Self-Assembly of Au nanoparticle and Zn(NO3)2 Nanocubes

Utkur MirsaidovI from the National University of Singapore was able to view the self-assembly of Au nanoparticle and Zn(NO3)2 nanocubes under the effects of a Transmission Electron Microscopy (TEM) beam and appropriate dark image processing using averaging and DRIFTS.

The nucleation phenomenon of gold nanocrystals from a Au(III) Chloride solution was preceded by observed phases that allow the condensation of atoms in a region. This condensation enables the formation of amorphous nanoclusters and is followed by nanocrystal formation and growth. As reported in Symposium SM07.01.01, Mirsaidovl’s team found that an electron beam can significantly affect the nucleation process because at higher beam intensities, the nucleation time of the Au(III)Cl solution could be accelerated. The beam then acts as a reducing agent, causing changes from the ionic Au3+ state to the metallic Au0

But electron beams can sometimes damage or even destroy samples, such as seen by the Metal Organic Frameworks (MOFs) of Zn(NO3)2. This material is of cubic highly crystalline structure that could be imaged using TEM and can be viewed but the data collection must be made at intensities so low that the nucleation process is invisible. However, using image averaging and DRIFTS, the researchers were able to view the aggregation of the Zn(NO3)2 nanocubes in the same stepwise fashion as the gold nanoparticles (from solution, to dense fluid, to aggregates and finally to crystal). 

If you are interested in learning more about Zn(NO3)2 MOFs or Au nanoparticles click here to view Dr. MirsaidovI’s presentation on the MRS Spring Meeting and Exhibit.


Tutorial SM07: use of SINGLE for Liquid TEM analysis

Jungwon Park from Seoul National University presented how to experimentally prepare samples for liquid Transmission Electron Microscopy (TEM) and how to then manage the image data using 3-D SINGLE in order to accurately describe metal nanostructures.

The presentation began with an excellent explanation of nucleation theory and the main ideas behind classical nucleation and non-classical (also known as two-step nucleation) which are types of growth that can be observed. Then continued to show how the team has incorporated the 3-D Structure Identification of Nanoparticles by using Graphene Liquid cell Electron microscopy (SINGLE) technique to their present research on metal nanoparticles. SINGLE has the capability to analyze samples inside a liquid, give a full coverage of rational angles and present heterogeneity between individual particles; properties that are beneficial if one wishes to determine the structure at the nanoscale using. The imaging process begins with a frame averaging and particle tracking procedures but must include a graphene subtraction, followed by a 2-D clustering that permits the initial model generation and gives way for the final 3-D reconstruction. 

Dr. Park explained how they can also use a graphene - anodized aluminum oxide - graphene sandwiched substrate, to achieve a statistically significant sample size of cells (70nm - 340nm in diameter) that are well suited for liquid TEM by filling up the pores of the anodized aluminum oxide with a colloidal solution of interest. 

Dr. Park’s team and collaborators did an amazing job that is worth noting. If you feel like you might want to mingle with the SINGLE technique click here to find the presentation at the end of the Tutorial SM07.


Tutorial SM07: PbSe Nanoparticle Self-Assembly

Haimei Zheng, from UC-Berkeley showed how at times of adversity, simple solutions can yield extraordinary results. The team was able to identify the steps by which PbSe nanoparticles can join to form a variety of interesting nanostructures.

The technique of liquid cell Transmission Electron Microscopy (TEM) is a type of electron microscopy that can affect the sample area that is subject to the irradiation. The main issues with this technique include the possible reactions (cause by heating, ionization or knock-on), damage to the surface, and small volume capacity. However, Liquid Cell TEM does have good properties that allow for direct imaging of the surface, an atomic scale resolution and a constrained environment. A previous study of the material of interest is recommended in order to predict if a reaction is possible or favorable. 

