More than 230 million major surgeries are performed worldwide every year. In surgery, doctors primarily use surgical sutures (or surgical needles) to close a wound and connect tissues. Surgical suturing requires a skilled physician, but can still cause tissue retrauma, pain, inflammation, and scarring. In addition, tissues and organs such as the colon, esophagus, airways and lungs connected with surgical sutures (needles) have a risk of re-leakage of up to 30%. In the United States, secondary leaks from fusion procedures cost patients billions of dollars each year for a wide variety of patients. Therefore, there is an urgent need to develop a reliable method for connecting human tissues. Bioglue has the potential to replace and help surgical sutures (needles), but existing bioglue still has low bond strength, slow bonding speed, poor biocompatibility, incompatibility with tissue mechanical properties, and inconvenient storage and use.

MIT Zhao Xuanhe's team pioneered the application of double-sided human body tape (fabric double-sided tape), which can firmly bond various soft and wet tissues in the body and implanted devices within 5 seconds, maintaining high adhesive strength, high flexibility, and high bioactivity for a long time. Compatibility, eventually biodegradable. Live animal experiments show that human double-sided adhesive tape is expected to replace surgical sutures (needles), fasten human tissues together easily and quickly, and implant medical devices in the body. In addition, the human body double-sided tape is a continuous tape, which is very convenient to store and use.

October 31, 2019 Beijing time, Nature published an article titled "Dry Double-sided Tape for Adhering Wet Fabrics and Devices".

MIT official introduction

Adhesive mechanism of human body double-sided tape

The team at MIT Zhao Xuanhe pioneered a dry-stitching mechanism for quickly and firmly bonding a variety of wet surfaces (wet adhesion). The main difficulty in bonding wet surfaces is the interference of moisture on the surface of the material when interacting between surfaces. Traditional bioadhesives rely on the diffusion of adhesion molecules (usually polymers) in water to achieve tissue adhesion, which takes at least several minutes. In contrast, human double-sided adhesive tape can absorb moisture on the surface of wet tissues within 5 seconds and at the same time form physical bonds and covalent cross-links with tissues (Fig. 1). After absorbing water, the double-sided tape turns into a soft, strong, biocompatible hydrogel that retains a strong bond for days ormonths.

Figure 1. Traditional biological adhesive (left) is based on a diffusion crosslinking mechanism, while human double-sided adhesive (right) is based on a dry crosslinking mechanism.

Morphological characteristics of double-sided tape

Figure 2. Morphological characteristics (left), deformability (center) and stretch-stress curve (right) of human double-sided tape

The human body double-sided adhesive tape is a thin film that has excellent shape adaptability and can be attached to the surface of human organs and tissues of any shape. Depending on the purpose of use, the double-sided adhesive tape for the human body can be processed into various forms, such as regular patch, porous patch, and tape roll. In the hydrogel state, the shear modulus of human double-sided adhesive is 2.5~5kPa, and it can also be stretched to 16 times its original length, which is enough to match the flexibility and extensibility of various human soft tissues (Figure 2). ).

Adhesion characteristics of double-sided adhesive tape

Figure 3. Comparison of adhesive performance between double-sided body tape and various commercial products.

Double-sided body adhesive provides strong, fast, durable and stable adhesion. With light applied pressure (1kPa), double-sided adhesive tape for the human body can provide a shear strength of up to 120kPa and a wet skin adhesion strength of up to 710Jm for 5 seconds. The human body double-sided adhesive can be adhered to various types of organs such as skin, muscle, heart, liver and gastrointestinal tract under dynamic conditions; bonding of various hard materials. The bonding characteristics of human double-sided adhesive are far superior to known biological adhesives, including those based on cyanoacrylate (Cyanoacrylate), albumin (Albumin), polyethylene glycol (Polyethylene glycol), fibrin (Fibrin), etc. Commercial product (Fig. 3).

Double-sided tape and bonding of various materials

Biology of human double-sided tape

Compatibility and degradability

Zhao Xuanhe's team, together with Ellen Roche's team at the Massachusetts Institute of Technology, attached a heart drug patch to the beating heart of a live mouse in 5 seconds, and it remained firmly attached to the beating heart for several days. Double-sided human tape is faster, easier, and more efficient than the existing method of suturing heart patches, and avoids injury caused by sutures. Two weeks after subcutaneous implantation of the human double-sided adhesive in the back of the mouse, no adverse reactions were observed, and the level of inflammatory response reached the standard for products approved by the US Food and Drug Administration (FDA). In addition, the double-sided tape of the human body can be completely degraded in vivo and in vitro. According to different application purposes, Zhao Xuanhe's team can adjust the degradation rate of human double-sided adhesive for days, weeks and months by adjusting the composition ratio of human double-sided adhesive.

