Conjugation Pattern Research Articles

Research on the Innovation of Arabic Interrogative Sentence Teaching Strategies

This study investigates innovative teaching strategies for Arabic interrogative sentences, aiming to enhance language learners’ proficiency and comprehension in this linguistic domain. The target audience for these strategies includes Arabic language instructors and learners seeking to improve their language skills. To achieve the objectives of the current research, the researcher designed 3 tables to identify the distinctions and commonalities between English and Arabic while recognizing the unique characteristics of each language. By examining syntactic structures, verb conjugation patterns, and cultural nuances, this research seeks to provide valuable insights into the complexities of Arabic interrogatives and offer practical pedagogical approaches for language instruction. This study also aims to address the significance of employing the right strategies in second language acquisition by providing a comprehensive review of existing literature on teaching Arabic interrogatives and proposing innovative pedagogical approaches based on cognitive grammar theory. This research then seeks to contribute to the field of Arabic language teaching by offering practical solutions to the challenges associated with interrogative sentence learning, thus empower learners to navigate real-world scenarios effectively and engage meaningfully with Arabic interrogative structures. In short, this research underscores the importance of adopting innovative teaching strategies for Arabic interrogative sentences to facilitate language learners’ proficiency and comprehension. By providing practical insights and pedagogical approaches, this study aims to enrich language instruction and contribute to the broader discourse on language teaching and learning.

Seismicity and fractal analysis in Aswan region, southern Egypt

Seismic activity in Aswan is influenced by the complex interactions of tectonic plates, the accumulation of stress, and the presence of geological fault systems. It revealed that epicenters are well distributed along four fault segments in a conjugate pattern, indicating a prominent E-W compressional stress. This research aims to explore the characteristics of seismicity and seismotectonics, with a focus on assessing their implications for risk reduction and disaster management in this densely populated region. A data review from the Egyptian National Seismological Network (ENSN) identified 464 earthquakes occurred between 2000 and 2021, with local magnitudes ranging from 0.3 to 4.4, and depths up to 25 km. The calculated Gutenberg-Richter b-value is approximately 0.87 ± 0.05, indicating a gradual stress accumulation. The current analysis shows a more consistent level of moderate seismic activity, unlike previous studies in Aswan region that reported a wide range of b-values from 0.554 to 1.07. This suggests that while earlier research captured a wider range of seismic behaviors, recent data indicates a stabilization in earthquake frequency and intensity. Additionally, the fractal dimension (Dc) calculated at 1.57 ± 0.04 shows an intermediate level of complexity and reflecting a clustering pattern of earthquakes. The variations in the b-value with different magnitudes and depths signify the involvement of active smaller faults, responsible for earthquakes up to magnitude 2.2, which then transition to fractured zones inducing earthquakes up to magnitude 2.5. This transition is followed by a decline in seismic activity, indicating regions that are potentially more likely to experience larger earthquakes. Moreover, stress disparities at various depths contribute to smaller earthquakes within the 5–10 km depth range. Return period analysis suggests that the earthquakes of magnitude 3.7 or higher are expected to occur approximately once every decade in Aswan. These findings are of utmost importance for earthquake risk reduction, hazard assessment, and the sustainable development of Aswan area.

Suspension Bead Loading (SBL): An Economical Protein Delivery Platform to Study URM1's Behavior in Live Cells.

Uniquely modified synthetic proteins are difficult to produce in large quantities, which could limit their use in various in vitro settings and in cellular studies. In this study, we developed a method named "suspension bead loading" (SBL), to deliver protein molecules into suspended living cells using glass beads, which significantly reduces the amount of protein required for effective delivery. We investigated the delivery efficiency of functionally different proteins and evaluated the cytotoxic effect of our method and the chemical and functional integrity of the delivered protein. We utilized SBL to address questions related to ubiquitin-related modifier 1 (URM1). Employing minimal protein quantities, SBL has enabled us to study its behavior within live cells under different redox conditions, including subcellular localization and conjugation patterns. We demonstrate that oxidative stress alters both the localization and conjugation pattern of URM1 in cells, highlighting its possible role in cellular response to such extreme conditions.

