Natural Pigments Research Articles

Non-invasive spectroscopic analyses of M. E. Chevreul’s colour plates: shedding new light on 19th century colour theory representation

During the early 19th century, colour’s theories flourished. In this context, Michel-Eugène Chevreul (1786–1889) developed a three-dimensional hemispherical colour space, reproduced and used for several decades by manufacturers, scientists, artists, architects, gardeners and designers, among others, to easily identify and classify colours. Despite the major influence and variety of chromatic spaces created by M. E. Chevreul, they have been the subject of a few scientific studies until now. This study will provide new information on the evolution of the printing technique, the materiality and the visual appearance of six different colour circles printed in 1847, 1855, 1861 and 1864. A dedicated analytical methodology was implemented combining visible and near-infrared reflectance imaging, X-ray fluorescence, Raman, short-wave infrared fibre optic reflectance and mid-infrared Fourier transform spectroscopies. This material identification revealed the coexistence of newly synthetized inorganic pigments, such as lead chromate, Prussian blue or Emerald/Scheele green, with established organic and inorganic pigments, such as cochineal lake, vermilion or minium. This study revealed a temporal evolution of the printing technique that leads to an improved colour representation.

Quantitative tracing the sources and human risk assessment of complex soil pollution in an industrial park

Pollution in industrial parks has long been characterized by complex pollution sources and difficulties in identifying pollutant origins. This study focuses on a typical industrial park consisting of 11 factories (F1–F11) including organic pigment, inorganic pigment, and chemical factories in Hunan Province, China, here, a total of 327 sample points were surveyed. Eight pollutants (Mn, Cd, As, Co, NH3–N, l, 1,2-Trichloroethane, chlorobenzene, and petroleum hydrocarbons) were classified as contaminants of concern (COCs). This study assessed the contributions of driving factors to the distribution of COCs in the soil. Pollutant source apportionment was conducted using positive matrix factorization (PMF) and random forest (RF). The results revealed that the main factors driving pollution are groundwater migration, non-compliant emissions, leaks during production, and interactions among pollutants. The primary pollution sources were four chemical factories and an inorganic pigment factory. Source 5 demonstrates significant correlations with TCA (29.6%), CB (30%), and As (31.6%). Two chemical factories (F7 and F10) are the most significant pollution source with a risk assessment contribution rate of more than 60%. The present study sheds some light on the contamination characteristics, source apportionment and source-health risk assessment of COCs in industrial park. By utilizing the proposed research framework, decision-makers can effectively prioritize and address identified pollution sources.

Potent inhibition of human and rat 17β-hydroxysteroid dehydrogenase 1 by curcuminoids and the metabolites: 3D QSAR and in silico docking analysis

ABSTRACT Curcumin, an extensively utilized natural pigment in the food industry, has attracted considerable attention due to its potential therapeutic effects, such as anti-tumorigenic and anti-inflammatory activities. The enzyme 17β-Hydroxysteroid dehydrogenase 1 (17β-HSD1) holds a crucial position in oestradiol production and exhibits significant involvement in oestrogen-responsive breast cancers and endometriosis. This study investigated the inhibitory effects of curcuminoids, metabolites, and analogues on 17β-HSD1, a key enzyme in oestradiol synthesis. Screening 10 compounds, including demethoxycurcumin (IC50, 3.97 μM) and dihydrocurcumin (IC50, 5.84 μM), against human and rat 17β-HSD1 revealed varying inhibitory potencies. These compounds suppressed oestradiol secretion in human BeWo cells at ≥ 5–10 μM. 3D-Quantitative structure-activity relationship (3D-QSAR) and molecular docking analyses elucidated the interaction mechanisms. Docking studies and Gromacs simulations suggested competitive or mixed binding to the steroid or NADPH/steroid binding sites of 17β-HSD1. Predictive 3D-QSAR models highlighted the importance of hydrophobic regions and hydrogen bonding in inhibiting 17β-HSD1 activity. In conclusion, this study provides valuable insights into the inhibitory effects and mode of action of curcuminoids, metabolites, and analogues on 17β-HSD1, which may have implications in the field of hormone-related disorders.

