Attachment 1 - NIST Requirements - Amendment 1.pdf

NIST REQUIREMENTS DOCUMENT

Title: 100 nm Diameter Polystyrene Latex Nanoparticles

1. Background

The Microsystems and Nanotechnology Division of the National Institute of Standards and Technology (NIST) needs to acquire a batch of nominal 100-nm diameter polystyrene latex (PSL) bottled units which will be measured and certified as a Standard Reference Material (SRM) to replace the sold-out SRM 1963a. The Certificate of Analysis for SRM 1963a is attached as supplementary documentation, but the goal is for the new material to exceed the SRM 1963a specifications. This SRM is vital to enable and support the continued development, commercialization, and safe use of nanotechnology worldwide. This SRM is used in measurement development, quality control, preclinical research and development, instrument calibration and method/laboratory performance verification, etc.

2. Objectives

For this SRM, it is important that the size and shape of the nanoparticle spheres in the polystyrene latex (PSL) sample be as perfect and uniform as possible and that the material be shelf stable.

Important parameters include:

• Mean particle size

• Monomodal, narrow and symmetric particle size distribution, with minimal tailing

• Spheroidal shape

• Absence of aggregation

• Long-term stability

The particle size and size distribution will be certified values for the new SRM. It will also be desirable for the end-user’s benefit to know as much as possible about the solution-phase composition and the particle surface character, and to have an estimate of the particle number concentration.

3. Scope

The contractor shall deliver 150 vials of 100 nm nominal-diameter polystyrene latex, all derived from a single synthesis batch and meeting the minimum specifications as stated below.

4. Minimum Technical Specifications

1. The contractor shall deliver 150 individual vials of nominal 100 nm diameter non-functionalized PSL. Each vial shall contain a minimum of 5 mL of the latex material at a minimum concentration of 0.5 % total nanoparticle solids by mass. The vials shall be sequentially numbered in the order of filling if possible. The individual vial labels shall be removable or have no supplier-identifying information.

2. The vials and the latex shall be designed to be shelf stable for minimum of three (3) years, e.g., resistant to aggregation and microbial growth. Stronger Technical Consideration w il l be given to those offers that can demonstrate a longer period of stabil ity, up to ten (10) years.

3. The latex particles shall consist primarily of polystyrene but may contain up to 20 % copolymer by mass.

4. The contractor shall produce the PSL as a single batch, i.e., no mixing of smaller batches to obtain the target volume and concentration.

5. The PSL particles shall be monomodal and the particle size shall lie between 95 nm and 105 nm as measured by dynamic light scattering (DLS), reported as the intensity-weighted, harmonic-mean diameter, also known as the z-average diameter.

6. The relative full width at half maximum (FWHM) of the particle size distribution shall be less than or equal to 4 %. The relative full width at 5 % maximum (FW5M) shall be less than or equal to 8 %, and the distribution shall be symmetric such that at the 5 % of maximum level the distribution lies completely within ± 4 % of the modal diameter. These distribution specifications shall be determined from the analysis of a statistically representative measurement of at least 1000 individual particles, using a technique such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), or differential mobility analysis (DMA). Appropriate binning and smoothing of the raw data are permitted for the purpose of this analysis. [Note: The value of the mean or modal size as inferred from these individual particle data are not specified, i.e., not required to lie between 95 nm and 105 nm.]

7. The PSL must be singly dispersed (not aggregated); the presence of a small fraction of minor aggregates (e.g., dimers and trimers) and odd shaped (non-spheroidal) particles can be tolerated up to 1 % total by number.

8. The contractor shall provide a report of analysis (ROA) for the PSL. The ROA shall contain at a minimum the following information:

a. A plot of the size distribution and the derived FWHM and FW5M based on at least 1000 individual particle measurements using a technique such as SEM, TEM, AFM, or DMA, as described in Item 6 of these Specifications.

b. Individual particle diameter data for all the particles measured for the size distribution plot described in Item 8(a).

c. Five or more representative microscope images of roughly 10 or more particles per image showing the uniformity, morphology, and dispersion of the particles.

d. The z-average size measured by dynamic light scattering (DLS), i.e., the intensity-weighted harmonic mean diameter. DLS measurement conditions and analysis must be optimized to minimize multiple scattering and particle-particle interaction effects. At least three replicate measurements shall be reported along with measurement conditions including dilution and salt concentration.

e. A description of the composition of the latex particles, the particle surface characteristics, and the composition of the solution phase. It is understood that some of this information may be proprietary or trade secret, but whatever can be shared including solution properties such as pH and ionic strength and approximate particle number concentration would be beneficial.

At a minimum, the total suspended particle fraction and the total dissolved solids and surfactants fraction shall be provided.

f. Evidence that the PSL is sterile and/or a description of the means that have been taken to prevent microbial growth.

g. A statement regarding five-year stability expectations based on formulation, past experience with similar latexes and/or reasoned extrapolation of short-term stability data.

5. Delivery

The contractor shall deliver the materials and test reports to NIST, using FOB Destination shipping terms, within 90 days after the date of award.

The vials and reports shall be shipped to:

National Institute of Standards and Technology c/o Dr. John Kramar (Div. 681) 100 Bureau Drive, M.S. 6810 Bldg. 301/Shipping and Receiving Gaithersburg, MD 20899

6. Shipping and Packaging Requirements

Shipment shall be protected as necessary against freezing temperatures. During cold/winter months, next day or second day delivery is recommended to minimize transit time and potential issues with shipping. Including a freeze indicator in the packaging is also recommended for verifying that the materials have not been exposed to freezing conditions during shipment. Loss or damage during transit is at the risk of the supplier. NIST will not be responsible for damage or degradation during transit.

7. Inspection and Acceptance

Acceptable Quality Level The vials of PSL supplied shall conform with the associated physical and chemical properties specified in Section 4 of this NIST Requirements document and shall be suitable for use as reference materials.

If deficiencies or inconsistencies between the materials and the documentation (as defined in Section

4) are found, or if less than the stated quantity of materials are received intact, the contractor will have 30 days to correct the deficiency at no additional cost to the Government.

Monitoring Method The NIST Technical Point of Contact will verify that the received materials satisfy the conditions of the procurement. Acceptance will be based upon the delivery of 150 vials of PSL material that meet the specifications, accompanied by a report of analysis as described in Section 4, Item 8. Acceptance will be completed no later than fifteen (15) business days after receipt of the material.

8. Attachments SRM 1963a Certificate of Analysis