Development of gelatin microsphere encapsulated Cu-based metal-organic framework nanohybrid for the methotrexate delivery

Effect of Microsphere Concentration on Catechin Release from Microneedle Arrays

In this work, microspheres were developed by cross-linking glutaraldehyde in an aqueous gelatin solution with a surfactant and solvent. A poly(vinyl alcohol) (PVA) solution was produced and combined with catechin-loaded microspheres. Different microsphere concentrations (0%, 5%, 10%, and 15%) were applied to the PVA microneedles. The moisture content, particle size, swelling, and drug release percentage of microneedles were studied using various microsphere concentrations. Fourier transform infrared and scanning electron microscopy (SEM) investigations validated the structure of gelatin microspheres as well as their decoration in microneedles. The SEM scans revealed that spherical microspheres with a wrinkled and folded morphology were created, with no physical holes visible on the surface. The gelatin microspheres generated had a mean particle size of 20-30 μm. Ex vivo release analysis indicated that microneedles containing 10% microspheres released the most catechin, with 42.9% at 12 h and 84.4% at 24 h.

Recent advances in metal-organic frameworks for stimuli-responsive drug delivery

After entering the human body, drugs for treating diseases, which are prone to delivery and release in an uncontrolled manner, are affected by various factors. Based on this, many researchers utilize various microenvironmental changes encountered during drug delivery to trigger drug release and have proposed stimuli-responsive drug delivery systems. In recent years, metal-organic frameworks (MOFs) have become promising stimuli-responsive agents to release the loaded therapeutic agents at the target site to achieve more precise drug delivery due to their high drug loading, excellent biocompatibility, and high stimuli-responsiveness. The MOF-based stimuli-responsive systems can respond to various stimuli under pathological conditions at the site of the lesion, releasing the loaded therapeutic agent in a controlled manner, and improving the accuracy and safety of drug delivery. Due to the changes in different physical and chemical factors in the pathological process of diseases, the construction of stimuli-responsive systems based on MOFs has become a new direction in drug delivery and controlled release. Based on the background of the rapidly increasing attention to MOFs applied in drug delivery, we aim to review various MOF-based stimuli-responsive drug delivery systems and their response mechanisms to various stimuli. In addition, the current challenges and future perspectives of MOF-based stimuli-responsive drug delivery systems are also discussed in this review.

Gelatin microsphere-alginate hydrogel combined system for sustained and gastric targeted delivery of 5-fluorouracil

In the current study, novel gelatin microspheres/methacrylated alginate hydrogel combined system (5-FU-GELms/Alg-MA) was developed for gastric targeted delivery of 5-fluorouracil as an anticancer agent. While water-in-oil emulsification method was used for the production of 5-FU-GELms, Alg-MA was synthesized through methacrylation reaction occurred by epoxide ring-opening mechanism. Then, 5-FU-GELms/Alg-MA hydrogel system was fabricated by the encapsulation of 5-FU-GELms into Alg-MA hydrogel network via UV-crosslinking. To evaluate applicability of fabricated 5-FU-GELms/Alg-MA as gastric targeted drug delivery vehicle, both swelling and in vitro drug release experiments were carried out at pH 1.2 medium resembling gastric fluid. Compared to drug release directly from 5-FU-GELms, 5-FU-GELms/Alg-MA hydrogel system showed more controlled and sustained drug release profile with lower amount of cumulative release starting from early stages, since hydrogel matrix created a barrier to the diffusion of 5-FU included in microspheres. Drug release kinetic results obtained by applying various kinetic models to release data showed that the mechanism of 5-FU release from 5-FU-GELms/Alg-MA hydrogel system is controlled by Fickian diffusion. All results revealed that 5-FU-GELms/Alg-MA hydrogel integrated system could be potentially utilized as gastric targeted drug carrier to enhance therapeutic efficacy and reduce systemic side effects in gastric cancer treatments for future studies.

