An official website of the United States government
Abstract Medical adhesives are vital for securing wearable sensors, wound dressings, and critical medical devices. These adhesives must balance strong adhesion with patient comfort, especially when used over extended periods. Adhesives that maintain their efficacy for more than two weeks are essential for continuous monitoring devices, as they enhance diagnostic accuracy and reduce dressing changes, minimizing patient discomfort and infection risk. However, current long-wear adhesives often use aggressive acrylics that can cause skin injuries. To overcome these limitations, we developed an advanced ThermoTape offering temperature-responsive properties with a polyurethane backing for more than 14 days of wear. A double transfer coating process fabricated PU-ThermoTape, with surface morphology characterized using Atomic Force Microscopy. Differential Scanning Calorimetry and thermography determined the optimal removal window. Peeling strength tests were conducted at room and elevated temperatures to assess performance. In vitro, PU-ThermoTape displayed an average peeling strength of 0.3 N/mm at 25 °C, decreasing by 75% when heated to 45°C, with an optimal removal window of approximately 2.5 minutes. The tape demonstrated excellent skin conformity with its polyurethane backing. In a 14-day wearability study with seven volunteers, PU-ThermoTape outperformed Tegaderm, maintaining temperature-responsiveness and allowing unrestricted daily activities throughout. PU-ThermoTape provides robust adhesion, high skin conformity, and facilitates gentle removal after brief warming, positioning it as a versatile adhesive suitable for various applications with different duration requirements.
more »
« less
Fast, strong, and reversible adhesives with dynamic covalent bonds for potential use in wound dressing
Adhesives typically fall into two categories: those that have high but irreversible adhesion strength due to the formation of covalent bonds at the interface and are slow to deploy, and others that are fast to deploy and the adhesion is reversible but weak in strength due to formation of noncovalent bonds. Synergizing the advantages from both categories remains challenging but pivotal for the development of the next generation of wound dressing adhesives. Here, we report a fast and reversible adhesive consisting of dynamic boronic ester covalent bonds, formed between poly(vinyl alcohol) (PVA) and boric acid (BA) for potential use as a wound dressing adhesive. Mechanical testing shows that the adhesive film has strength in shear of 61 N/cm 2 and transcutaneous adhesive strength of 511 N/cm 2 , generated within 2 min of application. Yet the film can be effortlessly debonded when exposed to excess water. The mechanical properties of PVA/BA adhesives are tunable by varying the cross-linking density. Within seconds of activation by water, the surface boronic ester bonds in the PVA/BA film undergo fast debonding and instant softening, leading to conformal contact with the adherends and reformation of the boronic ester bonds at the interface. Meanwhile, the bulk film remains dehydrated to offer efficient load transmission, which is important to achieve strong adhesion without delamination at the interface. Whether the substrate surface is smooth (e.g., glass) or rough (e.g., hairy mouse skin), PVA/BA adhesives demonstrate superior adhesion compared to the most widely used topical skin adhesive in clinical medicine, Dermabond.
