 has been proposed. During the substitution of V with P, catechin modulates the structure between 1D nanorods and nanowires. The host crystal structure, shape, and size influence the luminescence properties in doped LaMO4.

A series of Yb3+–Er3+ codoped LaVO4 phosphors using catechin as a chelating agent and phase director have been prepared by the low temperature hydrothermal synthesis technique. The sample exists in two different crystalline phases, i.e., monoclinic and tetragonal, depending on the concentration of dopants. Structural, optical, and thermal characterizations have been done by using X-ray diffraction, EDX, FE-SEM, UV–vis diffuse reflectance, FTIR, and TGA analysis. Upconversion emission (UC) based imaging and drug delivery systems have been proposed to overcome some significant drawbacks of existing systems. Though fluorides are better hosts for UC, their harmful character has forced researchers to look at alternatives including oxides. The frequency upconversion emission (UC) study upon excitation at 980 nm has been performed in this particular host (m-LaVO4) which is not an ideal upconverting host. The sample emits bright green color upconversion emission, along with relatively weak emissions in the blue, ...

This work presents the design and study of pectin (PEC) reinforced Egg Lecithin (EPC) liposomes and their structural, mechanical and thermal properties at fluid/solid interface. The liposomes have been analyzed using ATR-FTIR, DSC, SAXS and Quartz crystal microbalance (QCM) with dissipation. An asymmetric melting temperature profile in DSC thermograms with increasing concentration of PEC suggested reduced co-operativity of lipids in the vesicles resulting from different populations of PEC associated lipids. QCM showed PEC stabilized EPC liposome has nearly an order higher mechanical strength compared with EPC as also seen from enhanced heat capacity in DSC. SAXS shows that the PEC locating in the lipid bilayer results in swelling in the non-polar region (~30%) and a reduction in overall bilayer thickness (~6%) compared with that of pure EPC. The nearly equal rotation correlation time τr for EPC (3.25 ± 0.18 ns) and PEC stabilized liposomes (3.20 ± 0.2 ns) from fluorescence spectroscopy suggests that PEC in lipid bilayers does not induce any structural deformations. These liposomes visualized by transmission electron microscopy and atomic force microscopy show well-defined morphology. The findings offer a new perspective on understanding the interactions between lipid molecules and biopolymers and may aid in designing stable composite delivery vehicles.

There are reports that co-immobilization of enzymes on solid supports can circumvent the problem of loss of enzyme activity in a soup of enzymes. To understand the mechanistic pattern by which solid support can ensure enzyme stability. Copper oxide nanoparticles (CuO Nps) were employed to immobilize protease and amylase. These are enzymes widely used together and at different stages in various industrial activities such as laundry, leather processing, etc., the immobilization of enzymes was confirmed through FTIR, TGA, and zeta potential analysis. Enzyme activity assays were carried out to understand enzyme activity with and without immobilization. The interaction between the nanoparticle surface and enzyme was studied through molecular docking studies. Thus, the study provides an insight into how the immobilization of enzymes on nanoparticles could be beneficial for industrial applications.

One of the prerequisites for making leather is to remove the inter-fibrillar proteins and noncollagenous materials, such as hair, flesh, etc. These proteinous and nonproteinous materials are removed in several steps, cumulatively known as the pretanning (or beam house) operations. A paradigm shift from chemical- to enzyme-based processes ensured that these noncollagenous materials were removed using enzymatic digestion rather than brutal osmotic forces employing chemicals like lime and sulfide. In order to make sure that a cocktail of enzymes (protease + amylase) have broad application and stability, their immobilization onto matrices that can enable overcoming such drawbacks is essential. This work, taking clues from the catalytic applications of nanoparticle-immobilized enzymes looks at metal oxide nanoparticle-immobilized enzymes for unhairing and fiber opening applications in a facile manner. Iron oxide (Fe3O4) nanoparticles have been selected for the present study since metal oxides are proven as an ...

Complex coacervation of two naturally occurring polymers is crucial in design of wall materials, particularly in the food and related industry. This work presents an analysis of the complex coacervate yield of two oppositely charged polymers, viz., gelatin and wattle varying parameters like pH, polymeric mass ratio, and total biopolymer concentration through zeta potential and turbidity measurements. Results show that for the boundary conditions employed in the study, maximum coacervate yield (65 ± 0.9 %) was for wattle:gelatin ratio of 2:1, pH 4.2. At 2.2 ± 0.1 g of wattle/ g of gelatin, large micron-sized aggregates with polydispersity index of 1 have been obtained. Turbidity of the dispersion is inversely proportional to coacervate yield and has been optimized at a total biopolymer concentration of 3% at a wattle to gelatin mass ratio of 2 for applications.

