Which western blot imager fits your lab
Every one of our four imagers handles chemiluminescent blots, so choose by what else your lab needs to image. Only the Dual-Camera has a color camera for the ladder.
Chemiluminescent blots only
Chemiluminescence Imaging System
$12,960
Blots, plus the ladder in true color
Dual-Camera Chemiluminescence Imaging System
$17,990
DNA and protein gels as well
Multifunctional Imaging System
$18,990
Fluorescent blots, tissue sections or culture plates
Multifunctional Fluorescence Imaging System
$19,990
Chemiluminescence or fluorescence
Fluorescence is the better choice for quantifying bands or detecting two proteins on one blot, and chemiluminescence for finding faint bands.1,2 Of our four imagers, only the Multifunctional Fluorescence Imaging System images fluorescent blots as well as chemiluminescent ones.
Both methods start the same way, with a primary antibody bound to your protein and a secondary antibody bound to the primary. In chemiluminescence, the secondary carries an enzyme that turns a substrate into light. In fluorescence, it carries a fluorescent dye, which a light in the imager excites.
To measure a band, load an amount of protein inside the linear range, the span of loads where halving the protein halves the band’s signal.3 Past that range, the band no longer tracks the amount of protein.
Chemiluminescence
- In a study of quantitative blotting, Janes found that chemiluminescence gave stronger bands than fluorescence under the same conditions.2
- Chemiluminescence had a very limited linear range, and at high protein loads its signal often fell as more protein was loaded.2
- Chemiluminescent signal is generally linear only below 5 µg of protein per lane.1
Imaged by all four of our imagers.
Fluorescence
- With a fluorescent secondary antibody, the signal rises in step with the amount of protein over a wider range of loads than with chemiluminescence.1
- With no enzyme reaction, nothing amplifies a band’s signal out of proportion to its protein, but strong bands can still saturate.2
- With two dyes, one blot can show a protein’s phosphorylated form and its total amount, without stripping and reprobing.2
Imaged by the Multifunctional Fluorescence Imaging System, with excitation lights at 470, 530 and 650 nm.
What to compare in a western blot imager
A western blot imager has to record faint bands and strong ones on the same blot. So the faintest band its camera can detect and the range of signal it can measure matter more than its megapixel count. Compare imagers on camera sensitivity, dynamic range, imaging area, light sources and capture software.
Camera sensitivity
Faint chemiluminescent bands can need long exposures. Over a long exposure, the sensor also picks up dark current, a signal that builds up even in complete darkness, so western blot imagers cool the sensor to keep that background low. Cooled to 40 °C below ambient, the sensor in each of our imagers collects 0.0003 electrons of dark current per pixel per second, about one electron per pixel over an hour. That is less than the camera’s read noise, the 1.24 to 3.22 electrons of noise each pixel picks up every time the camera reads out an image.
A larger pixel gathers more light but resolves less detail. Binning makes the same trade on a camera with small pixels, by combining neighboring pixels into one. The Dual-Camera and both Multifunctional imagers can bin up to 3×3.
Bit depth sets how many shades of gray each pixel can record. A 16-bit image stores 65,536 levels, against 256 in an 8-bit image, so small differences between bands are kept.
What all four main cameras share
- Resolution
- 9 MP
- Pixel size
- 3.76 µm
- Image depth
- 16-bit
- Cooling
- 40 °C below ambient
- Read noise, by gain mode
- 1.24 to 3.22 e⁻
- Exposure
- 0.1 ms to 1 h
The Dual-Camera Chemiluminescence Imaging System also has a second, 45 MP color camera that photographs the pre-stained ladder in true color.
Dynamic range, protein load and saturation
Dynamic range is the span from the faintest band an imager can detect to the strongest it can measure before the signal saturates. Film’s dynamic range is so small that measuring bands on film is almost impossible, so Janes avoided it entirely for quantitative blots.2 All four of our imagers use a cooled digital camera instead.
The main camera in each of our imagers spans a little over four orders of magnitude in one exposure. That is its full well, the most signal a pixel can hold, divided by its read noise: 50.5 ke⁻ against 3.22 e⁻ in low gain, about 15,700 to 1.