more »
« less
- Award ID(s):
- 1720530
- PAR ID:
- 10414935
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences
- Volume:
- 119
- Issue:
- 29
- ISSN:
- 0027-8424
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Conductive adhesives are required for the integration of dissimilar material components to create soft electronic and robotic systems. Here, a heterogeneous liquid metal‐based conductive adhesive is developed that reversibly attaches to diverse surfaces with high stretchability (>100% strain), low modulus (<100 kPa), and strain‐invariant electrical conductivity. This SofT integrated composite with tacK through liquid metal (STICK‐LM) adhesive consists of a heterogeneous graded film with a liquid metal‐rich side that is embossed at prescribed locations for electrical conductivity and an electrically insulating adhesive side for integration. Adhesion behavior is tuned for adhesion energies > 70 Jm−2(≈ 25x enhancement over unmodified composites) and described with a viscoelastic analysis, providing design guidelines for controllable yet reversible adhesion in electrically conductive systems. The architecture of STICK‐LM adhesives provides anisotropic and heterogeneous electrical conductivity and enables direct integration into soft functional systems. This is demonstrated with deformable fuses for robotic joints, repositionable electronics that rapidly attach on curvilinear surfaces, and stretchable adhesive conductors with nearly constant electrical resistance. This study provides a methodology for electrically conductive, reversible adhesives for electrical and mechanical integration of multicomponent systems in emerging technologies.more » « less
-
Abstract Berries from the European Mistletoe (Viscum album) possess a sticky tissue called viscin that facilitates adhesion and germination onto host trees. Recent studies of viscin have demonstrated its adhesive capacity on a range of natural and synthetic surfaces including wood, skin, metals, and plastic. Yet, the underlying mechanisms remain poorly understood. Here, an investigation of the adhesive performance of mistletoe viscin is performed, demonstrating its hygroscopic nature and ability to self‐heal following adhesive failure. It is identified that adhesion originates from a water‐soluble adhesive component that can be extracted, isolated, and characterized independently. Lap shear mechanical testing indicates that the mistletoe adhesive extract (MAE) outperforms native viscin tissue, as well as gum arabic and arabinogalactan—common plant‐based adhesives. Furthermore, humidity uptake experiments reveal that MAE can reversibly absorb nearly 100% of its mass in water from the atmosphere. In‐depth spectroscopic and mass spectrometry investigations reveal a composition consisting primarily of an atypical arabinogalactan, with additional sugar alcohols. Finally, several proof‐of‐concept applications are demonstrated using MAE for hygro‐responsive reversible adhesion between various surfaces including skin, plastic, PDMS, and paper, revealing that MAE holds potential as a biorenewable and reusable adhesive for applications in cosmetics, packaging, and potentially, tissue engineering.more » « less
-
Abstract Wound closure in surgeries is traditionally achieved using invasive methods such as sutures and staples. Adhesion‐based wound closure methods such as tissue adhesives, sealants, and hemostats are slowly replacing these methods due to their ease of application. Although several chemistries have been developed and used commercially for wound closure, there is still a need for better tissue adhesives from the point of view of toxicity, wet‐adhesion strength, and long‐term bonding. Catechol chemistry has shown great promise in developing wet‐set adhesives that meet these criteria. Herein, we have studied the biocompatibility of a catechol‐based copolymer adhesive, poly([dopamine methacrylamide]‐co‐[methyl methacrylate]‐co‐[poly(ethylene glycol) methyl ether methacrylate]) or poly(catechol‐MMA‐OEG), which is soluble in water. The adhesive was injected subcutaneously in a mouse model on its own and in combination with a sodium periodate crosslinker. After 72 h, 4 weeks, and 12 weeks, the mice were euthanized and subjected to histopathological analysis. Both adhesives were present and still palpable at the end of 12 weeks. The moderate inflammation observed for the poly(catechol‐MMA‐OEG) cohort at 72 h had reduced to mild inflammation at the end of 12 weeks. However, the moderate inflammatory response observed for the poly(catechol‐MMA‐OEG) + crosslinker cohort at 72 h had not subsided at 12 weeks.more » « less
-
Adhesive hydrogels with tunable mechanical properties and strong adhesion to wet, dynamic tissues have emerged as promising materials for tissue repair, with potential applications in wound closure, hemorrhage control, and surgical adhesives. This review highlights the key design principles, material classifications, and recent advances in adhesive hydrogels designed for vascular repair. The limitations of existing adhesive hydrogels, including insufficient mechanical durability, suboptimal biocompatibility, and challenges in targeted delivery, are critically evaluated. Furthermore, innovative strategies—such as incorporating self-healing capabilities, developing stimuli-responsive systems, integrating functional nanocomposites, and employing advanced fabrication techniques like 3D bioprinting—are discussed to enhance adhesion, mechanical stability, and vascular tissue regeneration. While significant progress has been made, further research and optimization are necessary to advance these materials toward clinical translation, offering a versatile and minimally invasive alternative to traditional vascular repair techniques.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1073/pnas.2203074119
