Dynamic Light Scattering Analysis Research Articles

Multimodal Theranostic Nanoparticles for Necrosis Targeting, Fluorescence/SPECT Imaging, and Radiotherapy of Residual Tumors after Hepatocellular Carcinoma Ablation.

Thermal ablation has been commonly used as an effective treatment for hepatocellular carcinoma; however, peri-necrotic tumor residues after ablation play a significant role in tumor recurrence and poor prognosis. Therefore, developing agents that can effectively target and eliminate residual tumors is critically needed. Necrosis targeting strategies have potential implications for evaluating tumor necrosis areas and treating the surrounding residual tumors. To address this issue, we have developed a biodegradable nanoparticle with necrosis avidity that is compatible with fluorescence imaging, single photon emission computed tomography (SPECT) imaging, and necrosis targeted radiotherapy. The nanoparticles were synthesized using iodine-131-labeled hypericin (131I-Hyp) as the core and amphiphilic copolymer poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-PCL) as the shell. The developed nanoparticle, PNP@(131I-Hyp), has a uniform spherical morphology with a size of 33.07 ± 3.94 and 45.93 ± 0.58 nm determined by cryogenic transmission electron microscopy (cryo-TEM) and dynamic light-scattering analysis (polydispersity index = 0.19 ± 0.01), respectively, and having a good stability and blood compatibility in vitro. In mouse subcutaneous ablated-residual tumor models, fluorescence and SPECT imaging demonstrated that PNP@(131I-Hyp) prominently accumulated in the tumor and was retained for as long as 168 h following intravenous injection. Moreover, ex vivo analyses showed that PNP@(131I-Hyp) mainly gathered in the necrotic zones of subcutaneous tumors and inhibited residual tumors by radiotherapy. In addition, histological examination of harvested organs and hematological analysis demonstrated that intravenous injection of 5 mCi/kg nanoparticles caused no gross abnormalities. This multifunctional nanoparticle, therefore, has necrosis imaging and targeted therapeutic effects on residual tumors after thermal ablation of hepatocellular carcinoma, showing potential for clinical application.

Adjuvant therapy with topical silymarin nanomicelles attenuates skin and hair depigmentation in a C57/BL6 mouse model of vitiligo

Nanomedicine holds great promise for delivering drugs to the skin. In this study, we explored the use of silymarin, a natural extract from Silybum marianum seeds, encapsulated in a micellar structure for topical treatment of vitiligo. The nanomicelles were characterized using dynamic light scattering (DLS). A C57/BL6 mouse model with vitiligo was utilized, and the depigmented skin area was topically treated with either silymarin nanomicelles or clobetasol for four consecutive weeks. Skin samples were collected for histopathological analysis and gene expression PCR analysis, while liver tissues were assessed for lipid peroxidation. DLS analysis revealed that more than 90% of the nanomicelles had a diameter below 30 nm and exhibited a narrow distribution. The in vivo study demonstrated that the nanomicellar form of silymarin was highly effective in suppressing vitiligo compared to clobetasol. Histopathological investigations indicated significant activation of melanocytes and reduced inflammation following treatment with silymarin nanomicelles. Moreover, lipid peroxidation analysis confirmed the antioxidant role of silymarin nanomicelles in scavenging reactive oxygen species. The downregulation of MITF, TRP1, and TRP2 expression following silymarin nanomicelle therapy was also found to be significant. Overall, the study demonstrated significant improvement of the depigmented skin patches, reduced skin inflammation, and downregulation of key genes involved in vitiligo, suggesting that silymarin nanomicelles hold promise as a viable therapeutic option for treating depigmented skin.