Unlocking fungal quorum sensing: Oxylipins and yeast interactions enhance secondary metabolism in monascus

Exploring the symbiotic potential between fungal and yeast species, this study investigates the co-cultivation dynamics of Monascus, a prolific producer of pharmacologically relevant secondary metabolites, and Wickerhamomyce anomalous. The collaborative interaction between these microorganisms catalyzed a substantial elevation in the biosynthesis of secondary metabolites, prominently Monacolin K and natural pigments. Central to our discoveries was the identification and enhanced production of oxylipins (13S-hydroxyoctadecadienoic acid，13S-HODE), putative quorum-sensing molecules, within the co-culture environment. Augmentation with exogenous oxylipins not only boosted Monacolin K production by over half but also mirrored morphological adaptations in Monascus, affecting both spores and mycelial structures. This augmentation was paralleled by a significant upregulation in the transcriptional activity of genes integral to the Monacolin K biosynthetic pathway, as well as genes implicated in pigment and spore formation. Through elucidating the interconnected roles of quorum sensing, G-protein-coupled receptors, and the G-protein-mediate signaling pathway, this study provides a comprehensive view of the molecular underpinnings facilitating these metabolic enhancements. Collectively, our findings illuminate the profound influence of Wickerhamomyces anomalous co-culture on Monascus purpureus, advocating for oxylipins as a pivotal quorum-sensing mechanism driving the observed symbiotic benefits.

Naturally biocompatible melanin based iron-complex nanoparticles for pH-responsive magnetic resonance imaging

The sensitivity and diagnostic accuracy of magnetic resonance imaging mainly depend on the relaxation capacity of contrast agents (CAs) and their accumulated amount at the pathological region. Due to the better biocompatibility and high-spin capacity, Fe-complexes have been studied widely as an alternative to replace popular Gd-based CAs associated with potential biotoxicity. Compared with a variety of Fe complex-based CAs, such as small molecular, macrocyclic, multinuclear complexes, the form of nanoparticle exhibits outstanding longitudinal relaxation, but the clinical transformation was still limited by the inconspicuous difference of contrast between tumor and normal tissue. The enhanced effect of contrast is a positive relation as relaxation of CAs and their concentration in desired region. To specifically improve the amount of CAs accumulated in the tumor, pH-responsive polymer poly(2-ethyl-2-oxazoline) (PEOz) was modified on melanin, a ubiquitous natural pigment providing much active sites for chelating with Fe(III). The Fe(III)-Mel-PEOz we prepared could raise the tumor cell endocytosis efficiency via switching surface charge from anion to cation with the stimuli of the decreasing pH of tumor microenvironment. The change of pH has negligible effect on the r 1 of Fe(III)-Mel-PEOz, which is always maintained at around 1.0 mM−1s−1 at 0.5 T. Moreover, Fe(III)-Mel-PEOz exhibited low cytotoxicity, and satisfactory enhancement of positive contrast effect in vivo. The excellent biocompatibility and stable relaxation demonstrate the high potential of Fe(III)-Mel-PEOz in the diagnosis of tumor.

Ultrafast Spectroelectrochemistry of the Catechol/o‐Quinone Redox Couple in Aqueous Buffer Solution

AbstractEumelanin is a natural pigment found in many organisms that provides photoprotection from harmful UV radiation. As a redox‐active biopolymer, the structure of eumelanin is thought to contain different redox states of quinone, including catechol subunits. To further explore the excited state properties of eumelanin, we have investigated the catechol/o‐quinone redox couple by spectroelectrochemical means, in a pH 7.4 aqueous buffered solution, and using a boron doped diamond mesh electrode. At pH 7.4, the two proton, two electron oxidation of catechol is promoted, which facilitates continuous formation of the unstable o‐quinone product in solution. Ultrafast transient absorption (femtosecond to nanosecond) measurements of o‐quinone species involve initial formation of an excited singlet state followed by triplet state formation within 24 ps. In contrast, catechol in aqueous buffer leads to formation of the semiquinone radical Δt>500 ps. Our results demonstrate the rich photochemistry of the catechol/o‐quinone redox couple and provides further insight into the excited state processes of these key building blocks of eumelanin.

