Electrospun green-emitting La2O2CO3:Tb3+ nanofibers and La2O2CO3:Tb3+/Eu3+ nanofibers with white-light emission and color-tuned photoluminescence

Color-tuned luminescence and white-light emission materials have attracted much attention owing to their broad application prospects. Generally, Tb³⁺ and Eu³⁺ co-doped phosphors have color-tuned luminescence, but white-light emission is rarely achieved. In this work, color-tunable photoluminescence and white light emission are achieved in Tb³⁺ and Tb³⁺/Eu³⁺ doped monoclinic-phase La₂O₂CO₃ one-dimensional (1D) nanofibers synthesized by electrospinning united with succedent strictly controlling calcination procedure. The prepared samples own excellent fibrous morphology. La₂O₂CO₃:Tb³⁺ nanofibers are the superior green-emitting phosphors. To obtain 1D nanomaterials with color-tunable fluorescence, particularly those with white-light emission, Eu³⁺ ions are further selected and doped into La₂O₂CO₃:Tb³⁺ nanofibers to obtain La₂O₂CO₃:Tb³⁺/Eu³⁺ 1D nanofibers. The major emission peaks of La₂O₂CO₃:Tb³⁺/Eu³⁺ nanofibers at 487, 543, 596 and 616 nm are attributed to ⁵D₄→⁷F₆ (Tb³⁺), ⁵D₄→⁷F₅ (Tb³⁺), ⁵D₀→⁷F₁ (Eu³⁺) and ⁵D₀→⁷F₂ (Eu³⁺) energy levels transitions under 250-nm (for Tb³⁺ doping) and 274-nm (for Eu³⁺ doping) UV light excitation, respectively. At different wavelengths excitation, La₂O₂CO₃:Tb³⁺/Eu³⁺ nanofibers with excellent stability achieve color-tuned fluorescence and white-light emission with the help of energy transfer from Tb³⁺ to Eu³⁺ and tuning the doping concentration of Eu³⁺ ions. Formative mechanism and fabrication technique of La₂O₂CO₃:Tb³⁺/Eu³⁺ nanofibers are advanced. The design concept and manufacturing technique developed in this work may offer fresh insights for synthesizing other 1D nanofibers doped with rare earth ions to tune emitting fluorescent colors.

Dendrimer-Modified Silica Nanoparticles for Efficient Enrichment of Low-Concentration Peptides

Peptide profiling based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is of particular interest as it can provide physiologically and pathologically related information of the bio-samples. Due to the complexity of real biological samples, MALDI-TOF MS-based peptide mapping methods rely strongly on particular enrichment methods to improve the signal intensity. This paper introduces third-generation dendrimer-modified SBA-15 with the surface functionalization of amino and carboxyl group, respectively (denoted as SBA-15/G3-NH₂ and SBA-15/G3-COOH), for the efficient capture of low-abundance peptides. The enrichment ability of the nanocomposites was evaluated by standard peptides digests and real biological samples. The synthesized nanocomposites incorporated the benefit of dendrimers and mesoporous silica nanomaterial SBA-15, showing enhanced peptide enrichment ability. Therefore, this work may provide a new class of nanomaterials for peptide mapping from biological samples.

Nanostructured Ceria: Biomolecular Templates and (Bio)applications

Ceria (CeO2) nanostructures are well-known in catalysis for energy and environmental preservation and remediation. Recently, they have also been gaining momentum for biological applications in virtue of their unique redox properties that make them antioxidant or pro-oxidant, depending on the experimental conditions and ceria nanomorphology. In particular, interest has grown in the use of biotemplates to exert control over ceria morphology and reactivity. However, only a handful of reports exist on the use of specific biomolecules to template ceria nucleation and growth into defined nanostructures. This review focusses on the latest advancements in the area of biomolecular templates for ceria nanostructures and existing opportunities for their (bio)applications.

