Intense Blue Color Research Articles

Primary color generation from white organic light-emitting diodes using a cavity control layer for AR/VR applications

Abstract In this paper, we report primary color generation method from white top-emission organic light emitting diodes (WTEOLEDs) by applying cavity control layer (CCL) for achieving high resolution display. In order to realize primary colors, we applied high efficiency two-stack WTEOLED structure with solution processed indium zinc oxide CCL. Using optically designed two-stack WTEOLED with CCL, we fabricated red, green, and blue TEOLEDs with current efficiency of 34.9, 79.5, and 3.4 cd/A, respectively. However, there is an issue of intense blue emission in the red color device due to its cavity condition. To suppress this blue emission, silver nanoparticles doped electron transfer layer and rubrene doped hole transport layer methods were successively used due to their high absorption in the blue region. By applying these two methods together, top-emission red device showed 80% reduction in blue color intensity.

Synthesis and optical properties of intense blue colors oxides based on Mn5+ in tetrahedral sites in Ba7Al2-xMnxO10+y

Mn-doped Ba7Al2-xMnxO10+y (0 ≤ x ≤ 0.7) samples with intense blue colors are successfully prepared by solid state reactions. With the increase of Mn content, the colors of compounds are tuned from cyan to ocean blue. FT-IR absorption spectrum and 27Al NMR spectrum indicate that the structure contains a dominating portion of Al–O tetrahedral sites while a small number of Al–O octahedral sites may also exist. The oxidation state of Mn is proved to be +5. Based on all the analysis, the intense blue shades of the samples are proposed as the d-d transition of Mn5+ ions in [AlO4] tetrahedral sites.

Improvement of the storage stability of C-phycocyanin in beverages by high-pressure processing

This study investigates the effect of high-pressure processing (HPP) on the structure and color stability of phycocyanin, phycocyanin-whey protein, and phycocyanin-carrageenan mixtures. All samples at pH 3.0 are very stable during HPP treatment, as evidenced by the minimal color loss and minor structural changes of phycocyanin. However, at pH 5.0 and 7.0, the materials are not stable under the same HPP treatment, losing 10–30% of the blue color intensity. Circular dichroism and intrinsic fluorescence confirmed the samples at pH 5.0 lose more secondary structure than those at pH 3.0 and pH 7.0 after HPP treatment. Electrophoresis revealed that phycocyanin-whey protein samples at pH 5.0 form large protein aggregates after HPP treatment. In addition, we also studied the stability of these HPP-treated samples under natural light exposure and found the light stability of the phycocyanin-whey protein mixture at pH 5.0 significantly improved after HPP treatment at both 450 MPa and 600 MPa. The light stability of phycocyanin-carrageenan at pH 7.0 was also improved after HPP treatment at 450 MPa. HPP treatment of the phycocyanin-whey protein and phycocyanin-carrageenan samples appears to encapsulate the blue chromophore inside the apoprotein network and decrease the attack of oxidizing radicals. This study illustrates the changes of phycocyanin under HPP treatment and yield insights to improve its storage stability under light exposure.

Gold nanozyme as an excellent co-catalyst for enhancing the performance of a colorimetric and photothermal bioassay

Advanced oxidation processes (AOPs) have recently proposed for advancing colorimetric sensing applications, owing to their excellent performance of sensitive color readout that generated from the oxidation of chromogenic substrates like 3,3′,5,5′-tetramethylbenzidine (TMB) by reactive oxygen species (ROS) of AOPs such as ·OH and ·O2− radicals. However, the efficiency of ROS generation and the related H2O2 decomposition in most AOPs is quite low especially at neutral pH, which greatly hampered the practical sensing applications of the AOPs. We herein communicated that β-cyclodextrin (β-CD)-capped gold nanoparticles (β-CD@AuNPs) can promote catalysis at neutral pH for AOP as an excellent co-catalyst. In this strategy, inorganic pyrophosphate (PPi) ions was first used to coordinate with Cu2+ and form Cu2+-PPi complex. In the presence of hydrogen peroxide, target inorganic pyrophosphatase (PPase) can hydrolyze PPi into inorganic phosphate (Pi) and release free Cu2+ simultaneously, resulting in a Cu2+-triggered Fenton-like AOP reaction. The introduced β-CD@AuNPs acts as a co-catalyst, analogous to mediators in the most co-catalyzed system, to enhance the rate-limiting step of Cu2+/Cu+ conversion in Cu2+/H2O2 Fenton-like AOP and resulting in an efficient generation of ·OH and ·O2− radicals, which further producing an intense blue color by oxidizing TMB into its oxidation product (TMBox) within a short time. Finally, this reaction system was used to simply detecting target PPase with the colorimetric and photothermal readout based on the in-situ generated TMBox indicator. More significantly, we successfully demonstrated nanozyme can serve as a co-catalyst to promote the AOP catalysis at neutral pH, and inspire other strategies to overcome the pH limitation in the AOP catalysis and expand its colorimetric and photothermometric application.

