Spago Nanomedical AB (publ) today announced the publication of data on the composition, stability, and mode of action for its leading candidate drug 177Lu-SN201. The preclinical results shows that the candidate drug accumulates favorably in tumors, inhibits tumor growth, provides prolonged survival compared to control, and is suitable for systemic treatment of cancer. The paper […]
https://clinlabint.com/wp-content/uploads/sites/2/2023/01/spago.png3731024panglobalhttps://clinlabint.com/wp-content/uploads/sites/2/2020/06/clinlab-logo.pngpanglobal2023-01-17 09:45:162023-01-17 10:02:58Spago Nanomedical publishes scientific paper on positive preclinical data with Tumorad® as treatment of solid tumors
Senior Electrical Design Engineer Dr Alex Beaseley looks at current applications of Artificial Intelligence as applied to real problems in scientific instruments. He demonstrates how a Neural Network approach can be deployed to analyse real-world images and determine key properties from the data with far more accuracy and far faster than traditional detection techniques.
In recent years – the scientific community has increasingly looked at Artificial Intelligence (AI) as a future tool that can deliver great benefits when applied to operations and measurements that instruments undertake. But what exactly is AI?
Firstly, let’s define a few terms you may have heard of: Machine Learning is the process to create Artificial Intelligence (AI). Machine learning can be applied through several different mechanisms which include “fuzzy logic”, “discriminant analysis” and “neural networks”. Due to their ability to process computationally intensive problems, neural networks are the basis of most commercially-viable AI that could be applied to the type of problems that scientific instruments try to solve.
The limit to implementing a neural network is simply the number of “nodes”, or possible connections, in the processor being used. The number of nodes in the human brain is orders of magnitudes greater than even the most powerful processors can muster. The much-vaunted “singularity” where a human consciousness could be uploaded in silico is still only the stuff of science fiction. However, in the real world, neural networks have an important role to play.
https://clinlabint.com/wp-content/uploads/sites/2/2021/12/ziath.png610542panglobalhttps://clinlabint.com/wp-content/uploads/sites/2/2020/06/clinlab-logo.pngpanglobal2021-12-13 13:02:272021-12-15 09:42:10What is AI and how can it be applied to scientific instruments?
Solid phase extraction (SPE) is a sample preparation method for the clean-up of samples before chromatographic analysis such as HPLC, and GC. SPE offers a number of advantages to the analyst, including less system downtime and troubleshooting, cleaner chromatograms with a reduction of contaminating compounds, and greater reproducible analyte recoveries. Traditionally, SPE methods use loose-filled resins which often create problems such as voids in the sorbent beds leading to channelling and inconsistent flow-through of solutions. This leads to reduced interactions between analytes and the active resin thus leading to inconsistent results and poor analyte recovery.
The Microlute® CP SPE range from Porvair Sciences, offers a unique, solid hybrid polymer structure which is made up of an interconnected network of evenly distributed pores combined with the retentive media (Figure 1). This design enhances the flow-through of samples to maximise interactions between analytes and the solid phase to deliver a highly reproducible SPE method.
This application note demonstrates the robust SPE LC-MS methodology of the Microlute® CP Reverse Phase (RP) SPE 30 mg plates on a range of neutral, acidic, and basic analytes. In addition, comparing recoveries and reproducibility will highlight the performance benefits over loose-filled methods of SPE.
With the increasing pressure of widespread testing across many nations around the world, many privately held diagnostic labs are turning their attention to the new possibilities offered by community COVID-19 screening and testing.
While the basic principle of using “gold standard” PCR test kits is now well established, there are still some issues surrounding the selection of consumables and the commensurate tracking of patient samples from point-of-sampling through the workflow to an end result. This short article looks at how 2D-bar coded tubes, tube readers and automatic tube selectors can significantly improve workflow automation and thereby reduce costs through quicker processing times whilst simultaneously reducing the risk of cross-sampling or losing samples all together.
One of the key challenges for smaller private testing labs is how to track large numbers of COVID-19 patient samples passing through using technicians who may be unfamiliar with these new protocols. To cope with the vast demand for COVID-19 sample testing, many laboratories have been asked to increase their daily throughput by as much as 10 times their normal workload.
Evolution of sample management
It was the advent of 2D-barcoded tubes that started the evolution of sample management from its basic and rudimentary beginning to the sophisticated tube and sample tracking applications that exist today. Sample management is now thought of as a critical analytical discipline by many organisations. The biggest issue for sample tracking during the current COVID-19 pandemic has been the availability of suitable consumables, followed by the availability of instruments for testing.
In the USA where the scale of the pandemic has been considerable – many individual states have had the demand to test 100,000 samples per day. Therefore, it is not hard to see why if a lab uses 96-well PCR plates for this testing they will need over a 1000 plates per day. Typically, these are sold in cases of 100 plates so that’s 10 cases per day, 50 cases per week. If all 52 states across the USA did that it would be 2600 cases of PCR plates per week. Now add in further demand from Europe, Australia, South East Asia and Africa the task of trying to mould, sterilise, pack and ship that many plates, even distributed across different manufacturers is a major logistical problem. Add to that the liquid handling tips and the RT-PCR and RNA extraction reagents which are also in short supply and the scale of the problem becomes apparent. Consequently, over the past 16 months, there have been regular shortages of the very 2D-barcoded tubes which were so desperately needed to help track large numbers of COVID-19 patient samples. Thankfully, as we move into the second half of 2021 – supply is beginning to catch up with the increased demand for these specialist consumables.
