Collagen Biocomposites Derived from Fish Waste: Doped and Cross-Linked with Functionalized Fe3O4 Nanoparticles and Their Comparative Studies with a Green Approach

Collagen-based nanobiocomposites can reabsorb and are biodegradable. These properties are effectively controlled by the number of cross-links. This study demonstrates an effortless and proficient approach for the functionalization of Fe₃O₄ NPs for cross-linking collagen obtained from biowaste, viz., fish scales of Lates Calcarifer, a marine origin. The size of Fe₃O₄ NPs (10-40 nm) was confirmed using particle size analysis. The physico-chemical properties of the aminosilane-coated Fe₃O₄ NPs cross-linked via succinylated collagen (FFCSC) were characterized using different analytical techniques and compared with succinylated collagen doped with Fe₃O₄ NPs (FDSC). Thermogravimetric analysis indicates cross-linked product FFCSC to be more stable than the FDSC. Also, the antibacterial effect was more pronounced for FFCSC than for FDSC nanobiocomposites. FFCSC exhibited improved mechanical properties which are essential for materials used for wound dressing purposes. Moreover, the cell viability of fibroblasts (3T3-L1) and their morphology studied by SEM and fluorescence microscopy showed biocompatibility of both FDSC and FFCSC. Thus, the current investigation, involves a waste to wealth approach where the collagen-based nanobiocomposites present an easy way to recycle the biowaste to value-added products using simple and clean methods, which are suitable for use in biomedical and environmental applications.

Fe-N Co-Doped Titanium Dioxide Nanoparticles Induce Cell Death in Human Lung Fibroblasts in a p53-Independent Manner

The advancement of nanotechnology in the last decade has developed an abundance of novel and intriguing TiO₂-based nanomaterials that are widely used in many sectors, including industry (as a food additive and colorant in cosmetics, paints, plastics, and toothpaste) and biomedicine (photoelectrochemical biosensing, implant coatings, drug delivery, and new emerging antimicrobial agents). Therefore, the increased use of engineered nanomaterials in the industry has raised serious concern about human exposure and their unexpected cytotoxic effects. Since inhalation is considered the most relevant way of absorbing nanomaterials, different cell death mechanisms induced in MRC-5 lung fibroblasts, following the exposure to functionalized TiO₂ NPs, were investigated. Long-term exposure to TiO₂ nanoparticles co-doped with 1% of iron and nitrogen led to the alteration of p53 protein activity and the gene expression controlled by this suppressor (NF-kB and mdm2), DNA damage, cell cycle disruptions at the G2/M and S phases, and lysosomal membrane permeabilization and the subsequent release of cathepsin B, triggering the intrinsic pathway of apoptosis in a Bax- and p53-independent manner. Our results are of major significance, contributing to the understanding of the mechanisms underlying the interaction of these nanoparticles with in vitro biological systems, and also providing useful information for the development of new photocatalytic nanoparticles that are active in the visible spectrum, but with increased biocompatibility.

Excretable, ultrasmall hexagonal NaGdF4:Yb50% nanoparticles for bimodal imaging and radiosensitization

BACKGROUND

In this study, we report on the synthesis, imaging, and radiosensitizing properties of ultrasmall β-NaGdF4:Yb50% nanoparticles as a multifunctional theranostic platform. The synthesized nanoparticles act as potent bimodal contrast agents with superior imaging properties compared to existing agents used for magnetic resonance imaging (MRI) and computed tomography (CT). Clonogenic assays demonstrated that these nanoparticles can act as effective radiosensitizers, provided that the nanoparticles are taken up intracellularly.

RESULTS

Our ultrasmall β-NaGdF4:Yb50% nanoparticles demonstrate improvement in T1-weighted contrast over the standard clinical MR imaging agent Gd-DTPA and similar CT signal enhancement capabilities as commercial agent iohexol. A 2 Gy dose of X-ray induced ~ 20% decrease in colony survival when C6 rat glial cells were incubated with non-targeted nanoparticles (NaGdF4:Yb50%), whereas the same X-ray dose resulted in a ~ 60% decrease in colony survival with targeted nanoparticles conjugated to folic acid (NaGdF4:Yb50%-FA). Intravenous administration of nanoparticles resulted in clearance through urine and feces within a short duration, based on the ex vivo analysis of Gd3+ ions via ICP-MS.

