In vitro somatic embryo productions from Curculigo orchioides derived gold nanoparticles: Synthesis, characterization, its biomedical applications, and their eco-friendly approaches to degradation of methylene blue under solar light irradiations

Antimicrobial activity of metal-based nanoparticles: a mini-review

The resistance of pathogenic microorganisms to antibiotics is one of the main problems of world health. Of particular concern are multidrug-resistant (MDR) bacteria. Infections caused by these microorganisms affect the appearance of acute or chronic diseases. In this regard, modern technologies, such as nanomaterials (NMs), especially promising nanoparticles (NPs), can possess antimicrobial properties or improve the effectiveness and delivery of known antibiotics. Their diversity and characteristics, combined with surface functionalization, enable multivalent interactions with microbial biomolecules. This article presents an overview of the most current research on replacing antibiotics with NPs, including the prospects and risks involved.

Eco-friendly green synthesis of AgNPs from Elaeocarpus serratus fruit extract: potential to antibacterial, antioxidant, cytotoxic effects of colon cancerous cells (HT-29) and its toxicity assessments of marine microcrustacean Artemia nauplii

BACKGROUND

The present work demonstrated the green synthesis and characterization of silver nanoparticles (AgNPs) utilizing Elaeocarpus serratus fruit extract. The study examined the effectiveness of phytocompounds in fruit extract in reducing Ag+ to Ag° ions.

METHODS

The water-soluble biobased substance production from silver ions to AgNPs in 45 min at room temperature. Surface plasmon resonance (SPR) peak was seen in the UV-visible absorption spectrum of the biologically altered response mixture. Examination with X-ray diffraction (XRD) showed that AgNPs are strong and have a face-centered cubic shape. Scanning electron microscope (SEM) investigation proved the production of AgNPs in a cuboidal shape.

RESULTS

The AgNPs demonstrated remarkable antibacterial activity and a potent capacity to neutralize DPPH (2,2-Diphenyl-1-picrylhydrazyl) radicals. The highest growth inhibition was found for E. serratus against S. dysenteriae (18.5 ± 1.0 mm) and S. aureus (18 ± 1.2 mm). These nanoparticles exhibited robust antiradical efficacy even at low concentrations. The AgNPs additionally exhibited cytotoxic effects on (HT-29) human colon adenocarcinoma cancer cells. The MTT assay (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) indicated an inhibitory concentration (IC50) value of 49.1 ± 2.33 µg/mL for AgNPs, contrasting with the untreated cells of the negative control. The biotoxicity assessment using A. salina displayed mortality rates ranging from 8 to 69.33%, attributable to the E. serratus synthesized AgNPs.

CONCLUSIONS

In our results concluded that simply first-hand information on that E. serattus fruit extract synthesized AgNPs were efficiently synthesized without the addition of any hazardous substances, and that they may be a strong antibacterial, antioxidant, and potential cytotoxic effects for the treatment of colon carcinoma cell lines.

Peptide Stereochemistry Effects from pKa-Shift to Gold Nanoparticle Templating in a Supramolecular Hydrogel

The divergent supramolecular behavior of a series of tripeptide stereoisomers was elucidated through spectroscopic, microscopic, crystallographic, and computational techniques. Only two epimers were able to effectively self-organize into amphipathic structures, leading to supramolecular hydrogels or crystals, respectively. Despite the similarity between the two peptides' turn conformations, stereoconfiguration led to different abilities to engage in intramolecular hydrogen bonding. Self-assembly further shifted the pKa value of the C-terminal side chain. As a result, across the pH range 4-6, only one epimer predominated sufficiently as a zwitterion to reach the critical molar fraction, allowing gelation. By contrast, the differing pKa values and higher dipole moment of the other epimer favored crystallization. The four stereoisomers were further tested for gold nanoparticle (AuNP) formation, with the supramolecular hydrogel being the key to control and stabilize AuNPs, yielding a nanocomposite that catalyzed the photodegradation of a dye. Importantly, the AuNP formation occurred without the use of reductants other than the peptide, and the redox chemistry was investigated by LC-MS, NMR, and infrared scattering-type near field optical microscopy (IR s-SNOM). This study provides important insights for the rational design of simple peptides as minimalistic and green building blocks for functional nanocomposites.