Mouse heart getting closer

It is possible to use double-sided adhesive tape for the human body

Zhao Xuanhe's team also demonstrated many possible applications of double-sided adhesive tape for humans. Human double-sided tape can help surgeons seal incisions and heal wounds. In particular, compared with surgical sutures, human double-sided adhesive tape has obvious advantages for relatively soft and fragile organs such as the lungs and trachea, and avoids gastrointestinal leakage caused by imperfect surgical sutures. Secondly, since the human body double-sided adhesive is suitable for various materials other than tissues, it can be used to implant various medical devices into the human body, including devices for repairing organs such as the heart,health monitoring equipment. and sustained release drug carriers. Compared with traditional suture methods, the double-sided human body tape is easy to operate, effectively avoiding the risk of organ damage and complications.

Different use cases

Double-sided tape for modeling the human body

Student Mao Xinyu of Zhao Xuanhe's team has developed a physical model of double-sided tape on the human body that absorbs water. Depending on the water content of various tissues and organs, the water absorption and water absorption time of the double-sided adhesive tape can be predicted. This model helps Zhao Xuanhe's team to develop double-sided adhesives with different properties and thicknesses for various tissues and organs, allowing a wet surface to dry in 5 seconds and providing a fast and strong bond.

Comments

Professor Shrike Zhang, an expert in tissue engineering and 3D bioprinting at Harvard Medical School, commented on this work:

"This is an excellent innovation by Professor Zhao's team, which is essentially a very simple yet extremely effective double-sided fabric adhesive concept. It is fundamentally different from how bio-adhesives are traditionally developed and instead of being implemented starting wet, this double-sided tape starts dry and thin. Interestingly, such a fundamental deviation also goes well with a fundamental improvement - once the tape is applied to the target wound site, the wetting process, which simultaneously removes water molecules from the tissue surface, causes an almost instantaneous strong physical bond. which develops over time into a stable chemical bond via embedded reactive groups as the swelling of the tape continues to develop into a piece of biocompatible, biodegradable, water rich formyl hydrogel.Its dual mesh nature remains mechanically strong, allowing perfect wound healing until it heals. Ogro There is great potential for this elegant approach to be applied in various clinical practices as well as in basic engineering applications, especially in situations where surgical procedures such as suturing are not straightforward.”

Costantino Creton, director of ESPCI France and an expert in adhesion, commented on double-sided adhesive tape for the human body:

"By combining two innovative concepts, the research team was able to quickly and effectively adhere to a damp and soft tissue surface, and maintain good adhesion and mechanical properties for several days without causing an excessive inflammatory response."

Author's perspective

Based on the new dry stitching mechanism, the human body double-sided adhesive can quickly and firmly bond a variety of internal tissues and medical devices, maintain high adhesive strength, high flexibility, high biocompatibility for a long time and, ultimately, biodegradable. Therefore, it has great potential compared to traditional bioadhesives and is a potential replacement for surgical sutures. The double-sided adhesive tape for the human body has excellent adhesive properties, flexibility, biocompatibility, degradability and long-term storage. In addition, human double-sided adhesive tape opens up new possibilities in the field of biological scaffolds, sustained release drugs, wearable and implantable medical devices. The drying mechanism of human double-sided adhesive also points to a new direction for the development of a new generation of new adhesive materials that can be used in humid environments and underwater.

team view

The work was led by the team of Zhao Xuanhe from the Massachusetts Institute of Technology. Corresponding author Dr. Xuanhe Zhao is a tenured professor at the Massachusetts Institute of Technology. The first author of this paper is Zhao Xuanhe's team. Graduate student Hyeonwu Yuk and MIT PhD student Claudia E. Varela. Other contributors include Christoph S. Nabzdik, Xinyu Mao, Robert F. Padera, and Ellen T. Roche.

Zhao Xuanhe's team at the Massachusetts Institute of Technology (http://zhao.mit.edu) is promoting soft materials and human-machine synthesis technologies. Among recent achievements:

Studying the mechanism

Applied Research

Summary