Dicyclohexylcarbodiimide Research Articles

Plasma Surface Polymerized and Biomarker Conjugated Boron Nitride Nanoparticles for Cancer-Specific Therapy: Experimental and Theoretical Study.

A new low-pressure plasma-based approach to activate the surface of BN nanoparticles (BNNPs) in order to facilitate the attachment of folate acid (FA) molecules for cancer-specific therapy is described. Plasma treatment of BNNPs (BNNPsPT) was performed in a radiofrequency plasma reactor using ethylene and carbon dioxide monomers. The carboxyl groups deposited on the surface of BNNPsPT were activated by N,N’-dicyclohexylcarbodiimide (DCC) and participated in the condensation reaction with ethylene diamine (EDA) to form a thin amino-containing layer (EDA-BNNPPT). Then, the DCC-activated FA was covalently bonded with BNNPsPT by a chemical reaction between amino groups of EDA-BNNPsPT and carboxyl groups of FA. Density functional theory calculations showed that the pre-activation of FA by DCC is required for grafting of the FA to the EDA-BNNPsPT. It was also demonstrated that after FA immobilization, the electronic characteristics of the pteridine ring remain unchanged, indicating that the targeting properties of the FA/EDA-BNNPsPT nanohybrids are preserved.

Surface-exposed domains of TatB involved in the structural and functional assembly of the Tat translocase in Escherichia coli

Twin-arginine-dependent translocases transport folded proteins across bacterial, archaeal, and chloroplast membranes. Upon substrate binding, they assemble from hexahelical TatC and single-spanning TatA and TatB membrane proteins. Although structural and functional details of individual Tat subunits have been reported previously, the sequence and dynamics of Tat translocase assembly remain to be determined. Employing the zero-space cross-linker N,N'-dicyclohexylcarbodiimide (DCCD) in combination with LC-MS/MS, we identified as yet unknown intra- and intermolecular contact sites of TatB and TatC. In addition to their established intramembrane binding sites, both proteins were thus found to contact each other through the soluble N terminus of TatC and the interhelical linker region around the conserved glutamyl residue Glu49 of TatB from Escherichia coli Functional analyses suggested that by interacting with the TatC N terminus, TatB improves the formation of a proficient substrate recognition site of TatC. The Glu49 region of TatB was found also to contact distinct downstream sites of a neighboring TatB molecule and to thereby mediate oligomerization of TatB within the TatBC receptor complex. Finally, we show that global DCCD-mediated cross-linking of TatB and TatC in membrane vesicles or, alternatively, creating covalently linked TatC oligomers prevents TatA from occupying a position close to the TatBC-bound substrate. Collectively, our results are consistent with a circular arrangement of the TatB and TatC units within the TatBC receptor complex and with TatA entering the interior TatBC-binding cavity through lateral gates between TatBC protomers.

Synthesis of Methylcytisine 9-Thiocarboxamides

9-Carboxamide derivatives of the quinolizidine alkaloid methylcytisine were synthesized. The synthetic pathway included nitration-reduction according to the literature that resulted in 9-amination of the 2-pyridone core of the starting alkaloid. The obtained 9-amino derivative was converted by CS2 in Py in the presence of dicyclohexylcarbodiimide (DCC) into the corresponding isothiocyanate. The synthesized 9-isothio derivative was reacted with primary and secondary amines. The yields of the obtained 9-thiocarboxamide methylcytisine derivatives were 80–98%. The structures of the synthesized compounds were established using elemental analyses and IR, PMR, 13C NMR, and 15N NMR spectroscopy.

Magnetic Nanoparticles As a Biological Sensors for Early Diagnosis and Treatment of Cancer Cells

