A magnetic-dependent protein corona of tailor-made superparamagnetic iron oxides alters their biological behaviors

Integrating osteoimmunology and nanoparticle-based drug delivery systems for enhanced fracture healing

Fracture healing is a complex interplay of molecular and cellular mechanisms lasting from days to weeks. The inflammatory phase is the first stage of fracture healing and is critical in setting the stage for successful healing. There has been growing interest in exploring the role of the immune system and novel therapeutic strategies, such as nanoparticle drug delivery systems in enhancing fracture healing. Advancements in nanotechnology have revolutionized drug delivery systems to the extent that they can modulate immune response during fracture healing by leveraging unique physiochemical properties. Therefore, understanding the intricate interactions between nanoparticle-based drug delivery systems and the immune response, specifically macrophages, is essential for therapeutic efficacy. This review provides a comprehensive overview of the relationship between the immune system and nanoparticles during fracture healing. Specifically, we highlight the influence of nanoparticle characteristics, such as size, surface properties, and composition, on macrophage activation, polarization, and subsequent immune responses. IMPACT STATEMENT: This review provides valuable insights into the interplay between fracture healing, the immune system, and nanoparticle-based drug delivery systems. Understanding nanoparticle-macrophage interactions can advance the development of innovative therapeutic approaches to enhance fracture healing, improve patient outcomes, and pave the way for advancements in regenerative medicine.

Overexpressed transferrin receptor implied poor prognosis and relapse in gastrointestinal stromal tumors

Ferroptosis, as a novel-induced programmed cell death, plays critical roles in the pathogenesis of cancers. However, the promising biomarkers of ferroptosis in gastrointestinal stromal tumor (GIST) remain to be elucidated. Herein, the expression of ferroptosis-related genes was analyzed in GIST. Among the 64 ferroptosis-related genes, transferrin receptor (TFRC) expression presented a remarkable upregulation in high-risk patients through Gene Expression Omnibus (GEO) dataset analysis, as well as its significant change after imatinib was treated. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of TFRC-relevant genes revealed that TFRC expression was closely associated with cell growth pathways and metabolism-related pathways. Furthermore, patients at high risk of recurrence were more likely to exhibit high TFRC expression by immunohistochemistry. Additionally, high TFRC expression indicated an undesirable state of patient relapse, which could serve as a powerful significant independent predictor of recurrence-free survival (RFS). In summary, we systematically summarize the expression characteristics and clinical relevance of TFRC and show that TFRC can be used as a prognostic factor, which can be considered a potential therapeutic target in GIST.

Magnetic chitosan hydrogel induces neuronal differentiation of neural stem cells by activating RAS-dependent signal cascade

Our aim was to modulate magnetic cues to influence the differentiation of neural stem cell (NSC) into neuron during nerve repair and to explore corresponding mechanisms. Here, a magnetic hydrogel composed of chitosan matrices and magnetic nanoparticles (MNPs) with different content was prepared as the magnetic-stimulation platform to apply intrinsically-present magnetic cue and externally-applied magnetic field to NSC grown on the hydrogel. The MNP content had regulatory effects on neuronal differentiation and the MNPs-50 samples exhibited the best neuronal potential and appropriate biocompatibility in vitro, as well as accelerated the subsequent neuronal regeneration in vivo. Remarkably, the use of proteomics analysis parsed the underlying mechanism of magnetic cue-mediated neuronal differentiation form the perspective of protein corona and intracellular signal transduction. The intrinsically-present magnetic cues in hydrogel contributed to the activation of intracellular RAS-dependent signal cascades, thus facilitating neuronal differentiation. Magnetic cue-dependent changes in NSCs benefited from the upregulation of adsorbed proteins related to "neuronal differentiation", "cell-cell interaction", "receptor", "protein activation cascade", and "protein kinase activity" in the protein corona. Additionally, magnetic hydrogel acted cooperatively with the exterior magnetic field, showing further improving neurogenesis. The findings clarified the mechanism for magnetic cue-mediated neuronal differentiation, coupling protein corona and intracellular signal transduction.

