Tag Archives: University of Helsinki

Achieving precise control by decorating iron nanocubes with gold

A June 17,2019 news item on phys.org describes a new technique for producing nanoparticles,

One of the major challenges in nanotechnology is the precise control of shape, size and elemental composition of every single nanoparticle. Physical methods are able to produce homogeneous nanoparticles free of surface contamination. However, they offer limited opportunity to control the shape and specific composition of the nanoobjects when they are being built up.

A recent collaboration between the University of Helsinki and the Okinawa Institute of Science and Technology (OIST) Graduate University revealed that hybrid Au/Fe nanoparticles can grow in an unprecedentedly complex structure with a single-step fabrication method. Using a computational modeling framework, the groups of Professor Flyura Djurabekova at the University of Helsinki and Prof. Sowwan at OIST succeeded in deciphering the growth mechanism by a detailed multistage model.

A June 14, 2019 University of Helsinki press release (also on EurekAlert but published June 17, 2019), which originated the news item, expands on the theme,

Elegantly combined considerations of kinetic and thermodynamic effects explained the formation of embedded gold layers and the site-specific surface gold decoration. These results open up a possibility for engineering a multitude of hybrid nanoparticles for a wide range of emerging applications. Their research was recently published in the highly ranked open access journal Advanced Science.

“When nature surprises us with an unexpectedly beautiful pattern, we must recognize it and explain. This is the way to cooperate with nature that is always ready to teach and expecting us to learn,” says Dr. Junlei Zhao, a postdoctoral researcher in the group of Prof. Djurabekova.

Nowadays, scientists are able to study nano-scale phenomena with great accuracy by using high-performance computational software and modern supercomputing infrastructures. These are of great support, not only for advancing fundamental science but also for finding promising solutions for many challenges of humanity.

Here’s a link to and a citation for the paper,

Site‐Specific Wetting of Iron Nanocubes by Gold Atoms in Gas‐Phase Synthesis by Jerome Vernieres, Stephan Steinhauer, Junlei Zhao, Panagiotis Grammatikopoulos, Riccardo Ferrando, Kai Nordlund, Flyura Djurabekova, Mukhles Sowwan. Advanced Science Volume 6, Issue 13
1900447 uly 3, 2019 DOI: https://doi.org/10.1002/advs.201900447 First published online: 02 May 2019

This paper is open access.

Electrochemical measurements of biomolecules

This work comes from Finland and features some new nano shapes. From a Nov. 10, 2016 news item on phys.org,

Tomi Laurila’s research topic has many quirky names.

“Nanodiamond, nanohorn, nano-onion…,” lists off the Aalto University Professor, recounting the many nano-shapes of carbon. Laurila is using these shapes to build new materials: tiny sensors, only a few hundred nanometres across, that can achieve great things due to their special characteristics.

For one, the sensors can be used to enhance the treatment of neurological conditions. That is why Laurila, University of Helsinki Professor Tomi Taira and experts from HUS (the Hospital District of Helsinki and Uusimaa) are looking for ways to use the sensors for taking electrochemical measurements of biomolecules. Biomolecules are e.g. neurotransmitters such as glutamate, dopamine and opioids, which are used by nerve cells to communicate with each other.

A Nov. 10, 2016 Aalto University press release, which originated the news item, expands on the theme,

Most of the drugs meant for treating neurological diseases change the communication between nerve cells that is based on neurotransmitters. If we had real time and individual information on the operation of the neurotransmitter system, it would make it much easier to for example plan precise treatments’, explains Taira.

Due to their small size, carbon sensors can be taken directly next to a nerve cell, where the sensors will report what kind of neurotransmitter the cell is emitting and what kind of reaction it is inducing in other cells.

‘In practice, we are measuring the electrons that are moving in oxidation and reduction reactions’, Laurila explains the operating principle of the sensors.

‘The advantage of the sensors developed by Tomi and the others is their speed and small size. The probes used in current measurement methods can be compared to logs on a cellular scale – it’s impossible to use them and get an idea of the brain’s dynamic’, summarizes Taira.

Feedback system and memory traces

For the sensors, the journey from in vitro tests conducted in glass dishes and test tubes to in vivo tests and clinical use is long. However, the researchers are highly motivated.

‘About 165 million people are suffering from various neurological diseases in Europe alone. And because they are so expensive to treat, neurological diseases make up as much as 80 per cent of health care costs’, tells Taira.

