Responses of microRNA in digestive glands of mussel Mytilus galloprovincialis exposed to polystyrene nanoplastics.

Polystyrene nanoplastics (PS-NPs) are typical accumulated nanoplastics in the marine environment and organisms, and have strong potential risks to marine ecological environment and human health. MiRNAs could respond to and participate in the response process of environmental stressors. However, the response of miRNAs to nanoplastics has not been fully explored. In this study, miRNA responses of digestive glands in mussels Mytilus galloprovincialis treated by 200 nm PS-NPs (20, 200, 2000 µg/L) for 7 days were characterized by BGISEQ-500 deep sequencing and bioinformatics analysis, along with histopathological quantification with planimetric parameters on hematoxylin and eosin (H&E) staining. Results showed that one novel miRNA (novel_mir63) and seven known miRNAs (miR-34_2, miR-34_5, miR-281_8, let-7-5p_6, miR-10, miR-124, miR-29b-3p) were significantly (adjusted P-value < 0.05) differentially expressed after PS-NPs treatments, and most of them were down-regulated expect for novel_mir63 and miR-34_2. Function analysis of target genes corresponding to these differentially expressed miRNAs indicated that PS-NPs disturbed the process related to metabolism, aging, cardiac function, neural excitation, and repairment. Among them, acetyl-CoA C-acetyltransferase and purine metabolism pathway played vital connection roles. Meanwhile, significantly morphology changes of digestive tubes obtained from H&E stained sections also implied severely disrupted metabolic capability in digestive glands, reflected by significantly increased mean diverticular radius (MDR) and mean luminal radius (MLR) values and the ratio of MLR to mean epithelial thickness (MET), and significantly decreased MET value and MET/MDR. Overall, these findings have revealed new characterization of miRNAs and their target genes in mussel M. galloprovincialis under PS-NPs stress, and provide important clues to further elucidate the toxicity mechanisms of PS-NPs.

Patient-Specific Implants for Correction of Midfacial Aging.

The nasolabial folds (NLFs) may be shallowed with the use of nostril base augmentation. This study aimed to design and customize patient-specific implants (PSIs) with computer-aided design/computer-aided manufacturing (CAD/CAM) to correct NLF deepening caused by midfacial aging. The patient's head computed tomography data obtained and were used for reconstruction. The PSIs were customized by CAD/CAM techniques, which were implanted into a nasal base for shallow NLFs caused by midfacial aging. Preoperative and postoperative photos and a wrinkle severity rating scale were used to evaluate the changes in NLFs. Also, the global esthetic improvement scale was used to investigate the surgical satisfaction of patients. Eleven patients (22 NLFs) received PSIs in the nasal base (22 implants). The customized PSI matched well with premaxilla, reducing the difficulty of operation. After 3 to 12 months of follow-up, PSI was stable without foreign body reaction or inflammatory reaction. Postoperative wrinkle severity rating scale scores showed that NLF severity was reduced in all patients, with a significant esthetic improvement compared with preoperatively ( P < 0.01). The global esthetic improvement scale showed an extremely satisfied improved NLF in 27.27% of patients, much improved in 63.63%, and improved in 9.90% (2/22), and none reported change or poor NLF. Patient satisfaction with their midface appearance differed significantly before and after surgery ( P < 0.01). Individualized PSI designed with high precision and matching degree by CAD and prepared using CAM could be applied to overcome the limitations of noncustomized implants.

Receptor Ligand-Free Mesoporous Silica Nanoparticles: A Streamlined Strategy for Targeted Drug Delivery across the Blood-Brain Barrier.

Mesoporous silica nanoparticles (MSNs) represent a promising avenue for targeted brain tumor therapy. However, the blood-brain barrier (BBB) often presents a formidable obstacle to efficient drug delivery. This study introduces a ligand-free PEGylated MSN variant (RMSN25-PEG-TA) with a 25 nm size and a slight positive charge, which exhibits superior BBB penetration. Utilizing two-photon imaging, RMSN25-PEG-TA particles remained in circulation for over 24 h, indicating significant traversal beyond the cerebrovascular realm. Importantly, DOX@RMSN25-PEG-TA, our MSN loaded with doxorubicin (DOX), harnessed the enhanced permeability and retention (EPR) effect to achieve a 6-fold increase in brain accumulation compared to free DOX. In vivo evaluations confirmed the potent inhibition of orthotopic glioma growth by DOX@RMSN25-PEG-TA, extending survival rates in spontaneous brain tumor models by over 28% and offering an improved biosafety profile. Advanced LC-MS/MS investigations unveiled a distinctive protein corona surrounding RMSN25-PEG-TA, suggesting proteins such as apolipoprotein E and albumin could play pivotal roles in enabling its BBB penetration. Our results underscore the potential of ligand-free MSNs in treating brain tumors, which supports the development of future drug-nanoparticle design paradigms.

Critical Features for Mesoporous Silica Nanoparticles Encapsulated into Erythrocytes.