In the past few decades, the design and fabrication of bio-scaffolds exhibiting structural stability in long-term and biocompatibility has received much attention in the field of tissue engineering application. In this direction, we have synthesized different mole ratio of PdO–TiO2 nanocomposites (1:1, 2:1 and 3:1 of Pd:Ti, size 5–11nm, 7–16 nm and 9–22 nm) through a simple single step sol–gel method. The obtained nanocomposites of different sizes were assimilated into poly (methyl methacrylate) grafted collagen biopolymer (g-PMMA-Collagen), resulting in a PdO–TiO2-g-PMMA-Collagen based scaffold. Physico-chemical properties and biocompatibility of g-PMMA-Collagen/PdO–TiO2-g-PMMA-Collagen scaffolds were analysed by using various techniques such as XRD, FT-IR, TGA, DSC, Universal Testing Machine, MTT, Alkaline phosphatase, Alizarin Red S staining assay and the obtained results were compared against pure collagen scaffold. Our results suggest that the incorporation of 1:1 mol ratio PdO–TiO2 nanocomposite (Size, 5–11 nm) offers a higher thermal stability (83.45 °C) and mechanical strength (Young's modulus 105.57 MPa) than the pure collagen scaffold (71.64 °C, 11.67 MPa). The PdO–TiO2 endowed scaffolds were not toxic to MG 63 cells (human osteosarcoma) and enhanced the ALP activity on the scaffolds during in vitro osteogenic differentiation. This work provides a new approach for mechanical reinforcing and enhanced osteogenic activity of collagen scaffolds without affecting its conformation or biocompatibility, an aspect that possibly makes them ideal for bone tissue engineering applications.

During leather processing, most of the trimmed raw skins/hides are thrown as wastes which require solid waste management. In the present study, raw hide trimming wastes have been used as the source for extracting elastin. Elastin is extracted from raw trimming wastes through thermo-chemical treatment method using alkali pre-treatments. The physical characterization using differential scanning calorimetry showed the melting point at 104 °C. Elastin has shown higher denaturation temperature above 275 °C and thermal gravimetric shows six mass loss steps. Through thermo-chemical extraction method, 90% of yield has obtained. From various characterization results, it is observed that extracted elastin is chemically confined with its physicochemical properties. Moreover, biocompatibility studies also confirm that the enhancement of cell proliferations in the presence of elastin, which makes it more non-toxic and biocompatible which makes it feasible for tissue engineering applications. The study provides an insight into tapping unused high-value products from tannery wastes.

The structural and optical properties of Yb3+/Er3+/Eu3+ co-doped LaVO4 nanoparticles have been investigated by XRD, FT-IR, HRSEM, DRS and fluorescence analysis. The crystal structure of all the synthesized samples showed the existence of tetragonal LaVO4. Influence of Eu3+ ions co-doping in Yb3+- Er3+: LaVO4 nanoparticles are systemically studied for both upconversion luminescence and emission studies. The energy transfer mechanism involved in LaVO4 phosphors is presented in detail based on their absorption, upconversion emission and pump power dependence study. The green to red fluorescence intensity ratio and asymmetry ratio are calculated with the variation of Eu3+ ion concentration. The upconversion fluorescence intensity ratio increases with the increase of pump power density which attributes the application of present phosphors as temperature sensors. Color purity of Yb3+/Er3+/Eu3+ co-doped LaVO4 nanophosphors hardly shows any change with variations in pump power. Dual mode luminescence of these nanophosphors finds its applications in anti-counterfeiting inks.

The present work describes the preparation of leather dye using paper and pulp industry wastes. In this work, black liquor was modified to pH 7 by using sulfuric acid and was used as a retanning agent for leather processing. The characteristic features of modified products were thoroughly investigated by Fourier transform infrared spectroscopy (FT-IR), Zetasizer, and energy dispersive spectrometer (EDS). The purity of the modified black liquor is ascertained through UV-visible spectroscopy. The modified black liquor treated leather shows good softness, filling, and high strength, with uniform dyeing. This process divulges to increase the accessibility to value-added products using black liquor as a starting material. This study paves a way in providing some basic understanding on the degradation of paper and pulp industry waste and its chemical constituents like phenolic hydroxyl groups involved in leather dyeing cum retanning effect. Additionally, this research works emphasis on the reduction of conventional synthetic chemicals used in leather manufacture by utilizing the waste product leads to reduce the environmental pollution loads.

