Combinational Effects of Active Targeting, Shape, and Enhanced Permeability and Retention for Cancer Theranostic Nanocarriers

Combinatory modulation of the physical and biochemical characteristics of nanocarrier delivery systems is an emergent topic in the field of nanomedicine. Here, we studied the combined effects of incorporation of active targeting moieties into nanocarriers and their morphology affecting the enhanced permeation and retention effect for nanomedicine cancer therapy. Self-assembled lipid discoidal and vesicular nanoparticles with low-polydispersity sub-50 nm size range and identical chemical compositions were synthesized, characterized, and correlated with in vitro cancer cellular internalization, in vivo tumor accumulation and cancer treatments. The fact that folate-associated bicelle yields the best outcome is indicative of the preference for discoidal carriers over spherical carriers and the improved targeting efficacy due to the targeting ligand/receptor binding. The approach is successfully adopted to design the nanocarriers for photodynamic therapy, which yields a consistent trend in in vitro and in vivo efficacy: folate nanodiscs > folate vesicles > nonfolate nanodiscs > nonfolate vesicles. Folate discs not only have shown a higher tumor uptake and photothermal therapeutic efficiency, but also minimize skin photosensitivity side effects. The advantages of nanodiscoidal bicelles as nanocarriers, including well-defined size, robust formation, easy encapsulation of hydrophobic molecules (therapeutics and/or diagnostics), easy incorporation of targeting molecules, and low toxicity, enable the scalable manufacturing of a generalized in vivo multimodal delivery platform.

In vitro electrochemical corrosion and cell viability studies on nickel-free stainless steel orthopedic implants

The corrosion and cell viability behaviors of nanostructured, nickel-free stainless steel implants were studied and compared with AISI 316L. The electrochemical studies were conducted by potentiodynamic polarization and electrochemical impedance spectroscopic measurements in a simulated body fluid. Cytocompatibility was also evaluated by the adhesion behavior of adult human stem cells on the surface of the samples. According to the results, the electrochemical behavior is affected by a compromise among the specimen's structural characteristics, comprising composition, density, and grain size. The cell viability is interpreted by considering the results of the electrochemical impedance spectroscopic experiments.

Graphene-Based Biomaterials for Bone Regenerative Engineering: A Comprehensive Review of the Field and Considerations Regarding Biocompatibility and Biodegradation

Graphene and its derivatives have continued to garner worldwide interest due to their unique characteristics. Having expanded into biomedical applications, there have been efforts to employ their exceptional properties for the regeneration of different tissues, particularly bone. This article presents a comprehensive review on the usage of graphene-based materials for bone regenerative engineering. The graphene family of materials (GFMs) are used either alone or in combination with other biomaterials in the form of fillers in composites, coatings for both scaffolds and implants, or vehicles for the delivery of various signaling and therapeutic agents. The applications of the GFMs in each of these diverse areas are discussed and emphasis is placed on the characteristics of the GFMs that have implications in this regard. In tandem and of importance, this article evaluates the safety and biocompatibility of the GFMs and carefully elucidates how various factors influence the biocompatibility and biodegradability of this new class of nanomaterials. In conclusion, the challenges and opportunities regarding the use of the GFMs in regenerative engineering applications are discussed, and future perspectives for the developments in this field are proposed.

Aggregation-Enhanced Photoluminescence and Photoacoustics of Atomically Precise Gold Nanoclusters in Lipid Nanodiscs (NANO2)

The authors designed a structurally stable nano-in-nano (NANO2) system highly capable of bioimaging via an aggregation-enhanced NIR excited emission and photoacoustic response achieved based on atomically precise gold nanoclusters protected by linear thiolated ligands [Au25(SC n H2n+1)18, n = 4-16] encapsulated in discoidal phospholipid bicelles through a one-pot synthesis. The detailed morphological characterization of NANO2 is conducted using cryogenic transmission electron microscopy, small/wide angle X-ray scattering with the support of molecular dynamics simulations, providing information on the location of Au nanoclusters in NANO2. The photoluminescence observed for NANO2 is 20-60 times more intense than that of the free Au nanoclusters, with both excitation and emission wavelengths in the near-infrared range, and the photoacoustic signal is more than tripled. The authors attribute this newly discovered aggregation-enhanced photoluminescence and photoacoustic signals to the restriction of intramolecular motion of the clusters' ligands. With the advantages of biocompatibility and high cellular uptake, NANO2 is potentially applicable for both in vitro and in vivo imaging, as the authors demonstrate with NIR excited emission from in vitro A549 human lung and the KB human cervical cancer cells.

A universal discoidal nanoplatform for the intracellular delivery of PNAs

Peptide nucleic acids (PNAs) have gained considerable attention due to their remarkable potential in gene editing and targeting-based strategies. However, cellular delivery of PNAs remains a challenge in developing their broader therapeutic applications. Here, we investigated a novel complex made of lipid bicelles and PNA-based carriers for the efficient delivery of PNAs. For proof of concept, PNAs targeting microRNA (miR) 210 and 155 were tested. Comprehensive evaluation of positive as well as negative charge-containing bicelles with PNA : lipid ratios of 1 : 100, 1 : 1000, and 1 : 2500 was performed. The negatively charged bicelles with a PNA : lipid molar ratio of 1 : 2500 yielded a discoidal shape with a uniform diameter of ∼30 nm and a bilayer thickness of 5 nm, while the positively charged bicellar system contained irregular vesicles after the incorporation of PNA. Small-angle X-ray scattering (SAXS) analysis was performed to provide insight into how the hydrophobic PNAs interact with bicelles. Further, flow cytometry followed by confocal microscopy analyses substantiate the superior transfection efficiency of bicelles containing dye-conjugated antimiR PNAs. Functional analysis also confirmed miR inhibition by PNA oligomers delivered by bicelles. The nanodiscoidal complex opens a new pathway to deliver PNAs, which, on their own, are a great challenge to be endocytosed into cells.