Explosion in sample test numbers
Most private testing laboratories have been challenged by the explosion in sample test numbers where they need to reliably track suspected COVID-19 infected patient swabs to 2D-coded tubes and then through to racks of 96 tubes. For this task a fast scanner that takes and stores high quality images is the preferred solution for establishing a traceable workflow of scanned patient swab tubes through to RT-PCR ready 2D-coded tube samples. As camera-based instruments, the Ziath Cube and Mirage scanners combine high image quality and fast scanning to provide reliable results in just a couple of seconds. The Mirage accepts all SBS-format tube racks, whilst the Cube can additionally accept the larger Cryobox format, making it easy to present coded sample tubes, even when wearing cryoprotective or anti-contamination clothing.
It is also possible to combine 2D bar coded tube readers with 96 position automatic tube selectors, such as the Ziath Mohawk. In this way – smaller testing labs can take advantage of a cost-effective “cherry picking” system for quickly and accurately selecting individual COVID-19 sample tubes from with 96 position tube racks. By linking directly with a camera scanner, the original position of the tube and any new position of the withdrawn tube can be accurately and quickly recorded.
Of course, all this vital sample location data needs to be entered into a LIMS or database of some sort so that the RT-PCR results can be tied directly to the correct patient samples. There are many systems and software available for this. One of the simplest and most cost-effective is the Samples software from Ziath. This basic “What is it?, where is it?” programme is an easy-to-use relational database that can be customised to track samples by any number of user-defined tracking tags, making it easy to find. For example, “all patients with positive RT-PCR result, over 50, who live in Cambridge, MA”.
Sample preparation is important in any type of chromatography analysis. While it can add on extra time, the process of cleaning up samples before injection onto a system results in a range of benefits to the analyst – better recoveries, more reproducible analysis, less downtime of instruments, reduction of troubleshooting, as well as less complex chromatograms due to the reduction of unwanted compounds being injected. All of these can result in time saved which could be needed for repeated work or maintenance on instruments.
Traditional SPE products consist of a loose-filled resin sandwiched between two frits. While this is known to work, it can come with some problems which can complicate analysis or result in poor data being produced. These problems are a result from how the product is packed into a well or cartridge – voiding can occur under the top frit, channels could form through the resin bed which can cause less efficient interactions between the resin and the analyte(s) or there could be variation on compression or resin weight that was dosed into each product.
Figure 1. Common issues associated with loose-filled SPE methods
The Microlute® CP SPE products consist of a unique hybrid design of a solid interconnected network of evenly distributed pores combined with retentive media. The advantage of this design is that flow through the product is consistent and increases the interaction between the analytes and retentive media present within the structure. These two features combined results in a product which offers both high recovery values as well as reproducible results. This technical note uses the 30 mg Microlute® CP Strong Cation Exchange (SCX) 96 well plate to compare performance in recoveries and reproducibility against five competitor loose-filled 30 mg SCX products.
Figure 2. Schematic of the hybrid polymeric structure showing the porous structure of the frit with the active resin immobilised throughout the pore structure
The Microlute® CP SCX product is a mixed-mode polymeric SPE product – a combination of ion exchange and reversed phase. This results in a product that has two retention mechanisms which can be fine-tuned to allow more flexibility in the SPE method. The reversed phase functionality allows for separation of analytes on hydrophobic interactions, allowing for retention to be altered by organic modifier concentration. Whereas ion exchange allows for selective strong ionic interactions between the resin and the charged analytes. The introduction of polymeric resins to SPE has resulted in some extra advantages over using silica-based resins . These include:
Polymeric structures do not contain any of the highly active sites found in These include silanol groups which can cause unwanted secondary interactions with analytes which in some cases could cause irreproducible recoveries.
Silica’s structure is also very susceptible outside of the pH range of 2 – 5. If pH is outside this range, hydrolysis of the silica or bonded functional group on the surface could occur.  This will result in very poor and irreproducible recoveries. On the other hand, polymeric resins are resistant to pH allowing them to work over the whole pH range (pH 0 – 14).
Functional groups bonded to a silica surface need to be conditioned with an organic solvent to activate the retention mechanism then equilibrated with an aqueous Whilst polymeric resins do not necessarily need to go through this conditioning step.
Polymeric resins are less sensitive to drying out during the SPE process where silica resin can become dry and lose their retentive function. 
