Search Results (347)

In this work, a novel approach for the catalytic reduction of 4-nitrophenol to 4-aminophenol using sodium borohydride is proposed. It was shown that a continuous-flow microreactor system is an optimal tool for PdNP synthesis with dimensions of 3.0 ± 0.5 nm, as well as the performance of catalytic tests with high process efficiency, while keeping a high level of safety. The results obtained from the microreactor system allowed for 100% conversion to 4-aminophenol and were compared to processes carried out in a batch reactor, as well as to a hybrid system which was a combination of a microreactor (synthesis of PdNPs) and batch reactor (catalytic test). These investigations were enhanced by kinetic studies, for which a stopped-flow spectrophotometer was applied due to the extremely high rate of the reaction, i.e., formation of PdNPs (2.1 s), as well as to measure in situ the rate of the heterogeneous catalytic process. To visualize the progress of the heterogeneous reaction more precisely, color coding based on transmittance measurements was employed. Furthermore, to deepen the understanding of the process, a detailed mechanism supported by DFT calculations for the conversion of 4-nitrophenol to 4-aminophenol in the presence of PdNPs was proposed. Full article

The design of sustainable nanomaterials for catalysis is a key challenge in green chemistry. Herein, we report the synthesis of halloysite nanotube (Hal)-based nanomaterials selectively functionalized with a bio-inspired polydopamine (PDA) coating, which enables the controlled anchoring of palladium and copper nanoparticles (PdNPs and CuNPs). This mild and ecofriendly strategy yields highly dispersed and ultrasmall (<5 nm) metal nanoparticles without the need for surfactants or harsh reagents. The resulting materials, Hal@PDA/PdNPs and Hal@PDA/CuNPs, were evaluated in two well-established model reactions commonly employed to probe catalytic performance: cinnamaldehyde hydrogenation and 4-nitrophenol reduction. Hal@PDA/PdNPs displayed complete conversion and >90% selectivity toward hydrocinnamaldehyde at low Pd loading (0.8 wt%) and maintained its efficiency over six catalytic cycles (TOF up to 0.1 s⁻¹), while Hal@PDA/CuNPs retained high activity through eight consecutive runs in the reduction of 4-nitrophenol. Hal@PDA/CuNPs proved to be an excellent recyclable catalyst for the reduction of 4-nitrophenol, retaining high activity through eight consecutive runs. Overall, this study introduces a robust and modular approach to fabricating halloysite-based nanocatalysts, demonstrating their potential as green platforms for metal nanoparticle-mediated transformation. Full article

Natural product (NP) use by patients alongside their conventional cancer therapies is ubiquitous. This common, yet often hidden, practice can potentially contribute to significant patient harm, given the narrow therapeutic window of most anticancer drugs. This review takes on this challenge directly, moving past theoretical concerns to summarize current clinical evidence on interactions between widely used NPs and modern cancer treatments, including chemotherapy, targeted therapy, and immunotherapy. We break down the key pharmacokinetic (PK) mechanisms, such as the disruption of cytochrome P450 enzymes, and the pharmacodynamic (PD) effects that can either help or hinder treatment. By examining both well-established clinical interactions and those supported by preliminary or preclinical findings, we highlight how NPs may alter the effectiveness of anticancer medications and where evidence remains uncertain. Lack of reliable safety information for NPs along with widespread use of these products by patient populations has the potential to impact clinical care and patient outcomes significantly, frequently causing harm. We advocate for improved patient-provider communication and additional evidence-based research to address this gap in literature. The majority of reported interactions are based on preclinical or limited clinical evidence. A more rigorous evidence base including real-world data and clinical trials is urgently needed to guide practice. Full article

