High-speed Vibration Milling Research Articles

Water Solubilization and Guest Molecule-Induced Fluorescence Changes of Porous Host Molecules via Complexing with Polysaccharide or Polypeptide.

To detect small aromatic molecules in water, we prepared functional host molecules based on water-soluble N,N'-bis(2-aminobenzophenone)-1,4,5,8-naphthalenetetracarboxylic diimide (1) and a solubilizing agent using a high-speed vibration milling apparatus. The fluorescence response of host 1-solubilizing agent complexes before and after extraction of small aromatic guest molecules was large and the fluorescence maxima were dependent on the small aromatic guest molecules.

"On-off" Switching of Functional Guest Molecules via Exchange of Natural Product Solubilizing Agents.

For the development of delivery systems, the solubilization of hydrophobic guest molecules in water is an important yet challenging task. This can be achieved by preparing stable aqueous solutions with a high concentration of guest molecules using a natural product as a solubilizing agent and a mechanochemical high-speed vibration milling apparatus as a solubilizing method. Various solubilizing agent-guest molecule complexes can be obtained via the exchange between solubilizing agents, which enables the "on-off" switching of the properties of functional guest molecules, such as fluorescence intensity, and photodynamic activity. In the exchange method, guest molecules can transfer into cell membranes such as lysosomes and exosomes. Therefore, the exchange method of the solubilizing agents not only creates novel solubilizing agent-guest molecule complexes but also is applied to drug delivery systems.

Development of a Water-Dispersible Supramolecular Complex of Polyphenol with Polypeptides for Attenuation of the Allergic Response using a Mechanochemical Strategy.

The prevalence of allergic disorders has increased worldwide in recent decades. Polyphenols, including resveratrol and curcumin, are posited to have potential as therapeutic agents for allergy; however, their use has been limited by poor water solubility. Accordingly, a highly concentrated, water dispersible, supramolecular complexes of polyphenols with polypeptides (poly-L-lysine, poly-γ-glutamic acid) and gelatin using high-speed vibration milling are developed. The complex exhibits resistance to photobleaching and thermal radiation. Treatment of a rat basophilic leukemia cell line (RBL-2H3) with polypeptide complexes containing resveratrol is suppressed allergic responses in vitro. Moreover, aerosolized administration of polypeptide complexes demonstrates excellent bioavailability and inhibition of immediate hypersensitivity reactions in ear tissue in vivo. Furthermore, the method avoids the use of organic solvent and therefore reduces undesirable biological responses.

Fluorescence Turn-on of Tetraphenylethylene Derivative by Transfer from Cyclodextrin to Liposomes, HeLa Cells, and E. coli.

Herein, trimethyl-β-cyclodextrin (TMe-β-CDx) and γ-cyclodextrin (γ-CDx) could dissolve a tetraphenylethylene derivative (TPE-OH4 ) in water through high-speed vibration milling. The fluorescence intensity of the TMe-β-CDx-TPE-OH4 complex was much higher than that of the γ-CDx-TPE-OH4 complex, as the rotation of the central C=C double bond of TPE-OH4 after photoactivation was inhibited in a smaller TMe-β-CDx cavity in comparison with the γ-CDx cavity. In contrast, the fluorescence intensity of the γ-CDx-TPE-OH4 complex was very weak; nevertheless, it increased after the addition of liposomes due to the transfer of TPE-OH4 from the γ-CDx cavity to the lipid membrane as a "turn-on" phenomenon. Furthermore, to apply temperature sensor, it was demonstrated that the fluorescence intensity in the liposomes depended on the phase-transition temperature. By using the fluorescence turn-on phenomenon, TPE-OH4 could detect the presence of HeLa cells and E. coli by fluorescence.

