Surendra Nimesh

Effect of size on biological properties of nanoparticles employed in gene delivery

Context: The size of nanoparticles plays a pivotal role in determining the gene delivery efficiency. Objective: A focus on the studies done to investigate the effect of nanoparticles size on biological aspects of gene delivery. Methods: A through literature survey has been done regarding studies done to investigate the effect of nanoparticles size on uptake, transfection efficiency and biodistribution has been cited in the present review. Results and conclusion: The gene delivery efficacy may depend on conjugation of several factors such as the chemical structure of polymers, cell type, and nanoparticle size, composition and interaction with cells.

Advances in preparation and characterization of chitosan nanoparticles for therapeutics

Context: Polymers have been largely explored for the preparation of nanoparticles due to ease of preparation and modification, large gene/drug loading capacity, and biocompatibility. Various methods have been adapted for the preparation and characterization of chitosan nanoparticles. Objective: Focus on the different methods of preparation and characterization of chitosan nanoparticles. Methods: Detailed literature survey has been done for the studies reporting various methods of preparation and characterization of chitosan nanoparticles. Results and conclusion: Published database suggests of several methods which have been developed for the preparation and characterization of chitosan nanoparticles as per the application.

Antibacterial and photocatalytic degradation efficacy of silver nanoparticles biosynthesized using Cordia dichotoma leaves extract

The present study focuses on the biosynthesis of silver nanoparticles (AgNPs) along with its antibacterial and photocatalytic activity. The AgNPs were synthesized using Cordia dichotoma leaf extract and were characterized using UV-vis spectroscopy to determine the formation of AgNPs. FTIR was done to discern biomolecules responsible for reduction and capping of the synthesized nanoparticles. Further, DLS technique was performed to examine its hydrodynamic diameter, followed by SEM, TEM and XRD to determine its size, morphology and crystalline structure. Later, these AgNPs were studied for their potential role in antibacterial activity and photocatalytic degradation of azo dyes such as methylene blue and Congo red.

Antibacterial efficacy of silver nanoparticles synthesized employing Terminalia arjuna bark extract

Abstract In the present investigation, we have explored simple, robust, inexpensive, and eco-friendly method for the synthesis of silver nanoparticles (AgNPs) using Terminalia arjuna bark extract (TA-AgNPs). Various parameters dictating the biosynthesis of TA-AgNPs such as time and temperature of reaction, concentration of AgNO3, and T. arjuna extract amount were investigated. Characterization of TA-AgNPs was done via UV-vis spectroscopy along with FT-IR, XRD, SEM and dynamic light scattering. The antimicrobial activity of TA-AgNPs was investigated against Escherichia coli. Comparable zone of inhibition was exhibited by TA-AgNPs. This study suggests that TA-AgNPs possesses significant antibacterial properties.

RNA interference technology with emphasis on delivery vehicles—prospects and limitations

Context: RNA interference (RNAi)-based therapeutics rely upon safe and efficient delivery of small interfering RNA (siRNA) molecules. Objective: This review explores various dimensions of RNAi with emphasis on the development of nanoparticle-based delivery vectors for safe and efficient siRNA delivery. Methods: An exhaustive database search has been done regarding studies done to investigate the potential of siRNA delivery employing nanoparticles has been cited in the present review. Results and conclusion: With the current challenges, there is a need for collaborative work allowing for the successful development of nanoparticle/siRNA complexes as health-promoting biotherapeutics.

Green synthesis of silver nanoparticles using Prosopis juliflora bark extract: reaction optimization, antimicrobial and catalytic activities.

Abstract In the present study, silver nanoparticles (PJB-AgNPs) have been biosynthesized employing Prosopis juliflora bark extract. The biosynthesis of silver nanoparticles was monitored on UV-vis spectrophotometer. The size, charge and polydispersity index (PDI) of PJB-AgNPs were determined using dynamic light scattering (DLS). Different parameters dictating the size of PJB-AgNPs were explored. Nanoparticles biosynthesis optimization studies suggested efficient synthesis of highly dispersed PJB-AgNPs at 25 °C when 9.5 ml of 1 mM AgNO3 was reduced with 0.5 ml of bark extract for 40 min. Characterization of PJB-AgNPs by SEM showed spherical-shaped nanoparticles with a size range ∼10–50 nm along with a hydrodynamic diameter of ∼55 nm as evaluated by DLS. Further, characterizations were done by FTIR and EDS to evaluate the functional groups and purity of PJB-AgNPs. The antibacterial potential of PJB-AgNPs was tested against E. coli and P. aeruginosa. The PJB-AgNPs remarkably exhibited anticancer activity against A549 cell line as evidenced by Alamar blue assay. The dye degradation activity was also evaluated against 4-nitrophenol that has carcinogenic effect. The results thus obtained suggest application of PJB-AgNPs as antimicrobial, anticancer and catalytic agents.

