The atrazine nanodelivery system, composed of poly(ε-caprolactone) (PCL+ATZ) nanocapsules (NCs), has demonstrated efficient delivery of the active ingredient to target plants in previous studies, leading to greater herbicide effectiveness than conventional formulations. Established nanosystems can be enhanced or modified to generate new biological activity patterns. Therefore, this study aimed to evaluate the effect of chitosan coating of PCL+ATZ NCs on herbicidal activity and interaction mechanisms with Bidens pilosa plants. Chitosan-coated NCs (PCL/CS+ATZ) were synthesized and characterized for size, zeta potential, polydispersity, and encapsulation efficiency. Herbicidal efficiency was assessed in postemergence greenhouse trials, comparing the effects of PCL/CS+ATZ NCs (coated), PCL+ATZ NCs (uncoated), and conventional atrazine (ATZ) on photosystem II (PSII) activity and weed control. Using a hydroponic system, we evaluated the root absorption and shoot translocation of fluorescently labeled NCs. PCL/CS+ATZ presented a positive zeta potential (25 mV), a size of 200 nm, and an efficiency of atrazine encapsulation higher than 90%. The postemergent herbicidal activity assay showed an efficiency gain of PSII activity inhibition of up to 58% compared to ATZ and PCL+ATZ at 96 h postapplication. The evaluation of weed control 14 days after application ratified the positive effect of chitosan coating on herbicidal activity, as the application of PCL/CS+ATZ at 1000 g of a.i. ha-1 resulted in better control than ATZ at 2000 g of a.i. ha-1 and PCL+ATZ at 1000 g of a.i. ha-1. In the hydroponic experiment, chitosan-coated NCs labeled with a fluorescent probe accumulated in the root cortex, with a small quantity reaching the vascular cylinder and leaves up to 72 h after exposure. This behavior resulted in lower leaf atrazine levels and PSII inhibition than ATZ. In summary, chitosan coating of nanoatrazine improved the herbicidal activity against B. pilosa plants when applied to the leaves but negatively affected the root-to-shoot translocation of the herbicide. This study opens avenues for further investigations to improve and modify established nanosystems, paving the way for developing novel biological activity patterns.

OBJECTIVE: This study investigated the associations of the surface charge of low-density lipoprotein (LDL) with the serum LDL-cholesterol and atherosclerosis levels in a community-based Japanese population.
METHODS: The study had a cross-sectional design and included 409 community residents aged 35-79 years who did not take medications for dyslipidemia. The potential electric charge of LDL and the zeta potential, which indicate the surface charge of LDL, were measured by laser Doppler microelectrophoresis. The correlations of the zeta potential of LDL (-mV) with the serum LDL-cholesterol levels (mg/dL), cardio-ankle vascular index (CAVI), and serum high-sensitivity C-reactive protein (hsCRP) levels (log-transformed values, mg/L) were examined using Pearson\'s correlation coefficient (r). Linear regression models were constructed to examine these associations after adjusting for potential confounding factors.
RESULTS: A total of 201 subjects with correctly stored samples were included in the primary analysis for zeta potential measurement. An inverse correlation was observed between the LDL zeta potential and the serum LDL-cholesterol levels (r=-0.20; p=0.004). This inverse association was observed after adjusting for sex, age, dietary cholesterol intake, smoking status, alcohol intake, body mass index, and the serum levels of the major classes of free fatty acids (standardized β=-6.94; p=0.005). However, the zeta potential of LDL showed almost no association with CAVI or the serum hsCRP levels. Similar patterns were observed in the 208 subjects with compromised samples as well as all the original 409 subjects.
CONCLUSIONS: A higher electronegative surface charge of LDL was associated with lower serum LDL-cholesterol levels in the general Japanese population.

The precise mechanisms underlying the cellular response to static electric cues remain unclear, limiting the design and development of biomaterials that utilize this parameter to enhance specific biological behaviours. To gather information on this matter we have explored the interaction of collagen type-I, the most abundant mammalian extracellular protein, with poly(vinylidene fluoride) (PVDF), an electroactive polymer with great potential for tissue engineering applications. Our results reveal significant differences in collagen affinity, conformation, and interaction strength depending on the electric charge of the PVDF surface, which subsequently affects the behaviour of mesenchymal stem cells seeded on them. These findings highlight the importance of surface charge in the establishment of the material-protein interface and ultimately in the biological response to the material. STATEMENT OF SIGNIFICANCE: The development of new tissue engineering strategies relies heavily on the understanding of how biomaterials interact with biological tissues. Although several factors drive this process and their driving principles have been identified, the relevance and mechanism by which the surface potential influences cell behaviour is still unknown. In our study, we investigate the interaction between collagen, the most abundant component of the extracellular matrix, and poly(vinylidene fluoride) with varying surface charges. Our findings reveal substantial variations in the binding forces, structure and adhesion of collagen on the different surfaces, which collectively explain the differential cellular responses. By exposing these differences, our research fills a critical knowledge gap and paves the way for innovations in material design for advanced tissue regeneration strategies.

