Enhanced Antibacterial Activity of Poly (dimethylsiloxane) Membranes by Incorporating SiO2 Microspheres Generated Silver Nanoparticles

The nonspecific adsorption of proteins and bacteria on the surface of polydimethylsiloxane (PDMS) had been a serious concern in a wide range of applications, such as medical devices. In order to improve the anti-adhesive and antibacterial capability, bare silver nanoparticles (AgNPs, ~15 nm) were generated in-situ on their surface without extra reducing and stabilizing agents. The main reason for this was that the SiO2 microspheres that are covalent bonded to the bulked PDMS could not only generate AgNPs spontaneously but also insure that no AgNPs were released to the environment. Meanwhile, the thiol-group-functionalized SiO2 microspheres self-assembled on the surface of PDMS by thiol-vinyl click reaction without any impact on their biomedical applications. After the modification of SiO2 microspheres with AgNPs, the surface of PDMS showed a smaller water contact angle than before, and the adhesion and growth of E. coli and Bacillus subtilis were effectively inhibited. When the monolayer of SiO2 microspheres with AgNPs was assembled completely on the surface of PDMS, they present improved bacterial resistance performance (living bacteria, 0%). This approach offers an antibacterial and anti-adhesive surface bearing small and well-defined quantities of in-situ generated AgNPs, and it is a novel, green, simple, and low-cost technique to generate AgNPs on soft biomedical substrates.

Download Full-text

Nanocomposite cellulose fabrics with in situ generated silver nanoparticles by bioreduction method

Journal of Industrial Textiles ◽

10.1177/1528083720924731 ◽

2020 ◽

pp. 152808372092473 ◽

Cited By ~ 1

Author(s):

Suchart Siengchin ◽

Pawinee Boonyasopon ◽

Vajja Sadanand ◽

Anumakonda Varada Rajulu

Keyword(s):

Silver Nanoparticles ◽

Size Range ◽

Low Cost ◽

Aqueous Dispersion ◽

X Ray Diffraction ◽

X Ray ◽

Gram Positive Bacteria ◽

Bed Materials ◽

Cellulose Fabrics

In the present work, nanocomposite cellulose fabrics with in situ generated silver nanoparticles were prepared by bioreduction method employing aqueous dispersion of low-cost natural turmeric powder as a reducing agent and different concentrated aqueous AgNO3 as source solutions. The prepared nanocomposite cellulose fabrics were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and antibacterial tests. The nanocomposite cellulose fabrics had roughly spherical silver nanoparticles in the size range of 41–130 nm with an overall average of 78 nm. The X-ray analysis indicated the generation of both silver nanoparticles and Ag2O nanoparticles in the nanocomposite cellulose fabrics. The nanocomposite cellulose fabrics retained the generated AgNPs even after repeated detergent washings. The prepared nanocomposite cellulose fabrics exhibited excellent antibacterial activity against both the Gram-negative and Gram-positive bacteria and hence can be considered as antibacterial hospital-bed materials, apparels, etc.

Download Full-text

Low Cost and Compact FMCW 24 GHz Radar Applications for Snowpack and Ice Thickness Measurements

Sensors ◽

10.3390/s20143909 ◽

2020 ◽

Vol 20 (14) ◽

pp. 3909

Author(s):

Patrick Pomerleau ◽

Alain Royer ◽

Alexandre Langlois ◽

Patrick Cliche ◽

Bruno Courtemanche ◽

...

Keyword(s):

Snow Depth ◽

Continuous Wave ◽

Snow Water Equivalent ◽

Low Cost ◽

Ice Thickness ◽

Lake Ice ◽

Wide Range ◽

Thickness Measurements ◽

24 Ghz

Monitoring the evolution of snow on the ground and lake ice—two of the most important components of the changing northern environment—is essential. In this paper, we describe a lightweight, compact and autonomous 24 GHz frequency-modulated continuous-wave (FMCW) radar system for freshwater ice thickness and snow mass (snow water equivalent, SWE) measurements. Although FMCW radars have a long-established history, the novelty of this research lies in that we take advantage the availability of a new generation of low cost and low power requirement units that facilitates the monitoring of snow and ice at remote locations. Test performance (accuracy and limitations) is presented for five different applications, all using an automatic operating mode with improved signal processing: (1) In situ lake ice thickness measurements giving 2 cm accuracy up to ≈1 m ice thickness and a radar resolution of 4 cm; (2) remotely piloted aircraft-based lake ice thickness from low-altitude flight at 5 m; (3) in situ dry SWE measurements based on known snow depth, giving 13% accuracy (RMSE 20%) over boreal forest, subarctic taiga and Arctic tundra, with a measurement capability of up to 3 m in snowpack thickness; (4) continuous monitoring of surface snow density under particular Antarctic conditions; (5) continuous SWE monitoring through the winter with a synchronized and collocated snow depth sensor (ultrasonic or LiDAR sensor), giving 13.5% bias and 25 mm root mean square difference (RMSD) (10%) for dry snow. The need for detection processing for wet snow, which strongly absorbs radar signals, is discussed. An appendix provides 24 GHz simulated effective refractive index and penetration depth as a function of a wide range of density, temperature and wetness for ice and snow.

