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Here, we present a new diacetoxy-functionalized UiO-66 metal-organic framework (MOF) for the trace level detection of hydrazine in water. The MOF material (1) was solvothermally prepared by the reaction between ZrOCl2·8H2O and 2,5-diacetoxy-1,4-benzenedicarboxylic acid (H2BDC-(OCOCH3)2). The desolvated material (1') showed a highly selective fluorescent turn-on signal towards hydrazine in water, which can be visualized by the naked eye under a UV lamp. Within 1 min of hydrazine addition, there was 14-fold fluorescence enhancement. The probe can detect hydrazine up to the nanomolar level (detection limit = 78.8 nM) in water. This detection limit is the lowest among MOF-based fluorescent probes for hydrazine. The material was also utilized for the sensing of hydrazine in paper strips and environmental water samples. Hydrazine-selective deprotection of ester groups anchored with the ligand is the principal reason behind the switch-on nature of sensing.

In this work, we present a Ag@Au nanoprism-metal-organic framework-paper based glucose sensor for rapid, sensitive, single-use and quantitative glucose determination in human serum. To achieve painless measurement of glucose with a non-invasive detection methodology, this biosensor was further tested in human urine. In this approach, a new hybrid-Ag@Au nanoprism loaded in close proximity to micrometer sized coordination polymers as phosphorescent luminophores significantly enhanced the emission intensity due to metal-enhanced phosphorescence and worked as reaction sites to support more dissolved oxygen. Reports of enhanced phosphorescence intensity are relatively rare, especially at room temperature. The true enhancement factor of Ag@Au-phosphorescent metal-organic frameworks on paper was deduced to be 110-fold, making it a better optical type glucose meter. The results demonstrate the validity of the intensity enhancement effect of the excitation of the overlap of the emission band of a luminophore with the surface plasmon resonance band of Ag@Au nanoprisms. Ag@Au nanoprisms were used not only to improve the detection limit of glucose sensing but also to extend the glucose sensing range by enhancing the oxygen oxidation efficiency. The oxidation of glucose as glucose oxidase is accompanied by oxygen consumption, which increases the intensity of the phosphorescence emission. The turn-on type paper-based biosensor exhibits a rapid response (0.5 s), a low detection limit (0.038 mM), and a wide linear range (30 mM to 0.05 mM), as well as good anti-interference, long-term longevity and reproducibility. Finally, the biosensor was successfully applied to the determination of glucose in human serum and urine.

Herein, we report the fast and selective detection of bilirubin by a recyclable Al(iii) based post-synthetically modified MIL-53 metal-organic framework (MOF) (1-NH2@THB). Post-synthetic modification was achieved by the aldimine condensation reaction between MIL-53-NH2 and 2,3,4-trihydroxy benzaldehyde. The post-synthetically modified compound was successfully characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) analysis and X-ray powder diffraction (XRPD) experiments. The material has huge potential to detect bilirubin in HEPES buffer medium (pH = 7.4) by a fluorescence "turn-off" mechanism. The drastic quenching in the fluorescence emission intensity of the MOF material in the presence of bilirubin is due to the inner filter effect as well as molecular interactions between the MOF material and bilirubin. The probe displayed ultra-fast response (30 s), low detection limit (1.26 pM) and high selectivity towards bilirubin with the co-existence of several metal ions and biomolecules. Moreover, the real field application of the probe was thoroughly investigated in human bio-fluids (blood serum and urine samples) by the standard addition method. Furthermore, the quenching ability of the MOF material by bilirubin was also explored on a portable paper strip device. All the above discussions indicate that the probe is a potential candidate for the clinical detection of jaundice.

Metal-organic frameworks (MOFs) have been broadly applied in biomedical and other fields. MOFs have high porosity, a large comparative area, and good biostability and have attracted significant attention, especially in cancer therapies. This paper presents the latest applications of MOFs in chemodynamic therapy (CDT), sonodynamic therapy (SDT), photodynamic therapy (PDT), photothermal therapy (PTT), immunotherapy (IT), and combination therapy for breast cancer. A combination therapy is the combination of two different treatment modalities, such as CDT and PDT combination therapy, and is considered more effective than separate therapies. Herein, we have also discussed the advantages and disadvantages of combination therapy in the treatment of breast cancer. This paper aims to illustrate the potential of MOFs in new cancer therapeutic approaches, discuss their potential advantages, and provide some reflections on the latest research results.