High-Performance Semiconducting Carbon Nanotube Transistors Using Naphthalene Diimide-Based Polymers with Biaxially Extended Conjugated Side Chains.

Polymer-wrapped single-walled carbon nanotubes (SWNTs) are a potential method for obtaining high-purity semiconducting (sc) SWNT solutions. Conjugated polymers (CPs) can selectively sort sc-SWNTs with different chiralities, and the structure of the polymer side chains influences this sorting capability. While extensive research has been conducted on modifying the physical, optical, and electrical properties of CPs through side-chain modifications, the impact of these modifications on the sorting efficiency of sc-SWNTs remains underexplored. This study investigates the introduction of various conjugated side chains into naphthalene diimide-based CPs to create a biaxially extended conjugation pattern. The CP with a branched conjugated side chain (P3) exhibits reduced aggregation, resulting in improved wrapping ability and the formation of larger bundles of high-purity sc-SWNTs. Grazing incidence X-ray diffraction analysis confirms that the potential interaction between sc-SWNTs and CPs occurs through π-π stacking. The field-effect transistor device fabricated with P3/sc-SWNTs demonstrates exceptional performance, with a significantly enhanced hole mobility of 4.72 cm2 V-1 s-1 and high endurance/bias stability. These findings suggest that biaxially extended side-chain modification is a promising strategy for improving the sorting efficiency and performance of sc-SWNTs by using CPs. This achievement can facilitate the development of more efficient and stable electronic devices.

Synthesis, Structures, Thermal stability and optical spectroscopy of Pt(II) di‑yne and poly‑yne incorporating 2,2′-Bipyridine-4,4′-diyl spacer

In platinum(II) di-ynes and poly-ynes the optical properties are influenced by the pattern of conjugation in the functionalised acetylide linker groups. We report the synthesis and characterisation of new Pt(II) di‑yne trans-[(Ph)(Et₃P)₂Pt–CC–Ar–CC–Pt(PEt₃)₂(Ph)] (Pt-M) and Pt(II) poly‑yne trans-[Pt(nBu3P)2Pt–CC–Ar–CC–]n (Pt-P) (Ar = 2,2′-bipyridine-4,4′-diyl) materials using analytical and spectroscopic techniques. The solid-state structure of the protected ligand precursor 4,4′-bis(trimethylsilylethynyl)-2,2′-bipyridine (LP1) and the dinuclear Pt(II) di‑yne (Pt-M) have been determined by the single-crystal X-ray diffraction (SC-XRD) while the number average molecular weight (Mn), weight average molecular weight (Mw) and polydispersity index (PDI) of the Pt(II) poly‑yne (Pt-P) have been determined by the gel permeation chromatography/light-scattering (GPC/LS) methods (Mn/Mw/PDI = 55,210/88,560/1.6). The thermal stability of the protected and di-terminal alkynyl ligands, Pt(II) di‑yne (Pt-M) and Pt(II) poly‑yne (Pt-P) have been evaluated and are discussed. To delineate the impact of incorporating the heavy Pt(II) ion along the polymer backbone, optical absorption studies have been performed and are discussed in detail. The results of optical absorption studies, especially (Pt-M) have been compared to their 5,5′- and 6,6′-bis(ethynyl) substituted analogues to better understand the effect of ligand topology on the effective conjugation.

