Orange‐Emissive Carbon Quantum Dots: Toward Application in Wound pH Monitoring Based on Colorimetric and Fluorescent Changing

Monitoring of wound pH is critical for interpreting wound status, because early identification of wound infection or nonhealing wounds is conducive to administion of therapies at the right time. Here, novel orange‐emissive carbon quantum dots (O‐CDs) are synthesized via microwave‐assisted heating of 1,2,4‐triaminobenzene and urea aqueous solution. The as‐prepared O‐CDs exhibit distinctive colorimetric response to pH changing, and also display pH‐sensitive fluorescence. Benefiting from the response of O‐CDs over a wound‐relevant pH range (5–9), medical cotton cloth is selected to immobilize O‐CDs through hydrogen bond interactions, the resultant O‐CDs‐coated cloth with emission at 560 nm shows a high response to pH variation in the range of 5–9 via both fluorescence and visible colorimetric changes. Moreover, the sensitivity of fluorescence to pH is capable of establishing an analytical mode for determining pH value. Further, the O‐CDs‐based pH indicator possesses not only superior biocompatibility and drug compatibility but also excellent resistance leachability and high reversibility. Importantly, the usage of O‐CDs‐coated cloth to detect pH is free from the interference of blood contamination and long‐term storage, thus providing a valuable strategy for wound pH monitoring through visual response and quantitative determination.     

Smart Bandage for Monitoring and Treatment of Chronic Wounds

Chronic wounds are a major health concern and they affect the lives of more than 25 million people in the United States. They are susceptible to infection and are the leading cause of nontraumatic limb amputations worldwide. The wound environment is dynamic, but their healing rate can be enhanced by administration of therapies at the right time. This approach requires real‐time monitoring of the wound environment with on‐demand drug delivery in a closed‐loop manner. In this paper, a smart and automated flexible wound dressing with temperature and pH sensors integrated onto flexible bandages that monitor wound status in real‐time to address this unmet medical need is presented. Moreover, a stimuli‐responsive drug releasing system comprising of a hydrogel loaded with thermo‐responsive drug carriers and an electronically controlled flexible heater is also integrated into the wound dressing to release the drugs on‐demand. The dressing is equipped with a microcontroller to process the data measured by the sensors and to program the drug release protocol for individualized treatment. This flexible smart wound dressing has the potential to significantly impact the treatment of chronic wounds.     

Feasibility study of polyurethane shape-memory polymer actuators for pressure bandage application

Abstract

The feasibility of laboratory-synthesized polyurethane-based shape-memory polymer (SMPU) actuators has been investigated for possible application in medical pressure bandages where gradient pressure is required between the ankle and the knee for treatment of leg ulcers. In this study, using heat as the stimulant, SMPU strip actuators have been subjected to gradual and cyclic stresses; their recovery force, reproducibility and reusability have been monitored with respect to changes in temperature and circumference of a model leg, and the stress relaxation at various temperatures has been investigated. The findings suggest that SMPU actuators can be used for the development of the next generation of pressure bandages.     

Feasibility study of polyurethane shape-memory polymer actuators for pressure bandage application

The feasibility of laboratory-synthesized polyurethane-based shape-memory polymer (SMPU) actuators has been investigated for possible application in medical pressure bandages where gradient pressure is required between the ankle and the knee for treatment of leg ulcers. In this study, using heat as the stimulant, SMPU strip actuators have been subjected to gradual and cyclic stresses; their recovery force, reproducibility and reusability have been monitored with respect to changes in temperature and circumference of a model leg, and the stress relaxation at various temperatures has been investigated. The findings suggest that SMPU actuators can be used for the development of the next generation of pressure bandages.     

An Adhesive Hydrogel with “Load-Sharing” Effect as Tissue Bandages for Drug and Cell Delivery

Hydrogels with adhesive properties have potential for numerous biomedical applications. Here, the design of a novel, intrinsically adhesive hydrogel and its use in developing internal therapeutic bandages is reported. The design involves incorporation of “triple hydrogen bonding clusters” (THBCs) as side groups into the hydrogel matrix. The THBC through a unique “load sharing” effect and an increase in bond density results in strong adhesions of the hydrogel to a range of surfaces, including glass, plastic, wood, poly(tetrafluoroethylene) (PTFE), stainless steel, and biological tissues, even without any chemical reaction. Using the adhesive hydrogel, tissue-adhesive bandages are developed for either targeted and sustained release of chemotherapeutic nanodrug for liver cancer treatment, or anchored delivery of pancreatic islets for a potential type 1 diabetes (T1D) cell replacement therapy. Stable adhesion of the bandage inside the body enables almost complete tumor suppression in an orthotopic liver cancer mouse model and ≈1 month diabetes correction in chemically induced diabetic mice.     

A Wirelessly Controlled Smart Bandage with 3D‐Printed Miniaturized Needle Arrays

Chronic wounds are one of the most devastating complications of diabetes and are the leading cause of nontraumatic limb amputation. Despite the progress in identifying factors and promising in vitro results for the treatment of chronic wounds, their clinical translation is limited. Given the range of disruptive processes necessary for wound healing, different pharmacological agents are needed at different stages of tissue regeneration. This requires the development of wearable devices that can deliver agents to critical layers of the wound bed in a minimally invasive fashion. Here, for the first time, a programmable platform is engineered that is capable of actively delivering a variety of drugs with independent temporal profiles through miniaturized needles into deeper layers of the wound bed. The delivery of vascular endothelial growth factor (VEGF) through the miniaturized needle arrays demonstrates that, in addition to the selection of suitable therapeutics, the delivery method and their spatial distribution within the wound bed is equally important. Administration of VEGF to chronic dermal wounds of diabetic mice using the programmable platform shows a significant increase in wound closure, re‐epithelialization, angiogenesis, and hair growth when compared to standard topical delivery of therapeutics.     

Novel Making of Bacterial Cellulose Blended Polymeric Fiber Bandages

Bacterial cellulose (BC) is a very promising biological material. However, at present its utilization is limited by difficulties in shape forming it. In this Communication, it is shown how this can be overcome by blending it with poly(methylmethacrylate) (PMMA) polymer. BC:PMMA fibers are produced by pressurized gyration of blended BC:PMMA solutions. Subsequently, BC:PMMA bandage‐like scaffolds are generated with different blends. The products are investigated to determine their morphological and chemical features. Cell culture and proliferation tests are performed to obtain information on biocompatibility of the scaffolds.