Green and facile fabrication of silver nanoparticles using Konjac Glucomannan by photocatalytic strategy

Mapping the Progress in Surface Plasmon Resonance Analysis of Phytogenic Silver Nanoparticles with Colorimetric Sensing Applications

Nanotechnology is gaining enormous attention as the most dynamic research area in science and technology. It involves the synthesis and applications of nanomaterials in diverse fields including medical, agriculture, textiles, food technology, cosmetics, aerospace, electronics, etc. Silver nanoparticles (AgNPs) have been extensively used in such applications due to their excellent physicochemical, antibacterial, and biological properties. The use of plant extract as a biological reactor is one of the most promising solutions for the synthesis of AgNPs because this process overcomes the drawbacks of physical and chemical methods. This review article summarizes the plant-mediated synthesis process, the probable reaction mechanism, and the colorimetric sensing applications of AgNPs. Plant-mediated synthesis parameters largely affect the surface plasmon resonance (SPR) characteristic due to the changes in the size and shape of AgNPs. These changes in the size and shape of plant-mediated AgNPs are elaborately discussed here by analyzing the surface plasmon resonance characteristics. Furthermore, this article also highlights the promising applications of plant-mediated AgNPs in sensing applications regarding the detection of mercury, hydrogen peroxide, lead, and glucose. Finally, it describes the future perspective of plant-mediated AgNPs for the development of green chemistry.

Synthesis of cationic β-cyclodextrin functionalized silver nanoparticles and their drug-loading applications

Silver nanoparticles have attracted great attention owing to their distinct physicochemical properties, which inspire the development of their synthesis methodology and their potential biomedical applications. In this study, a novel cationic β-cyclodextrin (C-β-CD) containing a quaternary ammonium group and amino group was applied as a reducing agent as well as a stabilizing agent to prepare C-β-CD modified silver nanoparticles (CβCD-AgNPs). Besides, based on the inclusion complexation between drug molecules and C-β-CD, the application of CβCD-AgNPs in drug loading was explored by the inclusion interaction with thymol. The formation of AgNPs was confirmed by ultraviolet-visible spectroscopy (UV-vis) and X-ray diffraction spectroscopy (XRD). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed the prepared CβCD-AgNPs were well dispersed with particle sizes between 3-13 nm, and the zeta potential measurement result suggested that the C-β-CD played a role in preventing their aggregation in solution. ¹H Nuclear magnetic resonance spectroscopy (¹H-NMR) and Fourier transform infrared spectroscopy (FT-IR) revealed the encapsulation and reduction of AgNPs by C-β-CD. The drug-loading action of CβCD-AgNPs was demonstrated by UV-vis and headspace solid-phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS), and the results of TEM images showed the size increase of nanoparticles after drug loading.

Synthesis of biocompatible Konjac glucomannan stabilized silver nanoparticles, with Asystasia gangetica phenolic extract for colorimetric detection of mercury (II) ion

Herein, the synthesis of a biocompatible silver nanoparticles (AgNPs), for colorimetric detection of toxic mercury (II) ion (Hg²⁺), is reported. Phenolic-rich fraction of Asystasia gangetica leaf was extracted and used as a reductant of silver salt, all within the hydrophilic konjac glucomannan (KgM) solution as stabilizer, at room temperature (RT). The bioactive components of Asystasia gangetica phenolic extract (AGPE), as elucidated with a (UHPLC-MS-QTOF-MS), revealed plethora of phenolic compounds, which can facilitate the reduction of silver salt at ambient conditions. Sparkling yellow colloidal solution of KgM-AgNPs was realized within 1 h, at RT, having a UV–vis maximum at 420 nm. KgM-AgNPs was characterized using UV–vis, Raman and (FTIR), TEM, SEM, EDS, XRD, TGA/DTG. TEM and FESEM images showed that KgM-AgNPs were spherical, with particle size distribution around 10–15 nm from TEM. The KgM-AgNPs biocompatibility was investigated on mouse L929 fibrobroblast and rat erythrocytes, without any harmful damages on the tested cells. In aqueous environment, KgM-AgNPs demonstrated good detection capacity toward Hg²⁺, in a Hg²⁺ concentration dependent fashion, within 3 min. Absorbance ratios (A₃₆₀/A₄₀₈) was linear with Hg²⁺ concentrations from 0.010–10.0 to 10.0–60.0 µM, with an estimated (LOD) of 3.25 nM. The probe was applied in lake water sample, with satisfactory accuracy.

The impact of silver nanoparticles phytosynthesized with Viburnum opulus L. extract on the ultrastrastructure and cell death in the testis of offspring rats

AIM

To investigate the effects of prenatal exposure to AgNPs obtained by green synthesis with Viburnum opulus L. extract on the testis in male offspring rats.

MATERIAL AND METHODS

Two different doses of AgNPs (0.8 and 1.5 mg/kg b.w.) and vehicle (PBS) were administered to Wistar female rats on days 3-14 of gestation. At 6 weeks after birth, the ultrastructural changes in correlation with the amount of silver as well as the parameters of oxidative stress, inflammation and cell death mechanisms in the testis of male offspring were evaluated.

RESULTS

AgNPs administered during pregnancy crossed the placental and testicular barriers and induced oxidative stress, DNA damage and autophagy as mechanism of cell toxicity. The markers of inflammation and apoptosis decreased after AgNPs exposure while the NFkB activation increased. TEM examination revealed important ultrastructural changes of Sertoli cells, numerous vacuoles and cytoplasmic changes suggestive of the cell's evolution towards necrosis.

CONCLUSION

Phytoreduced silver nanoparticles with polyphenols from Viburnum opulus L. fruit extract, administered during the embryological development of the male gonad, have testicular toxic effects in offspring even at 6 weeks after birth.