Polycationic Open‐Shell Cyclophanes: Synthesis of Electron‐Rich Chiral Macrocycles, and Redox‐Dependent Electronic States

Abstractπ‐Conjugated chiral nanorings with intriguing electronic structures and chiroptical properties have attracted considerable interests in synthetic chemistry and materials science. We present the design principles to access new chiral macrocycles (1 and 2) that are essentially built on the key components of main‐group electron‐donating carbazolyl moieties or the π‐expanded aza[7]helicenes. Both macrocycles show the unique molecular conformations with a (quasi) figure‐of‐eight topology as a result of the conjugation patterns of 2,2’,7,7’‐spirobifluorenyl in 1 and triarylamine‐coupled aza[7]helicene‐based building blocks in 2. This electronic nature of redox‐active, carbazole‐rich backbones enabled these macrocycles to be readily oxidized chemically and electrochemically, leading to the sequential production of a series of positively charged polycationic open‐shell cyclophanes. Their redox‐dependent electronic states of the resulting multispin polyradicals have been characterized by VT‐ESR, UV/Vis‐NIR absorption and spectroelectrochemical measurements. The singlet (ΔES‐T=−1.29 kcal mol−1) and a nearly degenerate singlet‐triplet ground state (ΔES−T(calcd)=−0.15 kcal mol−1 and ΔES−T(exp)=0.01 kcal mol−1) were proved for diradical dications 12+2⋅ and 22+2⋅, respectively. Our work provides an experimental proof for the construction of electron‐donating new chiral nanorings, and more importantly for highly charged polyradicals with potential applications in chirospintronics and organic conductors.

Polycationic Open-Shell Cyclophanes: Synthesis of Electron-Rich Chiral Macrocycles, and Redox-Dependent Electronic States.

π-Conjugated chiral nanorings with intriguing electronic structures and chiroptical properties have attracted considerable interests in synthetic chemistry and materials science. We present the design principles to access new chiral macrocycles (1 and 2) that are essentially built on the key components of main-group electron-donating carbazolyl moieties or the π-expanded aza[7]helicenes. Both macrocycles show the unique molecular conformations with a (quasi) figure-of-eight topology as a result of the conjugation patterns of 2,2',7,7'-spirobifluorenyl in 1 and triarylamine-coupled aza[7]helicene-based building blocks in 2. This electronic nature of redox-active, carbazole-rich backbones enabled these macrocycles to be readily oxidized chemically and electrochemically, leading to the sequential production of a series of positively charged polycationic open-shell cyclophanes. Their redox-dependent electronic states of the resulting multispin polyradicals have been characterized by VT-ESR, UV/Vis-NIR absorption and spectroelectrochemical measurements. The singlet (ΔES-T=-1.29 kcal mol-1) and a nearly degenerate singlet-triplet ground state (ΔES-T(calcd)=-0.15 kcal mol-1 and ΔES-T(exp)=0.01 kcal mol-1) were proved for diradical dications 12+2⋅ and 22+2⋅, respectively. Our work provides an experimental proof for the construction of electron-donating new chiral nanorings, and more importantly for highly charged polyradicals with potential applications in chirospintronics and organic conductors.

Control over electronic structures of organic diradicaloids via precise B/O-heterocycle fusion

Diradicaloid polycyclic hydrocarbons (PHs) own unique open-shell electronic structures and exhibit potential utility in the fields of organic electronics and spintronics. Herein, we disclose precise fusion of B/O-heterocycles onto PHs for control over their electronic structures and diradical properties. We designed and synthesized four B/O-containing diradicaloid isomers that feature the fluoreno[3,2-b]fluorene and fluoreno[2,1-a]fluorene π-skeletons, respectively. The precise B/O-heterocycle fusion modes along with the changed conjugation patterns lead to their modulated electronic structures and properties, such as diradical and aromatic structures, energy levels and band gaps, as well as magnetic, electrochemical and photophysical properties. Notably, the mode A may decrease the open-shell extent, whereas the mode B can enhance the diradical nature, leading to their well-tuned diradical characters in the range of 0.46‒0.70. Moreover, the mode A stabilizes the LUMOs and the mode B obviously increases the HOMO levels, which are remarkably contributed by the B and O atoms, respectively, further giving rise to the decreased band gaps and redshifted absorptions. This study clearly illustrates the electronic effects of B/O-heterocycle fusion on PHs and gains insight into B/O-type organic diradicaloids. These findings will provide an important guideline for the design of more fascinating heteroatom-containing diradicaloids.

