Better Than Staples and Pins – Hot-Glue Gun Fuses Biocompatible Tissue
Hot-glue guns can be used for more than putting together cardboard furniture, home decorations, and toys. In fact, researchers at the Technion–Israel Institute of Technology have developed a hot-glue gun to adhere human tissues that have been seriously injured.
Prof. Boaz Mizrahi
Most serious injuries are currently treated with pins and stitches that have many drawbacks. For the patient, they are very painful, leave scars, require high skill from the doctor, and sometimes have to be removed after the tissues heal. Medical glue, on the other hand, can produce improved medical and cosmetic results.
Such tissue bioadhesives are widely used in dermatology, surgical theaters, and in the field. But even though they have advantages over sutures and staples, currently available tissue glues are limited by their mechanical properties and toxicity. Because they are very toxic, they can be utilized only on the surface of the skin. In addition, hardening of the glue may make the organ less flexible or the adhesion may not be sufficiently strong.
With these limitations in mind, researchers have long been trying to develop a glue that is suitable for different tissues, non-toxic, and flexible after hardening. Such a glue would also need to decompose in the body after the tissue is fused together.
In an article published recently in the journal Advanced Functional Materials, Biomaterials Laboratory headProf. Boaz Mizrahi and doctoral student Alona Shagan introduce a very strong, non-toxic tissue adhesive that remains flexible even after solidification.
Melting the glue and smearing it on the damaged tissue is performed with a hot-glue gun. Unlike the glue guns with which we are familiar, this gun warms the glue to a moderate temperature – just above that of the body – so as not to cause a burn. After the glue is applied, it quickly hardens and decomposes within a few weeks. The adhesive is also suitable for the adhesion of tissue inside the body, and it is four times as strong as existing adhesives used for this purpose. Tested on cells and laboratory animals, it was effective and nontoxic.
Doctoral student Alona Shagan
The new approach is based on a biocompatible, low-melting-point, four‐armed N‐hydroxy succinimide‐modified polycaprolactone (star‐PCL‐NHS). Star‐PCL‐NHS is inserted into a hot-melt glue gun and melts upon minimal pressure, the team wrote. It is squeezed directly onto the wound, where it solidifies, bonding strongly with both edges of the wound. Changes in molecular weight allow control of adhesive strength, melting point, and elasticity properties. In-vitro and in-vivo evaluations confirm the biocompatibility of this system. The straightforward synthetic scheme and the simple delivery method – combined with the desirable mechanical properties, tenability and tissue compatibility – are desirable traits in wound management.
The researchers believe the new concept will lead to the development of devices that will reduce the use of stitches, staples and pins, speed up the healing process and reduce scarring.
Wearable Devices for Medical Diagnosis: An International Conference at the Technion
On May 13-14, the First International Conference on Wearable Devices for Medical Diagnosis was held at the Technion–Israel Institute of Technology in Haifa. Attended by industry and academic personnel from all over the world, the conference was led by Professor Hossam Haick, head of the Nanomaterial-based Devices Laboratory at the Wolfson Chemical Engineering Faculty and a member of the Russell Berrie Nanotechnology Institute (RBNI).
Conference participants
“The field of wearable devices has been gaining momentum in recent years, and today there are wearable diagnostic technologies such as smart watches and smart clothes,” said Prof. Haick. “But they are often inaccurate or limited in the variety of possible applications. The way to leapfrog ahead in this area is biochemical sensing – precise monitoring of physiological conditions based on chemical monitoring of the skin and of various organs. We aim to produce non-invasive – or almost non-invasive – monitoring technologies and to connect the sensors to IOT (Internet of Things) infrastructures, so that multiple data can be collected and analyzed electronically for the benefit of the medical staff.”
Conference lectures focused on a wide range of topics that included pulmonary function monitoring, cardiac activity monitoring, the development of medical monitoring sensors, and innovative skin patches for rapid and inexpensive monitoring of tuberculosis.
Dr. Andrey Broisman, scientific director of engineering at the Ministry of Science and Technology, greeted the conference participants and presented the Ministry’s support channels for Israeli science and international cooperation.
The opening lectures were delivered by Prof. Kenneth Suslick of the University of Illinois and Prof. Corrado di Natale of the University of Rome. Prof. Suslick presented the solutions developed in the last decade in the field of sensors that are likely to play a major role in the diagnosis of diseases by wearable technologies. These include inexpensive sensors that decompose, as well as ones that mimic the natural olfactory system and provide a visual output that describes the object’s odor properties.
“In fact, we developed a system that identifies the ‘molecular fingerprint’ of odors, enabling accurate electronic mapping of the components of odor and monitors toxic gases and spoiled food,” said Prof. Suslick. “They can distinguish among different types of coffee, whiskey, etc. In medicine, we have been able to perform continuous monitoring over time and identify biological markers of heart and kidney disease, and no less importantly, monitor bacterial resistance to medications.”
Prof. di Natale described his approach to electronic monitoring of biochemical materials related to human health. This approach, “combinatorial selectivity,” simulates the natural system of human smell sensing. “A person has about 350 smell sensors that can differentiate among millions of sources of odors,” he said. “Inspired by the human olfactory system, we have developed a technology that makes it possible for us to monitor malaria and cancer and also to distinguish among different types of cancers.”
Ph.D. candidate Muhammad Khatib of the Haick Research Group presented innovative technology in the world of wearable monitoring – flexible sensing systems that can repair themselves.
“When we speak about wearable equipment,” said Mr. Khatib, “we want systems that can stretch and are flexible, but they also must be self-correcting, which we developed with inspiration from nature and the support of the Bill and Melinda Gates Foundation.”
