Poly(l-lactide) (PLLA)-based nanoparticles have attracted much attention with respect to applications in drug delivery and nanomedicine as a result of their biocompatibility and biodegradability. ...Nevertheless, the ability to prepare PLLA assemblies with well-defined shape and dimensions is limited and represents a key challenge. Herein we report access to a series of monodisperse complex and hierarchical colloidally stable 2D structures based on PLLA cores using the seeded growth, “living-crystallization-driven self-assembly” method. Specifically, we describe the formation of diamond-shaped platelet micelles and concentric “patchy” block co-micelles by using seeds of the charge-terminated homopolymer PLLA24PPh2MeI to initiate the sequential growth of either additional PLLA24PPh2MeI or a crystallizable blend of the latter with the block copolymer PLLA42-b-P2VP240, respectively. The epitaxial nature of the growth processes used for the creation of the 2D block co-micelles was confirmed by selected area electron diffraction analysis. Cross-linking of the P2VP corona of the peripheral block in the 2D block co-micelles using Pt nanoparticles followed by dissolution of the interior region in good solvent for PLLA led to the formation of novel, hollow diamond-shaped assemblies. We also demonstrate that, in contrast to the aforementioned results, seeded growth of the unsymmetrical PLLA BCPs PLLA42-b-P2VP240 or PLLA20-b-PAGE80 alone from 2D platelets leads to the formation of diamond-fiber hybrid structures.
Colloidally stable suspensions of lead halide perovskite nanocrystals are prepared from high‐quality lead halide nanocrystal seeds. Perovskite nanocrystals with different layered crystal structures ...are reported. These systems are well suited for investigations of the intrinsic photophysics and spectroscopy of organic–inorganic metal halide perovskites.
Self-seeding is a process unique to polymer crystals, which consist of regions of different chain packing order and different crystallinity. Here we report the synergistic self-seeding behaviour of ...pairs of core-crystalline block copolymer (BCP) micelle fragments and show how this strategy can be employed to control the morphology of these BCP comicelles. Each micelle fragment has a critical dissolution temperature (
), and unimers of each BCP have a characteristic epitaxial growth rate. The
value affects the dissolution sequence of the fragments upon heating, while the unimer growth rate affects the growth sequence upon cooling. By carefully choosing micelle fragments having different
values as well as growth rates, we could prepare patchy comicelles and block comicelles with uniform and controllable length. This synergistic self-seeding strategy is a simple yet effective route to control both length and morphology of core-crystalline comicelles.
Nature uses orthogonal interactions over different length scales to construct structures with hierarchical levels of order and provides an important source of inspiration for the creation of ...synthetic functional materials. Here, we report the programmed assembly of monodisperse cylindrical block comicelle building blocks with crystalline cores to create supermicelles using spatially confined hydrogen-bonding interactions. We also demonstrate that it is possible to further program the self-assembly of these synthetic building blocks into structures of increased complexity by combining hydrogen-bonding interactions with segment solvophobicity. The overall approach offers an efficient, non-covalent synthesis method for the solution-phase fabrication of a range of complex and potentially functional supermicelle architectures in which the crystallization, hydrogen-bonding and solvophobic interactions are combined in an orthogonal manner.
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•High Quantum Yield: The synthesized coumarin dyes exhibited high quantum yields, ranging from 0.55 to 0.94, indicating their efficiency in fluorescence. This property is essential ...for their potential use in sensitive fluorescence-based applications.•Solvent Sensitivity: The dyes demonstrated varying degrees of sensitivity to different solvents. This was assessed using UV fluorescence, time-correlated single photon counting (TCSPC), and time-resolved spectroscopy (TRES). This sensitivity is crucial for applications in solvent-based systems and molecular sensing.•Fluorescence Decay Characteristics: The study revealed that most dye-solvent combinations exhibited single exponential decay with lifetimes ranging from 2.3 to 3 ns. However, deviations from single exponential behavior were observed in specific solvent environments, providing insights into the dynamic interactions between the dyes and their solvent matrices.•Effect of Structural Modifications: The impact of different substituents on the coumarin core was significant. For instance, dyes with a piperazine moiety showed significant deviations in fluorescence behavior compared to those with methoxy groups, suggesting that the electronic properties of the substituents greatly influence the photophysical outcomes.•Interaction with Silica Nanoparticles: The interactions of the dyes with silica nanoparticles (Ludox) were explored, showing changes in the spectroscopic properties of the dyes. This result suggests potential applications in nanoparticle-based systems and could lead to new developments in nano-bio conjugates for imaging and sensing.•Potential for FRET Applications: Based on the fluorescence characteristics and quantum yields, the dyes were evaluated for their potential in fluorescence resonance energy transfer (FRET) experiments. This could be pivotal for developing advanced biosensors and molecular probes.