Comparing the Colloidal Stabilities of Commercial and Biogenic Iron Oxide Nanoparticles That Have Potential In Vitro/In Vivo Applications

For the potential in vitro/in vivo applications of magnetic iron oxide nanoparticles, their stability in different physiological fluids has to be ensured. This important prerequisite includes the preservation of the particles' stability during the envisaged application and, consequently, their invariance with respect to the transfer from storage conditions to cell culture media or even bodily fluids. Here, we investigate the colloidal stabilities of commercial nanoparticles with different coatings as a model system for biogenic iron oxide nanoparticles (magnetosomes) isolated from magnetotactic bacteria. We demonstrate that the stability can be evaluated and quantified by determining the intensity-weighted average of the particle sizes (Z-value) obtained from dynamic light scattering experiments as a simple quality criterion, which can also be used as an indicator for protein corona formation.

Chemical and Biophysical Signatures of the Protein Corona in Nanomedicine

An inconvenient hurdle in the practice of nanomedicine is the protein corona, a spontaneous collection of biomolecular species by nanoparticles in living systems. The protein corona is dynamic in composition and may entail improved water suspendability and compromised delivery and targeting to the nanoparticles. How much of this nonspecific protein ensemble is determined by the chemistry of the nanoparticle core and its surface functionalization, and how much of this entity is dictated by the biological environments that vary spatiotemporally in vivo? How do we "live with" and exploit the protein corona without significantly sacrificing the efficacy of nanomedicines in diagnosing and curing human diseases? This article discusses the chemical and biophysical signatures of the protein corona and ponders challenges ahead for the field of nanomedicine.

Magneto-fluorescent nanocomposites: experimental and theoretical linkage for the optimization of magnetic hyperthermia

Magneto-fluorescent nanocomposites have been recognized as an emerging class of materials displaying great potential for improved magnetic hyperthermia assisted by optical imaging. In this study, we have designed a series of hybrid composites that consist of zinc doped Zn_xFe_3-xO₄ ferrites functionalized by polyethylene-glycol (PEG8000) and an orange-emitting platinum complex [Pt(phen)Cl₂]. Experimental and theoretical studies on the optimization of their magnetically-mediated heating properties were conducted. PEG was assembled around particles' surface by two different approaches; in situ and post-PEGylation. PEGylation ensured the optimal distance between the magnetic core and Pt(ii)-complex to maintain significant luminescence in the composite. The successful inclusion of the complex to the organic matrix was confirmed by a variety of spectroscopic techniques. A theoretical model was developed, based on linear response theory, in order to examine the composites' power losses dependence on their properties. Within this model, inter-particle interactions were quantified by inserting a mean dipolar energy term in the estimation of Néel relaxation time, and consequently, the size and concentration that maximize power loss were derived (20 nm and 4 mg mL^-1). Moreover, a decrease in the anisotropy of nanoparticles resulted in an increase in specific loss power values. Theoretical estimations are validated by experimental data when heating aqueous dispersions of composites in 24 kA m^-1, 765 kHz AMF for various values of concentration and size. Magnetic hyperthermia results showed that the theory-predicted values of optimum concentration and size delivered the maximum-specific loss power which was found equal to 545 W g^-1. By the present approach, a quantitative link between the particles' dipolar interactions and their heating properties is established, while opening new perspectives to nanotheranostic applications.

Paramagnetic Functionalization of Biocompatible Scaffolds for Biomedical Applications: A Perspective

The burst of research papers focused on the tissue engineering and regeneration recorded in the last years is justified by the increased skills in the synthesis of nanostructures able to confer peculiar biological and mechanical features to the matrix where they are dispersed. Inorganic, organic and hybrid nanostructures are proposed in the literature depending on the characteristic that has to be tuned and on the effect that has to be induced. In the field of the inorganic nanoparticles used for decorating the bio-scaffolds, the most recent contributions about the paramagnetic and superparamagnetic nanoparticles use was evaluated in the present contribution. The intrinsic properties of the paramagnetic nanoparticles, the possibility to be triggered by the simple application of an external magnetic field, their biocompatibility and the easiness of the synthetic procedures for obtaining them proposed these nanostructures as ideal candidates for positively enhancing the tissue regeneration. Herein, we divided the discussion into two macro-topics: the use of magnetic nanoparticles in scaffolds used for hard tissue engineering for soft tissue regeneration.

