Lanthanide MOF-based luminescent sensor arrays for the detection of castration-resistant prostate cancer curing drugs and biomarkers

In recent years, castration-resistant prostate cancer (CRPC) has profoundly impacted the lives of many men, and early diagnosis of medication and illness is crucial. Therefore, a highly efficient detection method for CRPC biomarkers and curing drugs is required. However, the complex and diverse structures of CRPC drugs pose significant challenges for their detection and differentiation. Lanthanide metal–organic frameworks (Ln-MOFs) show great potential for sensing applications due to their intense and characteristic luminescence. In this work, a series of new bimetallic Ln-MOFs (EuxTb1−x-MOF) based luminescent sensor arrays have been developed to identify CRPC drugs, including in mixtures, via principal component analysis (PCA) and hierarchical cluster analysis (HCA) methods. These Ln-MOFs are built with a highly conjugated H2L linker (H2L = 5-(4-(triazole-1-yl)phenyl)isophthalic acid) and exhibit robust strong luminescence emissions (mainly located at 543 and 614 nm) and high energy transfer efficiencies. More specifically, Eu0.096Tb0.904-MOF (MOF 3) has demonstrated good sensing performances for CRPC curing drugs in real human serum samples. Furthermore, the curing drug hydroxyflutamide has been combined with MOF 3, to construct a robust composite sensing platform MOF 3@hydroxyflutamide for highly efficient detection of CRPC biomarkers such as the androgen receptor (AR) and prostate-specific antigen (PSA). Finally, luminescence lifetime measurements, zeta potential measurements, and density functional theory (DFT) calculations were performed to gain insights into the sensing mechanism.


General methods
The H2L Ligand was purchased from JiNan Henghua (Jinan, China).DNA sequences were purchased from AZENTA company.All the other reagents were commercially purchased and utilized without further purification.C, H, and N microanalyses were carried out with a Perkin-Elmer 240 elemental analyzer.Powder X-Ray Diffraction (PXRD) was characterized by a highthroughput Bruker D8 Advance diffractometer working on transmission mode and equipped with a focusing Göbel mirror producing CuKα radiation (λ = 1.5418Å) and a LynxEye detector.FT-IR spectra (4000-500 cm -1 ) were recorded by using a Nicolet iS5 FTIR ThermoFisher spectrometer.Ultrasonic preparation was carried by a Branson Ultrasonic bath (sonifier sound enclosure Instrument, USA).Agilgent technologies (USA) cary 300 spectrophotometer was utilized to record ultraviolet-visible (UV-vis) adsorption spectra.The photo-luminescent spectra were performed using a Fluorolog-3, Horiba Jobin Yvon (USA).TEM, STEM-HAADF, and EDS images were recorded with Thermo Fisher Scientific Talos F200X (USA), spot size of the beam used for TEM-EDS imaging is 6.
Electronic Supplementary Material (ESI) for Chemical Science.This journal is © The Royal Society of Chemistry 2024 Lifetime experiments were done using 10 mm path length quartz cuvettes: The ns fluorescence decay curves were obtained by the time-correlated single-photon counting (TCSPC) method.The setup is composed with a titanium sapphire Ti:Sa oscillator (Spectra Physics, Maï Taï HP) emitting pulses of 100 fs duration at 690nm, 80MHz frequency.The laser pulses then pass through a pulse picker which implements acousto-optic modulator to pick up specific pulse to reduce the repetition rate at 4MHz (GWU Lasertechnik, UHG-23-PSK).Then the beam, after adjusting the excitation power and the polarization with respectively an intensity attenuator filter wheel and a Fresnel rotator, passes through the sample solution.Fluorescence photons were detected at 90° through a long pass filter (Schott, RG9), a monochromator (CVI Laser Corporation, Digikröm CM110) and a polarizer by means of a micro channel plate photomultiplier (Hamamatsu, MCP-PMT R3809U-50), connected to a TCSPC module (Becker & Hickl,.Time-correlated fluorescence decay data is finally processed and analysed with the help of a software which implements the non-linear square method (Globals, Laboratory for Fluorescence Dynamics at the University of Illinois at Urbana-Champaign).The Absolute quantum yield test of MOFs 1-4 were measured on a SPEX Fluoromax-3 (Horiba Jobin-Yvon) equipped with an integrating sphere of 10 cm diameter and a Horiba Jobin-Yvon acquisition and analysis procedure.Quantum yields were calculated using equation (1), where the subscript with "0" and "x" stand for the corresponding parameter for the standard and sample and F, A, S and n represents the quantum yield, absorbance, integrated photoluminescence intensity and refractive index, respectively.For this measurement, the excitation position is 260 nm and the emission range is from 535 nm to 620nm.Zeta potential measurements were performed on Nano-ZS, Worcestershire, (Malvern, UK).MilliQ water was obtained from Millipore system.TGA data were collected on Mettler Toledo TGA/DSC 2, STAR System apparatus with a heating rate of 5 °C/min under the oxygen flow.ICP analysis were carried by Agilent 7700 Series ICP-MS, USA.Equation 1:
The structures were analyzed by direct methods and refined with the full-matrix least-squares method utilizing the SHELXS-97 and SHELXL-97 programs.Anisotropic thermal parameters were assigned to all non-hydrogen atoms.Organic hydrogen atoms were defined geometrically.
Analytical expressions of neutral-atom scattering factors were utilized and anomalous dispersion corrections were incorporated.Crystallographic data and refinement details for 1 and 2 were summarized in Table S1, selected bond lengths and angles were summarized in