In the past few decades, the design and fabrication of bio-scaffolds exhibiting structural stability in long-term and biocompatibility has received much attention in the field of tissue engineering application. In this direction, we have synthesized different mole ratio of PdO-TiO

By-product utilisation has been recognised as a promising cleaner technology has attracted intense attention from both academic and industrial fields in the last decade. Industrial society is currently experiencing constraints imposed by our resource system by improving existing processes or finding newer way of waste utilisation. Waste and by-product streams from existing industrial sector (e.g. paper and pulp industry, meat industry) could be used as renewable resources for production of useful artefacts. This article mainly features recent research progress towards the utilisation of by-product in leather processing. This study was carried out to evaluate the propriety of using by-product black liquor from paper and pulp industry as filler in leather processing. Chemical modification of the black liquor has been performed to sustain a good compatible between the chemicals and also to improve the diffusion of black liquor into the leather substrate. The modification of black liquor was done by means of pH adjustment. Effect of filling nature of black liquor on strength property, softness nature, related morphological changes, and the dyeing property of the leather samples were thoroughly investigated. The results reveal that chemical composition of black liquor modulated by the pH adjustment was found to have a strong influence on the overall performance of the leather substrate.

Potential applications of rare earth orthovanadates are increasing day-by-day owing to the possibilities of tuning the optical properties through a host of facile modifications. This has brought about the need to look at orthovanadates beyond those of Y, Gd and Lu. Amongst the possibilities, synthesis of LaVO4, with or without doping in its metastable zircon phase against the monoclinic phase which is a poor phosphor candidate has been challenging. With applications spreading to the areas of biology and medicine, a need to replace the conventional EDTA as a ligand strategy has been indicated by researchers in this area. Optimization of luminescent properties of t-LaVO4 for a range of applications would require fair control over not just the phase but also the size and shape as well. In this work, we report the use of catechin – a natural polyphenol as a structure director, wherein through modulation of the RE to catechin ratio, the phase as well as shape is controllable. The enhancement of luminescence upon doping with Eu3+ and Sm3+ is also found, indicating that the optical properties of these phosphors are strongly dependent on the morphology. The rod-like structure exhibited the strongest red emission with highest intensity. This procedure is simple and promises to provide a pathway for varying morphology into other lanthanide orthovanadates.

In recent years, blending various protein wastes has resulted in the development of new hybrid composites, which display innovative functionalities with superior physico-chemical properties. One of the options explored in this work is the suitable modification of collagen hydrolysate (waste from the leather industry) along with degraded black liquor from the paper and pulp industry. In detail, the preparation of hybrid composites from collagen hydrolysates and degraded black liquor of different pH (14 and 7) was performed through a simple process. The characteristic features of the composites were thoroughly investigated by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) using a Malvern Zetasizer and scanning electron microscopy (SEM). The multifunctionality of the hybrid composites provided the opportunity to utilize this type of composite as a retanning agent in leather processing. The composites also exhibited enhanced functional properties as well as improved dyeing, thus making them a better retanning agent. The composite treated leather shows good softness, improved belly filling, and high strength with uniform dyeing. Hence, the potential use of multifunctional hybrid composites has gained more importance in economic processing.

The current practising method for the lubrication of leather uses emulsions of oils in water (fatliquors) that are prepared using emulsifiers. In particular, the fatliquoring process is a sum of three processes – surface wetting, oil emulsion spreading and coating of oil on the fibre bundles. This method suffers from drawbacks on account of high water consumption for oil diffusion and discharge of wastewater carrying emulsifiers. This paper reports a new approach of preparing emulsifier-free ready-to use oil–solvent dispersions, and their tuning to obtain required softness in leather. The oil and the solvent, both determine the size of the dispersions. The addition of non-aqueous solvent tunes the size of the dispersions, as seen for an e.g. in the case of castor oil in heptane (Hep) and ethyl acetate (EA) mixture at a volume ratio of 0.9 : 0.1, wherein, size is 4 nm as against 3060 nm in 0.1 : 0.9 mixtures. The kinematic viscosity (ν) of oil–solvent dispersions was comparable with that of commercial fatliquors. In all cases, the surface tension of oil progressively decreases up to a certain concentration and thereafter, remains almost invariant. This is suggestive of formation of aggregates of solvents. An interesting correlation between the size and lubrication performance was observed. Such of those dispersions with appropriate diameter (10 < size < 300 nm) and polydispersity index < 0.3 had a good diffusion, leading to softer leathers. It is to be noted that to form oil in water emulsions with size in this range, a very large amount of emulsifiers/surfactants, which is invariably equal to or more than that of weight of oil is required. Surface energy of leathers was significantly altered depending on type of oil dispersions, thus in turn influencing the dispersion-leather contact and hence oil spreading on leather surface.