Strike‐slip fault zone architecture and its effect on fluid migration in deep‐seated strata: Insights from the Central Tarim Basin

AbstractThe internal fault architecture is crucial in assessing the significance of faults in fluid migration. The development of overlapping zones between segments and subsidiary structures is characteristic of a strike–slip faults. However, their internal architectures and roles in fluid migration are still poorly understood. The Tarim Basin's recently identified strike–slip faults imply that the petroleum resource is hosted in caves that were formed by subsequent dissolution after the formation of the fault zones in carbonate rocks, indicating that the internal fault architecture may be closely linked to the accumulation of petroleum. We investigated the architecture of the strike–slip fault zone using field, geochemical, seismic and well‐logging data. The results revealed that the strike–slip faults contain flower‐like structures in their vertical profiles and an en échelon and ‘X’ conjugate pattern in their horizontal slices. The fault core may become more complex because of the flower structure as fault breccia, slip surfaces, hydrothermal veins, dissolved pores and caves develop, and the damage zone contains multiple stages of fractures with high dip angles. Compared with ‘X’ pattern conjugate faults, NE‐trending strike–slip faults have a more developed and connected fault zone. The fault core acts as a fast conduit for fluid transport and experiences significant elemental losses, and the elemental variations in the damage zone may relate in long‐term and relatively lower‐level fluid–rock interactions. Three fault zone architecture models were created, namely, a releasing bend, a restraining bend and a single segment, and their controlling impacts on fluid migration were addressed accordingly. Our findings imply that fluid migration and accumulation are more favourable at the releasing bend than at the restraining bend and single segment.

VERBS IN UZBEK LINGUISTICS: A COMPREHENSIVE ANALYSIS

Verbs play a crucial role in the grammatical structure of any language. This article provides a comprehensive analysis of verbs in Uzbek linguistics, examining their morphological, syntactic, and semantic features. We explore the various verb forms, their conjugation patterns, tense, aspect, mood, and voice, along with their syntactic roles and semantic implications. The findings contribute to a deeper understanding of Uzbek verbs and offer insights into the broader field of Turkic linguistics.

Two series of benzofuran and benzodifuran chelating chromophores with DR/NIR emission and anticancer activity

Benzofuran (BF) and benzodifuran (BDF) based compounds are known for their tunable optical and biological properties. Recently, their potential as chelating and anticancer agents has been examined and exploited. As dyes emissive in a physiological environment are in high demand for integrated therapeutic and imaging tools, BF and BDF scaffolds came up as possible theranostic probes. Here, we examined two series of BF and BDF based compounds with an extended conjugation pattern and a half-salen group producing a copper (II) ion-chelating O,N,O tridentate site. A combined experimental and theoretical approach was employed in the examination of spectroscopic and cytotoxic properties. The novel compounds are emissive according to an aggregation-induced emission mechanism and exhibit the DR/NIR (deep red/near-infrared) fluorescence required for penetration into living tissue. The results collected against HeLa, A431, and MCF7 human cells were discussed and compared, detecting in one case a very good performance against tumor cells as well as selectivity towards healthy HaCaT cells.

On Fenchel c-conjugate dual problems for DC optimization: characterizing weak, strong and stable strong duality

In this paper we present two Fenchel-type dual problems for a DC (difference of convex functions) optimization primal one. They have been built by means of the c-conjugation scheme, a pattern of conjugation which has been shown to be suitable for evenly convex functions. We study characterizations of weak, strong and stable strong duality for both pairs of primal–dual problems. We also give conditions which relate the existence of strong and stable strong duality for both pairs.

