Articles


Article published at 2024

Gold coating of maltodextrin-based cross-linked polymers by Vac Coat SEM coater DSR1

Researchers at University of Turin have developed cross-linked bio-derived cationic polymers from maltodextrin product to measure their water absorption capacity and water remediation capability as gel formation and nitrate, sulfate, and phosphate removal tests.

These polymers were comprehensively characterized via FTIR-ATR, TGA, DSC, XRD, SEM, elemental analysis, and zeta-potential measurements, to investigate their composition, and structure, along with other mechanical and chemical properties. For SEM imaging of the polymers, they were coated with a gold thin film of 12 nm with Vac Coat Desk Sputter Coater DSR1, and the SEM imaging of the polymers before and after the water adsorption are as follows:

The synthesized GLU-TTE polymer (Left) before and (Right) after swelling.
The synthesized GLU-TTE polymer (Left) before and (Right) after swelling.

Subsequently, the water absorption capacity of the cross-linked polymers was measured ranging from 800% to 1500%, and water remediation tests for removal of common pollutants like nitrate, sulfate, and phosphate showed high sorption rates, with 80% of nitrates, over 90% of sulfates, and total phosphates removal.

Vac Coat offers various SEM coaters for deposition of metals or carbon for SEM sample preparation working at low or high vacuum conditions. DSR1 is a low-vacuum desk sputter coater commonly used for noble metal sputtering deposition to make the surface of SEM samples conductive. DST1 with a turbomolecular pump, is capable of deposition of noble and oxidizing metals. Moreover, low and high-vacuum DCR and DCT carbon coaters can evaporate carbon fiber (thread) and carbon rods in a full/semi-automatic deposition process to prepare samples for SEM analysis. DSCR and DSCT hybrid coating systems merge the benefits of the sputter coaters and carbon coaters in one compact device, while DSCT-T adds the merit of thermal evaporation to the system. DTE and DTT coating models are ideal for the thermal evaporation of metals in a small or large chamber device, respectively.

Vac Coat also produces precise advanced research coating systems, such as triple target sputter coaters, DST3 and DST3-T, suitable for the deposition of multi-layers and alloys via co-sputtering. DST2-TG is another innovative Vac Coat product with double sputtering targets and a thermal source that can be fitted into a glove box through special feed-throughs.

Article published at 2024

FE-SEM characterization of neural cells with Vac Coat Sputter and Carbon coater

In a recent study, the role of the Indian herb Bacopa monnieri in treating oxidative stress in neuronal cells has been investigated through electron microscopy imaging. This study suggests that Bacopa monnieri and its active compounds could be used as a new drug for the prevention and treatment of oxidative stress-related neurodegenerative diseases as a natural remedy.

This article has investigated the therapeutic potential and molecular complexities of Bacopa monnieri, recognized for its neuroprotective and cognitive advantages, in treating neurological disorders and brain damage influenced by oxidative stress.

The morphological features of the cells in response to the methanolic extract of Bacopa monnieri (BME) and its active component, Bacoside-A, checked through FE-SEM characterization, show enhanced neuronal cell protection against oxidative stress as in neurodegenerative diseases. The neuronal cells grown over coverslips underwent the required treatments and then were mounted on carbon tape which was pasted on the sample holder stage and prepared for observation after gold coating with Vac Coat sputter and carbon coater, DSCR. The SEM observation was carried out using a Zeiss high-resolution microscope.

SEM images (Scale bar: 20 μm) showing the morphology of HT-22 cells pre-treated with BME and Bacoside-A in presence of oxidative stress.
SEM images (Scale bar: 20 μm) showing the morphology of HT-22 cells pre-treated with BME and Bacoside-A in presence of oxidative stress.

The below figures show the morphology of neural HT-22 cells pre-treated with BME in contrast to the non-treated cells in the presence of oxidative stress (H2O2 treatment), comparable to the control cells (Yellow arrows show the damaged membrane by oxidative stress). Maximum protection was obtained in both BME (100 µg/ml) and Bacoside-A treated cells, nearly the same as the control cells.

Article published at 2024

Fungal biodegradation of poly (butylene adipate-co-terephthalate)-polylactic acid-thermoplastic starch based commercial bio-plastic film at ambient conditions

Serious environmental pollution and human health issues can arise due to the enhanced utilization of synthetic plastics manufactured from petroleum resources. Therefore, biodegradable polymers (bio-plastics) made from renewable biological materials like natural aliphatic polyesters poly (lactide) (PLA), poly (butylene adipate-co- terephthalate) (PBAT), etc., are considered as eco-friendly plastics that last for a limited period of time in the environment.