Strong ion exchange does not work well for strongly acidic or basic analytes (analytes which have a charge over the whole pH range) due to the irreversible binding of charged analyte to the charged ion exchange resin. Weak analytes do work well with strong ion exchange. This is because it is possible to turn the analyte’s charge on or off for a weakly acidic or basic analyte allowing selective binding with a change of pH. To optimise this binding, the 2 pH rule is applied:
When the pH of the solution in which an analyte is dissolved is equal to the pKa value of the analyte, the analyte is 50% ionised, pH can then be used to adjust how ionised a compound is:
Figure 3. A diagram to show the 2 pH rule for a weak acid compound and weak basic compound , with a pKa of 4 and 8, respectively
For a typical strong ion exchange method, analytes are pre-treated to a pH where they are charged and then loaded onto the resin. This allows them to bind strongly to the resin with the ionic interactions. The same pH will be maintained on the wash steps of the method allowing the analyte(s) to keep binding to the resin while washing off interfering com- pounds. To allow elution, pH is changed to neutralise the charge allowing the analyte(s) to stop binding to the resin and elute from the product.
A stock of 1,000 µg/ml of all the basic analytes was made in methanol. A basic load solution was made by diluting 500 µL of the stock solution to 50 mL with water containing 0.1% (v/v) formic acid.
Solid Phase Extraction Method
For both the Microlute® CP SCX product and competitor products, a total of 12 wells were tested. Each well tested was conditioned with 1,000 µL methanol, then equilibrated with 1,000 µL of water. 1,000 µL of basic load solution was then loaded onto the plate in full. Once loaded, 1,000 µL of water containing 0.1% (v/v) formic acid solution in water was used to wash the sorbent. Followed by a strong organic wash of 0.1% (v/v) formic acid solution in methanol.
To elute the analytes of interest, 500 µL of methanol containing 5% (v/v) ammonia was used. The eluent was then evaporated to dryness at 35°C under N2 using a Porvair Sciences Ultravap® Levante (# 500226). A repeat elution was performed using another 500 µL of methanol containing 5% (v/v) ammonia and evaporated to dryness with the same method.
To reconstitute each sample, to each collection vial, 10 µL of 1,000 µg/ml caffeine (ISTD) was added, followed by 790 µL of 60% (v/v) methanol/water containing 0.1% (v/v) formic acid to create a 12.5 µg/mL solution. A further dilution was made using 40 µL of 12.5 µg/mL solution with 760 uL of 60% (v/v) methanol/water containing 0.1% (v/v) formic acid, creating 0.625 µg/mL solutions ready for injection.
Results and Discussion
Figure 4. Chromatogram of basic analytes calibration standard.
Peak assignments can be found in Table 3.
Table 3. Properties and MS parameters for the basic compounds analysed – aPredicted value from Pubchem 
Recovery Comparisons against Competitors
Figure 5. Analyte recovery comparisons against equivalent competitor SPE products.
Reproducibility Comparison against Competitors
Figure 6. Analyte %RSD comparisons against equivalent competitor SPE products.
For reproducibility, a lower %RSD means the recovery was more reproducible. The analyte’s %RSD values can be seen in Figure 6. The Microlute® CP SCX managed to maintain a %RSD value of less than 2.6% for every compound analysed. It outperformed every competitor for reproducibility on each compound with only amitriptyline being closely matched. There was no issue of irreproducible results for either the most extreme hydrophilic compound or the most hydrophobic. This again shows that the Microlute® CP SCX product is performing excellently across a wide range of basic analytes.
The Microlute® CP SCX 30 mg 96 well plate can effectively retain a wide range of hydrophilic and hydrophobic basic compounds. It offers advantageous recoveries across the range of different classes of analytes. Lower %RSD values are seen when comparing against competitor plates for every compound analysed in this study – 1.6%RSD on average for the Microlute® CP SCX compared to the 2.4%RSD (best competitor) and 5.9%RSD (worst competitor). This ensures the product gives reliable and reproducible results which is an important metric in testing where confidence in the data output is required.
F. Poole, Solid-Phase Extraction, Elsevier, 2020, p. Chapter 3: Porous polymer sorbents.
V. Brady and J. V. Walther, “Controls on silicate dissolution rates in neutral and basic pH solutions at 25°C,” Geochimica et Cosmochimica Acta, vol. 53, no. 11, pp. 2823-2830, 1989.
N. Qureshi, G. Stecher, C. Huck and G. K. Bonn, “Preparation of polymer based sorbents for solid phase extraction of polyphenolic compounds,” Central European Journal of Chemistry, vol. 9, no. 2, pp. 206-212, 2011.
Copyright 2021. Porvair Sciences Ltd. All rights reserved.
Whilst every effort has been made to ensure the accuracy
of this document, due to continuous product development,
the data contained is subject to constant revision
and Porvair Sciences Ltd. reserves the right to change,
alter or modify its contents. Porvair Sciences and
JG Finneran Associates, Inc., and Kbiosystems
are divisions of Porvair plc.
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Waltham, MA–Nova Biomedical to host “COVID-19 Bedside Glucose Management: Risk of Ascorbic Acid and Hematocrit Interference,” a webinar led by Charbel Abou-Diwan, PhD, Director of Medical and Scientific Affairs, to help inform and support healthcare workers treating COVID-19 patients.
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