Modelling of till microstructure development during subglacial deformation using ring shear experiments

Micromorphology has become a principal tool in glacial sedimentology providing a wealth of data on the geometry and kinematics of deformation histories and aiding our understanding of progressive and polyphase deformation. This approach has been applied to the detailed microstructural analysis of fabric development in nine samples of experimentally deformed till subjected to simple shear in a ring shear apparatus in order to model the progressive microfabric development during simulated subglacial deformation. Thin section analysis revealed that the relative strength and complexity of the clast microfabrics increases with increasing cumulative shear distance (0–1152 cm) and cumulative shear strain (0–549), whereas microfabric strength increases rapidly during the initial stages of shearing (cumulative strain up to ∼20) and remains relatively stable at higher cumulative strain (>200). In addition microfabric development is heterogeneous reflecting the partitioning of deformation at a microscale. A conjugate pattern of clast long axis alignment identified in the un-sheared sample taken at the start of the experiment formed during the initial consolidation and draining of the till. This emphasises that water-rich unconsolidated tills have the potential to be highly responsive to any applied stress even at very low strains. This un-sheared fabric was overprinted at a very early stage of the experiment when cumulative shear strains were below 5. The complex microfabrics formed during simple shear record the progressive development of up-shear dipping P-shears, down-shear dipping R-shears, and subhorizontal Y-shears. Sigmoidal fabric geometries, comparable to S–C and ECC-type fabrics, associated with the Riedel shears record a consistent sinistral sense of shear, i.e. the direction of shear imposed by the rotating plate of the ring shear. Observed changes in the relationships between these microfabrics record the switching between the localised imposition of a compressional fabric and P-shear formation, to subhorizontal shear and the formation of Y-shears accompanied by extension and the growth of low-angle R-shears, and back again. This process may potentially lead to alternating phases of “stick” (compression) and “slip” (subhorizontal shear) recognised as a key feature of glacier motion occurring in response to soft-sediment bed deformation. Multiple cycles of microstructure overprinting and rejuvenation pose a major challenge on determining the cumulative strain of subglacially deformed tills of unknown history from micromorphological signatures alone.

Complex rupture process on the conjugate fault system of the 2014 Mw 6.2 Thailand earthquake

A moment magnitude 6.2 crustal earthquake occurred in northern Thailand on May 5, 2014, and its aftershocks exhibit several lineaments with conjugate pattern, involving geometric complexity in a multi-segmented fault system of the Phayao Fault Zone. However, a relationship between those geometric complexities and the rupture evolution of the 2014 Thailand earthquake is still elusive, which is critical to understand complex nature of the earthquake physics and to assess the hazard. Here, we elaborated the newly developed potency density tensor inversion method, used it to invert the globally observed teleseismic P waveforms, and estimated the spatiotemporal distribution of both the slip and the fault geometry. We found the complex rupture evolution consisting of two rupture episodes along a conjugated strike-slip fault system that comprises two distinct fault planes. The first episode originated at the hypocenter and the rupture propagated south along the north–northeast to south–southwest fault plane. The second episode was triggered at around 5 km north from the epicenter, and the rupture propagated along the east–northeast to west–southwest fault plane and terminated at the west end of the source area at 5 s hypocentral time. Our work demonstrates that our potency density tensor inversion can be applied to the smaller-scale magnitude-6 class earthquakes, and it resolves the complex rupture process controlled by the underlying geometric complexity in the fault system.

Children Born of Rebel Captivity: Politics and Practices of Integration in Uganda

Many studies have documented and analyzed the Lord's Resistance Army (LRA) forced conjugal association patterns and practices (“forced marriage”). However, the focus has been on the experiences of abducted girls forced to serve as conjugal partners to commanders (“forced wives”). The experiences of children born as a result of these relationships are under-investigated. Receptor communities in northern Uganda are assumed to be places of hope, comfort, and protection for these children. However, they can also be hostile, leaving the children in precarious and vulnerable situations. This article draws from ethnographic fieldwork in the Acholi region and interviews with formerly abducted mothers focusing on their children's integration processes and experiences. It argues that return is not integration, as it often coincides with further exclusion and alienation. In Uganda's patriarchal and patrilineal social systems, children with no paternal lineage are viewed as of lower status. Stigmatization facing children born of the LRA captivity condemns them to this status, consequently excluding them from mainstream society. Findings show that stigma remains central to the life experiences of these children several years after the end of the conflict in 2006. Their persistent stigmatization is linked to broader discriminatory socio-cultural and patriarchal ideas and practices.

