Issue 1 - Thermo Fisher

Cell Culture
Testing the efficacy of the antimicrobial
treatment – a study
ELGA LabWater–Water quality standards
for Research and analysis applications
Advancing
LCP Research Group, Thermo Fisher Scientific, Vantaa, Finland
Type 1+ – Goes beyond the purity requirements
of Type 1 water’
Microbes, such as bacteria, fungi and algae, are found
everywhere around us, and they are also present in the
human skin. Normally they are not harmful, but in some
cases they may cause deterioration of the material
they grow on or cause cross contamination. Even
when strict cleanliness is observed, microbes from
the hands may contaminate any surface. Antimicrobial
treatment protects from microbial growth and adds
additional protection against cross- contamination.
i.e. bacteria from a pipette that could contaminate the
sample.
How does it work?
The active ingredient of the antimicrobial material
tested is silver in the form of silver ions. In a humid
environment the ions are slowly released from the
inorganic matrix via an ion-exchange mechanism.
The release is slow, but fast enough to maintain an
effective concentration on the surface of the material.
Silver ions are taken up by microbial cells and interrupt
critical functions, such as DNA replication, resulting
in the death of the microbes. The antimicrobial effect
of the material used is longterm and silver inhibits the
growth of a broad spectrum of microorganisms.
Testing the efficacy of the antimicrobial treatment
The antimicrobial effect of the material was evaluated
according to ASTM standard E21 80. The standard
describes a test method to evaluate (quantitatively) the
antimicrobial effectiveness of agents incorporated or
bound into or onto mainly flat hydrophobic or polymeric
surfaces. The test organisms used were Escherichia
coli, Staphylococcus aureus, Candida albicans and
conidiospores of Aspergillus niger.
Contamination of the antimicrobial polymer pieces
(from a Thermo Scientific Finnpipette F1 - The handle
and the dispensing button are made of an antimicrobial
polymer) was carried out by pipetting 0.2 ml of the
cell or conidiospore suspension on test pieces that
were stored in a horizontal position throughout
the experiments. After complete drying of the
suspensions, the amount of colony forming units (cfu,
a measure for viable cells) was determined after 4
hours and after 24 hours.
After 4 hours, a reduction of cfu was seen for all four
test organisms. After 24 hours, the reduction was
improved for each microorganism, except in those
cases where 100% reduction was already achieved at
the 4 hour mark, see Figure 1.
These results show that the antimicrobial material
results in a significant reduction of microorganisms,
demonstrating the efficacy of the antimicrobial
polymer.
Please note: The antimicrobial treatment does not
remove dirt and does not protect users or others
against bacteria, viruses or other disease organisms.
Figure 1. Reduction of model microorganisms on an
antimicrobial polymer. The colony forming units were
determined at 4 and 24 hours after inoculation
Scientists perform a vast range of
applications in many different kinds
of laboratories. Therefore, different
grades of water must be purified
and utilised to match the required
procedures or appliances. Water is
one of the major components in many
applications, but the significance of
its purity is often not recognised.
In this section we highlight some common applications
and provide guidance on the water quality required.
We also provide some guidance on what purification
technologies you should be looking for in your water
system. There are many water quality standards
published throughout the world, however only a few
are relevant to specific research applications. This has
resulted in the majority of water purification companies,
including ELGA, adopting broad generic classifications
defined by measurable physical and chemical limits.
Throughout this application note we will refer to the
“Types” of water referred to in this chart (see right).
Type I – Often referred to as ultra pure, this grade is
required for some of the most water-critical
applications such as HPLC (High Performance Liquid
Chromatography) mobile phase preparation, as well
as, blanks and sample dilution for other key analytical
techniques; such as GC (Gas Chromatography),
AAS (Atomic Absorption Spectrophotometry)
and ICP-MS (Inductively Coupled Plasma Mass
Spectrometry). Type I is also required for molecular
biology applications as well as mammalian cell
culture and IVF (In vitro Fertilisation).
Type II – Is the grade for general laboratory
applications. This may include media preparation,
pH solutions and buffers and for certain clinical
analysers. It is also common for Type II systems
to be used as a feed to a Type I system*.
Type II+ – Is the grade for general laboratory
applications requiring higher inorganic purity.
Type III – Is the grade recommended for
non-critical work which may include glassware
rinsing, water baths, autoclave and disinfector
feed as well as environmental chambers and
plant growth rooms. These systems can also be
used to feed Type I systems*
Resitivity TOC(PPB) Bacteria Endotoxins
(MΩ-cm)
(EU/ml)
Type I+ 18.2