Advances in surface-modified nanometal-organic frameworks for drug delivery

Nanometal-organic frameworks (NMOFs) are porous network structures composed of metal ions or metal clusters through self-assembly. NMOFs have been considered as a promising nano-drug delivery system due to their unique properties such as pore and flexible structures, large specific surface areas, surface modifiability, non-toxic and degradable properties. However, NMOFs face a series complex environment during in vivo delivery. Therefore, surface functionalization of NMOFs is vital to ensure that the structure of NMOFs remain stable during delivery, and can overcome physiological barriers to deliver drugs more accurately to specific sites, and achieve controllable release. In this review, the first part summarizes the physiological barriers that NMOFs faced during drug delivery after intravenous injection and oral administration. The second part summarizes the current main ways to load drugs into NMOFs, mainly including pore adsorption, surface attachment, formation of covalent/coordination bonds between drug molecules and NMOFs, and in situ encapsulation. The third part is the main review part of this paper, which summarizes the surface modification methods of NMOFs used in recent years to overcome the physiological barriers and achieve effective drug delivery and disease therapy, which are mainly divided into physical modifications and chemical modifications. Finally, the full text is summarized and prospected, with the hope to provide ideas for the future development of NMOFs as drug delivery.

Metal-Organic Frameworks Applications in Synergistic Cancer Photo-Immunotherapy

Conventional cancer therapies, such as radiotherapy and chemotherapy, can have long-term side effects. Phototherapy has significant potential as a non-invasive alternative treatment with excellent selectivity. Nevertheless, its applicability is restricted by the availability of effective photosensitizers and photothermal agents, and its low efficacy when it comes to avoiding metastasis and tumor recurrence. Immunotherapy can promote systemic antitumoral immune responses, acting against metastasis and recurrence; however, it lacks the selectivity displayed by phototherapy, sometimes leading to adverse immune events. The use of metal-organic frameworks (MOFs) in the biomedical field has grown significantly in recent years. Due to their distinct properties, including their porous structure, large surface area, and inherent photo-responsive properties, MOFs can be particularly useful in the fields of cancer phototherapy and immunotherapy. MOF nanoplatforms have successfully demonstrated their ability to address several drawbacks associated with cancer phototherapy and immunotherapy, enabling an effective and low-side-effect combinatorial synergistical treatment for cancer. In the coming years, new advancements in MOFs, particularly regarding the development of highly stable multi-function MOF nanocomposites, may revolutionize the field of oncology.

Gelatin as It Is: History and Modernity

The data concerning the synthesis and physicochemical characteristics of one of the practically important proteins-gelatin, as well as the possibilities of its practical application, are systematized and discussed. When considering the latter, emphasis is placed on the use of gelatin in those areas of science and technology that are associated with the specifics of the spatial/molecular structure of this high-molecular compound, namely, as a binder for the silver halide photographic process, immobilized matrix systems with a nano-level organization of an immobilized substance, matrices for creating pharmaceutical/dosage forms and protein-based nanosystems. It was concluded that the use of this protein is promising in the future.

Gelatin Matrix as Functional Biomaterial for Immobilization of Nanoparticles of Metal-Containing Compounds

The data concerning the synthesis and physicochemical characteristics of specific functional biomaterials-biopolymer-immobilized matrix systems based on gelatin as an array and chemical compounds, which include atoms of various metal elements-are systematized and discussed. The features of this biopolymer which determine the specific properties of the immobilized matrix systems formed by it and their reactivity, are noted. Data on gelatin-immobilized systems in which immobilized substances are elemental metals and coordination compounds formed as a result of redox processes, nucleophilic/electrophilic substitution reactions, and self-assembly (template synthesis), are presented. The possibilities of the practical use of metal-containing gelatin-immobilized systems are promising for the future; in particular, their potential in medicine and pharmacology as a vehicle for "targeted" drug delivery to various internal organs/tissues of the body, and, also, as potential biosensors is noted.