A starch-based 3D printed intelligent colorimetric film co-loaded natural pigments for visualizing food freshness: Effect of nozzle size on gel structure formation

Freshness intelligent visualization packaging is an innovative form for fresh/pre-made foods. Here, a highly responsive 3D printed intelligent colorimetric film (CF) was prepared by incorporating blueberry anthocyanin-phycocyanin (BA-PC) as an indicator and chondroitin sulfate (CS) as a co-pigment/co-carrier into a potato starch (PS) matrix. Enhanced sensitivity and stabilizing effect of CS on BA-PC were demonstrated to perform through sulfate group complexation and hydrogen bonding. CF was formed by modulating the 3D printed nozzle size from 0.2 mm to 0.6 mm, where CF 0.4 (nozzle diameter = 0.4 mm) presented the smoothest and homogeneous gel structure, with the highest sensitivity to ammonia response (35.43%) by the action of appropriate ink extrusion. Besides, CF 0.4 exhibited high antioxidant activity (DPPH and ABTS radical scavenging rates >75%), biosafety, and degradability. The film responded efficiently to the freshness of salmon and beef, and this colorimetric monitoring reflection was transferred to digitized freshness color signals by recognizing RGB values via a smartphone App, which reduced inter-individual differences in visual recognition. Overall, the findings broaden the diverse applications of 3D printing technology in the intelligent food packaging industry.

Evaluating Color Stability of Three Different Provisional Crown Materials: A Short Study

Purpose: To evaluate and compare the colour stability of three different provisional restorations using three different pigmented solutions Material and Methods: Total six samples of each material for each group ( Self-cure PMMA, Revotek LC, and CAD-CAM milled ) with the following specifications 2mm occlusal reduction, 1.5 axial reduction, 1mm round chamfer finish line, 6° convergence angle. This prepared tooth will be used as a guide for the metal die. After immersion in a staining solution of synthetic saliva (control), synthetic saliva and tea, synthetic saliva, and turmeric, on the 1st, 7th and 30th-day color measurement was done using a Spectrophotometer. Results: Mean values were compared using one-way analysis of variance (ANOVA) (statistically significant when P < 0.05). Post hoc test using Tukey’s honestly significant difference was employed to identify significant groups (statistically significant when P < 0.05). Repeated measures of ANOVA were performed to analyze the color stability of the different specimens at different periods of storage. Significant groups were identified using the Bonferroni test. Conclusion: Maximum discoloration was seen in synthetic saliva &turmeric solution for all the two materials. CAD-CAM is the best material out of both if the provisional restoration has to be given for a longer duration in the esthetic region.

Characterization, components, and chemical structure of a novel natural pigments derived from Streptomyces tauricus

Characterization, components, and chemical structure of a novel natural pigments derived from Streptomyces tauricus

Optimization of ultrasonic assisted ethanolic extraction for natural pigments from butterfly pea flower applied in Thai dessert using Box-Behnken approach

Butterfly pea is a natural color source used in food and dessert. This study optimized ultrasound-assisted extraction with ethanol for pigments from butterfly pea flowers (BPF) using a Box-Behnken method. Key factors explored were solid-to-solvent ratio, ultrasound extraction time, and ethanol concentration. The extracted compounds were evaluated for extraction yield (EY), total phenolic content (TPC), total anthocyanin content (TAC), and DPPH antioxidant activity. EY increased significantly with reduced ethanol concentration. Optimal conditions were predicted and experimentally validated. BPF extracts showed distinct absorption wavelengths at different pH levels. BPF extract was used in coconut milk jelly, resulting in the lowest b* value. These findings highlight the value of optimal ultrasonic-assisted extraction for enhancing BPF's natural colorant extraction and promoting sustainable use in food and dessert applications.

Extraction and characterization of carotenoid pigments with antioxidant and antibacterial potential from marine yeast Rhodotorula sp. KSB1.

Pigments are coloring agents used widely in different industrial sectors. There is a demand for using natural pigments rather than synthetic dyes because of the health hazards caused by synthetic dyes. Many natural pigments have different medicinal activities which can contribute to the nutritional value of the product. This study was carried forward with marine yeasts which can produce pigments. A total of 4 marine yeast isolates were recovered from the mangrove area of Sundarbans, West Bengal, India. Among them, the isolate KSB1 produced 856µg/g total concentration of carotenoid pigment and the dry mass weight was 3.56g/L. The stability of the extracted pigments was checked using temperature, pH, UV light exposure time, and different saline conditions. The pigments were characterized using HPLC and FTIR analysis. All of the extracted pigments showed good antioxidant activity in DPPH, metal chelating, and reducing power assay. The pigments were also found to have good antibacterial activity against the bacterial pathogens Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli. Carotenoid pigment from KSB1 was found to have maximum activity in all the pathogens. The cytogenotoxicity using onion roots and phytotoxicity analysis indicated that the pigments were non-toxic and safe for cells. Finally, the potential marine yeast was identified using 18s rRNA sequencing and identified as Rhodotorula sp. KSB1 (Accession no. MH782232).