Synergistic effects of nano curcumin mediated photodynamic inactivation and nano-silver@colistin against Pseudomonas aeruginosa biofilms

BackgroundPatients with burn injuries colonized by multidrug-resistant Pseudomonas aeruginosa face increased mortality risk. The efficacy of colistin, a last-resort treatment, is declining as resistance levels rise. P. aeruginosa's robust biofilm exacerbates antibiotic resistance. Photodynamic Inactivation (PDI) shows promise in fighting biofilm. Materials and methodsNano curcumin (nCur) particles were synthesized, and their chemical characteristics were determined using zeta potential (ZP), dynamic light scattering analysis (DLS), energy-dispersive X-ray (EDX) analysis, and fourier transform infrared (FTIR). We conducted an MTT assay to assess the cytotoxicity of nCur-mediated PDI in combination with nanosilver colistin. The fractional biofilm inhibitory concentration (FBIC) of two P. aeruginosa clinical isolates and P. aeruginosa ATCC 27853 during nCur-mediated PDI@AgNPs@CL was determined using a 3-dimensional (3-D) checkerboard assay. To study the effect of nCur-mediated PDI@AgNPs@CL on lasI, lasR, rhlI, rhlR, pelA, and pslA gene expression, Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was conducted at each isolate's FBIC. The impact of treatments was also investigated using scanning electron microscopy (SEM). ResultsThe ZP and mean DLS values of the nCur were 10.3 mV and 402.6 ± 24.6 nm, respectively. The distinct functional groups of nCur corresponded with the peaks of FTIR absorption. Moreover, the EDX analysis showed the ratios of different metals in nCur. Cell viability percentages of nCur-mediated PDI@AgNPs@CL at FBIC concentrations of clinical isolates Nos. 30, 354, and P. aeruginosa ATCC 27853 were 91.36 %, 83.20 %, and 92.48 %, respectively. nCur-mediated PDI@AgNPs@CL treatment showed synergistic effects in clinical isolates and P. aeruginosa ATCC 27853 in a 3-D checkerboard assay. All six of the investigated genes showed down-regulation after nCur-mediated PDI@AgNPs@CL treatment. The most suppressed gene during nCur-mediated PDI@AgNPs@CL treatment was the rhlR gene (-11.9-fold) of P. aeruginosa ATCC 27853. The SEM micrographs further proved the connecting cement reduction and biofilm mass mitigation following nCur-mediated PDI@AgNPs@CL treatments. ConclusionsThe combined effect of nCur-mediated PDI and AgNPs@CL synergistically reduce the formation of biofilm in P. aeruginosa. This may be attributable to the suppression of the genes responsible for regulating the production of biofilms.

Nanoparticle Size Distribution and Stability Assessment Using Asymmetric-Flow Field-Flow Fractionation.

Nanomaterials are inherently polydisperse. Traditional techniques, such as the widely used batch-mode dynamic light-scattering (DLS) analysis, are not ideal nor thoroughly descriptive enough to define the full complexity of these materials. Asymmetric-flow field-flow fractionation (AF4) with various in-line detectors, such as ultraviolet-visible (UV-vis), multi-angle light scattering (MALS), refractive index (RI), and DLS, is an alternative technique that can provide flow-mode analysis of not only size distribution but also shape, drug release/stability, and protein binding.

Correlation between the size of released titanium particles and changes in the surface of dental implants during insertion into bone blocks: an in vitro study.

This study investigated the size and amount of titanium particles immediately released following dental implant insertion into bovine bone blocks and aimed to correlate them with the surface roughness of the implants. Twelve bone blocks were prepared from bovine mandibles. Six tapered (group A) and 6 cylindrical (group B) dental implants were inserted into the bone blocks under water irrigation, following the standard drilling protocol. After insertion, the implants were immediately removed from the bone. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and atomic force microscopy were performed to investigate the released titanium particles and implant surface roughness, respectively. The amount of titanium ions in the irrigation water was measured using inductively coupled plasma mass spectrometry. Dynamic light scattering (DLS) was used to determine the size range of the released titanium particles. The percentages of titanium content on the surface of implants decreased in both groups after implantation into bone blocks. SEM-EDX analysis confirmed the presence of titanium particles embedded in the implanted bone bed. Group B implants showed significantly higher concentrations of titanium ions in the collected water than group A implants (0.868 and 0.565 µg/L, respectively). Group A implants demonstrated high pre-implantation surface roughness, which led to a much greater decrease in post-implantation surface roughness than was observed for group B implants. DLS analysis showed that the titanium particles released from group A implants were within the nano-size range, whereas those released from group B implants were within the micro-size range. Dental implant placement leads to a decrease in implant surface roughness and the immediate release of titanium particles into the peri-implant bone. Variations in the size range and amount of released particles were correlated with implant surface roughness. This finding has clinical implications and warrants additional in vivo studies.