Brave new world revisited: Focus on nanomedicine

Nanomedicine is at a crossroads: with relatively few success stories in terms of clinical translation despite more and more research on increasingly sophisticated nanomaterials, it is important to consider whether we are on the right track. Indeed, it is crucial that we address the fact that while considerable efforts are being made to overcome barriers to translation from the bench to the clinic, scientists are still struggling to decipher fundamental aspects of nanomaterial interactions with biological systems. We believe that a key to the successful adoption of nanomedicines in oncology and beyond lies in a deeper understanding of underlying biological processes and in decoding interactions between engineered nanomaterials and biological systems. Here we provide an overview of progress in nanomedicine during the past 5 years.

Design of Functional Magnetic Nanocomposites for Bioseparation

Magnetic materials have been widely used in bioseparation in recent years due to their good biocompatibility, magnetic properties, and high binding capacity. In this review, we provide a brief introduction on the preparation and bioseparation applications of magnetic materials including the synthesis and surface modification of magnetic nanoparticles as well as the preparation and applications of magnetic nanocomposites in the separation of proteins, peptides, cells, exosomes and blood. The current limitations and remaining challenges in the fabrication process of magnetic materials for bioseparation will be also detailed.

Exploiting the protein corona: coating of black phosphorus nanosheets enables macrophage polarization via calcium influx

Black phosphorus nanosheets (BPNSs) have substantially promoted biomedical nanotechnology due to their unique photothermal and chemotherapeutic properties. However, there is still a limited molecular understanding of the effects of bio-nano interfaces on BPNSs and the subsequent impacts on physiological systems. Here, it is shown that black phosphorus-corona complexes (BPCCs) could function as immune modulators to promote the polarization of macrophages. Mechanistically, BPCCs could interact with calmodulin to activate stromal interaction molecule 2 and facilitate Ca2+ influx in macrophages, which induced the activation of p38 and NF-κB and polarized M0 macrophages to the M1 phenotype. As a result, BPCC-activated macrophages show greater migration towards cancer cells, 1.3-1.9 times higher cellular cytotoxicity and effective phagocytosis of cancer cells. These findings offer insights into the development of potential and unique applications of corona on BPNSs in nanomedicine.

Evaluation of orange peel-derived activated carbons for treatment of dye-contaminated wastewater tailings

Dyes are colored compounds which are visible even at trace concentrations. Due to their recalcitrance and esthetic persistence, certain methods are unable to effectively eliminate them. So far, adsorptive treatment using activated carbons (ACs) is one of the most successful methods. In this study, we have employed orange peel (OP) as a cost-effective alternative to the expensive coal- and coir-based precursors to synthesize ACs for cationic methylene blue (MB) and anionic methyl orange (MO) dye adsorption. The pre-carbonized OP was activated via H₂SO₄, NaOH, KOH, ZnCl₂, and H₃PO₄ to study the effects of activation reagents on dye removal efficiencies and mechanisms. Among several isotherm models employed to fit the adsorption data, the Langmuir and Sips models sufficiently estimated the maximum equilibrium uptakes close to the experimental values of 1012.10 ± 29.13, 339.82 ± 6.98, and 382.15 ± 8.62 mg/g, for ZnCl₂-AC (MO), ZnCl₂-AC (MB), and KOH-AC (MB), respectively. The adsorption mechanisms were suggested to involve electrostatic binding, pi-pi interactions, hydrogen bonding, and electron donor-acceptor reactions. Consequently, more than 99% removal efficiency was achieved from a laboratory organic wastewater sample bearing ~ 35 mg/L of MB. The results thus suggest that the synthesized ACs from agricultural waste have the tendencies to be applied to real dye wastewater treatment.