Download Full-text

MISIRoot: A Robotic Minimum Invasion in Situ Imaging System for Plant Root Phenotyping

10.21203/rs.3.rs-25184/v1 ◽

2020 ◽

Author(s):

Zhihang Song ◽

Wei Qiu ◽

Jian Jin

Keyword(s):

Plant Protection ◽

Plant Root ◽

Low Cost ◽

3D Structure ◽

Color Images ◽

Plant Roots ◽

Natural Soil ◽

Wide Range ◽

Root Phenotyping

Abstract Background: Plant root phenotyping technologies play an important role in breeding, plant protection, and other plant science research projects. The root phenotyping customers urgently need technologies that are low-cost, in situ, non-destructive to the roots, and suitable for the natural soil environment. Many recently developed root phenotyping methods such as minirhizotron, X-CT, and MRI scanners have their unique advantages in observing plant roots, but they also have disadvantages and cannot meet all the critical requirements simultaneously. Results: The study in this paper focuses on the development of a new plant root phenotyping robot that is minimally invasive to plants and working in situ inside natural soil, called “MISIRoot”. The MISIRoot system mainly consists of an industrial-level robotic arm, a mini-size camera with lighting set, a plant pot holding platform, and the image processing software for root recognition and feature extraction. MISIRoot can take high-resolution color images of the roots in soil with minimal disturbance to the root and reconstruct the plant roots’ three-dimensional (3D) structure at an accuracy of 0.1 mm. In a test assay, well-watered and drought-stressed groups of corn plants were measured by MISIRoot at V3, V4, and V5 stages. The system successfully acquired the RGB color images of the roots and extracted the 3D points cloud data containing the locations of the detected roots. The plants measured by MISIRoot and plants not measured (control) were carefully compared with the results from the Hyperspectral Imaging Facility (reference). No significant differences were found between the two groups of plants at different growth stages. Conclusion: The MISIRoot system recently developed at Purdue University has been proved effective in root phenotyping with multiple advantages: With a comparatively low cost and minimal invasion to the plant, this system can automatically measure the root’s 3D structure and take color images of the roots in ordinary soil media, and in situ. This system provides a new option for root phenotyping researchers and has a potential to be applied in a wide range of research topics such as breeding, plant protection and so on.

Download Full-text

Catechol End-Functionalized Polysarcosine for In-situ Synthesis and Stabilization of Silver Nanoparticles

MRS Advances ◽

10.1557/adv.2020.141 ◽

2020 ◽

Vol 5 (21-22) ◽

pp. 1113-1120

Author(s):

Hailemariam Gebru ◽

Zhenjiang Li

Keyword(s):

Silver Nanoparticles ◽

Metallic Nanoparticles ◽

In Situ Synthesis ◽

High Concentration ◽

Ag Nps ◽

Sem Images ◽

Stabilizing Agents ◽

H Nmr ◽

Dopamine Hydrochloride

ABSTRACTFunctional polymers were previously employed to minimize the susceptibility of metallic nanoparticles (MNPs) for aggregation. Herein, we intended to conjugate catechol moiety into the polymer chain end considering its anchoring ability to virtually most surfaces. Accordingly, catechol end-functionalized polysarcosine (cat-PSar) was successfully prepared from the ring-opening polymerization (ROP) of sarcosine N-carboxyanhydrides (Sar-NCA) using dopamine hydrochloride initiator. ROP of Sar-NCA was carried out at different monomer to initiator feed ratios. The molecular structure of cat-PSar was confirmed by 1H NMR and MALDITOF. Afterward, the obtained catechol functionalized polymer was used for in-situ synthesis and stabilization of silver nanoparticles (Ag-NPs) in aqueous solution. The observed characteristic absorption peak at λmax of 415 nm indicates the formation of Ag-NPs. Scanning electron microscope (SEM) images also elucidate the formation of Ag-NPs with the relatively small sizes of the nanocomposite at a high concentration of silver nitrate. Hence, biomimetic polymers could play a dual role as reducing and stabilizing agents in the preparation of monodispersed MNPs.