Assessing Lipid Nanoparticle Protein Corona Formation and Cytocompatibility

Lipid nanoparticles(LNPs) represent an emerging new modality for mRNA delivery. Following administration and interaction with blood constituents, LNPs form a corona complex consisting of proteins adsorbed on the surface altering their stability, biological identity, and fate. Cytocompatibility of the LNPs is an important factor when considering their safety efficacy in delivering the encapsulated drug dose, lipid choice and the specific target cells. The aim of this study was to investigate the changes in LNP physical parameters in physiologically-relevant media. Key attributes such as particle size, polydispersity index and zeta-potential were measured using Dynamic Light Scattering (DLS) and Nanoparticle Tracking Analysis (NTA). Cytocompatibility was assessed via CellTiter-Glo® assay. Following 24-hour incubation of LNPs with Bovine Serum Albumin (BSA), the LNP z-average increased from 92.4 (± 49.0) nm to 131.4 (± 64.9) nm indicating interaction between LNPs and BSA. A decrease in percentage cell viability was demonstrated with increased lipid concentration for MCF-7 and A549 cell lines. This work shows changes in LNP physicochemical properties in the presence of protein and biologically relevant conditions consistent with protein surface adsorption. The cytocompatibility of LNPs can be associated with the type of lipids used in the synthesis of LNPs.

Evaluation of biological activities of silver nanoparticles (AgNPs) synthesized by green nanotechnology from birch (Betula spp.) branches extract

Green synthesis of silver nanoparticles (AgNPs) provide superiority due to their usage of various biological applications. The aim of this study is synthesizing the silver nanoparticles by using Birch (Betula spp.) branches extract with an ecofriendly, cost-effective, simple, and cheap green method. Even Betula is wide-spread tree with rich in phenolic compounds, data on the use of Betula branches is limited. Within this scope, this study is the first for using Betula branche extracts which take part as reducing and capping agent to synthesize the silver nanoparticles to evaluate the antimicrobial activity and antiproliferative efficiency. The biosynthesized AgNPs were characterized by various characterization methods such as UV−visible spectroscopy, dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The characterization analysis has revealed the phenolic compounds of Betula extract acted as reducing and capping agent for formation of AgNPs.
 The synthesized selected AgNPs were exhibited spherical shape with 103.2 ± 5.2 and 69.2 ±12.7 nm according to DLS and SEM analysis, respectively. Also, the biological activity of biosynthesized AgNPs were evaluated by antimicrobial and antiproliferative tests on selected microorganisms and cell line, respectively. The IC50 values of B3-4 AgNPs was determined as 64.27 µg/mL on HT29 colorectal cancer cells. And also, the antimicrobial activity results of AgNPs have revealed the dose-dependent inhibition for all studied test microorganisms.
 In conclusion, this study evidently suggests the use of silver nanoparticles biosynthesized from Betula branches extract as a potential agent for antimicrobial and anticancer studies.

Optimizing the Synthesis of Folic Acid Conjugated Silver Nanoparticles by Box-Behnken Design to Target Breast Cancer Cells

In this study, the synthesis of folic acid conjugated silver nanoparticles (FA&AgNPs) was optimized. FA&AgNPs were synthesized by reduction of silver nitrate with folic acid, which is widely used to target folate receptors in cancer cells. Five independent variables (stirring speed, AgNO3 concentration, folic acid concentration, AgNO3 volume/folic acid volume, and temperature) that were effective on silver nanoparticle synthesis were determined. Based on the independent variables, an experimental plan consisting of 46 experiments was created using the Box-Behnken design (BBD). Nanoparticle formation, physical color change, UV-Vis absorption spectroscopy, Dynamic Light Scattering (DLS) analysis, and Fourier Transform Infrared (FTIR) analysis were evaluated. The mean particle size and zeta potential of FA&AgNPs produced under optimized conditions were measured as 207±4.3 nm and -51.6 mV±2.5, respectively. Cytotoxicity tests were performed to evaluate the anticancer activity of FA&AgNPs in breast cancer cell lines. The IC50 values for MDA-MB-231 breast cancer cells at 24 hours and 48 hours were 20.0 µg/mL and 16.9 µg/mL, respectively, and 26.3 µg/mL and 31.5 µg/mL for MCF-7 cells. The findings indicated that FA&AgNPs have the potential to be an effective anticancer agent in breast cancer cells.

