ONCYTE® AVID Porous Nitrocellulose Film Slides — Colorimetric, Chemiluminescent & Fluorescence Detection

Nitrocellulose is widely used for protein microarrays because it provides high protein-binding capacity and can support sensitive detection of proteins immobilized on the array. Grace Bio-Labs developed thin porous nitrocellulose films on glass specifically for microarray applications and reports that these films can bind substantially more protein than conventional two-dimensional surfaces. The porous structure provides a large available surface area for protein binding and can enhance fluorescence sensitivity through coherent backscatter/Tyndall-effect light scattering. These properties make nitrocellulose particularly useful for applications such as protein microarrays, antibody capture arrays, antigen arrays, and reverse-phase protein arrays.

Yes. ONCYTE film slides are compatible with fluorescence detection, including visible and near-infrared fluorescence methods. Grace Bio-Labs specifically lists fluorescence as a preferred detection method for ONCYTE NOVA, SuperNOVA, and ONYX, while its product guide states that all detection methods are compatible with ONCYTE nitrocellulose film slides.

Fluorescence is particularly useful for protein microarrays because it enables sensitive detection and multiplexing with multiple fluorophores. Grace Bio-Labs describes fluorescence as a frequently used detection method for proteins bound to nitrocellulose films.

Porous nitrocellulose can have intrinsic fluorescence, particularly at shorter visible wavelengths, so the choice of fluorophore and detection wavelength is important. Grace Bio-Labs reports that porous nitrocellulose has inherent fluorescence in the shorter wavelength range, approximately 488–594 nm emission, which can contribute to background signal.

However, Grace Bio-Labs reports that near-infrared (NIR) fluorescence detection can substantially reduce the background associated with porous nitrocellulose. In comparisons of visible and NIR detection, the reported signal-to-noise ratio in the NIR range was 1.5–3 times higher, with background levels approaching those of glass.

For example, Grace Bio-Labs demonstrated fluorescence detection of cell lysates printed on ONCYTE SuperNOVA using Alexa Fluor 647, IRDye 680, and IRDye 800. The study found substantially lower fluorescence background with NIR detection compared with 635 nm visible-range detection.

Grace Bio-Labs' selection guide identifies:

• NOVA: preferred for fluorescence; 5–6 log dynamic range
• SuperNOVA: preferred for fluorescence; 7+ log dynamic range
• ONYX: preferred for fluorescence; 4–5 log dynamic range
• AVID: preferred for colorimetric and chemiluminescent detection, although fluorescence is also compatible

For fluorescence-based protein microarrays requiring the widest specified dynamic range, SuperNOVA is the strongest choice. For general fluorescence applications, NOVA provides a 5–6 log dynamic range.

Porous and non-porous nitrocellulose slides differ primarily in their film structure, protein-binding capacity, thickness, and optical properties. Porous nitrocellulose contains a microporous structure that provides a large available surface area for protein binding, while non-porous nitrocellulose has a continuous film structure with substantially less available internal surface area.

Grace Bio-Labs' ONCYTE porous nitrocellulose films are designed to provide high protein-binding capacity. The pores provide a large surface area for binding and promote controlled, uniform wetting for microarray deposition. The porous structure can also enhance fluorescence sensitivity through light scattering within the film, known as the Tyndall effect.

Grace Bio-Labs also offers ONCYTE ONYX, a non-porous nitrocellulose film. Both porous and non-porous substrates can be used for protein microarray applications, but their performance characteristics differ. For applications requiring high protein-binding capacity, porous nitrocellulose is particularly well suited.

ONCYTE SuperNOVA is a strong choice for fluorescence-based RPPA when a very broad quantitative dynamic range is important. Grace Bio-Labs specifies a 7+ log fluorescence dynamic range for SuperNOVA, compared with 5–6 log for AVID and NOVA.

However, ONCYTE AVID is also well established for RPPA applications. Grace Bio-Labs has specifically demonstrated RPPA workflows using ONCYTE AVID, including total-protein quantitation using Fast Green and near-infrared detection.

Porous nitrocellulose is particularly useful for RPPA because of its high protein-binding capacity. Grace Bio-Labs reports a protein-binding capacity of approximately 40 µg/cm² for porous nitrocellulose and describes this high capacity as advantageous for detecting low-abundance proteins in complex tissue lysates.

If you are developing a new fluorescence-based RPPA assay and want the widest specified dynamic range, SuperNOVA is an excellent starting point. If you are using an established AVID-based RPPA workflow, AVID is also a well-supported choice.

AVID is the right choice when your laboratory uses multiple detection platforms or when you need colorimetric or chemiluminescent detection compatibility. If you are running exclusively fluorescence-based assays and do not need multi-method flexibility, NOVA offers a slightly thinner 7 µm film that provides equivalent sensitivity with more controlled wetting behavior. AVID's 12 µm film and 80° contact angle deliver the highest hydrophobicity in the ONCYTE® family, making it ideal for very high-density printing where spot containment is critical.

Yes — ONCYTE® AVID is the only ONCYTE® variant for which standard western blot blocking buffers such as 1–5% non-fat milk in PBS or TBS are routinely recommended. This is because AVID supports colorimetric and chemiluminescent detection, where protein-based blocking buffers are standard practice. For fluorescence detection on AVID, switch to a fluorescence-optimized blocking buffer such as SuperG™ to minimize background autofluorescence from milk proteins.