In this work, ZnO nanorods and Graphene-ZnO-PdO nanocomposite was synthesized through hydrothermal method. Crystallinity of the materials has been studied using X-ray diffraction (XRD) and morphology was analysed through Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission electron microscopy (TEM) techniques. The synthesized nanomaterials are used for the photocatalytic degradation of Methylene Blue (MB) under UV-light illumination (365 nm) and the results were compared with commercial ZnO material. Graphene-ZnO-PdO nanocomposite exhibits higher degradation of MB under UV-light illumination than ZnO nanorods and commercial ZnO material. These nanocomposite materials can so be used for methylene blue MB photodegradation as for textile wastewater treatment.

Mo-doped Gd1Ce1–xO3.5+Y (where x ranged from 0 to 0.3) oxides were synthesized as inorganic yellow pigments, which are benign and sustainable. The pigments exhibited good yellow color, with the yellowness value using the CIELAB 1976 system being around 39. In comparison to the existing reports on benign yellow pigments, which have been synthesized using high temperature calcination routes, this pigment has been synthesized through a low temperature sol–gel calcination route. The process also provided for a higher degree of size and shape control, leading to a bandgap of 2.82–2.52 eV. Size reduction to the nano level through the process provided a bottom up approach, where the presence of mineralizers enabled higher mass tone (b* value of around 80) at lower covering thickness. NIR solar reflectance, a measure of the ability of the pigment to contribute to energy savings by reflecting heat generating radiations of sunlight, was as high as 91%. The absence of toxic metal ions coupled with excellent chemical...

Gold nanoparticles have gained much attention due to their widespread biological and technological applications, and consequently their simpler synthesis via green chemistry has also become of foremost importance. We report the room temperature synthesis of spherical gold nanoparticles using curcumin alone as the reducing and stabilizing agent. The pH is found to have an important role in curcumin solubilisation and subsequent formation of curcumin conjugated gold nanoparticles (cAuNPs). UV-visible studies show that the cAuNPs formed are of uniform size and HRTEM studies confirm spheres of average size 18 nm. The DLS measurements show a particle size of 58 nm. The crystallinity has been determined by HRTEM and XRD. The conjugation of stable curcumin on the cAuNPs is indicated by FTIR spectra which also suggest that the phenolic and enolic groups of curcumin bring about the reduction. The zeta potential value of cAuNPs is −23 mV which is stable for up to 6 months at room temperature. The mechanism of cAuNP formation is inferred to be through temporal evolution. This is the first demonstration where curcumin is solubilized at alkaline pH without using any external agent and is used for reducing HAuCl4 to form cAuNPs. The non toxic nature of the cAuNPs is evidenced through biocompatibility studies using human blood cells.

Lanthanide orthovanadates of appropriate morphology, polymorph character and size are attractive for various electronic and magnetic applications. Though template free methods exist, there is a preference to facile template based methods for fine tuning of shape and size. The novelty of the methodology reported herein is the use of a biologically acceptable chelate such as catechin (5,7,3′,4′-tetrahydroxyflavan-3-ol for a selective synthesis of tetragonal LaVO4 over the preferred monoclinic phase) in a short duration of time. Optimal conditions ([cat4−]/[La3+] = 1/20; T = 210 °C for 4 h and pH 7) for the synthesis of t-LaVO4 (JCPDS no. 10-705226) with a crystal size of around 16 nm have been established. Our experiments on the role of pH in the formative steps of the complex indicated that catechin serves not only as a polymorph controller but it also aids in shape selection. Under optimal synthesis conditions, a switch over from isotropic to anisotropic structure was brought about by a pH change from 5 to 7. The process methodology has been tuned to ensure that the drawbacks associated with template based methods, viz., the presence of template impurities, have been significantly overcome. From CHN analysis and FTIR measurements, less than 2% carbon from catechin is found to coat the nanoparticle surfaces, which contributed to prevention of aggregation. Extending the work further, Gd3+ doped t-LaVO4 was also synthesized to obtain luminescent and magnetic properties (fluorescence lifetime of 0.2 ms and magnetization of 0.79 emu g−1 at RT), which are possibly ideal for imaging applications, such as for T1 contrast agents for MRI.