Prussian blue nanoparticles with peroxidase-mimicking properties in a dual immunoassays for glycocholic acid

Prussian Blue nanoparticles (PBNPs) were utilized in a lateral flow immunoassay (LFA) and in an indirect competitive nanozyme-linked immunosorbent assay (icELISA), respectively, for their intense blue color and peroxidase (POx) -like activity. The PBNPs with good POx-like activity was linked to the antibody. Under the optimal parameters, both the PBNP-icELISA and PBNP-LFA perform very well. The icELISA has an IC50 value of 190 ng/mL, the working range extends from 29 to 1200 ng/mL, and the limit of detection is 22 ng/mL. The visual cut-off limit is 10 ng/mL. The dual immunoassay was used to quantify glycocholic acid in spiked human urine. Excellent recoveries and correlation between the two methods were observed.

Sulfur, the Versatile Non-metal.

The non-metallic chemical element sulfur, 3216S , referred to in Genesis as brimstone and identified as element by Lavoisier, is the tenth most abundant element in the universe and the fifth most common element on Earth. Important inorganic forms of sulfur in the biosphere are elemental sulfur (S8), sulfate (SO2-4), and sulfide (S2-), sulfite (SO2-3), thiosulfate, (S2O23), and polythionates (S3O62-; S4O62-). Because of its wide range of stable oxidation states, from +6to -2, sulfur plays important roles in central biochemistry as a structural and redoxactive element and is intimately related to life on Earth. Unusual reaction pathways involving sulfur compounds become possible by the specific properties of this element. Sulfur occurs in all the major classes of biomolecules, including enzymes, proteins, sugars, nucleic acids, vitamin cofactors, and metabolites. The flexibility of these biomolecules follows from its versatile chemistry. The best known sulfur mineral is perhaps pyrite (Fool's gold), with the chemical formula, FeS2. Sulfur radical anions, such as [S3].-, are responsible for the intense blue color of lapis lazuli, one of the most desired and expensive artists' materials. In the microbial world, inorganic sulfur compounds, e.g., elemental sulfur and sulfate, belong to the most important electron acceptors. Studies on microbial sulfur metabolism revealed many novel enzymes and pathways and advanced the understanding on metabolic processes used for energy conservation, not only of the microbes, but of biology in general. Transition metal sulfur complexes display intriguing catalytic activities, they provide surfaces and complex cavities in metalloenzymes that activate inert molecules such as H2, CO, N2 or N2O, and they catalyze the transformations of numerous organic molecules. Both thiamine diphosphate- (ThDP) and S-adenosyl- L-methionine- (SAM) dependent enzymes belong to Nature's most powerful catalysts with a remarkable spectrum of catalytic activities. In conclusion, given sulfur's diverse properties, evolution made an excellent choice in selecting sulfur as one the basic elements of life.

Milk colloidal system as a reaction medium and carrier for the natural blue colorant obtained from the cross-linking between genipin and milk proteins

A promising natural blue colorant was obtained from the cross-linking between genipin and milk proteins. Milk was simultaneously used to extract genipin from the unripe genipap (Genipa americana L.) and evaluated as a reaction medium and carrier for the novel blue colorant. The effects of the milk composition (skimmed, semi-skimmed, and whole) on the kinetic of blue color formation in the colorant-loaded milk samples during their cold storage time for 96 h were evaluated using their color parameters and free-genipin content. The reaction between milk proteins and genipin were evaluated by FTIR spectroscopy. In addition, the blue colorant-loaded milk samples were characterized according to their droplet size distribution, microstructure, and phase separation kinetics. The milk fat content influenced the genipin recovery while the milk with higher protein content contributed to obtaining a more intense blue color. Using whole milk with 3.0 g/100 g fat content favored the light scattering and, thus, a blue colorant with a more intense −b∗ and L∗ values was obtained. On the other hand, the use of skimmed milk with 0.5 g/100 g fat content resulted in more consumption of genipin due to its more protein content for the reaction of blue color compounds formation. Thus, a more intense and darker blue coloration was observed with lower light scattering. The milk composition did not modify the phase separation kinetics of the blue colorant-loaded milk. Therefore, our results have demonstrated that the milk was a suitable medium for the reaction of blue color formation and also a good blue compounds carrier. Industrial relevanceConsumer demands for natural colorants have increased in the last years.Thus, the new food industry challenge is to develop novel healthy, safe and high-quality food products based on natural colorants. Currently, the colorant market does not have still available a natural blue colorant. Therefore, the development of a novel natural blue colorant from plant material could meet this worldwide demand increasing the added value of many products such as ice cream, dairy beverages, and candies.