Beginning from a PbSe colloidal solution, this researcher observed that the structure of the PbSe particles was influenced by the removal of the ligands. After some clever choice of ethylenediamine instead of ethylene glycol it was seen that two nanoparticles approach each other, and form a neck that then grows and links two distinct nanoparticles to form the starting of a nanochain structure of PbSe.

If you are registered for the "MRS Spring Meeting and Exhibit" and want to learn more about Haimei Zheng's self-assembly via liquid cell TEM click here to see their video conference.


Tutorial ASM.01: STEM-in-SEM—How to Maximize Their Use.

From detectors to diodes and from Bright Field to Dark Field microscopy Jason Holm explains how to get the very best out of STEM-in-SEM equipment and how to create your own equipment accessories for optimal results.

In this tutorial video conference by Jason Holm from the National Institute of Standards and Technology, he presented the various imaging and surface analysis techniques that one can do with most STEM-in-SEM equipment. He highlighted the importance of measuring the camera length from the sample in order to adjust the parameters to better fit the sample.  And highlighted that, once the beam is adjusted and centered, one should only use base movements to scan the sample; this tends to help produce better images. And then he shared how, when dealing with organic samples, using SEM with sputtering or staining might not give the best results.

We can use 4D analysis by taking our sample and then take subsequent measurements of a portion in the same sample. If we have the coordinates of our sample in (X, Y) then the coordinates of our inner portion can be expressed as (x, y). This can readily be defined as a four dimensional analysis of the surface, which can be handled by either a synchronized or an automated method to gather data from the region of interest.

If you are registered for the MRS Spring Meeting and Exhibit and want to learn more about STEM-in-SEM, click here.


#S21MRS Blogger: Sebastián

20210415_161426(3)       I am Sebastián Suárez Schmidt, an undergraduate Physics student, researcher and volunteer writer for the MRS Bulletin. My scientific research is stationed at the University of Puerto Rico Rio Piedras campus in Puerto Rico, where I’ve specialized in the development of anodized aluminum layers for the growth of nanowires that can serve in the sensing of gases at trace amounts.

         

     This year I will be working alongside the skilled team of MRS writers to bring you an experience that allows for the immersion of the readers into the conferences, tutorials, and even the live yoga events! Because of the COVID pandemic, we have relied on the powerful advances in virtual presentation and interaction; however, this will not discourage or hinder the learning and networking opportunities that the MRS Spring Meeting & Exhibit will provide. If you are interested in the marvelous artistic applications of scientific imaging I encourage you to check out the Science as Art Competition and vote for your favorite. Look forward to meeting as many of you as possible, while we work hard and push forward in the field of Material Science.

 

Stay safe.

Kind regards.

 

 

Sebastián Suárez Schmidt


Hello World!

First blog, first virtual conference and first MRS meeting! That's my view of the 2021 virtual MRS spring meeting and exhibit that I will be sharing with you; a view of a fresh(wo)man ;) My name is Essraa Ahmed and I would like to invite you to explore this year's MRS spring meeting with me!

I'm a PhD student at Hasselt University in Belgium, working on charge transfer between diamond electrodes and Cyanobacteria. Our research group, Wide Band Gap Materials (WBGM), specializes in novel wide bandgap semiconductors such as diamond, aluminium nitride and boron nitride. You can find more about our research group on this website. Many of the talks at #S21MRS that I will be covering in this blog will be related to energy and sustainability, structural materials and other topics closer to my field of study. But, the promise is to diversify by including other research areas.

Like most of our scientific activities nowadays, this meeting is virtual and we all know that comes with many challenges. For tips and tricks on improving productivity, I recommend to check this MRS blog. Why not give these tips a try? they seem to have worked for me! For a fun start, check out the Science as Art competition and vote for your favourite. From fun to fabulous, your eye will enjoy this journey of visual stimuli. Keep safe and stay tuned!