Recently, Nano-bio interactions become very attractive due to their early disease diagnosis and therapy. Furthermore, studies of these nano-particles and their interactions with healthy tissues and organs have enabled new approaches for the precise control of off-target nano-particle clearance, which is equally important as disease targeting. For this reason, coating them with bio-compatible agents became necessary for in vitro and in vivo applications. In this research, magnetic nano-particles synthesized by chemical decomposition method and coated with the bio-compatible agents around them. Besides, as-synthesized RMNPs powders were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM/EDAX), Fourier transforms infrared spectroscopy (FT-IR), Vibrating sample magnetometry (VSM), and Zeta Potential analyser. In order to conjugate several Biological agents, zero-length crosslinkers such as 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) or dicyclohexylcarbodiimide (DCC) which makes use of carbodiimide chemistry to covalently bond a primary or secondary amine to the alpha carbon of a carboxylate group has been used to forming an amide linkage. On the surface of these nano-particles, fluorescent agents have been used in order to early diagnosing of cancer cells. For this purpose, Bio-compatible peptide-based Nano-systems proposed to demonstrate the fluorescence. On the one hand, due to the magnetic nature of these nano-particles with high magnetization (~80 emu/g) succeeded to guide them to the exact location of tumors and also we used hyperthermia cancer therapy. On the other hand, by mounting the photosensitizer agents on the surface of these nano-particles, activated these agents by stimulating them in the specific wavelengths (450 nm), so, this help us to damage tumor cells by a photodynamic method. Also, these nano-particles were able to use as a cargo for anti-cancer drugs. As, Arginylglycylaspartic acid (RGD) peptides, are designed, fabricated, and experimentally validated for drug delivery and imaging they were a good candidate for this purpose. So that, these nano-particles used to encapsulate anti-cancer drugs such as Cisplatin, Doxorubicin and, 5fluorouracil. Multi-functionalized MNPs not only have the ability of early detection of illnesses, including tumor cells, but also, by engineering their surface, we succeeded to damage the tumor cells in the Multilateral way. 1-Du B, Yu M, Zheng J. Transport and interactions of nanoparticles in the kidneys. Nature Reviews Materials. 2018 Aug 3:1. 2- Bagherpour AR, Kashanian F, Ebrahimi SS, Habibi-Rezaei M. L-arginine modified magnetic nanoparticles: green synthesis and characterization. Nanotechnology. 2018 Jan 15;29(7):075706. 3- Shi D, Sadat ME, Dunn AW, Mast DB. Photo-fluorescent and magnetic properties of iron oxide nanoparticles for biomedical applications. Nanoscale. 2015;7(18):8209-32. 4- Jin D, Xi P, Wang B, Zhang L, Enderlein J, van Oijen AM. Nanoparticles for super-resolution microscopy and single-molecule tracking. Nature methods. 2018 May 28:1. 5- Fan Z, Chang Y, Cui C, Sun L, Wang DH, Pan Z, Zhang M. Near infrared fluorescent peptide nanoparticles for enhancing esophageal cancer therapeutic efficacy. Nature communications. 2018 Jul 4;9(1):2605. 6- Zhang J, Jiang C, Longo JP, Azevedo RB, Zhang H, Muehlmann LA. An updated overview on the development of new photosensitizers for anticancer photodynamic therapy. Acta pharmaceutica sinica B. 2018 Mar 1;8(2):137-46. Figure 1

Fabrication of amine functionalized graphene oxide – AgNPs nanocomposite with improved dispersibility for reduction of 4-nitrophenol

In the present work, graphene oxide (GO) was synthesized through modified Hummer's method and the covalent functionalization of GO was achieved via amino moiety using N,N′-dicyclohexylcarbodiimide (DCC) as coupling agent and ethylenediamine (EDA) & 1,3-diaminopropane (DAP) as amino precursors. The amino functionalized GO served as nucleation and growth sites for silver nanoparticles. These two amino functionalized graphene oxide-AgNPs were compared based on the chain length of the alkyl-diamine and metal loading capacity. Further, these two nanocomposites were characterized using FTIR, UV, Raman, XPS and TEM analyses. We reported that these alkyl-diamine-functionalized graphene oxides had superior dispersibility in different polar solvents with reduced agglomeration of Ag nanoparticles and had control over the size of Ag nanoparticles in the range of 5–10 nm. The catalytic efficiency of these two types of amine functionalized GO-AgNPs nanocomposite were assessed based on the reduction of 4-nitrophenol. The reduction outcomes revealed that the kobs value for DAP functionalized AgNPs (7.548 × 10−4 s−1) was comparatively superior than GO-EDA-AgNPs (3.345 × 10−4 s−1) due to the variation in chain length. Optimization of parameters like [substrate], [NaBH4] and catalyst load was also investigated and found to possess influence on kobs values.