A broad, exposome-type evaluation of xenobiotic phase II biotransformation in human biofluids by LC-MS/MS

Abstract Xenobiotics are chemicals foreign to a specific organism that humans are exposed to on a daily basis through their food, drugs, and the environment. These molecules are frequently metabolized to increase polarity and subsequent excretion. During sample preparation, deconjugation of phase II metabolites is a critical step to capture the total exposure to chemicals in liquid chromatography mass spectrometry (LC-MS) assays. Knowledge on deconjugation efficiencies of different enzymes and the extent of conjugation in human biofluids has primarily been investigated for single compounds or individual chemical classes. In this study, the performance of three β-glucuronidase and arylsulfatase mixtures from Helix pomatia, from recombinant sources (BGS™), and from Escherichia coli combined with recombinant arylsulfatase (ASPC™) was compared and the efficiency of phase II deconjugation was monitored in breast milk, urine, and plasma. An innovative LC-MS/MS biomonitoring method encompassing more than 80 highly diverse xenobiotics (e.g., plasticizers, industrial chemicals, mycotoxins, phytoestrogens, and pesticides) was utilized for the comprehensive investigation of phase II conjugation in breast milk and urine samples obtained from breastfeeding women. Overall, it was confirmed that H. pomatia is the most efficient enzyme in hydrolyzing different classes of xenobiotics for future exposome-scale biomonitoring studies. The recombinant BGS™ formulation, however, provided better results for breast milk samples, primarily due to lower background contamination, a major issue when employing the typically applied crude H. pomatia extracts. A deeper understanding of the global xenobiotic conjugation patterns will be essential for capturing environmental and food-related exposures within the exposome framework more comprehensively.

Set-Valued Evenly Convex Functions: Characterizations and C-Conjugacy

In this work we deal with set-valued functions with values in the power set of a separated locally convex space where a nontrivial pointed convex cone induces a partial order relation. A set-valued function is evenly convex if its epigraph is an evenly convex set, i.e., it is the intersection of an arbitrary family of open half-spaces. In this paper we characterize evenly convex set-valued functions as the pointwise supremum of its set-valued e-affine minorants. Moreover, a suitable conjugation pattern will be developed for these functions, as well as the counterpart of the biconjugation Fenchel-Moreau theorem.

Horseradish peroxidase catalyzed grafting of chitosan oligosaccharide with different flavonols: structures, antioxidant activity and edible coating application.

Enzymatic catalyzed grafting of oligosaccharides with polyphenols is a safe and environmentally friendly approach to simultaneously enhance the bioactivity of oligosaccharides and the solubility of polyphenols. In this study, chitosan oligosaccharide (COS) was grafted with three different flavonols including myricetin (MYR), quercetin (QUE) and kaempferol (KAE) by horseradish peroxidase (HRP) catalysis. The structures, antioxidant activity and edible coating application of COS-flavonol conjugates were investigated. The total phenol content of COS-MYR, COS-QUE and COS-KAE conjugates was 59.89, 68.37 and 53.77 mg gallic acid equivalents g-1 , respectively. Thin layer chromatography showed the conjugates did not contain ungrafted flavonols. COS-flavonol conjugates showed ultraviolet absorption peak at about 294 nm, corresponding to the A-ring of flavonols. Fourier-transform infrared spectra of conjugates confirmed the formation of Schiff-base and Michael-addition products. The proton-nuclear magnetic resonance spectrum of COS-KAE conjugate exhibited phenyl proton signals of KAE. X-ray diffraction patterns of conjugates showed some diffraction peaks of flavonols. COS-flavonol conjugates presented rough and porous morphologies with sheet-like and/or blocky structures. The conjugates showed higher water solubility, free radical scavenging activity and reducing power than flavonols. Moreover, fish gelatin/COS-flavonol conjugate coatings effectively prolonged the shelf life of refrigerated largemouth bass (Micropterus salmoides) fillets from 5 days to 7-8 days. COS-flavonol conjugates prepared by HRP catalysis have great potentials as novel antioxidant agents. © 2022 Society of Chemical Industry.