C60 intercalating Ti3C2T MXenes assisted by γ-cyclodextrin for electromagnetic interference shielding films with high stability

Ti3C2Tx MXenes with excellent metallic conductivity and flexibility have shown a promising prospect as electromagnetic interference (EMI) shielding materials. Ultrathin, hierarchical hybrid films were fabricated by using C60 intercalating Ti3C2Tx MXenes with the assistance of water-soluble γ-cyclodextrin (CD). The C60/CD complex was obtained by high-speed vibration milling using hydrophilic CD as dispersing agent. After thermal annealing treatment, the obtained hybrid film exhibited excellent EMI shielding (53.52±0.43 dB), hydrophobicity (water contact angle: 93.7°) and mechanical stability (over 0.9 million bending times). Taking advantage of the antioxidant of C60, the chemical durability of Ti3C2Tx MXenes based hybrid films was also improved as expected. These results indicate that the well-designed hierarchical hybrid films with the intercalation of C60 have promising potential for high-performance EMI shielding applications.

Formulation of water-dispersible hydrophobic compound nanocomplexes with polypeptides via a supramolecular approach using a high-speed vibration milling technique.

Polypeptides were used to solubilize functional hydrophobic molecules via a high-speed vibrational milling method. Poly-l-lysine and poly-γ-glutamic acid, which are polypeptides, were able to prepare more highly concentrated water-dispersible complexes of hydrophobic compounds, including fullerenes, organic dyes, and porphyrin derivatives, than conventional water solubilizers, such as cyclodextrins and pullulan. In addition, the polypeptide systems endowed the complexes with long-term stability and resistance against thermal stress, which is advantageous for industrial applications. Furthermore, complexes of polypeptides and porphyrin derivatives showed a photodynamic activity against cancer cells, and the current system improved the dispersibility and storability of guest molecules without compromising their functionality.

Amphiphilic γ-cyclodextrin–fullerene complexes with photodynamic activity

High-speed vibration milling of a mixture of lipophilic γ-cyclodextrin (γ-CD), hydrophilic γ-CD and fullerene or functionalization of preformed γ-CD–fullerene complexes afforded amphiphilic γ-CD–fullerene complexes with high photodynamic activity.

Mechanism toward Turn‐on of Polysaccharide‐Porphyrin Complexes for Fluorescence Probes and Photosensitizers in Photodynamic Therapy in Living Cells

β-(1,3-1,6)-D-Glucan, λ-carrageenan, tamarind gum, and pullulan can dissolve various porphyrin derivatives via the formation of complexes in water using a high-speed vibration milling method. The aqueous solutions of the resulting complexes exhibit long-term stability. Despite the adverse effects of the self-quenching process, notable fluorescence and improved photodynamic activity of the polysaccharide-complexed porphyrin derivatives were observed in the presence of liposomes, micelles, cyclodextrins, and HeLa cells. It was noted that the type of porphyrins was more important than the type of polysaccharides present in the complex. Porphyrin self-aggregates were monodispersed in the lipid membranes of the liposomes and lysosomes. The polysaccharide-complexed porphyrin derivatives showed increased photodynamic activity toward HeLa cells under photoirradiation between 610 and 740 nm.

Solubilization of Tetrahydroxyphenylchlorin in Water and Improved Photodynamic Activity after Complexation with Cyclic Oligo- and Polysaccharides.

Chlorins with phenol units were dissolved in water via complexation with the solubilizing agents trimethyl-β-cyclodextrin and λ-carrageenan using a high-speed vibration milling technique. The photodynamic activities of the trimethyl-β-cyclodextrin (TMeβCD) and λ-carrageenan complexes were similar to that of Photofrin. However, the λ-carrageenan chlorin complexes were more stable in aqueous solutions than the TMeβCD-chlorin complexes. Thus, λ-carrageenan-complexed chlorin would be more suitable as a photosensitizer.