New cerium-based ceramic pigments, displaying Ce2Pr0.2FexO4.3+y stoichiometry, were obtained at low temperature using a sol–gel method. The powder precursor dissolved in 80% ethylene glycol was precipitated using ammonia and the obtained gel calcined at 800°C for 2 h to yield homogeneous and crystalline particles with a diameter of around 150 nm. The oxide was composed of cerium in its +4 oxidation state and Pr in its +3 oxidation state. The oxides with varying Fe content had an intense red-brown colour, with bandgap energy of around 2.2 eV at 0.1 mol% Fe doping. The near infra red reflectance from these pigments, a measure of their ability to reflect rather than absorb heat waves from sunlight was found to be 82.7%, even in the absence of a white reflective base. Such high near infra red reflectance from these pigments qualify them for being ideal cool pigments for surface coating applications.

Carbon-based nanomaterials (CBNs) such as graphene oxide (GO, planar shape-2D), reduced graphene (rGR, planar shape-2D), carbon nanotube (CNT, tubular shape -1D) and fullerene (C60, sphere shape-0D) can offer higher mechanical strength and biocompatibility to scaffold employed in wound healing applications. It is important to understand the role of dimensional aspects of CBNs on the scaffold properties. To contribute to this understanding, this paper reports the effect of dimensional aspects of Triethoxysilane poly (amidoamine) dendrimer generation 3 (TES-PAMAM-G3 or G3) functionalized carbon nanomaterials were introduced in the self-assembly processes of collagen. The prepared CBNs-TES-PAMAM-G3 -collagen scaffolds were characterized through various spectroscopic techniques and used in-vivo wound healing application. Among the CBNs-TES-PAMAM-G3 -collagen scaffolds investigated, a CNT-TES-PAMAM-G3-collagen scaffold showed enhanced mechanical properties (46 times compared to pure collagen), better cell viability and accelerate wound healing process than other scaffolds. Such enhanced mechanical properties for CNT-TES-PAMAM-G3-collagen scaffold can be attributed to the inherent strength and possibilities of alignment of the nanostructure along the linear axis of the collagen through the use of 1D nanotube. These results suggested that the CNT-TES-PAMAM-G3-collagen scaffolds are promising materials for tissue engineering and wound healing application.

Elastic compliance of DMPC liposomes with Hofmeister electrolytes: NaCl, Na2SO4, Na2CO3, NaNO3, KCl and MgCl2 studied using Quartz crystal microbalance with dissipation has been correlated with changes in their lamellar spacing from SAXS. The study suggests that hydration water of the different ions has an effect on the overall packing of the lipid bilayer that results as either a dehydrated liposome or where water smears the surface of the liposomes. Ratio of hydrogen bonded carbonyl and phosphate of polar region of the liposomes from ATR-FTIR spectroscopy, suggests that the polar groups are less hydrated due to the displacement of water by the electrolytes compared to pure DMPC and ordered in the sequence for cations as: K+

Collagen, an important fibrous protein and its stability is closely related to organizational order. In this work, organization of collagen in the presence of diphenyl phosphoryl azide (DPPA) was studied using circular dichroic spectroscopy, stress-strain characteristics and fibrillogenesis. The reconstituted collagen fibrils in the presence of DPPA were characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction and polarizing light microscopy. CD spectra show that the secondary structure of the collagen molecule is preserved when the concentrations of DPPA is less than 0.018 μM. The Increase in shearing stress with shearing speed is 5-8% higher in the presence of DPPA may be due to the rigidity of the collagen chains. DPPA facilitates self assembly processes, thinner fibrils are seen in polarizing light microscopy and seem to favor the molecular and phase structure of collagen. Thermal stability of collagen in the presence of DPPA ensured the integrity and stabilization of reconstituted collagen fibrillar matrices. Collagen fibrils have higher denaturation enthalpy 15 J/gm at 0.5 μM (DPPA) when compared to 10.5 J/gm for native collagen fibrils which is an indication of more stable fibrils. As a result, the reconstituted collagen fibrils in the presence of DPPA brought about the stabilization of the secondary structure of collagen molecules at lower concentrations of DPPA.