Coumarin dyes are highly versatile and widely employed as fluorescent chemosensors in a variety of fields, including molecular imaging, bioorganic chemistry, analytical chemistry, materials chemistry, biology, and medical science. Thanks to their outstanding photostability and high quantum yield, they represent an ideal choice for developing sensitive and selective sensing platforms. In this study, we successfully designed and synthesized four new dyes based on the coumarin dye molecular skeleton, investigating their solvent sensitivity and spectroscopic properties. Our novel coumarin dyes were synthesized by a straightforward approach, reacting coumarin-3-carboxylic acid succinimidyl ester derivatives with corresponding amines in 1,4-dioxane as a solvent. We carefully monitored the completion of the reactions using thin-layer chromatography (TLC) and characterized these dyes using spectral and elemental analyses. We further investigated the UV, fluorescence, time-correlated single photon counting (TCSPC) technique and time-resolved spectroscopy (TRES) of these dyes in different solvents and on polymer film poly(methyl methacrylate) (PMMA). The quantum yield of the synthesized dyes was determined, with values observed to range between 0.55 and 0.94. Most of the dye-solvent and dye-polymer combinations exhibited single exponential decay, with lifetimes ranging from 2.3 to 3 ns. Minor deviations from single exponential behavior were observed for most of the dyes in toluene, while significant deviations were observed for coumarin dyes with piperazine moiety. We have provided a rationalization of these results in terms of the chemical functionalities of the various dyes. Furthermore, we investigated the effect of interactions between 7-methoxy-2-oxo-N-(2-(piperazin-1-yl)ethyl)–2H-chromene-3-carboxamide and silica nanoparticles (Ludox) on the spectroscopic properties of these dyes, with charge transfer being one possible mechanism contributing to the behavior of the dyes. Additionally, we explored the effect of trifluoroacetic acid (TFA) on the dyes’ emission intensity and fluorescence decay. Based on our UV and fluorescence measurements of the dyes in different solvents, we have concluded that these dyes can create excellent donor–acceptor pairs for our upcoming fluorescence resonance energy transfer (FRET) experiments.
Precise control over the morphology and dimensions of block copolymer (BCP) micelles has attracted interest due to the potential of this approach to generate functional nanostructures. Incorporation ...of liquid crystalline (LC) block can provide additional ways to vary micellar morphologies, but the formation of uniform micelles with controllable dimensions from LC BCPs has not yet been realized. Herein, we report the preparation of monodisperse cylindrical micelles with a LC poly(2‐(perfluorooctyl)ethyl methacrylate (PFMA) core via a fragmentation‐thermal annealing (F‐TA) process, resembling the “self‐seeding” process of crystalline BCP micelles. The average length of the cylinders increases with annealing temperature, with a narrow length distribution (Lw/Ln<1.1). We also demonstrate the potential application of the cylinders with LC cores as a cargo‐carrier by the successful incorporation of a hydrophobic fluorescent dye tagged with a fluorooctyl group.
“Liquid” centers: Cylindrical block copolymer micelles with a perfluorinated liquid‐crystalline core‐forming block undergo a fragmentation‐thermal annealing process that resembles the “self‐seeding” phenomenon. The resulting cylindrical micelles have a controlled length and a narrow length distribution. The cylinders can be used as a cargo‐carrier, as shown with a fluorescent dye.
