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Hybrid Nanomaterials of Conjugated Polymers and Albumin for Precise Photothermal Therapy
摘要： Heretofore, conjugated polymers (CPs) attract considerable attention in photothermal therapy (PTT). Although various CPs with different structures have been reported, the suboptimal circulation persistence and biodistribution limit their efficacy in tumor treatment. Human serum albumin (HSA), an endogenous plasm protein, has been widely functioned as a carrier for therapeutic agents. Herein, we construct nanocomplexs C16 pBDP@HSA NPs from hydrophobic 4, 4-difluoro-4-bora-3a, 4adiaza-s-indacene (BODIPY)-containing CPs and HSA, which exhibit robust stability in physiological conditions and excellent photothermal activity upon irradiation. The high photothermal conversion efficiency of 37.5 %, higher than that of other reported PTT agents such as gold nanorods, phosphorus quantum dots and 2D materials, results in the potent photocytotoxicity towards cancer cells. Simultaneously, C16 pBDP@HSA NPs’ capabilities of near infrared fluorescence and photoacoustic imaging can provide guidance to the PTT. The outstanding inhibition of tumor growth results from great photothermal activity, the benefited accumulation in tumor and optimal timing of treatment. To the best of our knowledge, this is the first study which combines the BODIPY-based CPs and HSA in one nanostructure and finds application in cancer treatment. Moreover, this article also offers a new strategy for other insoluble macromolecules to explore more biomedical applications.
关键词： photothermal therapy,albumin,hybrid nanoparticles,conjugated polymers,BODIPY
更新于2025-09-09 09:28:46
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Torsionally induced exciton localization and decoherence in <i>π</i> -conjugated polymers
摘要： We develop a model of excitons coupled to the rotational motion of monomers to study the torsionally induced relaxation and decoherence of excitons in π-conjugated polymers. The model assumes that the monomer units are described by elastically uncoupled harmonic oscillators and that there is a linear exciton-roton coupling. Although the rotational degrees of freedom are much slower than the exciton, so that the adiabatic approximation is generally expected to be valid, we also investigate possible quantized roton corrections via coupled time evolving block decimation-Ehrenfest equations of motion. For the relaxation of the lowest-excited exciton, we find that (1) for a polymer chain with a ground state spiral torsional conformation, the equilibrium angular displacement of each monomer is proportional to the difference of the exciton bond-orders on the neighboring bridging bonds. Consequently, this displacement vanishes in the long chain limit and a classical (Landau) exciton-polaron is not formed. (2) For a polymer chain with a ground state staggered torsional conformation, the equilibrium angular displacement of each monomer is proportional to the sum of the exciton bond-orders on the neighboring bridging bonds. Consequently, there is significant angular displacement and local planarization causing exciton density localization. A classical (Landau) exciton-polaron is formed where the staggered angular displacement is proportional to the exciton density. (3) Generally, in the adiabatic limit, the decay of off-diagonal long-range order (i.e., exciton decoherence) mirrors the localization of the exciton density. However, quantum corrections to the rotational motion alter this adiabatic prediction because of correlated exciton-roton dynamics within the first rotational half-period. In particular, exciton-polaron quasiparticle formation causes more rapid and oscillatory exciton decoherence and slower exciton density localization.
关键词： π-conjugated polymers,exciton,decoherence,torsional relaxation,Landau exciton-polaron
更新于2025-09-04 15:30:14
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Pump-Push-Probe for Ultrafast All-Optical Switching: The Case of a Nanographene Molecule
摘要： In the last two decades, the three-beam pump–push–probe (PPP) technique has become a well-established tool for investigating the multidimensional configurational space of a molecule, as it permits disclosure of precious information about the multiple and often complex deactivation pathways of the excited molecule. From the spectroscopic point of view, such a tool has revealed details about the efficiency of charge pair generation and conformational relaxation in π-conjugated molecules and macromolecules. In addition, PPP is effectively utilized for modulating the gain signal in conjugated materials by taking advantage of the spectral overlap between stimulated emission and charge absorption in those systems. However, the relatively low stability of conjugated polymers under intense photoexcitation is a crucial limitation for their real employment in plastic optical fibers (POFs) and for signal control applications. Herein, the role of PPP for achieving ultrafast all-optical switching in π-conjugated systems is highlighted. Furthermore, new experimental data on optical switching of a newly synthesized nanographene molecule, namely dibenzo[hi,st]ovalene (DBOV), is reported. The superior environmental and photostability of DBOV and, in general, of graphene nanostructures can represent a great advantage for their effective applications in POFs and information and communications technology.
关键词： ultrafast optical switching,pump–push–probe,conjugated polymers,ultrafast spectroscopy,nanographene
更新于2025-09-04 15:30:14
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Synthesis and characterization of heterocyclic conjugated polymers containing planar Benzo[c]cinnoline and tetraazapyrene structures for organic field-effect transistor application
摘要： Heterocyclic conjugated polymers BZCTVT and TAPTVT containing tetraazapyrene (TAP) and benzo[c]cinnoline (BZC), respectively, were prepared by using Stille coupling polymerization in microwave reactor. TAP and BZC act as acceptors and thiophene-vinylene-thiophene (TVT) acts as donors. Alkylated thiophene is the linker between acceptor and donor. This is the first time that tetraazapyrene was incorporated into conjugated polymers. The films of BZCTVT and TAPTVT showed maximum absorption wavelength at 522 and 534 nm, respectively. From cyclic voltammertry measurement, TAPTVT and BZCTVT exhibited low LUMO (-3.61 and -3.47 eV) and HOMO (-5.64 and -5.63 eV) energy levels. Even though BZC and TAP were planar structures, BZCTVT and TAPTVT showed large dihedral angles between alkylated thiophene and TVT (10.8-22.6o), and between alkylated thiophene and BZC and TAP (22.2-30.3o) based on their simulated energy-minimized geometry. The bottom-gate, top-contact OFETs based on TAPTVT and BZCTVT exhibited only p-channel behavior with hole mobility of 4.63 × 10-4 and 1.04 × 10-4 cm2 V-1 s-1 and current on/off ratios greater than 104 after thermal annealing. Grazing incidence X-ray diffraction (GIXRD) patterns suggested that thin films of TAPTVT and BZCTVT preferred edge-on orientation.
关键词： heterocyclic conjugated polymers,organic field-effect transistor,tetraazapyrene,Stille coupling polymerization,benzo[c]cinnoline
更新于2025-09-04 15:30:14
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Electron Transport with Mobility, μ > 86 cm2/Vs, in a 74 nm Long Polyfluorene
摘要： The mobility of charges on conjugated polymers is a fundamentally important feature of these materials, but most fall far short of transport that might lead one to call them “molecular wires”. A commonly identified bottleneck is flexible dihedral angles between repeat units. Here we find a very high mobility, μ > 86 cm2/Vs, for electrons attached to polyfluorene polymers in isooctane, despite the presence of varied dihedral angles. The present data suggests that interactions with the surrounding medium may be a principal determinant of charge mobility.
关键词： mobility,molecular wires,conjugated polymers,polyfluorene,electron transport
更新于2025-09-04 15:30:14