Author Archives: tiffany liew

Vaccine Induce False Positives in Preventative HIV Trials

Posted on March 26, 2018 | Leave a comment

Everyday there are over 7500 cases of human immunodeficiency virus, HIV, that are reported all over the world and the need for an effective Food and Drug Administration-approved vaccine is constantly growing. Researchers have proposed various approaches that have reached clinical trials of 30,000 participants, however, preventative HIV-1 vaccines have the risk of giving false test results. This is due to the ability for trial participants to generate HIV antibody responses that are induced by the vaccination. During routine HIV testing that use antibody detection methods, false positives may be found and can cause an incorrect diagnosis.

Fig. 1: Vaccination via Needle                       Source: Flickr by VCU CNS

This study assesses the appearance of vaccine induced sensitive/reactivity, VISP, in HIV vaccine trials, which were delivered in different systems and with HIV inserts. In 2010, Dr. Baden and her team used three FDA approved enzyme immunoassay (EIA) HIV antibody kits, which detect VISP by identifying the antibodies that were induced and a diagnostic HIV algorithm that examines the frequency of VISP in healthy adults.

Out of the 2176 participants that were free of the HIV infection and given a vaccine, 41.7% of them had VISP. However, the frequency of VISP varied between vaccine types; 86.7% adenovirus 5 product, 53.4% of poxvirus and 6.3% of DNA -alone product recipients that were given those vaccines had VISP.

Fig. 2: 2176 Non-HIV vaccine recipients with true negative or false positive results

The HIV testing kits also varied in VISP results between 40.9% and 8.8% of participants. Their findings suggested that VISP depended on the vaccine that was administrated as well as the EIA used.

Fig. 3: Microscopic HIV Budding                                    Source: Wikipedia

If VISP induces false positive results, it could affect these participants’ opportunity to donate blood or organs, obtain medical or life insurance, hired for employment and even being able to immigrate into certain countries. Testing for VISP is crucial after every study to ensure no societal harm or incorrect reports enter the health system. However, some clinicians may glance over full patient history due to added time and cost.

The development for a vaccine gets closer to becoming approved but there are still many obstacles that researchers must face. With the race against the clock, people who are diagnosed with HIV slowly acquire AIDS if not treated. If researchers can find a preventative vaccine, HIV/AIDS could be avoidable in the future.

-Tiffany Liew

 

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Fingerprints Tell All: The Fastest Drug Detection Method

Posted on March 5, 2018 | 1 comment

Cocaine is the second most illicit trafficked drug around the world, with a global production of 866 metric tonnes in 2016, and is currently on the rise in many regions of Europe. For current techniques to determine this illegal substance in a person’s system, specialists must conduct blood or urine testing procedures that require laboratory resources and long wait periods. However, in 2017 researchers at the University of Surrey proposed a method of taking fingerprint tests that can trace cocaine in the system within a matter of minutes.

Fig. 1: Cocaine in Powder Form Drawn into lines Source: Pixabay

Dr. Catia Costa, Dr. Melanie Bailey and their team took fingerprints from patients seeking rehabilitation. Fingerprints were analyzed using chromatography paper, a paper spray mass spectrometry technique, looking at concentrations of cocaine, benzoylegonine (BZE) and methylegonine (EME). Both substances are excreted from the fingertips when the body metabolizes the drug.

Cocaine is a highly addictive substance, derived from the South American coca plant, that inhibits the reuptake of serotonin, norepinephrine and dopamine. This results in higher concentrations of these neurotransmitters in the brain providing the user with increase levels of euphoria, energy and elevated mood. The drug is so potent that the metabolites can stay in the system for 2-4 days.

Fig. 2: Chemical Structure of Cocaine             Source: Wikimedia Commons

The paper is first prepared by applying a internal standard, spray solvent and then a voltage. After the fingerprint have been pressed, silver nitrate fingerprint development solution is added and exposed to ultraviolet light that will enhance black ridge fingerprint marks on the paper. Oral fluid results of cocaine had a detection limit of 1ng/mL. They found that 98.7% of the results gave a true positive while 2.5% gave a false positive with a single fingerprint.

Fig. 4: 12 Participants in the rehabilitation centre and the Amount of Cocaine found in their Oral Fluid Results

The oral fluid results were then compared with fingerprint analysis and the researchers found every finger except one gave positive results for one substance.

Fig. 5: 12 Participants (same from Fig. 4) and at least one substance (Cocaine, BZE, EME) detected on fingerprints

Law enforcement, prisons, courts, and drug rehabilitation centres can utilize this technique for a faster and more effective process of collecting drug. It takes 4 minutes per sample but research continues to look for faster techniques that can possibly take only a matter of seconds to develop in the near future.