The LRRK2+ SAA− cohort of Parkinson’s disease (PD), characterized by the absence of hallmark α-synuclein pathology, remains under-explored. This limits opportunities for early detection and targeted intervention. This study analyzes data from this under-characterized subgroup and compares it with the LRRK2+ SAA+ cohort using longitudinal data from the Parkinson’s Progression Markers Initiative (PPMI). The PPMI dataset includes 115 LRRK2+ patients (70 SAA+, 45 SAA−) across 52 features encompassing clinical assessments, cognitive scores, DaTScan SPECT imaging, and motor severity. DaTScan binding ratios were selected as imaging-based indicators of early dopaminergic loss, while NP3TOT (MDS-UPDRS Part III total score) was used as a gold-standard clinical measure of motor symptom severity. Linear mixed-effects models were then applied to evaluate longitudinal predictors of DaTScan decline and NP3TOT progression, and statistical analyses of group comparisons revealed distinct drivers of symptoms differentiating SAA− from SAA+ patients. In SAA− patients, a decline in DaTScan was significantly associated with thermoregulatory impairment (p-value = 0.019), while NP3TOT progression was predicted by constipation (p-value = 0.030), sleep disturbances (p-value = 0.046), and longitudinal time effects (p-value = 0.043). In contrast, SAA+ patients showed significantly lower DaTScan values compared to SAA− (p-value = 0.0004) and stronger coupling with classical motor impairments, including freezing of gait (p-value = 0.016), rising from a chair (p-value = 0.007), and turning in bed (p-value = 0.016), along with cognitive decline (MoCA clock-hands test, p-value = 0.037). These findings support the hypothesis that LRRK2+ SAA− patients follow a distinct pathophysiological course, where progression is influenced more by autonomic and non-motor symptoms than by typical motor dysfunction. This study establishes a robust, multimodal modeling framework for examining heterogeneity in genetic PD and highlights the utility of combining DaTScan, NP3TOT, and symptom-specific features for early subtype differentiation. These findings have direct clinical implications, as stratifying LRRK2 carriers by SAA status may enhance patient monitoring, improve prognostic accuracy, and guide the design of targeted clinical trials for disease-modifying therapies. Full article

Background/Objectives: Covalent conjugation of an antibiotic vancomycin (VCM) moiety and a photosensitizing mesochlorin (mChl_Pd) unit into one molecular entity may present the potential to produce the combinatorial effect of both antibacterial photodynamic therapeutic (aPDT) and antibiotic activities. Our recent study indicated that a short linkage of <4 (C−C/or C−N) bond distances between these two moieties resulted in significant steric hindrance due to the bulky VCM, which greatly reduces the accessibility of the agent to the cell surface of methicillin-resistant Staphylococcus aureus (MRSA). The observed aPDT efficacy was found to be minimal. Here, we report that the revision of this linkage, via an EG₁₀ unit using identical synthetic procedures, was able to resolve the issue. Methods: Accordingly, the corresponding combinatorial aPDT−antibiotic compound, consisting of two covalently bonded quaternary ammonium pentacationic arms on the mesochlorin chromophore core, designated as VCMe-mChl_Pd-N₁₀⁺ (LC40e⁺), was prepared for applications in antibacterial photodynamic inactivation (aPDI) activity. It was selected to investigate its enhanced binding and targeting ability to the surface of Gram-positive MRSA cells. Subsequent antibacterial photodynamic therapeutic (aPDT) activity to inactivate MRSA was investigated to substantiate the corresponding cell-surface binding effect on the efficacy of aPDT. Results: We found that the covalent combination of 10 positive charges and an MRSA-targeting vancomycin (VCM) moiety in a conjugated structure, functioning as an antibiotic–decacationic photosensitizing agent (Abx-dcPS), was capable of largely improving the MRSA cell-targeting efficiency. Importantly, variation in the chain length of the oligo(ethylene glycol) linker of VCMe-mChl_Pd-N₁₀⁺, which was sufficiently long enough to properly separate the photoactive mesochlorin ring moiety from the VCM moiety within the molecular structure, resulted in significantly enhanced aPDT activity. The new conjugate provided nearly complete eradication (>6.5-log₁₀ colony-forming units (CFU) reduction) of MRSA cells in vitro. The aPDT efficacy followed the order Abx-dcPS (combinatorial decacationic) > dcPS (decacationic) >> nPS (nonionic). This order was also verified by the relative physical binding trend of these PSs using either nPS-, dcPS-, or Abx-dcPS-pretreated and pre-fixed MRSA cells in investigations of fluorescent confocal microscopy, UV–vis fluorescence spectroscopy, and transmission electron microscopy (TEM). Conclusions: Furthermore, the molecular conjugate of Abx-dcPS may provide covalent co-delivery of two drug components concurrently, which might also serve as an effective antibiotic agent after aPDT and potentially prevent the reoccurrence of MRSA-induced infection. Full article

