To access smart optical theragnosis for cancer, an easily processable heterocyclic conjugated polymer (poly(sodium3‐((3‐methyl‐3,4‐dihydro‐2H‐thieno3,4‐b1,4dioxepin‐3‐yl)methoxy)propane‐1‐sulfonate), ...PPDS) nanoassembly is fabricated by a surfactant‐free one‐step process, without the laborious ordinary multicoating process. The conjugated nanoassembly, with a self‐doped structure, provides strong absorbance in the near‐infrared (NIR) range even in a neutral pH medium and exhibits excellent stability (>six months). In addition, the prepared PPDS nanoassembly shows a high photothermal conversion efficiency of 31.4% in organic photothermal nanoparticles. In particular, the PPDS nanoassembly is stably suspended in the biological medium without any additives. Through a simple immobilization with the anti‐CD44 antibody, the prepared biomarker‐targetable PPDS nanoassembly demonstrates specific targeting toward CD44 (expressed in stem‐like cancer cells), allowing NIR absorbance imaging and the efficient targeted photothermal damaging of CD44‐expressing cancer cells, from in vitro 3D mammospheres (similar to the practical structure of tumor in the body) to in vivo xenograft mice tumor models (breast cancer and fibrosarcoma). In this study, the most simplified preparation method is for this organic conjugated polymer‐based nanoassembly by a molecular approach is reported, and demonstrated as a highly promising optical nanoagent for optical cancer theragnosis.
A thiophene‐based photothermal (PT) organic nanoprobe is synthesized, with a simplified preparation process not requiring PEGylation or multicoating. The synthesized nanoassembly shows good stability, biocompatibility, and PT properties. The nanoassembly is applied to 3D tumor mammospheres and breast cancer, and shows excellent specific targeting of the CD44‐expressing cancerous cells, near‐infrared (NIR) absorbance imaging in vivo, and effective damaging by NIR light irradiation.
Well-defined fluorescent copolymers of methyl methacrylate with 1-pyreneylmethyl methacrylate were synthesized by atom transfer radical polymerization (ATRP). The random and block copolymer could be ...clearly distinguished by their glass-transition temperature (T g) values, with a single T g value (124 °C) for the random polymer, and two T g values (115 and 158 °C) for the block copolymer. The emission spectra of the copolymers were different in excimer emission, allowing analysis of the ordering of the two polymers, by determining the ratio between excimer emission (I E) and monomer emission (I M). The fluorescence spectra of the random copolymer exhibited both monomer and excimer emission of pyrene with a I E/I M ratio of 1.20−1.39 at a concentration of 0.001−0.05 mg/mL. The block copolymer exhibited strong excimer emission with an emission quantum yield for the excimer (ΦE) of 42%. The I E/I M ratio from the block copolymer was >25, even in a very dilute solution. The ΦE value increased to 68% when the block copolymer solution was processed to a thin film, indicating increased interactions among the pyrene block by self-assembly. In addition, nanopores were formed from the block copolymer, while no specific morphology was found from the random copolymer. The average diameter of the nanopores from block copolymer was ∼300 nm. Upon thermal annealing of the block copolymer film, a dramatic increase in excimer emission was observed to give a high ΦE value of 89%. A face-to-face pyrene assembly in the block copolymer was observed on the high-resolution transmission electron microscopy (HR-TEM) images, from which the average packing period of the well-defined pyrene block was estimated to range from 4.5 Å for pyrene block width to 5.6 Å for the width of PMMA mainchain.
A layer-by-layer (LBL) assembled electrochromic (EC) film was investigated by using poly(aniline-N-butylsulfonate)s (PANBS) as an electrochromic anionic polymer, and acid-doped polyaniline (PAN) and ...vinylbenzyldimethyl-n-octadecylammonium salts (VBOD) as a polycation. The layer sequence of the EC films was varied to optimize EC properties by changing the order of layer deposition. Electrochemical and electrochromic properties of EC films were highly dependent on the layer sequence. In the EC film composed alternatively of the PANBS/PAN and PANBS/VBOD bilayers (L1), higher redox current density was observed than that of the EC film composed conductive PANBS/ PAN layers. Furthermore, optical change (ΔOD) between the colored and the bleached state was largest in L1 among the EC films assembled in this study. This indicates that charge transport in L1 is more facile, reducing interlayer barrier (ILB) energy for charge transfer, possibly due to the flexible long alkyl chains of VBOD that may facilitate ion transport. An all-solid-state EC device based on an optimized LBL composition showed an EC response at 3 V within 1 s, with a stable memory effect.
Effective control of the morphology can enhance the performance of organic photovoltaics. The morphology of an active layer needs to have a large interfacial area between donors and acceptors for ...efficient exciton dissociation and continuous, direct charge transport paths to electrodes for high charge transport efficiency. These two requirements are usually contradictory. Here, we propose a morphology that meets these requirements nearly simultaneously, called an inter-diffused ordered bulk heterojunction (IDOBHJ). This novel structure exhibited 9% higher performance based on the Monte Carlo simulation than an optimized disordered bulk heterojunction. The main reasons for superior performance were attributed to the comparable short circuit current density and a higher fill factor. We also implemented the IDOBHJ morphology by the experimental nanoimprint technique combined with thermal annealing process to confirm simulation results. Our experimental results are indeed consistent with the theoretical analysis.
