There’s a reason why farmers wear protective gear when applying organophosphate pesticides. The substances are very effective at getting rid of unwanted bugs, but they can also make people sick. Related compounds – organophosphate nerve agents – can be used as deadly weapons. Now researchers have developed a wearable, flexible biosensor glove that can rapidly detect toxic nerve agents with the touch of a finger. The so-called ‘lab-on-a-glove’ could help improve both defence and food security measures.

The researchers was led by nanoengineering professor Joseph Wang at the University of California San Diego. The biosensor glove is one of the latest technologies coming out of the UC San Diego Center for Wearable Sensors, which is directed by Wang.

Organophosphate nerve agents, including sarin and VX, are highly toxic and can prevent the nervous system from working properly. Organophosphate pesticides are far less potent but work in a similar way and can cause illness in people who are exposed to them, according to the U.S. Centers for Disease Control and Prevention. Detecting either type of these sets of compounds accurately and quickly could help improve both defence and food security measures. So, Wang and colleagues set out to develop a wearable sensor that could meet the requirements of field detection.

The new wearable, flexible glove biosensor carries out the sampling and electrochemical biosensing steps on different fingers, with the thumb finger used for collecting the nerve-agent residues and the index finger containing an enzyme that reacts with organophosphate compounds. A user would swipe the thumb of the glove on a surface for testing, then touch the thumb and index fingers together, creating an electrochemical signal that’s detected by the glove’s electronics. The researchers created stretchable, functional inks to print the collection and sensing elements on these fingers.

For real-time results, the data are sent via a reusable Bluetooth device on the back of the glove to a user’s mobile device. Testing showed that the glove could detect the organophosphate pesticides methyl parathion and methyl paraoxon on various surfaces – including glass, wood and plastic – and on produce. The researchers say the sensor could be used in both security and food safety settings.

UC San Diego ucsdnews.ucsd.edu/pressrelease/lab_on_a_glove_could_bring_nerve_agent_detection_to_a_wearers_fingertips

A synthetic, soft tissue retina developed by an Oxford University student could offer fresh hope to visually impaired people.

Until now, all artificial retinal research has used only rigid, hard materials. The new research, by Vanessa Restrepo-Schild, a 24-year-old doctoral student and researcher at Oxford University’s Department of Chemistry, is the first to successfully use biological, synthetic tissues, developed in a laboratory environment. The study could revolutionise the bionic implant industry and the development of new, less invasive technologies that more closely resemble human body tissues, helping to treat degenerative eye conditions such as retinitis pigmentosa.

Just as photography depends on camera pixels reacting to light, vision relies on the retina performing the same function. The retina sits at the back of the human eye, and contains protein cells that convert light into electrical signals that travel through the nervous system, triggering a response from the brain, ultimately building a picture of the scene being viewed.

Vanessa Restrepo-Schild led the team in the development of a new synthetic, double-layered retina which closely mimics the natural human retinal process. The retina replica consists of soft water droplets (hydrogels) and biological cell membrane proteins. Designed like a camera, the cells act as pixels, detecting and reacting to light to create a grey scale image. The Colombian native said: The synthetic material can generate electrical signals, which might stimulate the neurons at the back of our eye just like the original retina.’

The study shows that unlike existing artificial retinal implants, the cell-cultures are created from natural, biodegradable materials and do not contain foreign bodies or living entities. In this way the implant is less invasive than a mechanical device, and is less likely to have an adverse reaction on the body. Miss Restrepo-Schild added: The human eye is incredibly sensitive, which is why foreign bodies like metal retinal implants can be so damaging, leading to inflammation and/or scarring. But a biological synthetic implant is soft and water based, so much more friendly to the eye environment.’

Of the motivation behind the ground-breaking study, Miss Restrepo-Schild said: I have always been fascinated by the human body, and want to prove that current technology can be used to replicate the function of human tissues, without having to actually use living cells.

University of Oxford www.ox.ac.uk/news/2017-05-04-oxford-student-creates-first-synthetic-retina

Like many surgeons, Dr. Jason Spector is often faced with the challenge of securely closing the abdominal wall without injuring the intestines. If the process goes awry, there can be serious consequences for patients, including bowel perforations or a hernia at the incision site. Often, repairing these complications requires additional surgeries.
“I’ve done a lot of incisional hernia repairs on people who’ve had two, three, or more hernia repairs,” said Dr. Spector, a professor of surgery (plastic surgery) and of plastic surgery in otolaryngology at Weill Cornell Medicine, an adjunct professor in the Meinig School of Bioengineering and a plastic surgeon at NewYork-Presbyterian/Weill Cornell Medical Center.
Unsatisfied with the existing tools to help prevent these poor outcomes, Dr. Spector turned to his long-time collaborator Dr. David Putnam, an associate professor of biomedical engineering at Cornell University, who works at the Ithaca campus. Dr. Spector asked for material that would be strong enough to protect the intestines from a needle puncture and bendable enough to insert through a laparotomy incision that would quickly dissolve in the body.
As it turned out, Dr. Putnam’s then graduate student Nicole Ricapito had created and was testing a material that met those specifications. In a study the collaborators and their colleagues demonstrated that the compound was strong enough to protect mouse intestines during suturing of the abdomen and quickly dissolved in the body.
The compound is made up of polyethylene glycol, a chemical compound used in laxatives and many personal care products, and dihydroxyacetone (DHA), a natural by-product of the breakdown of glucose in the body. The U.S. Food and Drug Administration has approved the use of DHA in nutritional supplements and spray tanners. The polyethylene glycol lends flexibility to the device and DHA adds strength, Dr. Putnam said. Both break down when exposed to water in the body.
In the study, the material was used in lieu of plastic or metal devices called retractors that surgeons typically use to protect the intestines. Traditional retractors must be removed before the incision is completely closed, leaving the surgeon to carefully make the final stiches without protection for the intestines. But Drs. Spector and Putnam’s device is left behind in the abdominal cavity, allowing the final sutures to be made with protection still in place. The study found that the device dissolved within three hours of the surgery, leaving no scarring or signs of toxicity.
The next step for the collaborators will be to try to replicate the results with further preclinical testing. If further study of the device shows it to be safe and effective, Drs. Spector and Putnam hope to pursue commercial development. Cornell University has filed a patent for the device.

