Zinc-Based Metal-Organic Frameworks in Drug Delivery, Cell Imaging, and Sensing

The design and structural frameworks for targeted drug delivery of medicinal compounds and improved cell imaging have been developed with several advantages. However, metal-organic frameworks (MOFs) are supplemented tremendously for medical uses with efficient efficacy. These MOFs are considered as an absolutely new class of porous materials, extensively used in drug delivery systems, cell imaging, and detecting the analytes, especially for cancer biomarkers, due to their excellent biocompatibility, easy functionalization, high storage capacity, and excellent biodegradability. While Zn-metal centers in MOFs have been found by enhanced efficient detection and improved drug delivery, these Zn-based MOFs have appeared to be safe as elucidated by different cytotoxicity assays for targeted drug delivery. On the other hand, the MOF-based heterogeneous catalyst is durable and can regenerate multiple times without losing activity. Therefore, as functional carriers for drug delivery, cell imaging, and chemosensory, MOFs' chemical composition and flexible porous structure allowed engineering to improve their medical formulation and functionality. This review summarizes the methodology for fabricating ultrasensitive and selective Zn-MOF-based sensors, as well as their application in early cancer diagnosis and therapy. This review also offers a systematic approach to understanding the development of MOFs as efficient drug carriers and provides new insights on their applications and limitations in utility with possible solutions.

Binding of chloroaurate to polytyrosine-PEG micelles leads to an anti-Turkevich pattern of reduction

Here we report formation of gold nanoparticles (GNPs) in micelles of polytyrosine-PEG copolymers that combine the properties of a reducer and a stabilizer. The size and properties of the GNPs were tailored by the excess chloroaurate over the copolymer. The latter quickly formed non-covalent complexes with HAuCl4 and then slowly reduced it to form GNPs. 3 Tyr residues are consumed by reduction of one mole of chloroaurate. The size of the GNPs was controlled by the [Tyr]/[Au(iii)] molar ratio. Small GNPs with D ≅ 8 nm were formed at [Tyr]/[Au(iii)] = 0.5-1.5. 90% of these small GNPs remained bound to the copolymer and could be stored in a lyophilized state. Such polypeptide-gold hybrid materials produced at [Tyr]/[Au(iii)] = 0.5 demonstrated high activity in the catalytic reduction of 4-nitrophenol by sodium borohydride. [Tyr]/[Au(iii)] = 5 led to the formation of large nanoplates (D ≅ 30-60 nm). Thus, in the polymer-based system the GNP size grew in line with the excess of the reducing agent in contrast to Turkevich synthesis of GNPs with citric acid, which also combines the functions of a stabilizer and a reducer. The difference results from the reduction of HAuCl4 in solution according to the Turkevich method and in the micelles of the amphiphilic polymer where the seed growth is limited by the amount of neighboring reducer.

Polyelectrolyte-coated ultra-small nanoparticles with Tb(III)-centered luminescence as cell labels with unusual charge effect on their cell internalization

The present work reports ultra-small polyelectrolyte-coated water insoluble Tb(III) complex species with bright Tb(III)-centered luminescence resulted from efficient ligand-to-metal energy transfer as efficient labels for Hep-2 cells. The flow cytometry data revealed the enhanced cellular uptake of negatively charged nanoparticles coated by the polystyrenesulfonate (PSS)-monolayer versus the positively charged nanoparticles. The latter are obtained by layer-by-layer deposition of polyethyleneimine (PEI) onto PSS-coated ones. Confocal and TEM images of Hep-2 cells exposed by the colloids confirm favorable cell internalization of the PSS- compared to PEI-PSS-coated colloids illustrating unusual charge-effect. Dynamic light scattering data indicate significant effect of the biological background exemplified by serum bovine albumin and phosphatidylcholine-based bilayers on the exterior charge and aggregation behavior of the colloids. The obtained results reveal the PSS-coated nanoparticles based on water insoluble Tb(III) complex as promising cell labels.

Ultra Small, mono dispersed green synthesized silver nanoparticles using aqueous extract of Sida cordifolia plant and investigation of antibacterial activity

The present study is focused on the synthesis of silver nano particles (Ag NPs) using an aqueous extract of the whole plant of Sida cordifolia as a potential bio-reducing agent and assessment of their antibacterial activity. UV-Vis spectroscopy of composed silver colloidal solution displayed surface Plasmon resonance peak at 420 nm. XRD and TEM analysis revealed the morphology as ultra-small, monodispersed spherical nanoparticles with face-centered cubic structure and mean particle size of 3-6 nm. This ultra-small nano size might owe to the slow reaction time and phytochemicals existing in the S. cordifolia extract. The Ag NPs are trailed for antibacterial activity against 5 fish (Aeromonas hydrophila, Pseudomonas fluorescence, Flavobacterium branchiophilum, Edwardsiella tarda and Yersinia rukeri) and 4 human (Escherichia coli, Klebsiella pneumonia, Bacillus subtilis and Staphyloccocus aureus) bacterial pathogens. In all the cases, Ag NPs from Sida cordifolia plant extract manifested noteworthy antibacterial effects on par with positive control i.e.; Gentamicin.