C18-functionalized magnetic nanocomposites fabricated by one-step aqueous coating of tailored oligopeptides for enrichment of low-abundance peptides

Screening and monitoring endogenous peptides from complicated biosamples is still a major challenge in mass spectrometry-based proteomics research, mainly due to their low concentration and the interference of high-abundance proteins and other contaminants in biological samples. Herein, a facile and novel approach was described for rapid fabrication of C₁₈-functionalized magnetic nanocomposites (C₁₈-MNCs) based on one-step aqueous coating of C₁₈-Val-Lys-Val-Lys-Val-Lys (C₁₈-VK-VI) for the highly selective enrichment of low-abundance endogenous peptides from biological samples. C₁₈-VK-VI can readily self-assemble into complete monolayers mainly composed of β-sheets with C₁₈ hydrophobic chains erecting on the surface of GO@Fe₃O₄ MNCs under the physiological conditions. The resulting C₁₈VK-VI-GO@Fe₃O₄ MNCs exhibited good performance for peptides enrichment from digests of standard protein (myoglobin, MYO) and human serum, such as high sensitivity (0.05 fmol μL^-1) and selectivity (mass ratio of MYO digests and MYO = 1:500), rapid separation, and good reproducibility. Such a simple mild and rapid one-step aqueous coating method on the basis of oligopeptides self-assembly showed great potential in surface functionalization of various nanoadsorbents for proteome/peptidome researches.

PAMAM–PMAA brush-functionalized magnetic composite nanospheres: a smart nanoprobe with tunable selectivity for effective enrichment of mono-, multi-, or global phosphopeptides

A novel PAMAM–PMAA brush functionalized magnetic composite nanosphere was successfully prepared for selective enrichment of mono-, multi-, or global phosphopeptides by modulating buffer polarity and acidity.

Organic molecule-assisted synthesis of Fe3O4/graphene oxide nanocomposites for selective capture of low-abundance peptides and phosphopeptides

The iron oxide nanoparticles (Fe₃O₄) were prepared by organic molecule-assisted method in aqueous solution. The facile synthetic process of Fe₃O₄ nanoparticles was conducted only by mixing FeCl₂ and 2-methylimidazole (2-MIM) without any additives. A possible growth mechanism of the Fe₃O₄ nanocrystals was proposed for this mild reaction. Then, the Fe₃O₄ nanoparticles were anchored onto graphene oxide (GO) sheets in water by ultrasound-assisted method, forming an affinity probe with strong biocompatibility. Due to the hydroxy and carboxylic groups of GO sheets, Fe₃O₄/GO probe exhibits excellent performance for enriching low-abundance hydrophilic peptides, while the Fe₃O₄ nanoparticles endure the probe with specific affinity to phosphopeptides. The analytical protocol was developed for sequential enrichment of low-abundance peptides and phosphopeptides by the affinity probe. It exhibited the sequence coverage of 26% for capture of 17 low-abundance peptides from bovine serum albumin (BSA), as well as the selectivity of 1:1:100 for phosphopeptides from α-/β-casein/BSA, and low detectable concentration of 2.5 fmol and probe reusability of 5 times for capture of phosphopeptides from α-/β-casein. Consequently, the prepared Fe₃O₄/GO material possesses excellent feature as multifunctional affinity probe for low-abundance peptides including phosphopeptides from complex biological matrices detected by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

C8-modified magnetic graphene oxide based solid-phase extraction coupled with dispersive liquid-liquid microextraction for detection of trace phthalate acid esters in water samples

Phthalate acid esters (PAEs) are extensively applied in plastic and plastic products, and have caused potential hazards on human and animal health. In this study, a highly sensitive method was proposed for trace detection of selected PAEs in water by gas chromatography-mass spectrometry, after solid-phase extraction (SPE) using octyl (C8)-modified magnetic graphene oxide (MGO-C8) as the adsorbent followed by dispersive liquid-liquid microextraction (DLLME). The prepared MGO-C8 was characterized by Fourier transform infrared spectroscopy (FT-IR), thermo gravimetric analysis (TGA) and vibrating sample magnetometry (VSM). The recoveries of the PAEs using MGO-C8 as the adsorbent were found to be significantly higher those obtained by MGO. The influences of solution pH, adsorption and desorption time, eluent and extractant, and salt addition on the extraction efficiency of PAEs were investigated. Under the optimized conditions, limits of detection (LODs) of 0.5-1.0 ng L^-1 for PAEs, and related standard deviations (RSDs) of 4.8-7.5% were obtained. The proposed method was utilized in the detection of trace PAEs in real environmental water samples, with spiked recoveries of 89.5-112.3%, 91.5-105.0% and 98.0-110.0% for DBP, DEHP and DNOP, respectively.

Flexible sandwich-shaped composite film with simultaneous double electrically conductive anisotropy, magnetism and dual-color fluorescence

Flexible sandwich-shaped composite film with simultaneous double electrically conductive anisotropy, magnetism and dual-color fluorescence was successfully constructed via electrospinning.

