Active Amino Research Articles

Generation of Active Amino Groups on the Surface of a Polyethylene Terephthalate Film and Their Quantitative Evaluation

Generation of Active Amino Groups on the Surface of a Polyethylene Terephthalate Film and Their Quantitative Evaluation

DNA Molecular Glue Assisted Bacterial Conjugative Transfer.

Bacterial conjugation, a commonly used method to horizontally transfer functional genes from donor to recipient strains, plays an important role in the genetic manipulation of bacteria for basic research and industrial production. Successful conjugation depends on the donor-recipient cell recognition and a tight mating junction formation. However, the efficiency of conjugative transfer is usually very low. In this work, we developed a new technique that employed DNA molecule "glue" to increase the match frequency and the interaction stability between the donor and recipient cells. We used two E. coli strains, ETZ and BL21, as a model system, and modified them with the complementary ssDNA oligonucleotides by click chemistry. The conjugation efficiency of the modified bacteria was improved more than 4 times from 10 %-46 %. This technique is simple and generalizable as it only relies on the active amino groups on the bacterial surface. It is expected to have broad applications in constructing engineered bacteria.

A One-Nano MOF-Two-Functions Strategy Toward Self-healing, Anti-inflammatory, and Antibacterial Hydrogels for Infected Wound Repair

Porous metal–organic frameworks (MOF)-based hydrogels have recently attracted wide attention in sensing, catalysis, water treatment, and biomedicine. Yet, limited by challenges of insufficient stability, inordinate metal-ion leakage, and weak wound healing efficacy, the design of MOF-based hydrogel dressings for infected wounds has been rarely explored. Here, we propose a “one-nano MOF-two-functions” strategy to demonstrate the molecular engineering of a chemically stable nano MOF, which acts as both a carrier and a dynamic cross-linker, to fabricate functional composite hydrogels. The active amino groups of the MOF are employed to create dynamic networks with aldehyde-bearing alginate, ensuring excellent compatibility of the MOF with the polymer matrix and imparting effective self-healing properties to the resulting hydrogels. Simultaneously, two active ingredients, Cu nanoparticles (NPs) and curcumin, can be loaded into the nano MOF, achieving synergistic anti-inflammatory and antibacterial effects. Assisted by the mechanical stability and drug co-delivery in an infected full-thickness skin model, the MOF-based hydrogel can reduce the bacterial load on the wound by ∼103 times, and promote collagen deposition and angiogenesis by ∼1.5 and ∼3 times, compared with the control group. The “one-nano MOF-two-functions” design exhibits significant potential for high-performance infected wound dressings.

Isoreticular Metal-Organic Framework-3 (IRMOF-3): From Experimental Preparation, Functionalized Modification to Practical Applications.

Isoreticular metal-organic framework-3 (IRMOF-3), a porous coordination polymer, is an MOF material with the characteristics of a large specific surface area and adjustable pore size. Due to the existence of the active amino group (-NH2) on the organic ligand, IRMOF-3 has more extensive research and application potential. Herein, the main preparation methods of IRMOF-3 in existing research were compared and discussed first. Second, we classified and summarized the functionalization modification of IRMOF-3 based on different reaction mechanisms. In addition, the expanded research and progress of IRMOF-3 and their derivatives in catalysis, hydrogen storage, material adsorption and separation, carrier materials, and fluorescence detection were discussed from an application perspective. Moreover, the industrialization prospect of IRMOF-3 and the pressing problems in its practical application were analyzed and prospected. This review is expected to provide a reference for the design and application of more new nanomaterials based on IRMOF-3 to develop more advanced functional materials in industrial production and engineering applications.