Exploiting N−H–π Interactions in 2‐(Dimesitylboraneyl)‐1H‐pyrrole for Luminescence Enhancement

AbstractDesign and development of stable blue emitters are challenging owing to their potential applications in displays and lighting technologies. Triarylborane (TAB) with suitable donors has been extensively exploited in several fields. We report herein the synthesis and structural characterization of a simple 2‐(dimesitylboryl)‐1H‐pyrrole (2) and its precursor N‐Boc‐(dimesitylboryl)‐pyrrole (1). In the crystal lattice of 2, supramolecular dimer was formed by strong N−H–π (2.59 Å) hydrogen bonding interactions between the monomers and this dimer is further connected by weak van der Waals interactions (C−H–π) with neighbouring dimers to form a supramolecular network. There is no solvatochromism noted in the absorption spectra, however significant positive solvatochromism was observed in the fluorescence spectra; points to the polar nature of excited state of 1 and 2. Compound 2 showed intense and efficient blue color luminescence in the solid state than that of 1. Thus, N−H–π interactions and π‐excessive nature of pyrrole are responsible for the above features. Impressively, compounds 1 and 2 exhibit the phosphorescence emission with a long‐lived lifetime of ∼0.55 s at 77 K and delayed fluorescence at room temperature. DFT/TD‐DFT calculations were performed to support the experimental observations.

Effect of leaf lamina colour on the behavioral characteristics of Deltocephalus menoni (Hemiptera: Cicadellidae); A vector of sugarcane white leaf disease

Deltocephalus menoni is the only locally- identified vector of Sugarcane White Leaf Disease (WLD) in Sri Lanka. Leaf lamina colour of sugarcane plants is one of the major characteristics that effects on approach and arrest of the vector during initial colonization. Differences in population levels of D. menoni have been recorded in sugarcane fields which were maintained in a similar manner with different varieties of same age. This study conducted at the Entomology Laboratory of the Sugarcane Research Institute (SRI), Uda Walawe aimed to detect the effect ofleaf lamina colour of sugarcane varieties on the behavioral characteristics of D. menoni. Leaf lamina colour of ten sugarcane verities and behavioral characteristicsof D. menoni on these varieties were studied. Pearson correlation coefficient test was performed to detect the associationsexisting between leaf lamina colour and insect behavioral characteristics Red colour had significant and negative correlations with the aggregation, amount of feeding, rate of nymphs convert into adult and adult longevity but not withthe nymphal period and oviposition. The green colour had significant and negative correlations with the amount of feeding and adult longevity of D.menonibut not with rate of nymphs convert into adult, nymphal period and oviposition. No significant correlations were found between behavioral characteristics of D. menoni and blue color intensity, hue, overall leaf colour saturation and brightness of the leaves. Results imply that higherintensities of red and green colour compositions in leaf lamina cause for making the plant less attractive for aggregation, insect feeding, nymphal period and adult longevity of D. menoni.

The Subjective and Objective Assessment of Color Selection and Light Intake with Regard to Employee Performance

Employees’ physical and mental health is significantly influenced by the light intensity and color environment of their workstations. The goal of this research was to determine the influence of workspace color variations and lighting intensity on employees’ physical and mental comfort. Objective assessment by measuring physical condition including heart rate and blood pressure using the design of experiment methods (DOE). The subjective rating using the National Aeronautics and Space Administration Task Load Index (NASA-TLX) method is to perform a working mental burden measurement consisting of six-dimensional indicators including Mental Demand, Physical Demand, Temporal Demand (TD), Own Performance, Frustration Level, Effort. Measurements were recorded before and after the color and intensity of the light in a three-meter long, three-meter wide, and three-meter high chamber by adjusting the color of the walls to red, blue, or white and noting changes in the physical environment and the respondent's mental stress level. Objective measurement tests for DOE included measuring degrees of physical comfort using blue and lighting from 300 lux to 350 lux. The highest ranking was systole of 100.9 mmHg, down 5.48%; diastole, down 2.71%; and heart rate, down 2%. The same thing occurred in measuring the level of mental comfort with NASA TLX: the blue color and light intensity of 300 lux to 350 lux produced the lowest stress value of 55.67, down 18.40%. Results showed the effect of the blue color and the lighting can lower the blood pressure, heart rate, and mental burdens of employees, thus improving employees’ comfort.

