Boosting the C2H2/CO2 Separation Performance of Metal-Organic Frameworks through Fluorine Substitution.

A pair of metal-organic frameworks (MOFs) of JXNU-15 (formulated as [Co6(µ3-OH)6(BTB)2(BPY)3]n, BTB3- = benzene-1,3,5-tribenzoate and BPY = 4,4'-bipyridine) and its fluorinated JXNU-15(F) ([Co6(µ3-OH)6(SFBTB)2(BPY)3]n) based on the fluorous 1,3,5-tri(3,5-bifluoro-4-carboxyphenyl)benzene (SFBTB3-) ligands were presented. The detailed comparisons of the acetylene/carbon dioxide (C2H2/CO2) separation abilities between the isostructural JXNU-15(F) and JXNU-15 were presented. In comparison with the parent JXNU-15, the higher C2H2 uptake, larger adsorption selectivity of the C2H2/CO2 (50/50) mixture, and enhanced C2H2/CO2 separation performance endow JXNU-15(F) with highly efficient C2H2/CO2 separation performance, which is demonstrated by singe-component gas adsorptions and dynamic gas mixture breakthrough experiments. The fluorine substituents exert the crucial effects on the enhanced C2H2/CO2 separation ability of JXNU-15(F) and play the dominant role in the C2H2-framework interactions, as uncovered by computational simulations. This work illustrates a powerful fluorine substitution strategy for boosting C2H2/CO2 separation ability for MOFs.

Enhancement of Propadiene/Propylene Separation Performance of Metal-Organic Frameworks by an Amine-Functionalized Strategy.

Here, a hexanuclear Co6(µ3-OH)6 cluster-based metal-organic framework (MOF), [Co6(µ3-OH)6(BTB)2(bpy)3]n (JXNU-15) (bpy = 4,4'-bipyridine), with the 1,3,5-tri(4-carboxyphenyl)benzene (BTB3-) ligand was synthesized for the challenging propadiene/propylene separation. The combination of a large pore volume and a suitable pore environment boosts the significantly high propadiene (C3H4) uptake (311 cm3 g-1 at 298 K and 100 kPa) for JXNU-15. An amine-functionalized MOF of JXNU-15(NH2) was further obtained with the 1,3,5-tri(4-carboxyphenyl)benzene analogue of 3,3″-diamino-5'-(3-amino-4-carboxyphenyl)-[1,1':3',1″-terphenyl]-4,4″-dicarboxylic ligand. The comparative studies of propadiene/propylene(C3H4/C3H6) separation performance between isostructural JXNU-15 and JXNU-15(NH2) are provided. JXNU-15(NH2) exhibits an impressive C3H4 capacity at low pressures with 69.1 cm3 g-1 at 10 kPa, which is twice that of JXNU-15 under the same conditions. Moreover, the separation selectivity of JXNU-15(NH2) is 1.3-fold higher as compared to JXNU-15. JXNU-15(NH2) with enhanced C3H4/C3H6 separation performance was elegantly illustrated by gas separation experiments and theoretical simulations. This work presents an amine-functionalized strategy for the enhancement of the C3H4/C3H6 separation performance of MOF.

Ω-Shaped fiber optic LSPR coated with hybridized nanolayers for tumor cell sensing and photothermal treatment.

Circulating tumor cell (CTC) in the blood is the main cause of cancer metastasis for death in cancer patients. It is extremely important for cancer diagnosis at an early stage and treatment to simultaneously detect and kill the CTCs. In this work, a new hybridized nanolayer, namely gold nanoparticle/gold nanorods@ Polydopamine (AuNPs/AuNRs@PDA), was coated on the Ω-shaped fiber optics (Ω-FO) for localized surface plasmonic resonance (LSPR) to perform tumor cell sensing and photothermal treatment (PTT). The PDA nanolayer was formed on a bare fiber optic through the self-polymerization of dopamine under mild conditions. The AuNRs and AuNPs were absorbed on the surface of the PDA nanolayer to form a hybridized nanolayer. The hybridized nanolayer-modified Ω-FO LSPR exhibited a high refractive index sensitivity (RIS) of 37.59 (a.u/RIU) and photothermal conversion efficiency. After being modified with the recognition element of aptamer, the Ω-FO LSPR was used to develop a sensitive and specifical tumor cell sensing. Under the irradiation of near-infrared light (NIR) laser, the Ω-FO LSPR can kill the captured tumor cells with the apoptotic/necrotic rate of 62.6 % and low side-effect for the nontarget cells. The FO LSPR sensor realized the dual functions of CTC sensing and PTT, which provided a new idea for the early diagnosis and treatment of cancer.