Silver Nanoparticles Functionalized With Antimicrobial Polypeptides: Benefits and Possible Pitfalls of a Novel Anti-infective Tool.

Silver nanoparticles (AgNPs) and antimicrobial peptides or proteins (AMPs/APs) are both considered as promising platforms for the development of novel therapeutic agents effective against the growing number of drug-resistant pathogens. The observed synergy of their antibacterial activity suggested the prospect of introducing antimicrobial peptides or small antimicrobial proteins into the gelatinized coating of AgNPs. Conjugates with protegrin-1, indolicidin, protamine, histones, and lysozyme were comparatively tested for their antibacterial properties and compared with unconjugated nanoparticles and antimicrobial polypeptides alone. Their toxic effects were similarly tested against both normal eukaryotic cells (human erythrocytes, peripheral blood mononuclear cells, neutrophils, and dermal fibroblasts) and tumor cells (human erythromyeloid leukemia K562 and human histiocytic lymphoma U937 cell lines). The AMPs/APs retained their ability to enhance the antibacterial activity of AgNPs against both Gram-positive and Gram-negative bacteria, including drug-resistant strains, when conjugated to the AgNP surface. The small, membranolytic protegrin-1 was the most efficient, suggesting that a short, rigid structure is not a limiting factor despite the constraints imposed by binding to the nanoparticle. Some of the conjugated AMPs/APs clearly affected the ability of nanoparticle to permeabilize the outer membrane of Escherichia coli, but none of the conjugated AgNPs acquired the capacity to permeabilize its cytoplasmic membrane, regardless of the membranolytic potency of the bound polypeptide. Low hemolytic activity was also found for all AgNP-AMP/AP conjugates, regardless of the hemolytic activity of the free polypeptides, making conjugation a promising strategy not only to enhance their antimicrobial potential but also to effectively reduce the toxicity of membranolytic AMPs. The observation that metabolic processes and O2 consumption in bacteria were efficiently inhibited by all forms of AgNPs is the most likely explanation for their rapid and bactericidal action. AMP-dependent properties in the activity pattern of various conjugates toward eukaryotic cells suggest that immunomodulatory, wound-healing, and other effects of the polypeptides are at least partially transferred to the nanoparticles, so that functionalization of AgNPs may have effects beyond just modulation of direct antibacterial activity. In addition, some conjugated nanoparticles are selectively toxic to tumor cells. However, caution is required as not all modulatory effects are necessarily beneficial to normal host cells.

Directional immobilization of antibody onto magnetic nanoparticles by Fc-binding protein-assisted photo-conjugation for high sensitivity detection of antigen

Immobilized antibodies with site-specific, oriented, and covalent pattern are of great significance to improve the sensitivity of solid-phase immunoassay. Here, we developed a novel antibody conjugation strategy that can immobilize antibodies in a directional and covalent manner. In this study, an IgG-Fc binding protein (Z domain) carrying a site-specific photo-crosslinker, p-benzoyl-L-phenylalanine, and a single C-terminal cysteine (Cys) handle was genetically engineered. Upon UV irradiation, the chimeric protein enables the Cys handle to couple with the native antibody in Fc-specific and covalent conjugation pattern, resulting in a novel thiolated antibody. Thus, an approach for the covalent, directional immobilization of antibodies to maleimide-modified magnetic nanoparticles (MNPs) was developed on the basis of the crosslinking between sulfhydryl and maleimide groups. The antibody-conjugated MNPs were applied in MNP-based enzyme-linked immunosorbent assay (ELISA) for the detection of carcinoembryonic antigen. The MNP-based ELISA presented a quantification linear range of 0.1–100 ng mL−1 and detection limit of 0.02 ng mL−1, which was approximately 100 times more sensitive than the traditional microplate ELISA (2.0 ng mL−1). Thus, the proposed antibody immobilization approach can be used in surface functionalization for the sensitive detection of various biomarkers.