Magnetosome-inspired synthesis of soft ferrimagnetic nanoparticles for magnetic tumor targeting.

Magnetic targeting is one of the most promising approaches for improving the targeting efficiency by which magnetic drug carriers are directed using external magnetic fields to reach their targets. As a natural magnetic nanoparticle (MNP) of biological origin, the magnetosome is a special "organelle" formed by biomineralization in magnetotactic bacteria (MTB) and is essential for MTB magnetic navigation to respond to geomagnetic fields. The magnetic targeting of magnetosomes, however, can be hindered by the aggregation and precipitation of magnetosomes in water and biological fluid environments due to the strong magnetic attraction between particles. In this study, we constructed a magnetosome-like nanoreactor by introducing MTB Mms6 protein into a reverse micelle system. MNPs synthesized by thermal decomposition exhibit the same crystal morphology and magnetism (high saturation magnetization and low coercivity) as natural magnetosomes but have a smaller particle size. The DSPE-mPEG-coated magnetosome-like MNPs exhibit good monodispersion, penetrating the lesion area of a tumor mouse model to achieve magnetic enrichment by an order of magnitude more than in the control groups, demonstrating great prospects for biomedical magnetic targeting applications.

Hierarchical-Bioinspired MOFs Enhanced Electromagnetic Wave Absorption.

Proteins exhibit complex and diverse multi-dimensional structures, along with a wide range of functional groups capable of binding metal ions. By harnessing the unique characteristics of proteins, it is possible to enhance the synthesis of metal-organic frameworks (MOFs) and modify their morphology. Here, the utilization of biomineralized bovine serum albumin (BSA) protein as a template for synthesizing Mil-100 with superior microwave absorption (MA) properties is investigated. The multi-dimensional structure and abundant functional groups of biomineralized BSA protein make it an ideal candidate for guiding the synthesis of Mil-100 with intricate network structures. The BSA@Mil-100 synthesized using this method exhibits exceptional uniformity and monodispersity of nanocrystals. The findings suggest that the BSA protein template significantly influences the regulation of nanocrystal and microstructure formation of Mil-100, resulting in a highly uniform and monodisperse structure. Notably, the synthesized 2-BSA@Mil-100 demonstrates a high reflection loss value of -58 dB at 8.85 GHz, along with a maximum effective absorption bandwidth value of 6.79 GHz, spanning from 6.01 to 12.8 GHz. Overall, this study highlights the potential of utilizing BSA protein as a template for MOF synthesis, offering an effective strategy for the design and development of high-performance MA materials.

Boosting SARS-CoV-2 Enrichment with Ultrasmall Immunomagnetic Beads Featuring Superior Magnetic Moment.

The isolation and enrichment efficiency of SARS-CoV-2 virus in complex biological environments is often relatively low, presenting challenges in direct detection and an increased risk of false negatives, particularly during the early stages of infection. To address this issue, we have developed a novel approach using ultrasmall magnetosome-like nanoparticles (≤10 nm) synthesized via biomimetic mineralization of the Mms6 protein derived from magnetotactic bacteria. These nanoparticles are surface-functionalized with hydrophilic carboxylated polyethylene glycol (mPEG2000-COOH) to enhance water solubility and monodispersity. Subsequently, they are coupled with antibodies targeting the receptor-binding domain (RBD) of the virus. The resulting magnetosome-like immunomagnetic beads (Mal-IMBs) exhibit high magnetic responsiveness comparable to commercial magnetic beads, with a saturation magnetization of 90.6 emu/g. Moreover, their smaller particle size provides a significant advantage by offering a higher specific surface area, allowing for a greater number of RBD single-chain fragment variable (RBD-scFv) antibodies to be coupled, thereby enhancing immune capture ability and efficiency. To validate the practicality of Mal-IMBs, we evaluated their performance in recognizing the RBD antigens, achieving a maximum capture ability of 83 µg/mg per unit mass. Furthermore, we demonstrated the binding capability of Mal-IMBs to SARS-CoV-2 pseudovirus using fluorescence microscopy. The Mal-IMBs effectively enriched the pseudovirus at a low copy concentration of 70 copies/mL. Overall, the small Mal-IMB exhibited excellent magnetic responsiveness and binding efficiency. By employing a multisite virus binding mechanism, it significantly improves the enrichment and separation of SARS-CoV-2 in complex environments, facilitating rapid detection of COVID-19 and contributing to effective measures against its spread.

A biomimetic camouflaged metal organic framework for enhanced siRNA delivery in the tumor environment.