Modification of ionic liquid and lactoferrin-based small molecules as potential therapeutics against SARS-CoV-2: Molecular docking disclosed the predictable results

Ionic liquid MIE-NH2 displays a new role in the development of modification of glycoproteins of lactoferrin through a reductive amination mechanism to synthesize versatile pharmaceuticals. This work introduces a new strategy of modification of lactoferrin by using methyl imidazolium N-ethylamine MIE-NH2, this ionic liquid linked to N-glycans in lactoferrin derivatives in simple method. The modification of lactoferrin with MIE-NH2 as a novel small molecule (SM-IL-Lf) contains active amino groups is confirmed by UPLC/ESI-QTOF and MALDI-TOF mass spectrometry. Molecular docking disclosed the bioactivity of modifying glycoproteins - small IL-Lf-molecules by elucidating its interactions with the inspected targets. This providing of small molecules IL-Lf released a wide display with different functions as significantly important drug candidates inhibiting the targets of main protease (Mpro), RNA dependent RNA polymerase (RdRp), transmembrane protease serine 2 (TMPRSS2), and Papain-like protease (PLpro). The probability of the modeling N-glycans from lactoferrin modified and designed as small IL-Lf-molecules to inhibit any of these targets was investigated to find out its potency inhibitor of SARS-CoV-2.

Robust mechanical strength and high colorfastness of amorphous photonic crystals on fabrics with durable antibacterial and anti-static properties

The technique of utilizing structural color dyeing presents a sustainable and energy-conserving approach to textile dyeing. However, the coating with structural coloration always exhibited cracks and inadequate colorfastness attributed to the presence of capillary tension. In this study, we employed a hydrophilic silane called 3-aminopropyltriethoxysilane (KH550) to chemically modify the fabric. This method endowed the fabric with reactive amino groups, thereby augmenting the interfacial bonding strength between polydopamine (PDA)@SiO2@Ag+/Ag NPs and the fabric substrate through metal coordination and covalent bonds. Additionally, by utilizing catechol complexation, we successfully loaded Ag ions onto the PDA coating of composite microspheres. These Ag ions acted as linkers during self-assembly of microspheres. The active amino groups on the surface of chemically modified cotton fabric reacted with PDA at a specific temperature, resulting in the formation of robust covalent bonds simultaneously. The resulting fabric demonstrated excellent water resistance as well as efficient antibacterial and anti-static properties, which were confirmed through various mechanical tests such as washing, folding, and rubbing experiments. This research presents an innovative approach for creating durable structural colored fabrics with multifunctional properties based on metal coordination and covalent bonds that can be effectively applied in textile printing and dyeing.

The Heptazine-Based Materials through Intrinsically Modification for the Cycloaddition of CO2 and Bisepoxides.

For the efficient utilization of CO2 into valuable product, the attractive carbon nitride catalysts have been widely studied. In this work, heptazine-related materials with varying degree of polymerization were designed by an intrinsically modification strategy and employed in the cycloaddition of CO2 with the bisepoxide 1, 4-butanediol diglycidyl ether (BDODGE). We initially figured out that the sample prepared at 450 °C contained more melem hydrate, exhibiting the best performance. The epoxides conversion and corresponding cyclic carbonates selectivity could achieve 93.1 % and 99.3 % at 140 °C for 20 h without any cocatalyst and solvent, respectively. Results of the catalytic tests suggested that the high catalytic activity was dependent on big size porous structure and the synergetic effect of active amino groups and -OH groups. The role of water in maintaining the specific structure and providing active site has been proved. Moreover, the CN-450-W catalyst exhibited outstanding recycling stability. And finally, a plausible reaction mechanism was proposed.

Synchronous surface reconstruction and grain boundary healing toward efficient and stable inverted CsPbI3 perovskite solar cells