There is a broad interest in elongated colloids as drug delivery vehicles, and current research aims to address how their length and aspect ratio affect interactions with cells. Block copolymer (BCP) ...micelles offer the opportunity to vary micelle length while maintaining cross-sectional width with corona chains that maintain a common surface chemistry across these structures. However, most elongated BCP micelles used in cell studies are characterized by a very broad length distribution. Here, we describe the synthesis and self-assembly properties of a diblock copolymer with a polyferrocenylsilane core-forming block and a corona block consisting of a statistical polymer of (aminopropyl)methacrylamide and oligo(ethylene glycol methacrylate) (M = 500) (PFS27-b-PAPMA3-stat-OEGMA48). Self-assembly in water gave a mixture of structures including rodlike micelles. In alcohols, different types of structures were obtained depending on the alcohol employed (butanol, 2-propanol, ethanol, and methanol). In ethanol, the polymer formed long micelles of uniform width by crystallization-driven self-assembly. Following sonication, a series of rodlike micelles with different lengths (80 to 2000 nm) and narrow length distributions (L w/L n < 1.10) were generated by seeded growth. These micelles could be transferred to aqueous media and maintained colloidally stable in PBS (phosphate-buffered saline) buffer for more than three months. In these micelles, the POEGMA brush provides a “stealth” coating to minimize the interaction with proteins and cells, and the APMA groups provide functionality for attachment of drugs or metal chelators for potential therapeutic applications. Studies in two human breast cancer cell lines (MDA-MB-231 and MDA-MB-436) show no signs of toxicity for micelle concentrations up to 0.1 mg·mL–1. We also show that metal chelators can be covalently attached to the amino groups in the corona and labeled with heavy metals, opening the door to future experiments with radionuclides.
We report the preparation of multi-armed micelles and block co-micelles using the crystallization-driven self-assembly of crystalline-coil polyferrocenylsilane block copolymers from nanocrystals of ...the homopolymer. The resulting multi-armed micelles possessed hierarchical multipod structures with monodisperse and tunable arm lengths. The termini of the arms remained active to the addition of further block copolymer unimers, and multi-armed block co-micelles with segmented arm chemistries and variable segment sequences were prepared. Coronal cross-linking followed by nanocrystal dissolution led to the release of non-centrosymmetric AB cylindrical diblock co-micelles.
Mass cytometry is an emerging powerful bioanalytical technique for high-dimensional single-cell analysis. In this technique, cells are stained with metal-isotope-tagged antibodies and are analyzed by ...an inductively coupled plasma time-of-flight mass spectrometer. While there are more than 100 stable isotopes available in the
m
/
z
75 to 209 detection range of the instrument, only about 50 parameters can be measured per cell because current reagents are metal-chelating polymers with pendant aminocarboxylate chelators that only bind hard metal ions such as the rare earths and Bi
3+
. Here we describe the synthesis and characterization of a new type of metal-chelating polymer with pendant dipicolylamine chelators suited to binding intermediate to soft metals such as rhenium and platinum. We introduce two different conjugation strategies, a thiol-maleimide reaction that works well for rhenium, and a DBCO-azide click reaction designed to avoid potential complications of Pt and other heavy metals interacting with thiol groups. We show that these polymers can serve as new elemental mass tags for mass cytometry. Antibody-polymer conjugates of CD20 and CD8a prepared by both coupling reactions were employed in conjunction with commercial metal-conjugated antibodies for multi-parameter single-cell immunoassays.
A new type of metal-chelating polymer with pendant dipicolylamine chelators that bind rhenium and platinum has been developed for mass cytometry applications.
Do it yourself: When short fragments (ca. 50 nm) of rodlike PI‐PFS block copolymer micelles in decane are heated above a characteristic temperature (60 °C) and then cooled to room temperature, a ...smaller number of longer micelles with a narrow length distribution are obtained. This process resembles self‐seeding of polymer crystals, involving selective dissolution of the fragments of the lowest degree of crystallinity with the surviving submicroscopic seeds acting as nuclei for the growth of micelles upon cooling.
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