Weill Cornell Medicine
news.weill.cornell.edu/news/2017/07/dissolvable-device-could-make-closing-surgical-incisions-a-cinch

People with multiple sclerosis can show signs of something wrong five years before the onset of disease, much earlier than previously thought, according to a new analysis of health records from people with the condition.

The new research is a first step to identifying red flags to help doctors screen for the disease and start interventions earlier. This could point researchers in a new direction for finding the root cause of the disease.

‘Proving that people with multiple sclerosis have already changed their behaviour in the five years before even the earliest medical recognition of the condition is very important because it means we have to look beyond those five years to understand how it is caused,’ said Helen Tremlett, senior author of the study and a professor in the department of medicine at the Djavad Mowafaghian Centre for Brain Health.

Multiple sclerosis is thought to be an autoimmune disease where the body attacks the protective coating, known as myelin, around brain cells. Once a person is diagnosed with multiple sclerosis, a physician will try to pinpoint the onset of the disease, sometimes known as the patient’s first demyelinating event, and can include problems with vision or motor control.

The researchers examined health records of 14,000 people with multiple sclerosis from B.C., Saskatchewan, Manitoba and Nova Scotia over a 20-year period and compared them to the health records of 72,000 people without the disease. They were looking for something called a prodrome, an early set of symptoms that can indicate the onset of a disease.

Prodromes have been identified for other neurological conditions like Alzheimer’s and Parkinson’s diseases. The recognition of these prodromes has provided clues about how the diseases might begin and has stimulated new research into causes or triggers.

This study of patients from across Canada revealed that there is a phase where people begin to show symptoms before multiple sclerosis is medically recognized. During this phase patients tend to visit their physicians, be admitted to a hospital and fill prescriptions more than the general population.

‘There’s something going on here that makes this population of people unique,’ said Jose Wijnands, first author of the manuscript, a postdoctoral fellow and a Michael Smith Foundation for Health Research trainee.

‘When other degenerative brain diseases have a prodrome, it suggests that something may be happening,’ said Tremlett. ‘We hope to uncover what this might be in multiple sclerosis.’

Going forward, the team of researchers will try to understand why these patients had been using the health-care system differently, and whether there are trends in illnesses reported and prescriptions filled that point to a specific set of symptoms that doctors could use to help identify multiple sclerosis earlier.

University of British Columbia news.ubc.ca/2017/04/21/medical-history-reveals-multiple-sclerosis-begins-to-impact-patients-sooner/

Staphylococcus epidermidis bacteria are a significant health concern for hospitalized infants, children and anyone with implanted medical devices. The bacteria-typically skin dwellers-can infect the bloodstream and cause a life-threatening condition known as sepsis. Between one and three million people a year in the United States are diagnosed with sepsis, and between 15 and 30 percent of them die. Severe bacterial sepsis is characterized by an extreme immune response, inflammation, reduced blood flow, clotting, and organ failure. Methicillin-resistant strains of S. epidermidis (MRSE) cause most sepsis cases. Notably, methicillin resistance rates in S. epidermidis exceed those in the more-familiar S. aureus (MRSA), and methicillin resistance makes MRSE infections difficult to treat.
For decades scientists have thought that S. epidermidis sepsis resulted from an overwhelming immune response to unchanging surface structures on the invading bacteria. Now, National Institutes of Health (NIH) scientists have identified an S. epidermidis toxin (PSM-mec) that is released into the bloodstream and contributes to sepsis. The investigators say this is the first time a toxin from S. epidermidis or closely related bacteria has been linked to sepsis.
In tissue studies using S. epidermidis strains, the group found that the PSM-mec toxin helped the bacteria survive in human blood and resist attack by neutrophils, important immune system fighters. In a mouse model, the toxin significantly increased disease and stimulated the immune response, which worsened the septic infection.
The researchers say clinical studies are needed to assess whether PSM-mec affects sepsis in people and thus can be a target for therapeutics. They also are investigating whether related toxins found in methicillin-susceptible S. epidermidis and S. aureus have a similar function.

NIH’s National Institute of Allergy and Infectious Diseases http://tinyurl.com/ybjgqcud