Cesium lead iodide (CsPbI3) perovskite has gained considerable attentions due to its unique photoelectric properties. However, numerous defects are inevitably existed on the surface and grain boundaries (GBs) of CsPbI3 resulting from the rapid crystallization and growth progress. Herein, different from the traditional ammonium salt treatment mechanism, we propose a facile strategy to synchronously achieve surface reconstruction and grain boundary healing by using 1,3-propylene diamine (PDA) post-treatment on CsPbI3 film. It is discovered that the PDA with suitable concentration can preferentially invade the defect sites of surface and GBs of CsPbI3 film, thereby break the soft perovskite structure in the shallow surface. With further low temperature annealing treatment, the broken CsPbI3 surface would undergo rapid secondary crystal growth to acquire smoother and blurred morphology with reduced GBs and pinholes, primarily derived from the strong interaction between the highly active amino groups of liquid PDA and Pb of perovskite. Meanwhile, the residual PDA molecules mainly anchor at the surface and GBs, and thus connect neighboring perovskite grains, coordinate uncoordinated sites to effectively passivate defects, and also resist the external invasions. Consequently, the inverted PDA-based CsPbI3 device yields a champion PCE of 20.02% with significantly improved long-term storage stability and operational stability.

Application of Chitosan-Based Hydrogel in Promoting Wound Healing: A Review.

Chitosan is a linear polyelectrolyte with active hydroxyl and amino groups that can be made into chitosan-based hydrogels by different cross-linking methods. Chitosan-based hydrogels also have a three-dimensional network of hydrogels, which can accommodate a large number of aqueous solvents and biofluids. CS, as an ideal drug-carrying material, can effectively encapsulate and protect drugs and has the advantages of being nontoxic, biocompatible, and biodegradable. These advantages make it an ideal material for the preparation of functional hydrogels that can act as wound dressings for skin injuries. This review reports the role of chitosan-based hydrogels in promoting skin repair in the context of the mechanisms involved in skin injury repair. Chitosan-based hydrogels were found to promote skin repair at different process stages. Various functional chitosan-based hydrogels are also discussed.

Efficient removal of sodium dodecyl benzene sulfonate employing chitosan-modified waste floral foam as adsorbent

The wide application of surfactants has brought about severe contamination to environment, especially, in aqueous media. In this connection, efficient removal of surfactant residues in waters is essential. In the present work, a commonly used surfactant, sodium dodecyl benzene sulfonate (SDBS) was employed as a model surfactant for removal studies. A new adsorbent based on waste floral foam (FF) was prepared and employed to remove SDBS in various waters. Phenol formaldehyde resin-based waste FF was firstly activated with alkali aqueous, and then modified with chitosan (CS) to introduce active amino groups on the framework of FF to obtain the adsorbent based on CS-modified FF (CS@FF). Under the optimized synthesized conditions, the obtained adsorbent displayed satisfactory removal performance towards SDBS by means of multipoint and multitype interactions, 93.3 % SDBS was removed within 30 min. The adsorption behavior of CS@FF towards SDBS well fitted the pseudo-second order kinetic model and Langmuir adsorption model. In addition, increase of temperature favored the removal of SDBS. After the optimization of removal parameters, the CS@FF was used to remove SDBS in actual waters, and the achieved removal rates were obviously higher than that achieved on unmodified FF. The present study not only provides a cost-effective adsorbent for the removal of surfactants, but also opens up a feasible route for reutilization of discarded FF.

A Photocurable Polysaccharide-Based Hydrogel Delivery of Polydeoxyribonucleotide-Loaded Vectors for Wound Treatment.

The wounds caused by war, accidents, and diseases require timely and effective treatment. Polysaccharides, as natural macromolecules, have good biocompatibility and unique functions, and are excellent substrates for constructing new wound dressings. Short-chain chitosan (SCS) has good water solubility and, importantly, retains a large number of active amino groups. We first introduce double bonds to SCS. This chitosan derivative can be entangled with sodium alginate (SA) through electrostatic interaction. The flowing sol can be applied to a wound with an irregular shape. Under the initiation of a photoinitiator, the internal double bonds are broken and cross-linked to form a gel. The prepared hydrogel wound dressing exhibited good antibacterial properties and can provide a microenvironment conducive to wound repair. A polydeoxyribonucleotide (PDRN) has been proven to have encouraging therapeutic effects for wound healing. PDRN can be condensed by branched polyethylenimine (PEI) to form a nucleic acid delivery system, which can be efficiently uptaken by cells. The cooperation of hydrogel and nucleic-acid-based therapy presented good results in a mouse full-thickness skin wound model.