Osseointegration commences with foreign body inflammation upon implant placement, where macrophages play a crucial role in the immune response. Subsequently, during the intermediate and late stages of osseointegration, mesenchymal stem cells (MSCs) migrate and initiate their osteogenic functions, while macrophages support MSCs in osteogenesis. The utilization of ferroelectric P(VDF-TrFE) covered ITO planar microelectrodes facilitated the simulation of various surface charge to investigate their effects on MSCs\' osteogenic differentiation and macrophage polarization and the results indicated a parabolic increase in the promotional effect of both with the rise in piezoelectric coefficient. Furthermore, the surface charge with a piezoelectric coefficient of -18 exhibited the strongest influence on the promotion of M1 polarization of macrophages and the promotion of MSCs\' osteogenic differentiation. The impact of macrophage polarization and MSC osteogenesis following the interaction of macrophages affected by surface charge and MSC was ultimately investigated. It was observed that macrophages affected by the surface charge of -18 piezoelectric coefficient still exerted the most profound induced osteogenic effect, validating the essential role of M1-type macrophages in the osteogenic differentiation of MSCs.

As promising prospects for renewable power harvesting, two-dimensional (2D) nanochannels for osmotic energy capture in a reverse electrodialysis arrangement have garnered significant attention. However, existing 2D nanochannel membranes have shown limited power generation capabilities due to challenges in balancing ion flux and selectivity. Here, we construct montmorillonite (MMT)/TEMPO-mediated oxidation cellulose nanofibers (TOCNFs) nanocomposite membranes for enhanced ion transmembrane transport. The intercalation of TOCNFs not only enlarges the interlayer distance, but also provides abundant space charge inside the nanochannels. Benefiting from the strong ion selectivity and high ion flux, the composite membrane achieves a remarkable power output of ∼16.57 W/m2 in the gradient of artificial seawater and river water, exceeding that of the state-of-the-art heterogeneous membrane-based osmotic energy conversion systems. Both experimental and theoretical findings confirm that the synergism of space and surface charge plays a crucial role in promoting osmotic energy conversion. This research contributes valuable insights into the optimization of 2D membranes for efficient clean energy harvesting purposes.

Platinum-based neural electrodes frequently alloyed with Ir or W are routinely used for the treatment of neurological conditions. However, their performance is hampered by impaired electrical contact between electrode and tissue that compromises long-term implant stability. Though there are multiple coating techniques available to address this issue, electrode, and base material often exhibit a compositional mismatch, which impairs mechanical stability and may lead to toxicological side effects. In this work we coated Pt wire electrodes with ligand-free electrostatically stabilized colloidal Pt90Ir10, Pt90W10, and Pt50W50 alloy nanoparticles (NPs) matching electrode compositions using electrophoretic deposition (EPD) with direct-current (DC) and pulsed-DC fields in aqueous medium. The generated alloy NPs exhibit a solid solution structure as evidenced by HR-TEM-EDX and XRD, though additional WOx phases were identified in the Pt50W50 samples. Consequently, coating efficiency was also impaired in the presence of high W mass fractions in the alloy NPs. Characterization of the NP coatings by cyclic voltammetry and impedance spectroscopy yielded a significant reduction of the impedance in the Pt90Ir10 sample in comparison to the Pt control. The electrochemical surface area (ECSA) of the PtW alloy coatings, on the other hand, was significantly reduced.

Per- and poly-fluoroalkyl substances (PFASs) are contaminants of emerging concern, yet the understanding of factors that control their leaching and release from contaminated soils remains limited. This study aimed to investigate the impact of dissolved organic carbon (DOC) on the release of PFASs-specifically, perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), and perfluorooctanoic acid (PFOA)from soils contaminated by aqueous film forming foam (AFFF). Batch aqueous leaching experiments were conducted on AFFF-contaminated soils under alkaline solution conditions (pH 9.5, 10.5, and 12) as it enhances leaching of both PFAS and DOC. Leaching of PFOS was significantly increased under alkaline conditions. Although the leaching of PFAS generally increased with pH, PFOS appeared to be more retained under the very alkaline pH conditions used in this study. At the same solution pH, leaching of PFOS and DOC was less in Ca(OH)2 than in NaOH. The retention of PFOS under these conditions may be attributable to the shielding of the negative charge of the soil components and colloids (e.g., DOC and clay minerals) in the leachates and/or the screening of negative charges on head groups of PFOS due to the high concentration of divalent cations. Solution chemistry affected desorption of PFOS more than PFHxS and PFOA. The study highlights that the influence of DOC on PFAS leaching and transport can be very complex, and depends on leachate chemistry (e.g., pH and cation type), PFAS chemistry, the magnitude of PFAS contamination and factors that influence the solid:liquid partitioning of organic carbon in soil.