Download Full-text

Light-Mediated Green Synthesis of DNA-Capped Silver Nanoparticles and Their Antibacterial Activity

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.16517 ◽

2020 ◽

Vol 20 (3) ◽

pp. 1678-1684

Author(s):

Jiraporn Chumpol ◽

Sineenat Siri

Keyword(s):

Silver Nanoparticles ◽

Green Synthesis ◽

Light Exposure ◽

Low Cost ◽

Reaction Times ◽

Antibacterial Activities ◽

Face Centered Cubic ◽

Stabilizing Agents ◽

Face Centered ◽

Average Size

Green synthesis offers an eco-friendly and low-cost approach for the synthesis of silver nanoparticles (AgNPs). Many studies have reported on the use of biomolecules, especially plant extracts, as reducing and/or stabilizing agents in place of toxic chemicals. This study reports on the use of bacterial genomic DNA as an alternative stabilizing agent for the green synthesis of AgNPs under light activation. With both increased DNA quantities and reaction times under light exposure, more stabilized AgNPs formed as indicated by the surface plasmon resonance intensities. The synthesized AgNPs were spherical with an average size of 61.36±10.15 nm as calculated using the dynamic light scattering (DLS) technique. The X-ray diffraction, selected area electron diffraction, and high resolution transmission electron microscope (TEM) analyses confirmed the formation of face-centered cubic (fcc) structured AgNPs. The produced AgNPs exhibited antibacterial activities against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, suggesting its potential application as an antibacterial agent.

Download Full-text

Synthesis of Triazoles by Electro-Assisted Click Reaction Using a Copper Foil Electrode

Journal of the Brazilian Chemical Society ◽

10.21577/0103-5053.20210035 ◽

2021 ◽

Author(s):

Luceldi Carre-Rangel ◽

Karla Espinoza ◽

Mercedes Oropeza-Guzmán ◽

Ignacio Rivero

Keyword(s):

Copper Foil ◽

Click Reaction ◽

Reference Electrode ◽

Process Efficiency ◽

Water Medium ◽

Click Reactions ◽

Onset Potential ◽

Wide Range ◽

Biological Environment

This paper presents an innovative pathway for the synthesis of triazoles using the well-known “click chemistry” assisted by the electrochemical oxidation of metallic Cu0. The click reaction is used to couple a wide range of biological interest compounds. In this case, faster and less polluting methods for a biological environment was achived by in situ Cu0 electrooxidation, providing the suitable quantity of catalyst required by click reaction. The electrochemical cell was composed of a copper foil as the working electrode, a platinum wire serving as a counter electrode, and an Ag/AgCl wire as the reference electrode. Linear anodic sweep voltammetry in a tert-butanol-water medium (1:1), an electrolyte of tetrabutylammonium tetrafluoroborate (TBATFB), showed the onset potential of Cu0 electrooxidation. Using the same electrode configuration three different triazoles were prepared under constant electrode potential, in a short time (60 min), and splendid yields (78-90%). These results indicate that the in situ CuI formation occurs on the surface of the copper foil. A pulse potential program has also been implemented in which a yield of 92% was achieved, reducing electrode passivation and consequently increasing the process efficiency. The electroassisted click reactions are highly efficient to produce triazoles by an innovative electrochemical reaction. The products were characterized by infrared (IR), nuclear magnetic resonance (1H and 13C NMR), and mass spectrometry (MS).

Download Full-text

The development of “fab-chips” as low-cost, sensitive surface-enhanced Raman spectroscopy (SERS) substrates for analytical applications

The Analyst ◽

10.1039/c4an01633e ◽

2015 ◽

Vol 140 (3) ◽

pp. 779-785 ◽

Cited By ~ 30

Author(s):

Ashley M. Robinson ◽

Lili Zhao ◽

Marwa Y. Shah Alam ◽

Paridhi Bhandari ◽

Scott G. Harroun ◽

...

Keyword(s):

Raman Spectroscopy ◽

Silver Nanoparticles ◽

Chemical Sensing ◽

Low Cost ◽

Surface Enhanced Raman Spectroscopy ◽

Sers Substrates ◽

Sensing Applications ◽

Wide Range ◽

Surface Enhanced ◽

Surface Enhanced Raman

Modification of metal-coated zari fabric chips with silver nanoparticles results in sensitive, affordable SERS substrates which are useful for a wide range of chemical sensing applications.

Download Full-text

Reactive Conductive Ink Capable of In Situ and Rapid Synthesis of Conductive Patterns Suitable for Inkjet Printing

Molecules ◽

10.3390/molecules24193548 ◽

2019 ◽

Vol 24 (19) ◽

pp. 3548 ◽

Cited By ~ 2

Author(s):

Yuehui Wang ◽

Dexi Du ◽

Zhimin Zhou ◽

Hui Xie ◽

Jingze Li ◽

...

