Physico-Chemical Principles of Color Chemistry

Peters, A. T.; Freeman, Harold S.

doi:10.1007/978-94-009-0091-2

Cited by 17 publications

(4 citation statements)

References 39 publications

(44 reference statements)

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“…Unsurprisingly, Table 6 shows enhanced DOX LCs upon covalent crosslinking. Moreover, the tested NPs were able to load greater amounts of DOX compared to MB (Table 5) probably because MB is of higher water solubility [43.6 and 20 mg/ml for MB (Peters and Freeman, 1996) and DOX, respectively] leading to more MB loss during post loading processing. DOX release profiles from CP-PPA, CPS-HMP, CROSS-CP-PPA, and CROSS-CPS-HMP NPs are shown in Figures 7A,B.…”

Section: Dox Nps Loading Release Profiles and Cytotoxicitiesmentioning

confidence: 99%

Stable Chitosan-Based Nanoparticles Using Polyphosphoric Acid or Hexametaphosphate for Tandem Ionotropic/Covalent Crosslinking and Subsequent Investigation as Novel Vehicles for Drug Delivery

Saeed

Dmour

Taha

2020

Front. Bioeng. Biotechnol.

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Chitosan nanoparticles (NPs) are widely studied as vehicles for drug, protein, and gene delivery. However, lack of sufficient stability, particularly under physiological conditions, render chitosan NPs of limited pharmaceutical utility. The aim of this study is to produce stable chitosan NPs suitable for drug delivery applications. Chitosan was first grafted to phthalic or phenylsuccinic acids. Subsequently, polyphosphoric acid (PPA), hexametaphosphate (HMP), or tripolyphosphate (TPP) were used to achieve tandem ionotropic/covalently crosslinked chitosan NPs in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC). Thermal and infrared traits confirmed phosphoramide bonds formation tying chitosan with the polyphosphate crosslinkers within NPs matrices. DLS and TEM size analysis indicated spherical NPs with size range of 120 to 350 nm. The generated NPs exhibited excellent stabilities under harsh pH, CaCl 2, and 10% FBS conditions. Interestingly, DLS, NPs stability and infrared data suggest HMP to reside within NPs cores, while TPP and PPA to act mainly as NPs surface crosslinkers. Drug loading and release studies using methylene blue (MB) and doxorubicin (DOX) drug models showed covalent PPA-and HMP-based NPs to have superior loading capacities compared to NPs based on unmodified chitosan, generated by ionotropic crosslinking only or covalently crosslinked by TPP. Doxorubicinloaded NPs were of superior cytotoxic properties against MCF-7 cells compared to free doxorubicin. Specifically, DOX-loaded chitosan-phthalate polyphosphoric acidcrosslinked NPs exhibited 10-folds cytotoxicity enhancement compared to free DOX. The use of PPA and HMP to produce covalently-stabilized chitosan NPs is completely novel.

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Section: Dox Nps Loading Release Profiles and Cytotoxicitiesmentioning

confidence: 99%

Stable Chitosan-Based Nanoparticles Using Polyphosphoric Acid or Hexametaphosphate for Tandem Ionotropic/Covalent Crosslinking and Subsequent Investigation as Novel Vehicles for Drug Delivery

Saeed

Dmour

Taha

2020

Front. Bioeng. Biotechnol.

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“…From all mentioned, another factor that could be influencing such high colorant yields is the use of EE impellers. One hypothesis is that the high molecular oxygen dissolved in the fermented broth may create an oxidative stress environment, as water-soluble oxygen can attack the colorants’ chromophore . In this way, the colorants’ stability under an oxidative stress environment should be further researched in the future.…”

Section: Resultsmentioning

confidence: 99%

“…One hypothesis is that the high molecular oxygen dissolved in the fermented broth may create an oxidative stress environment, as water-soluble oxygen can attack the colorants' chromophore. 47 In this way, the colorants' stability under an oxidative stress environment should be further researched in the future. The greater oxygen supply and better mixing influences the colorant biosynthesis.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Improving the Environmental Sustainability of Polyketides Colorants Production by Talaromyces Strain through Better Hydrodynamic Design in Bioreactors

Oliveira

Zapata-Boada

Silva

et al. 2022

ACS Sustainable Chem. Eng.

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One important step toward the commercialization of microbial-derived colorants is the reproducibility of the cultivation stage in bench-scale bioreactors as well as improving the hydrodynamic design in bioreactors. Aiming to address these technical barriers, Talaromyces amestolkiae was cultivated in a 4 L stirred-tank bioreactor using two types of impellers (Rushton turbine (RT) and Elephant ear (EE) impellers) and aeration modes (cascading and constant airflow) to assess their effects on red colorant production. The results showed that EE under constant airflow (4.0 L min–1) promoted the maximum red colorant formation (28.7 UA500nm), thus improving the reproducibility of the process. The volumetric oxygen transfer coefficient of culture broth was correlated to cell morphology, which was a result of the impeller geometry of EE through the shear conditions impacting the fungi cells. The hairy pellet morphology favored nutrient and oxygen uptake and allowed an improvement in the colorant’s synthesis. Life cycle assessment was also carried out to identify opportunities for improving the best process design from an environmental sustainability perspective. For example, the total climate change and primary energy demand were estimated at 31.11 kg CO2 eq./g red colorant and 830.7 MJ/g red colorant, respectively, with the cultivation stage contributing with 65 and 63% of these impacts. The electricity consumption was identified as the main hotspot in this stage, a trend that was observed across all other impact categories. This can be improved by optimizing cultivation lengths combined with the use of low carbon electricity sources. These findings ensure a step forward toward the scaling-up at the industrial scale of the T. amestolkiae cultivation for the production of bio-based colorants in an environmentally sustainable way.

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“…were calculated using fluorescein ( fluorescein = 0.91 in ethanol) [18] as a reference standard using the comparative method. 1 H NMR spectra were recorded on VXR 400-MHz instrument using TMS as an internal standard and DMSO as the solvent. Purification of all the compounds was generally achieved by recrystallization.…”

Section: Materials and Equipmentsmentioning

confidence: 99%

Pigment Yellow 101 analogs from 3-(1,3-benzothiazol-2-yl)-2-hydroxynaphthalene-1-carbaldehyde – Synthesis and characterization

2015

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Physico-Chemical Principles of Color Chemistry

Cited by 17 publications

References 39 publications

Stable Chitosan-Based Nanoparticles Using Polyphosphoric Acid or Hexametaphosphate for Tandem Ionotropic/Covalent Crosslinking and Subsequent Investigation as Novel Vehicles for Drug Delivery

Stable Chitosan-Based Nanoparticles Using Polyphosphoric Acid or Hexametaphosphate for Tandem Ionotropic/Covalent Crosslinking and Subsequent Investigation as Novel Vehicles for Drug Delivery

Improving the Environmental Sustainability of Polyketides Colorants Production by Talaromyces Strain through Better Hydrodynamic Design in Bioreactors

Pigment Yellow 101 analogs from 3-(1,3-benzothiazol-2-yl)-2-hydroxynaphthalene-1-carbaldehyde – Synthesis and characterization

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