ISO/TS 20660:2019

Nanotechnologies — Antibacterial silver nanoparticles — Specification of characteristics and measurement methods

This document provides guidance for the specification of characteristics and relevant measurement methods for silver nanoparticles in powder or colloidal forms that are intended for antibacterial applications in nanotechnology. This document is intended to aid the producer in providing the physicochemical characteristics of silver nanoparticles that have an antibacterial effect to the buyer. This document does not cover considerations specific to health and safety issues either during manufacturing or use.

Nanotechnologies — Nanoparticules d'argent antibactériennes — Spécification des caractéristiques et des méthodes de mesure

General Information

• Status: Published
• Publication Date: 02-Jun-2019
• ICS: 07.120 - Nanotechnologies
• Technical Committee: ISO/TC 229 - Nanotechnologies
• Drafting Committee: ISO/TC 229 - Nanotechnologies
• Current Stage: 9092 - International Standard to be revised
• Completion Date: 15-Oct-2024

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 20660
First edition
2019-06
Nanotechnologies — Antibacterial
silver nanoparticles — Specification
of characteristics and measurement
methods
Nanotechnologies — Nanoparticules d'argent antibactériennes —
Spécification des caractéristiques et des méthodes de mesure
Reference number
©
ISO 2019
© ISO 2019
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ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviations . 2
5 Characteristics and measurement methods . 3
5.1 General . 3
5.2 Average size and size distribution of primary particles . 4
5.3 Zeta potential . 4
5.4 Specific surface area . 4
5.5 Total silver content . 4
5.6 Hydrodynamic size . 5
5.7 Silver nanoparticle number concentration. 5
6 Sampling . 5
7 Test report . 5
Annex A (informative) Measurement methods for antibacterial silver nanoparticles .6
Annex B (informative) Relationship between silver nanoparticle characteristics and
antibacterial performance . 8
Annex C (informative) Antibacterial performance test.10
Bibliography .11
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
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.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 229, Nanotechnologies.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved

Introduction
Silver nanoparticles have become one of the most widely utilized nanomaterials in consumer products
for their antibacterial properties. The application of silver nanoparticles is increasingly being adopted
in consumer products to control the growth of microorganisms on the surfaces or interiors of products.
When silver nanoparticles interact with microorganisms silver ions are released, and these ions may
affect and damage microorganisms in different ways. However, the mechanism behind the bactericidal
[1]
effect is not well known . There have been several possible mechanisms proposed in the scientific
literature: 1) silver ions with positive electricity released from silver nanoparticles are able to rapidly
bind to sulfhydryl groups on the surfaces of bacteria, which leads the structures of bacteria to change
and become damaged, 2) the uptake of silver ions or small nanoparticles disrupts adenosine triphosphate
production and DNA replication, and 3) silver nanoparticles and ions generate reactive oxygen species
[2]-[4]
resulting in oxidative damage . Other scientific evidence of the antibacterial performance of silver
nanoparticle is listed in Annex B. The antibacterial properties of silver nanoparticles are related to
their physicochemical characteristics.
Although antibacterial products that utilize silver nanoparticle are widely distributed in the
market, most of these products are sold without providing information on the physicochemical and
corresponding antibacterial characteristics of nanoparticles. Currently, most manufacturers provide
specifications based on their own practices.
This document provides guidance for the specification of characteristics and relevant recommended
measurement methods, referenced from other standards for silver nanoparticles in powder and colloidal
forms that are intended for antibacterial applications in nanotechnology. The major measurement
methods available to industry for the determination of parameters specified in this document are of
course recommended in the specification. This document reviews selected measurement methods that
are commonly used at present, and therefore will require updating on a regular basis.
TECHNICAL SPECIFICATION ISO/TS 20660:2019(E)
Nanotechnologies — Antibacterial silver nanoparticles —
Specification of characteristics and measurement methods
1 Scope
This document provides guidance for the specification of characteristics and relevant measurement
methods for silver nanoparticles in powder or colloidal forms that are intended for antibacterial
applications in nanotechnology.
This document is intended to aid the producer in providing the physicochemical characteristics of silver
nanoparticles that have an antibacterial effect to the buyer.
This document does not cover considerations specific to health and safety issues either during
manufacturing or use.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the cited edition applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 26824, Particle characterization of particulate systems — Vocabulary
ISO/TS 80004-1, Nanotechnologies — Vocabulary — Part 1: Core terms
ISO/TS 80004-2, Nanotechnologies — Vocabulary — Part 2: Nano-objects
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 26824, ISO/TS 80004-1, ISO/
TS 80004-2 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
silver nanoparticle
nanoparticle composed of silver with all three external dimensions in the nanoscale
[SOURCE: modified from ISO/TS 80004-2, 4.1, modified]
3.2
primary particle
Original source particle (3.1) of agglomerates (3.4) or aggregates (3.5) or mixtures of the two
Note 1 to entry: Constituent particles (3.3) of agglomerates or aggregates at a certain actual state may be primary
particles, but often the constituents are aggregates.
Note 2 to entry: Agglomerates and aggregates are also termed secondary particles.
[SOURCE: ISO 26824, 1.4]
3.3
nanoscale
size range from approximately 1 nm to 100 nm
Note 1 to entry: Properties that are not extrapolations from a larger size are predominantly exhibited in this
length range.
[SOURCE: ISO/TS 80004-1, 2.1]
3.4
agglomerate
collection of weakly or medium strongly bound particles (3.1) where the resulting external surface area
is similar to the sum of the surface areas of the individual components
Note 1 to entry: The forces holding agglomerate together are weak forces, for example van der Waals forces or
simple physical entanglement.
Note 2 to entry: Agglomerates are also termed secondary particles and the original source particles are termed
primary particles (3.2).
[SOURCE: ISO 26824, 1.2]
3.5
aggregate
particle (3.1) comprising strongly bonded or fused particles where the resulting external surface area
is significantly smaller than the sum of surface areas of the individual components
Note 1 to entry: The forces holding an aggregate together are strong forces, for example covalent bonds, or those
resulting from sintering or complex physical entanglement, or otherwise combined former primary particles.
Note 2 to entry: Aggregates are also termed secondary particles and the original source particles are termed
primary particles (3.2).
[SOURCE: ISO 26824, 1.3]
3.6
antibacterial activity
property of substances or phenomena that kills (bactericidal) or slow down (bacteriostatic) the growth
of bacteria
4 Symbols and abbreviations
For the purposes of this document, the following symbols and abbreviations apply:
Abbreviation Meaning
AAS Atomic absorption spectrometry
AgNP Silver nanoparticle
BET Brunauer-Emmett-Teller
DLS Dymanic light scattering
ELS Electrophoretic light scattering
ICP-MS Inductively coupled plasma mass spectrometry
ICP-OES Inductively coupled plasma optical emission spectrometry
NP Nanoparticle
PTA Particle tracking analysis
SAXS Small angle X-ray scattering
2 © ISO 2019 – All rights reserved

SEM Scanning electron microscopy
spICP-MS Single particle inductively coupled plasma mass spectrometry
TEM Tranmission electron microscopy
5 Characteristics and measurement methods
5.1 General
The specification of characteristics and measurement methods for antibacterial silver nanoparticles is
separated into two categories: those that are essential are listed in Table 1 and those that are additional
are listed in Table 2. A producer of antibacterial silver nanoparticles shall measure the characteristics
in Table 1 and should also measure the characteristics in Table 2 and report the results to the buyer of
AgNPs. In Tables 1 and 2, guidance for the measurement met
...