Advances in plasmonic-based MOF composites, their bio-applications and perspectives in this field

Breakthrough in plasmonic enhanced MOFs: Design, synthesis, and catalytic mechanisms for various photocatalytic applications

Integrating metal-organic framework MOFs with plasmonic nanoparticles (NPs) addresses a significant shortcoming of standard plasmonic platforms: their low efficacy with non-adsorbing compounds. The corporation of porous MOFs complements the plasmonic characteristics, allowing for a broader range of applications. This study highlights recent advancements in the design, synthesis, structural engineering, and functional properties of heterostructures combining plasmonic NPs with MOFs, focusing on their plasmonic and catalytic reaction behaviors. These developments have greatly enhanced the protentional of plasmonic NPs-MOFs heterojunction in nanofabrication and various applications, such as chemical sensing techniques like localized surface plasmon resonance (LSPR) surface-enhanced Raman scattering (SERS) and surface-enhanced infrared absorbance (SEIRA). Additionally, the study thoroughly examines the interface interaction and photocatalytic performance of plasmonic NPs-MOFs. Various practical applications of plasmonic NPs-MOFs heterojunction are explored, including their promising role in tackling environmental challenges like industrial water pollution. Furthermore, we have a detailed discussion of various photocatalysis processes, including water splitting, CO2 reduction, pollutant degradation, and various sensing applications. Identifying current limitations and outlining future research directions to bridge existing knowledge gaps, including interface interaction, photocatalytic performance, and practical applications providing a comprehensive understanding, are the main aims of this review to inspire the development of next-generation plasmonic NPs-MOFs materials. It concludes by discussing future directions and challenges in composite development, emphasizing their potential to provide sustainable and efficient solutions for environmental remediation and energy conversion.

Advances in metal-organic framework-based drug delivery systems

Metal-organic frameworks (MOFs) are emerging crystalline porous materials with significant potential in biomedical applications, particularly as drug delivery systems (DDS). MOFs, composed of metal ions or clusters linked by organic ligands, feature large surface areas, adjustable pores, and diverse functionalities. This review comprehensively examines MOFs as advanced DDS, detailing their structures, synthesis, and drug loading mechanisms. We highlight high drug loading capacity and controlled release capabilities of MOF. Developments of design strategies for MOF-based DDS, namely, surface functionalization for targeted delivery and stimuli-responsive MOFs for controlled release, have been discussed and explored. The use of MOFs for delivering therapeutic agents such as small molecules, peptides, proteins, nucleic acids, and cancer drugs is discussed. Challenges addressed include stability, degradation in biological environments, potential toxicity, and scalability. Advances in hybrid MOF-based DDS, integrating MOFs with polymers, lipids, or nanoparticles for improved delivery, are also examined.

Highly Stable Flexible SERS-Imprinted Membrane Based on Plasmonic MOF Material for the Selective Detection of Chrysoidin in Environmental Water

Chrysoidin (CG) can be ingested into the human body through the skin and cause chronic toxicity, so the detection of CG levels in the environment is crucial. In this study, we synthesize F-Ag@ZIF-8/PVC molecular-imprinted membranes (FZAP-MIM) by an innovative combination of SERS detection, membrane separation, and a molecular-imprinted technique in order to perform the analysis of CG in water. The plasmonic MOF material as a SERS substrate helps to enrich the target and realize the spatial overlap of the target with the nanoparticle tip "hotspot". To avoid the poor reproducibility of Raman signals caused by the random arrangement of the powder substrate, polyvinyl chloride (PVC) is used to provide support and protection for the powder substrate. PVC has excellent dirt immunity and chemical stability, enabling the substrate to maintain Raman performance under complex and extreme detection conditions. FAZP-MIM has outstanding sensitivity and selectivity and can quickly and accurately capture targets even in the presence of similar structural interferences. The method showed superior recoveries in spiked recovery tests of real water samples and is expected to be practically applied to the trace detection of organic dye molecules in the environment.