Synthesis of novel rimantadine and adamantane-1-carboxylic acid derivatives with 1,2-azole fragments

Various adamantane derivatives were obtained by the condensation of rimantadine with substituted hydroxy-benzaldehydes, esters and ethers based on them, as well as 1,2-azole-3-carbaldehydes, followed by reduction. Further acylation of derivatives with active amino and hydroxy groups yielded compounds containing two 1,2-azole fragments in one molecule.

Photocatalytic and structure evaluation of g-C3N4/carbon microspheres and melam/dimelem intermediates under white LED and UVA-Vis irradiation

Despite the polymeric metal-free graphitic carbon nitride (g-C3N4) has been extensively studied for photodegradation, intermediate oligomers (melam/dimelem) can be generated during the polymerization process and it is a subject matter. The melem compounds feature active amino groups (-NH2) partially linked to one another, facilitating intermolecular reactions and alteration of the compound's structure. This study evaluated the synergic effect of carbon matrix on the physicochemical and electronic characteristics of g-C3N4 (CN) and melam/dimelem intermediates compounds by synthesis in situ of chitosan and CN precursors. The g-C3N4 were obtained using urea (U) and melamine (M), denoted as CN/U and CN/M, and the carbon microspheres, denoted as CN/CU and CN/CM. The characterizations suggest C–N sp2-hybridized bonds between the carbon ring from chitosan and the melam/dimelem unit, which may be highly activated either in the visible or UVA regions. An increase of 16% in photocatalytic efficiency for CN/CM material was observed by incorporating chitosan in the g-C3N4 using withe LED light. The carbon microspheres interact synergistically with the bulk g-C3N4 to form two-dimensional planes in which the charge carriers can move freely along the carbon ring structure. The carbon microspheres are an excellent option to separate the photocatalyst easily from the reaction mixture. Additionally, the photocatalytic degradation mechanism of RhB by carbon microspheres was also proposed.

Modification of disused floral foam with polyethylene diamine for the removal of heavy metal ions

Floral foam (FF) based on phenol formaldehyde resin has been used widely for many years, but it is re-used rarely and the discarded FF is harmful to environment. Therefore, recycling of disused FF is interesting and highly required. In current study, a new strategy for reutilization of disused FF was proposed. FF which had been treated with NaOH solution was dipped in polyethyleneimine (PEI) solution to anchor active amino groups on the framework of FF, and then glutaraldehyde was employed to cross-link the anchored PEI to obtain a novel adsorbent based on disused FF (PEI@FF). Due to the abundant amino groups, the prepared adsorbent displayed satisfactory chelating ability towards heavy metal ions. Under the optimal synthesis and adsorption conditions, the PEI@FF was applied to remove Cu(II), Cd(II) and Pb(II) in environmental waters, and the removal rates varied from 91.4% to 95.6%, which were much higher than that achieved on unmodified FF (35–43%). Additionally, the PEI@FF exhibited good batch-to-batch preparation repeatability and acceptable number of cyclic utilization. The satisfactory results well evidence the proposed method is practicable for reutilization of discarded FF, and the present study also supplies a new adsorbent for the high efficient removal of heavy metal ions.

Synthesis of hollow molecular imprinting nanoparticles based on polyethylenimine and boronate affinity for selective extraction of ovalbumin

The hollow MCM-48 polyethyleneimine carboxyphenylboronic acid molecularly imprinted polymers (H-MPC@MIPs) were synthesized to efficiently and selectively separate and enrich the ovalbumin (OVA) in egg white samples. Polyethyleneimine contained enough active amino groups to increase the amount of boric acid molecules modified to silica nanoparticles. Meanwhile, the materials were etched to enhance the adsorption effect. The H-MPC@MIPs exhibited a rapid adsorption equilibrium rate (within 30 min) and outstanding adsorption capacity for OVA (1334.1 mg g−1). It possessed a good reusability after 5 cycles. In addition, both the high density and the imprinting action of boric acid were essential for enhancing the identification and binding of OVA. The OVA in egg white samples was successfully selectively enriched using this method.

