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The present article reports a simple and straightforward approach to access thermoresponsive graft copolymers based on lactide (LA) and a methacrylic monomer, 2‐hydroxypropyl methacrylate (HPMA), using a synthesized carboxy‐functionalized trithiocarbonate‐based chain transfer agent. One protocol involves a metal‐free simultaneous synthesis through a combination of reversible addition‐fragmentation chain transfer polymerization and organic acid‐catalyzed ring‐opening polymerization, which follows first‐order kinetics. The resulting copolymers with a controlled structure exhibit remarkably narrow molecular weight distributions (Ð < 1.10). Within this framework, the self‐assembly of PHPMA‐g‐PLA graft copolymers (GCs) into nanoparticles (NPs) is demonstrated at concentrations of 0.2 and 0.5 wt.%, respectively. The displacement method, based on the rapid injection of the organic solvent (acetone) into an aqueous medium under vigorous stirring, produces spherical NPs such as micelles, vesicles, or non‐spherical "lumpy rods". The presence of a pseudo‐thermoresponsive segment (PHPMA) in GCs facilitates stimulus‐responsive self‐assembly behavior. Well‐defined spherical NPs—primarily vesicles of substantial size—develop upon heating above the glass transition temperature (Tg ≈35–36 °C) of the GCs in an acetone–water (80/20 wt.%) mixture. Last, specific interactions between the obtained PHPMA‐g‐PLA nano‐objects and blood proteins in human plasma are studied using isothermal calorimetry. [ABSTRACT FROM AUTHOR]

In the current work, we present the successful functionalization and stabilization of P-25 TiO2 nanoparticles by means of N1,N7-bis(3-(4- tert-butyl-pyridium-methyl)phenyl)-4-(3-(3-(4- tert-butyl-pyridinium-methyl)phenylamino)-3-oxopropyl)-4-(3,4-dihydroxybenzamido)heptanediamide tribromide ( 1). The design of the latter is aimed at nanoparticle functionalization and stabilization with organic building blocks. On one hand, 1 features a catechol anchor to enable its covalent grafting onto the TiO2 surface, and on the other hand, positively charged pyridine groups at its periphery to prevent TiO2 agglomeration through electrostatic repulsion. The success of functionalization and stabilization was corroborated by thermogravimetric analysis, dynamic light-scattering, and zeta potential measurements. As a complement to this, the formation of layer-by-layer assemblies, which are governed by electrostatic interactions, by alternate deposition of functionalized TiO2 nanoparticles and two negatively charged porphyrin derivatives, that is, 5,10,15,20-(phenoxyacetic acid)-porphyrin ( 2) and 5,10,15,20-(4-(2-ethoxycarbonyl)-4-(2-phenoxyacetamido)heptanedioic acid)-porphyrin ( 3), is documented. To this end, the layer-by-layer deposition is monitored by UV/Vis spectroscopy, scanning electron microscopy, ellipsometry, and profilometry techniques. The resulting assemblies are utilized for the construction and testing of novel solar cells. From stable and repeatable photocurrents generated during several 'on-off' cycles of illumination, we derive monochromatic incident photo-to-current conversion efficiencies of around 3 %. [ABSTRACT FROM AUTHOR]

Multimodal imaging, integrating several modalities including down- and up-conversion luminescence, T1- and T2(T2*)-weighted MRI, and CT contrasting in one system, is very promising for improved diagnosis of severe medical disorders. To reach the goal, it is necessary to develop suitable nanoparticles that are highly colloidally stable in biologically relevant media. Here, hydrophilic poly(N,N-dimethylacrylamide-N-acryloylglycine methyl ester)-alendronate-[P(DMA-AGME)-Ale]-coated Gd(Tb)F3:Tb3+(Gd3+),Yb3+,Nd3+ nanoparticles were synthesized by a coprecipitation method in ethylene glycol (EG) followed by coating with the polymer. The particles were tho-roughly characterized by a dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray energy dispersive spectroscopy (EDAX), selected area electron diffraction (SAED), elemental ana-lysis and fluorescence spectroscopy. Aqueous particle dispersions exhibited excellent colloidal stability in water and physiological buffers. In vitro toxicity assessments suggested no or only mild toxicity of the surface-engineered Gd(Tb)F3:Tb3+(Gd3+),Yb3+,Nd3+ particles in a wide range of concentrations. Internalization of the particles by several types of cells, including HeLa, HF, HepG2, and INS, was confirmed by a down- and up-conversion confocal microscopy. Newly developed particles thus proved to be an efficient contrast agent for fluorescence imaging, T1- and T2(T2*)-weighted magnetic resonance imaging (MRI), and computed tomography (CT). [ABSTRACT FROM AUTHOR]