MOF@platelet-rich plasma antimicrobial GelMA dressing: structural characterization, bio-compatibility, and effect on wound healing efficacy

In this study, a metal-organic framework (MOF) antimicrobial gel loaded with platelet-rich plasma (PRP) was prepared to improve the biological properties of gelatin gels and enhance their wound healing efficiency. PRP, MOF particles, and PRP-loaded MOF particles were each integrated into gelatin gels. The performance of the gels was evaluated for micro-structure, mechanical strength, in vitro bio-compatibility and pro-wound healing effects. The results revealed that the integration of PRP created a multi-cross-linked structure, increasing the ductility of the gels by over 40%. The addition of MOF particles significantly increased the strength of the gel from 13 kPa to 43 kPa. The combination of MOF and PRP further improved the cell induction and migration capabilities of the composite gel, and the scratches in the PRP/MOF@GelMA group had completely healed within 48 h. Due to the presence of MOF and PRP, the gel dressing exhibited inhibitory effects of 45.7% against Staphylococcus aureus (S. aureus) and 50.2% against Escherichia coli (E. coli). Different gels promoted tissue regeneration and wound healing ability of bacterial-infected wounds in C57 rats, while PRP/MOF@GelMA showed the strongest wound repair ability with 100% healing. This study provides a new strategy for the development and clinical application of gel dressings.

Nanocomposites Based on Magnetic Nanoparticles and Metal-Organic Frameworks for Therapy, Diagnosis, and Theragnostics

In the last two decades, metal-organic frameworks (MOFs) with highly tunable structure and porosity, have emerged as drug nanocarriers in the biomedical field. In particular, nanoscaled MOFs (nanoMOFs) have been widely investigated because of their potential biocompatibility, high drug loadings, and progressive release. To enhance their properties, MOFs have been combined with magnetic nanoparticles (MNPs) to form magnetic nanocomposites (MNP@MOF) with additional functionalities. Due to the magnetic properties of the MNPs, their presence in the nanosystems enables potential combinatorial magnetic targeted therapy and diagnosis. In this Review, we analyze the four main synthetic strategies currently employed for the fabrication of MNP@MOF nanocomposites, namely, mixing, in situ formation of MNPs in presynthesized MOF, in situ formation of MOFs in the presence of MNPs, and layer-by-layer methods. Additionally, we discuss the current progress in bioapplications, focusing on drug delivery systems (DDSs), magnetic resonance imaging (MRI), magnetic hyperthermia (MHT), and theragnostic systems. Overall, we provide a comprehensive overview of the recent advances in the development and bioapplications of MNP@MOF nanocomposites, highlighting their potential for future biomedical applications with a critical analysis of the challenges and limitations of these nanocomposites in terms of their synthesis, characterization, biocompatibility, and applicability.

Novel pH-Responsive CaO2@ZIF-67-HA-ADH Coating That Efficiently Enhances the Antimicrobial, Osteogenic, and Angiogenic Properties of Titanium Implants

Titanium-based implants often lead to premature implant failure due to the lack of antimicrobial, osteogenic, and angiogenic properties. To this end, a new strategy was developed to fabricate CaO2@ZIF-67-HA-ADH coating on titanium surfaces by combining calcium peroxide (CaO2) nanoparticles, zeolite imidazolate framework-67 (ZIF-67), and the chemical coupling hyaluronic acid-adipic acid dihydrazide (HA-ADH). We characterized CaO2@ZIF-67-HA-ADH with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results demonstrated that CaO2@ZIF-67-HA-ADH was pH-sensitive and decomposed rapidly under acidic conditions, and it released inclusions slowly under neutral conditions. Antibacterial experiments showed that the CaO2@ZIF-67-HA-ADH coating had excellent antibacterial properties and effectively killed methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PAO-1). Cell experiments revealed that the CaO2@ZIF-67-HA-ADH coating promoted pro-osteoblast adhesion, proliferation, and differentiation and also promoted the migration and angiogenesis of human umbilical vein endothelial cells (HUVECs), exhibiting excellent osteogenic and angiogenic properties. In in vivo animal implantation experiments, the CaO2@ZIF-67-HA-ADH coating exhibited strong antimicrobial activity early after implantation and excellent osseointegration later after implantation. In conclusion, the pH-responsive CaO2@ZIF-67-HA-ADH coating conferred excellent antibacterial, osteogenic, and angiogenic properties to titanium implants, which effectively enhanced osseointegration of the implants and prevented bacterial infection; the coating shows promise for use in the treatment of bone defects.