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This work provides fascinating insights into NIR fluorophore design and methods to effectively alter the photophysical and morphological properties of the nanoaggregates for bio-imaging purposes.

Linear-dendritic block copolymers (LDBCs) have emerged as promising materials for drug delivery applications, with their hybrid structure exploiting advantageous properties of both linear and dendritic polymers. LDBCs have promising encapsulation efficiencies that can be used to encapsulate both hydrophobic and hydrophilic dyes for bioimaging, cancer therapeutics, and small biomolecules. Additionally, LDBCS can be readily functionalized with varying terminal groups for more efficient targeted delivery. However, depending on structural composition and surface properties, LDBCs also exhibit high dispersities (

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.

Thermal chemical synthesis of conjugated polymers has often been plagued by low product yields, by-product contamination and high-cost catalysts. Electrochemical synthesis is an alternative strategy that can overcome these failures to obtain highly efficient syntheses. Herein, we present the study of diketopyrrolopyrrole-bisthiophene (DPPT2), diketopyrrolopyrrole-bisfuran (DPPF2) and thienothiadiazole-bisthiophene (TTDT2) for diblock copolymerization with terthiophene (T3) as a π-linker to form tunable narrow band gap polymers. The polymers suspended as thin films have similar redox characteristics to the monomers with potential shifts that prove the identity of the respective polymers. Electrochemical impedance measurements were carried out in the −0.6 V to 1.0 V potential range with an average electron transport resistance (Re) value of 110 Ω irrespective of the applied potential. This confirms the polymers to have higher intrinsic electrical conductivity. The atomic ratios of the synthesized materials were calculated experimentally using energy dispersive X-ray (EDX) analysis, and they confirm the theoretical composition of the polymers. These doped polymers exhibit absorption bands in the visible to SWIR region (800–1800 nm) with optical band gaps from 0.773 to 1.178 eV in both the solid and the solution state.

The study of π-conjugated oligomers has garnered significant interest because of their use in organic optoelectronic devices, such as organic light-emitting diodes or organic field-effect transisto...

Shortwave infrared (SWIR) emission has great potential for deep-tissue in vivo biological imaging with high resolution. In this article, the synthesis and characterization of two new xanthene-based RosIndolizine dyes coded PhRosIndz and tolRosIndz is presented. The dyes are characterized via femtosecond transient absorption spectroscopy as well as steady-state absorption and emission spectroscopies. The emission of these dyes is shown in the SWIR region with peak emission at 1097 nm. TolRosIndz was encapsulated with an amphiphilic linear dendritic block co-polymer (LDBC) coded 10-PhPCL-G3 with high uptake yield. Further, cellular toxicity was examined in vitro using HEK (human embryonic kidney) cells where a >90% cell viability was observed at practical concentrations of the encapsulated dye which indicates low toxicity and reasonable biocompatibility.

Methanol and dichloromethane extracts of root, stem, leaves and flowers of invasive plant Austroeupatorium inulifolium were tested for cytotoxic, phytotoxic, antioxidant and antifungal activities. Significantly higher phytotoxicity was detected in methanol extracts of leaves and dichloromethane extracts of roots. This effect was most pronounced against amaranth seeds where the seed germination was reduced to 3.74 % with the addition of methanol extracts of leaves at 3000 mg/L. The dichloromethane extract of roots of A. inulifolium showed potent antifungal activity against Cladosporium cladosporioides . Cytotoxic activity was found in dichloromethane extract of roots (LD 50 = 27.91 ± 8.55 mg/L), methanol extract of flowers (LD 50 = 15.22±7.89 mg/L) and leaves (LD 50 = 22.92±11.76 mg/L) against Artemia salina (brine shrimp) larvae. The results also revealed significant antioxidant activity in methanol extract of leaves (IC 50 =33.66± 0.03 mg/L) against the reference α-tocopherol (IC 50 =10.02 ± 0.01 mg/L).