 


F20MRS Meeting: Soft Electrically-Driven Actuators for Wearable Haptics

For me personally, the talks and live panels on virtual reality (VR) were the most interesting and engaging talks as it is wonderful to see how scientists are developing heptic devices that could bring stimulated sense of touch in a way that we could feel the texture and sense the virtual structures.

Why don’t we have haptic suits with thousands of individual actuators (taxels) when every smartphone display has millions of individually addressed pixels? To answer that, Dr. Shea from EPFL has tried to give us his perspective obout this field and the challenges ahead.

Dr. Shea addresses the challenges very delicately: generating localized forces on the human body in a comfortable and safe way is a major challenge for soft actuation: both fast motion and high forces are needed, yet the device must conform to the human body, and consume low power

Dr. Shea's lab has focused on electrostatic actuation, using high electric fields to deform elastomers or textile structures. They have developed a textile-based brakes, with a fine thickness of 1 mm , that can effectively block the motion of two sliding strips in a few milliseconds and control the joint motion. Using such a technology, users could manipulate virtual objects much better with more accuracy and feel deeper immersion. 

Their new fabrication method allows for high forces for use in full-body kinesthetic haptics by blocking shoulder and elbow motion to so that we could feel  for instance how heavy an object is to push and feel it's "weight". Thier method also generate normal and shear forces with high spatial resolution, that allows mimicking different feeling such as if something is about to slip out of our hands.

There is definitely much more to learn by watching Dr. Shea's talk on MRS meeting website using this link.


F20MRS Meeting: Towards Solid-State Batteries for Electric Vehicles

Dr. Doeff is a Senior Scientist and member of the Electrochemical Technologies Group (ECT) at Lawrence Berkeley National Laboratory. She is mainly working on sodium and lithium polymer batteries and more interestingly all-solid Li-ion batteries.

During this year's MRS meeting, Dr. Doeff has delivered a very informative talk about ceramic-based electrolytes and the challenges which exist for their design and application in vehicles. 

All-solid-state lithium batteries are advantageous against lithium-ion batteries as they could offer better energy density, safety, and reliability. The main problem with the current thin-film configurations is that their practical energy density is low and require expensive vacuum technologies to develop and scale.

Dr. Doeff and her coworkers at LBNL are developing a scalable freeze tape casting method to produce porous ceramic structures of LLZO (oxide-based solid electrolyte that is stable toward Li metal) to be used for all-solid-state lithium-ion batteries.

The microscopy work combined with synchrotron tomography that they have employed makes this talk very interesting and informative!

To watch this talk please use this link.

 


Engineering innate immune-mediated cancer cell killing by antibody recruiting macromolecules

F.SM07.04.11 Engineering innate immune-mediated cancer cell killing by antibody recruiting macromolecules

Annemiek Uvyn, Ghent University

Antibody therapy focuses on targeting antibodies onto the surface of cancer cells by innate immune mechanisms such as complement activation, antibody-dependent cell-mediated cytotoxicity, or antibody-dependent cellular phagocytosis to induce cancer cell killing. Monoclonal antibody therapy is limited in its high cost and side effects. And the research work lead by Annemiek Uvyn, from Ghent University, suggests that using synthetic systems that can recruit endogenous antibodies onto cancer cell surfaces can be a viable alternative for antibody therapy.

The research group works on developing antibody-recruiting polymers that can be used for cancer immunotherapy. These antibody recruiting polymers contain a target binding domain (to bind to the cell surface ) and an antibody binding domain (to bind to the antibody F-ab region). They can be injected directly into tumors to induce their attachment to cancer cell surfaces at one end and covalently attach the endogenous antibodies at the other. This binding would thus recruit immune cell-mediated cancer killing.

Interestingly, Annemiek says that a lipid anchor inserted into the phospholipid cell membrane is being used to covalently conjugate to the glycocalyx of metabolically azido-labeled cells. And azido-labelling becomes crucial to enhance the binding efficiency of antibody recruiting polymers (DBCO or DNP polymers) on to the cells. In vitro analysis of the polymers with cancers showed that a dialkyl group lipid polymer attached to cancer cells could high efficiently recruit anti-DNP into the cell surface. Eventually, the polymer conjugated cancer cell killing efficiency was visualized with macrophages to show phagocytosis is being activated with the lipid polymers. This approach of developing antibody-recruiting polymers can revolutionize monoclonal antibody cancer immunotherapy.