Saturation can also happen on the blot itself, not only in the camera. Janes names three causes: antibodies crowding the protein’s binding sites, quenching of fluorescent antibodies and oxidation of enzyme-linked ones.2
Most labs load 10 to 100 µg of total lysate per lane, often with no scientific basis for choosing that amount.3
Janes diluted HT-29 cell extract in twofold steps from 200 µg to 0.1 µg, a load below the limit of detection.2 The slider steps through the same loads, stopping at 0.2 µg.
Move the slider to a load. Each row is one published finding, and its bar shows whether the load you picked is inside the linear range the finding reports, past it or saturated.
Within the 10 to 100 µg most labs load.3
25 µg per lane, within the 10 to 100 µg most labs load. Chemiluminescence, typically: past the linear range. Housekeeping proteins, typically: saturated. Actin and p38 by fluorescence: inside the linear range. Hsp90 and tubulin by fluorescence: saturated.
Chemiluminescence, typically
Linear below 5 µg1
Past the linear range
Housekeeping proteins, typically
Saturated above about 4 µg3
Saturated
Actin and p38 by fluorescence
Linear up to 50 µg2
Inside the linear range
Hsp90 and tubulin by fluorescence
Saturation starts below 25 µg2
Saturated
Inside the linear range
Doubling the load doubles the band’s signal.
Past the linear range
The band’s signal no longer changes in step with the load.
May be saturated
Saturation starts somewhere in this stretch.
Saturated
The band has stopped growing with the load.
Below where saturation starts
Show as a table
The rows come from different papers, proteins and methods, and they do not all agree. Actin stayed linear up to 50 µg by fluorescence in Janes’s tests.2 Taylor and Posch report that housekeeping proteins, actin among them, typically saturate above about 4 µg.3
Even under the same conditions, the linear range differed from protein to protein in Janes’s tests.2 Taylor and Posch advise running a twofold dilution series of your own sample for each antibody, then loading near the middle of its linear range.3
Comparing each band’s change with the change in its protein, Janes found that chemiluminescence overstated the change for Hsp90 and GAPDH, and a saturated blot understated it for ERK2.2
- Change in protein
- Change in band intensity
- More than the value shown
Fold change, on a log scale
“When chemiluminescence is used cavalierly,” Janes warns, “there is a danger of wildly exaggerated claims.”2
Imaging area
The imaging area is the largest field the camera captures in one image. It has to hold your largest membrane, or every membrane you want to image together.
For blots, the Dual-Camera images a square 136 mm on a side, and its field of view expands to 200 mm. Expanding spreads the same 9 MP over a larger field, so each pixel covers more of the blot. Both Multifunctional imagers image blots in 155 mm squares, except fluorescent blots, which get 136 mm on the Multifunctional Fluorescence Imaging System. DNA gels get 215 mm on both.
Before you order the Chemiluminescence Imaging System for large blots, ask us for its imaging area.
Enter the size of your membrane or gel to see how many fit in each imaging area, laid edge to edge. The areas are drawn to one scale.
Enter a width and a height to start.
Chemiluminescence Imaging System
Imaging area not listed
Ask us before you order
Dual-Camera
Blots
136 × 136 mm
Dual-Camera
Blots, expanded field of view
200 × 200 mm
Multifunctional
Blots and protein gels
155 × 155 mm
Multifunctional
DNA gels
215 × 215 mm
Multifunctional Fluorescence
Chemiluminescent blots and protein gels
155 × 155 mm
Multifunctional Fluorescence
Fluorescent blots
136 × 136 mm
Multifunctional Fluorescence
DNA gels
215 × 215 mm
Light sources
Chemiluminescent blots give off their own light, so they need no light source. Gels and fluorescent blots need light from the imager. White light shows stained protein gels and the pre-stained ladder, UV light shows DNA gels, and excitation lights make fluorescent dyes glow.
Ask us how the Chemiluminescence Imaging System photographs the ladder.