Mesoporous silica nanoparticles (MSNs) hold great potential as a versatile platform for biomedical applications, especially drug delivery. However, evidence shows that MSNs even when PEGylated are rapidly cleared from the bloodstream by the monocyte phagocytic system. Erythrocytes, also called red blood cells (RBCs), can serve as biocompatible carriers of various bioactive substances, including drugs, enzymes, and peptides. In this work, we synthesize a series of fluorescent PEGylated MSNs with different synthetic diameters ranging from 10 to 200 nm and investigate the size effect on their encapsulation in human RBCs (hRBCs) by a hypotonic dialysis-based method. According to fluorescence images and flow cytometry analyses, we demonstrated that a hydrodynamic diameter below 30 nm is critical for efficient MSN encapsulation. Confocal microscopy and scanning electron microscopy images further confirmed that PEGylated MSNs were successfully embedded inside RBC. PEGylation serves an important role not only for stabilizing MSNs in biological milieu but also for reducing significant hemolysis caused by bare MSNs and thus for successful encapsulation. In addition to PEGylation, we further introduce positively charged functional groups onto the MSNs to show that nanoparticle-encapsulated hRBCs could serve as depots for delivering biological molecules through electrostatic attraction or chemical conjugation with MSNs. Also, we verify the existence of CD47 membrane protein, a marker of self, on the nanoparticle-encapsulated hRBCs and assess its ability of circulation in the blood, which could act as a circulation reservoir for delivering pharmacological substances through an osmosis-based method with MSNs.

Internalization of mesoporous silica nanoparticles induces transient but not sufficient osteogenic signals in human mesenchymal stem cells.

The biocompatibility of nanoparticles is the prerequisite for their applications in biomedicine but can be misleading due to the absence of criteria for evaluating the safety and toxicity of those nanomaterials. Recent studies indicate that mesoporous silica nanoparticles (MSNs) can easily internalize into human mesenchymal stem cells (hMSCs) without apparent deleterious effects on cellular growth or differentiation, and hence are emerging as an ideal stem cell labeling agent. The objective of this study was to thoroughly investigate the effect of MSNs on osteogenesis induction and to examine their biocompatibility in hMSCs. Uptake of MSNs into hMSCs did not affect the cell viability, proliferation and regular osteogenic differentiation of the cells. However, the internalization of MSNs indeed induced actin polymerization and activated the small GTP-bound protein RhoA. The MSN-induced cellular protein responses as believed to cause osteogenesis of hMSCs did not result in promotion of regular osteogenic differentiation as analyzed by cytochemical stain and protein activity assay of alkaline phosphatase (ALP). When the effect of MSNs on ALP gene expression was further examined by reverse transcriptase polymerase chain reaction, MSN-treated hMSCs were shown to have significantly higher mRNA expression than control cells after 1-hour osteogenic induction. The induction of ALP gene expression by MSNs, however, was absent in cells after 1-day incubation with osteogenic differentiation. Together our results show that the internalization of MSNs had a significant effect on the transient protein response and osteogenic signal in hMSCs, thereby suggesting that the effects of nanoparticles on diverse aspects of cellular activities should be carefully evaluated even though the nanoparticles are generally considered as biocompatible at present.

Biosafety evaluations of well-dispersed mesoporous silica nanoparticles: towards in vivo-relevant conditions.

This study aimed to investigate how mesoporous silica nanoparticles (MSNs), especially focussing on their surface functional groups, interacted with Raw 264.7 macrophages, as well as with zebrafish embryos. Upon introducing nanoparticles into a biological milieu, adsorption of proteins and biomolecules onto the nanoparticle surface usually progresses rapidly. Nanoparticles bound with proteins can result in physiological and pathological changes, but the mechanisms remain to be elucidated. In order to evaluate how protein corona affected MSNs and the subsequent cellular immune responses, we experimented in both serum and serum-deprived conditions. Our findings indicated that the level of p-p38 was significantly elevated by the positively charged MSNs, whereas negatively charged MSNs resulted in marked ROS production. Most significantly, our experiments demonstrated that the presence of protein efficiently mitigated the potential nano-hazard. On the other hand, strongly positively charged MSNs caused 94% of the zebrafish embryos to die. In that case, the toxicity caused by the quaternary ammonium ligands on the surface of those nanoparticles was exerted in a dose-dependent manner. In summary, these fundamental studies here provide valuable insights into the design of better biocompatible nanomaterials in the future.

PEGylated silica nanoparticles encapsulating multiple magnetite nanocrystals for high-performance microscopic magnetic resonance angiography.

A novel magnetic resonance (MR) angiographic method, 3DΔR2-mMRA (three dimensional and ΔR2 based microscopy magnetic resonance angiography), is developed as a clinical diagnosis for depicting the function and structure of cerebral small vessels. However, the visibility of microvasculatures and the precision of cerebral blood volume calculation greatly rely on the transverse relaxivity and intravascular half-life of contrast agent, respectively. In this work, we report a blood pool contrast agent named H-Fe3O4@SiO2-PEG where multiple Fe3O4 nanocrystals are encapsulated in a thin silica shell to enhance the T2-relaxivity (r2 = 342.8 mM⁻¹ s⁻¹) and poly(ethylene glycol) (PEG) is employed to reduce opsonization and prolong circulation time of nanoparticles. Utilization of the newly developed H-Fe3O4@SiO2-PEG with a novel MR angiographic methodology, a high-resolution MR image of rat cerebral microvasculatures is successfully obtained.