Tomi Laurila believes that carbon sensors will have applications in fields such as optogenetics. Optogenetics is a recently developed method where a light-sensitive molecule is brought into a nerve cell so that the cell’s electric operation can then be turned on or off by stimulating it with light. A few years ago, a group of scientists proved in the scientific journal Nature that they had managed to use optogenetics to activate a memory trace that had been created previously due to learning. Using the same technique, researchers were able to demonstrate that with a certain type of Alzheimer’s, the problem is not that there are no memory traces being created, but that the brain cannot read the traces.

‘So the traces exist, and they can be activated by boosting them with light stimuli’, explains Taira but stresses that a clinical application is not yet a reality. However, clinical applications for other conditions may be closer by. One example is Parkinson’s disease. In Parkinson’s disease, the amount of dopamine starts to decrease in the cells of a particular brain section, which causes the typical symptoms such as tremors, rigidity and slowness of movement. With the sensors, the level of dopamine could be monitored in real time.

‘A sort of feedback system could be connected to it, so that it would react by giving an electric or optical stimulus to the cells, which would in turn release more dopamine’, envisions Taira.

‘Another application that would have an immediate clinical use is monitoring unconscious and comatose patients. With these patients, the level of glutamate fluctuates very much, and too much glutamate damages the nerve cell – online monitoring would therefore improve their treatment significantly.

Atom by atom

Manufacturing carbon sensors is definitely not a mass production process; it is slow and meticulous handiwork.

‘At this stage, the sensors are practically being built atom by atom’, summarises Tomi Laurila.

‘Luckily, we have many experts on carbon materials of our own. For example, the nanobuds of Professor Esko Kauppinen and the carbon films of Professor Jari Koskinen help with the manufacturing of the sensors. Carbon-based materials are mainly very compatible with the human body, but there is still little information about them. That’s why a big part of the work is to go through the electrochemical characterisation that has been done on different forms of carbon.’

The sensors are being developed and tested by experts from various fields, such as chemistry, materials science, modelling, medicine and imaging. Twenty or so articles have been published on the basic properties of the materials. Now, the challenge is to build them into geometries that are functional in a physiological environment. And taking measurements is not simple, either.

‘Brain tissue is delicate and doesn’t appreciate having objects being inserted in it. But if this were easy, someone would’ve already done it’, conclude the two.

I wish the researchers good luck.

Sustainable Nanotechnologies (SUN) project draws to a close in March 2017

Two Oct. 31, 2016 news item on Nanowerk signal the impending sunset date for the European Union’s Sustainable Nanotechnologies (SUN) project. The first Oct. 31, 2016 news item on Nanowerk describes the projects latest achievements,

The results from the 3rd SUN annual meeting showed great advancement of the project. The meeting was held in Edinburgh, Scotland, UK on 4-5 October 2016 where the project partners presented the results obtained during the second reporting period of the project.

SUN is a three and a half year EU project, running from 2013 to 2017, with a budget of about €14 million. Its main goal is to evaluate the risks along the supply chain of engineered nanomaterials and incorporate the results into tools and guidelines for sustainable manufacturing.

The ultimate goal of the SUN Project is the development of an online software Decision Support System – SUNDS – aimed at estimating and managing occupational, consumer, environmental and public health risks from nanomaterials in real industrial products along their lifecycles. The SUNDS beta prototype has been released last October, 2015, and since then the main focus has been on refining the methodologies and testing them on selected case studies i.e. nano-copper oxide based wood preserving paint and nano- sized colourants for plastic car part: organic pigment and carbon black. Obtained results and open issues were discussed during the third annual meeting in order collect feedbacks from the consortium that will inform, in the next months, the implementation of the final version of the SUNDS software system, due by March 2017.

An Oct. 27, 2016 SUN project press release, which originated the news item, adds more information,

Significant interest has been payed towards the results obtained in WP2 (Lifecycle Thinking) which main objectives are to assess the environmental impacts arising from each life cycle stage of the SUN case studies (i.e. Nano-WC-Cobalt (Tungsten Carbide-cobalt) sintered ceramics, Nanocopper wood preservatives, Carbon Nano Tube (CNT) in plastics, Silicon Dioxide (SiO2) as food additive, Nano-Titanium Dioxide (TiO2) air filter system, Organic pigment in plastics and Nanosilver (Ag) in textiles), and compare them to conventional products with similar uses and functionality, in order to develop and validate criteria and guiding principles for green nano-manufacturing. Specifically, the consortium partner COLOROBBIA CONSULTING S.r.l. expressed its willingness to exploit the results obtained from the life cycle assessment analysis related to nanoTiO2 in their industrial applications.

