This study represents a successful approach toward employing polycaprolactone–polyamidoamine (PCL–PAMAM) linear dendritic block copolymer (LDBC) nanoparticles as small-molecule carriers in NIR imaging and photothermal therapy. A feasible and robust synthetic strategy was used to synthesize a library of amphiphilic LDBCs with well-controlled hydrophobic-to-hydrophilic weight ratios. Systems with a hydrophobic weight ratio higher than 70% formed nanoparticles in aqueous media, which show hydrodynamic diameters of 51.6 and 96.4 nm. These nanoparticles exhibited loading efficiencies up to 21% for a hydrophobic molecule and 64% for a hydrophilic molecule. Furthermore, successful cellular uptake was observed via trafficking into endosomal and lysosomal compartments with an encapsulated NIR theranostic agent (C3) without inducing cell death. A preliminary photothermal assessment resulted in cell death after treating the cells with encapsulated C3 and exposing them to NIR light. The results of this work confirm the potential of these polymeric materials as promising candidates in theranostic nanomedicine.

Herein, we present a facile and comprehensive synthetic methodology for the preparation of polyester‐polyamidoamine (PAMAM) (i.e., polyester: polylactide [PLA] (hydrophobic) and polyamidoamine, PAMAM [hydrophilic]) polymers. A library of PLA‐PAMAM linear dendritic block copolymers (LDBCs) in which both l and d, l polylactide were employed in mass ratios of 30:70, 50:50, 70:30, and 90:10 (PLA:PAMAM) were synthesized and analyzed. When placed in aqueous media, the immiscibility of the hydrophilic and hydrophobic segments leads to nanophase‐segregation exhibited as the formation of aggregates (e.g., vesicles, worms, and/or micelles). By employing both stereochemical configurations of PLA, the differentiation in mass ratios of PLA‐PAMAM aided in elucidating the structure–property relationships of the LDBC system and provided a means toward the control of nanoparticle morphology. Transmission electron microscopy and dynamic light scattering afford the size and shape of the nanoparticles with diameters ranging from 10.6 for low mass ratios to 122.4 nm for high mass ratios of PLA‐PAMAM and positive zeta‐potential values between +24.7 mV and +48.2 mV. Furthermore, small‐angle X‐ray scattering (SAXS) studies were employed to obtain more detailed information on the morphological assemblies constructed via direct dissolution. Such insights provide a pathway toward nanomaterials with unique morphologies and tunable properties deemed relevant in the development of next generation biomaterials. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1448–1459

The effects of intermolecular interactions by a series of haloaromatic halogen bond donors on the normal modes and chemical shifts of the acceptor pyrimidine are investigated by Raman and NMR spectroscopies and electronic structure computations. Halogen-bond interactions with pyrimidine's nitrogen atoms shift normal modes to higher energy and upfield shift H and C NMR peaks in adjacent nuclei. This perturbation of vibrational normal modes is reminiscent of the effects of hydrogen bonded networks of water, methanol, or silver on pyrimidine. The unexpected observation of vibrational red shifts and downfield C NMR shifts in some complexes suggests that other intermolecular forces such as π interactions are competing with halogen bonding. Natural bond orbital analyses indicate a wide range of charge transfer is possible from pyrimidine to different haloaromatic donors and computed halogen bond binding energies can be larger than a typical hydrogen bond. These results emphasize the importance in strategic selection of substituents and electron withdrawing groups in developing supramolecular structures based on halogen bonding.

This study summarizes the synthesis, characterization, and evaluation of a library of biocompatible selfassembling Janus dendrimers (JDs) and their resulting nanostructures possessing either a cationic (NH 3 +), anionic (COO À), or neutral (OH) surface. Strategically designed for applications in therapeutic delivery, the dendrimers are comprised of a polyamidoamine (PAMAM) dendron as the hydrophilic portion and fatty acid (FA) functionalized dendrons as the hydrophobic portion. The physicochemical characterization and in vitro cell viability of amphiphilic JDs were performed. Microscopy (TEM) and dynamic light scattering (DLS) analysis indicate the size (i. e., diameters) of spherical nanoaggregates ranging from 40 to 100 nm with zeta-potential values ranging from À 17.9 to + 58.7 mV with respect to the terminal functional group of the JD employed. Furthermore, these systems exhibited spherical nanoaggregates with critical aggregate concentrations (CAC) ranging from 2.8 to 7.0 mg/L. At low concentrations (< 200 μg/mL), JDs nanoaggregates showed minimal cell growth inhibitory properties in the in vitro testing, demonstrating their safety. The results of this study prove that a simple yet strategic combination of chemically distinctive dendritic segments can afford a versatile library of unique JDs nanoplatforms with excellent potential for biomedical applications.

Here, we demonstrate the applicability of self‐assembling linear‐dendritic block copolymers (LDBCs) and their nanoaggregates possessing varied surfaces as therapeutic nanocarriers. These LDBCs are comprised of a hydrophobic, linear polyester chemically coupled to a hydrophilic dendron polyamidoamine (PAMAM)—the latter of which acts as the surface of the self‐assembled nanoaggregate in aqueous media. To better understand how surface charge density affects the overall operability of these nanomaterials, we modified the nanoaggregate surface to yield cationic (NH3+), neutral (OH), and anionic (COO−) surfaces. The effect of these modifications on the physicochemical properties (i.e., size, morphology, and surface charge density), colloidal stability, and cellular uptake mechanism of the polymeric nanocarrier were investigated. This comparative study demonstrates the viability of nanoaggregates formed from PDLLA‐PAMAM LDBCs to serve as nanocarriers for applications in drug delivery.

Rhodamine dyes are known for their excellent photoluminescence properties but not commonly known for their electrical conductivity or redox stability. They are usually found as pendants (sidechains) attached to a...

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The Inside Cover picture highlights perturbations to vibrational energy levels and 13C NMR spectra of the acceptor pyrimidine upon complexation with halogen bond donors. Shifts and interaction energies increase with stronger electron withdrawing groups and more polarizable halogen atoms. More information can be found in the Full Paper by D. L. Watkins, G. S. Tschumper, N. I. Hammer, and co‐workers on page 1267 in Issue 10, 2017 (DOI: 10.1002/cphc.201700114).