Stabilization of collagen for various applications employs chemicals such as aldehydes, metal ions, polyphenols, etc. Stability against enzymatic, thermal and mechanical degradation is required for a range of biomedical applications. The premise of this research is to explore the use of nanoparticles with suitable functionalization/encapsulation to crosslink with collagen, such that the three dimensional architecture had the desired stability. Collagen solution prepared as per standard protocols is treated with chromium(III) oxide nanoparticules encapsulated within a polymeric matrix (polystyrene-block-polyacrylic acid copolymer). Selectivity towards encapsulation was ensured by the reaction in dimethyl sulfoxide, where the PS groups popped out and encapsulated the Cr(2)O(3). Subsequently when immersed in aqueous solution, PAA units popped up to react with functional groups of collagen. The interaction with collagen was monitored through techniques such as CD, FTIR, viscosity measurements, stress analysis. CD studies and FTIR showed no degradation of collagen. Thermal stability was enhanced upon interaction of nanostructures with collagen. Self-assembly of collagen was delayed but not inhibited, indicating a compete binding of the metal oxide encapsulated polymer to collagen. Metal oxide nanoparticles encapsulated within a polymeric matrix could provide thermal and mechanical stability to collagen. The formed fibrils of collagen could serve as ideal material for various smart applications such as slow/sustained drug release. The study is also relevant to the leather industry in that the nanostructures can diffuse through the highly networked collagen fibre bundles in skin matrix easily, thus overcoming the rate limiting step of diffusion.

Increasing energy cost calls for exterior coatings with high near infra-red reflectance, so as to reduce heat absorption and in turn cost of air-conditioning. While modulations of substrate, use of white metal oxides as pigments or under-layers has been reported in past, reports on metal oxide or doped metal oxide pigments with high NIR reflectance is scarce. We report for the first time a blue colored cobalt aluminate type pigment prepared through doping of cerium, praseodymium or neodymium. CIELAB color measurements and calculation of E indicated that the Nd doped sample had crystal size of (36±1) nm, bandgap value of (2.4±0.2) eV and color coordinates similar to that of cobalt aluminate. The molar ratio as estimated by EDX was found to be Al : Cu : Co : Ce : Nd : O= 2 : 0.06 : 0.06 : 0.012 : 0.000 12 : 6.18. The pigment was found to have potential applications as a cool blue colorant, owing to changes in optical properties arising out of crystal chemistry changes. Incorporation of rare earth metal ions was found to enhance the NIR reflectance by 10%, when compared to a conventional cobalt aluminate pigment. The oxide has been well characterized and its performance as a pigment evaluated. We have proposed that changes in crystal lattice when neodymium enters into Ce 4+ sites enhance the NIR reflectance by about 9% as against the entry of

Nanoparticle mediated extracellular matrix may offer new and improved biomaterial to wound healing and tissue engineering applications. However, influence of nanoparticle size in extracellular matrix is still unclear. In this work, we synthesized different size of silver nanoparticles (AgNPs) comprising of 10nm, 35nm and 55nm using nutraceuticals (pectin) as reducing as well as stabilization agents through microwave irradiation method. Synthesized Ag-pectin nanoparticles were assimilated in the self-assemble process of collagen leading to fabricated collagen-Ag-pectin nanoparticle based scaffolds. Physico-chemical properties and biocompatibility of scaffolds were analyzed through FT-IR, SEM, DSC, mechanical strength analyzer, antibacterial activity and MTT assay. Our results suggested that 10nm sized Ag-pectin nanoparticles significantly increased the denaturation temperature (57.83°C) and mechanical strength (0.045MPa) in comparison with native collagen (50.29°C and 0.011MPa). The in vitro biocompatibility assay reveals that, collagen-Ag-pectin nanoparticle based scaffold provided higher antibacterial activity against to Gram positive and Gram negative as well as enhanced cell viability toward keratinocytes. This work opens up a possibility of employing the pectin caged silver nanoparticles to develop collagen-based nanoconstructs for biomedical applications.