Preparation of Eu0.096Tb0.904-MOF (3).
A mixture of Europium chloride (2.7 mg, 40.1 nmol), Terbium chloride (53.1 mg, 0.2 mmol) and H2L (46.2 mg, 0.15 mmol) was added into the mixture of DMF (1 mL) and H2O (0.7 mL).The mixed solutions were sealed in a 25 mL Teflon reactor, after the reaction mixture was heated at 120 °C for one day and then cooled to room temperature naturally, colorless bulky crystals of 3 were isolated in 63 % yield based on H2L ligand.The product was washed with ethanol to exchange residual DMF solvent molecules in the pores of Ln-MOF and then dried in a vacuum oven to volatilize all the solvent traces.
The mixed solutions were sealed in a 25 mL Teflon reactor, after the reaction mixture was heated at 120 °C for one day and then cooled to room temperature naturally, colorless bulky crystals of 4 were isolated in 66 % yield based on H2L ligand.The product was washed with ethanol to exchange residual DMF solvent molecules in the pores of Ln-MOF and then dried in a vacuum oven to volatilize all the solvent traces.

Preparation of Eu0.011Tb0.989-MOF (5).
A mixture of Europium chloride (0.732 mg, 0.002 mmol), Terbium chloride (13 mg, 0.19 mmol) and H2L (31 mg, 0.1 mmol) was added into the mixture of DMF (2 mL) and H2O (0.7 mL).The mixed solutions were sealed in a 25 mL Teflon reactor, after the reaction mixture was heated at 120 °C for one day and then cooled to room temperature naturally, colorless bulky crystals of 5 were isolated in 55 % yield based on H2L ligand.The product was washed with ethanol to exchange residual DMF solvent molecules in the pores of Ln-MOF and then dried in a vacuum oven to volatilize all the solvent traces.

Preparation of Eu0.415Tb0.585-MOF (6).
A mixture of Europium chloride (36.6 mg, 0.1 mmol), Terbium chloride (37.3 mg, 0.1 mmol) and H2L (31 mg, 0.1 mmol) was added into the mixture of DMF (2 mL) and H2O (0.7 mL).The mixed solutions were sealed in a 25 mL Teflon reactor, after the reaction mixture was heated at 120 °C for one day and then cooled to room temperature naturally, colorless bulky crystals of 6 were isolated in 45 % yield based on H2L ligand.The product was washed with ethanol to exchange residual DMF solvent molecules in the pores of Ln-MOF and then dried in a vacuum oven to volatilize all the solvent traces.

Preparation of Eu0.516Tb0.484-MOF (7).
A mixture of Europium chloride (13 mg, 0.05 mmol), Terbium chloride (13 mg, 0.05 mmol) and H2L (15.4 mg, 0.05 mmol) was added into the mixture of DMF (2 mL) and H2O (0.7 mL).The mixed solutions were sealed in a 25 mL Teflon reactor, after the reaction mixture was heated at 120 °C for one day and then cooled to room temperature naturally, colorless bulky crystals of 7 were isolated in 55 % yield based on H2L ligand.The product was washed with ethanol to exchange residual DMF solvent molecules in the pores of Ln-MOF and then dried in a vacuum oven to volatilize all the solvent traces.

Figure.
Figure.S5 (a) Luminescence spectra of 3 after adding Hydroxyflutamide at different concentrations (excitation: 250 nm); (b) linear relationship between concentration of Hydroxyflutamide and relative luminescence intensity ratio of 3.

Figure.
Figure.S9 (a) Luminescence spectra of 3 with Hydroxyflutamide (10 µM) after adding different concentrations of PSA (excitation: 250 nm); (b) the relationship between luminescent ratio of 3 and the concentration of PSA.

Figure.
Figure.S10 (a) Luminescence spectra of 3 with (10 µM) after adding different concentrations of AR (excitation: 250 nm); (b) the relationship between luminescent ratio of 3 and the concentration of AR.

Figure.
Figure.S11 Zeta potentials of MOF 3, hydroflutamide, and the mixture of the MOF 3 with hydroxyflutamide and specific antigen and androgen receptor.

Figure.
Figure.S12 Raman spectra of (a) PSA under different condition; (b) AR under different condition.

Figure.
Figure.S15.The luminescence decays of (a) MOF 3@Hydroxyflutamide (emission at 350 nm) after adding different concentrations of PSA; and (b) MOF 3@Hydroxyflutamide (emission at 350 nm) after adding different concentrations of AR.All the experiments were performed at λex= 260 nm.