PH-RESPONSIVE CARBOXYMETHYL CELLULOSE CONJUGATED SUPERPARAMAGNETIC IRON OXIDE NANOCARRIERS

In the present study, polyethyleneimine (PEI) coated superparamagnetic iron oxide nanoparticles (SPIONs) having the size of 15 nm in diameter with high magnetic saturation (60 emu/g) have been prepared by co-precipitation method. The synthesized PEI-Fe3O4 nanoparticles have been fully characterized by transmission electron microscope (TEM), dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques. The free amine groups on the PEI-Fe3O4 surface has been covalently functionalized with carboxymethyl cellulose (CMC) by the catalysis of N,N'-Dicyclohexylcarbodiimide (DCC) and N, N'-Dimethylpyridin-4-amine (DMAP) coupling to produce CMC-Fe3O4 nanocarriers. The prepared CMC-Fe3O4 nanocarriers have been loaded with a well-known anti-tumor drug doxorubicin (Dox) and investigated its loading and releasing profiles from the nanocarrier. The CMC acted as an excellent nanocarrier for Dox with a loading efficiency ≈ 86%. The drug releasing profile has been studied at different pH values (3.5; 5.5; and 7.4). When the pH of the release medium (phosphate buffer solution) was changed from 7.4 to 5.5 or 3.6, the drug release has been increased which indicates that the drug releasing is pH dependent.

Simple one pot synthesis of ketone from carboxylic acid using DCC as an activator

Simple one pot procedure for the conversion of carboxylic acid to ketone is described. Various carboxylic acids were converted to the corresponding ketones in excellent manner in presence of N,N′-dicyclohexylcarbodiimide (DCC) and organometallic reagents. Aromatic, heteroaromatic and aliphatic acids were converted to the corresponding ketones smoothly under the optimum conditions using organolithium reagents. In this process, desired products have been isolated from the crude reaction mixtures in moderate yields during the purification process.

Amides Derived from Vanillic Acid: Coupling Reactions, Antimicrobial Evaluation, and Molecular Docking

A series of amides derived from vanillic acid were obtained by coupling reactions using PyBOP ((Benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate) and DCC (Dicyclohexylcarbodiimide) coupling reagents. These were submitted to biological evaluation for species of Candida, Staphylococcus, and Pseudomonas. The microdilution method in broth was used for the antimicrobial testing to determine the Minimum Inhibitory Concentration (MIC) and to verify the likely mechanism of action for antifungal activity. The ten amides were obtained with yields ranging from 28.81 to 86.44%, and three compounds were novel. In the antibacterial evaluation, the amides (in their greatest concentrations) were bioactive against Staphylococcus aureus strain ATCC 25925. Meanwhile, all of the tested amides presented antifungal activity against at least one strain. The amide with best antifungal profile was compound 7, which featured an MIC of 0.46 μmol/mL, and a mechanism of action involving the plasma membrane and fungal cell wall. The presence of a methyl group in the para position of the aromatic ring is suggested which enhances the activity of the compound against fungi. Docking studies of the ten compounds using the protein 14α-demethylase as a biological target were also performed. The biological results presented good correlation with molecular docking studies demonstrating that a possible site of antifungal action for bioactive amides is the enzyme 14α-demethylase.

Novel diamide ligands with a central carbonyl group and their comparative evaluation with the diglycolamide ligand: synthesis, extraction, DFT and chromatographic studies

Abstract The extraction behaviour of U(VI), Th(IV) and Nd(III) was investigated as a function of nitric acid concentration for diamide based extractants, namely, N,N,N′,N′-tetraoctyl-3-carbonylpentanediamide (TOCPDA) and 4-carbonyl-heptanedioic acid bis-dioctylamide (CHADA). In addition, the distribution ratio was also measured for Pu(IV) and Sr(II) with 1.1 M CHADA in n-dodecane. These extractants were synthesized by adopting simple acid, amine coupling reaction with DCC (dicyclohexylcarbodiimide) and DMAP (N,N′-dimethylaminopyridine) as the coupling agent. The newly synthesized extractants were characterized by FT-IR, NMR, Mass, CHNS and HPLC. The extraction results indicated that CHADA shown has better extraction behavior for U(VI) compared to TOCPDA. In addition, CHADA coated HPLC column was examined for the retention behaviour of U(VI), Th(IV), and Nd(III). Computation studies based on density functional theory (DFT) were carried out to understand the complexing behaviour of U(VI), Pu(IV) and Sr(II) with CHADMA and TMCPDA.