Industrial mining trial for polymetallic nodules in the Clarion-Clipperton Zone indicates complex and variable disturbances of meiofaunal communities

Following several small-scale benthic disturbance experiments, an industrial polymetallic nodule collector trial was conducted by the company Global Sea mineral Resources (GSR) in their exploration contract area in the Clarion-Clipperton Zone using the pre-prototype vehicle Patania II (PATII). In this study, meiofaunal (i.e., nematode abundance, ASV diversity and genus composition) and environmental (i.e., grain size, total organic carbon/total nitrogen and pigment) properties are compared between disturbance categories (i.e., Pre-impact, Collector Impact and Plume Impact). One week after the trial, proxies for food availability within the Collector Impact sediments were altered with lower total organic carbon (TOC) and pigment (i.e., CPE: sum of Chlorophyll a and phaeopigments) values. Albeit not significant, the observed decrease of nematode abundance and ASV diversity, further indicate the consequences of the removal of the ecologically important surface sediment layer within the PATII tracks. Next to sediment removal, exposed sediments were modified in different ways (e.g., central strips, parallel caterpillar imprints with alternating bands of depressions/ripples and interface patches) and were also subject to heavy collector-induced sediment blanketing. We propose that these cumulative impacts have led to intricate seabed modifications with various levels of disturbance intensity which resulted in the high meiofaunal variability observed. Adjacent nodule-rich areas (i.e., Plume Impact) received considerable levels of sediment deposition (2-3 cm) and were defined by significantly lower food sources (CPE, TOC, carbon to nitrogen ratio) and an observation of meiofaunal enrichment (i.e., higher average nematode abundance and ASV diversity; although statistically non-significant), but mechanisms behind these ecological changes (e.g., suspended material-surface fluxes, passive dispersal of fauna in the plume vs. active upward migration and “viability” of redeposited fauna) remain unresolved. We conclude that complex benthic pressure-response relationships associated with the PATII trial, combined with the high degree of natural spatial and temporal variability in abyssal meiofaunal communities and sedimentary parameters, complicates the quantitative assessment of deep-sea mining associated disturbances.

Anthocyanins and the Antioxidant Capacities of Wild Berries that Grow in Shizuoka, Japan

ABSTRACT Fruits from five wild edible berries that grow in the eastern region of Shizuoka (Japan) were collected, and their antioxidant activities were evaluated using the ORAC, DPPH, FRAP, and ABTS assays to obtain basic scientific knowledge of these species. Among the Shizuoka wild berries tested, Rubus microphyllus L. fil. exhibited the highest antioxidant activity, which is equivalent to that of commercial raspberry (Rubus idaeus L.). Furthermore, anthocyanins from these wild berries were analyzed using quantitative 1H NMR spectroscopy. Cyanidin-3-glucoside and pelargonidin-3-glucoside were detected in Shizuoka wild berries, with the latter identified as the characteristic anthocyanin. The present study revealed that Shizuoka wild berries are rich in natural antioxidants and pigments and are therefore potentially beneficial for reducing the risks of associated with lifestyle-related diseases in consumers.

An Assessment of Marine Natural Pigments for Medicinal Potency

An Assessment of Marine Natural Pigments for Medicinal Potency

Organic Electronics in Flexible Devices: Engineering Strategy, Synthesis, And Application