“Animals have the ability to repair damaged tissues in their body, and that is the characteristic that we want to copy,” Mr . Khatib continued. “What we have developed is a polymer-based transistor that can repair itself not only structurally and mechanically, but also in terms of its electrical properties. After we saw that it succeeded in fixing itself when we cut it, we repeated it in various types of water, even seawater, and found that it quickly repairs itself and recovers its previous capabilities. The significance of this is that these devices can work in the damp environment of biological tissue, on sweaty skin, and so forth.”.
The conference was held at a unique time in terms of the international activities of the Nanomaterial-Based Devices Lab, namely the completion of the SniffPhone consortium and the opening of two new clusters: VOGAS and A-Patch. The three consortia are part of the Horizon 2020 program of the European Union, which allocated a total amount of 18 million euro to them.
The SniffPhone system is based on a smartphone-related technology for speedy diagnosis of cancer and other diseases based on the patient’s breath. The new hardware is a system the size of a smartphone into which the patient exhales (without the need to hold it directly on the mouth). The data are transmitted via mobile phone to the “cloud” in which the information is analyzed and the results are transmitted to the attending physician. Vogas, a consortium of academics and industry partners from Europe and Latin America, is continuing the same project for eventual clinical implementation.
A-Patch, a consortium of researchers from academia, hospitals, and various companies, is working for the continued development of a cheap and reliable patch for tuberculosis (TB) surveillance. TB, one of the world’s most infectious and deadly diseases, accounts for about 1.8 million deaths each year.
The current diagnostic method, a skin test, requires laboratory services and takes a long time. The skin test is a process that involves injecting a substance (tuberculin) into one of the arms, testing the skin reaction after a few days and repeating the whole process in the other arm two weeks later. The development on which the new consortium works is a small, inexpensive, disposable diagnostic sticker that will cost about $1.50. A multiple-use sticker will cost about twice as much. The label reads the patient’s physiological data and attaches it to a smartphone. This data is then transferred to the cloud for analysis and diagnosis by a physician. The Bill and Melinda Gates Foundation has been involved with the project for several years.
An artificial black hole provides quantitative confirmation of the temperature and thermality of Hawking radiation
During his distinguished career as a theoretical physicist and cosmologist, the late Stephen Hawking predicted that black holes – invisible and massive phenomena in space with such strong gravity that nothing, even light, can escape its deep, dark grasp – emit radiation. This Hawking radiation should have a thermal spectrum, similar to the radiation from any warm object. The temperature of the Hawking radiation should agree with the temperature predicted by Jacob Bekenstein.
Professor Jeff Steinhauer Photo credit: Technion Spokesperson’s Office
Now, a team of researchers from the Department of Physics at the Technion–Israel Institute of Technology have created an artificial black hole in which sound plays the role of light. By devising a way to measure the spectrum of Hawking radiation, they have found that artificial black holes do emit radiation like an ordinary warm object, as Hawking’s predictions asserted.
A paper explaining their groundbreaking research appeared in the May, 30 2019 issue of Nature.
Almost four decades ago, a theory emerged suggesting artificial black holes could be constructed and used to measure the physics of Hawking radiation, a type of thermal radiation, the existence of which Hawking predicted in the 1970s and which now bears his name. However, it was the task of creating an artificial black hole, and devising ways to measure the spectrum of Hawking radiation and its temperature, that led to the recent breakthrough.
“Our artificial black hole provides confirmation of the thermality of Hawking radiation,” explained lead researcher Professor Jeff Steinhauer. “In addition, we found that the temperature is determined by the artificial gravity at the surface of the artificial black hole, also consistent with Hawking’s predictions.”
The success of their work is yet another profound insight into the nature of black holes, among the most mysterious and least understood secrets of the universe.
The concept of an object in space with gravitation fields too strong for light to escape was considered in the 18th century. The first modern theory about the existence of black holes was developed in 1916, but not fully characterized and considered to be just mathematical curiosities until the late 1960s, when theories were sparked by knowledge about the collapse of massive stars. Although they could not be seen, a consensus was soon reached that black holes existed in most galaxies.
Having studied this phenomenon and problem for a decade, the research team made constant improvements to their experimental tools over the last three years. The goal was to not only create artificial black holes, but also to develop methods to make measurements to check Hawking’s predictions. To reach their conclusions, the Hawking radiation experiment was repeated 7,400 times providing a density profile for each “run”, from which the researchers computed averages.
“Theoretical works, combined with our long-term study of this subject, allowed for the observation of spontaneous Hawking radiation in an artificial black hole,” reported Steinhauer. “The improvements in our experimental apparatus allowed us to measure the thermality of the Hawking spectrum and compare its temperature with Hawkings’ prediction, given by the surface gravity.”
According to the researchers, this temperature (as predicted) provides an interesting link between the theories of Hawking and those of astrophysicist Jacob Bekenstein. In 1972, Bekenstein also presented a theory on black hole thermodynamics.
“Remarkably, although their calculations were based on very different ideas, both Hawking and Bekenstein came up with the same conclusion that the temperature was determined by the gravity at the surface of the black hole,” said Steinhauer. “We confirmed their predictions.”
While the discovery made by the Technion physicists makes clearer the nature of artificial black holes by measuring the spectrum emitted (very similar to the spectrum that would be emitted by an ordinary warm object), the low levels of radiation not only confirm Hawking’s theory, but could also lead to further research.
According to Steinhauer and his team, their findings provide not only hints about the nature of real black holes, but also about the “information paradox.” According to Hawking, the radiation and its thermal spectrum contain very little information. This idea is the basis of the information paradox, which poses questions such as: What is the fate of information that falls into a real black hole? Does it disappear from the universe? And, if not, where does it go?
The researchers found that the spectrum of the Hawking radiation is indeed thermal. So, the information paradox remains unresolved with future researchers needing to look elsewhere to investigate the information paradox enigma.
