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Due to the difficulty of accurately characterizing properties such as the molecular weight (Mn) and grafting density (σ) of gradient brushes (GBs), these properties are traditionally assumed to be uniform in space to simplify analysis. Applying a stochastic reaction model (SRM) developed for heterogeneous polymerizations, we explored surface-initiated polymerizations (SIPs) with initiator gradients in lattice Monte Carlo simulations to examine this assumption. An initial exploration of SIPs with 'homogeneously' distributed initiators revealed that increasing σ slows down the polymerization process, resulting in polymers with lower molecular weight and larger dispersity (Đ) for a given reaction time. In SIPs with an initiator gradient, we observed that the properties of the polymers are position-dependent, with lower Mn and larger Đ in regions of higher σ, indicating the non-uniform properties of polymers in GBs. The results reveal a significant deviation in the scaling behavior of brush height with σ compared to experimental data and theoretical predictions, and this deviation is attributed to the non-uniform Mn and Đ. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR)-responsive hydrogels have exhibited remarkable advantages in biomedical applications especially for in situ therapeutic delivery, because of their deep-tissue penetration capacity, minimal invasiveness, and high spatiotemporal selectivity. Nevertheless, conventional NIR-responsive nanocomposite hydrogels suffer from the disadvantages of limited photothermal effect and potential leakage of the physically mixed photothermal nanoagents. To overcome these limitations, we herein designed an injectable thermosensitive photothermal-network hydrogel (PNT-gel) through the host-guest self-assembly of a photothermal conjugated polymers and ɑ -cyclodextrin. The conjugated-polymer backbones can directly convert incident light into heat, endowing the PNT-gel with high photothermal conversion efficiency (η = 52.6%) and enhanced photothermal stability. Meanwhile, the mild host-guest assembly enable the shear-thinning injectability, photothermally-driven and reversible gel-sol conversion of the hydrogel. Consequently, the remotely controlled on-demand release of doxorubicin (DOX) was achieved via photothermal-induced gel-sol transition. Because the backbone of the hydrogel absorbs NIR light and mediates the photothermal conversion itself, the PNT-gel demonstrated the advantage of a prolonged retention time and thus permitting repeatable NIR treatment after a one-time intratumoral injection of this hydrogel. Under repeated NIR laser irradiation (0.15 W cm−2), the synergistic photothermal-chemotherapy mediated by the PNT-gel almost completely eradicated 4T1 breast cancer. This work not only presents a multifunctional therapeutic platform integrated with inherent photothermal characteristic and reversible stimuli responsiveness for on-demand delivery and combinatorial photothermal-chemotherapy, but also provides a new strategy for the development of the next-generation of light-modulated intelligent hydrogels. The conventional NIR-responsive nanocomposite hydrogels suffer from the disadvantages of limited photothermal effect and possible leakage of the physically mixed photothermal nano-components. To overcome these limitations, we hereby fabricated a NIR-responsive themosensitive photothermal-network hydrogel through the supramolecular assembly of conjugated polymer. The conjugated polymeric backbones of the hydrogel directly convert NIR light to heat, endowing the hydrogel with good photothermal effect and long-term photothermal stability. Meanwhile, the dynamic crosslinkages via supramolecular assembly enabled the shear-thinning injectability and reversible gel-sol transition of the hydrogel, facilitating the photothermal-induced drug release. Our strategy demonstrated the efficacy of using conjugated polymer as the backbone of hydrogel for the construction of a new injectable NIR-responsive hydrogel system with enhanced photothermal capabilities and improved therapy outcomes. [ABSTRACT FROM AUTHOR]