Mechanism and experiment of high-speed ultrasonic elliptical vibration milling of thin-walled titanium alloy parts

Mechanism and experiment of high-speed ultrasonic elliptical vibration milling of thin-walled titanium alloy parts

Mechanochemical Synthesis and Properties of Boronic Ester Cage Compounds

Background: In the past decades, mechanochemical organic synthesis has become an attractive technique for solvent-free synthesis, which avoids the usage of harmful solvents and production of toxic wastes. This method has been utilized to promote the efficient formation of carbon-carbon and carbon-heteroatom bonds. The mechanochemical synthesis of macrocyclic molecules, rotaxanes and covalent organic frameworks has been reported recently. However, the mechanochemical construction of purely organic cage compounds is scanty and challenging. Objective: The primary objective of this study was to synthesize boronic ester cage compounds under high-speed vibration milling conditions and investigate their properties. Method: A mixture of triboronic acids 3 (0.04 mmol) and pentaerythritol (0.06 mmol) was vigorously shaken under high-speed vibration milling (HSVM) conditions at 58 Hz for 40 min. The resulting solid was dissolved in chloroform (5 mL) and then filtered. Cage compounds 4 were obtained by removal of the solvent, and dried under vacuum at 100 degrees C for 12 h. Cage compounds 4 were subjected to thermogravimetric analysis and chemical stability experiments. Result: Boronic ester cage compounds 4 were synthesized in nearly quantitative yields under high-speed vibration milling conditions. Furthermore, thermogravimetric analysis and chemical stability experiments showed that cage compounds 4 possessed high thermal stability (T-dec up to 320 degrees C) and good chemical stability in aqueous media. Conclusion: We have described an efficient solvent-free synthesis of boronic ester cage compounds 4 under the HSVM conditions. Furthermore, cage compounds 4 possessed high thermal stability and good chemical stability in aqueous media.

Green Synthesis of Pyrrole Derivatives

Background: Pyrroles are organic cyclic compounds with an extensive and fascinating chemistry. These compounds have a wide structural variety and they are an important basis in technological development as they can be used as drugs, dyes, catalysts, pesticides, etc. Therefore, the production of these heterocyclic compounds by efficient clean methodologies is a great achievement in contemporary chemistry. In this paper, we show recent green procedures in the synthesis of pyrrole derivatives such as Hantzsch, Knorr and Paal- Knorr syntheses, as well as new eco-friendly synthetic procedures with high efficiency and low environmental impact. Objective: This work focusses on the recent advances in the pyrrole synthesis using clean techniques like ultrasound (US), microwaves (MW), high speed vibration milling (HSVM), catalysts use, solvent replace and other methodologies applied to common reactions to obtain the pyrrole core which follow the green chemistry principles. Conclusion: The main challenge of Green Chemistry is to gradually eliminate the generation of hazardous or harmful materials or replace them with less toxic and safer ones. However, this process must be driven by scientific developments. Its application in the synthesis of heterocyclic compounds such as pyrrole derivatives involves multiple economic and social benefits due to the biological importance of these compounds and their direct impact on the pharmaceutical industry. Although many processes are still under investigation using novel methodologies of green activation such as microwaves, ultrasound and HSVM, as well as synthetic processes in continuous flow and processes at room temperature, promising results such as cost and waste reduction and greater efficiency are achieved.

Liquid-Assisted One-Pot Mechanosynthesis and Properties of Neutral Donor-Acceptor [2]Rotaxanes.

An efficient liquid-assisted one-pot two-step synthesis of neutral donor-acceptor [2]rotaxanes has been successfully realized under high-speed vibration milling conditions, by taking advantage of the donor-acceptor interaction between the electron-rich naphthalene unit of a macrocyclic polyether and the electron-deficient naphthalene diimide unit of a thread component for the threading process and click reaction as the stoppering process. The present method provides a powerful, fast, and environmentally benign alternative to traditional solvent-based approaches due to its notable advantages such as very small amount of solvent, no external heating, shorter reaction time, and higher yield. In addition, the charge-transfer interaction and electrochemically induced shuttling of the synthesized neutral donor-acceptor [2]rotaxanes have been demonstrated.