The Crown and the Scepter: Roles of the Protein Corona in Nanomedicine

Engineering nanomaterials are increasingly considered promising and powerful biomedical tools or devices for imaging, drug delivery, and cancer therapies, but few nanomaterials have been tested in clinical trials. This wide gap between bench discoveries and clinical application is mainly due to the limited understanding of the biological identity of nanomaterials. When they are exposed to the human body, nanoparticles inevitably interact with bodily fluids and thereby adsorb hundreds of biomolecules. A "biomolecular corona" forms on the surface of nanomaterials and confers a new biological identity for NPs, which determines the following biological events: cellular uptake, immune response, biodistribution, clearance, and toxicity. A deep and thorough understanding of the biological effects triggered by the protein corona in vivo will speed up their translation to the clinic. To date, nearly all studies have attempted to characterize the components of protein coronas depending on different physiochemical properties of NPs. Herein, recent advances are reviewed in order to better understand the impact of the biological effects of the nanoparticle-corona on nanomedicine applications. The recent development of the impact of protein corona formation on the pharmacokinetics of nanomedicines is also highlighted. Finally, the challenges and opportunities of nanomedicine toward future clinical applications are discussed.

Maghemite nanoparticles stabilize the protein corona formed with transferrin presenting different iron-saturation levels

Magnetic nanoparticles are ideal candidates for biomedical applications given their potential use in magnetic resonance imaging, magnetic hyperthermia and targeted drug delivery. Understanding protein-nanoparticle interactions in the blood stream is of major importance due to their potential risks, especially immunogenicity (i.e. the ability to induce an immune response). Here, we report on the interaction of superparamagnetic maghemite (γ-Fe2O3) nanoparticles with human blood plasma protein transferrin presenting different iron-saturation levels: partially iron-saturated (i.e. transferrin) and iron-free transferrin (i.e. apotransferrin). The nanoparticle-protein interaction and the protein corona formation were studied using biophysical and chemical approaches based on dynamic light scattering, gel electrophoresis, circular dichroism spectroscopy and differential scanning fluorimetry. We found that iron content governs the protein corona formation and induces a strong effect on the thermal stability of the bound protein. Our results demonstrate a stabilizing effect of the nanoparticles with a change of the unfolding position of approximately 10 °C towards higher temperatures for transferrin. Our study may be relevant for the further development of magnetic nanoparticles as diagnostic and therapeutic tools.

Protein corona of magnetic PEI/siRNA complex under the influence of a magnetic field improves transfection efficiency via complement and coagulation cascades

Magnetic fields enhance the silencing efficiency via the alteration of protein corona adsorbed on magnetic PEI/siRNA complex.

Protein Corona of Magnetic Hydroxyapatite Scaffold Improves Cell Proliferation via Activation of Mitogen-Activated Protein Kinase Signaling Pathway

The beneficial effect of magnetic scaffolds on the improvement of cell proliferation has been well documented. Nevertheless, the underlying mechanisms about the magnetic scaffolds stimulating cell proliferation remain largely unknown. Once the scaffold enters into the biological fluids, a protein corona forms and directly influences the biological function of scaffold. This study aimed at investigating the formation of protein coronas on hydroxyapatite (HA) and magnetic hydroxyapatite (MHA) scaffolds in vitro and in vivo, and consequently its effect on regulating cell proliferation. The results demonstrated that magnetic nanoparticles (MNP)-infiltrated HA scaffolds altered the composition of protein coronas and ultimately contributed to increased concentration of proteins related to calcium ions, G-protein coupled receptors (GPCRs), and MAPK/ERK cascades as compared with pristine HA scaffolds. Noticeably, the enriched functional proteins on MHA samples could efficiently activate of the MAPK/ERK signaling pathway, resulting in promoting MC3T3-E1 cell proliferation, as evidenced by the higher expression levels of the key proteins in the MAPK/ERK signaling pathway, including mitogen-activated protein kinase kinases1/2 (MEK1/2) and extracellular signal regulated kinase 1/2 (ERK1/2). Artificial down-regulation of MEK expression can significantly down-regulate the MAPK/ERK signaling and consequently suppress the cell proliferation on MHA samples. These findings not only provide a critical insight into the molecular mechanism underlying cellular proliferation on magnetic scaffolds, but also have important implications in the design of magnetic scaffolds for bone tissue engineering.