Eco-friendly synthesized manganese dioxide nanoparticles using Tridax procumbens as potent antimicrobial and dye degrading agent

Manganese dioxide nanoparticles (MnO2 NPs) were synthesized via a typical green synthesis method involving Tridax procumbens (TP) leaf extract extraction and utilization. The as-prepared material was further characterized using various physio-chemical methods to comprehend its structural, morphological, and optical properties. Powder X-ray diffraction (PXRD) reveals a tetragonal system with a space group of I 41/a m d, clearly indicating the presence of phytochemicals (impurity peaks at 25.46° and 54.92° diffraction angles). The calculated crystalline size of the sample was found to be 43 nm. Field Emission Scanning Electron Microscope (FESEM) results confirm the precursors of the as-prepared sample, also revealing the agglomerated structure. Furthermore, deeper morphology and crystallinity of the as-prepared MnO2 NPs have been studied through High-Resolution Transmission Electron Microscope (HR-TEM) images, which affirms the information about calculated d-spacing value (0.328 nm) and confirming crystallinity through Selected Area Electron Diffraction (SAED) image. Absorption studies were conducted on as-prepared samples, which show a characteristic band at 257 nm, affirming the formation of MnO2 NPs. The same was utilized to evaluate the band gap energy (4.46 eV) through the Kubelka-Munk function. To further confirm the calculated particle size and stability of the as-prepared MnO2 NPs, Dynamic Light Scattering (DLS) analysis was conducted, and the results revealed that the particles’ size was 58.72 nm. The prepared samples were subjected to study antimicrobial studies against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacterial species. The inhibition zone of the antibacterial disc soaked with as-prepared MnO2 NPs showed a significant increase compared to the TP leaf extract and commercially available MnO2 NPs. Also, the degradation of the Titan Yellow dye solution was conducted employing UV irradiation, and it was found that the maximum degradation percentage was attained after 120 min of irradiation. Furthermore, the pH effect on %degradation and reusability test were also conducted. The obtained results showed a pinnacle pH point of 4 where the degradation was maximum and found a decent decrement in %degradation after 4th usage. All the acquired results were utilized to study the degradation reaction kinetics, which was found that the present degradation holds good for both 0th and 1st order kinetic equations. Henceforth, the acquired results suggest that the green synthesized MnO2 NPs are potent candidates for antimicrobial and degrading activities.

Green synthesis of silver nanoparticles employing hamdard joshanda extract: putative antimicrobial potential against gram positive and gram negative bacteria.