Design, Synthesis and Anticancer Activity of Site Specific Short Chain Cationic Peptide

In spite of current progress in treatment methods, cancer is a major source of morbidity and death rate all over the world. Traditional chemotherapeutic agents aim to divide cancerous cells, are often associated with deleterious side effects to healthy cells and tissues. Host defense peptides Cecropin A and B obtained from insects are capable to lyses various types of human cancer cells at peptide concentrations which are not fatal to normal eukaryotic cells. In the present work we have designed short chain α-helical linear and cyclic peptide from cecropin A having same cationic charge, hydrophobicity and helicity. Synthesis of designed novel short chain linear (10) and cyclic compound (12) was accomplished by using solution phase method. All the coupling reactions were carried out by using dicyclohexylcarbodiimide (DCC) as the coupling reagent at room temperature in the presence of N-methylmorpholine (NMM) as the base. The Structure of newly synthesized peptidse were elucidated by 1H-NMR, 13C-NMR, FT-IR, FABMS and elemental analysis data.Cytotoxicity of synthesized compound was tested against Dalton's Lymphoma Ascites (DLA), Ehrlich's Ascites Carcinoma (EAC) and MCF-7 cell lines by using MTT assay and 5-FU as reference compound. From biological assessment,it was found that short chain cyclicpeptide12 showed high level of cytotoxic activity against DLA and EAC cell lines. By utilizing a structure-based rational approach to anticancer peptide design from cecropin A, we were able to develop short chain linear and cyclic peptides having same charge, hydrophobicity and with improved activity. Systematically removing amino acids, we were able to retaining peptide charge and hydrophobicity/hydrophilicity in linear and cyclic peptide which results to optimize the anticancer activity against DLA and EAC cell lines.

Covalently binding mucoadhesive polymers: N-hydroxysuccinimide grafted polyacrylates

AimThe aim of the study was to establish a novel type of covalently mucus-binding polymers by targeting selectively amino groups within mucus glycoproteins. MethodsN-Hydroxysuccinimide (NHS) was attached to carboxylic groups of polyacrylic acid (PAA). The reaction was mediated by the coupling reagent N,N′-dicyclohexylcarbodiimide (DCC) achieving polymeric NHS esters being able to form amide bonds with free amino groups. The chemical structure of the obtained conjugates was characterized via FTIR- and UV spectroscopy. Reactivity towards mucosal amino groups was evaluated UV spectrometrically upon addition of L-glycine. Furthermore, tensile force evaluations on intestinal mucosa as well as rheological experiments with mucus were performed in order to prove mucoadhesive potential. ResultsDepending on the amount of NHS added to the synthesis, coupling rates of 876 to 1820 µmol NHS per gram polymer were obtained. Kinetic studies of amide bond formation showed a substrate dependent reaction velocity. Rheological synergism of PAA-NHS was proven by a 7.9-fold increased mucus viscosity compared to the control polymer. In further mucoadhesion studies PAA-NHS showed a 5.5-fold improved adhesion time compared to unmodified PAA. Tensile force evaluation confirmed these results with a 1.7-fold higher maximum detachment force (MDF) and 2.7-fold increased total work adhesion (TWA) for PAA-NHS compared to the unmodified control polymer. ConclusionThe results of the present study provide strong evidence that coupling NHS to polymers could be a promising tool for the development of novel mucoadhesive excipients.

Evidence for Escherichia coli DcuD carrier dependent FOF1-ATPase activity during fermentation of glycerol

During fermentation Escherichia coli excrete succinate mainly via Dcu family carriers. Current work reveals the total and N,N’-dicyclohexylcarbodiimide (DCCD) inhibited ATPase activity at pH 7.5 and 5.5 in E. coli wild type and dcu mutants upon glycerol fermentation. The overall ATPase activity was highest at pH 7.5 in dcuABCD mutant. In wild type cells 50% of the activity came from the FOF1-ATPase but in dcuD mutant it reached ~80%. K+ (100 mM) stimulate total but not DCCD inhibited ATPase activity 40% and 20% in wild type and dcuD mutant, respectively. 90% of overall ATPase activity was inhibited by DCCD at pH 5.5 only in dcuABC mutant. At pH 7.5 the H+ fluxes in E. coli wild type, dcuD and dcuABCD mutants was similar but in dcuABC triple mutant the H+ flux decreased 1.4 fold reaching 1.15 mM/min when glycerol was supplemented. In succinate assays the H+ flux was higher in the strains where DcuD is absent. No significant differences were determined in wild type and mutants specific growth rate except dcuD strain. Taken together it is suggested that during glycerol fermentation DcuD has impact on H+ fluxes, FOF1-ATPase activity and depends on potassium ions.