2,6-Pyridine dicarboxylic acid (DPA) is considered one of the main anthrax biomarkers, and the detection of DPA is of great significance. This work presents a Zn(II)-based metal-organic framework (MOF) with the formula {[Zn 2 (2,6-NBC) 2 (vlpy)Zn(2,6-NBC)(vlpy) 0.5 ]·0.8(2,6-H 2 NBC)·H 2 O} n (1) assembled from 2,6-naphthalenedicarboxylic acid (2,6-H 2 NBC) and 4,4'-vinylenedipyridine (vlpy) for a photoluminescence sensor matrix for DPA detection. 1 features a 3D pillar-layer framework with nanopore sizes of ca. 13.165 Å × 12.731 Å, 12.725 Å × 11.018 Å and 13.114 Å × 13.165 Å along the three directions, occupied by lattice water and disordered 2,6-H 2 NBC molecules. The obtained 1 can be used as a turn-on fluorescence sensor for the detection of DPA with high selectivity, excellent sensitivity and recyclability. The luminescence of 1 demonstrates an obvious color change from blue to purplish blue as the DPA concentration rises. Furthermore, a linear correlation is presented between the fluorescence and a low DPA concentration of 0-0.3 mM, and the detection limit can reach as low as 128 nM, much lower than that of an infectious dose to a human of anthrax spores (60 μM). A fluorescence test paper is fabricated to detect DPA rapidly through color change. DFT calculations indicate the intermolecular photoinduced electron-transfer transition and hydrogen-bonding interaction between DPA molecules and the skeleton of 1 induces the "turn-on" fluorescence sensing of DPA behavior.

We report the solvothermal synthesis of a dansyl anchored hafnium based fluorescent metal-organic framework (MOF) having the formula [Hf 6 O 4 (OH) 4 (L) 6 ]·H 2 O·6DMF (H 2 L = 2-((5-(dimethylamino)naphthalene)-1-sulfonamido)terephthalic acid). The synthesized material showed high fluorescence emission properties as well as high thermal (stable up to 330 °C) and chemical stability. It also exhibited a wide range of pH tolerance as well as a high BET surface area of 703 m 2 g -1 . The activated MOF showed ultra-fast (detection time < 10 s) and ultra-sensitive sensing properties towards Cu(II) and the biologically important biomarker 3-nitrotyrosine (3-NTyr) in a HEPES medium at a physiological pH of 7.4. Along with high selectivity, very low detection limits of 229 nM and 539 nM were obtained for Cu(II) and 3-NTyr respectively. Furthermore, this probe was utilised for the detection and quantification of Cu(II) and 3-NTyr in biosamples (urine and serum) with very low RSD values (2.3-4.8%). Additionally, this probe was employed to detect the presence of Cu(II) as a pollutant in various environmental water samples. Furthermore, for rapid economic detection of Cu(II), a MOF coated fluorescent paper strip was demonstrated. Thorough mechanistic investigations displayed that a complexometric interaction between Cu(II) and the probe is the main reason for the quenching of fluorescence intensity. This proposed mechanism was well supported by experimental evidence. On the other hand, the FRET mechanism is proposed based on the experimental observations for dynamic quenching of the fluorescence intensity of the probe in the presence of 3-NTyr.