The bio-mediated synthesis of nanoparticles offers a sustainable and eco-friendly approach. In the present study, silver nanoparticles (AgNPs) were synthesized using Joshanda extract, a commercially available herbal formulation derived from a traditional medicinal plant, as a reducing and stabilizing agent. The as-synthesized AgNPs were characterized using UV-Vis spectroscopy, dynamic light scattering (DLS), X-ray Diffraction (XRD) study, and Fourier-transform infrared (FTIR) analysis. UV-Vis spectroscopy exhibited a prominent absorption peak at 430nm, confirming the formation of AgNPs. DLS analysis revealed the size distribution of the nanoparticles, ranging from 80 to 100nm, and zeta potential measurements indicated a surface charge of -14.4mV. The XRD analysis provide evidence for the presence of a face-centered cubic structure within the silver nanoparticles. FTIR analysis further elucidated the interaction of bioactive compounds from the Joshanda extract with the AgNPs' surface. Strong peaks at 765-829cm-1 indicated C-Cl stretching vibrations of alkyl halides, while the stretching of alkenes C=C was observed at 1641cm-1. Moreover, the presence of alcohols and phenol (OH) groups was identified at 3448cm-1, suggesting their involvement in nanoparticle stabilization. The antimicrobial potential of the synthesized AgNPs was evaluated against both gram-negative Pseudomonas aeruginosa and gram-positive Streptococcus mutans using zone of inhibition assays. The AgNPs exhibited remarkable inhibitory effects against both types of bacteria. Additionally, AgNPs-treated groups demonstrated a significant increase in reactive oxygen species (ROS) levels, indicating potential of as-synthesized AgNPs in disruption of the target microbial membranes. Furthermore, the as-synthesized AgNPs exhibited notable anti-biofilm properties by effectively hindering the development of mature biofilms. This study highlights the efficient green synthesis of AgNPs using Joshanda extract and also provides insights into their physico-chemical properties of as-synthesized nanoparticles. The demonstrated antimicrobial activity against both gram-negative and gram-positive bacteria, along with biofilm inhibition potential, underscores the promising applications of the as-synthesized AgNPs in the field of biomedical and environmental sciences. The study bridges traditional knowledge with contemporary nanotechnology, offering a novel avenue for the development of eco-friendly antimicrobial agents.

Fabrication of Copper Nano/Honey Loaded Polymeric Composite with Microbial activity

Polymers are known as lead compounds for therapeutic drug development to treat a variety of conditions. Polymers have become an essential part of drug delivery systems because of their improved pharmacokinetic properties. Additionally, Copper is also recognized as a well-known antibacterial metal. In an in-vitro assay, solid copper surfaces killed 99.9% of microbes within 2hours of contact. Honey exhibits a broad-spectrum antibacterial activity against gram-positive and gram-negative bacteria. It also has anti-inflammatory and antioxidant activities. In this study, polyvinyl alcohol (PVA) and starch (St) are prepared by cross-linking with glutaraldehyde (GA) composite sheets and filled with pure honey and copper nanoparticles. The synthesized films are characterized by various methods such as X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). Chemical analysis is also carried out such as Swelling study and Expansion study. Copper nanoparticles are characterized by ultraviolet (UV)-visible spectroscopy and dynamic light scattering analysis (DLS). Along with this, Honey is characterized by ultraviolet (UV)-visible spectroscopy. Various network parameters were evaluated using the source data. Swelling parameters were also evaluated using a gelatin swelling assay. The antibacterial activity of PVA/St films loaded with honey and copper nanoparticles was tested against Escherichia coli bacteria (E. Coli bacteria).

Hybrid nanocarriers based on polyacrylic acid, polyvinyl pyrrolidone, and molybdenum disulfide for enhanced 5-fluorouracil delivery in lung cancer therapy

An innovative hydrogel nanocomposite, synthesized from a hybrid of PAA, PVP, and MoS2, represents a pioneering solution for pH-responsive drug delivery. This nanocomposite is specifically tailored for the controlled release of 5-Fluorouracil (5-FU), an anti-cancer agent. The infusion of MoS2 into the PAA-modified PVP hydrogel imparts a distinct feature, further enriched by the incorporation of Span 80 surfactant, culminating in the creation of stable niosomal microemulsions that enhance the retention of 5-FU. The incorporation of paraffin oil helps reduce the size of the microemulsions while maintaining their quasi-spherical shape. To characterize the microemulsions in this study, we employed FT-IR spectroscopy and X-ray diffraction (XRD) methods for our analysis. Additionally, Dynamic Light Scattering (DLS) analysis confirmed the presence of nanoparticles within the nanocarriers, with an average dimension of nearly 315 nm and a polydispersity index (PDI) of 0.27. These entities exhibit a spherical morphology, as revealed by SEM imaging. Zeta potential measurements highlight a negative surface charge of approximately –33.5 mV. Remarkably, we achieved significant drug loading and entrapment efficiencies, reaching 46 % and 87.25 %, respectively, surpassing those reported for other nanocarriers in previous studies. Cellular experiments conducted on A549 and L929 cell lines showcased the enhanced anticancer activity of 5-FU-loaded nanoparticles and assessed potential side effects.The results underscore the promising potential of the nanocarrier as a favorable strategy for delivering drugs in cancer treatment.