Gene silencing through RNA interference (RNAi), particularly using small double-stranded RNA (siRNA), has been identified as a potent strategy for targeted cancer treatment. Yet, its application faces challenges such as nuclease degradation, inefficient cellular uptake, endosomal entrapment, off-target effects, and immune responses, which have hindered its effective delivery. In the past few years, these challenges have been addressed significantly by using camouflaged metal-organic framework (MOF) nanocarriers. These nanocarriers protect siRNA from degradation, enhance cellular uptake, and reduce unintended side effects by effectively targeting desired cells while evading immune detection. By combining the properties of biomimetic membranes and MOFs, these nanocarriers offer superior benefits such as extended circulation times, enhanced stability, and reduced immune responses. Moreover, through ligand-receptor interactions, biomimetic membrane-coated MOFs achieve homologous targeting, minimizing off-target adverse effects. The MOFs, acting as the core, efficiently encapsulate and protect siRNA molecules, while the biomimetic membrane-coated surface provides homologous targeting, further increasing the precision of siRNA delivery to cancer cells. In particular, the biomimetic membranes help to shield the MOFs from the immune system, avoiding unwanted immune responses and improving their biocompatibility. The combination of siRNA with innovative nanocarriers, such as camouflaged-MOFs, presents a significant advancement in cancer therapy. The ability to deliver siRNA with precision and effectiveness using these camouflaged nanocarriers holds great promise for achieving more personalized and efficient cancer treatments in the future. This review article discusses the significant progress made in the development of siRNA therapeutics for cancer, focusing on their effective delivery through novel nanocarriers, with a particular emphasis on the role of metal-organic frameworks (MOFs) as camouflaged nanocarriers.

Heat sensitive E-helix cut ferritin nanocages for facile and high-efficiency loading of doxorubicin.

Ferritin possesses a stable and uniform cage structure, along with tumor-targeting properties and excellent biocompatibility, making it a promising drug delivery vehicle. However, the current ferritin drug loading strategy involves complex steps and harsh reaction conditions, resulting in low yield and recovery of drug loading, which limits the clinical application prospects of ferritin nanomedicine. In this study, we utilized the high-efficiency heat-sensitivity of the multiple channel switch structures of the E-helix-cut ferritin mutant (Ecut-HFn) and Cu2+ assistance to achieve high-efficiency loading of chemotherapeutic drugs in a one-step process at low temperatures. This method features mild reaction conditions (45 °C), high loading efficiency (about 110 doxorubicin (Dox) per Ecut-HFn), and improved protein and Dox recovery rates (with protein recovery rate around 94 % and Dox recovery rate reaching up to 45 %). The prepared ferritin-Dox particles (Ecut-HFn-Cu-Dox) exhibit a uniform size distribution, good stability, and retain the natural tumor targeting ability of ferritin. Overall, this temperature-controlled drug loading strategy utilizing heat-sensitivity ferritin mutants is energy-saving, environmentally friendly, efficient, and easy to operate, offering a new perspective for scaling up the industrial production of ferritin drug carriers.

In Situ One-Pot Synthesis of Fe2O3@BSA Core-Shell Nanoparticles as Enhanced T1-Weighted Magnetic Resonance Imagine Contrast Agents.

Ultra-small-sized iron oxide nanoparticles with good biocompatibility are regarded as promising alternatives for the gadolinium-based contrast agents, which are widely used as a positive contrast agent in magnetic resonance imaging (MRI). However, the current preparation of the iron oxide magnetic nanoparticles with small sizes usually involves organic solvents, increasing the complexity of hydrophilic ligand replacement and reducing the synthesis efficiency. It remains a great challenge to explore new iron oxide nanoparticles with good biocompatibility and a high T1 contrast effect. Here, we reported a cage-like protein architecture self-assembled by approximately 6-7 BSA (bovine serum albumin) subunits. The BSA nanocage was then used as a biotemplate to synthesize uniformed and monodispersed Fe2O3@BSA nanoparticles with ultra-small sizes (∼3.5 nm). The Fe2O3@BSA nanoparticle showed a high r1 value of 6.8 mM-1 s-1 and a low r2/r1 ratio of 10.6 at a 3 T magnetic field. Compared to Gd-DTPA, the brighter signal and prolonged angiographic effect of Fe2O3@BSA nanoparticles could greatly benefit steady-state and high-resolution imaging. The further in vivo and in vitro assessments of stability, toxicity, and renal clearance indicated a substantial potential as a T1 contrast agent in preclinical MRI.

High-Temperature Wettability and Interactions between Y-Containing Ni-Based Alloys and Various Oxide Ceramics.

To obtain appropriate crucible materials for vacuum induction melting of MCrAlY alloys, four different oxide ceramics, including MgO, Y2O3, Al2O3, and ZrO2, with various microstructures were designed and characterized. The high-temperature wettability and interactions between Ni-20Co-20Cr-10Al-1.5Y alloys and oxide ceramics were studied by sessile drop experiments under vacuum. The results showed that all the systems exhibited non-wetting behavior. The contact angles were stable during the melting process of alloys and the equilibrium contact angles were 140° (MgO), 148° (Y2O3), 154° (Al2O3), and 157° (ZrO2), respectively. The interfacial reaction between the ceramic substrates and alloys occurred at high temperature. Though the ceramics had different microstructures, similar continuous Y2O3 reaction layer with thicknesses of about 25 μm at the alloy-ceramic interface in MgO, Al2O3, and ZrO2 systems formed. The average area percentage of oxides in the alloy matrices were 0.59% (MgO), 0.11% (Al2O3), 0.09% (ZrO2), and 0.02% (Y2O3), respectively. The alloys, after reacting with MgO ceramic, had the highest inclusion content, while those with the lowest content were in the Y2O3 system. Y2O3 ceramic was the most beneficial for vacuum induction melting of high-purity Y-containing Ni-based alloys.