In recent years, flexible electronics have made significant strides, especially in organic light-emitting diodes, photovoltaics, thin-film transistors, integrated circuits, sensors, and memories. This study investigates the pivotal role of organic electronics in shaping flexible and wearable technology. It explores key aspects such as conductive polymers, small molecule organic semiconductors, and the use of organic dyes and pigments in displays, alongside synthesis techniques like polymerization and vapor deposition. These methods highlight advances in flexibility engineering and integration into wearable devices, enabling innovations like textile-integrated electronics and ultra-thin, skin-like interfaces. The discussion also covers synthesis and fabrication strategies, emphasizing cost-effective, solution-processing techniques for manufacturing electrodes, interconnects, and metal contacts on various flexible substrates. Advanced materials like graphene polymer composites, carbon-nanotube composites, and polymer-ceramic composites are investigated for enhancing stretchability and flexibility in device architectures. Furthermore, the paper examines the evolution of flexible devices, focusing on design strategies for flexibility and stretchability, innovative engineering polymers, composites, and device architectures, including 3D integration. Integration techniques in wearable devices, such as textile integration and skin-like electronics, are discussed, showcasing their transformative potential in applications like health monitoring devices, smart clothing, and wearable displays. Finally, the paper proposed solutions to address challenges such as durability, stability, scalability, and manufacturing efficiency, emphasizing the ongoing quest for improved materials and manufacturing processes. The conclusion underscores the transformative potential of organic electronics, envisioning a new era of wearable and flexible technology seamlessly integrated into daily life, revolutionizing our interactions with electronic devices.

Multimodal non-invasive probing of stress-induced carotenogenesis in the cells of microalga Bracteacoccus aggregatus.

Microalgae are the richest source of natural carotenoids-accessory photosynthetic pigments used as natural antioxidants, safe colorants, and nutraceuticals. Microalga Bracteacoccus aggregatus IPPAS C-2045 responds to stresses, including high light, with carotenogenesis-gross accumulation of secondary carotenoids (the carotenoids structurally and energetically uncoupled from photosynthesis). Precise mechanisms of cytoplasmic transport and subcellular distribution of the secondary carotenoids under stress are still unknown. Using multimodal imaging combining micro-Raman imaging (MRI), fluorescent lifetime (τ) imaging (FLIM), and transmission electron microscopy (TEM), we monitored ultrastructural and biochemical rearrangements of B. aggregatus cells during the stress-induced carotenogenesis. MRI revealed a decline in the diversity of molecular surrounding of the carotenoids in the cells compatible with the relocation of the bulk of the carotenoids in the cell from functionally and structurally heterogeneous photosynthetic apparatus to the more homogenous lipid matrix of the oleosomes. Two-photon FLIM highlighted the pigment transformation in the cell during the stress-induced carotenogenesis. The structures co-localized with the carotenoids with shorter τ (mainly chloroplast) shrunk, whereas the structures harboring secondary carotenoids with longer τ (mainly oleosomes) expanded. These changes were in line with the ultrastructural data (TEM). Fluorescence of B. aggregatus carotenoids, either in situ or in acetone extracts, possessed a surprisingly long lifetime. We hypothesize that the extension of τ of the carotenoids is due to their aggregation and/or association with lipids and proteins. The propagation of the carotenoids with prolonged τ is considered to be a manifestation of the secondary carotenogenesis suitable for its non-invasive monitoring with multimodal imaging.

Entangling imidazolium-based ionic liquids and melanins: A crossover study on chemical vs electronic properties and carrier transport mechanisms

Melanins (mel) are a class of pigments that are nearly ubiquitous and among the oldest compounds found in nature. However, their practical application has been limited due to their low solubility in water and in most organic solvents. Recent research on polydopamine has revealed that ionic liquids (ILs) not only enhance melanin’s dissolution but also fine-tune its redox properties through specific dipolar interactions. In this study, we expand upon previous investigations by customizing new suspensions on a broader range of melanins. Concerning ILs, we focus on imidazolium based ILs, tailoring their chemical properties (pKa) and structural characteristics (cation radius, anion radius).The melanins under consideration include synthetic polymers derived from the oxidative polymerization of 5,6-dihydroxyindole (DHI) and its 2-carboxylic acid counterpart (DHICA), as well as the natural pigment Sepiomelanin (Sepiomel), which is isolated from the ink sack of cuttlefish. Our comparative analysis between neat ILs and ILs-mel responses reveals several key findings: the increase in solubility, the tuning of the redox ability, the decrease of the ionic charge resistance (from MΩ τo kΩ); the partial removal of the electrical polarization effects and the delocalized ionic charge hopping mechanisms in conductivity; the increase of the free ionic diffusion mobility and Debye lengths. Notably, electrical transport is influenced by both the chemical features and the steric hindrance in the ILs as well as the specific type of melanin employed. These factors contribute to the high order correlation between free ionic charge densities and their corresponding Debye lengths. Consequently, our findings suggest that for these complex systems, an improved model extending beyond a simplified electrostatic interaction mechanism is required.