A polycyclic aromatic compound, anthracene, was covalently connected through a methylene bridge via Friedel–Crafts alkylation reaction. Thus, a highly fluorescent anthracene polymer (PMAn) linked by ...a methylene unit was prepared in one step to produce a conjugated–nonconjugated spacer-type polymer through its reaction with chloromethyl methyl ether (CME) and FeCl
3 at 0
°C. The resultant polymer was soluble in organic solvents and showed significantly higher fluorescence (quantum yield
=
0.80) compared to monomeric anthracene, 9-methylanthracene, in chloroform solution. Fluorescent thin films of PMAn as solid media were prepared with high film uniformity. The emission of the film was extinguished when the film was exposed to a UV source, due to the photodimerization of anthracene unit. A fluorescent gap electrode pattern was formed on the polymer film-forming average step depth of 8
nm and 14
nm, after 30 and 60
min irradiation with a UV light, respectively. The photo patternable fluorescent polymer afforded a convenient method of image formation and patterning.
A highly soluble poly(1,3,4‐oxadiazole) (POD) substituted with long alkyl chains was examined for electrochemical fluorescence switching. The high solubility of the polymers enabled a simple ...fabrication of an electrochemical cell, which showed reversible fluorescence switching between dark (n‐doping) and bright (neutral) states with a maximum on/off ratio of 2.5 and a cyclability longer than 1 000 cycles. Photochemical cleavage of the oxadiazole in POD allowed photo‐patterning of the POD film upon exposure to UV source. The patterned POD films displayed patterned image reversibly under a step potential of +1.8/−1.8 V.
A highly soluble poly(1,3,4‐oxadiazole) (POD) substituted with long alkyl chains showed reversible electrochemical fluorescence switching between dark (n‐doping) and bright (neutral) states. POD film was photo‐patterned to obtain high contrast secure images which displayed patterned image reversibly under a step potential of +1.8/−1.8V (vs. Ag/AgCl).
Recent observations that abiotic materials can engage in redox-based interactive communication motivates the search for new redox-active materials. Here we fabricated a hydrogel from a four-armed ...thiolated polyethylene glycol (PEG-SH) and the bacterial metabolite, pyocyanin (PYO). We show that: (i) the PYO-PEG hydrogel is reversibly redox-active; (ii) the molecular-switching and directed electron flow within this PYO-PEG hydrogel requires both a thermodynamic driving force (i.e., potential difference) and diffusible electron carriers that serve as nodes in a redox network; (iii) this redox-switching and electron flow is controlled by the redox network’s topology; and (iv) the ability of the PYO-PEG hydrogel to “transmit” electrons to a second insoluble redox-active material (i.e., a catechol-PEG hydrogel) is context-dependent (i.e., dependent on thermodynamic driving forces and appropriate redox shuttles). These studies provide an experimental demonstration of important features of redox-communication and also suggest technological opportunities for the fabrication of interactive materials.
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•Thiol-pyocyanin reaction was used to create a redox-active and interactive hydrogel•The electron flow and molecular switching requires diffusible mediators•These mediators and pyocyanin hydrogel serve as “nodes” in a redox reaction network•The networked flow of electrons between two separated hydrogels is reported
Bio-electrochemistry; Materials science; Polymers
As few mpox cases have been reported in Korea, we aimed to identify the characteristics of mpox infection by describing our epidemiologic investigation of a woman patient (index patient, the third ...case in Korea) and a physician who was infected by a needlestick injury (the fourth case).
We conducted contact tracing and exposure risk evaluation through interviews with these 2 patients and their physicians and contacts, as well as field investigations at each facility visited by the patients during their symptomatic periods. We then classified contacts into 3 levels according to their exposure risk and managed them to minimize further transmission by recommending quarantine and vaccination for post-exposure prophylaxis and monitoring their symptoms.
The index patient had sexual contact with a man foreigner during a trip to Dubai, which was considered the probable route of transmission. In total, 27 healthcare-associated contacts across 7 healthcare facilities and 9 community contacts were identified. These contacts were classified into high (7 contacts), medium (9 contacts), and low (20 contacts) exposure risk groups. One high-risk contact was identified as a secondary patient: a physician who was injured while collecting specimens from the index patient.
The index patient visited several medical facilities due to progressive symptoms prior to isolation. Although the 2022 mpox epidemic mainly affected young men, especially men who have sex with men, physicians should also consider mpox transmission in the general population for the timely detection of mpox-infected patients.
By loading Gd(III) inside NIR-absorbing polyaniline nanostructures, a novel diagnostic and photothermal agent with enhanced MR sensitivity, targeting ability, and photothermal ability to treat ...epithelial cancer is developed.
Catechols are abundant in nature and are believed to perform diverse biological functions that include photoprotection (e.g., melanins), molecular signaling (e.g., catecholamine neurotransmitters), ...and mechanical adhesion (e.g., mussel glue). Currently, the structure-property-function relationships for catechols remain poorly resolved, and this is especially true for redox-based properties (e.g., antioxidant, pro-oxidant, and radical scavenging activities). Importantly, there are few characterization methods available to probe the redox properties of materials. In this review, we focus on recent studies with redox-active catechol-chitosan films. First, we describe film fabrication methods to oxidatively-graft catechols to chitosan through chemical, enzymatic, or electrochemical methods. Second, we discuss a new experimental characterization method to probe the redox properties of catechol-functionalized materials. This mediated electrochemical probing (MEP) method probes the redox-activities of catechol-chitosan films by: (i) employing diffusible mediators to shuttle electrons between the electrode and grafted catechols; (ii) imposing tailored sequences of input voltages to "tune" redox probing; and (iii) analyzing the output current response characteristics to infer properties. Finally, we demonstrate that the redox properties of catechol-chitosan films enable them to perform antioxidant radical scavenging functions, as well as a pro-oxidant (reactive oxygen-generation) antimicrobial functions. In summary, our increasing knowledge of catechol-chitosan films is enabling us to better-understand the functions of catechols in biology as well as enhancing our capabilities to create advanced functional materials.
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