Fabrication of a Vitamin B12-Loaded Carbon Dot/Mixed-Ligand Metal Organic Framework Encapsulated within the Gelatin Microsphere for pH Sensing and In Vitro Wound Healing Assessment

Bacterial invasion is a serious concern during the wound healing process. The colonization of bacteria is mainly responsible for the pH fluctuation at the wound site. Therefore, the fabrication of a proper wound dressing material with antibacterial activity and pH monitoring ability is necessary to acquire a fast healing process. Therefore, this work is dedicated to designing a vitamin B12-loaded gelatin microsphere (MS) decorated with a carbon dot (CD) metal-organic framework (MOF) for simultaneous pH sensing and advanced wound closure application. The resultant MS portrayed a high specific surface area and a hierarchically porous structure. Furthermore, the surface of the resultant MS contained numerous carboxyl groups and amine groups whose deprotonation and protonation with the pH alternation are accountable for the pH-sensitive properties. The vitamin B12 release study was speedy from the MOF structure in an acidic medium, which was checked by gelatin coating, and a controlled drug release behavior was observed. The system showed excellent cytocompatibility toward the L929 cell line and remarkable antibacterial performance against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Furthermore, the combined effect of Zn²⁺, the imidazole unit, and CDs produces an outstanding bactericidal effect on the injury sites. Finally, the in vitro wound model suggests that the presence of the vitamin B12-loaded gelatin MS accelerates the proliferation of resident fibroblast L929 cells and causes tissue regeneration in a time-dependent manner. The relative wound area, % of wound closure, and wound healing speed values are remarkable and suggest the requirement for assessing the response of the system before exploiting its prospective in vivo application.

Recent Advances in Metal-Organic-Framework-Based Nanocarriers for Controllable Drug Delivery and Release

Metal-organic frameworks (MOFs) have a good designability, a well-defined pore, stimulus responsiveness, a high surface area, and a controllable morphology. Up to now, various MOFs have been widely used as nanocarriers and have attracted lots of attention in the field of drug delivery and release because of their good biocompatibility and high-drug-loading capacity. Herein, we provide a comprehensive summary of MOF-based nanocarriers for drug delivery and release over the last five years. Meanwhile, some representative examples are highlighted in detail according to four categories, including the University of Oslo MOFs, Fe-MOFs, cyclodextrin MOFs, and other MOFs. Moreover, the opportunities and challenges of MOF-based smart delivery vehicles are discussed. We hope that this review will be helpful for researchers to understand the recent developments and challenges of MOF-based drug-delivery systems.

D-mannose functionalized MgAl-LDH/Fe-MOF nanocomposite as a new intelligent nanoplatform for MTX and DOX co-drug delivery

Commonly the directly administered chemotherapy drugs lack targeting in tumor treatment. Thus, trying to improve cancer treatment efficiency led us to design a new intelligent system for cancer treatment. Considering these, in the current work, at first, the 2-aminoterephthalic acid (NH₂-BDC) intercalated layered double hydroxides (MgAl-(NH₂-BDC) LDH) were synthesized simply. Afterward, the in situ growth of the iron-based metal-organic frameworks in the presence of MgAl-(NH₂-BDC) LDH occurred (MgAl-LDH/Fe-MOF). In the end, the reaction of MgAl-LDH/Fe-MOF with D-mannose (D-Man) achieved the MgAl-LDH/Fe-MOF/D-Man ternary hybrid nanostructure. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis confirmed the formation of the monodisperse Fe-MOF with nanosize in the presence of MgAl-LDH. Importantly, methotrexate (MTX) and doxorubicin (DOX) entrapment efficiency reached respectively about 28 wt% and 21% for MgAl-LDH/Fe-MOF/D-Man. The in vitro drug release experiments revealed a higher drug release at pH 5.0 in comparison with pH 7.4 which revealed its promising potential for anticancer drug delivery applications. Bioassay results revealed that the co-drug-loaded MgAl-LDH/Fe-MOF/D-Man has higher cytotoxicity on MDA-MB 231 cells. At last, fluorescence microscopy and flow cytometric analysis confirmed the successful uptake of MgAl-LDH/Fe-MOF/D-Man into MDA-MB 231 cell lines, as well as its bioimaging potential. A survey in the published literature approved that this work is the first report on the evaluation of the MgAl-LDH/Fe-MOF/D-Man for targeted co-delivery of both MTX and DOX. Finally, results collectively demonstrate the importance of the biocompatible MgAl-LDH/Fe-MOF/D-Man as a hopeful candidate for biomedicinal applications from the targeted co-drug delivery and bioimaging potential viewpoints.