On 6th October [2016], the discussions about the SUNDS advancement continued during a Stakeholder Workshop, where representatives from industry, regulatory and insurance sectors shared their feedback on the use of the decision support system. The recommendations collected during the workshop will be used for the further refinement and implemented in the final version of the software which will be released by March 2017.

The second Oct. 31, 2016 news item on Nanowerk led me to this Oct. 27, 2016 SUN project press release about the activities in the upcoming final months,

The project has designed its final events to serve as an effective platform to communicate the main results achieved in its course within the Nanosafety community and bridge them to a wider audience addressing the emerging risks of Key Enabling Technologies (KETs).

The series of events include the New Tools and Approaches for Nanomaterial Safety Assessment: A joint conference organized by NANOSOLUTIONS, SUN, NanoMILE, GUIDEnano and eNanoMapper to be held on 7 – 9 February 2017 in Malaga, Spain, the SUN-CaLIBRAte Stakeholders workshop to be held on 28 February – 1 March 2017 in Venice, Italy and the SRA Policy Forum: Risk Governance for Key Enabling Technologies to be held on 1- 3 March in Venice, Italy.

Jointly organized by the Society for Risk Analysis (SRA) and the SUN Project, the SRA Policy Forum will address current efforts put towards refining the risk governance of emerging technologies through the integration of traditional risk analytic tools alongside considerations of social and economic concerns. The parallel sessions will be organized in 4 tracks:  Risk analysis of engineered nanomaterials along product lifecycle, Risks and benefits of emerging technologies used in medical applications, Challenges of governing SynBio and Biotech, and Methods and tools for risk governance.

The SRA Policy Forum has announced its speakers and preliminary Programme. Confirmed speakers include:

  • Keld Alstrup Jensen (National Research Centre for the Working Environment, Denmark)
  • Elke Anklam (European Commission, Belgium)
  • Adam Arkin (University of California, Berkeley, USA)
  • Phil Demokritou (Harvard University, USA)
  • Gerard Escher (École polytechnique fédérale de Lausanne, Switzerland)
  • Lisa Friedersdor (National Nanotechnology Initiative, USA)
  • James Lambert (President, Society for Risk Analysis, USA)
  • Andre Nel (The University of California, Los Angeles, USA)
  • Bernd Nowack (EMPA, Switzerland)
  • Ortwin Renn (University of Stuttgart, Germany)
  • Vicki Stone (Heriot-Watt University, UK)
  • Theo Vermeire (National Institute for Public Health and the Environment (RIVM), Netherlands)
  • Tom van Teunenbroek (Ministry of Infrastructure and Environment, The Netherlands)
  • Wendel Wohlleben (BASF, Germany)

The New Tools and Approaches for Nanomaterial Safety Assessment (NMSA) conference aims at presenting the main results achieved in the course of the organizing projects fostering a discussion about their impact in the nanosafety field and possibilities for future research programmes.  The conference welcomes consortium partners, as well as representatives from other EU projects, industry, government, civil society and media. Accordingly, the conference topics include: Hazard assessment along the life cycle of nano-enabled products, Exposure assessment along the life cycle of nano-enabled products, Risk assessment & management, Systems biology approaches in nanosafety, Categorization & grouping of nanomaterials, Nanosafety infrastructure, Safe by design. The NMSA conference key note speakers include:

  • Harri Alenius (University of Helsinki, Finland,)
  • Antonio Marcomini (Ca’ Foscari University of Venice, Italy)
  • Wendel Wohlleben (BASF, Germany)
  • Danail Hristozov (Ca’ Foscari University of Venice, Italy)
  • Eva Valsami-Jones (University of Birmingham, UK)
  • Socorro Vázquez-Campos (LEITAT Technolоgical Center, Spain)
  • Barry Hardy (Douglas Connect GmbH, Switzerland)
  • Egon Willighagen (Maastricht University, Netherlands)
  • Nina Jeliazkova (IDEAconsult Ltd., Bulgaria)
  • Haralambos Sarimveis (The National Technical University of Athens, Greece)

During the SUN-caLIBRAte Stakeholder workshop the final version of the SUN user-friendly, software-based Decision Support System (SUNDS) for managing the environmental, economic and social impacts of nanotechnologies will be presented and discussed with its end users: industries, regulators and insurance sector representatives. The results from the discussion will be used as a foundation of the development of the caLIBRAte’s Risk Governance framework for assessment and management of human and environmental risks of MN and MN-enabled products.