We developed a porous diamino group-functionalized Zr(IV) metal-organic framework (MOF). The synthesized MOF has a similar structure to DUT-52 (DUT = Dresden University of Technology), which has a face-centered cubic structure with an Fm 3̄ m space group. The synthesized material (DUT-52-(NH2)2-1) was solvent exchanged with methanol (MeOH) and activated at 100 °C overnight. Both the as-synthesized and activated materials (DUT-52-(NH2)2-1') are thermally stable until 300 °C. The Brunauer-Emmett-Teller (BET) surface area of DUT-52-(NH2)2-1' was found to be 413 m 2 g -1 . DUT-52-(NH2)2-1' showed a significant quenching of fluorescence response after coming in contact with free chlorine (ClO - ) in an aqueous medium. The selectivity of DUT-52-(NH2)2-1' towards ClO - was not significantly hampered in the presence of any competitive ion. The limit of detection (LOD) value was found to be 0.08 μM in phosphate-buffered saline (PBS, pH = 7.4). DUT-52-(NH2)2-1' is recyclable and very sensitive towards ClO - . Moreover, the paper strip method was developed for onsite identification of ClO - . Furthermore, the catalytic activity of DUT-52-(NH2)2-1' was tested in the Knoevenagel condensation between benzaldehyde and cyanoacetamide. The experimental results clearly indicate that DUT-52-(NH2)2-1' exhibits high activity with very high selectivity towards condensation products. The solid was reusable three times with no decay in its activity, as evidenced by powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM) and fourier transform infrared (FT-IR).

Dipicolinic acid (DPA) is an anthrax biomarker. Its serious consequences make its detection a great need. In this paper, three novel metal-organic frameworks (MOFs) with different coordination modes were synthesized by a simple solvothermal method, which can be used as highly efficient fluorescence sensors for the highly selective and sensitive trace detection of DPA. MOFs 1-3 showed rapid responses to DPA (<30 s), and the limits of detection (LODs) were calculated to be 1.01 × 10 -6 M -1 (MOF 1), 1.17 × 10 -6 M -1 (MOF 2) and 2.07 × 10 -6 M -1 (MOF 3). DPA detection based on MOFs 1-3 in fetal bovine serum is highly reliable based on the high recovery rates (90% to 115%). Hence, the three MOF-based sensors can be used in the real-time detection of DPA.

Here, we present a 4-nitrophenyl functionalized Zr-UiO-66 MOF (MOF = metal-organic framework) and its applications towards the selective, sensitive and rapid detection of H 2 S both in the aqueous medium and vapour phase. The MOF material was synthesized using the 2-(nitrophenoxy)terepththalic acid (H 2 BDC-O-Ph-NO 2 ) linker and ZrCl 4 salt in the presence of a benzoic acid modulator. It was carefully characterized by thermogravimetric analysis (TGA), elemental analysis, powder X-ray diffraction (PXRD), FT-IR spectroscopy and surface area analysis. Noticeable thermal stability up to a temperature of 390 °C under air and the considerable chemical stability in different liquid media (H 2 O, 1 M HCl, glacial acetic acid, NaOH in the pH = 8 to 10 range) confirmed the robustness of the MOF. The BET surface area (1040 m 2 g -1 ) indicated the porous nature of the MOF. Remarkable selectivity of the MOF towards H 2 S over other potential congeners of H 2 S was observed in the aqueous medium. A very high fluorescence increment (∼77 fold) was observed after adding an aqueous Na 2 S solution to the MOF suspension. The MOF probe displayed the lowest limit of detection (12.58 nM) among the existing MOF-based chemosensors of H 2 S. Furthermore, it exhibited a very quick (60 s) response towards H 2 S detection. The MOF compound could also detect H 2 S in the vapour phase as well as in real water samples. Furthermore, we developed inexpensive MOF-coated paper strips for the naked-eye sensing of H 2 S. A thorough investigation was carried out in order to elucidate the fluorescence turn-on sensing mechanism.

Urgent demand for the prevention and diagnosis of physiological diseases is driving the development of biomarkers and physiological temperature fluorometric sensors. In this paper, a rare trinuclear lanthanide metal-organic framework (MOF), [(CH 3 ) 2 NH 2 ][Eu 3 (μ 3 -OH)(2,6-NDC) 3 (HCOO) 3 ]·(solv) x (Eu(2,6-NDC), where 2,6-H 2 NDC = 2,6-naphthalenedicarboxylic acid) was synthesized using reticular chemistry via reducing the symmetry of the organic ligand from axisymmetric 1,4-naphthalenedicarboxylic acid (1,4-H 2 NDC) to non-axisymmetric 2,6-H 2 NDC. Eu(2,6-NDC) shows exceptional chemical and thermal stability in acid-base solutions, PBS solution, and boiling water, and even under an air atmosphere up to 300 °C. As-synthesized Eu(2,6-NDC) exhibits ratiometric detection abilities for P 1 ,P 5 -di(adenosine-5') pentaphosphate (Ap5A), for use as a biomarker of dry eye disease, with a limit of detection (LOD) of 0.031 μM, as well as excellent anti-interference properties. As far as is known, it is the first Ap5A sensor based on MOFs. In addition, the results show that the ratiometric parameters of co-doped Eu 0.001 Gd 0.999 (2,6-NDC) deliver a good linear luminescence response to physiological temperatures (20-60 °C) with high sensitivity.