Bis- and tris-amino-substituted tetraphenylporphyrins. Comparative electrochemistry, film formation and ORR response of the films in alkaline media

The paper analyzes how the structure of porphyrin affects its electrochemical characteristics, film formation process and physicochemical properties of the obtained materials. A comparison of the redox processes of 21H,23H-5,15-bis-(4-aminophenyl)-10,20-di-phenyl porphyrin (Porph I) and 21H,23H-5,10,15-tris-(4-aminophenyl)-20-phenyl porphyrin (Porph II) shows that Porph I is more stable in oxidation and less stable in reduction processes than Porph II. The presence of electrochemically active amino groups in the composition of the porphyrin molecules allows the superoxide-assisted electrochemical deposition method to be applied to successfully form poly-Porph I and poly-Porph II films from dimethyl sulfoxide solutions. Spectral methods confirm that the obtained materials preserve their porphyrin structure. The structure of the initial monomer molecules is demonstrated to affect the film formation and surface morphology of the prepared materials. Oxygen electroreduction in an alkaline medium is shown to have smaller kinetic limitations on poly-Porph II films than that on poly-Porph I ones.

Silver Nanoparticle-Embedded Conductive Hydrogels for Electrochemical Sensing of Hydroquinone.

In this work, a conductive hydrogel was successfully synthesized, taking advantage of the high number density of active amino and hydroxyl groups in carboxymethyl chitosan and sodium carboxymethyl cellulose. These biopolymers were effectively coupled via hydrogen bonding with the nitrogen atoms of the heterocyclic rings of conductive polypyrrole. The inclusion of another biobased polymer, sodium lignosulfonate (LS), was effective to achieve highly efficient adsorption and in-situ reduction of silver ions, leading to silver nanoparticles that were embedded in the hydrogel network and used to further improve the electro-catalytic efficiency of the system. Doping of the system in the pre-gelled state led to hydrogels that could be easily attached to the electrodes. The as-prepared silver nanoparticle-embedded conductive hydrogel electrode exhibited excellent electro-catalytic activity towards hydroquinone (HQ) present in a buffer solution. At the optimum conditions, the oxidation current density peak of HQ was linear over the 0.1-100 μM concentration range, with a detection limit as low as 0.12 μM (signal-to-noise of 3). The relative standard deviation of the anodic peak current intensity was 1.37% for eight different electrodes. After one week of storage in a 0.1 M Tris-HCl buffer solution at 4 °C, the anodic peak current intensity was 93.4% of the initial current intensity. In addition, this sensor showed no interference activity, while the addition of 30 μM CC, RS, or 1 mM of different inorganic ions does not have a significant impact on the test results, enabling HQ quantification in actual water samples.

Energy transfer mechanism of carboxymethyl chitosan-Eu3+/Tb3+ complex materials and application in multicolor LED

Biological macromolecules had been studied as ligands in recent years, which not only give the complexes excellent polymer properties, but also have many advantages such as biodegradability. Carboxymethyl chitosan (CMCh) is excellent biological macromolecular ligand because of its abundant active amino and carboxyl groups, and it can smoothly transfer energy to Ln3+ after coordinating. To further study the energy transfer mechanism of CMCh-Ln3+ complexes, CMCh-Eu3+/Tb3+ complexes with different Eu3+/Tb3+ ratios were prepared by using CMCh as a ligand. The morphology, structure, and properties of CMCh-Eu3+/Tb3+ were characterized and analyzed by infrared spectroscopy, XPS, TG and Judd-Ofelt theory, thus the chemical structure of CMCh-Eu3+/Tb3+ was determined. The mechanism of energy transfer was explained in detail, also the Förster resonance transfer model is confirmed, and the hypothesis of energy transfer back was verified by the characterization and calculation methods of fluorescence spectra, UV spectra, phosphorescence spectra and fluorescence lifetime. Finally, CMCh-Eu3+/Tb3+ with different molar ratios were used to prepare a series of multicolor LED lamps, and it extends the application range of biological macromolecules as ligands.

