A rapid one-step process for the isolation of antibacterial peptides by silica-decorated Fe3O4nanoparticles

Extraction of antimicrobial peptides from pea protein hydrolysates by sulfonic acid functionalized biochar

The extraction methods for antimicrobial peptides (AMPs) from plants are varied, but the absence of a standardized and rapid technique remains a challenge. In this study, a functionalized biochar was developed and characterized for the extraction of AMPs from pea protein hydrolysates. The results indicated that the biochar mainly enriched AMPs through electrostatic interaction, hydrogen bonding and pore filling. Then three novel cationic antimicrobial peptides were identified, among which the RDLFK (Arg-Asp-Leu-Phe-Lys) had the greatest inhibitory effect against Staphylococcus aureus and Bacillus subtilis, showcasing IC50 value of 2.372 and 1.000 mg/mL, respectively. Additionally, it was found that RDLFK could damage bacterial cell membranes and penetrate the cells to inhibit DNA synthesis. These results provided that the biochar-based extraction method presents an efficient and promising avenue for isolating AMPs, addressing a critical gap in the current methodologies for their extraction from plant sources.

Biological Applications of Silica-Based Nanoparticles

Silica nanoparticles have been widely explored in biomedical applications, mainly related to drug delivery and cancer treatment. These nanoparticles have excellent properties, high biocompatibility, chemical and thermal stability, and ease of functionalization. Moreover, silica is used to coat magnetic nanoparticles protecting against acid leaching and aggregation as well as increasing cytocompatibility. This review reports the recent advances of silica-based magnetic nanoparticles focusing on drug delivery, drug target systems, and their use in magnetohyperthermia and magnetic resonance imaging. Notwithstanding, the application in other biomedical fields is also reported and discussed. Finally, this work provides an overview of the challenges and perspectives related to the use of silica-based magnetic nanoparticles in the biomedical field.

A Specific and Sensitive Aptamer-Based Digital PCR Chip for Salmonella typhimurium Detection

Food poisoning and infectious diseases caused by Salmonella typhimurium (S. typhimurium) are serious public health concerns for human health and food safety. The diversity and complexity of food matrices pose great challenges for rapid and ultra-sensitive detection of S. typhimurium in food samples. A method capable of identification, detection, and quantification of S. typhimurium is essential for addressing these issues. In this study, aptamer-coated magnetic beads (Apt-MBs) are employed as capture bio-probes to specifically and selectively concentrate S. typhimurium in food samples. A self-priming chip-based digital PCR was then presented as another biosensor for on-site detection and quantification of S. typhimurium cells. The chip we developed was robust and did not require any external power for sample loading. The combination of Apt-MBs with an on-chip digital detection realized the integration into lab-on-a-chip-based biosensors for on-site monitoring of foodborne pathogens. It was possible to capture and detect S. typhimurium cells as low as 90 CFU/reaction with a capture efficiency of 94.5%. Additionally, the whole process only took about 2 h. This unique platform could also be used to monitor other target bacteria with high specificity and sensitivity by utilizing different aptamers. Furthermore, the platform has potential applications in point-of-care testing in the future.