The shallow penetration depth of photothermal agents in the first near-infrared (NIR-I) window significantly limits their therapeutic efficiency. Multifunctional nanotheranostic agents in the second near-infrared (NIR-II) window have drawn extensive attention for their combined treatment of tumors. Here, for the first time, we created oxygen-deficient black SnO 2-x with strong NIR (700-1200 nm) light absorption with NaBH 4 reduction from white SnO 2 . Hyaluronic acid (HA) could selectively target cancer cells overexpressed CD44 protein. After modification with HA, the obtained nanotheranostic SnO 2-x @SiO 2 -HA showed high dispersity in aqueous solution and good biocompatibility. SnO 2-x @SiO 2 -HA was confirmed to simultaneously generate enough hyperthermia and reactive oxygen species with single NIR-II (1064 nm) light irradiation. Because HA is highly affined to CD44 protein, SnO 2-x @SiO 2 -HA has specific uptake by overexpressed CD44 cells and can be accurately transferred to the tumor site. Furthermore, tumor growth was significantly inhibited following synergistic photodynamic therapy (PDT) and photothermal therapy (PTT) with targeted specificity under the guidance of photoacoustic (PA) imaging using 1064 nm laser irradiation in vivo. Moreover, SnO 2-x @SiO 2 -HA accelerated wound healing. This work prominently extends the therapeutic utilization of semiconductor nanomaterials by changing their nanostructures and demonstrates for the first time that SnO 2-x based therapeutic agents can accelerate wound healing. STATEMENT OF SIGNIFICANCE: The phototherapeutic efficacy of nanotheranostics by NIR-I lightirradiation was restricted owing to the limitation of tissue penetration and maximum permissible exposure. To overcome these limitations, we hereby fabricated a NIR-IIlight-mediated multifunctional nanotheranostic based on SnO 2 -x. The introduction of oxygen vacancy strategy was employed to construct full spectrum responsive oxygen-deficient SnO2-x, endowing outstanding photothermal conversion, and remarkable production activity of reactive oxygen species under NIR-II light activation. Tumor growth was significantly inhibited following synergistic PDT/PTT with targeted specificity under the guidance of photoacoustic imaging using 1064 nm laser irradiation in vivo. Our strategy not only expands the biomedical application of SnO 2 , but also providea method to develop other inorganic metal oxide-based nanosystems for NIR-II light-activated phototheranostic of cancers., Competing Interests: Declaration of Competing Interest We declare that we have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier Ltd.)

In the title compound, [Zn(C(5)H(5)N(2)O(2)S)(2)(H(2)O)], the central Zn atom (2 site symmetry) is five-coordinated by two N and three O atoms [Zn-N = 2.047 (3) Å, Zn-O = 2.099 (2) and 1.974 (4) Å] in a distorted square-pyramidal geometry. Besides one O atom from a water mol-ecule, two 2-amino-thia-zole-4-acetate ligands provide two N and two O atoms as coordinated atoms. In the crystal structure, inter-molecular O-H⋯O and N-H⋯O hydrogen bonds connect the mol-ecules into an infinite three-dimensional framework.

The title compound, (C(10)H(10)N(2))[Cu(C(2)O(4))(2)] or (4,4'-H(2)bpy)[Cu(ox)(2)] (bpy is 4,4'-bipyridine and ox is oxalate), is an ion-pair complex comprising a protonated 4,4'-bipyridinium dication and a square-planar dioxalatocopper(II) dianion. In the centrosymmetric dianion, the Cu(II) centre is coordinated by four O atoms from the two dicrete oxalate ligands [Cu-O = 1.9245 (19) and 1.9252 (17) Å], while the planar dications are also centrosymmetric. Inter-species N-H⋯O hydrogen bonds link the cations and anions into one-dimensional chains and, together with weak intra-ion C-H⋯O inter-actions, give a two-dimensional sheet structure.

In the title complex, [Ag(C(7)H(10)N(2)O(2)S)(2)]NO(3), the Ag(I) cation is bicoordinated in an almost linear configuration by two N-donor atoms of the thia-zole rings of two distinct ethyl 2-amino-4-thia-zoleacetate (EATA) ligands. The dihedral angle between the two thia-zole rings is 49.9°. A weak Ag⋯O (2.729 Å) inter-action between the Ag cation and one of the O atoms from the nitrate anion is observed, and a pseudo-dimer is formed through a weak Ag⋯S (3.490 Å) inter-action between the Ag cation and the S atom of the thia-zole ring of a symmetry-related mol-ecule. In the crystal structure, there are intra- and inter-molecular N-H⋯O hydrogen bonds. The occurrence of inter-molecular N-H⋯O hydrogen bonds results in the formation of two-dimensional sheets parallel to (010), which are further linked into a three-dimensional network through weak C-H⋯O inter-actions.

In the title compound, [CdCl(2)(C(4)H(6)N(2)S)(2)], the Cd(II) atom is coordinated by two chlorido ligands and two N atoms of the 2-amino-5-methyl-1,3-thia-zole (amtz) ligands in a slightly distorted tetra-hedral coordination geometry. Intra- and inter-molecular N-H⋯Cl hydrogen bonding stabilizes the crystal structure. A weak S⋯Cl inter-action [3.533 (2) Å] is observed between neighboring mol-ecules.