– Tiffany Liew

References

Becue, A.; Moret, S.; Champod, C.; Margot, P. Use of stains to detect fingermarks. Biotech Histochem. 2011, 86, 140-160.

Costa, C.; Webb, R.; Palitsin, V.; Ismail, M.; dePuit M.; Atkinson, S.; Bailey M.J. Rapid, Secure Drug Testing Using Fingerprint Development and Paper Spray Mass Spectrometry. Clin. Chem. 2017, 11, 1745-1752.

Kuwayama, K.; Miyaguchi, H.; Yamamuro, T.; Tsujikawa, K.; Kanamori, T.; Iwata, Y.T.; Inoue, Hiroyuki. Effectiveness of saliva and fingerprints as alternative specimens to urine and blood in forensic drug testing. Drug Test. Analysis. 2016, 8, 644-651.

Mejia, D.; Posada, C.E. Cocaine Production and Trafficking: What Do We Know? World Bank Group. [Online] 2008, 4618 https://openknowledge.worldbank.org/handle/10986/6719 (accessed Mar 5, 2018).

Shen, L.; Zhang, J.; Yang, Q.; Manicke, N.E.; Ouyang, Z. High throughput paper spray mass spectrometry analysis. Clin. Chim. Acta. 2013, 420, 28-33.

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Posted in Chemistry in the news, Issues in Chemistry

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Can Cigarette Butts Be the Next Huge Source of Fuel?

Over a billion people all over the world smoke on average six trillion cigarettes every year and their littered cigarette butts pose a large environmental waste and water pollutant problem to the community and wildlife. However, a study done by researchers at the University of Nottingham uncovered that these waste products can be used as a source of hydrogen storage material.

Figure 1: Cigarette Butts                                          Source: Flickr by Alexander C. Kafka

As of November 2017, Materials Chemistry Professor Dr. Mokaya and his undergraduate student Troy Blankenship successfully converted cigarette butts into the starting materials needed for hydrogen storing. Hydrogen can be used as an energy source because of its capacity to generate heat when burned or electricity when reacted with oxygen. This new discovery pushes industries closer in the direction to switch from coal based material to biomass or waste based reusable material for power and fuel.

Cigarette butts contain cigarette filters, a non-biodegradable film base material, called cellulose acetate. These compounds have been a popular subject of waste valorization, a form of converting existing biomass into high performance produce. Cigarette butts produce porous carbons, which have the highest hydrogen storage capability to be currently documented. These findings have a major impact on reducing the litter on public properties and the environmental pollutant of cigarette butts. Toxic heavy metals are found in cigarettes and can wash up into large bodies of water, possibly harming humans and wildlife.

Figure 2: Cellulose Acetate                       Source: Google by Wikimedia Commons

The littered cigarette butts undergo a process of hydrothermal carbonization by adding only water and heat to synthesize a carbon compound called hydrochar. Hydrothermal carbonization imitates the natural process of coal formation in a close container subject to high temperature and intense pressure. Once this product is activated, the compound becomes highly oxygenated, rich in pore volume and increased in surface area. To measure the hydrogen concentration, the compound was weighed before and after the addition of purified hydrogen. Hydrochar can then store hydrogen that can replace gasoline to fuel vehicles and other forms of transportation or natural gas to heat buildings and houses.

Linked Vimeo Video: Biomass Animation by David Curtis

Further research needs to be done in the production of sustainable energy storage materials in the investigation of valorization possibly solving the waste of 800,000 metric tons of cigarette butts produced every year. With oil increasing in value, decreasing in amount and massive increase in carbon dioxide emissions, the need to stray away from fossil fuels is bigger than ever.

-Tiffany Liew

References:

Marksman, D.E., Pirverdyan, A.I., Mokhnachev, I.G., & Perepechkin, L.P. Cellulose acetate fibre for cigarette filters. Fibre Chem. 1971, 3, 292-293.

Mokara, R., & Blankenship, T. Cigarette butt-derived carbons have ultra-high surface area and unprecedented hydrogen storage capacity. Energy Environ. Sci.  2017, 10, 2552-2562.

Tuck, C.O, Perez, E. Horvath, I.T., Sheldon, R.A., & Poliakoff, M. Valorization of Biomass: Deriving More Value from Waste. Science. 2012, 337, 695-699.

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Posted on January 22, 2018 in Chemistry in the news

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