Application of Microscopic Highly Hydrophilic Silica-Based Nanocomposites with High Surface Exposure in the Efficient Identification of Intact N-Glycopeptides.

Glycosylation of proteins regulates the life activities of organisms, while abnormalities of glycosylation sites and glycan structures occur in various serious diseases such as cancer. A separation and enrichment procedure is necessary to realize the analysis of the glycoproteins/peptides by mass spectrometry, for which the surface hydrophilicity of the material is an important factor for the separation and enrichment performance. In the present work, under the premise of an obvious increase of the surface silicon exposure (79.6%), the amount of surface polar silanol is remarkably generated accompanying the introduction of the active amino groups on the surface of silica. The microscopic hydrophilicity, which is determined with water physical-adsorption measurements and can directly reflect the interaction of water molecules and the intrinsic surface of the material, maximally increases by 44%. This microscopically highly hydrophilic material shows excellent enrichment ability for glycopeptides, such as extremely low detection limits (0.01 fmol μL-1), remarkable selectivity (1:8000), and size exclusion effects (1:8000). A total of 677 quantifiable intact N-glycopeptides were identified from the serum of patients with cervical cancer, and the glycosylation site and glycan structure were analyzed in depth, indicating that this novel material can show a broad practical application in cervical cancer diagnosis.

Effects of fullerene C60 with antihypoxants

BACKGROUND: Drug improvement is often carried out with the help of chemical modifications that improve the receptor action or transport of drugs to their target tissues.
 AIM: The aim of this study was to investigate the effect of combinations of C60 fullerene with amtizol, 2-amino-4-acetylthiazolo[5,4-b]indole, metaprot, metaprot base, and rutin on antihypoxic activities in a model of acute hypoxia with hypercapnia.
 MATERIALS AND METHODS: Several compounds with mono-, bi-, and tricyclic structures were examined separately or combined with C60 fullerene. All compounds, except for rutin, were synthesized at the Department of Pharmacology of the S.M. Kirov Military Medical Academy and contain active amino groups, nitrogen, and sulfur atoms in the cycles: amtizol (3,5-diamino-1,2,4-thiadiazole), VM-606 (2-amino-4-acetylthiazolo[5,4-b]indole), Metaprot (2-ethylthiobenzimidazole hydrobromide monohydrate), and Metaprot base. All compounds demonstrated antihypoxic activity. Hypobaric hypoxia was simulated in a flow pressure chamber by lifting animals to a height of 10,000 m at a speed of 50 m/s and exposure for 60 min. The preparations were administered intraperitoneally 60 min before the experiment. The protective effect was evaluated by the average life expectancy at altitude. Hypoxia with hypercapnia was assessed on male white mice weighing 2022 g, which were placed in 200 mL glass jars with hermetic lids, which were lowered under water to prevent air leakage. The studied preparations and their complexes with fullerene in the form of a thin suspension with Tween-80 were administered intraperitoneally min before hypoxia. The lifespan of the animals was recorded.
 RESULTS: The formation of the complex and its properties depend on the development of a donoracceptor bond between the drug and fullerene. An increase in the bioavailability of amtizol in the form of a complex with C60 fullerene increased the antihypoxic activity of the mixture by 40%. For the first time, dynamic curves of the activities of amtizol and 2-amino-4-acetylthiazolo[5,4-b]indole depending on time were obtained in a model of hypercapnic hypoxia.
 CONCLUSION: Fullerene C60 enhances the antihypoxic activity of the studied compounds due to an increase in the bioavailability of the antihypoxant caused by the microporation of tissue membranes due to the action of fullerene C60.