In this paper, we describe the facile preparation of a chiral catalyst by the combination of the amino acid, l-proline (Pro), and the enzyme, porcine pancreas lipase (PPL), immobilized on a microporous metal-organic framework (PPL-Pro@MOF). The multipoint immobilization of PPL onto the MOF is made possible with the aid of Pro, which also provided a chiral environment for enhanced enantioselectivity. The application of the microporous MOF is pivotal in maintaining the catalytic activity of PPL, wherein it prevented the leaching of Pro during the catalytic reaction, leading to the enhanced activity of PPL. The prepared biocatalyst was applied in asymmetric carbon-carbon bond formation, demonstrating the potential of this simple approach for chemical transformations.

The detection of pH and water is of significance in natural and production processes. The ionothermal reactions of 4,4'-oxybisbenzoic acid (H 2 OBA) with Eu 3+ and Tb 3+ produced [M(OBA)(H 2 O)Cl] (M = Eu 3+ (1) and Tb 3+ (2)) and heteronuclear [Eu 0.05 Tb 0.95 (OBA)(H 2 O)Cl] (3). 3 emits the combined characteristic transitions of Eu 3+ and Tb 3+ . Its energy transition processes can be disturbed by pH and water. The emission colors of 3 follow pH changes. It emits blue light when pH = 1-2, in which OBA 2- turns into H 2 OBA based on the acid-base equilibrium. When pH = 3-11, the emission colors change from green to orange and I Tb /I Eu exhibits a linearity of I Tb /I Eu = 6.7482-0.5971·pH; the emissions are quenched at pH = 12-13, due to OH - destroying the delocalized conjugated system of 3. 3 shows a fluorescence response to water with a linearity of I Tb /I Eu = 0.30353 + 0.15042·V H 2 O % within 0-0.8% V H 2 O %. The green (G) and red (R) color intensities of the paper-based MOF sensor of 3 reveal a trinomial fitting equation of G/R = 4.16334 - 1.23014·pH + 0.14036·pH 2 - 0.00551·pH 3 when pH = 3-11. 3 can be used as a ratiometric fluorescent sensor to detect pH and water and the paper-based MOF sensor can also be used in on-site pH detection.

Two-dimensional (2D) metal-organic framework (MOF) nanosheets have emerged as a new member of 2D nanomaterials for molecular sieving, energy conversion and storage, catalysis and biomedicine. In this paper, a highly dense assembly of porphyrin achievable in porphyrin-integrated MOF nanosheets induced by an ionic liquid is obtained by sonication exfoliation of its bulk crystals. The 2D layered structure MOF, [BMI]2[Ca3(H2TCPP)2(μ2-OH2)2(H2O)2] (1), was firstly prepared by using the ionic liquid assisted synthetic method (H6TCPP = meso-tetra(carboxyphenyl) porphyrin, BMI = 1-butyl-3-methylimidazolium). The laminated layers in 1 clearly indicate a weak interlayer non-covalent interaction but a strong metal-carboxylate bonding within the layers, which facilitates the exfoliation of 1 to form 2D MOF nanosheets (1 NSs). Powder X-ray diffraction (PXRD), high-resolution transmission electron microscopy (HR-TEM) and fast Fourier transform (FFT) patterns revealed that 1 NSs could maintain their crystalline structure after exfoliation. These MOF nanosheets exhibited excellent aqueous dispersibility, biodegradability and high cytotoxicity under light irradiation against MCF-7 cells.