The capability of dielectric measurements was significantly increased with the development of capacitive one-side access physical sensors. Complete samples give no opportunity to study electric susceptibility at a partial coverage of the one-side access sensor\'s active area; therefore, partial samples are proposed. The electric susceptibility at the partial coverage of a circular one-side access sensor with cylinders and shells is investigated for polyurethane materials. The implementation of the relative partial susceptibility permitted us to transform the calculated susceptibility data to a common scale of 0.0-1.0 and to outline the main trends for PU materials. The partial susceptibility, relative partial susceptibility, and change rate of relative partial susceptibility exhibited dependence on the coverage coefficient of the sensor\'s active area. The overall character of the curves for the change rate of the relative partial susceptibility, characterised by slopes of lines and the ratio of the change rate in the centre and near the gap, corresponds with the character of the surface charge density distribution curves, calculated from mathematical models. The elaborated methods may be useful in the design and optimization of capacitive OSA sensors of other configurations of electrodes, independent of the particular technical solution.

Biophysical and biochemical cues of biomaterials can regulate cell behaviors. Dental pulp stem cells (DPSCs) in pulp tissues can differentiate to odontoblast-like cells and secrete reparative dentin to form a barrier to protect the underlying pulp tissues and enable complete pulp healing. Promotion of the odontogenic differentiation of DPSCs is essential for dentin regeneration. The effects of the surface potentials of biomaterials on the adhesion and odontogenic differentiation of DPSCs remain unclear. Here, poly(vinylidene fluoride-trifluoro ethylene) (P(VDF-TrFE)) films with different surface potentials were prepared by the spin-coating technique and the contact poling method. The cytoskeletal organization of DPSCs grown on P(VDF-TrFE) films was studied by immunofluorescence staining. Using atomic force microscopy (AFM), the lateral detachment forces of DPSCs from P(VDF-TrFE) films were quantified. The effects of electrical stimulation generated from P(VDF-TrFE) films on odontogenic differentiation of DPSCs were evaluated in vitro and in vivo. The unpolarized, positively polarized, and negatively polarized films had surface potentials of -52.9, +902.4, and -502.2 mV, respectively. DPSCs on both negatively and positively polarized P(VDF-TrFE) films had larger cell areas and length-to-width ratios than those on the unpolarized films (P < 0.05). During the detachment of DPSCs from P(VDF-TrFE) films, the average magnitudes of the maximum detachment forces were 29.4, 72.1, and 53.9 nN for unpolarized, positively polarized, and negatively polarized groups, respectively (P < 0.05). The polarized films enhanced the mineralization activities and increased the expression levels of the odontogenic-related proteins of DPSCs compared to the unpolarized films (P < 0.05). The extracellular signal-regulated kinase (ERK) signaling pathway was involved in the odontogenic differentiation of DPSCs as induced by surface charge. In vivo, the polarized P(VDF-TrFE) films enhanced adhesion of DPSCs and promoted the odontogenic differentiation of DPSCs by electrical stimulation, demonstrating a potential application of electroactive biomaterials for reparative dentin formation in direct pulp capping.

Intracellular calcium ion detection is of great significance for understanding the cell metabolism and signaling pathways. Most of the current ionic sensors either face the size issue or sensitivity limit for the intracellular solution with high background ion concentrations. In this paper, we proposed a calmodulin (CaM) functionalized nanopore for sensitive and selective Ca2+ detection inside living cells. A salt gradient was created when the nanopore sensor filled with a low concentration electrolyte was in contact with a high background concentration solution, which enhanced the surface charge-based detection sensitivity. The nanopore sensor showed a 10 × sensitivity enhancement by application of a 100-fold salt gradient, and a detection limit of sub nM. The sensor had a wide detection range from 1 nM to 1 mM, and allowed for quick calcium ion quantification in a few seconds. The sensor was demonstrated for intracellular Ca2+ detection in A549 cells in response to ionomycin.