Phyto-assisted eco-friendly fabrication of haemocompatible vanadium nanoparticles using Azadirachta indica leaf extract inherent with antioxidant and anti-bacterial activity

In the present investigation, vanadium nanoparticles (VNPs) were synthesized through green process that entailed the use of Azadirachta indica leaf extract from sodium metavanadate. The characterization of VNPs involved a multitude of techniques, namely UV-Vis spectroscopy, Dynamic light scattering (DLS), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). Analytical studies, such as UV-Vis spectra, established the band gap of 2.5 eV, demonstrating the semi-conductive nature of VNPs. According to DLS analysis, nanoparticles (NPs) had an average size of 113 nm. The subsequent characterization techniques validated the rod-shaped and crystalline structure of the NPs. Following the effective synthesis of NPs, antioxidant studies determined their in vitro radicle quenching competence against superoxide, hydrogen peroxide, and DPPH radicles. The VNPs exhibited an outstanding antioxidant potential and displayed a prominent protective effect in chicken erythrocytes subjected to H2O2-induced oxidative stress. Furthermore, VNPs were evaluated for anti-bacterial efficacy against various bacterial species, including Klebsiella aerogenes, Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, and Lactobacillus acidophilus, showing zones of inhibition at low doses. Thus, VNPs from Azadirachta indica leaf extract could be utilized in medicine as a preventative measure against oxidative stress and bacterial disorders.

In vitro analyses of cerium oxide nanoparticles in degrading anthracene/fluorene and revealing the antibiofilm activity against bacteria and fungi

A sol-gel method was used to synthesize the cerium dioxide nanoparticles. The nanoparticles formed were then characterized with UV–visible spectrophotometry, Fourier Transform Infrared Spectrophotometer (FTIR), SEM-EDAX, XRD, and Dynamic Light Scattering (DLS). The UV–visible absorbance at 282 nm and characteristic peak at 600-4000 cm−1 provided insight into the formation of cerium dioxide nanoparticles using a chemical method. SEM analysis and EDAX analysis confirmed nanoparticle formation and elements within the nanoparticles based on their irregular morphology. The hydrodynamic size obtained from the DLS analysis was 178.4 nm and the polydispersity was 0.275 nm. Furthermore, XRD results confirmed the crystalline nature of cerium dioxide nanoparticles. Using batch adsorption as a method, the effect of concentration of Polycyclic Aromatic Hydrocarbons (PAH), adsorbent concentration, pH, and irradiation source was investigated. Under UV light conditions, 10 μg/mL cerium dioxide nanoparticle at pH 5 degraded 2 μg/mL of PAH (anthracene and fluorene). Consequently, the synthesized cerium dioxide nanoparticles were effective photocatalysts. For anthracene and fluorene, kinetic studies showed the degradation process followed pseudo-second-order kinetics and Freundlich isotherms. Cerium oxide also exhibited significant antimicrobial and antibiofilm activity against bacteria and fungi. As a result, the cerium dioxide nanoparticle has proved to be a highly effective photocatalytic tool for the degradation of PAHs and exhibits strong antimicrobial activity.

Microwave-Assisted Silanization of Magnetite Nanoparticles Pre-Synthesized by a 3D Microfluidic Platform.

Magnetite nanoparticles (Fe3O4 NPs) are among the most investigated nanomaterials, being recognized for their biocompatibility, versatility, and strong magnetic properties. Given that their applicability depends on their dimensions, crystal morphology, and surface chemistry, Fe3O4 NPs must be synthesized in a controlled, simple, and reproducible manner. Since conventional methods often lack tight control over reaction parameters and produce materials with unreliable characteristics, increased scientific interest has been directed to microfluidic techniques. In this context, the present paper describes the development of an innovative 3D microfluidic platform suitable for synthesizing uniform Fe3O4 NPs with fine-tuned properties. On-chip co-precipitation was performed, followed by microwave-assisted silanization. The obtained nanoparticles were characterized from the compositional and microstructural perspectives by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Moreover, supplementary physicochemical investigations, such as Fourier Transform Infrared Spectroscopy (FT-IR), Kaiser Test, Ultraviolet-Visible (UV-Vis) Spectrophotometry, Dynamic Light Scattering (DLS), and Thermogravimetry and Differential Scanning Calorimetry (TG-DSC) analyses, demonstrated the successful surface modification. Considering the positive results, the presented synthesis and functionalization method represents a fast, reliable, and effective alternative for producing tailored magnetic nanoparticles.