Environmental contamination is a critical global concern, primarily due to detrimental greenhouse gas (GHG) emissions, especially carbon dioxide (CO₂), which significantly contribute to climate change. Moreover, the presence of harmful heavy metals like Ni, Cd, Cu, Hg, and Pb in soil and water ecosystems has led to poor water quality. Noble metal nanoparticles (MNPs), for instance, Pd, Ag, Pt, and Au, have emerged as promising solutions for addressing environmental pollution. However, the practical utilization of MNPs faces challenges as they tend to aggregate and lose stability. To overcome this issue, the reverse double-solvent method (RDSM) was utilized to synthesis melamine-based porous polyaminals (POPs) as a supportive material for the in situ growing of silver nanoparticles (Ag NPs). The porous structure of melamine-based porous polyaminals, featuring aminal-linked (-HN-C-NH-) and triazine groups, provides excellent binding sites for capturing Ag⁺ ions, thereby improving the dispersion and stability of the nanoparticles. The resulting material exhibited ultrafine particle sizes for Ag NPs, and the incorporation of Ag NPs within the porous polyaminals demonstrated a high surface area (~279 m²/g) and total pore volume (1.21 cm³/g), encompassing micropores and mesopores. Additionally, the Ag NPs@POPs showcased significant capacity for CO₂ capture (2.99 mmol/g at 273 K and 1 bar) and effectively removed Cu (II), with a remarkable removal efficiency of 99.04%. The nitrogen-rich porous polyaminals offer promising prospects for immobilizing and encapsulating Ag nanoparticles, making them outstanding adsorbents for selectively capturing carbon dioxide and removing metal ions. Pursuing this approach holds immense potential for various environmental applications. Full article

The development of heterogeneous nanocatalysts with high performance is essential for improving hydrogen production through formic acid dehydrogenation, but challenging. Herein, highly dispersed Pd nanoparticles (NPs) were successfully immobilized on porous nitrogen-doped carbon cages (PNCCs) derived from zeolitic imidazole frameworks. By virtue of the synergistic effect, the optimized Pd/PNCC nanocatalytic systems exhibit an excellent catalytic kinetics toward catalyzing FA dehydrogenation with a turnover frequency (TOF) value as high as 3174 h⁻¹ at 323 K, which is 59 times relative to that of Pd nanoparticles. The exceptional activity may be ascribed to the PNCC solid support may induce a strong electronic metal–support interaction to optimize the electron configuration of Pd active sites and accelerate the kinetics of O-H bond cleavage, resulting in an enhanced catalytic performance toward FA dehydrogenation. This work will supply a novel strategy for the development of supported nanocatalysts with high performance for tremendous catalytic applications in the future. Full article

