Disordered Convolution Region of P(VDF-TrFE) Piezoelectric Nanoparticles: The Core of Sono-Piezo Dynamic Therapy

The recent focus on P(VDF-TrFE) material in biomedical engineering stems from its outstanding mechanical properties and biocompatibility. However, its application in sono-piezo dynamic therapy (SPDT) has been relatively unexplored. In this study, we developed composite piezoelectric nanoparticles (rPGd NPs@RGD) based on recrystallized P(VDF-TrFE) particles, which offer dual capabilities of MRI imaging and targeted treatment for brain gliomas. SEM observations of P(VDF-TrFE) particles in the disordered convolution region (DCR) revealed recrystallization, representing the polymer chain structure and particle polarity. In comparison to nonrecrystallized nanoparticles, rPGd NPs@RGD exhibited remarkable stability and biocompatibility. Under ultrasound excitation, they generated significantly higher levels of reactive oxygen species, effectively inhibiting tumor cell proliferation, invasion, and migration. rPGd NPs@RGD demonstrated excellent MRI imaging capabilities and antitumor activity in U87 tumor-bearing mice. This study highlights the remarkable SPDT abilities of the developed nanoparticles, attributed to the microscopic morphological changes in the DCR that increase the nanoparticle's polarity and thus boost its potential for SPDT. This research opens new possibilities for utilizing P(VDF-TrFE) materials in advanced biomedical applications.

Exploring the antimicrobial potential of isoniazid loaded Cu-based metal-organic frameworks as a novel strategy for effective killing of Mycobacterium tuberculosis

Tuberculosis (TB) remains one of the most infectious pathogens with the highest human mortality and morbidity. Biofilm formation during Mycobacterium tuberculosis (Mtb) infection is responsible for bacterial growth, communication, and, most essentially, increased resistance/tolerance to antibiotics leading to higher bacterial persistence. Thus, biofilm growth is presently considered a key virulence factor in the case of chronic disease. Metal-Organic Frameworks (MOFs) have recently emerged as a highly efficient system to improve existing antibiotics' therapeutic efficacy and reduce adverse effects. In this regard, we have synthesized Cu-MOF (IITI-3) using a solvothermal approach. IITI-3 was well characterized by various spectroscopic techniques. Herein, IITI-3 was first encapsulated with isoniazid (INH) to form INH@IITI-3 with 10 wt% loading within 1 hour. INH@IITI-3 was well characterized by PXRD, TGA, FTIR, and BET surface area analysis. Furthermore, the drug release kinetics studies of INH@IITI-3 have been performed at pH 5.8 and 7.4 to mimic the small intestine and blood pH, respectively. The results show that drug release follows first-order kinetics. Furthermore, the antimycobacterial activity of INH@IITI-3 demonstrated significant bacterial killing and altered the structural morphology of the bacteria. Moreover, INH@IITI-3 was able to inhibit the mycobacterial biofilm formation upon treatment and showed less cytotoxicity toward the murine RAW264.7 macrophages. Thus, this work significantly opens up new possibilities for the applications of INH@IITI-3 in biofilm infections in Mtb and further contributes to TB therapeutics.

Rational design of copper(I)-doped metal-organic frameworks as dual-functional nanocarriers for combined chemo-chemodynamic therapy

Combination therapies are an increasingly important part of the antitumor medicine armamentarium. However, developing desirable nanomaterials for combination therapies is still a great challenge. Herein, a biocompatible Cu(I)-doped metal-organic framework (MOF) (denoted as CuZn-ZIF) is designed as a novel dual-functional nanocarrier. Doxorubicin molecules are covalently bound to the surface of the CuZn-ZIF and released by the cleavage of chemical bonds in an acidic environment, demonstrating the capacity of controlled drug release. More importantly, CuZn-ZIF nanocarriers can simultaneously play the role of nanocatalysts, capable of catalyzing H2O2 into a highly reactive intracellular toxic hydroxyl radical (˙OH). An in vivo study reveals that nanoparticles exhibit high antitumor efficacy through the combined performance of DOX and Cu(I), proving the great potential of this copper(I)-based MOF for combined chemo-chemotherapy to improve therapeutic efficacy.