Metal-based nano-delivery platform for treating bone disease and regeneration

Owing to their excellent characteristics, such as large specific surface area, favorable biosafety, and versatile application, nanomaterials have attracted significant attention in biomedical applications. Among them, metal-based nanomaterials containing various metal elements exhibit significant bone tissue regeneration potential, unique antibacterial properties, and advanced drug delivery functions, thus becoming crucial development platforms for bone tissue engineering and drug therapy for orthopedic diseases. Herein, metal-based drug-loaded nanomaterial platforms are classified and introduced, and the achievable drug-loading methods are comprehensively generalized. Furthermore, their applications in bone tissue engineering, osteoarthritis, orthopedic implant infection, bone tumor, and joint lubrication are reviewed in detail. Finally, the merits and demerits of the current metal-based drug-loaded nanomaterial platforms are critically discussed, and the challenges faced to realize their future applications are summarized.

Investigation of light aromatics removal from industrial wastewater using nano metal organic framework

In this study, the adsorption of benzoic acid and phenols in the aqueous phase by MOF-Cu adsorbent was investigated. A high-performance liquid chromatography (HPLC) device was used to analyze the concentration of contaminants in the solution. Three isotherms, Freundlich, Langmuir, and Temkin were performed for adsorption of Benzoic Acid (BA) and Phenol contaminants. Correlation factor for adsorption isotherms were fitted into Langmuir aqueous BA and Phenol would be 99.89 and 99.98%, respectively. The equilibrium adsorption capacity MOF-Cu of BA and Phenol is 636.73 and 524.42 mg/g, respectively. In this study, high contaminant adsorption with π-π interaction and hydrogen bonding leads to the high capacity of MOFCu. In addition, the increase in adsorption capacity of benzoic acid is due to the electronegative property of oxygen in the carbonyl group and the similarity of the carboxylic acid functional group with the adsorbent. The result shows, that at initial time adsorption, has been a non-linear trend. In addition, the first-order kinetic model is not a suitable option for fitting the experimental data of adsorption kinetics and the adsorption kinetics of BA and Phenol is very well compatible with the semi-second order with the correlation Factor being 99.7 and 99.78, respectively. Also, the equilibrium adsorption capacity in pseudo-second order kinetic for BA and Phenol is 613.5 and 523.56 mg/g respectively.

Polymer-Based Hybrid Nanoarchitectures for Cancer Therapy Applications

Globally, cancer is affecting societies and is becoming an important cause of death. Chemotherapy can be highly effective, but it is associated with certain problems, such as undesired targeting and multidrug resistance. The other advanced therapies, such as gene therapy and peptide therapy, do not prove to be effective without a proper delivery medium. Polymer-based hybrid nanoarchitectures have enormous potential in drug delivery. The polymers used in these nanohybrids (NHs) provide them with their distinct properties and also enable the controlled release of the drugs. This review features the recent use of polymers in the preparation of different nanohybrids for cancer therapy published since 2015 in some reputed journals. The polymeric nanohybrids provide an advantage in drug delivery with the controlled and targeted delivery of a payload and the irradiation of cancer by chemotherapeutical and photodynamic therapy.