"All-in-one" multifunctional nanomaterials, which can be visualized simultaneously by several imaging techniques, are required for the efficient diagnosis and treatment of many serious diseases. This report addresses the design and synthesis of upconversion magnetic NaGdF4:Yb3+/Er3+(Tm3+) nanoparticles by an oleic acid-stabilized high-temperature coprecipitation of lanthanide precursors in octadec-1-ene. The nanoparticles, which emit visible or UV light under near-infrared (NIR) irradiation, were modified by in-house synthesized PEG-neridronate to facilitate their dispersibility and colloidal stability in water and bioanalytically relevant phosphate buffered saline (PBS). The cytotoxicity of the nanoparticles was determined using HeLa cells and human fibroblasts (HF). Subsequently, the particles were modified by Bolton-Hunter-neridronate and radiolabeled by 125I to monitor their biodistribution in mice using single-photon emission computed tomography (SPECT). The upconversion and the paramagnetic properties of the NaGdF4:Yb3+/Er3+(Tm3+)@PEG nanoparticles were evaluated by photoluminescence, magnetic resonance (MR) relaxometry, and magnetic resonance imaging (MRI) with 1 T and 4.7 T preclinical scanners. MRI data were obtained on phantoms with different particle concentrations and during pilot long-time in vivo observations of a mouse model. The biological and physicochemical properties of the NaGdF4:Yb3+/Er3+(Tm3+)@PEG nanoparticles make them promising as a trimodal optical/MRI/SPECT bioimaging and theranostic nanoprobe for experimental medicine. [ABSTRACT FROM AUTHOR]

The development of stimuli-responsive drug delivery systems enables targeted delivery and environment-controlled drug release, thereby minimizing off-target effects and systemic toxicity. We prepared and studied tailor-made dual-responsive systems (thermo- and pH-) based on synthetic diblock copolymers consisting of a fully hydrophilic block of poly[ N -(1,3-dihydroxypropyl)methacrylamide] (poly(DHPMA)) and a thermoresponsive block of poly[ N -(2,2-dimethyl-1,3-dioxan-5-yl)methacrylamide] (poly(DHPMA-acetal)) as drug delivery and smart stimuli-responsive materials. The copolymers were designed for eventual medical application to be fully soluble in aqueous solutions at 25 °C. However, they form well-defined nanoparticles with hydrodynamic diameters of 50-800 nm when heated above the transition temperature of 27-31 °C. This temperature range is carefully tailored to align with the human body's physiological conditions. The formation of the nanoparticles and their subsequent decomposition was studied using dynamic light scattering (DLS), transmission electron microscopy (TEM), isothermal titration calorimetry (ITC), and nuclear magnetic resonance (NMR). 1 H NMR studies confirmed that after approximately 20 h of incubation at pH 5, which closely mimics tumor microenvironment, approximately 40% of the acetal groups were hydrolyzed, and the thermoresponsive behavior of the copolymers was lost. This smart polymer response led to disintegration of the supramolecular structures, possibly releasing the therapeutic cargo. By tuning the transition temperature to the values relevant for medical applications, we ensure precise and effective drug release. In addition, our systems did not exhibit any cytotoxicity against any of the three cell lines. Our findings underscore the immense potential of these nanoparticles as eventual advanced drug delivery systems, especially for cancer therapy.

This study outlines the microfluidic (MF) controlled self-assembly of polylactide (PLA)-based linear and graft copolymers. The PLA-based copolymers (PLA-Cs) were synthesized through a convenient one-pot/one-step ROP/RAFT technique. Three distinct vinyl monomers-triethylene glycol methacrylate (TEGMA), 2-hydroxypropyl methacrylate (HPMA), and N -(2-hydroxypropyl) methacrylamide (HPMAA) were employed to prepare various copolymers: linear thermoresponsive polylactide- b -poly(triethylene glycol methacrylate) (PLA- b -PTEGMA), graft pseudothermoresponsive poly[ N -(2-hydroxypropyl)] methacrylate- g -polylactide (PHPMA- g -PLA), and graft amphiphilic poly[ N -(2-hydroxypropyl)] methacrylamide- g -polylactide (PHPMAA- g -PLA). The MF technology was utilized for the controlled self-assembly of these PLA-based BCs in a solution, resulting in a range of nanoparticle (NP) morphologies. The thermoresponsive PLA- b -PTEGMA diblock copolymer formed thermodynamically stable micelles (Ms) through kinetically controlled assemblies. Similarly, employing MF channels led to the self-assembly of PHPMA- g -PLA, yielding polymersomes (PSs) with adjustable sizes under the same solution conditions. Conversely, the PHPMAA- g -PLA copolymer generated worm-like particles (Ws). The analysis of resulting nano-objects involves techniques such as transmission electron microscopy, dynamic light scattering investigations (DLS), and small-angle X-ray scattering (SAXS). More specifically, the thermoresponsive behavior of PLA- b -PTEGMA and PHPMA- g -PLA nano-objects is validated through variable-temperature DLS, TEM, and SAXS methods. Furthermore, the study explored the specific interactions between the formed Ms, PSs, and/or Ws with proteins in human blood plasma, utilizing isothermal titration calorimetry., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