SYNTHESIS AND EVALUATION OF NAPROXEN ESTER PRODRUGS

The present works deals with simple and efficient method of improving therapeutic efficacy of naproxen by retarding gastrointestinal side effects through masking of carboxylic group chemically. This is achieved by synthesis of ester prodrugs of naproxen with various naturally available antioxidants; menthol, thymol, eugenol, guiacol, vanillin and sesamol by the dicyclohexyl carbodiimide (DCC) coupling method. The title compounds are purified and characterized by spectral data. Further, their partition coefficients have been determined and hydrolytic studies have been performed. The synthesized compounds are more lipophilic compared to the parent moieties and are stable in acidic environment, which is a prerequisite for their oral absorption. Under gastric as well as intestinal pH conditions, these prodrugs showed variable susceptibility towards hydrolysis. The title compounds when evaluated for anti-inflammatory and analgesic activities showed improvement over the parent drug. Prodrugs were also found to be significantly less ulcerogenic then parent drugs.

Polyethyleneimine Nanofibers Functionalized with Tetradentate Schiff Base Complexes of Dioxomolybdenum(VI) as Efficient Catalysts for Epoxidation of Alkenes

AbstractThree tetradentate Schiff base ligands (H2L1‐3) were prepared from the reaction of 5‐sustituted‐2‐hydroxybenzaldehydes and 3,4‐diaminobenzoic acid. The obtained ligands were reacted with molybdenyl acetylacetonate in ethanol to prepare the corresponding dioxomolybdenum(VI) complexes (MoO2L1‐3) in good yields (80‐82%). Immobilization of the abovementioned complexes on polyethyleneimine (PEI) was achieved via condensation of carboxylic functional groups of the complex with amine functional groups of the polymer in presence of dicyclohexylcarbodiimide (DCC) and 4‐dimethylaminopyridine (DMAP). The obtained hybrid materials were then converted to electrospun nanofibers and used as recyclable catalysts for the epoxidation of alkenes.

Covalent Bonding of PANI and p‐Phenylenediamine‐Functionalized GO Using N,N′‐Dicyclohexylcarbodiimide as Dehydrating Agent for Electrochromic Applications

AbstractIn this paper, a high‐performance organic/inorganic electrochromic material was synthesized by covalent bonding of polyaniline (PANI) and graphene oxide (GO). In the presence of N,N′‐dicyclohexylcarbodiimide (DCC) as dehydrating agent, GO was functionalized by p‐phenylenediamine (PPD) through an amidation reaction. Water‐processable PANI‐GO nanocomposites were prepared by copolymerization of aniline with PPD functionalized GO in the presence of poly(styrene sulfonate) (PSS) dopant in an aqueous medium. The structures and morphologies of PANI‐GO nanocomposites were characterized by Fourier‐transform infrared (FTIR) spectra, Raman spectra, transmission electron microscope (TEM) and scanning electron microscope (SEM). The results show that covalent bonding PANI‐GO nanocomposites possess better electrochemical and electrochromic properties over that of neat PANI. With 3 wt.% GO‐PPD loading, PANI‐GO‐3% exhibits the optimal electrochemical and electrochromic properties, among which the charge‐transfer resistance (RCT) is 29.4 Ω, the optical contrast is 0.72 and coloring/bleaching time is 4.45/4.28 s. Overdose GO‐PPD leads to negative influence on the contrast and switching speed, owing to the ion blocking effect brought by its two‐dimensional nanostructure.

A study of synthesizing stable super-slip carbon nanotubes by grafting octadecylamine

A stable super-slip material with the electrical conductive property has been synthesized by chemical grafting. The multi-walled carbon nanotubes (MWCNTs) were chosen as the electrical conductive matrix. After the acidification of the mixed acid, the original MWCNTs were oxidized to form carboxyl groups on the surface. The octadecylamine (ODA) was bonded on the acidified MWCNTs with the amidation reaction. In order to obtain higher grafting rate, dicyclohexylcarbodiimide (DCC) was added into the reaction system. The MWCNTs with the ODA grifted had properties of superhydrophobic and super-slip. The modified MWCNTs properties of anti-icing, resistance of ultraviolet and acid-alkali were verified during the testing. The modified MWCNTs can be used as electrical conductors for special service, such as devices requiring hydrophobicity and super-slip.