Secure RGB image steganography based on modified LSB substitution

Different steganography techniques have been presented based on RGB image as the image is considered secure cover for hidden data. Specifically, this paper presents edge-based image steganographic method using parameterised Canny edge detector that relies on embedding the secret message bits into variable LSB length of the blue colour channel of the cover image. The blue colour channel is selected because the steganography-based research showed that the visual perception of blue colour intensity is less distinct than the red and green colours. Secret message bits are embedded up to four bits of LSB which are selected by a random number generator. Additionally, as the less significant information is carried out by the LSB of each pixel so slight changes of LSB will not affect the visual quality of the cover image. The proposed algorithm was tested on a set of RGB colour images, and satisfactory results were demonstrated regarding minimum distortion in the blue colour of a pixel and visually identical original and stego image.

Hibonite Blue: A New Class of Intense Inorganic Blue Colorants.

Commercially available spinel cobalt blue (CoAl2O4) utilizes a significant amount of carcinogenic Co2+, which makes its synthesis more hazardous and environmentally harmful. Considerable effort has been put into developing more environmentally benign and robust blue pigments to replace cobalt blue. A new class of blue pigments with tunable hue were prepared. The solid solution series, CaAl12–2xCoxTixO19 (0 < x ≤ 1), crystallizes in a hexagonal mineral hibonite (CaM12O19) structure with five distinct crystallographic sites for M cations (M = Al, Co, and Ti). The origin of intense blue color is attributed to a synergistic effect of allowed d–d transitions involving the chromophore Co2+ in both tetrahedral and trigonal bipyramidal crystal fields. Compared with commercial cobalt blue, these tunable hibonite blues possess a reddish hue that intensifies the blue color as observed in Y(In,Mn)O3 (YInMn) blues, with a significant reduction of Co2+ concentration from 33% to as low as 4% by mass. A significant advantage of hibonite blues over cobalt blue is the substantial reduction in carcinogenic cobalt content while enhancing the color properties at a reduced cost for raw materials.

AeBlue Chromoprotein Color is Temperature Dependent.

BackgroundMarine sessile organisms display a color palette that is the result of the expression of fluorescent and non-fluorescent proteins. Fluorescent proteins have uncovered transcriptional regulation, subcellular localization of proteins, and the fate of cells during development. Chromoproteins have received less attention until recent years as bioreporters. Here, we studied the properties of aeBlue, a a 25.91 kDa protein from the anemone Actinia equina.ObjectiveTo assess the properties of aeBlue chromoprotein under different physicochemical conditions.MethodsIn this article, during the purification of aeBlue we uncovered that it suffered a color shift when frozen. We studied the color shift by different temperature incubation and physicochemical conditions and light spectroscopy. To assess the possible structural changes in the protein, circular dichroism analysis, size exclusion chromatography and native PAGE was performed.ResultsWe uncover that aeBlue chromoprotein, when expressed from a synthetic construct in Escherichia coli, showed a temperature dependent color shift. Protein purified at 4 °C by metal affinity chromatography exhibited a pinkish color and shifts back at higher temperatures to its intense blue color. Circular dichroism analysis revealed that the structure in the pink form of the protein has reduced secondary structure at 4 °C, but at 35 °C and higher, the structure shifts to a native conformation and Far UV- vis CD spectra revealed the shift in an aromatic residue of the chromophore. Also, the chromophore retains its properties in a wide range of conditions (pH, denaturants, reducing and oxidants agents). Quaternary structure is also maintained as a tetrameric conformation as shown by native gel and size exclusion chromatography.ConclusionOur results suggest that the chromophore position in aeBlue is shifted from its native position rendering the pink color and the process to return it to its native blue conformation is temperature dependent.

Highly Stable Colorimetric Sensing by Assembly of Gold Nanoparticles with SYBR Green I: From Charge Screening to Charge Neutralization.