Background/Objectives: The conventional treatment of glioblastoma (GBM) with alkylating agents is not curative. The protein O6-methylguanine DNA methyltransferase (MGMT) is a significant limitation, being able to repair drug-induced DNA damage. Thus, exploring non-alkylating agents already approved by the FDA is imperative. The antidepressant fluoxetine (FL) has been explored due to its anti-cancer properties. However, its first-pass effect and its non-targeted distribution to brain tissue are major limitations of FL’s administration, which is conventionally orally administered. Thus, the primary objective of this work was the development of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) tailored with folic acid (FA) for FL delivery to GBM cells. Methods: A Central Composite Design (CCD) was applied to optimize the NPs. Results: The developed FA-functionalized PLGA NPs exhibited physicochemical properties suitable for brain-targeted delivery. The final formulation presented an average diameter of 167 ± 8 nm, a polydispersity index (PdI) of 0.23 ± 0.07, and a zeta potential of −22.2 ± 0.3 mV. The encapsulation efficiency (EE) and loading capacity (LC) values were 44.4 ± 3.8% and 3.1 ± 0.3%, respectively. In vitro studies demonstrated that the NPs are stable in storage and simulated physiological conditions and can maintain a controlled and slow-release profile of FL for 17 days. In vitro cell uptake experiments demonstrated that conjugation with FA enhances the NPs’ internalization in GBM cells overexpressing folate receptors through endocytosis mediated by this receptor. Furthermore, in vitro cytotoxicity experiments demonstrated that the FL encapsulation in the developed NPs maintains drug efficacy, as well as it was able to increase cell sensitivity to treatment with an alkylating agent. Conclusions: These results suggest that the developed NPs are effective nanocarriers, either as a standalone therapy or as a chemosensitizer in combination with the standard GBM treatment. Full article

Excessive use of antibiotics can lead to antibiotic resistance, posing a significant threat to human health and the environment. Chloramphenicol (CAP), once widely used, has been banned in many regions for over 20 years due to its toxicity. Detecting CAP residues in food products is crucial for regulating safe use and preventing unnecessary antibiotic exposure. Electrochemical sensors are low-cost, sensitive, and easily detect CAP. This paper reviews recent research on electrochemical sensors for CAP detection, with a focus on the materials and fabrication techniques employed. The sensors are evaluated based on key performance parameters, including limit of detection, sensitivity, linear range, selectivity, and the ability to perform simultaneous detection. Specifically, we highlight the use of metal and carbon-based electrode modifications, including gold nanoparticles (AuNPs), nickel–cobalt (Ni-Co) hollow nano boxes, platinum–palladium (Pt-Pd), graphene (Gr), and covalent organic frameworks (COFs), as well as molecularly imprinted polymers (MIPs) such as polyaniline (PANI) and poly(o-phenylenediamine) (P(o-PD)). The mechanisms by which these modifications enhance CAP detection are discussed, including improved conductivity, increased surface-to-volume ratio, and enhanced binding site availability. The reviewed sensors demonstrated promising results, with some exhibiting high selectivity and sensitivity, and the effective detection of CAP in complex sample matrices. This review aims to support the development of next-generation sensors for antibiotic monitoring and contribute to global efforts to combat antibiotic resistance. Full article

This review examines the emerging role of manganese-based nanoparticles (Mn-NPs) in detecting heavy metal pollutants in environmental matrices. Heavy metals such as cadmium, lead, zinc, and copper pose serious environmental and health concerns due to their tendency to persist in ecosystems and accumulate in living organisms. As a result, there is a growing need for reliable methods to detect and remove these pollutants. Manganese nanoparticles offer unique advantages that scientists could consider as replacing other metal nanoparticles, which may be more expensive or more toxic. The physicochemical properties of Mn-NPs—including their multiple oxidation states, magnetic susceptibility, catalytic capabilities, and semiconductor conductivity—enable the development of multi-modal sensing platforms with exceptional sensitivity and selectivity. While Mn-NPs exhibit inherently low electrical conductivity, strategies such as transition metal doping and the formation of composites with conductive materials have successfully addressed this limitation. Compared to noble metal nanoparticles (Au, Ag, Pd) and other base metal nanoparticles (Bi, Fe₃O₄), Mn-NPs demonstrate competitive performance without the drawbacks of high cost, complex synthesis, poor distribution control, or significant aggregation. Preliminary studies retrieved from the Scopus database highlight promising applications of manganese-based nanomaterials in electrochemical sensing of heavy metals, with recent developments showing detection limits in the sub-ppb range. Future research directions should focus on addressing challenges related to scalability, cost-effectiveness, and integration with existing water treatment infrastructure to accelerate the transition from laboratory findings to practical environmental applications. Full article