In this report, monodisperse upconversion NaYF 4 :Yb 3+ /Er 3+ nanoparticles with superior optical properties were synthesized by the oleic acid-stabilized high-temperature co-precipitation of lanthanide chlorides in octadec-1-ene as a high-boiling organic solvent. To render the particles with biocompatibility and colloidal stability in bioanalytically relevant phosphate buffered saline (PBS), they were modified by using in-house synthesized poly(ethylene glycol)-neridronate (PEG-Ner), a bisphosponate. The NaYF 4 :Yb 3+ /Er 3+ @PEG nanoparticles showed excellent long-term stability in PBS and/or albumin without any aggregation or morphology transformation. The in vitro cytotoxicity of the nanoparticles was evaluated using primary fibroblasts (HF) and a cell line derived from human cervical carcinoma (HeLa). The particles were subsequently modified by using Bolton-Hunter-hydroxybisphosphonate to enable radiolabeling with 125 I for single-photon emission computed tomography/computed tomography (SPECT/CT) bimodal imaging to monitor the biodistribution of the nanoparticles in non-tumor mice. The bimodal upconversion 125 I-radiolabeled NaYF 4 :Yb 3+ /Er 3+ @PEG nanoparticles are prospective for near-infrared (NIR) photothermal/photodynamic and SPECT/CT cancer theranostics.

In this study, water-dispersed thermo-responsive boron nitride nanotubes (BNNTs) were prepared in a simple two-step process, where on the first step oligoperoxide was grafted via the interaction of amino groups (defects) of BNNTs with pyromellitic chloroanhydride fragments in oligoperoxide molecules. The second step involves N-isopropylacrylamide (NIPAM) graft polymerization 'from the surface' of oligoperoxide-functionalized BNNTs resulting in poly(N-isopropylacrylamide) (PNIPAM) coating. The pristine and functionalized BNNTs were characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometry, dynamic light scattering, scanning electron microscopy and atomic force microscopy. PNIPAM-functionalized BNNTs exhibit excellent dispersibility in water and possess thermo-responsive properties. The water-dispersion of thermo-responsive PNIPAM-functionalized BNNTs can help their potential use in biomedical applications as 'smart' surfaces, nanotransducers and nanocarriers.

In the current work, we present the successful functionalization and stabilization of P-25 TiO2 nanoparticles by means of N1,N7-bis(3-(4-tert-butyl-pyridium-methyl)phenyl)-4-(3-(3-(4-tert-butyl-pyridinium-methyl)phenylamino)-3-oxopropyl)-4-(3,4-dihydroxybenzamido)heptanediamide tribromide (1). The design of the latter is aimed at nanoparticle functionalization and stabilization with organic building blocks. On one hand, 1 features a catechol anchor to enable its covalent grafting onto the TiO2 surface, and on the other hand, positively charged pyridine groups at its periphery to prevent TiO2 agglomeration through electrostatic repulsion. The success of functionalization and stabilization was corroborated by thermogravimetric analysis, dynamic light-scattering, and zeta potential measurements. As a complement to this, the formation of layer-by-layer assemblies, which are governed by electrostatic interactions, by alternate deposition of functionalized TiO2 nanoparticles and two negatively charged porphyrin derivatives, that is, 5,10,15,20-(phenoxyacetic acid)-porphyrin (2) and 5,10,15,20-(4-(2-ethoxycarbonyl)-4-(2-phenoxyacetamido)heptanedioic acid)-porphyrin (3), is documented. To this end, the layer-by-layer deposition is monitored by UV/Vis spectroscopy, scanning electron microscopy, ellipsometry, and profilometry techniques. The resulting assemblies are utilized for the construction and testing of novel solar cells. From stable and repeatable photocurrents generated during several "on-off" cycles of illumination, we derive monochromatic incident photo-to-current conversion efficiencies of around 3 %., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)