Janus nanofiber array pellicle: facile conjugate electrospinning construction, structure and bifunctionality of enhanced green fluorescence and adjustable magnetism

A [Fe₃O₄/polyvinyl pyrrolidone (PVP)]//[Tb(BA)₃phen/PVP] Janus nanofiber array pellicle (denoted JNAP) was successfully constructed by facile conjugate electrospinning without twisting for the first time. The JNAP offers the dual-functionality of fluorescence and magnetism. This technology entirely solves the dilemma of the magnetic spinning dope and fluorescent spinning dope being easily mixed together during the parallel electrospinning process, as it achieves complete segregation of magnetic nanoparticles and fluorescent molecules. Moreover, conjugate electrospinning without twisting has fewer requirements on the viscosity of the spinning dope compared with parallel electrospinning, in which the two spinning dopes should have the same viscosity. It was satisfactorily found that the JNAP has higher fluorescence intensity than the corresponding non-aligned Janus nanofiber pellicle. The magnetism of the JNAP could be tailored by changing the doping amount of the Fe₃O₄ NPs. The JNAP has potential applications in nanotechnology and biomedicine, etc., due to its enhanced green fluorescence and adjustable magnetism. In addition, this design concept and manufacturing process provide a facile way for preparing other one-dimensional Janus nanomaterials with multifunctionality.

A [Fe₃O₄/PVP]//[Tb(BA)₃phen/PVP] Janus nanofiber array pellicle with enhanced green fluorescence and adjustable magnetism dual-functionality was constructed via facile conjugate electrospinning.

Efficient Synthesis of PVDF/PI Side-by-Side Bicomponent Nanofiber Membrane with Enhanced Mechanical Strength and Good Thermal Stability

Bicomponent composite fibers, due to their unique versatility, have attracted great attention in many fields, such as filtration, energy, and bioengineering. Herein, we efficiently fabricated polyvinylidene fluoride/polyimide (PVDF/PI) side-by-side bicomponent nanofibers based on electrospinning, which resulted in the synergism between PVDF and PI, and eventually obtained the effect of 1 + 1 > 2. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the morphology and chemical structure of nanofibers, indicating that a large number of side-by-side nanofibers were successfully prepared. Further, the thermal stability, mechanical strength, and filtration properties of PVDF/PI were carefully investigated. The results revealed that the bicomponent nanofibers possessed both good mechanical strength and remarkable thermal stability. Moreover, the mechanical properties of PVDF/ PI were strengthened by more than twice after the heat treatment (7.28 MPa at 25 °C, 15.49 MPa at 230 °C). Simultaneously, after the heat treatment at 230 °C for 30 min, the filtration efficiency of PVDF/PI membrane was maintained at about 95.45 ± 1.09%, and the pressure drop was relatively low. Therefore, the prepared PVDF/PI side-by-side bicomponent nanofibers have a favorable prospect of application in the field of medium- and high-temperature filtration, which further expands the application range of electrospun fiber membranes.

A Concentration-Dependent Insulin Immobilization Behavior of Alkyl-Modified Silica Vesicles: The Impact of Alkyl Chain Length

The insulin immobilization behaviors of silica vesicles (SV) before and after modification with hydrophobic alkyl -C₈ and -C₁₈ groups have been studied and correlated to the grafted alkyl chain length. In order to minimize the influence from the other structural parameters, monolayered -C₈ or -C₁₈ groups are grafted onto SV with controlled density. The insulin immobilization capacity of SV is dependent on the initial insulin concentrations (IIC). At high IIC (2.6-3.0 mg/mL), the trend of insulin immobilization capacity of SV is SV-OH > SV-C₈ > SV-C₁₈, which is determined mainly by the surface area of SV. At medium IIC (0.6-1.9 mg/mL), the trend changes to SV-C₈ ≥ SV-C₁₈ > SV-OH as both the surface area and alkyl chain length contribute to the insulin immobilization. At an extremely low IIC, the hydrophobic-hydrophobic interaction between the alkyl group and insulin molecules plays the most significant role. Consequently, SV-C₁₈ with longer alkyl groups and the highest hydrophobicity show the best insulin enrichment performance compared to SV-C₈ and SV-OH, as evidenced by an insulin detection limit of 0.001 ng/mL in phosphate buffered saline (PBS) and 0.05 ng/mL in artficial urine determined by mass spectrometry (MS).

