The technology, patented by CSIC, is also being applied in the early detection of some types of cancer
In addition, the total test time is 4 hours, 45 minutes, meaning clinical results could be obtained on the same day. The research is published today in the journal PLOS ONE.
The biosensor combines micromechanical silicon structures with gold nanoparticles, both functionalised with p24-specific antibodies. At the end of the immunoassay procedure, p24 is sandwiched between the gold nanoparticles and the micromechanical silicon structures. The gold nanoparticles have optical resonances known as plasmons. These are capable of scattering light very efficiently and have become one of the structures to attract most interest in the field of optics over the last decade. Micromechanical structures are excellent mechanical sensors capable of detecting interactions as small as intermolecular forces. The combination of these two structures produces both mechanical and optical signals which amplify one another, producing remarkable sensitivity, to detect the p24.
The technology, which has been patented by CSIC, is also being applied in the early detection of certain types of cancer.
“The chip itself, the physical part, is identical for HIV tests and for cancer biomarker tests. What changes is the chemical part- the solution we apply- so that it reacts accordingly to what we are looking for. That’s why our fundamental work is focused on developing applications for this new technology”, points out CSIC researcher Javier Tamayo, who works at the Institute of Microelectronics in Madrid.
“The biosensor uses structures which are manufactured using well-established microelectronics technology, thus making large scale, low cost production possible. This, combined with its simplicity, could make it a great choice for use in developing countries”, notes Tamayo.
How the biosensor works
The experiment begins by incubating one millilitre of human serum on the sensor for one hour at 37 °C to allow binding of any existing HIV-1 p24 antigens to the capture antibodies located on the sensor’s surface. Next, it is re-incubated at 37 °C, though in this case with gold nanoparticles, for 15 minutes so the captured p24 proteins can be marked.
Finally, the resulting material is rinsed to remove any unbound particles. “The test takes a total of 4 hours 45 minutes, which is really rapid. In fact, to confirm the diagnosis you could even repeat the test and the clinical results could be back on the same day as the medical examination. The results are statistically significant and could be adapted to medical requirements”, explains the CSIC researcher.
HIV detection systems
Acute human immunodeficiency virus infection is defined as the time from virus acquisition to seroconversion, i.e. the onset of detectable antibodies to HIV in the blood.Today there are two ways to detect HIV in the blood. Firstly, infection can be diagnosed by detecting viral RNA in the blood using nucleic acid amplification tests (NAAT), and secondly by detecting p24 protein with fourth generation immunoassays.
The first method, based on detecting viral RNA in the blood, has a detection limit of 20 to 35 copies of RNA per millilitre, i.e. a concentration typically occurring two weeks after HIV acquisition. In the second method, during the fourth generation immunoassays, a detection threshold of p24 in 10 picograms per millilitre is reached. This occurs approximately three to four weeks after infection.
“This new technology is capable of detecting p24 at concentrations up to 100,000 times lower than the previous generation of approved immunoassays methods and 100 times lower than methods for detecting viral RNA in blood. This reduces the undetectable phase after infection to just one week”, says CSIC researcher Priscila Kosaka from Madrid’s Institute of Microelectronics.
Detecting HIV in blood
The period between infection and seroconversion is approximately four weeks. The early detection of HIV is crucial to improving a person’s health. Progressive changes occur after HIV acquisition, such as irreversible depletion of gut CD4 lymphocytes, replication in the central nervous system, and the establishment of latent HIV reservoirs.
“The potential for HIV infectivity in the first stage of infection is much higher than in the later stages. Therefore, initiating antiretroviral therapy prior to seroconversion improves immune control and has been associated with benefits in CD4 cell count, a reduction in systemic inflammation, the preservation of cognitive function, and a reduction of the latent reservoir. Logically, its detection is critical to the prevention of HIV transmission”, explains Kosaka.
Patented by CSIC, this technology has been licensed to the Mecwins company (a CSIC spin-off) created in 2008 by Javier Tamayo and Montserrat Calleja, and current owner of three patents which represent the fruit of the CSIC researchers’ labour. This recent research has received funding from the Spanish Cancer Association.
Priscila M. Kosaka, Valerio Pini, Montserrat Calleja and Javier Tamayo. Ultrasensitive detection of HIV-1 p24 antigen by a hybrid nanomechanical-optoplasmonic platform with potential for detecting HIV-1 at first week after infection. PLOS ONE.
Kosaka, P. M.; Pini, V.; Ruz, J.; Da Silva, R.; González, M.; Ramos, D.; Calleja, M.; Tamayo, J., Detection of cancer biomarkers in serum using a hybrid mechanical and optoplasmonic nanosensor. Nature Nanotechnology 2014, 9 (12), 1047-1053.
Patente ES2553027 A1. Tamayo de Miguel, Francisco Javier; Monteiro Kosaka, Priscila; Pini, Valerio; Calleja, Montserrat ; Ruz Martínez, José Jaime ; Ramos Vega, Daniel ; González Sagardoy, María Ujué. System for biodetection applications.
By: EurekAlert!, USA
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Deep learning-based system could be further developed for smartphones, increasing access to screening and aiding early detection of cancers
Computers can classify skin cancers as successfully as human experts, according to the latest research attempting to apply artificial intelligence to health.