Copper-based metal-organic frameworks for biomedical applications

Metal-organic frameworks (MOFs) are a class of important porous, crystalline materials composed of metal ions (clusters) and organic ligands. Owing to the unique redox chemistry, photochemical and electrical property, and catalytic activity of Cu^2+/+, copper-based MOFs (Cu-MOFs) have been recently and extensively explored in various biomedical fields. In this review, we first make a brief introduction to the synthesis of Cu-MOFs and their composites, and highlight the recent synthetic strategies of two most studied representatives, three-dimensional HKUST-1 and two-dimensional Cu-TCPP. The recent advances of Cu-MOFs in the applications of cancer treatment, bacterial inhibition, biosensing, biocatalysis, and wound healing are summarized and discussed. Furthermore, we propose a prospect of the future development of Cu-MOFs in biomedical fields and beyond.

Two-dimensional nanomaterials for tumor microenvironment modulation and anticancer therapy

The development of two-dimensional (2D) nanomaterials for cancer therapy has attracted increasing attention due to their high specific surface area, unique ultrathin structure, electronic and photonic properties. For biomedical applications, investigations into the family of 2D materials have been sparked by graphene and its derivatives. Many 2D nanomaterials, including layered double hydroxides, transition metal dichalcogenides, nitrides and carbonitrides, black phosphorus nanosheets, and metal-organic framework nanosheets, are extensively explored as cancer theranostic platforms. In addition to the high drug loading, 2D nanomaterials are featured with improved physiological properties of drugs, prolonged blood circulation, and increased tumor accumulation and bioavailability. As a consequence, 2D nanomaterials have been widely examined in pre-clinical tumor therapy, particularly through the tumor microenvironment (TME) modulation. This review summarizes recent progresses in developing 2D nanomaterials for TME modulating-based cancer diagnosis and therapy. It is anticipated that this review will benefit researchers to obtain a deeper understanding of interactions between 2D nanomaterials and TME components and develop rational and reliable 2D nanomedicines for pre/clinical cancer theranostics.

Emerging 2D Nanomaterials for Biomedical Applications

Two-dimensional (2D) nanomaterials are an emerging class of biomaterials with remarkable potential for biomedical applications. The planar topography of these nanomaterials confers unique physical, chemical, electronic and optical properties, making them attractive candidates for therapeutic delivery, biosensing, bioimaging, regenerative medicine, and additive manufacturing strategies. The high surface-to-volume ratio of 2D nanomaterials promotes enhanced interactions with biomolecules and cells. A range of 2D nanomaterials, including transition metal dichalcogenides (TMDs), layered double hydroxides (LDHs), layered silicates (nanoclays), 2D metal carbides and nitrides (MXenes), metal-organic framework (MOFs), covalent organic frameworks (COFs) and polymer nanosheets have been investigated for their potential in biomedical applications. Here, we will critically evaluate recent advances of 2D nanomaterial strategies in biomedical engineering and discuss emerging approaches and current limitations associated with these nanomaterials. Due to their unique physical, chemical, and biological properties, this new class of nanomaterials has the potential to become a platform technology in regenerative medicine and other biomedical applications.

Application or function of citric acid in drug delivery platforms

Nontoxic materials with natural origin are promising materials in the designing and preparation of the new drug delivery systems (DDSs). Today's, citric acid (CA) has attracted a great deal of attention because of its special features; green nature, biocompatibility, low price, biodegradability, and commercially available property. So, CA has been employed in the preparation of the various platforms to induce a suitable property on their structure. Recently, several research groups investigated the CA-based platforms in different forms like tablets, dendrimers, hyperbranched polymers, (co)polymer, hydrogels, and nanoparticles as efficient DDSs. By considering an increasing amount of published articles in this field, for the first time, in this review, an overview of the published works regarding CA applications in the design of various DDSs is presented with a detailed and insightful discussion.

