Sustainability and label free imaging


Sustainability started as one of the central tenets of deltaDOTs’ technology. Initially slanted towards a health and safety angle rather than a purely green standpoint, these criteria have become fused into one direct sustainable platform that avoids the logistics of label/dye supply and much of the single use plastic packaging issues in a modern laboratory.

This technology allows the user to perform dozens of analytical experiments on the same reusable capillary system. There is no carryover between experiments, no contamination risk and minimal carbon footprint.

This is in a High Performance Capillary Electrophoresis (HPCE) system with better than average data quality at a fraction of the operating costs of other systems.


Labels, stains, dyes and radioisotopes.

The use of labels, stains, dyes[1] and radioisotopes has been the common currency of molecular biochemistry for years and, the use of these molecules raise issues of sustainability. Every component of an experiment creates a carbon footprint of some kind. The production of labels, stains, dyes and radioisotopes each carry a penalty as will be expanded upon later, but the removal of a major experimental component can only have positive outcomes for sustainability. Here is also the problem of quality. The first reaction to the failure of the experimental process is not usually to blame the manufacturer or component. This wastes time and resources and increases the overall carbon footprint

o the experiment. As an example, the author studied 4 recombinant proteins from overseas and found 3 to be very poor in quantity and quality including antigenicity. While not strictly a label, these proteins were being use as a biosensor toward Covid-19 antibodies, so good antigenicity was required to ensure that a binding event occurred.

The extra resources needed to deal with mutagens, teratogens and reproductive toxins may seem trivial individually, but taken as a whole soon add up significantly.

Added to the production, shipping and the green costs of packaging are the issues of disposal. Most modern fluorescent labels offer little problematic difficulties in disposal. The rising use of radioisotopes[2] does of course raise the normal disposal issues.


Single use plastics

The biggest issues of laboratories work are the use of disposable plastics. While the use of pipette tips are largely unavoidable other problems remain.

Since much of the infrastructure for re-usable glassware has been degraded due to cost-savings, but single-use plastics like Pasteur pipettes endure.

Added to this, and maybe less obviously, are the single-use plastics found in packaging.


The costs of production

Many systems use columns and pre-prepared capillary cassettes, seals and closures that are available from the manufacturer. These inevitably involve packaging, both as protective foam or polystyrene forms and the outside wrapping. All are accompanied by paperwork  which is now becoming web-based to some extent. These materials must be manufactured, usually not locally by any means, and all entails shipping and further packaging. As most suppliers are outsourcing to China and other countries there is the added supply chain compliance problems. Most companies cannot  guarantee that their supply chain is completely ethical, with the added pressures of pollution and work force treatment.

These deliverables are in response to the reliance developed over the past decade on convenience and also to a growing compliance structure. Rather than increase the strictures on good basic laboratory practice the trend has been to increase the cost of employing experienced scientists with a history of expertise into the less skilled and more economically viable model. Biopharmaceutical companies may struggle to reconcile these issues as sustainability becomes increasing important as a moral and investment decision parameter.


The cost of Disposal

Plastic waste falls into various categories. General waste (including plastic packing) goes into general black-bag rubbish which goes to landfill or incinerator with all the associated environmental issues that they entail.

Hazardous waste -orange/yellow bag –  all goes to incineration. This poses many issues such as emissions and final disposal

Much of it ends up in landfill or far worse, in recycle tips in the third world, where it is known medical single use items are recovered for re-use.



The environmental cost of these materials is of course not just in their  physical presence but in their transportation. It is easy to consider that the materials are made in the UK or Europe and shipped on-site. Even if the transporter uses an electric vehicle, they are not cost free. Energy is not created, only converted and this means there is a large element of oil, gas or nuclear behind each DHL truck trundling around. Further to this it has been the case for many years that most suppliers by far are manufacturing offshore with all the problems that entails. The quality of materials aside, the transfer of materials by unregulated container ships is well known to be a major source of carbon emissions and for short life span materials, the cost of air transport might be considered even worse.


deltaDOTs’ Label-Free sustainability solutions.

Label Free Intrinsic Imaging (LFIIÒ)

LFIIÒ measures the passage of the analyte across a 512-pixel photodiode array (PDA) at the appropriate wavelength without any labels, stains, dyes or radioisotope attached. For example, proteins are imaged by the absorption of UV light by their constituent peptide (amide) bond between each amino acid. The optics in the system are easily set to each specific wavelength between 200 and 300nm allowing a very broad spectrum of analytes to be accurately measured with high (<200Da) resolution and high repeatability.


This means there is no needs for the purchase of any labels, stains, dyes or radioisotopes with all the logistical and packaging problems that entails. This reduces the carbon footprint of each and every single analysis without sacrificing data quality.


Capillary block vs. disposable cassette

Fig 1. Loading the reusable capillary block. 

The deltaDOT system employs a multi-use aluminium capillary block that has excellent thermal properties. The block has a series of channels into which the user inserts a fused silica capillary. Although not as easy and convenient as a packaged plastic capillary cassette, this system represents a sustainable analysis system. The capillary is 375microns in diameter with an internal bore of on average 50microns, it is covered in a strengthening plastic cover that is easily removed with a capillary stripping machine. The capillary come on a 30 metre roll on a polystyrene spindle. This is the only large (14cm) non-recyclable part of the machine operation. As each capillary (usual length 32cm) lasts for 20-30 experiments the actual disposable detritus of the system is small. The glass vials should be recycled if the sample is non-hazardous.


This label-free approach coupled with the reusable cassette does not come with data quality penalties. In fact, the data quality exceeds most or all competing CE systems and overlaps Mass Spectrometers in some applications. This is due to a combination of advanced data acquisition and processing, the advantages of label-free detection and excellent thermal control.


deltaDOTs’ label-free technology can be a key stage I meeting sustainability targets

[1] Global protein labelling market size was valued at USD 2.09 billion in 2021

[2] Radio isotope labels–globally-at-3-57-cagr-verified-market-research-301681616.html