Synthesis of cholic acid-terminated dendritic lysine-block-poly(ethylene glycol)-block-dendritic lysine and its enhanced ability to solubilize Paclitaxel in water

Paclitaxel, a chemotherapeutic drug used to inhibit mitosis in cancer cells, requires the use of the solubilizer Cremophor EL due to its poor water solubility. However, Cremophor EL is associated with adverse reactions following chemotherapy. This work reports the synthesis of an alternative solubilizing agent for paclitaxel. Two generations of dendritic lysine were coupled onto both ends of PEG-4000 via reaction of fluorenylmethyloxycarbonyl (FMOC)-lysine-FMOC-OH with dicyclohexylcarbodiimide (DCC)-mediated condensation, and deprotection with 30% piperidine. Cholic acid was attached to the terminal amino groups through the use of DCC/n-hydroxysuccinimide. Synthesis steps were monitored and confirmed by electrospray ionization mass spectroscopy. The results suggest that the synthesized polymer is a viable solubilizing agent for delivery of paclitaxel. Additional studies are required to assess its safety and stability.

Continuous Synthesis of Cyclohexene Oxide in a Micro‐FlowSystem

AbstractEpoxidation reaction catalyzed by dicyclohexylcarbodiimide(DCC) was realized in a microflow system, resulting in cyclohexene oxide with high yields. In this study, the epoxidation process of cyclohexene in MFS was investigated in detail. The optimal yield was obtained in such conditions: temperature 80°C, residence time 12 min, catalyst concentration 3%, ratio of cyclohexene to UHP 1:8. Basic additions played an important role in the collapse of adducts.

Aqueous suspension of biocompatible reduced graphene oxide- Au NPs composite as an effective recyclable catalyst in a Betti reaction

Synthesis of noble metal nanoparticles (NPs) on modified graphene oxide with biocompatible polymers has attracted significant due to their unique properties and various applications. In this research, covalent-modified graphene oxide (MGO) with diacid terminated poly (ethylene glycol) (PEG) was used as a substrate and stabilizing of Au (ш). The reduction of MGO-Au (ш) complex with hydrazine monohydrate under reflux condition obtained biocompatible reduced MGO (rMGO)-Au NPs. Diacid terminated PEG obtained from the reaction of PEG with succinic anhydride in the presence of N,N- dicyclohexylcarbodiimide (DCC) and 4-methylamino pyridine (DMAP) was attached to GO sheets to prevent from the aggregation of rMGO sheets and Au NPs. The resulting aqueous suspension was characterized through UV–vis, FT-IR, Raman, XRD, DLS-zeta potential, SEM, EDX and TEM. Furthermore, nanocomposite showed good catalytic behavior in Betti reaction- synthesis of 1-(α-aminoalkyl)-2-naphthols. The favorable properties of colloidal nanocomposite were attributed to the stable and well distribution Au NPs on rMGO.

A pH optical and fluorescent sensor based on rhodamine modified on activated cellulose paper

A rhodamine‐based colorimetric and fluorescent pH chemosensor (RhA) was designed and synthesized via a coupling reaction between rhodamine ethylenediamine and succinic anhydride. RhA showed excellent pH response in aqueous solutions. In addition, common cations (Na+, K+, Ag+, Mg2+, Ca2+, Pb2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Al3+, Cr3+, Fe3+, Au3+, Pt2+, and Ru2+) did not interfere with the pH response. As it has the potential to be used as a portable pH sensor, RhA was immobilized on activated cellulose paper using N,N'‐dicyclohexylcarbodiimide (DCC) and N,N'‐dimethylpyridin‐4‐amine (DMAP) as the coupling reagent to obtain a composite pH sensor (CP‐RhA). CP‐RhA was characterized by ATR‐FTIR, UV–vis, and fluorescence spectroscopy, and by scanning electron microscopy (SEM). CP‐RhA showed a rapid response in the pH range 1–8 through color and fluorescence changes. DFT calculations showed a blue‐shifted spectrum in the protonated form compared to the neutral form. Moreover, the pH sensor paper could be reused by dipping in NaOH. Thus, our work demonstrates the potential of the rhodamine dye composite for visualizing pH changes in real systems.