Aggregation of plasmonic gold nanoparticles (AuNPs) has been widely used for label-free colorimetric sensing. Adding salt is a commonly used method to induce a color change, but salt-induced aggregation by charge screening is a slow kinetic process, making quantitative and reproducible measurement difficult. Herein, we explored an alternative method by charge neutralization using positively charged molecules, such as a DNA-staining dye, SYBR Green I (SG), for efficient and stable assembly of AuNPs. Even submicromolar SG effectively triggered the aggregation of AuNPs in less than 1 min, and the resulting intense blue color was stable for over 10 h. The charge neutralization effect of SG was confirmed with zeta potential measurements. Besides, pH-dependent aggregation of AuNPs by SG agreed well with the pKa of the nitrogen atoms responsible for the positive charges in the SG structure. Moreover, the charge neutralization effect was also observed from polycations such as polyamines. The SG-induced assembly of AuNPs was developed into a label-free colorimetric sensing platform. Benefiting from the intense blue color, this new sensing strategy allowed visual detection of as low as 0.1 nM DNA, 50-fold lower than that by salt. Such a charge neutralization strategy may inspire further thinking on fundamental colloidal science and its applications in analytical chemistry. This work itself significantly improved AuNP-based colorimetric sensors in terms of detection time, signal stability, and sensitivity.

Injury-Triggered Blueing Reactions of Psilocybe "Magic" Mushrooms.

Upon injury, psychotropic psilocybin‐producing mushrooms instantly develop an intense blue color, the chemical basis and mode of formation of which has remained elusive. We report two enzymes from Psilocybe cubensis that carry out a two‐step cascade to prepare psilocybin for oxidative oligomerization that leads to blue products. The phosphatase PsiP removes the 4‐O‐phosphate group to yield psilocin, while PsiL oxidizes its 4‐hydroxy group. The PsiL reaction was monitored by in situ 13C NMR spectroscopy, which indicated that oxidative coupling of psilocyl residues occurs primarily via C‐5. MS and IR spectroscopy indicated the formation of a heterogeneous mixture of preferentially psilocyl 3‐ to 13‐mers and suggest multiple oligomerization routes, depending on oxidative power and substrate concentration. The results also imply that phosphate ester of psilocybin serves a reversible protective function.

Injury‐Triggered Blueing Reactions of Psilocybe “Magic” Mushrooms

AbstractUpon injury, psychotropic psilocybin‐producing mushrooms instantly develop an intense blue color, the chemical basis and mode of formation of which has remained elusive. We report two enzymes from Psilocybe cubensis that carry out a two‐step cascade to prepare psilocybin for oxidative oligomerization that leads to blue products. The phosphatase PsiP removes the 4‐O‐phosphate group to yield psilocin, while PsiL oxidizes its 4‐hydroxy group. The PsiL reaction was monitored by in situ 13C NMR spectroscopy, which indicated that oxidative coupling of psilocyl residues occurs primarily via C‐5. MS and IR spectroscopy indicated the formation of a heterogeneous mixture of preferentially psilocyl 3‐ to 13‐mers and suggest multiple oligomerization routes, depending on oxidative power and substrate concentration. The results also imply that phosphate ester of psilocybin serves a reversible protective function.

Interaction of Genes Controlling Some Morphological Features of Flax (Linum usitatissimum L.)

The interaction of 11 genes of flax which control the color of the hypocotyl, flowers and seeds, as well as deformation of petals, was evaluated by genetic analysis. All these genes have pleiotropic effects on several parts of a flower and sometimes on hypocotyl and seeds. Four genes affect the shape and intensity of flower color: s1 (complete stop of anthocyanin synthesis, corolla deformation), sfbs1 (inhibition of anthocyanin synthesis in flower, slightly deformed corolla), pbc1 and pbc3 (very light blue flower with different degrees of corolla deformation). Six genes cause a dilution of the blue color of the flower: wf1 (white), f e (very light blue, spotted seeds), dlb1, dlb3, dlb4 (different intensity of light blue color), ora1 (lighter than blue, orange anthers, yellow speckles on red-brown seeds), and pf (pink flower and seeds with yellow hue). The basic scheme of interaction between genes controlling color and shape of flax flowers can be represented as follows: s1 > sfbs1 > wf1 > pf1 > f e > pbc1 > pbc3 > dlb1 > dlb3 > ora1. However, the sequence of functioning of the s1, wf1, pf1, f e, and dlb3 genes changes during the formation of different features. For example, for flower color, they will be arranged as follows: s1 > wf1 ≥ pf1 ≥ f e ≥ dlb3; for flower deformation: pf1 = wf1 > dlb3 > s1 > f e; for seed color: pf1 > s1 > f e > wf1 = dlb3.