The methanol oxidation reaction (MOR) of direct methanol fuel cells (DMFCs) is limited by the slow kinetic process and high reaction energy barrier, significantly restricting the commercial application of DMFCs. Therefore, developing MOR catalysts with high activity and stability is very important. In this paper, oxygen-functionalised activated carbon (FAC) with controllable oxygen-containing functional groups was prepared by adjusting the volume ratio of H₂SO₃/HNO₃ mixed acid, and Pd/AC and Pd/FAC catalysts were synthesised via the hydrazine hydrate reduction method. A series of characterisation techniques and electrochemical performance tests were used to study the catalyst. The results showed that when V(H₂SO₃):V(HNO₃) = 2:3, more defects were generated on the surface of the AC, and more oxygen-containing functional groups represented by C=O and C–OH were attached to the surface of the support, which increased the anchor sites of Pd and improved the dispersion of Pd nanoparticles (Pd NPs) on the support. At the same time, the mass–specific activity of Pd/FAC for MOR was 2320 mA·mg_Pd, which is 1.5 times that of Pd/AC, and the stability was also improved to a certain extent. In situ infrared spectroscopy further confirmed that oxygen functionalisation treatment promoted the formation and transformation of *COOH intermediates, accelerated the transformation of CO_L into CO_B, reduced the poisoning of CO_ads species adsorbed to the catalyst, optimised the reaction path and improved the catalytic kinetic performance. Full article

(1) Background: Although the field of natural product (NP) drug discovery has been extensively developed, there are still several bottlenecks hindering the development of drugs from NPs. The PD-1/PD-L1 immune checkpoint axis plays a crucial role in immune response regulation. Therefore, drugs targeting this axis can disrupt the interaction and enable immune cells to continue setting up a response against the cancer cells. (2) Methods: We have explored the immuno-oncological activity of NPs targeting the PD-1/PD-L1 immune checkpoint by estimating the half maximal inhibitory concentration (IC₅₀) through molecular docking scores and predicting it using machine learning (ML) models. The LightGBM (Light Gradient-Boosted Machine), a tree-based ML technique, emerged as the most effective approach and was used for building the quantitative structure–activity relationship (QSAR) classification model. (3) Conclusions: The model incorporating 570 spectral descriptors from NMR SPINUS was selected for the optimization process, and this approach yielded results for the external test set with a sensitivity of 0.74, specificity of 0.81, overall predictive accuracy of 0.78, and Matthews correlation coefficient (MCC) of 0.55. The strategy used here for estimating the IC₅₀ from docking scores and predicting it through ML models appears to be a promising approach for pure compounds. Nevertheless, further optimization is indicated, particularly through the simulation of the spectra of mixtures by combining the spectra of individual compounds. Full article

Hexavalent chromium [Cr(VI)] is a hazardous environmental contaminant, and palladium nanoparticles (PdNPs) have shown promise as catalysts for its reduction. This study explores the primary factor influencing the catalytic performance of PdNPs in Cr(VI) reduction by investigating the crystal structure and composition of PdNPs in fungal-based catalysts. Five Pd-loaded catalysts were synthesized by treating fungal biomass with different chemical reagents, resulting in varying Pd(0) contents. The nanoparticle morphology, chemical states, and functional group interactions during Pd adsorption and reduction were investigated using multiple analytical techniques. The results showed that fungal hyphae remained structurally intact throughout the treatment process. PdNPs smaller than 2 nm were observed, with both Pd(0) and PdO present. The proportion of Pd(0) ranged from 6.4% to 37.2%, depending on the chemical reagent used. In addition, functional groups such as phosphate, amine, hydroxyl, and carboxyl were found to play key roles in palladium binding, underscoring the importance of surface chemistry in the adsorption and reduction process. A strong positive correlation was observed between the Pd(0) content and catalytic activity. Notably, the NCPdSF sample (palladium-loaded biomass treated with sodium formate) exhibited the highest Pd(0) content of 59.2% and achieved the most effective Cr(VI) reduction. These results suggest that Pd(0) content is a key determinant of catalytic efficiency in Cr(VI) reduction and that optimizing chemical treatments to enhance Pd(0) levels can substantially improve catalyst performance. Full article

