Nanoparticles traversing the extracellular matrix induce biophysical perturbation of fibronectin depicted by surface chemistry.

While the filtering and accumulation effects of the extracellular matrix (ECM) on nanoparticles (NPs) have been experimentally observed, the detailed interactions between NPs and specific biomolecules within the ECM remain poorly understood and pose challenges for in vivo molecular-level investigations. Herein, we adopt molecular dynamics simulations to elucidate the impacts of methyl-, hydroxy-, amine-, and carboxyl-modified gold NPs on the cell-binding domains of fibronectin (Fn), an indispensable component of the ECM for cell attachment and signaling. Simulation results show that NPs can specifically bind to distinct Fn domains, and the strength of these interactions depends on the physicochemical properties of NPs. NP-NH3+ exhibits the highest affinity to domains rich in acidic residues, leading to strong electrostatic interactions that induce severe deformation, potentially disrupting the normal functioning of Fn. NP-CH3 and NP-COO- selectively occupy the RGD/PHSRN motifs, which may hinder their recognition by integrins on the cell surface. Additionally, NPs can disrupt the dimerization of Fn through competing for residues at the dimer interface or by diminishing the shape complementarity between dimerized proteins. The mechanical stretching of Fn, crucial for ECM fibrillogenesis, is suppressed by NPs due to their local rigidifying effect. These results provide valuable molecular-level insights into the impacts of various NPs on the ECM, holding significant implications for advancing nanomedicine and nanosafety evaluation.

Silica nanoparticles inhibit cadmium uptake by the protozoan Tetrahymena thermophila without the need for adsorption.

The simultaneous presence of nanoparticles (NPs) and heavy metals in the environment may affect their mutual biological uptake. Although previous studies showed that NPs could alter the cellular uptake of heavy metals by their adsorption of heavy metals, whether they could affect metal uptake without the need for adsorption is unknown. This study examined the effects of silica (SiO2) NPs on the uptake of Cd ion by the protozoan Tetrahymena thermophila. We found that, even with negligible levels of adsorption, SiO2 NPs at concentrations of 3 to 100 mg/L inhibited Cd uptake. This inhibitory effect decreased as the ambient Cd concentration increased from 1 to 100 µg/L, suggesting the involvement of at least two transporters with different affinities for Cd. The transporters were subsequently identified by the specific protein inhibitors amiloride and tariquidar as NCX and ABCB1, which are responsible for the uptake of Cd at low and high Cd levels, respectively. RT-qPCR and molecular dynamics simulation further showed that the inhibitory effects of SiO2 NPs were attributable to the down-regulated expression of the genes Ncx and Abcb1, steric hindrance of Cd uptake by NCX and ABCB1, and the shrinkage of the central channel pore of the transporters in the presence of SiO2 NPs. SiO2 NPs more strongly inhibited Cd transport by NCX than by ABCB1, due to the higher binding affinity of SiO2 NPs with NCX. Overall, our study sheds new light on a previously overlooked influence of NPs on metal uptake and the responsible mechanism.

Benzylisoquinoline alkaloids with their antitumor activity from the aerial parts of Corydalis impatiens (pall.) Fisch.

Phytochemical investigation on the aerial parts of Corydalis impatiens (pall.) Fisch (Papaveraceae) resulted in the identification of four previous undescribed benzylisoquinoline alkaloids, impatienines A-D (1-4), together with 14 known analogues (5-18). The structures of these compounds were elucidated by extensive spectroscopic analysis (IR, HR-ESIMS, 1D- and 2D-NMR) as well as ECD calculations. All the compounds obtained were investigated for their inhibitory effect on the growth of A549, H1299 and HepG2 cancer cells. Compounds 7 and 15 exhibited pronounced inhibition against the A549 cancer cells with IC50 values of 6.81 µM and 3.17 µM, while the positive control cisplatin was 1.83 µM. Compounds 1-3 showed moderate inhibitory on the H1299 cancer cells. Compounds 4, 10-12, and 16 showed signiffcant activity against HepG2 cancer cells with IC50 values range of 4.41-8.75 µM.

Nitrogenous chemical constituents and their antitumor activities evaluation in vitro from the aerial parts of Corydalis impatiens (pall.) Fisch.