Novel Schiff base (DBDDP) selective detection of Fe (III): Dispersed in aqueous solution and encapsulated in silica cross-linked micellar nanoparticles in living cell

This work demonstrated the synthesis of (4E)-4-(4-(diphenylamino)benzylideneamino)-1,2-dihydro-1,5- dimethyl-2-phenylpyrazol-3-one (DBDDP) for Fe (III) detection in aqueous media and in the core of silica cross-linked micellar nanoparticles in living cells. The free DBDDP performed fluorescence enhancement due to Fe (III)-promoted hydrolysis in a mixed aqueous solution, while the DBDDP-doped silica cross-linked micellar nanoparticles (DBDDP-SCMNPs) performed an electron-transfer based fluorescence quenching of Fe (III) in living cells. The quenching fluorescence of DBDDP-SCMNPs and the concentration of Fe (III) exhibited a linear correlation, which was in accordance with the Stern-Volmer equation. Moreover, DBDDP-SCMNPs showed a low limit of detection (LOD) of 0.1 ppm and an excellent selectivity against other metal ions. Due to the good solubility and biocompatibility, DBDDP-SCMNPs could be applied as fluorescence quenching nanosensors in living cells.

Current progress in the controlled synthesis and biomedical applications of ultrasmall (<10 nm) NaREF4 nanoparticles

The design and fabrication of rare earth upconversion nanoparticle (UCNP)-based nanomedical platforms have evoked increasing interest. However, their bio-safety is always the most worrisome problem. Most nanoparticles can accumulate in the internal organs, leading to acute toxicity, a long-term inflammatory response, or even fibrosis and cancer. In contrast, ultrasmall (sub-10 nm) nanoparticles have minimal safety risk because they can escape from macrophages, pass biological barriers, and be easily degraded or excreted from the body. In this review, we mainly introduce new progress in preparation strategies, imaging and drug delivery with regards to ultrasmall UCNPs, with an emphasis on rare earth fluorides, NaREF₄. Finally, we discuss the future outlook and challenges relating to ultrasmall UCNPs.

Nanoscale hydrophilic colloids with high relaxivity and low cytotoxicity based on Gd(iii) complexes with Keplerate polyanions

Efficient hydrophilic stabilization of Gd(iii) complexes with Keplerate polyanions for high relaxivity, colloid stability and low cytotoxicity.

Lignin-assisted double acoustic irradiation for concentrated aqueous dispersions of carbon nanotubes

Carbon nanotube (CNTs) dispersion is one of the most challenging tasks for many applications. Lignin-assisted double sonication represents a low-cost and renewable alternative to prepare stable and concentrated suspensions of individualized CNTs.

Dispersion of Nanocrystalline Fe3O4 within Composite Electrodes: Insights on Battery-Related Electrochemistry

Aggregation of nanosized materials in composite lithium-ion-battery electrodes can be a significant factor influencing electrochemical behavior. In this study, aggregation was controlled in magnetite, Fe3O4, composite electrodes via oleic acid capping and subsequent dispersion in a carbon black matrix. A heat treatment process was effective in the removal of the oleic acid capping agent while preserving a high degree of Fe3O4 dispersion. Electrochemical testing showed that Fe3O4 dispersion is initially beneficial in delivering a higher functional capacity, in agreement with continuum model simulations. However, increased capacity fade upon extended cycling was observed for the dispersed Fe3O4 composites relative to the aggregated Fe3O4 composites. X-ray absorption spectroscopy measurements of electrodes post cycling indicated that the dispersed Fe3O4 electrodes are more oxidized in the discharged state, consistent with reduced reversibility compared with the aggregated sample. Higher charge-transfer resistance for the dispersed sample after cycling suggests increased surface-film formation on the dispersed, high-surface-area nanocrystalline Fe3O4 compared to the aggregated materials. This study provides insight into the specific effects of aggregation on electrochemistry through a multiscale view of mechanisms for magnetite composite electrodes.