Supported Pd-based catalysts have been widely applied in the hydrogenation of specific functional groups. Recent trends have focused on employing Pd-based heterogeneous catalysts supported on inorganic nanotubes, wherein inner surface functionalization modulates both palladium nanoparticle (Pd-NP) dispersion and the interaction between reactants and the catalyst surface, thereby influencing catalytic properties. This study aims to develop a catalytic system using amine-lumened halloysite nanotubes immobilizing Pd-NPs (Pd/HNTA) as catalysts for hydrogenation reactions. The formation of Pd-NPs within the organo-functionalized lumen—modified by 3-aminopropyltrimethoxysilane—is confirmed by transmission electron microscopy (TEM) imaging, which reveals a particle size of 2.2 ± 0.4 nm. For comparison, Pd-NPs supported on pristine halloysite (Pd/HNTP) were used as control catalysts, displaying a metal particle size of 2.8 ± 0.8 nm and thereby demonstrating the effect of organic functionalization on the halloysite nanotubes. Both catalysts were employed in the hydrogenation of furfural (FUR) and nitrobenzene (NB) as model reactions. Pd/HNTA demonstrated superior catalytic performance for both substrates, with TOF values of 880 h⁻¹ for FUR and 946 h⁻¹ for NB, and selectivities exceeding 98% for tetrahydrofurfuryl alcohol (THFOH) and aniline (AN), respectively. However, recyclability studies displayed that Pd/HNTA was deactivated at the 10 catalytic cycles during the hydrogenation of FUR, whereas, in the hydrogenation of NB, 5 catalytic cycles were achieved with maximum conversion and selectivity at 360 min. These results revealed that the liquid-phase environment plays a pivotal role in catalyst stability. In the hydrogenation of NB, the coproduction of H₂O adversely affects the interaction between the Pd particles and the inner amine-modified surface, increasing the deactivation of the catalyst with reuse. Thus, the Pd/HNTA catalyst holds significant promise for the development of noble-metal-based catalysts and their application in the transformation of other reducible organic functional groups via hydrogenation reaction. Full article

This study presents a sustainable, environmentally friendly synthetic route for the production of key intermediates in losartan using palladium nanoparticles (PdNPs) derived from a brown seaweed, Sargassum incisifolium, as a recyclable nanocatalyst. A key intermediate, biaryl, was synthesized with an excellent yield (98%) via Suzuki–Miyaura coupling between 2-bromobenzonitrile and 4-methylphenylboronic acid, catalyzed using bio-derived PdNPs under mild conditions. Subsequent bromination using N-bromosuccinimide (NBS) under LED light, followed by imidazole coupling and tetrazole ring formation, allowed for the production of losartan with an overall yield of 27%. The PdNP catalyst exhibited high stability and recyclability, as well as strong catalytic activity, even at lower loadings, and nitrosamine formation was not detected. While the overall yield was lower than that of traditional industrial methods, this was due to the deliberate avoidance of the use of toxic reagents, hazardous solvents, and protection/deprotection steps commonly used in conventional routes. This trade-off marks a shift in pharmaceutical process development, where environmental and safety considerations are increasingly prioritized in line with green chemistry and regulatory frameworks. This study provides a foundation for green scaling up strategies, incorporating sustainability principles into drug synthesis. Full article