Over the past few decades, metal nanoparticles less than 100 nm in diameter have made a substantial impact across diverse biomedical applications, such as diagnostic and medical devices, for personalized healthcare practice. In particular, silver nanoparticles (AgNPs) have great potential in a broad range of applications as antimicrobial agents, biomedical device coatings, drug-delivery carriers, imaging probes, and diagnostic and optoelectronic platforms, since they have discrete physical and optical properties and biochemical functionality tailored by diverse size- and shape-controlled AgNPs. In this review, we aimed to present major routes of synthesis of AgNPs, including physical, chemical, and biological synthesis processes, along with discrete physiochemical characteristics of AgNPs. We also discuss the underlying intricate molecular mechanisms behind their plasmonic properties on mono/bimetallic structures, potential cellular/microbial cytotoxicity, and optoelectronic property. Lastly, we conclude this review with a summary of current applications of AgNPs in nanoscience and nanomedicine and discuss their future perspectives in these areas.

https://www.mdpi.com/1422-0067/20/4/865/pdf

Silver Nanoparticles: Synthesis and Application for Nanomedicine

Characterization of silver nanoparticles synthesized using Urtica dioica Linn. leaves and their synergistic effects with antibiotics

Ongoing advances in nanotechnology research have established a variety of methods to synthesize nanoparticles (NPs) from a diverse range of materials, including metals, semiconductors, ceramics, metal oxides, polymers, etc. Depending upon their origin and synthesis methods, NPs possess unique physicochemical, structural and morphological characteristics, which are important in a wide variety of applications concomitant to electronic, optoelectronic, optical, electrochemical, environment and biomedical fields. This review provides a comprehensive overview on various physical, chemical and bio-assisted methods largely employed to synthesize and fabricate NPs of varying size, surface characteristics, functionalities and physicochemical behavior. The key applications of nanoparticles have also been discussed.

Methods and strategies for the synthesis of diverse nanoparticles and their applications: a comprehensive overview

Enzymatic biodiesel: Challenges and opportunities

The role of activated charcoal in plant tissue culture.

Plantlets were regenerated from hypocotyl callus of Morus alba cv. MR2. Calli were established from hypocotyl segments on Murashige and Skoog (MS) medium supplemented with indoleacetic acid (0.5 mg/1) and benzyladenine (BA) (0.5 mg/1). They were transferred to MS medium with different concentrations of naphthaleneacetic acid NAA and BA for four weeks. Adventitious shoot buds were observed by transferring callus onto fresh Linsmaier and Skoog (LS) medium containing NAA (0.5 mg/1) and BA (0.75 mg/1). Shoots produced in vitro were rooted on MS medium with indolebutyric acid (0.75 mg/1).

Regeneration of plantlets from hypocotyl derived callus of morus alba

Les cultures de cals sont entreprises a partir de l'hypocotyle, du petiole, des feuilles jeunes et mures et des segments de tiges du Morus alba sur le milieu MS additionne de diverses auxines comme 2,4-D, NAA et IAA combines avec BAP. La frequence plus elevee de cals est obtenue sur le milieu IAA et BAP. Les bourgeons de pousses adventives sont induits a partir du cal hypocotyle, mais aucune reaction n'a ete observee a partir de cals d'autres sources d'explants. La frequence maximale de developpement des bourgeons de pousses adventives est observee dans une periode allant de quatre a cinq semaines sur le milieu MS additionne de NAA (0,50mg/l) et de BAP (0, 75mg/l). Les plantules regenerees sont ainsi sous-cultivees sur le milieu d'induction des racines avec IBA et plus tard renforcees.

Adventitious shoot formation and plant regeneration from callus cultures of mulberry (Morus alba L.)

Agrobacterium-mediated transformation in Cucumis sativus via direct organogenesis.

Withania somnifera is an important medicinal plant and used to cure many diseases. Direct regeneration method was standardized for the nodal explants of W. somnifera. In this method, the maximum of 42.4 ± 2.68 shoots produced per explant was achieved at 1.5 mg l−1 BAP with 0.3 mg l−1 IAA in the second subculture. Transformation was performed in the nodal explants of W. somnifera via direct regeneration using Agrobacterium tumefaciens strain EHA105 that harbored a binary vector pGA492, which carrying kanamycin resistant (nptII), phosphinothricin resistant (bar) and an intron containing β-glucuronidase (gus-intron) genes. The sensitivity of nodal explants to kanamycin (300 mg l−1) was determined for the selection of transformed plants. Transformation was confirmed by histochemical β-glucuronidase (GUS) assay and amplification of the nptII gene by polymerase chain reaction (PCR). PCR and southern blot analyses confirmed the integration of nptII gene in the genome of W. somnifera and the transformation frequency of 3.16 % has been achieved. This is the first report on the genetic transformation of W. somnifera using nodal explants, which may aid in the transformation of any other character gene for improving therapeutic value.

Agrobacterium -mediated genetic transformation of Withania somnifera using nodal explants

Several reciprocal cross pollinations were made between Solanum nigrum (2n=72) and S. retroflexum (2n=48); crosses were successful when the higher chromo-somal form was used as female parents; the cause for failure of its reciprocal crosses was discussed.Cytomorphological features of the species and their F1 hybrid were studied. The hybrid was pentaploid (2n=60). Its breakdown of meiosis and high pollen sterility seem to be primarily due to chromosomal cause. From the occurrence of as many as 24 bivalents and 12 univalents in few pollen mother cells of the hybrids, it is suspected that S. retroflexum or one of its close relatives has participated in origin of S. nigrum.

Andy Ganapathi

Papers

Regeneration of plantlets from hypocotyl derived callus of morus alba

Adventitious shoot formation and plant regeneration from callus cultures of mulberry (Morus alba L.)

Agrobacterium-mediated transformation in Cucumis sativus via direct organogenesis.

Agrobacterium -mediated genetic transformation of Withania somnifera using nodal explants

The crossability and genetic relationship between Solanum retroflexum Dun. and S. nigrum L.