While binder jetting (BJ) additive manufacturing (AM) holds considerable promise for industrial applications, defects often compromise part quality. This study addresses these challenges by investigating binding mechanisms and analyzing common defects, proposing tailored solutions to mitigate them. Emphasizing defect identification for effective quality control in BJ-AM, this research offers strategies for in-process rectification and post-process evaluation to elevate part quality. It shows how to successfully process metallic parts with complex geometries while maintaining consistent material properties. Furthermore, the paper explores the microstructure of AISI M2 tool steel, utilizing advanced image processing techniques like digital image analysis and SEM images to evaluate carbide distribution. The results show that M2 tool steel has a high proportion of M6C carbides, with furnace-cooled samples ranging from ~2.4% to 7.1% and MC carbides from ~0.4% to 9.4%. M6C carbides ranged from ~2.6% to 3.8% in air-cooled samples, while water-cooled samples peaked at ~8.52%. Sintering conditions also affected shrinkage, with furnace-cooled samples showing the lowest rates (1.7 ± 0.4% to 5 ± 0.4%) and water-cooled samples showing the highest (2 ± 0.4% to 14.1 ± 0.4%). The study recommends real-time defect detection systems with autonomous corrective capabilities to improve the quality and performance of BJ-AM components.

The existing aptamers for cadmium (Cd2+), the common toxic heavy metal contaminant in food, cannot meet the requirements for detecting Cd2+ in rapid detection methods. In previous work, we found that coupling aptamer-peptide conjugates (APCs) with peptides and aptamers can provide a less disruptive method with a significantly improved affinity. Moreover, we found that the spatial conformation of aptamers and peptides is crucial for obtaining proper affinity in APC. Therefore, we describe a simple design strategy to obtain a series of APCs with different affinities by designing peptide orientations (N-terminal, C-terminal). The best affinity was found for APC(C1-N) with a binding constant (Ka) of 2.23 × 106 M-1, indicating that the APC(C1-N) affinity was significantly increased by 829.17% over aptamer. Finally, a rolling-circle amplification (RCA)-coupled ratio fluorescence-based biosensor for Cd2+ detection was established with a detection limit of 0.0036 nM, which has great potential for practical aquatic product detection.

Recently, owing to the good calcium bioavailability, peptide-calcium chelates made of various foods have been emerging. Hericium erinaceus, an edible fungus, is rich in proteins with a high proportion of calcium-binding amino acids. Thus, mushrooms serve as a good source to prepare peptide-calcium chelates. Herein, the conditions for hydrolyzing Hericium erinaceus peptides (HP) with a good calcium-binding rate (CBR) were investigated, followed by the optimization of HP-calcium chelate (HP-Ca) preparation. Furthermore, the structure of the new chelates was characterized along with the evaluation of gastrointestinal stability and calcium absorption. Papain and a hydrolysis time of 2 h were selected for preparing Hericium erinaceus peptides, and the conditions (pH 8.5, temperature 55°C, time 40 min, and mass ratio of peptide/CaCl2 4:1) were optimal to prepare HP-Ca. Under this condition, the chelates contained 6.79 ± 0.13% of calcium. The morphology and energy disperse spectroscopy (EDS) analysis showed that HP-Ca was loose and porous, with an obvious calcium element signal. The ultraviolet-visible (UV) absorption and Fourier transform infrared spectroscopy (FT-IR) analysis indicated that calcium possibly chelates to HP via interaction with free -COO- from acidic amino acids and C = O from amide. HP-Ca displayed good stability against stimulated gastrointestinal digestion. Moreover, HP-Ca significantly improved the calcium absorption by Caco-2 epithelial cells. Thus, HP-Ca is a promising Ca supplement with high calcium bioavailability.

Currently, the binding of iron-binding protein transferrin (TF) with NPs and their interaction mechanisms have not been completely elucidated yet. Here, we probed the conformation-dependent release of Fe ions from TF induced by nano-sized polystyrene plastics (PS-NPs) using dialysis, ICP-MS, multi-spectroscopic techniques, and computational simulation. The results showed that the release of free Fe ions from TF was activated after PS-NPs binding, which displayed a clear dose-effect correlation. PS-NPs binding can induce the unfolding and loosening of polypeptide chain and backbone of TF. Alongside this we found that the TF secondary structure was destroyed, thereby causing TF protein misfolding and denaturation. In parallel, PS-NPs interacted with the chromophores, resulting in the occurrence of fluorescence sensitization effects and the disruption of the surrounding micro-environment of aromatic amino acids. Also, the binding of PS-NPs induced the formation of new aggregates in the PS-NPs-TF system. Further simulations indicated that PS-NPs exhibited a preference for binding to the hinge region that connects the C-lobe and N-lobe, which is responsible for the Fe ions release and structural alterations of TF. This finding provides a new understanding about the regulation of the release of Fe ions of iron-loaded TF through NPs-induced conformational and structural changes.

The coexistence of cadmium (Cd(II)) and arsenate (As(V)) pollution has long been an environmental problem. Biochar, a porous carbonaceous material with tunable functionality, has been used for the remediation of contaminated soils. However, it is still challenging for the dynamic quantification and mechanistic understanding of the simultaneous sequestration of multi-metals in biochar-engineered environment, especially in the presence of anions. In this study, ferrihydrite was coprecipitated with biochar to investigate how ferrihydrite-biochar composite affects the fate of heavy metals, especially in the coexistence of Cd(II) and As(V). In the solution system containing both Cd(II) and As(V), the maximum adsorption capacities of ferrihydrite-biochar composite for Cd(II) and As(V) reached 82.03 µmol/g and 531.53 µmol/g, respectively, much higher than those of the pure biochar (26.90 µmol/g for Cd(II), and 40.24 µmol/g for As(V)) and ferrihydrite (42.26 µmol/g for Cd(II), and 248.25 µmol/g for As(V)). Cd(II) adsorption increased in the presence of As(V), possibly due to the changes in composite surface charge in the presence of As(V), and the increased dispersion of ferrihydrite by biochar. Further microscopic and mechanistic results showed that Cd(II) complexed with both biochar and ferrihydrite, while As(V) was mainly complexed by ferrihydrite in the Cd(II) and As(V) coexistence system. Ferrihydrite posed vital importance for the co-adsorption of Cd(II) and As(V). The different distribution patterns revealed by this study help to a deeper understanding of the behaviors of cations and anions in the natural environment.