Sandwich Layer-Modified Ω-Shaped Fiber-Optic LSPR Enables the Development of an Aptasensor for a Cytosensing-Photothermal Therapy Circuit.

The metastasis of cancer cells is a principal cause of morbidity and mortality in cancer. The combination of a cytosensor and photothermal therapy (PTT) cannot completely eliminate cancer cells at one time. Hence, this study aimed to design a localized surface plasmonic resonance (LSPR)-based aptasensor for a circuit of cytosensing-PTT (COCP). This was achieved by coating a novel sandwich layer of polydopamine/gold nanoparticles/polydopamine (PDA/AuNPs/PDA) around the Ω-shaped fiber-optic (Ω-FO). The short-wavelength peak of the sandwich layer with strong resonance exhibited a high refractive index sensitivity (RIS). The modification with the T-shaped aptamer endowed FO-LSPR with unique characteristics of time-dependent sensitivity enhancement behavior for a sensitive cytosensor with the lowest limit of detection (LOD) of 13 cells/mL. The long-wavelength resonance peak in the sandwich layer appears in the near-infrared region. Hence, the rate of increased localized temperature of FO-LSPR was 160 and 30-fold higher than that of the bare and PDA-coated FO, indicating strong photothermal conversion efficiency. After considering the localized temperature distribution around the FO under the flow environment, the FO-LSPR-enabled aptasensor killed 77.6% of cancer cells in simulated blood circulation after five cycles of COCP. The FO-LSPR-enabled aptasensor improved the efficiency of the cytosensor and PTT to effectively kill cancer cells, showing significant potential for application in inhibiting cancer metastasis.

Incorporation of computed tomography and magnetic resonance imaging function into NaYF4:Yb/Tm upconversion nanoparticles for in vivo trimodal bioimaging.

Rational design and fabrication of multimodal imaging nanoprobes are of great significance for in vivo imaging. Here we report the fabrication of a multishell structured NaYF4:Yb/Tm@NaLuF4@NaYF4@NaGdF4 nanoprobe via a seed-mediated epitaxial growth strategy for upconversion luminescence (UCL), X-ray computed tomography (CT), and magnetic resonance (MR) trimodal imaging. Hexagonal phase NaYF4:Yb/Tm is used as the core to provide UCL, while the shell of NaLuF4 is epitaxially grown on the core not only to provide an optically inert layer for enhancing the UCL but also to serve as a contrast agent for CT. The outermost NaGdF4 shell is fabricated as a thin layer to give the high longitudinal relaxivity (r1) desired for MR imaging. The transition shell layer of NaYF4 not only provides an interface to facilitate the formation of NaGdF4 shell but also inhibits the energy transfer from inner upconversion activator to surface paramagnetic Gd(3+) ions. The fabricated multishell structured nanoprobe shows intense near-infrared UCL, high r1 value of 3.76 mM(-1) s(-1), and in vitro CT contrast effect. The multishell structured nanoprobe offers great potential for in vivo UCL/CT/MR trimodal imaging. Further covalent bonding of folic acid makes the multishell structured nanoprobe promising for in vivo targeted UCL imaging of tumor-bearing mice.

Dicopper(II) paddle-wheel metal-organic frameworks for high propyne storage under ambient conditions.

Fluorinated dicopper(II) metal-organic framework JXNU-16F with 1,3,5-tri(3,5-bifluoro-4-carboxyphenyl)benzene ligands and nonfluorinated JXNU-16 exhibit high propyne uptakes of 443 and 496 cm3 g-1 under ambient conditions, respectively. Their remarkable propyne uptakes result from suitable pore spaces and strong propyne⋯propyne interactions amongst the adsorbed propyne molecules, as revealed by computational simulations.

An engineered cascade-sensitized red-emitting upconversion nanoplatform with a tandem hydrophobic hydration-shell and metal-phenolic network decoration for single 808 nm triggered simultaneous tumor PDT and PTT enhanced CDT.