ChemInform Abstract: Three‐Component Synthesis of Pyrrole‐Related Nitrogen Heterocycles by a Hantzsch‐Type Process: Comparison Between Conventional and High‐Speed Vibration Milling Conditions.

The use of solvent-free, high-speed vibration milling conditions has allowed the development of a one-pot telescoped process for the synthesis of pyrroles starting from ketones, primary amines, and β-dicarbonyl compounds and comprising an initial α-iodination followed by an in situ three-component Hantzsch-type reaction. This method was compared with a solution-based protocol from α-iodoketones, primary amines, and β-dicarbonyl compounds. Although both protocols were far more general than previous Hantzsch-type pyrrole syntheses, the mechanochemical method was superior in that it afforded considerably higher yields in spite of comprising an additional step. The stereochemical integrity of the pyrroles obtained from chiral α-aminoesters was maintained. This solvent-free method was also used for the efficient preparation of ter- and quater-aryl/heteroaryl frameworks containing two pyrrole units and a variety of fused pyrrole systems, including benzo[g]indoles, indeno[1,2-b]pyrroles, indoles, and homoindoles.

Improved isolation procedure for shikonin from the root of the Chinese medicinal plant Lithospermum erythrorhizon and its solubilization with cyclodextrins

In this study, we improved the method for the isolation and purification of the bioactive compound shikonin from the dried root of the traditional Chinese medicinal plant Lithospermum erythrorhizon without a tedious chromatographic separation. Furthermore, we also attempted the solubilization of shikonin in water with cyclodextrins (CDs) using a solid phase “high-speed vibration milling”. Among the various CDs, sulfobutylether-β-CD (SBEβ-CD) showed a highest solubilizing ability and 52.5% of shikonin was solubilized with equimolar amount of SBEβ-CD. In addition, the SBEβ-CD·shikonin complex showed higher apoptogenic activity than that of the same concentration of free shikonin against murine primary peritoneal macrophages. These results indicate that SBEβ-CD is a suitable excipient for clinical application of shikonin.

ChemInform Abstract: Synthesis of Pyrroles from β‐Enamines and Nitroolefins Catalyzed by I2 under High‐Speed Vibration Milling (HSVM).

AbstractPolysubstituted pyrroles are synthesized from β‐enamines and nitroolefins in the presence of iodine as the catalyst using a high‐speed vibration milling (HSVM) technique under neat conditions.

Synthesis of Pyrroles from β-Enamines and Nitroolefins Catalyzed by I2 under High-speed Vibration Milling (HSVM)

Abstract A solvent-free reaction, using a high-speed vibration milling (HSVM) technique, has been developed for the synthesis of polysubstituted pyrroles from β-enamines and nitroolefins as the raw materials, by using iodine as the catalyst. The influences of the vibration frequency and the reaction time were investigated and a series of 2,3,4-polysubstituted pyrroles were obtained in good yields at short reaction times (20 min) under the HSVM condition. It is an efficient, simple, and moderate approach for synthesizing polysubstituted pyrroles under the HSVM conditions.

A facile high-speed vibration milling method to mass production of water-dispersible silicon quantum dots for long-term cell imaging

A facile HSVM method has been developed for mass production of water-dispersible SiQDs for long-term cell imaging.

Solvent-Free synthesis of 2-Aminothiophene-3-Carbonitrile Derivatives Using High-Speed Vibration Milling

The solvent-free synthesis of 2-aminothiophene-3-carbonitrile derivatives by high-speed vibration milling using the inexpensive and environmentally friendly Et2NH as a catalyst was studied. The reaction conditions were optimised and the derivatives were obtained in good yield. This method has advantages in terms of short reaction time and facile conditions.

Concise synthesis of atorvastatin lactone under high-speed vibration milling conditions

A Hantzsch-type multicomponent reaction under high-speed vibration milling conditions followed by acid treatment afforded atorvastatin lactone in 38% overall yield.