Chemiluminescence Imaging System
No light source listed
Dual-Camera
Multifunctional
Multifunctional Fluorescence
Wavelength
White light
Protein gels stained with Coomassie or silver, and the pre-stained ladder.
In the Dual-Camera, Multifunctional and Multifunctional Fluorescence imagers.
UV light
DNA gels stained with ethidium bromide or a similar dye. The 310 nm transilluminator lights the gel from below, and the 254 and 365 nm epi-UV lights shine down on it from both sides.
In the Multifunctional and Multifunctional Fluorescence imagers.
Excitation lights
Each light excites one dye on a fluorescent blot, so each dye gives its own image. The imager with these lights also takes fluorescence images of whole tissue sections, culture plates and agar plates, though not of individual cells.
In the Multifunctional Fluorescence imager.
Show as a table
| Imager | White light | UV light | Excitation lights |
|---|---|---|---|
| Chemiluminescence Imaging System | No light source listed | ||
| Dual-Camera | Yes | No | No |
| Multifunctional | Yes | 254, 310 and 365 nm | No |
| Multifunctional Fluorescence | Yes | 254, 310 and 365 nm | 470, 530 and 650 nm |
Capture software
All four imagers show a live view and set the exposure automatically. Each can record an exposure as a time-lapse, so you can pick the best frame afterward. Each also offers cumulative exposure, which extends an exposure after the first run.
On the Dual-Camera and both Multifunctional imagers, the live view warns you when pixels are brighter than the camera can record. A band can saturate on the blot before any pixel does, so you still need a dilution series of your own sample to find the band’s linear range.3,2
The Dual-Camera and both Multifunctional imagers can clear non-specific antibody signal from the pre-stained ladder’s bands. The Dual-Camera also restores the ladder’s true colors, and the Multifunctional Imaging System also corrects overexposed ladder bands. The Multifunctional Fluorescence Imaging System can invert the ladder’s image, so you can use a standard pre-stained ladder on fluorescent blots instead of a fluorescent one.
Ask us which analysis software comes with each imager and which file formats it saves.
Our four western blot imagers compared
The table gives every specification from the four product pages. Where it says Not listed, ask us.
Find the imagers that fit your lab
Pick what your lab images besides chemiluminescent blots. Each card then shows whether that imager covers each of your choices.
Pick one or more to see which imagers fit.
Chemiluminescence Imaging System
Chemiluminescent blots
Dual-Camera Chemiluminescence Imaging System
Chemiluminescent blots, with the ladder in color
Multifunctional Imaging System
Chemiluminescent blots, DNA gels and protein gels
Multifunctional Fluorescence Imaging System
Fluorescent and chemiluminescent blots, gels, tissue sections and culture plates
Full specifications
Showing all 37 rows.
| Specification | Chemiluminescence Imaging System $12,960 | Dual-Camera Chemiluminescence Imaging System $17,990 | Multifunctional Imaging System $18,990 | Multifunctional Fluorescence Imaging System $19,990 |
|---|---|---|---|---|
| What it images | ||||
| Chemiluminescent blots | Yes | |||
| Fluorescent blots | No | Yes, three excitation lights | ||
| DNA gels | Not listed | No | Yes | |
| Cutting bands from DNA gels | Not listed | No | Yes, behind a UV shield | |
| Protein gels | No light source listed | Not listed, has white light | Yes | |
| Tissue and culture plate fluorescence | No | Yes | ||
| Monochrome camera | ||||
| Resolution | 9 MP, 3000 × 3000 | 9 MP, 2992 × 3000 | 9 MP, 3000 × 3000 | |
| Pixel size | 3.76 µm | |||
| Cooling | 40 °C below ambient | |||
| Dark current | 0.0003 e⁻ per pixel per second | |||
| Image depth | 16-bit | |||
| Exposure | 0.1 ms to 1 h | |||
| Read noise, by gain mode | 1.24 to 3.22 e⁻ | |||
| Signal to noise, by gain mode | 42.2 to 47 dB | |||
