Carbon-based low-pressure filtration membrane for the dynamic disruption of bacteria from contaminated water

Nanofiber-based Multifunctional Microspheres for Rapid Hemostasis and Microorganism Removal of Water

Constructing hemostats capable of effectively controlling severe hemorrhage from irregular wounds presents significant challenges and imperatives. In this study, a novel approach is introduced using nanofibrous chitin microspheres (NCM) that are compressed to 60% strain (NCM-60%) to amplify their water-initiated expansion performance. This unique capacity allows NCM-60% to efficiently conform to and fill irregular bleeding cavities, even those of varying depths and curvatures, thereby promoting rapid blood coagulation at deep hemorrhage sites. NCM-60% exhibits effective control of severe femoral artery and "J"-shaped liver hemorrhages in 151 ± 6 s and 68 ± 15 s, respectively, revealing its exceptional hemostatic efficacy. Furthermore, NCM-60% exhibited promising capabilities in removing microbes from water, achieving removal rates of over 96% of bacteria. Blood compatibility assessments and cytotoxicity tests further confirmed the favorable biocompatibility of NCM-60%. Importantly, NCM-60% is found to biodegrade and be absorbed in vivo within 12 weeks. This study represents the first instance of leveraging chitin nanofiber-based biomaterials to design water-initiated expansion micro-hemostat, and integrate hemostatic functions with waterborne microorganism removal, thereby expanding the potential applications of micro-nanostructural materials in emergency first-aid scenarios.

Edible coating using carbon quantum dots for fresh produce preservation: A review of safety perspectives

Fresh produce deteriorates and spoils after harvest due to its perishable nature. Deterioration in quality over time has become a major problem for the food industry, placing an undue burden on the economy and agriculture. Food scientists have developed various methods and technologies to prevent spoilage of fruits and vegetables during storage and logistics. Utilizing carbon quantum dots (CQDs) in the form of active packaging and coatings has been a popular strategy recently. CQDs have recently attracted attention as sustainable and functional nanomaterials. CQDs are popular among food scientists due to their easy and economical synthesis, sustainability, non-toxicity, biocompatibility, edibility, UV protection, and antibacterial and antioxidant activities. Although many studies have been conducted and reviewed on the utilization of CQDs in the manufacture of flexible active packaging materials, relatively few studies have investigated the use of CQDs in edible coating formulations for fresh produce. The main reasons for this are concerns about the potential toxicity and edibility of CQDs if they are coated directly on fresh produce. Therefore, this review aims to address these issues by investigating the dose-dependent non-toxicity and biocompatibility of sustainable CQDs along with other important properties from a food packaging perspective. Additionally, this review focuses on the studies performed so far on the direct coating of CQD-based formulations on fresh and fresh-cut fruits and vegetables and discusses the important impact of CQDs on the quality of coated agricultural products. This review is intended to provide food packaging researchers with confidence and prospects for utilizing sustainable CQDs in direct coating formulations for food.

Facile and Green Synthesis of Novel Fluorescent Carbon Quantum Dots and Their Silver Heterostructure: An In Vitro Anticancer Activity and Imaging on Colorectal Carcinoma

Carbon dots (CQDs) have been widely investigated as prime candidates for developing a tumor theranostic platform due to their tunable fluorescence emission and excitation, high water solubility, good photostability, and biocompatibility. Among the CQDs, natural CQDs are an emerging class of nanomaterials in the carbon family. Herein, highly fluorescent carbon quantum dots (CQDs) were synthesized from orange juice using a one-step hydrothermal method and characterized by different techniques. After that, CQD/Ag heterostructures were synthesized by the reduction of silver salt, in particular silver nitrate (AgNO3) solution using sodium borohydride (NaBH4) in different ratios. The photostability and characterization of CQD/Ag heterostructures were investigated. At last, a comparative cellular toxicity measurement was done to select the superior CQD/Ag heterostructure in the human colorectal carcinoma (HCT 116) cell line along with the imaging property. The detailed cell death signaling was also observed in the HCT 116 cell line via the ROS-dependent mitochondrial-mediated pathway, where Akt (RAC-α serine/threonine-protein kinase) played a important role.

Mansonone G and its derivatives exhibit membrane permeabilizing activities against bacteria

In an era where the rate of bacteria evolving to be resistant to clinically-used antibiotics far exceeds that of antibiotic discovery, the search for new sources of antibacterial agents has expanded tremendously. In recent years, interest in plant-based natural products as promising sources of antibacterial agents has taken an upward trend. Mansonones, botanically-derived naphthoqionones, having many uses in Asian traditional medicine–including anti-infective roles–have sparked interest as a possible source of antibacterial agents. Here, we show that mansonone G, extracted from Mansonia gagei Drumm. heartwoods, possessed antibacterial activities towards Bacillus subtilis, Staphylococcus aureus and Escherichia coli lptD4213, inhibiting the growth of the bacteria at 15.6 μM, 62.5 μM and 125 μM, respectively. Fourteen derivatives of mansonone G were synthesized successfully and were found to have a similar antibacterial spectrum to that of the parent compound, with some derivatives possessing improved antibacterial activities. Bacterial cytological profiling analysis showed that mansonone G harbors membrane permeabilizing activities against B. subtilis and E. coli lptD4213. Temporal analysis of SYTOX Green staining among individual cells showed that mansonone G rapidly permeabilized bacterial membrane within 10 min, with SYTOX Green intensity reaching 13-fold above that of the control. Collectively, these findings highlight the importance of mansonone G and its derivatives as potential antibacterial agents, paving the way for further modifications in order to improve their antibacterial spectrum.

Room Temperature Fabrication of Macroporous Lignin Membranes for the Scalable Production of Black Silicon

Rising global demand for biodegradable materials and green sources of energy has brought attention to lignin. Herein, we report a method for manufacturing standalone lignin membranes without additives for the first time to date. We demonstrate a scalable method for macroporous (∼100 to 200 nm pores) lignin membrane production using four different organosolv lignin materials under a humid environment (>50% relative humidity) at ambient temperatures (∼20 °C). A range of different thicknesses is reported with densely porous films observed to form if the membrane thickness is below 100 nm. The fabricated membranes were readily used as a template for Ni²⁺ incorporation to produce a nickel oxide membrane after UV/ozone treatment. The resultant mask was etched via an inductively coupled plasma reactive ion etch process, forming a silicon membrane and as a result yielding black silicon (BSi) with a pore depth of >1 μm after 3 min with reflectance <3% in the visible light region. We anticipate that our lignin membrane methodology can be readily applied to various processes ranging from catalysis to sensing and adapted to large-scale manufacturing.