High hydrolytic activity of the metagenomic lipase LipC12 in deep eutectic solvents

Deep eutectic solvents (DESs) have been shown to increase the activity of lipases in biocatalytic processes, especially when added at intermediate concentrations. We evaluated the effect of DESs on the hydrolysis of p-nitrophenyl palmitate (p-NPP) by a metagenomic lipase, LipC12. The hydrogen bond acceptor was choline chloride (ChCl), while sorbitol (Sor), xylitol (Xyl), Glycerol (Gly), ethylene glycol (EG), triethylene glycol (TEG) and urea (U) were tested as hydrogen bond donors. The best results were obtained at 25% (v v−1) DES, with the increases in hydrolytic activity, compared to activity in buffer, being 18-fold for ChCl:Sor (2:1), and 10- to 12-fold for ChCl:Gly (1:2), ChCl:EG (1:2) and ChCl:Xyl (2:1). Dynamic Light Scattering analysis suggests that protein disaggregation played a key role in this activation: the hydrodynamic radius of LipC12 was 157 nm in buffer, but ranged from about 1 to 7 nm in DESs at different concentrations. The addition of 100 mM NaCl to the DES-containing media (at 25% v v−1 DES) slightly improved LipC12 activity. Addition of the hydrogen-bond donor alone also increased the p-NPP hydrolyzing activity with 30% (w v−1) sorbitol or xylitol giving 4.5-fold higher activities, compared to activity in buffer. Our fold-improvements in activity are the highest yet reported for the p-NPP-hydrolyzing activity of lipases and suggest that more studies are required, especially with other biocatalytic reactions such as esterification and transesterification.

Formulation of Silver Nanoparticles from Grewia Asiatica Leaf Extract and their Biomedical Applications

Nanotechnology is a well-advanced area and several types of nanoparticles have been synthesized. Different types of nanoparticles have been synthesized so far using different techniques. It is most practical to produce nanoparticles from plant extracts for use in medicine and other applications. In this study, silver nanoparticles were synthesized by Grewia asiatica leaf extract. Synthesized nanoparticles were characterized by different techniques including Ultraviolet-visible (UV) spectroscopy, X-ray diffraction (XRD), Dynamic light scattering (DLS), and Scanning electron microscopy (SEM). Results showed a characteristic peak of silver nanoparticles in UV-region at 425nm, while DLS analysis revealed the z-average size of synthesized particles i.e., 461.6nm and -28.4mV zeta potential. SEM analysis revealed the amorphous surface morphology. The antibacterial and antioxidant activity of silver nanoparticles were also evaluated. Silver nanoparticles showed significant antibacterial activity against both gram-positive and gram-negative bacteria. A maximum zone of inhibition of 16mm diameter was observed against Bacillus subtilis and Klebsiella pneumonia. While results of antioxidant activity showed a 43.27μg/ml IC50 value. In conclusion, Grewia asiatica leaf extract is a good source to synthesize silver nanoparticles. Also, green synthesized silver nanoparticles could act as potential antibacterial and antioxidant agents.

