Sensing Technologies for Extravasation Detection: A Review.

Peripheral intravenous catheters are administered for various purposes, such as blood sampling or the infusion of contrast agents and drugs. Extravasation happens when the catheter is unintentionally directed outside of the vein due to movement of the intravascular catheter, enhanced vascular permeability, or occlusion of the upstream vein. In this article, extravasation and its mechanism are discussed. Subsequently, the sensorized devices (e.g., single sensor and multimodal detection) to identify the extravasation phenomena are highlighted. In this review article, we have shed light on both physiological and engineering points of view of extravasation and its detection approaches. This review provides an overview on the most recent and relevant technologies that can help in the early detection of extravasation.

Engineering and Development of a Tissue Model for the Evaluation of Microneedle Penetration Ability, Drug Diffusion, Photothermal Activity, and Ultrasound Imaging: A Promising Surrogate to Ex Vivo and In Vivo Tissues.

Driven by regulatory authorities and the ever-growing demands from industry, various artificial tissue models have been developed. Nevertheless, there is no model to date that is capable of mimicking the biomechanical properties of the skin whilst exhibiting the hydrophilicity/hydrophobicity properties of the skin layers. As a proof-of-concept study, tissue surrogates based on gel and silicone are fabricated for the evaluation of microneedle penetration, drug diffusion, photothermal activity, and ultrasound bioimaging. The silicone layer aims to imitate the stratum corneum while the gel layer aims to mimic the water-rich viable epidermis and dermis present in in vivo tissues. The diffusion of drugs across the tissue model is assessed, and the results reveal that the proposed tissue model shows similar behavior to a cancerous kidney. In place of typical in vitro aqueous solutions, this model can also be employed for evaluating the photoactivity of photothermal agents since the tissue model shows a similar heating profile to skin of mice when irradiated with near-infrared laser. In addition, the designed tissue model exhibits promising results for biomedical applications in optical coherence tomography and ultrasound imaging. Such a tissue model paves the way to reduce the use of animals testing in research whilst obviating ethical concerns.

Injectable Antibacterial Gelatin-Based Hydrogel Incorporated with Two-Dimensional Nanosheets for Multimodal Healing of Bacteria-Infected Wounds.

The design and development of multifunctional injectable hydrogels with high photothermal antibacterial activity and shape adaptability to accelerate bacteria-infected wound healing is of critical importance in clinical applications. In this study, a hybrid hydrogel composed of gelatin, iron, and MnO2 nanosheets was prepared by multiple interactions, including coordinative and hydrogen bonding as well as electrostatic attraction. The introduced MnO2 and Fe components made the hydrogels photothermally and chemodynamically active, thereby endowing them with potent antibacterial capabilities against both Gram-negative and Gram-positive bacteria. Because of the Fenton activity of the hydrogels, they could produce abandoned oxygen, which is highly crucial in the healing process of wounds. They also showed good cytocompatibility and hemocompatibility as well as high hemostatic properties. Moreover, the injectable hydrogels could fill irregular wounds and significantly accelerate bacteria-infected wound healing through decreasing the inflammatory response and increasing blood vessels. These features indicated the promising potential of the multifunctional hydrogel for healing infected full-thickness wounds.