Near-infrared light (NIR) driven lanthanide-doped upconversion nanoparticle (UCNP) based photo-dynamic therapy (PDT) holds a great promise for the non-invasive treatment of deep-seated tumors. However, it has also been highly hindered by the low upconversion luminescence (UCL) efficiency, hypoxia nature of solid tumors, and low therapeutic efficiency using single modality. Herein, we present a novel Nd3+ → Yb3+ → Tm3+ → Er3+ cascade-sensitized red-emitting UCNP with tandem hydrophobic hydration-shell (HHS) and metal-phenolic network (Fe-tannic acid, Fe-TA) decoration (UCNP@HHS@Fe-TA, denoted as UCFS@Fe-TA) for single 808 nm triggered simultaneous tumor PDT and photothermal therapy (PTT) enhanced chemo-dynamic therapy (CDT). The UCNP can supply intense red emission under high tissue penetrating/minimized tissue overheating 808 nm excitation, and their HHS coating with perfluorocarbon/photosensitizer Ce6 co-doping can not only realize UCL-based PDT, but also strengthen PDT of as-formed UCFS via O2-carrying/UCL protection capacity of the HHS. Fe-TA coating can supply 808 nm triggered PTT, and the rise in temperature during PTT leads to enhanced Fenton catalytic activity of Fe-TA and faster ˙OH production rate of CDT to match with the real-timely released 1O2 in PDT. The as-designed UCFS@Fe-TA thus can achieve a single 808 nm triggered simultaneous PDT and PTT enhanced CDT, leading to a PTT-assisted reactive oxygen species storm for efficient tumor suppression. Such a design also renders the nanoplatform lower cell dark toxicity. In addition, the single excitation-triggered multimodal therapy mode might address the excitation wavelength mismatch issue in dual laser-triggered PTT/PDT mode. This study has therefore presented an efficient nanotherapeutic platform enabling synergistic multimodal tumor therapies with high biocompatibility.

MOF-coated upconversion nanoconstructs for synergetic photo-chemodynamic/oxygen-elevated photodynamic therapy.

Excessive production of intracellular reactive oxygen species (ROS) can induce apoptosis of cancer cells; however, it is often limited by severe triggering conditions and hypoxic microenvironments of solid tumors. To address these issues, herein, we have designed a MOF-coated upconversion nanoconstruct (UCTSCF, referring to UC@Ce6/TFS@mSiO2@MIL-100(Cu/Fe)) for synergetic photochemodynamic therapy (PCT)/oxygen-elevated photodynamic therapy (PDT). The MOF (MIL-100(Fe)) coating with Cu-doping was designed to catalyze H2O2 overexpression in cancer cells to generate the most cytotoxic ˙OH via chemodynamic therapy (CDT). It is noted that UC, representing 808 nm driven upconversion nanoparticles with high tissue penetration depth/low over-heating effects, was designed to provide intense blue light which can relieve the severe triggering conditions of CDT via PCT. Furthermore, the functional layer of the photosensitizer chlorin e6 (Ce6) and O2-carrying triethoxy(1H,1H,2H,2H-nonafluorohexyl)silane (TFS) co-doped mesoporous silicon (Ce6/TFS@mSiO2) can cause oxygen-elevated 1O2 production upon 671 nm light irradiation. In such a simple ROS generation nanoplatform, we heighten the antitumor effect via oxygen-elevated synergetic tumor PCT/PDT.

Revealing the in situ NaF generation balance for user-friendly controlled synthesis of sub-10 nm monodisperse low-level Gd3+-doped ß-NaYbF4:Er.

Herein, user-friendly control of the synthesis of sub-10 nm hexagonal (ß-) NaYbF4:Er nanocrystals (NCs) with extremely low-level Gd3+ doping (0%, 10 mol%) was achieved. We reveal for the first time that the effective sodium/fluoride levels during the formation of cubic (α-) nuclei are not only controlled by the sodium/fluoride to rare-earth precursor ratios used, but also sensitively restricted by the in situ NaF generation reaction in a sodium oleate-based solvothermal system. Excessive in situ NaF generation will lead to a respective sodium- and fluoride-deficient environment, delayed α-to-ß transition and larger ß-NCs. Based on these effects, sub-10 nm monodisperse low-level Gd3+-doped ß-NaYbF4:Er was obtained with a user-friendly low fluoride dosage by finely balancing this NaF generation reaction and achieving an intrinsic optimized sodium-fluoride level for NC nucleation. Notably, our work represents the first example where the focus is on the competing in situ NaF generation reaction and its use for nucleation regulation, as well as for the user-friendly control of the solvothermal synthesis of sub-10 nm ß-NaYbF4:Er.