Synthesis of Ni2+-functionalized polydopamine magnetic beads for facilitated purification of histidine-tagged proteins

Facilitated purification of proteins, at a low cost and a short time, is one of the key steps in the industrial production of recombinant proteins. In the current study, polydopamine nanoparticles (PDA-NPs) are considered in the synthesis of magnetic beads for purifying recombinant proteins due to advantages such as biocompatibility/ biodegradability, easy synthesis, as well as the ability to directly chelate metal ions. They were synthesized in Tris buffer (pH: 8:5), then chelated with Fe3+(20 mg) and Ni2+ ions at concentrations of 2, 3, 5, and 7 mg/ml. Prepared nanoparticles were characterized through scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV-vis), dynamic light scattering (DLS), Inductively Coupled Plasma (ICP), and vibrating sample magnetometer (VSM). The size distribution of the particles was reported in the narrow range of 120–140 nm and 200 to 220 nm by the SEM image and DLS analysis, respectively. The chelation of ions on the surface of the nanoparticle was confirmed by the ICP technique with a magnetization of 35.42 emu/g. The highest adsorption rate of Ni2+ ions to polydopamine was obtained at a ratio of 1.4. The SDS-PAGE and western blot analysis confirmed the purification of eGFP and Hsp40 by PDA/Fe3+/Ni2+ at 26 and 40 kDa compared to the commercial nickel column. Moreover, the concentration of purified eGFP by PDA/Fe3+/Ni2+ was reported 138.83 µg/ml by the fluorescent signals, which is almost equal to or more than the protein purified by commercial Ni-NTA column (108.28 µg/ ml). The stability of PDA/Fe3+/Ni2+ has also been evaluated by ICP-OES for 10 days, and the result suggested that PDA magnetic beads were stable. Therefore, it can be concluded that PDA/Fe3+/Ni2+ have the ability to purify recombinant proteins in one less step and shorter time.

Production of Copper Nanoparticles by Aspergillus niger and Evaluation of their Biomedical Applications

Nanotechnology is a well advanced area and different types of nanoparticles are now produced. The most revolutionary topic of the twenty-first century is nanotechnology. Recently, metallic nanoparticles (NPs) have gained a lot of attention. In this study a straightforward, safe, and economical method is used for synthesizing copper nanoparticles (CuNPs) by using cell free filtrate of Aspergillus niger. Fungi secretes enormous amount of enzymes which act as reducing as well stabilizing agents. Synthesized CuNPs were characterized by different techniques. Ultraviolet (UV)-visible spectrophotometer showed a characteristic peak at 380nm, Dynamic Light Scattering (DLS) analysis indicated that CuNPs have average size of 570nm with 0.480 PDI. SEM (Scanning Electron Microscopy) revealed CuNPs are of cubic shape. As per FTIR (Fourier Transform Infrared Analysis) two functional groups i.e., -O-H- and C=C- on the surface of CuNPs. Genetic analysis of Aspergillus niger revealed the presence of nitrate reductase enzyme that may involve in reduction of metal into NPs. Furthermore, CuNPs showed significant antibacterial action against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Klebsiella pneumoniae with 17mm, 20mm, 17mm and 20mm respectively. CuNPs also showed antioxidant potential with 59.41µg/ml.
 Fungi secretes valuable enzymes with inherent ability to reduce metal ions into NPs. This reduced the cost of NPs synthesis and also synthesized NPs exhibit greater biomedical applications.

Dispersion stability analysis of copper sulphide nanoparticles in different medium

Nanoparticles (NPs) of covellite CuS have been synthesised using a modified polyol method at 160ºC - 165ºC without adding any extra surfactant. These NPs were charecterized by X-ray diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive Analysis of X-ray (EDAX), Zeta potential and Dynamic Light Scattering (DLS) techniques. XRD data and three Raman modes confirm P63/mmc space group and hexagonal crystal structure of CuS NPs. EDAX data of Cu:S was slight differed from nominal 1:1 ratio due to extra S taken in synthesis. FESEM images show sheet-like NPs. The zeta potential (ξ) data analysis shows that the stability of the NPs is dependent on the dispersion medium, with high stability observed above pH 8.93 in an acidic medium. At pH 10.95, a highest ξ value of -37.64 mV is recorded in de-ionized water (DIW), while the nanoparticles are found to be unstable in ethanol and propanol as dispersion mediums. According to the hydrodynamic diameter (HD) data, the particles tend to agglomerate more quickly in ethanol and propanol compared to DIW. These findings are expected to be useful in various applications such as pigments in paints, batteries, pharmaceuticals, ceramics, and waste water treatment.