Novel magnetic-fluorescent bifunctional Janus nanofiber membrane

Magnetic-fluorescent bifunctional materials have received global attention owing to their potential in many fields. Herein, we reported a novel magnetic-fluorescent bifunctional Janus nanofiber membrane (NFM) by adding the as-prepared magnetic CoFe₂O₄ nanoparticles into the polyacrylonitrile (PAN) side (m-PAN) and the fluorescent molecules of 1,8-naphthalene anhydride (1,8-NAD) into the polyvinylpyrrolidone (PVP) side (f-PVP) via electrospinning method. The obtained m-PAN/f-PVP Janus NFM exhibited excellent magnetic performance and high fluorescent properties due to the unique structure. Compared with the m-PAN/f-PVP composite NFM, the Janus NFM showed higher fluorescent performance because the fluorescent molecules were isolated from the magnetic nanoparticles. In addition, the Janus NFM not only maintain the good self-supporting state in water but also realize a directional movement attracted by a magnet. The unique structure of Janus nanofiber is of great importance and demonstrates great potential applications.

Assembling exceptionally-structured Janus nanoribbons into a highly anisotropic electrically conductive array film that exhibits red fluorescence and superparamagnetism

Exceptive-structured Janus nanoribbons and their array films demonstrating high conductive anisotropism, improved red fluorescence and superparamagnetism were constructed via electrospinning.

Double anisotropic electrically conductive flexible Janus-typed membranes

Novel type III anisotropic conductive films (ACFs), namely flexible Janus-typed membranes, were proposed, designed and fabricated for the first time. Flexible Janus-typed membranes composed of ordered Janus nanobelts were constructed by electrospinning, which simultaneously possess fluorescence and double electrically conductive anisotropy. For the fabrication of the Janus-typed membrane, Janus nanobelts comprising a conductive side and an insulative-fluorescent side were primarily fabricated, and then the Janus nanobelts are arranged into parallel arrays using an aluminum rotary drum as the collector to obtain a single anisotropically conductive film. Subsequently, a secondary electrospinning process was applied to the as-prepared single anisotropically conductive films to acquire the final Janus-typed membrane. For this Janus-typed membrane, namely its left-to-right structure, anisotropic electrical conduction synchronously exists on both sides, and furthermore, the two electrically conductive directions are perpendicular. By modulating the amount of Eu(BA)₃phen complex and conducting polyaniline (PANI), the characteristics and intensity of the fluorescence-electricity dual-function in the membrane can be tuned. The high integration of this peculiar Janus-typed membrane with simultaneous double electrically conductive anisotropy-fluorescent dual-functionality is successfully realized in this study. This design philosophy and preparative technique will provide support for the design and construction of new types of special nanostructures with multi-functionality.

Facile synthesis of core–shell structured magnetic covalent organic framework composite nanospheres for selective enrichment of peptides with simultaneous exclusion of proteins

Core–shell structured Fe₃O₄@TbBd composite nanospheres were synthesised using a facile approach and successfully applied for selective enrichment of peptides with simultaneous exclusion of proteins.

Assembly of 1D nanofibers into a 2D bi-layered composite nanofibrous film with different functionalities at the two layers via layer-by-layer electrospinning

A unique bi-layered composite nanofibrous film with trifunctionality of electrical conduction, magnetism and photoluminescence has been fabricated via layer-by-layer electrospinning.

Facile Synthesis of Mesocrystalline SnO2 Nanorods on Reduced Graphene Oxide Sheets: An Appealing Multifunctional Affinity Probe for Sequential Enrichment of Endogenous Peptides and Phosphopeptides

A novel multifunctional composite comprising mesocrystalline SnO₂ nanorods (NRs) vertically aligned on reduced graphene oxide (rGO) sheets was synthesized and developed for sequential capture of endogenous peptides and phosphopeptides. With the hydrophobicity of rGO and high affinity of SnO₂ nanorods, sequential enrichment of endogenous peptides and phosphopeptides could be easily achieved through a modulation of elution buffer. With this multifunctional nanomaterial, 36 peptides were observed from diluted bovine serum albumin (BSA) tryptic digest and 4 phosphopeptides could be selectively captured from β-casein digest. The detection limit of tryptic digest of β-casein was low to 4 × 10^-10 M, and the selectivity was up to 1:500 (molar ratio of β-casein and BSA digest). The effectiveness and robustness of rGO-SnO₂ NRs in a complex biological system was also confirmed by using human serum as a real sample. Our work is promising for small peptide enrichment and identification especially in complicated biological sample preparation, which also opens a new perspective in the design of multifunctional affinity probes for proteome or peptidome.