Natural pigments and antioxidants properties of annatto extract at various pH of distilled water solvent and extraction times

Annatto is a natural colouring agent obtained from the outer coats of the seeds of the Bixa orellana. Carotenoid pigment in annatto consists of bixin and norbixin. Pigment extraction from annatto seeds is commonly done by indirect extraction using organic solvents and direct extraction using oil or aqueous alkali. This research aims to characterize the natural pigment and antioxidants of annatto extract. The annatto was extracted by maceration using distilled water at various pH and extraction times. The distilled water pH variations used in this study were 4, 7, and 9 while the extraction times were 5, 7.5 and 10 mins. Analyzing bixin and norbixin revealed the potential of annatto extract as a natural pigment, while phenol and flavonoids disclose the potential as a natural antioxidant. The results showed that varying pH of distilled water and time of extraction influences the bixin, norbixin, total phenol, and flavonoid contents of annatto extract. Annatto extraction using distilled water produces higher levels of bixin than norbixin. The highest levels of bixin (61.06%) were built in distilled water pH 7 for 7.5 mins of extraction, while the highest levels of norbixin (30%) were produced in distilled water pH 7 for 10 mins. Extraction using pH 4 creates a higher level of total phenol while increasing the extraction time up to 10 mins decreased the total phenol content. However, high levels of flavonoids were made in extraction using alkaline pH distilled water (pH 9) for 10 mins. The results showed that all extracts have the potential as natural pigments and antioxidants.

PHOTOELECTRIC CHARACTERIZATION OF DYE SENSITIZED SOLAR CELL (DSSCS) BASED ON NITROGEN DOPED CARBON QUANTUM DOT (CQDT) AND NATURAL PIGMENT EXTRACTED FROM ROSELLE HYBISCUS SABDARIFA

Citric acid, Ammonia and distilled water were used to synthesized Nitrogen doped carbon quantum dot (CQDT) and natural pigment was extracted from Roselle Hybiscus Sabdarifa flower. These sensitizers were used to fabricate monolithic dye sensitized solar cells, using Doctor Blade technique. Three samples of DSSCs were fabricated with CQDT, Hybiscus Sabdarifa dye and Hybiscus Sabdarifa +CQDT. These fabricated cells were characterized and the optical properties of the cells fabricated shows that the maximum absorbance of CQDT, hybiscus sabdarifa and hybiscus sabdarifa + CQDT was 1.75 %, 2.38 % and 2.17 % respectively. Moreso, the bandgap energy of the CQDT is 2.25 eV while hybiscus sabdarifa and hybiscus sabdarifa + CQDT is 1.88 eV and 1.92 eV respectively. The X-ray diffraction spectrum results reveals that the synthesized cells were polycrystalline in nature. The SEM images further exhibit a nanograins, that is spread throughout the substrate surface which show a stacked like agglomeration due to glass substrate used for the synthesis. The average crystallite size obtained was about 1 to 9 nm from the XRD data. The photoelectrical properties of the CQDT, hybiscus sabdarifa and hybiscus sabdarifa + CQDT revealed that the conversion efficiency was 4.17 %, 2.63 % and 1.17% respectively. This shows that the dye adhere well with the CQDT material thereby creating space for photovoltaic activities.

Metal oxide-dispersed PDMS nanocomposite films with enhanced heat-shielding ability and optical transparency

Coatings that transmit visible light and shield near-infrared (NIR) rays of sunlight have potential applications in smart windows, thermal camouflage, and heat shielding encapsulations. Here, we report metal oxide-dispersed polymer nanocomposites as potential coating materials that possess a combination of NIR reflection and visible light transmission. Film coatings (∼600 μm) comprising nanocrystalline zinc oxide (ZnO), titanium dioxide (TiO2), and cupric oxide (CuO) in the range of 0–2 wt% in polydimethylsiloxane (PDMS) matrix are fabricated. At optimal compositions, these coatings provided up to 52 % reduction in the interior air temperature, measured at distances ∼3 cm beneath the surface, while, at the same time, retaining up to 70 % of visible light transparency. The NIR reflection may be attributed to a combination of the band gap of the pigment material and the difference between the refractive indices of the pigments and the polymer matrix. We present a design map that highlights different regimes of heat-shielding and light transmission space for PDMS nanocomposite films. The performance, when compared with existing reports, suggests that films fabricated in this work outperform previously reported polymeric coatings in providing a combination of heat shielding and optical transparency.