In this paper, Ko et al. have studied the biodegradation of a hydrophilic ternary blend of PBAT-PLA with TPS (thermoplastic starch) by the act of fungal strains at ambient conditions. The surface morphology of the commercial bio-plastic films of PBAT-PLA-TPS was observed by scanning electron microscopy (SEM). The samples were prepared for the SEM analyses by mounting the films on a carbon tape and coating them with a 20 nm thickness platinum film using Vac Coat DSR1 ion sputter coater.

The optical and SEM images of the films with or without the fungal strains at different time intervals are shown below.

Yong article
Article published at 2024

Vac Coat DSR1 Utilized in SEM Sample Preparation for Evaluation of βcyclodextrin-based nanosponges Loaded with Budesonide for Pulmonary Delivery

Budesonide (BUD) is a hydrophobic compound utilized to treat chronic obstructive pulmonary disease. Francesco Trotta group at Turin University has tried a method to load BUD into the non-toxic and biocompatible βcyclodextrin-based nanosponges (βCD-NS), which resulted in an encapsulation efficiency of 81 ± 5.0 % for the optimized synthesis process.

SEM images of a) BUD; b) βCD-NS + BUD physical mixture; c) BUD-βCD-NS.
SEM images of a) BUD; b) βCD-NS + BUD physical mixture; c) BUD-βCD-NS.

The morphology of BUD, blank NS, and BUD-loaded NS was studied using scanning electron microscopy (SEM). The imaging is conducted using secondary electrons and 10 kV accelerating voltage, with the samples on the aluminum stub. Before SEM analysis, the polymers were coated by Vac Coat Desktop Sputter Coater model DSR1 with 12 nm of gold thin film.

This study demonstrated a longer duration of drug release and absorption from the lungs up to 12 h from BUD-βCD-NS structures, where the initial interval was 2 h for pure BUD. The results of this research suggest the BUD-loaded βCD-NS to be formulated as a dry powder inhaler and offer new insights into the future advancement of βCD-NS as a drug delivery system to achieve controlled release of therapeutic agents via the pulmonary route.

Article published at 2024

Scanning Electron Imaging of DSR1 Gold Coated Bio-polymers as an Adsorbent of Salicylic Acid in Water

Starch-based bio-adsorbents were successfully observed by SEM, previously prepared through coating a 12 nm gold thin film on the non-conductive bio-based beta-cyclodextrins and maltodextrins. The gold was coated by using the DSR1 SEM coater, a popular Vac Coat ion sputter coater suitable for electron microscopy sample preparation.

The researchers at the University of Turin in Italy worked on the removal of environmentally hazardous salicylic acid in wastewater and surface waters utilizing cross-linked adsorbents derived from starch, like beta-cyclodextrins and maltodextrins. These hydrophilic granular structures showed more than 90% salicylic acid removal with a maximum adsorption capacity of 17 mg.g-1 and recycling up to for cycles.

The samples went through SEM for structural analysis to study the morphology of the biopolymers. The samples were coated with a 12 nm gold thin film by Vac Coat DSR1 low-vacuum sputter coater as an SEM preparation step to enhance the conductivity and reduce charge accumulation on the samples’ surface.

Microscope images and SEM characterization of polymer granules. Scale bars: 250 μm (first line); 200 μm (second line); 50 μm (third line); 10 μm (fourth line)
Microscope images and SEM characterization of polymer granules.

Preparation of the samples for electron microscopy is crucial to improve the imaging results. Vac Coat SEM coaters, such as sputter coaters, carbon coaters, and thermal evaporators are ideal coating devices for coating different conductive layers on electron microscope samples’ surfaces.

Article published at 2024

Assembly of Colloidal Crystals by Local Heating Induced Through Plasmonic Effect of A Gold Thin Film Deposited by Vac Coat DTT

Leipzig university researchers have coated coverslips with a thin (less than 50 nm) gold film and 5 nm chrome adhesion layer by Vac Coat DTT model to study optically induced 2D and 3D colloidal crystals through dynamic thermofluidic assembly. The results of this research has been published as a journal article in Frontier in Nanotechnology, with the title “Thermofluidic assembly of colloidal crystals” by D. Quinn and F. Cichos in March, 2023.