Pigments with properties such as weather stability, thermal resistance and having functional properties such as NIR reflectance are desirable. In this, the inorganic pigments serve better than the organic pigments. However, the release of metal ions such as Pb and Co on exposure to the environment is raising alarms. One of the approaches considered ideal is to use naturally occurring oxides or their synthetic analogs as pigments after suitable modifications. One such classic example is that of chromium(III) oxide. We report a predominant solid state route, wherein a chromium–urea complex prepared under solvent free conditions was calcined at high temperature to obtain chromium(III) oxide nanoparticles. Introducing rare earth metal ions such as La and Pr, which have in recent years been reported to be environmentally benign and available in sufficient quantities resulted in nano-oxides with enhanced near-infrared reflectance, thus qualifying them as cool colorants.

Haematite nanoparticles have been synthesised on polyethylene glycol (PEG) template, through a two-step method consisting of oriented attachment followed by growth. The process involves the binding of Fe2+ centres to PEG, followed by a high temperature calcination reaction. During the calcination process, the template is sacrificed and Fe2+ is converted to α-Fe2O3. Infrared spectroscopy and thermogravimetric analysis indicate that the template leaves behind a carbonaceous residue over the haematite surface, which prevents further aggregation of the nanoparticles even after the removal of the template. PEG helps in connecting the crystal flocs through a bridging mechanism. The residual magnetic moment, particle size, shape and ionic strength of the synthesised haematite nanoparticles promote the formation of necklace-shaped structures. Directional growth of haematite nanoparticles brought about by PEG results in an increase in coercivity and near-zero remnant magnetisation at zero field strength. The magne...

Cationic chitosan can form polyionic complexes with anionic polysaccharides such as pectin, which can be cast into films in a similar manner to that of chitosan–starch blends. We report the use of such films as templates in the synthesis of hematite nanoparticles. Mechanistically, the interaction of the iron(II) centers with the carboxyl, amino and other functional groups in the film, after their adsorption into the pores of the template is the key to subsequent synthesis of nanoparticles through calcination. The spatial separation that the specificity of interaction provides is amply made use of through controlled calcination resulting in monodisperse nanoparticles of hematite nanoparticles. This paper also highlights the specific advantages such as rhombohedral shape, ∼40 nm intensity average diameter, narrow size distribution and weak ferromagnetic properties of using the polyion films at pH 2 as templates over polysaccharides either alone or in combination in solution or as blends.

By complexation with starch, Co2+ ions have been preferentially bound to starch, resulting in clathrate cages. A controlled preparative methodology which involves initial drying at a temperature of 80–90 °C, removed a large number of water molecules to provide for a solid rigid network, in which the metal ions remained segregated. Subsequent calcination and sacrifice of the template resulted in monodispersed nanoparticles of around 20 nm. The nanoparticles were characterized by a coercivity value of 893 Oe, Mr value of 0.1128 emu/g and Ms value of 0.6353 emu/g. The nanoparticles also possessed above 80% reflectance in near infrared region, with potential applications as cool green-black pigment which had sufficient covering properties for surface coating applications.

Conventional synthesis of silver nanoparticles employs a reducing agent and a capping agent. Surfactants are effec-tive capping agents as they prevent the aggregation of nanoparticles during storage and use. However, the biocompatibility of several of the surfactants is questionable. In this report, the use of thiosalicylic acid as both reducing and capping agent is reported. Compared to conventional synthesis, this methodology requires higher temperature for synthesis, which then is expected to result in aggregates of larger size. The ability of three different synthesis methodologies – direct heating, photochemical and microwave dielectric treatment were evaluated and assessed on the basis of the size, size distribution and stability of the particles. Microwave irradiation was found to be most suitable for achieving particles with a hydrodynamic diameter of 10 nm. Our studies indicate that -COO- group is involved in the reduction of Ag+ and –SH group of TSA is involved in the capping of the nanoparticles.

Easier, less time consuming, green processes, which yield silver nanoparticles of uniform size, shape and morphology are of interest. Various methods for synthesis, such as conventional temperature assisted process, controlled reaction at elevated temperatures, and microwave assisted process have been evaluated for the kind of silver nanoparticles synthesized. Starch has been employed as a template and reducing agent. Electron microscopy, photon correlation spectroscopy and surface plasmon resonance have been employed to characterize the silver nanoparticles synthesized. Compared to conventional methods, microwave assisted synthesis was faster and provided particles with an average particle size of 12 nm. Further, the starch functions as template, preventing the aggregation of silver nanoparticles.