Nanoscale Metal-Organic Frameworks: Recent developments in synthesis, modifications and bioimaging applications

Porous Metal-Organic Frameworks (MOFs) have emerged as eye-catching materials in recent years. They are widely used in numerous fields of chemistry thanks to their desirable properties. MOFs have a key role in the development of bioimaging platforms that are hopefully expected to effectually pave the way for accurate and selective detection and diagnosis of abnormalities. Recently, many types of MOFs have been employed for detection of RNA, DNA, enzyme activity and small-biomolecules, as well as for magnetic resonance imaging (MRI) and computed tomography (CT), which are valuable methods for clinical analysis. The optimal performance of the MOF in the bio-imaging field depends on the core structure, synthesis method and modifications processes. In this review, we have attempted to present crucial parameters for designing and achieving an efficient MOF as bioimaging platforms, and provide a roadmap for researchers in this field. Moreover, the influence of modifications/fractionalizations on MOFs performance has been thoroughly discussed and challenging problems have been extensively addressed. Consideration is mainly focused on the principal concepts and applications that have been achieved to modify and synthesize advanced MOFs for future applications.

Carboxymethyl cellulose/tetracycline@UiO-66 nanocomposite hydrogel films as a potential antibacterial wound dressing

Designing an antibacterial agent with a suitable water vapor permeability, good mechanical properties, and controlled antibiotic release is a promising method for stopping bacterial infection in wound tissue. In this respect, this work aims to prepare novel flexible polymeric hydrogel films via integrating UiO-66 into the polymeric carboxymethyl cellulose (CMC) hydrogel for improving the mechanical and antibiotic release performances. First, we performed a green hydrothermal synthetic method to synthesis UiO-66 and followed by encapsulating Tetracycline (TC) through immersion in its aqueous solution. Also, the casting technique was utilized to integrate different concentrations of the TC-encapsulated UiO-66 (TC@UiO-66, 5% to 15%) in the polymeric CMC matrix (CMC/TC@UiO-66) cross-linked by citric acid and plasticized by glycerol. The release performance showed a low initial burst release with a controlled release over 72 h in the artificial sweat and simulated wound exudate (PBS, pH 7.4) media. The in vitro cytotoxicity and antibacterial activity results revealed a good cytocompatibility toward Human skin fibroblast (HFF-1) cells and a significant activity against both E. coli and S. aureus with 1.3 and 1.7 cm inhibition zone, respectively. The obtained results recommend CMC/TC@UiO-66 films as a potential antibacterial wound dressing.

Metal-organic framework IRMOFs coated with a temperature-sensitive gel delivering norcantharidin to treat liver cancer

BACKGROUND

Norcantharidin (NCTD) is suitable for the treatment of primary liver cancer, especially early and middle primary liver cancer. This compound can reduce tumors and improve immune function. However, the side effects of NCTD have limited its application. There is a marked need to reduce the side effects and increase the efficacy of NCTD.

AIM

To develop a nanomaterial carrier, NCTD-loaded metal-organic framework IRMOF-3 coated with a temperature-sensitive gel (NCTD-IRMOF-3-Gel), aiming to improve the anticancer activity of NCTD and reduce the drug dose.

METHODS

NCTD-IRMOF-3-Gel was obtained by a coordination reaction. The apparent characteristics and in vitro release of NCTD-IRMOF-3-Gel were investigated. Cell cytotoxicity assays, flow cytometry, and apoptosis experiments in mouse hepatoma (Hepa1-6) cells were used to determine the anti-liver cancer activity of NCTD-IRMOF-3-Gel in in vitro models.