Crystalline structures as crystalline colloids demonstrate remarkable photonic features, useful in modulation of electromagnetic wave propagation. These structures can be formed in various methods, such as engineering inter-particle interactions, applying external electro-magnetic fields, using optical tweezers, or thermally induced processes, in which local heating of a plasmonic structure like a thin gold film is used to induce a temperature gradient to create/destroy crystalline colloids.

Vac Coat Desktop Thermal Evaporator, DTT, is a high-vacuum coating machine suitable for uniform deposition of different source materials like gold, silver, chrome, etc., by thermal evaporation method. DTT contains three resistive boat/basket source holders, and can be used for simultaneous material deposition if supplied with multiple high-current power supplies (optional).

Schematic of the temperature measurement using the 5CB technique
Schematic of the temperature measurement using the 5CB technique.
Article published at 2024

Study of DSR1 Sputter Coater Gold Coated Polysulfone Membranes Modified by PAA

In the research work done by Plisko T., et al., the polysulfone ultrafiltration membranes were modified by addition of polyacrylic acid to increase their antifouling performance. These insulating membranes were coated with a thin gold layer by DSR1 sputter coater for structural analysis by SEM imaging.

Membrane fouling caused by the sorption of feed mixture particles on the surface and inside pores of the membrane selective layer leads to membrane performance degradation and is a serious problem in membrane technology. 

SEM micrographs in “Effect of the Addition of Polyacrylic Acid of Different Molecular Weights to Coagulation Bath on the Structure and Performance of Polysulfone Ultrafiltration Membranes”

Plisko T., et al., modified these ultrafiltration membranes by the addition of polyacrylic acid (PAA) with different molecular weight and concentrations to reach maximum antifouling performance of 136% for 450,000 g·mol−1 PAA.

The influence of PAA molecular weight on different membrane properties, such as surface roughness, water contact angle, zeta potential, the separation, and antifouling performance were experimented. SEM imaging is used to study the insulating structure of these gold coated samples.

It was found that PAA-modified membranes present smaller pore size and porosity, along with greater hydrophilicity and higher values of negative charge of membrane surface.

Article published at 2024

Vac Coat DSCR Used in SEM Investigation of Amphiphilic Chitosan/18β-Glycyrrhetinic Acid Nanoparticles for Anti-Photoaging Effects

The 18β-glycyrrhetinic acid (NGA) nanocrystals prepared by adsorption of amphiphilic chitosan (ACS) with 10:1 optimal ratio of NGA to ACS was used to prepare ANGA composites, which was utilized to prevent and treat skin photoaging. The results of this article indicated that the NGAs could significantly enhance the photoaging of mouse skin, so the ANGA hydrogel could be used to counteract skin photoaging.

Scanning electron micrographs of NGAs (A) and ANGAs (B)
Scanning electron micrographs of NGAs (A) and ANGAs (B).

The shape of the ACS coated NGA nanoparticles were studied by SEM characterization after completely drying under vacuum and fixing on a conductive tape. The SEM images of the sample coated with gold for 2 min using Vac Coat DSCR sputter coater, under an excitation voltage of 5 kV, is shown below.

Article published at 2024

Vac Coat Magnetron Sputter Coater for SEM Investigation of Polymeric Structures

Nowadays, production of biodegradable polymers that do not contribute to microplastic burdens is a worldwide environmental challenge, which is going to be overcome through polymer engineering.

Kim, et al. at University of Waterloo have investigated highly filled thermoplastic polyurethanes (TPU) composite systems using a polysaccharide, α-1,3-glucan, as a renewable and sustainable filler material in their research work entitled as “Engineered polysaccharide alpha-1,3-glucan in highly filled thermoplastic polyurethane systems”, which improved the modulus and strength of TPU.

The α-1,3-glucan particles were gold-coated by Vac Coat magnetron sputter coater in order to become observable with scanning electron microscope.

Vac Coat DSR1 is a low-cost SEM coater for deposition of a thin film of non-oxidizing materials, like gold and silver. Vac Coat also offers high-vacuum sputter coater, DST1, and low and high-vacuum carbon coaters, DCR and DCT, for SEM, FESEM and TEM imaging.

α-1,3-glucan particles observed with scanning electron microscope
α-1,3-glucan particles observed with scanning electron microscope.

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