CONCLUSION

These biocompatible and in vivo clearable ultrasmall NaGdF4:Yb50% are promising candidates for further evaluation in image-guided radiotherapy applications.

Blocking Autophagic Flux Enhances Iron Oxide Nanoparticle Photothermal Therapeutic Efficiency in Cancer Treatment

Autophagy is a conservative eukaryotic pathway which plays a crucial role in maintaining cellular homeostasis, and dysfunction of autophagy is usually associated with pathological conditions. Recently, emerging reports have stressed that various types of nanomaterials and therapeutic approaches interfere with cellular autophagy process, which has brought up concerns to their future biomedical applications. Here, we present a study elaborating the relationships between autophagy and iron oxide nanoparticle (IONP)-mediated photothermal therapy in cancer treatment. Our results reveal that IONP photothermal effect could lead to autophagy induction in cancerous MCF-7 cells in a laser dose-dependent manner, and the inhibition of autophagy would enhance the photothermal cell killing by increasing cell apoptosis. In an MCF-7 xenograft model, cotreatment of autophagy inhibitor and IONP under laser exposure could promote the tumor inhibition rate from 43.26 to 68.56%, and the tumor immunohistochemistry assay of microtubule-associated protein 1-light chain 3 (LC3) and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling also demonstrate augmentation in both autophagosomes accumulation and apoptosis in vivo. This work helps us to better understand the regulation of autophagy during IONP-mediated photothermal therapy and provides us with a potential combination therapeutic approach of autophagy modulators and photothermal agents.

Journey to the Center of the Fetal Brain: Environmental Exposures and Autophagy

Fetal brain development is known to be affected by adverse environmental exposures during pregnancy, including infection, inflammation, hypoxia, alcohol, starvation, and toxins. These exposures are thought to alter autophagy activity in the fetal brain, leading to adverse perinatal outcomes, such as cognitive and sensorimotor deficits. This review introduces the physiologic autophagy pathways in the fetal brain. Next, methods to detect and monitor fetal brain autophagy activity are outlined. An additional discussion explores possible mechanisms by which environmental exposures during pregnancy alter fetal brain autophagy activity. In the final section, a correlation of fetal autophagy activity with the observed postnatal phenotype is attempted. Our main purpose is to provide the current understanding or a lack thereof mechanisms on autophagy, underlying the fetal brain injury exposed to environmental insults.

Overendocytosis of superparamagnetic iron oxide particles increases apoptosis and triggers autophagic cell death in human osteosarcoma cell under a spinning magnetic field

The toxicity of superparamagnetic iron oxide nanoparticles (SPIONs) is still a vital topic of debate and the mechanisms remain unclear. In the present study, overdose SPIONs could induce osteosarcoma cell death and the effects were exaggerated when combined with spinning magnetic field (SMF). In the combination group, mitochondrial transmembrane potential decrease more obviously and reactive oxygen species (ROS) was found to generate much higher in line with that of the apoptosis ratio. Meantime, amount of autophagy was induced. Inhibiting the autophagy generation by 3-methyladenine (3-MA) increase cell viability but decrease the caspase 3/7 and caspase 8 activities in combination groups, and inhibiting apoptosis took the same effect. In the end, the SPIONs effects on xenograft mice was examed by intratumoral injection. The result showed that the combination group could greatly decrease the tumor volume and prolong the lifespan of mice. In sum, the result indicated that overdose SPIONs induced ROS generation, and excessive ROS induced by combination of SPIONs and SMF contribute to autophagy formation, which play a apoptosis-promoting role that formed as a platform to recruits initiate the caspase activities.