High quality, highly transparent Cu incorporated WO3 thin films suitable for blue LED application

Good crystalline Cu doped WO3 thin films are prepared using Radio Frequency (RF) magnetron sputtering and the films are characterised using various characterisation tools. Structural study using X-ray diffraction technique (XRD) and Micro-Raman Spectroscopy confirms the formation of monoclinic WO3 phase in all the films. The prepared films are preferentially oriented along a-axis and the film with 3 wt% Cu concentration show better crystalline quality. Morphological analysis (Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM)) and elemental analysis (Energy Dispersive X-ray Spectroscopy (EDX)) show that Cu nanoparticles can act as seeding sites for the formation of bigger clusters in the films. The valence states of Cu in the prepared thin films are found to be +2 and 0 and/or +1 using X-ray Photoelectron Spectroscopic (XPS) study. The dip in the transmittance spectra and the corresponding enhanced absorption in the absorbance spectra around 620 nm region of 5 and 7 wt% Cu doped films detected using UV–Visible analysis can be attributed to localised surface plasmon resonance (LSPR) behaviour of Cu nanoparticles in these films. LSPR behaviour of Cu nanoparticles at higher Cu doped films suggests their suitability for improving the quantum efficiency of various photonic devices. A band gap renormalisation from 3.14 eV to 2.97 eV can be observed with increase in Cu incorporation concentration. Emission behaviour of Cu doped WO3 films are studied for their visible colour perception which show chromaticity coordinates corresponding to intense blue colour. The intense blue emission from Cu doped WO3 thin films suggests their suitability in blue light emitting diodes and in phosphor converted white light emitting diodes.

Epitaxial characteristics of MBE-grown ZnTe thin films on GaAs (211)B substrates

Highly crystalline ZnTe thin films were grown on GaAs (211)B substrates by molecular beam epitaxy (MBE) for potential applications such as MCT detectors and optoelectronic devices. We investigated the effects of Te to Zn (VI/II) flux ratio on the quality of ZnTe films in terms of crystal orientation, elemental composition, surface roughness, and dislocation density. Atomic concentrations of Zn, Te, and oxygen complexes due to oxygen contamination on the film surfaces were analyzed by X-ray photoelectron spectroscopy. X-ray double crystal rocking curve full width half maximum (FWHM) of ZnTe (422) peak was observed as 233 arcseconds for a 1.66 μm thick film, which indicates high crystallinity. Wet chemical etching was applied to the films to quantify the crystal quality by calculating etch pit densities (EPD) from scanning electron microscope images. A very low EPD value of 1.7 × 107 cm−2 was measured. Additionally, the root mean square roughness values, obtained from atomic force microscopy topography images were in the range of 10–25 nm. These values were supported by FWHM values of red green blue color intensity histograms obtained from Nomarski Microscope images. The results of our analyses indicate that the VI/II flux ratios of 4 and 4.5 produce the best quality ZnTe films on GaAs (211)B substrates.

Preparation of topographically remarkable cobalt microspheres for colorimetric detection of dopamine and elucidation of its sensing mechanism

In this work, a new colorimetric probe is prepared and demonstrated for the detection of dopamine (DA), an important neurotransmitter. The proposed colorimetric probe is prepared using bovine serum albumin (BSA) modified cobalt hydroxide microspheres (CoMSPs@BSA) and subsequently explored for the selective colorimetric detection of DA. The sensing studies are monitored using UV–visible absorbance spectroscopy. Interestingly upon addition of DA, an intense blue color is formed suggesting the potential use of this probe for naked eye detection of DA. The mechanism behind the sensing is investigated using time dependent UV–visible absorbance spectroscopic study and cyclic voltammetry. These studies clearly indicate the ligand exchange reaction is responsible for the resultant blue color formation. Further using this colorimetric probe a concentration range from 5.3 to 211 µM DA could easily be detected. Limit of detection of this DA sensor is found to be 5 × 10−6 M. Similarly a linear relation is observed from the calibration graph plotted between the concentration and absorption intensity corresponding to ligand exchange of BSA by DA. Moreover, this sensing probe (CoMSPs@BSA) is found to be highly selective among a wide range of other commonly interfering biomolecules. Topographically remarkable cobalt microspheres are prepared using a simple method and explored for the colorimetric detection of dopamine. The sensing mechanism is elucidated using UV–visible spectroscopic and electrochemical studies.