Dispersion of Nanoparticles in Different Media Importantly Determines the Composition of Their Protein Corona

Protein corona of nanoparticles (NPs), which forms when these particles come in to contact with protein-containing fluids, is considered as an overlooked factor in nanomedicine. Through numerous studies it has been becoming increasingly evident that it importantly dictates the interaction of NPs with their surroundings. Several factors that determine the compositions of NPs protein corona have been identified in recent years, but one has remained largely ignored-the composition of media used for dispersion of NPs. Here, we determined the effect of dispersion media on the composition of protein corona of polyacrylic acid-coated cobalt ferrite NPs (PAA NPs) and silica NPs. Our results confirmed some of the basic premises such as NPs type-dependent specificity of the protein corona. But more importantly, we demonstrated the effect of the dispersion media on the protein corona composition. The differences between constituents of the media used for dispersion of NPs, such as divalent ions and macromolecules were responsible for the differences in protein corona composition formed in the presence of fetal bovine serum (FBS). Our results suggest that the protein corona composition is a complex function of the constituents present in the media used for dispersion of NPs. Regardless of the dispersion media and FBS concentration, majority of proteins from either PAA NPs or silica NPs coronas were involved in the process of transport and hemostasis. Interestingly, corona of silica NPs contained three complement system related proteins: complement factor H, complement C3 and complement C4 while PAA NPs bound only one immune system related protein, α-2-glycoprotein. Importantly, relative abundance of complement C3 protein in corona of silica NPs was increased when NPs were dispersed in NaCl, which further implies the relevance of dispersion media used to prepare NPs.

Quantifying intra- and extracellular aggregation of iron oxide nanoparticles and its influence on specific absorption rate

A promising route to cancer treatment is hyperthermia, facilitated by superparamagnetic iron oxide nanoparticles (SPIONs). After exposure to an alternating external magnetic field, SPIONs generate heat, quantified by their specific absorption rate (SAR, in W g(-1) Fe). However, without surface functionalization, commercially available, high SAR SPIONs (EMG 308, Ferrotec, USA) aggregate in aqueous suspensions; this has been shown to reduce SAR. Further reduction in SAR has been observed for SPIONs in suspensions containing cells, but the origin of this further reduction has not been made clear. Here, we use image analysis methods to quantify the structures of SPION aggregates in the extra- and intracellular milieu of LNCaP cell suspensions. We couple image characterization with nanoparticle tracking analysis and SAR measurements of SPION aggregates in cell-free suspensions, to better quantify the influence of cellular uptake on SPION aggregates and ultimately its influence on SAR. We find that in both the intra- and extracellular milieu, SPION aggregates are well-described by a quasifractal model, with most aggregates having fractal dimensions in the 1.6-2.2 range. Intracellular aggregates are found to be significantly larger than extracellular aggregates and are commonly composed of more than 10(3) primary SPION particles (hence they are "superaggregates"). By using high salt concentrations to generate such superaggregates and measuring the SAR of suspensions, we confirm that it is the formation of superaggregates in the intracellular milieu that negatively impacts SAR, reducing it from above 200 W g(-1) Fe for aggregates composed of fewer than 50 primary particles to below 50 W g(-1) for superaggregates. While the underlying physical mechanism by which aggregation leads to reduction in SAR remains to be determined, the methods developed in this study provide insight into how cellular uptake influences the extent of SPION aggregation, and enable estimation of the reduction of SAR brought about via uptake induced aggregation.