The SRA Policy Forum: Risk Governance for Key Enabling Technologies and the New Tools and Approaches for Nanomaterial Safety Assessment conference are now open for registration. Abstracts for the SRA Policy Forum can be submitted till 15th November 2016.
For further information go to:

There you have it.

Silver nanoparticles, water, the environment, and toxicity

I am contrasting two very different studies on silver nanoparticles in water and their effect on the environment to highlight the complex nature of determining the risks and environmental effects associated with nanoparticles in general. One piece of research suggests that silver nanoparticles are less dangerous than other commonly used forms of silver while the other piece raises some serious concerns.

A Feb. 28, 2013 news item on Nanowerk features research about the effects that silver nanoparticles have on aquatic ecosystems (Note: A link has been removed),

According to Finnish-Estonian joint research with data obtained on two crustacean species, there is apparently no reason to consider silver nanoparticles more dangerous for aquatic ecosystems than silver ions.

The results were reported in the journal Environmental Science and Pollution Research late last year (“Toxicity of two types of silver nanoparticles to aquatic crustaceans Daphnia magna and Thamnocephalus platyurus”). Jukka Niskanen has utilised the same polymerisation and coupling reactions in his doctoral dissertation studying several hybrid nanomaterials, i.e. combinations of synthetic polymers and inorganic (gold, silver and montmorillonite) nanoparticles. Niskanen will defend his doctoral thesis at the University of Helsinki in April.

The University of Helsikinki Feb. 28, 2013 press release written by Minna Merilainen and which originated the new item provides details about the research,

“Due to the fact that silver in nanoparticle form is bactericidal and also fungicidal and also prevents the reproduction of those organisms, it is now used in various consumer goods ranging from wound dressing products to sportswear,” says Jukka Niskanen from the Laboratory of Polymer Chemistry at the University of Helsinki, Finland.A joint study from the University of Helsinki and the National Institute of Chemical Physics and Biophysics (Tallinn, Estonia), Toxicity of two types of silver nanoparticles to aquatic crustaceans Daphnia magna and Thamnocephalus platyurus, shows that silver nanoparticles are apparently no more hazardous to aquatic ecosystems than a water-soluble silver salt. The study compared the ecotoxicity of silver nanoparticles and a water-soluble silver salt.

“Our conclusion was that the environmental risks caused by silver nanoparticles are seemingly not higher than those caused by a silver salt. However, more research is required to reach a clear understanding of the safety of silver-containing particles,” Niskanen says.

Indeed, silver nanoparticles were found to be ten times less toxic than the soluble silver nitrate - a soluble silver salt used for the comparison.

The bioavailability of silver varies in different test media

To explain this phenomenon, the researchers refer to the variance in the bioavailability of silver to crustaceans in different tested media.

University lecturer Olli-Pekka Penttinen from the Department of Environmental Sciences of the University of Helsinki goes on to note that the inorganic and organic compounds dissolved in natural waters (such as humus), water hardness and sulfides have a definite impact on the bioavailability of silver. Due to this, the toxicity of both types of tested nanoparticles and the silver nitrate measured in the course of the study was lower in natural water than in artificial fresh water.

The toxicity of silver nanoparticles and silver ions was studied using two aquatic crustaceans, a water flea (Daphnia magna) and a fairy shrimp ( Thamnocephalus platyurus). Commercially available protein-stabilised particles and particles coated with a water-soluble, non-toxic polymer, specifically synthesised for the purpose, were used in the study. First, the polymers were produced utilising a controlled radical polymerization method. Synthetic polymer-grafted silver particles were then produced by attaching the water-soluble polymer to the surface of the silver with a sulfur bond.

Jukka Niskanen has utilised such polymerisation and coupling reactions in his doctoral dissertation. Polymeric and hybrid materials: polymers on particle surfaces and air-water interfaces, studying several hybrid nanomaterials , i.e., combinations of synthetic polymers and inorganic (gold, silver and montmorillonite) nanoparticles....