Ultrasmall inorganic nanoparticles: State-of-the-art and perspectives for biomedical applications

Ultrasmall nanoparticulate materials with core sizes in the 1-3nm range bridge the gap between single molecules and classical, larger-sized nanomaterials, not only in terms of spatial dimension, but also as regards physicochemical and pharmacokinetic properties. Due to these unique properties, ultrasmall nanoparticles appear to be promising materials for nanomedicinal applications. This review overviews the different synthetic methods of inorganic ultrasmall nanoparticles as well as their properties, characterization, surface modification and toxicity. We moreover summarize the current state of knowledge regarding pharmacokinetics, biodistribution and targeting of nanoscale materials. Aside from addressing the issue of biomolecular corona formation and elaborating on the interactions of ultrasmall nanoparticles with individual cells, we discuss the potential diagnostic, therapeutic and theranostic applications of ultrasmall nanoparticles in the emerging field of nanomedicine in the final part of this review.

Delayed hepatic uptake of multi-phosphonic acid poly(ethylene glycol) coated iron oxide measured by real-time magnetic resonance imaging

We report on the synthesis, characterization, stability and pharmacokinetics of novel iron based contrast agents for magnetic resonance imaging (MRI).

A novel route towards well-dispersed short nanofibers and nanoparticles via electrospinning

A novel, simple, and widely applicable electrospinning–calcination–grinding route capable of preparing well-dispersed inorganic nanoparticles and short nanofibers is reported.

Catalytic performance of layered double hydroxide nanosheets toward phenol hydroxylation

CuMgAl-LDH@mSiO₂ nanosheets are prepared by delaminating the CuMgAl(NO₃)-LDH microcrystals followed by coating a porous layer of SiO₂, which show excellent catalytic performance toward phenol hydroxylation.

Ultrasmall [(64)Cu]Cu nanoclusters for targeting orthotopic lung tumors using accurate positron emission tomography imaging

Positron emission tomography (PET) imaging has received special attention owing to its higher sensitivity, temporal resolution, and unlimited tissue penetration. The development of tracers that target specific molecules is therefore essential for the development and utility of clinically relevant PET procedures. However, (64)Cu as a PET imaging agent generally has been introduced into biomaterials through macrocyclic chelators, which may lead to the misinterpretation of PET imaging results due to the detachment and transchelation of (64)Cu. In this study, we have developed ultrasmall chelator-free radioactive [(64)Cu]Cu nanoclusters using bovine serum albumin (BSA) as a scaffold for PET imaging in an orthotopic lung cancer model. We preconjugated the tumor target peptide luteinizing hormone releasing hormone (LHRH) to BSA molecules to prepare [(64)Cu]CuNC@BSA-LHRH. The prepared [(64)Cu]Cu nanoclusters showed high radiolabeling stability, ultrasmall size, and rapid deposition and diffusion into tumor, as well as predominantly renal clearance. [(64)Cu]CuNC@BSA-LHRH showed 4 times higher tumor uptake compared with that of [(64)Cu]CuNC@BSA by analyzing the (64)Cu radioactivity of tissues via gamma counting. The PET imaging using [(64)Cu]Cu nanoclusters as tracers showed more sensitive, accurate, and deep penetration imaging of orthotopic lung cancer in vivo compared with near-infrared fluorescence imaging. The nanoclusters provide biomedical research tools for PET molecular imaging.

Cellulose assisted combustion synthesis of porous Cu–Ni nanopowders

Cu–Ni nanoparticles were synthesized using cellulose assisted combustion synthesis method. The BET area, pore volume and pore size of these nanoparticles were higher than nanoparticles synthesized by solution combustion synthesis (SCS) method.

Dopamine derived copper nanocrystals used as an efficient sensing, catalysis and antibacterial agent

This study developed an innovative and effective method to synthesize highly luminescent dopamine-derived copper nanocrystals (CuNCs) with multifunctional properties.

Synthesis of ultra-small cysteine-capped gold nanoparticles by pH switching of the Au(I)-cysteine polymer

We report a synthetic approach for the production of ultra-small (0.6 nm) gold nanoparticles soluble in water with a precise control of the nanoparticle size. Our synthetic approach utilizes a pH-depending Au-cysteine polymer as a quencher for the AuNPs grown. The method extends the synthetic capabilities of nanoparticles with sizes down to 1 nm. In addition to the strict pH control, the existence of free -SH groups present in the mixture of reaction has been observed as a key requirement for the synthesis of small nanoparticles in mild conditions. UV-Vis, SAXS, XANES, EXAFS and HR-TEM, has been used to determinate the particle size, characterization of the gold precursor and gold-cysteine interaction.

Syntheses of cross-linked polymeric superparamagnetic beads with tunable properties

Novel, fast and reproducible way to obtain magnetic silica beads by PVA, silica and iron oxide nanoparticles cross-linking process.