Keyword(s):

Silver Nanoparticles ◽

Sheet Resistance ◽

Sodium Borohydride ◽

Inkjet Printing ◽

Low Cost ◽

Treatment Temperature ◽

Water Mixture ◽

Photographic Paper ◽

Conductive Pattern

We report a fabrication method of the conductive pattern based on in situ reactive silver precursor inks by inkjet printing. The reactive silver precursor inks were prepared with ethylene glycol and deionized water mixture as the solvent, and silver nitrate as silver source. Sodium borohydride solution as the reducing agent was first coated on photographic paper by screen printing process, and then dried at 50 °C for 4 h. Furthermore, the reactive silver precursor inks were printed on a photographic paper coated with sodium borohydride using inkjet printing to form silver nanoparticles in situ due to redox reaction, and thus a conductive pattern was obtained. The effects of the reactive silver precursor ink concentration and printing layer number and treatment temperature on the electrical properties and microstructures of the printed patterns were investigated systematically. The size range of in situ-formed silver nanoparticles was 50–90 nm. When the reactive silver precursor ink concentration was 0.13 g/mL, the five-layer printed pattern exhibited a sheet resistance of 4.6 Ω/γ after drying at room temperature for 2 h; furthermore, the sheet resistance of the printed pattern decreased to 1.4 Ω/γ after drying at 130 °C for 2 h. In addition, the display function circuit was printed on the photographic paper to realize the display of the numbers 0–99. It provides new research ideas for the development of environmentally friendly and low-cost flexible paper-based circuits.

Download Full-text

Low-Cost Synthesis and Characterization of Silver Nanoparticles for Diverse Sensing Application

Engineering, Technology & Applied Science Research ◽

10.48084/etasr.2450 ◽

2019 ◽

Vol 9 (2) ◽

pp. 3915-3917

Author(s):

S. Akhtar ◽

Z. Farid ◽

H. Ahmed ◽

S. A. Khan ◽

Z. N. Khan

Keyword(s):

Silver Nanoparticles ◽

Chemical Reduction ◽

Low Cost ◽

Industrial Applications ◽

X Ray Diffraction ◽

Ag Nps ◽

X Ray ◽

Wide Range ◽

Range Of Functions

Silver (Ag) nanoparticles (NPs) are synthesized and characterized by a low-cost chemical reduction method. Silver nanoparticles (Ag NPs) have pre-occupied the consideration of the scientific community due to their wide range of functions, utility and industrial applications, particularly in the fields of sensing technologies and medicine (particularly their efficiency against microbes, the ability of healing the wound and anti-inflammatory properties). Ag NPs are synthesized by a low-cost fabrication method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray diffraction (EDX) and photometry techniques are used in this work to identify their nature and potentiality for diverse applications in sensing technologies.

Download Full-text

Modification of Waste Leather Trimming with in Situ Generated Silver Nanoparticles by One Step Method

Applied Science and Engineering Progress ◽

10.14416/j.asep.2021.01.007 ◽

2021 ◽

Vol 14 (2) ◽

Author(s):

Basa Ashok ◽

Mallavarapu Umamahesh ◽

Natarajan Hariram ◽

Suchart Siengchin ◽

Anumakonda Varada Rajulu

Keyword(s):

Silver Nanoparticles ◽

Silver Oxide ◽

Low Cost ◽

Step Method ◽

Mean Size ◽

One Step ◽

Silver Oxide Nanoparticles ◽

Inhibition Zones ◽

Xrd Studies

Waste leather trimming (WLT) was modified by in situ generation of silver nanoparticles (AgNPs) and silver oxide nanoparticles (Ag2ONPs) by one step thermal assisted method. The modified WLT was analyzed by FTIR, SEM, EDS, XRD and TGA techniques and antibacterial analysis. The generated silver based nanoparticles had a mean size of 93 nm. The FTIR spectra revealed no major changes between WLT and modified WLT. The XRD studies indicated additional peaks in the diffractogram of modified WLT which belonged to AgNPs and Ag2ONPs. The unmodified WLT had four inflection temperatures at 89, 303, 454, and 785°C while these values for the modified WLT were 84, 211, 305, and 328°C indicating a slight lowering of thermal stability due to the catalytic activity of the generated silver based nanoparticles. Further, the modified WLT formed the inhibition zones against E.coli, P.aeruinosa, S.aeureus and B.lichinomonas bacteria with diameters of 33, 36, 29, and 30 mm respectively. Hence, the modified WLT can be considered as filler for making low cost antibacterial biocomposites.

Download Full-text