It was previously known from other studies and research results that silver changes the functioning of proteins and enzymes. It has also been shown that silver ions can prevent the replication of DNA. Concerning silver nanoparticles, tests conducted on various species of bacteria and fungi have indicated that their toxicity varies. For example, gram-negative bacteria such as Escherichia coli are more sensitive to silver nanoparticles than gram-positive ones (such as Staphylococcus aureus). The difference in sensitivity is caused by the structural differences of the cell membranes of the bacteria. The cellular toxicity of silver nanoparticles in mammals has been studied as well. It has been suggested that silver nanoparticles enter cells via endocytosis and then function in the same manner as in bacterial cells, damaging DNA and hindering cell respiration. Electron microscope studies have shown that human skin is permeable to silver nanoparticles and that the permeability of damaged skin is up to four times higher than that of healthy skin.

While this Finnish-Estonian study suggests that silver nanoparticles do not have a negative impact on the tested crustaceans in an aquatic environment, there’s a study from Duke University suggests that silver nanoparticles in wastewater which is later put to agricultural use may cause problems. From the Feb. 27, 2013 news release on EurekAlert,

In experiments mimicking a natural environment, Duke University researchers have demonstrated that the silver nanoparticles used in many consumer products can have an adverse effect on plants and microorganisms.

The main route by which these particles enter the environment is as a by-product of water and sewage treatment plants. [emphasis] The nanoparticles are too small to be filtered out, so they and other materials end up in the resulting “sludge,” which is then spread on the land surface as a fertilizer.

The researchers found that one of the plants studied, a common annual grass known as Microstegium vimeneum, had 32 percent less biomass in the mesocosms treated with the nanoparticles. Microbes were also affected by the nanoparticles, Colman [Benjamin Colman, a post-doctoral fellow in Duke’s biology department and a member of the Center for the Environmental Implications of Nanotechnology (CEINT)] said. One enzyme associated with helping microbes deal with external stresses was 52 percent less active, while another enzyme that helps regulate processes within the cell was 27 percent less active. The overall biomass of the microbes was also 35 percent lower, he said.

“Our field studies show adverse responses of plants and microorganisms following a single low dose of silver nanoparticles applied by a sewage biosolid,” Colman said. “An estimated 60 percent of the average 5.6 million tons of biosolids produced each year is applied to the land for various reasons, and this practice represents an important and understudied route of exposure of natural ecosystems to engineered nanoparticles.”

“Our results show that silver nanoparticles in the biosolids, added at concentrations that would be expected, caused ecosystem-level impacts,” Colman said. “Specifically, the nanoparticles led to an increase in nitrous oxide fluxes, changes in microbial community composition, biomass, and extracellular enzyme activity, as well as species-specific effects on the above-ground vegetation.”

As previously noted, these two studies show just how complex the questions of risk and nanoparticles can become.  You can find out more about the Finish-Estonian study,

Toxicity of two types of silver nanoparticles to aquatic crustaceans Daphnia magna and Thamnocephalus platyurus by  Irina Blinova, Jukka Niskanen, Paula Kajankari, Liina Kanarbik, Aleksandr Käkinen, Heikki Tenhu, Olli-Pekka Penttinen, and Anne Kahru. Environmental Science and Pollution Research published November 11, 2012 online

The publisher offers an interesting option for this article. While it is behind a paywall, access is permitted through a temporary window if you want to preview a portion of the article that lies beyond the abstract.

Meanwhile here’s the article by the Duke researchers,

Low Concentrations of Silver Nanoparticles in Biosolids Cause Adverse Ecosystem Responses under Realistic Field Scenario by Benjamin P. Colman, Christina L. Arnaout, Sarah Anciaux, Claudia K. Gunsch, Michael F. Hochella Jr, Bojeong Kim, Gregory V. Lowry,  Bonnie M. McGill, Brian C. Reinsch, Curtis J. Richardson, Jason M. Unrine, Justin P. Wright, Liyan Yin, and Emily S. Bernhardt. PLoS ONE 2013; 8 (2): e57189 DOI: 10.1371/journal.pone.0057189

This article is open access as are all articles published by the Public Library of Science (PLoS) journals.

For anyone interested in the Duke University/CEINT mesocosm project, I made mention of it in an Aug. 15, 2011 posting.