Four new compounds, impatienines E-H (1-4), together with 18 known ones (R)-N-methylcoclaurine (5), impatienine I (6), thalifoline (7), iseluxine (8), pisoquinoline (9), corydaldine (10), northalifoline (11), noroxyhydrastinine (12), 6,7-methylenedioxy-1(2H)-isoquinolinone (13), N-methylcorydaldine (14), oxyhydrastinine (15), corypalline (16), N-trans-feruloylmethoxytyramine (17), N-trans-feruloyldopamine (18), N-trans-feruloyltyramine (19), N-trans-sinapoyltyramine (20), N-cis-feruloyltyramine (21), N-cis-sinapoyltyramine (22) were obtained from the aerial parts of Corydalis impatiens (pall.) Fisch. Their structures were elucidated by extensive spectroscopic analysis (1D- and 2D-NMR, HR-ESIMS, IR, UV) and/or comparison with reported literature. The inhibitory effects of these isolates were also evaluated against the growth of cancer cells (A549, H1299 and HepG2). Compounds 2 and 4 showed significant inhibitory effect on HepG2 cancer cells with IC50 values of 8.62, 8.32 µM, respectively (positive control cisplatin: IC50, 6.32 µM). Compounds 22 and 4 exhibited moderate inhibitory effects against A549 cancer cells, and the IC50 values were 7.78 and 12.54 µM, respectively (positive control cisplatin: IC50, 1.83 µM).

Cistadesertosides B-E, Four New Diastereomeric Lignan Glycosides from the Stems of Cultural Cistanche deserticola in Tarim Desert.

Four previously undescribed diastereomeric lignan glycosides, namely cistadesertosides B-E (1-4) were isolated from the stems of cultural Cistanche deserticola in Tarim desert. The structures of these compounds were elucidated on the basis of extensive spectroscopic analyses, including IR, HR-ESI-MS, 1D and 2D NMR, circular dichroism (CD) data and chemical degradation. The in vitro anti-inflammatory activity of the isolates was also investigated. It showed that compounds 3 and 4 exhibited potential effects with IC50 values of 21.17 µM and 26.97 µM, respectively (positive control quercetin, IC50 , 10.01 µM).

Classification of diterpenoid alkaloids from Aconitum kusnezoffii Reichb. by liquid chromatography-tandem mass spectrometry-based on molecular networking.

Trace amounts of components in traditional Chinese medicine are considered pharmacological active substances used for treating many serious diseases. However, purifying all the trace substances and making clear their structures are not easy. In this context, high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry based molecular networking was applied to investigate the chemical constituents of the roots of Aconitum kusnezoffii Reichb., which led to the identification of 33 nodes in different groups (N1-N33). Based on the excremental fragmentation pathway of known diterpenoid alkaloids (1-9) and comparisons of characteristic ions and characteristic loss of analogs in literature, the structures of unknown ions were deduced. This work lays a foundation for the evaluation of the clinical basis and mechanism of traditional Chinese medicine from the aspects of chemistry. In this paper, the method speculation of unknown natural products by means of molecular network method is expected to be applied in the discovery and change law of relevant active components in clinical pharmacology and the change of complex systems caused by trace active compounds.

Cobalt(II)-Based Metal-Organic Framework as Bifunctional Materials for Ag(I) Detection and Proton Reduction Catalysis for Hydrogen Production.

A novel cobalt(II)-based metal-organic framework, Co-MB, was prepared by hydrothermal reaction of Co(NO3)2·6H2O, 3,3'-methylenediphthalic acid (H4mda), and 1,4-bis(imidazol-1-ylmethyl)-benzene in sodium hydroxide aqueous solution and structurally characterized. It shows a high stability in water within the pH range from 2.2 to 11.6, which could be used as a highly selective and sensitive luminescent sensor for Ag(I) detection in a luminescent enhancement manner, with LOD about 23 nM. Importantly, such stable Co-MB could also work as proton reduction catalyst for photodriven hydrogen production coupled with visible-light organic dyes as photosensitizer. The influence factors of hydrogen production including pH, TEA (triethylamine) contents, and kinds of organic dyes are studied in detail. Under optimal condition, the TON value was up to 5133 per cycle, and this Co-MB could also be reused at least 3 times.

A squaramide-based metal-organic framework as a luminescent sensor for the detection of lactose in aqueous solution and in milk.

A novel squaramide-containing metal-organic framework (MOF) has been designed and synthesized, which represents the first example of the luminescence selective detection of lactose over other monosaccharides and disaccharides. It was also used for the quantitative determination of lactose in milk.