For purified proteins and antibodies, a printing concentration of 0.1–1.0 mg/ml is recommended. The upper end of this range is appropriate for antibodies and glycoproteins. For complex lysates, titration across a concentration series (typically 0.1–2.0 mg/ml total protein) is recommended to identify the linear detection range for your targets.

ONCYTE porous nitrocellulose slides are well suited to near-infrared fluorescence detection because intrinsic nitrocellulose fluorescence is substantially lower at longer wavelengths. Grace Bio-Labs reports that detection above 650 nm can nearly eliminate the fluorescence background associated with porous nitrocellulose and bring background levels closer to those of glass.

Grace Bio-Labs demonstrated near-infrared detection using cell lysates printed on ONCYTE SuperNOVA, with Alexa Fluor 647, IRDye 680, and IRDye 800. The reported comparisons showed higher signal-to-noise in the near-infrared range than at visible wavelengths.

For a new protein microarray or RPPA workflow using near-infrared fluorescence, SuperNOVA is a strong substrate to consider, particularly when a wide quantitative dynamic range is required.

Grace Bio-Labs reports a protein-binding capacity of approximately 40 µg/cm² for porous nitrocellulose. This high binding capacity is one reason porous nitrocellulose is particularly useful for applications such as reverse-phase protein arrays, where samples can contain relatively low concentrations of target proteins.

The manufacturer reports that this capacity can allow researchers to increase the amount of protein deposited in an array spot by performing multiple depositions of dilute samples rather than relying exclusively on downstream signal amplification.

For low-abundance protein detection and tissue or cell lysate arrays, the high binding capacity of porous ONCYTE nitrocellulose can be an important advantage.

Yes. ONCYTE® AVID is compatible with all major contact and non-contact microarray printing platforms, including pin-based arrayers, piezoelectric dispensers, and inkjet printing systems. Printing should be performed at 50–55% relative humidity to prevent sample evaporation. No pre-treatment or activation of the slide surface is required prior to printing.

ONCYTE® AVID can support RPPA workflows, however ONCYTE® SuperNOVA is strongly preferred for RPPA applications due to its 7+ log dynamic range — significantly wider than AVID's 5–6 log range. For samples spanning a very wide concentration range, SuperNOVA will deliver more accurate quantification across the full dilution series. AVID is the better choice for RPPA experiments where colorimetric or chemiluminescent detection is required.

For purified proteins, a concentration of 0.05–1 mg/ml is optimal for most applications. The upper end of this range is recommended for antibodies. Concentration optimization may be required for specific proteins or complex mixtures such as cell lysates.

No. Printing may be performed at room temperature as long as humidity is maintained at approximately 50–55% to prevent sample evaporation during the spotting process.

Yes. ONCYTE porous nitrocellulose slides are well suited to tissue lysate arrays and reverse-phase protein arrays (RPPA). Grace Bio-Labs describes RPPA as an application in which tissue or cell lysates are arrayed for quantitative analysis of proteins and biomarkers.

The high protein-binding capacity of porous nitrocellulose is particularly useful for dilute lysate samples. Grace Bio-Labs reports that porous nitrocellulose can bind approximately 40 µg/cm² of protein and describes the material as well suited for detecting low-abundance targets in complex protein mixtures. Grace Bio-Labs has also reported RPPA experiments using ONCYTE AVID and SuperNOVA, including fluorescence and near-infrared detection approaches.

Yes. ONCYTE AVID is specifically identified by Grace Bio-Labs as suitable for chemiluminescent detection. The ONCYTE selection guide lists AVID as a preferred substrate for colorimetric and chemiluminescent detection, while also indicating compatibility with fluorescence applications.

If your assay uses chemiluminescence rather than fluorescence, AVID is therefore an appropriate ONCYTE substrate to consider.

Yes. Samples containing urea are routinely printed on ONCYTE® Film Slides without performance impact. ONCYTE® slides are chemically resistant to reagents commonly used in cell analysis assays, including up to 50% formamide. Note that acetone, ethanol, and methanol are not recommended — isopropanol and butanol are suitable substitutes. DMSO concentration should not exceed 5% as higher concentrations may negatively affect nitrocellulose integrity.

The optimal blocking buffer depends on your detection method. Colorimetric and chemiluminescent detection workflows are compatible with standard western blot blocking buffers such as PBS or TBS containing 1–5% non-fat milk. For fluorescent detection, protein-based blocking buffers can introduce background fluorescence — SuperG™ Protein Array Blocking Buffer has been specifically optimized for fluorescent microarray assays and delivers a high signal-to-noise ratio with minimal background.

ONCYTE® Film Slides are compatible with virtually all detection systems, including isotopic, chemiluminescent, chromogenic, and fluorescent detection. AVID offers the broadest detection compatibility across all four variants.

Non-printed slides should be stored at room temperature in their original packaging. Printed slides may be stored at 4°C for short-term storage or at -20°C for long-term storage. An overnight incubation at 4°C after printing is recommended to maximize protein binding before use.

IgG pre-labeled with a fluorophore should be spotted on every array to confirm proper protein binding. Buffer-only spots enable background subtraction, and secondary antibody-only stained slides serve as negative controls. Spotted replicates for each protein are strongly recommended to ensure statistical confidence in your results.

No. Re-use of ONCYTE® Film Slides is not advisable. Each slide is designed for single-use to ensure consistent, reproducible results.

Yes. ELEXAN Scientific ships internationally. We ship in-stock items on the same day.