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Corning® Assay Surfaces:
NBS™ Coated Surface

  NBS Surface

Figure 1. PEO chains immobilized on polystyrene create the nonionic hydrophilic NBSTM surface that minimizes molecular binding.  

Some assays and procedures require a surface that is nonbinding because many proteins, enzymes in particular, may become activated or inactivated upon attachment to a surface. Corning's unique NBS™ treatment creates a nonionic hydrophilic surface (polyethylene oxide [PEO]-like) that minimizes molecular interactions (Figure 1). Since proteins and other biomolecules passively adsorb to surfaces primarily through hydrophobic and ionic interactions, the NBSTM surface lacking these characteristics naturally inhibits nonspecific immobilization via these forces.

Results (Table 1, below) show the NBS surface has the ability to significantly reduce (<2 ng/cm2) protein and nucleic acid binding to microplates, while maintaining enzyme activity. The nonionic, hydrophilic NBS surface is therefore well suited for enhancement of signal-to-noise in homogeneous assays such as Scintillation Proximity Assay (SPA)1. NBS surfaces are stable to aqueous biological fluids and biological reagents containing up to 20% isopropyl alcohol or DMSO or 10 M urea or 1% SDS, and over a pH range (3-11).

Table 1. Comparison of protein and nucleic acid binding with various polymers

Binding in ng/cm2





32P-l phageDNA 

Polystyrene (PS) 400 450 310 22 6
Polypropylene 380 440 370 3 <2
NBS on PS  <2.5 <2.5 5 <2 <2
Based on radiolabel assay using 100 µL/well in 96 well microplates. Contents were aspirated and washed 3 times with 200 µL/well of PBS, pH 7.4 (Ref 1). 

NBSTM Surface Properties  

Applications Homogeneous Assays, especially Scintillation Proximity Assay (SPA).  Enhances signal to noise ratio.  White, white/clear bottom, black, black/clear bottom and clear plates for luminescence, fluorescence and absorbance applications.
# Reactive Sites Not Applicable
Binding Interaction  Non-ionic hydrophilic surface
Sample Properties Ability to reduce significantly (<2 ng/cm²) protein and nucleic acid binding to polymers, maintain enzyme activity, and inhibit adhesion of a number of cell lines.
Surface/Sample Preparation No preparation required.  The surfaces have been shown to be non-cytotoxic.
Blocking Feasibilty & Method    Not Applicable. Surfaces are stable to aqueous biological fluids and to biological reagents containing up to 20% IPA and DMSO, 10 M urea, 1% SDS, pH 3-11.
Performance Criteria  Must demonstrate at least 95% reduction of non-specific binding of protein when compared to polystyrene.



1. Scintillation Proximity Assay (SPA) as described by Amersham Biosciences, now part of GELifesciences.com

Other Microplate Surfaces

Helpful Information

 Medium Binding (Untreated) Polystyrene
 High Binding Modified Polystyrene
 Aminated Modified Polystyrene
 DNA-BIND® Modified Polystyrene
 Sulfhydryl-BIND™ Modified Polystyrene
 Carbo-BIND™ Modified Polystyrene
 Universal-BIND™ Modified Polystyrene

 Nonbinding Surface (NBS™) Microplates
 Assay Surface References
 Assay Surfaces Document Library
 Microplate Surface Selection Chart
 Equipment Compatibility Guide
 Request a Sample


Available Products (Catalog)

 All NBS™ Coated Polystyrene Products