RESULTS

The particle size of NCTD-IRMOF-3-Gel was 50-100 nm, and the particle size distribution was uniform. The release curve showed that NCTD-IRMOF-3-Gel had an obvious sustained-release effect. The cytotoxicity assays showed that the free drug NCTD and NCTD-IRMOF-3-Gel treatments markedly inhibited Hepa1-6 cell proliferation, and the inhibition rate increased with increasing drug concentration. By flow cytometry, NCTD-IRMOF-3-Gel was observed to block the Hepa1-6 cell cycle in the S and G2/M phases, and the thermosensitive gel nanoparticles may inhibit cell proliferation by inducing cell cycle arrest. Apoptosis experiments showed that NCTD-IRMOF-3-Gel induced the apoptosis of Hepa1-6 cells.

CONCLUSION

Our results indicated that the NCTD-IRMOF-3-Gel may be beneficial for liver cancer disease treatment.

Smart metal organic frameworks: focus on cancer treatment

Metal–organic frameworks (MOFs), as a prominent category of hybrid porous materials, have been broadly employed as controlled systems of drug delivery due to their inherent interesting properties.

Gold-like Thiolate-Protected Ultrasmall Cubic Copper Nanocluster-Based Metal-Organic Framework as a Selective Catalyst for Stepwise Synthesis of Unsymmetric Bistriazole by Click Reaction

We report a facile synthesis of a thiolate-protected water-soluble ultrasmall cubic copper nanocluster-based metal-organic framework (CuMOF) as an efficient and chemoselective catalyst for the azide-alkyne click reaction. Interestingly, the diffuse reflectance spectra of CuMOFs exhibit three discrete plasmon bands at 463, 505, and 674 nm, which are similar to those corresponding to the fingerprint region of thiolate-protected atomically precise Au₂₅ nanoclusters; hence, CuMOFs are termed as gold-like ultrasmall cubic copper nanoclusters. The high-resolution transmission electron microscopy (HRTEM) and powder X-ray diffraction (XRD) patterns confirm the cubic morphology of CuMOFs with nanoclusters showing particle size distribution of ∼2-12 nm. The matrix-assisted laser desorption ionization (MALDI) spectrum of CuMOFs is attributed to the individual particles consisting of few Cu_n(SR)_m with Cu(0) core atoms and Cu(I)SR staples, i.e., Cu₂(SR)₄, Cu(SR)₆, Cu₃(SR)₇, and Cu₄(SR)₈. To our surprise, the unsymmetric bistriazoles resulting from the click reaction of bifunctional azides and alkynes in the presence of CuMOFs were achieved by step-by-step conversion of the terminal azide selectively with maximum yield in the range of 70-88%. The nitrogen adsorption-desorption studies confirm the size-dependent surface area, pore volume, and pore size for the CuMOFs prepared by varying metal-to-ligand ratios. The plausible mechanism for the selective mono-click at CuMOFs suggests the existence of bifunctional terminal interactions via thiol and sulfonate groups that might have provided the site-isolation-based active sites for selective catalysis. The easy recovery of CuMOFs and their reusability up to 5 times without significant loss of activity are very promising for the selective organic conversions in pharmaceutical and industrial formulations.

Metal-organic frameworks for virus detection

Virus severely endangers human life and health, and the detection of viruses is essential for the prevention and treatment of associated diseases. Metal-organic framework (MOF), a novel hybrid porous material which is bridged by the metal clusters and organic linkers, has become a promising biosensor platform for virus detection due to its outstanding properties including high surface area, adjustable pore size, easy modification, etc. However, the MOF-based sensing platforms for virus detection are rarely summarized. This review systematically divided the detection platforms into nucleic acid and immunological (antigen and antibody) detection, and the underlying sensing mechanisms were interpreted. The nucleic acid sensing was discussed based on the properties of MOF (such as metal ion, functional group, geometry structure, size, porosity, stability, etc.), revealing the relationship between the sensing performance and properties of MOF. Moreover, antibodies sensing based on the fluorescence detection and antigens sensing based on molecular imprinting or electrochemical immunoassay were highlighted. Furthermore, the remaining challenges and future development of MOF for virus detection were further discussed and proposed. This review will provide valuable references for the construction of sophisticated sensing platform for the detection of viruses, especially the 2019 coronavirus.