Fabrication of a magnetic metal-organic framework/covalent organic framework composite for simultaneous magnetic solid-phase extraction of seventeen trace quinolones residues in meats

Effective capture of quinolones (QNs) in animal-derived food is a vital procedure for food safety monitoring. However, the lack of adsorption specificity and difficult to recycle in complex substrate conditions have been major problems for most of the adsorbents. In this work, a magnetic Fe3O4/MOF/COF composite (named Fe3O4@NH2-MIL-125@TpPa-SO3H) was successfully synthesized with good magnetic responsiveness and conspicuous affinity towards QNs. The Fe3O4/MOF/COF composite was used as a magnetic solid-phase extraction (MSPE) adsorbent for pretreatment and determination of QNs in meat samples. Under optimal MSPE conditions in combination with high performance liquid chromatography-quadrupole orbitrap high resolution mass spectrometer (HPLC-Q-Orbitrap HRMS), the proposed method had good linearity (R2 ≥ 0.9978) from 0.01 to 100ng g-1, low limits of detection (0.0016 to 0.0940ng g-1), good precision with relative standard deviations lower than 5.8%. This method was effectively applied to the detection of 17 QNs in the spiked pork, chicken and beef samples with satisfactory recoveries from 83.9 to 106.2%. The separation selectivity mainly due to the π-π interaction, hydrogen bonding, and electrostatic attraction between QNs and the sulfonic acid and amino functional groups of the composite. After verification, the stability and reusability of the composite meet the requirements of complex matrix sample pretreatment. The developed MSPE method based on the magnetic Fe3O4/MOF/COF composite provided an ideal sample pretreatment alternative for determining trace QNs in complex matrixes with selectivity, simplicity, rapidity, and efficiency.

Growth mechanisms and anisotropic softness-dependent conductivity of orientation-controllable metal-organic framework nanofilms

Conductive metal-organic frameworks (cMOFs) manifest great potential in modern electrical devices due to their porous nature and the ability to conduct charges in a regular network. cMOFs applied in electrical devices normally hybridize with other materials, especially a substrate. Therefore, the precise control of the interface between cMOF and a substrate is particularly crucial. However, the unexplored interface chemistry of cMOFs makes the controlled synthesis and advanced characterization of high-quality thin films, particularly challenging. Herein, we report the development of a simplified synthesis method to grow "face-on" and "edge-on" cMOF nanofilms on substrates, and the establishment of operando characterization methodology using atomic force microscopy and X-ray, thereby demonstrating the relationship between the soft structure of surface-mounted oriented networks and their characteristic conductive functions. As a result, crystallinity of cMOF nanofilms with a thickness down to a few nanometers is obtained, the possible growth mechanisms are proposed, and the interesting anisotropic softness-dependent conducting properties (over 2 orders of magnitude change) of the cMOF are also illustrated.

Alignment of Breathing Metal-Organic Framework Particles for Enhanced Water-Driven Actuation

As the majority of known metal-organic frameworks (MOFs) possess anisotropic crystal lattices and thus anisotropic physicochemical properties, a pressing practical challenge in MOF research is the establishment of robust and simple processing methods to fully harness the anisotropic properties of the MOFs in various applications. We address this challenge by applying an E-field to precisely align MIL-88A microcrystals and generate MIL-88A@polymer films. Thereafter, we demonstrate the impact of MOF crystal alignment on the actuation properties of the films as a proof of concept. We investigate how different anisotropies of the MIL-88A@polymer films, specifically, crystal anisotropy, particle alignment, and film composition, can lead to the synergetic enhancement of the film actuation upon water exposure. Moreover, we explore how the directionality in application of the external stimuli (dry/humid air stream, water/air interface) affects the direction and the extent of the MIL-88A@polymer film movement. Apart from the superior water-driven actuation properties of the developed films, we demonstrate by dynamometer measurements the higher degree of mechanical work performed by the aligned MIL-88A@polymer films with the preserved anisotropies compared to the unaligned films. The insights provided by this work into anisotropic properties displayed by aligned MIL-88A@polymer films promise to translate crystal performance benefits measured in laboratories into real-world applications. We anticipate that our work is a starting point to utilize the full potential of anisotropic properties of MOFs.