This study investigated effects of insoluble dietary fiber (IDF) from wheat bran on starch digestion in vitro, analyzed the inhibition kinetics of IDF toward α-amylase and discussed the underlying mechanisms. Digestion results showed IDF significantly retarded starch digestion with reduced digestion rate and digestible starch content. Enzyme inhibition kinetics indicated IDF was a mixed-type inhibitor to α-amylase, because IDF could bind α-amylase, as evidenced by confocal laser scanning microscopy. Fluorescence quenching and UV-vis absorption experiments conformed this, found IDF led to static fluorescence quenching of α-amylase, mainly through van der Waals and/or hydrogen bonding forces. This interaction induced alternations in α-amylase secondary structure, showing more loosening and misfolding structures. This may prevent the active site of enzyme from capturing substrates, contributing to reduced α-amylase activity. These results would shed light on the utilization of IDF in functional foods for the management of postprandial blood glucose.

Lead contamination is a major concern in food safety and, as such, many lead detection methods have been developed, especially aptamer-based biosensors. However, the sensitivity and environmental tolerance of these sensors require improvement. A combination of different types of recognition elements is an effective way to improve the detection sensitivity and environmental tolerance of biosensors. Here, we provide a novel recognition element, an aptamer-peptide conjugate (APC), to achieve enhanced affinity of Pb2+. The APC was synthesized from Pb2+ aptamers and peptides through clicking chemistry. The binding performance and environmental tolerance of APC with Pb2+ was studied through isothermal titration calorimetry (ITC); the binding constant (Ka) was 1.76*106 M-1, indicating that the APC\'s affinity was increased by 62.96% and 802.56% compared with the aptamers and peptides, respectively. Besides, APC demonstrated better anti-interference (K+) than aptamer and peptide. Through the molecular dynamics (MD) simulation, we found that more binding sites and stronger binding energy between APC with Pb2+are the reasons for higher affinity between APC with Pb2+. Finally, a carboxyfluorescein (FAM)-labeled APC fluorescent probe was synthesized and a fluorescent detection method for Pb2+ was established. The limit of detection of the FAM-APC probe was calculated to be 12.45 nM. This detection method was also applied to the swimming crab and showed great potential in real food matrix detection.

Gas therapy has been proven to be a promising and advantageous treatment option for cancers. Studies have shown that nitric oxide (NO) is one of the smallest structurally significant gas molecules with great potential to suppress cancer. However, there is controversy and concern about its use as it exhibits the opposite physiological effects based on its levels in the tumor. Therefore, the anti-cancer mechanism of NO is the key to cancer treatment, and rationally designed NO delivery systems are crucial to the success of NO biomedical applications. This review summarizes the endogenous production of NO, its physiological mechanisms of action, the application of NO in cancer treatment, and nano-delivery systems for delivering NO donors. Moreover, it briefly reviews challenges in delivering NO from different nanoparticles and the issues associated with its combination treatment strategies. The advantages and challenges of various NO delivery platforms are recapitulated for possible transformation into clinical applications.

Targeting RNA with small molecules is a major challenge of current medicinal chemistry, and the identification and design of original scaffolds able to selectively interact with an RNA target remains difficult. Various approaches have been developed based on classical medicinal chemistry strategies (fragment-based drug design, dynamic combinatorial chemistry, HTS or DNA-encoded libraries) as well as on advanced structural biology and biochemistry methodologies (such as X-ray, cryo-EM, NMR, or SHAPE). Here, we report the de novo design, synthesis, and biological evaluation of RNA ligands by using a straightforward and sustainable chemistry combined with molecular docking and biochemical and biophysical studies that allowed us to identify a novel pharmacophore for RNA binding. Specifically, we focused on targeting the biogenesis of microRNA-21, the well-known oncogene. This led us not only to promising inhibitors but also to a better understanding of the interactions between the small-molecule compounds and the RNA target paving the way for the rational design of efficient inhibitors with potential anticancer activity.

The excessive accumulation of potentially toxic metals (Pb and Cd) in coastal wetlands is among the main factors threatening wetland ecosystems. However, the effects of water table depth (WTD) on the risk and binding mechanisms of potentially toxic metals in sediments remain unclear. Here, sediments from different WTD obtained from a typical coastal wetland were evaluated using a newly developed strategy based on chemical extraction methods coupled with high-resolution spectroscopy. Our findings indicated that the WTD of the coastal wetland fluctuates frequently and the average enrichment factor for Pb was categorized as minor, whereas Cd enrichment was categorized as moderate. High-resolution spectroscopy techniques also demonstrated that organic functional groups and partly inorganic compounds (e.g., Fe-O/Si-O) played a vital role in the binding of Pb and Cd to surface sediments. Additionally, mineral components rather than organic groups were mainly bound to these metals in the bottom sediments. Collectively, our findings provide key insights into the potential health effects and binding characteristics of potentially toxic metals in sediments, as well as their dynamic behavior under varying sediment depths at a microscale.