| Full well | 50.5 ke⁻ low gain | 16.5 ke⁻ high gain, 50.5 ke⁻ low gain | ||
| Binning | Not listed | 1×1, 2×2, 3×3 | ||
| Lens | Not listed | Prime, 17 mm, F0.95 to F16 | Motorized zoom, 17 mm, F0.95 to F16 | Motorized, 17 mm, F0.95 to F16 |
| Second camera | ||||
| Color camera | None | 45 MP color, 2.315 µm pixels, 8-bit, 17 µs to 15 s | None | |
| Light sources | ||||
| White light | Not listed | Yes | ||
| UV transilluminator | Not listed | No | 310 nm | |
| Epi-UV | Not listed | No | 254 and 365 nm | |
| Excitation lights | No | 470, 530 and 650 nm | ||
| Optional blue and white light | No | Switchable, 3 power levels each | ||
| UV shield for cutting | Not listed | No | Yes, OD over 7 | |
| Imaging area | ||||
| Blots | Not listed | 136 × 136 mm, expands to 200 × 200 mm | 155 × 155 mm | 155 × 155 mm chemiluminescent, 136 × 136 mm fluorescent |
| Protein gels | Not listed | 155 × 155 mm | ||
| DNA gels | Not listed | No | 215 × 215 mm | |
| Software | ||||
| Live view | Yes | Yes, warns of overexposure | ||
| Automatic exposure | Yes | |||
| Time-lapse imaging | Yes | Yes, any frame in 0.1 s steps | Yes | |
| Cumulative exposure | Yes | |||
| Ladder tools | Not listed | Restores true ladder colors, removes non-specific antibody signal | Corrects overexposed or cross-reactive ladder bands | Removes non-specific ladder bands, inverts the ladder image |
| Computer, size and power | ||||
| Built-in computer | Not listed | 10.4-inch screen, Windows 10, 16 GB RAM, 512 GB SSD | ||
| Size (W × D × H) | Not listed | 400 × 371 × 700 mm | ||
| Weight | Not listed | 23.45 kg | 30.65 kg | 35 kg |
| Power | Not listed | Up to 200 W | Up to 300 W | |
| Mains voltage | Not listed | 90 to 132 or 180 to 264 V AC, 47 to 63 Hz | ||
Prices and stock are live from our store. Specifications are as listed on .
Common questions
- What is a western blot imager?
- A western blot imager is a dark cabinet with a cooled camera that records the light from the bands on a western blot, so you can see and measure them. Imagers with their own light sources can also image gels and fluorescent blots.
- How much does a western blot imager cost?
- Our four western blot imagers cost $12,960 to $19,990. The Chemiluminescence Imaging System costs the least, and the Multifunctional Fluorescence Imaging System costs the most.
- Can a chemiluminescence imager be used for fluorescent western blots?
- Only if it has excitation lights for your dyes. Of our four, the Multifunctional Fluorescence Imaging System has them, at 470, 530 and 650 nm.
- How much protein should I load per lane?
- Load near the middle of your antibody’s linear range, which you find by running a twofold dilution series of your own sample.3 That load can be well below the 10 to 100 µg most labs use.3 Housekeeping proteins used as loading controls typically saturate above about 4 µg per lane.3
- What imaging area do I need?
- One that holds your largest membrane, or all the membranes you image together. For blots, the Dual-Camera covers 136 mm squares, or 200 mm with its field of view expanded, and both Multifunctional imagers cover up to 155 mm. Ask us for the Chemiluminescence Imaging System’s imaging area.
- Do I need UV light on a western blot imager?
- Not for chemiluminescent blots, which give off their own light. On our imagers, UV light is for DNA gels stained with ethidium bromide or a similar dye, and for cutting bands from them. Both Multifunctional imagers have UV at 254, 310 and 365 nm, with a shield for cutting.
References
Eaton SL, Llavero Hurtado M, Oldknow KJ, et al. A guide to modern quantitative fluorescent western blotting with troubleshooting strategies. Journal of Visualized Experiments, 2014.
Janes KA. An analysis of critical factors for quantitative immunoblotting. Science Signaling, 2015.
Taylor SC, Posch A. The design of a quantitative western blot experiment. BioMed Research International, 2014.