The US-based researchers say the new system, which is based on image recognition, could be developed for smartphones, increasing access to screening and providing a low-cost way to check whether skin lesions are cause for concern.
“We hope that this is a first step towards early detection,” said Andre Esteva, an electrical engineering PhD student from Stanford University and co-author of the research.
According to the World Health Organisation, skin cancer accounts for one in every three cancers diagnosed worldwide, with global incidence on the rise.
In the UK alone, 131,772 cases of non-melanoma skin cancer were recorded in 2014. In the same year there were 15,419 new cases of the deadliest skin cancer, melanoma, making it the fifth most common cancer, according to Cancer Research UK.
As the disease is often initially spotted by a visual examination, Esteva teamed up with colleagues in fields ranging from dermatology to artificial intelligence to create a computer system that would aid screening.
Their approach, described in the journal Nature, is based on deep learning – a class of algorithms used for artificial intelligence. When fed with a large set of ready-sorted data these algorithms pick out and “learn” patterns and relationships. Once trained, the algorithms can then be used to categorise new, unsorted data.
To create the system, the team harnessed a deep learning algorithm built by Google that had already been presented with 1.28 million images of objects such as cats, dogs and cups. Esteva and colleagues then fed the system more than 127,000 clinical images of skin lesions, each already labelled, encompassing many different skin diseases.
Once trained, the team then tested the system’s ability to classify skin cancer by presenting it with just under 2,000 previously unseen images of skin lesions, whose nature had previously been determined by biopsy, and further compared the results for nearly 400 of the images against the judgement of at least 21 dermatologists.
The results reveal that the system is on a par with – if not better than – the experts in telling apart carcinomas from common benign skin growths and melanomas from moles.
For melanomas, the average dermatologist classified around 95% of malignant lesions and 76% of harmless moles correctly. By comparison, the algorithm is capable of correctly classifying 96% of malignant lesions, and correspondingly 90% of benign lesions.
“The aim is absolutely not to replace doctors nor to replace diagnosis,” said Esteva. “What we are replicating [is] sort of the first two initial screenings that a dermatologist might perform.”
While Esteva and colleagues admit the system needs further testing in clinical settings they believe the approach has great promise, suggesting it could be applied to a host of other medical fields.
Boguslaw Obara, a computer scientist at Durham University and expert in image processing, said that the size and complexity of the dataset used to train the system was impressive. The work, he adds, shows we are likely to see algorithms cropping up more and more in everyday life.
Dr Anjali Mahto, consultant dermatologist and spokesperson for the British Skin Foundation also welcomed the research. “This is an exciting new technology that has the potential to increase access to dermatology at a time where there is a national shortage in this speciality and the rates of skin cancer continue to rise,” she said.
But, Mahto warned, the system will need to be carefully assessed for its benefits before it can be rolled out. The approach is also unlikely to replace the role of dermatologists, she adds, pointing out that during a full-body examination experts often discover skin cancer at different sites to those that initially concerned the patient. “There is therefore a possibility that if you rely on people to self-report what they are worried about, other skin cancers – particularly in hard to see sites, e.g. the back – may be missed,” she said.
By: The Guardian, UK
Source: www.theguardian.comRead More
Singapore: Australian authorities have just approved a new drugvenetoclax that is touted to have the power to “melt away” certain advanced forms of chronic lymphocytic leukaemia (CLL). Leukemia is the most common type of cancer in Australia, with 1300 people diagnosed each year.
The drug is recommended for patients with relapsed or refractory CLL with 17p deletion – a mutation that makes the disease relatively resistant to standard treatment options – as well as for patients with relapsed or refractory CLL for whom no other treatment options are available.
Venetoclax was discovered and developed with scientists from US pharmaceutical companies AbbVie and Genentech, as part of an international collaboration with the Walter and Eliza Hall Institute. The first clinical trials for venetoclax started in Melbourne at the Institute’s Victorian Comprehensive Cancer Centre partners The Royal Melbourne Hospital and Peter MacCallum Cancer Centre and were led by Australian haematologists.
Professor Doug Hilton AO, director, Walter and Eliza Hall Institute of Medical Research expressed excitement on the news of the drug’s approval. He said that the drug will be most importantly benefit patients with limited treatment options.
“The fact that Australians with hard-to-treat chronic lymphocytic leukaemia can now benefit from a drug like venetoclax demonstrates how critically important medical research is to the health of our community,” Professor Hilton said.
“TGA approval of venetoclax is a major milestone in a journey spanning decades of powerful and innovative research by teams of leading scientists, clinicians and entrepreneurs, including more than one hundred researchers at Melbourne’s Walter and Eliza Hall Institute of Medical Research.”
Professor Andrew Roberts, a clinical haematologist at The Royal Melbourne Hospital and cancer researcher at the Walter and Eliza Hall Institute and the University of Melbourne, said venetoclax was being combined now with other approved drugs and undergoing phase 2 and phase 3 clinical trials in other blood cancers.
“The hope is that venetoclax, potentially in combination with other approved drugs, could benefit more patients including those with other hard-to-treat types of blood cancer,” Professor Roberts said. “Ongoing research suggests that this drug will be very active against other cancers, so this milestone may just be the beginning.”
By: BioSpectrum, Asia
Source: www.biospectrumasia.comRead More