Two-dimensional metal organic frameworks for biomedical applications

Two-dimensional (2D) metal organic frameworks (MOFs), are an emerging class of layered nanomaterials with well-defined structure and modular composition. The unique pore structure, high flexibility, tunability, and ability to introduce desired functionality within the structural framework, have led to potential use of MOFs in biomedical applications. This article critically reviews the application of 2D MOFs for therapeutic delivery, tissue engineering, bioimaging, and biosensing. Further, discussion on the challenges and strategies in next generation of 2D MOFs are also included. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Facile preparation of pH-sensitive chitosan microspheres for delivery of curcumin; characterization, drug release kinetics and evaluation of anticancer activity

Curcumin (CUR) is a lowly water-soluble natural polyphenol with chemopreventive and chemotherapeutic activities. Hence, to achieve the system with good CUR loading ability, porous MIL-88 (Fe) was prepared in the presence of the presynthesized graphene quantum dots (GQDs) (GQDs@MIL-88 (Fe)). In the following, CUR loaded in the fabricated GQDs@MIL-88 (Fe) nanohybrid. The characterization techniques; Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL), and Brunauer-Emmett-Teller (BET) analysis showed success in the synthesis of GQDs@MIL-88 (Fe). Moreover, the FT-IR analysis displayed the loading of CUR and the formation of CUR@GQDs@MIL-88(Fe). Chitosan (CS) was used as a green coating to enhance the biocompatibility of the prepared system (CS/CUR@GQDs@MIL-88(Fe). The fabricated microspheres showed pH-sensitive swelling behavior and released 38.3% of CUR in pH 5.0 which is better fitted with the First-order kinetic model (R² = 0.9726). In comparison with CUR@GQDs@MIL-88(Fe), the MTT and DAPI assay exhibited less toxic effect for CS/CUR@GQDs@MIL-88(Fe) against MDA-MB 231 cells. Moreover, the safety of the CS/CUR@GQDs@MIL-88(Fe) confirmed after incubation against MCF 10A as a model of the normal cell line. The results conveyed a new concept that the CS/CUR@GQDs@MIL-88(Fe) is a potential candidate for using as a biocompatible carrier with controlled drug delivery ability.

Fabrication of chitosan-polyethylene glycol nanocomposite films containing ZIF-8 nanoparticles for application as wound dressing materials

Biocompatible nanocomposite films based on chitosan (CS) and polyethylene glycol (PEG) polymers containing cephalexin (CFX) antibiotic drug and zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) were designed and fabricated to develop wound dressing materials capable of controlled drug release. Swelling experiment was performed in three acidic, neutral, and alkaline solutions. The tensile strength test reflected that upon increasing the NPs loading within the films, the tensile strength was enhanced but the elongation at break was diminished. The release of the CFX was intensively increased within approximately 3, 8, and 10 h (burst release) in acidic, neutral, and alkaline media, respectively while after that the CFX was smoothly released over time (sustained release). The antibacterial activities of all films were examined against Gram-positive (S. aureus, B. cereus) and Gram-negative (E. coli, P. aeruginosa, and Acinetobacter) bacteria frequently found in the infected wounds. Moreover, the MTT assay revealed that all films had high cell viabilities towards the L929 fibroblast cells confirming these nanocomposites could be used as favorable wound dressing materials. Finally, the film containing 4% ZIF-8 NPs (film 5) was chosen as the best sample due to it revealed appropriate mechanical properties, swelling, drug release and cell viability among all samples examined.

Smart co-delivery of 6-mercaptopurine and methotrexate using disulphide-based PEGylated-nanogels for effective treatment of breast cancer

Smart co-delivery of 6-mercaptopurine and methotrexate using disulphide-based PEGylated-nanogels.