Fundamentals/Therapeutics: F.GI01.11: Live Keynote III

Fundamentals/Therapeutics: F.GI01.11: Live Keynote III

F.GI01.01.03 Membrane Based Affinity Capture to Quantify Antibodies to COVID-19

Merlin Bruening, University of Notre Dame

This live session talk is part of the Fundamentals/Therapeutics Live Keynote III. Prof Merlin Bruening, from the University of Notre Dame, and their group have devised a process to use membrane-based affinity to capture, elute, and quantify the concentration of COVID-19 specific antibodies. This technique could elucidate an easy way to calculate the amounts of antibodies against SARS-CoV2 in serum. 

The aim is to remove/elute antibody of interest specific to SARS-CoV2 from the mix of antibodies and proteins available in serum. To make this possible, the team uses nylon membrane and functionalizes them to capture/attract antibodies. The nylon membrane is functionalized with layer-by-layer deposition of polyelectrolytes like poly(acrylic acid) (PAA). Rinsing the membrane at low pH effects in carboxylic acid groups which can be used to then be modified with polyethyleneimine (PEI) polycations. Further after functionalization, a peptide mimotope can be added to the modified nylon which binds to specific protein regions. Preliminary data shows that when using Avastin/serum and eluting them using SDS/DTT, the resulting eluate contains pure Avastin captured and eluted. The next objective was to quantify the Avastin antibody. Avastin antibody quantitation was performed with spot blotting over PAA membrane and observing fluorescence with a secondary fluorescent-labeled antibody.

 

For calibration of the technique with COVID-19 antibodies, an anti-RBD protein is being functionalized with the membrane which showed a calibrated increase in the spot intensity of SARS-CoV2 monoclonal Antibodies. Data collected from fluorescence capturing of COVID antibodies would be helpful in analyzing if the patient has sufficient amounts of antibodies to have monoclonal antibody therapy. Further developments can yield in an efficient antibody detecting system!

 

 

Liu et al. Anal. Chem

 

 

 

 

 

 

Picture credit: Anal. Chem - Liu et al. Anal. Chem. 2018, 90, 20, 12161-12167

 

 

 

 

Following the third lecture in the session, a panel discussion was conducted. 

The panel consisted of, 

Elizabeth Wayne, Carnegie Mellon University

Kaitlyn Sadtler, National Institutes of Health

Jonathan Rivnay, Northwestern University

Merlin Bruening, University of Notre Dame

Susan Daniel, Cornell University 

Burak Ozdoganlar, Carnegie Mellon University

 

Merlin Bruening hopes that the research systems would get more opportunities and collaborations with companies that would aid in bringing out a clinical product from labs, such as quantitation of antibodies at a short time during a pandemic. Elizabeth from the panel Therapeutics section focuses on how the advances in diagnostics and therapy-based approaches to fulfill the therapeutic needs during the pandemic. 

Susan Daniel addresses suggesting that the structure-function relation is the key to figure out mechanisms to invent vaccines for new viruses like SARS-CoV2. Susan adds that viruses being non-alive particles, like small nanomachines to figure out how they work in the field. She urges on the shift of using the engineering part of nanodevices to cater the needs of viral detection engineering. Burak comments by stating that with the current lack of scalable manufacturing systems, many companies looking into using microneedle arrays to manage logistics and the pandemic need. But, difficulties in fabrication technology to cover costs and scalability makes them hard to get implemented into vaccines. 

Written by Arun Kumar. You can catch the session anytime through December 31st! Follow us on Twitter for more updates: @Arun Kumar @Materials_MRS