Hypochlorite-promoted inhibition of photo-induced electron transfer in phenothiazine–borondipyrromethene donor–acceptor dyad: a cost-effective and metal-free “turn-on” fluorescent chemosensor for hypochlorite

A phenothiazine (PTZ)–borondipyrromethene (BODIPY) based electron donor–acceptor dyad, 1, was designed and used for the sensitive and selective detection of hypochlorite. Upon excitation of the BODIPY moiety, the fluorescence of 1 was observed to be quenched (∼90%) due to photo-induced electron transfer from PTZ to 1BODIPY*. However, upon the addition of incremental amounts of NaOCl, the fluorescence of 1 was enhanced, indicating inhibition of the reductive PET process from PTZ to BODIPY, which was quickly restored upon treatment with H2S, indicating the reversibility of the probe for the continuous detection of hypochlorite. Parallel time-resolved fluorescence studies showed a decrease in the lifetime of the BODIPY moiety compared to the pristine BODIPY, and upon the addition of NaOCl, the lifetime of the BODIPY moiety (0.7 ns) in 1 was observed to be recovered highlighting the real-time applications of the probe in sensing NaOCl. Steady-state fluorescence experiments at varied pH have suggested that 1 can detect NaOCl in the pH range of 7–8, similar to physiological conditions, and at a pH of 7.6, 1 displayed high selectivity for hypochlorite over other reactive oxygen species. To understand the chemical and photophysical mechanisms involved in the fluorescence “turn-on” event, 1 was treated with NaOCl and subjected to ESI-MS analysis. Mass spectrometry showed the formation of oxidized products, sulfoxide and sulfone, and the density functional theory studies confirmed that the formation of these products was responsible for the inhibition of the reductive PET process from the PTZ group to the 1BODIPY* moiety. Also, 1 exhibited enhanced fluorescence upon treatment with commercially available sodium hypochlorite disinfectants, indicating the applications of the probe to real samples. Cytotoxicity studies performed on HEK 293 cells suggested that, up to a 5 μM concentration of 1, the cell viability is above 80%, implicating the applications of the probe for biological samples.

Degradation of anthropogenic pollutant and organic dyes by biosynthesized silver nano-catalyst from Cicer arietinum leaves

The work represents the potent catalytic activity of silver nanoparticles synthesized from Cicer arietinum (chickpea) leaf extract (CAL-AgNPs). Here, silver nano-catalysts were used against the anthropogenic pollutants mainly involving nitro-amines and azo dyes. These pollutants are extremely harmful to our environment and causes severe health issues. The CAL-AgNPs have the potential to degrade harmful toxins and their by-products, thereby decreasing the pollutants from the environment. The green synthesis of nano-catalyst includes a simple, cost effective and eco-friendly method using the leaf extract from the plant. A systematic study was conducted, including synthesis, optimization and characterization of the silver particles. The AgNPs were further assessed through DLS and TEM for size and morphological evaluation. The obtained particles have shown spherical morphology with the size range of 88.8nm. Further, FTIR were performed for compositional and functional group analysis of the particles. The antibacterial efficiency was also evaluated against E. coli and P. aeruginosa. For their catalytic evaluation, CAL-AgNPs were assessed for 4-nitrophenol, methylene blue and congo red. The results obtained through catalytic evaluation suggested that the CAL-AgNPs could be helpful to surmount the environmental pollution in a very effective manner.

Hypochlorite-Mediated Modulation of Photoinduced Electron Transfer in a Phenothiazine-Boron dipyrromethene Electron Donor-Acceptor Dyad: A Highly Water Soluble “Turn-On” Fluorescent Probe for Hypochlorite

A highly water-soluble phenothiazine (PTZ)-boron dipyrromethene (BODIPY)-based electron donor-acceptor dyad (WS-Probe), which contains BODIPY as the signaling antennae and PTZ as the OCl- reactive group, was designed and used as a fluorescent chemosensor for the detection of OCl- . Upon addition of incremental amounts of NaOCl, the quenched fluorescence of WS-Probe was enhanced drastically, which indicated the inhibition of reductive photoinduced electron transfer (PET) from PTZ to 1 BODIPY*; the detection limit was calculated to be 26.7 nm. Selectivity studies with various reactive oxygen species, cations, and anions revealed that WS-Probe was able to detect OCl- selectively. Steady-state fluorescence studies performed at varied pH suggested that WS-Probe can detect NaOCl and exhibits maximum fluorescence in the pH range of 7 to 8, similar to physiological conditions. ESI-MS analysis and 1 H NMR spectroscopy titrations showed the formation of sulfoxide as the major oxidized product upon addition of hypochlorite. More interestingly, when WS-Probe was treated with real water samples, the fluorescence response was clearly visible with tap water and disinfectant, which indicated the presence of OCl- in these samples. The in vitro cell viability assay performed with human embryonic kidney 293 (HEK 293) cells suggested that WS-probe is non-toxic up to 10 μm and implicates the use of the probe for biological applications.

Polymeric nanocarriers for site-specific gene therapy

Abstract Rapid progress in nanotechnology toward the development of delivery systems has revolutionized the strategies of gene therapy. Design and development of efficient polymeric nanoparticles has become a prerequisite for successful gene delivery. Their unique properties such as biodegradability, nontoxicity and biocompatibility are gaining significant interest. However, site-specific targeting and intracellular delivery encounters several challenges toward the success of gene therapy. To address this issue, interesting manipulations are being executed, attributed to the tailorability of nanoparticles; to make them promising delivery vectors. In this chapter, we have explored the strategies and advances made toward the development of polymeric nanocarriers in order to achieve site-specific gene delivery.