Stable Discoidal Bicelles: A Platform of Lipid Nanocarriers for Cellular Delivery

Bicellar mixtures have been used as alignable membrane substrates for the structural characterization of membrane-associated proteins. Most recently, it has been shown that bicelles can serve as nanocarriers to effectively deliver hydrophobic molecules to cancer cells with a 3- to 10-fold enhancement compared to that of chemically identical liposomes. In this chapter, a detailed preparation protocol, common structural characterization methods, the structural stability and the cellular uptake of bicellar nanodisks are discussed.

Carbonyl reductase mRNA abundance and enzymatic activity as potential biomarkers of oxidative stress in marine fish

Carbonyl reductase (CBR) is an enzyme involved in protection from oxidative stress. In rainbow trout (Oncorhynchus mykiss), the hepatic mRNA abundance of the two isoforms (A and B) is increased after exposure to treated sewage effluents, as well as after exposure with β-naphthoflavone (β-NF) and the pro-oxidant paraquat. In this study, we show that the same chemicals similarly increase the single known hepatic CBR mRNA level and CBR catalytic activity in the coastal living eelpout (Zoarces viviparus). Hepatic CBR mRNA abundance and catalytic activity were also compared between eelpout collected at contaminated and reference sites on the Swedish west coast, but no differences were observed. In conclusion, CBR is a potential biomarker candidate for monitoring the exposure and effects of AhR agonists and/or pro-oxidants in the marine environment, but more research is needed to investigate temporal regulation as well as dose dependency for different chemicals. The mRNA and enzymatic assays presented in this study provide two additional tools for researchers interested in expanding their biomarker battery.

Changes Experienced by Low-Concentration Lipid Bicelles as a Function of Temperature

Differential scanning calorimetry (DSC) of dipalmitoyl phosphatidylcholine (DPPC), dihexanoyl phosphatidylcholine, and dipalmitoyl phosphatidylglycerol bicelles reveals two endothermic peaks. Based on analysis of small angle neutron scattering and small angle X-ray scattering data, the two DSC peaks are associated with the melting of DPPC and a change in bicellar morphology─namely, either bicelle-to-spherical vesicle or oblate-to-spherical vesicle. The reversibility of the two structural transformations was examined by DSC and found to be consistent with the corresponding small angle scattering data. However, the peak that is not associated with the melting of DPPC does not correspond to any structural transformation for bicelles containing distearoyl phosphatidylethanolamine conjugated with polyethylene glycol. Based on complementary experimental data, we conclude that membrane flexibility, lipid miscibility, and differential solubility between the long- and short-chain lipids in water are important parameters controlling the reversibility of morphologies experienced by the bicelles.

Trajectory of pulmonary congestion by lung ultrasound in patients with acute myocardial infarction and association with cardiac structure and function

Background

The PARADISE-MI trial examined the efficacy of sacubitril/valsartan in patients with acute myocardial infarction (AMI) complicated by reduced left ventricular ejection fraction (LVEF), pulmonary congestion or both. Little is known about the trajectory and echocardiographic correlates of pulmonary congestion in this population.

Purpose

We sought to assess the trajectory of pulmonary congestion using lung ultrasound (LUS) and its association with cardiac structure and function in a subset of patients enrolled in PARADISE- MI.

Methods

Participants underwent 8-zone LUS at baseline and 8 months. B-lines were quantified offline, blinded to treatment group, clinical findings, timepoint and outcomes by a core laboratory. Paired t-tests, chi-squared tests, and linear regression analyses were conducted.

Results

Among 152 patients (median age 65 years, 32% women, 35% obese, mean LVEF 41%), any B-lines were detectable in 87%, the median sum of B-lines in 8 zones was 4 [IQR 2–8], and 67% had ≥3 B-lines indicative of congestion. Greater number of B-lines at baseline was associated with larger left atrial (LA) size, higher E/e' and E/A ratios, greater degree of mitral regurgitation, worse right ventricular (RV) systolic function, and higher tricuspid regurgitation velocity (P trend <0.05 for all) (Figure 1). Among 115 patients with 8-month LUS data, there was a significant decline in number of B-lines from baseline (mean ± SD: −1.6±7.3; p=0.018). Adjusted for baseline, B-lines at follow-up were on average 6 (95% CI: 3, 9) higher in a patient who experienced an intercurrent heart failure (HF) event than a non-HF patient (p=0.001). Among 75 patients with ≥3 B-lines at baseline, a decrease in B-lines to <3, indicating decongestion, occurred in 37% and was similar in the sacubitril/valsartan and ramipril groups (36% vs. 39%, p=0.83).

Conclusions

In this post-AMI cohort, sonographic B-lines, indicating pulmonary congestion, were common at baseline and were significantly higher at follow-up in those who developed HF. Worse pulmonary congestion at baseline was associated with prognostically important echocardiographic markers of LV filling pressure, pulmonary pressure, and RV function.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Novartis