Ultrasound Responsive Smart Implantable Hydrogels for Targeted Delivery of Drugs: Reviewing Current Practices

Abstract

Over the last two decades, the process of delivering therapeutic drugs to a patient with a controlled release profile has been a significant focus of drug delivery research. Scientists have given tremendous attention to ultrasound-responsive hydrogels for several decades. These smart nanosystems are more applicable than other stimuli-responsive drug delivery vehicles (ie UV-, pH-and thermal-, responsive materials) because they enable more efficient targeted treatment via relatively non-invasive means. Ultrasound (US) is capable of safely transporting energy through opaque and complex media with minimal loss of energy. It is capable of being localized to smaller regions and coupled to systems operating at various time scales. However, the properties enabling the US to propagate effectively in materials also make it very difficult to transform acoustic energy into other forms that may be used. Recent research from a variety of domains has attempted to deal with this issue, proving that ultrasonic effects can be used to control chemical and physical systems with remarkable specificity. By obviating the need for multiple intravenous injections, implantable US responsive hydrogel systems can enhance the quality of life for patients who undergo treatment with a varied dosage regimen. Ideally, the ease of selfdosing in these systems would lead to increased patient compliance with a particular therapy as well. However, excessive literature has been reported based on implanted US responsive hydrogel in various fields, but there is no comprehensive review article showing the strategies to control drug delivery profile. So, this review was aimed at discussing the current strategies for controlling and targeting drug delivery profiles using implantable hydrogel systems.

Stimuli-responsive dynamic hydrogels: design, properties and tissue engineering applications

“…These two effects can be utilized to de-cross-link the polymeric networks. 175 When a hydrogel is designed with reversible cross-linking chemistry or a self-healing system, a trigger-on-demand release system could be envisioned. A zinc-oxide-loaded ultra-stretchable hydrogel was synthesized by polymerizing N , N -dimethylacrylamide (DMA), and methacrylic acid (MAA), which can adhere to the abdominal cavity and provide excellent contrast for ultrasound imaging of changes in organ size.…”

Recent Advances in Stimuli-Responsive Doxorubicin Delivery Systems for Liver Cancer Therapy

“…Generally, ultrasound waves have applications in different fields, such as in vivo imaging, physiotherapy, cosmetics and food industry [ 216 ]. In general, release systems based on ultrasound waves are obtained from polymers, in different forms, such as polymer-coated bubbles/emulsions, and polymer hydrogels [ 216 , 217 , 218 , 219 , 220 ]. It was reported that ultrasonic-responsive drug delivery systems are able to increase drug delivery, but also increase the therapeutic efficacy, and temporal release of drugs [ 221 ].…”

Injectable smart stimuli-responsive hydrogels: pioneering advancements in biomedical applications

“…Hydrogels are three-dimensional water-swollen networks with hydrophilic nature crosslinked by various hydrophilic polymers via chemical covalent bonds, physical non-covalent bonds or a combination of both. [1][2][3][4] Meanwhile, hydrogels could be further classified as natural, synthetic or hybrid Wei Huang Prof. Wei Huang serves as the Director of the Department of Orthopedics at the First Affiliated Hospital of Chongqing Medical University, where he also holds the position of Director of the Orthopedics Laboratory. Additionally, he holds the position of Vice President of the Orthopedic Physicians Branch of the Chinese Medical Association.…”

“…Hydrogels are three-dimensional water-swollen networks with hydrophilic nature crosslinked by various hydrophilic polymers via chemical covalent bonds, physical non-covalent bonds or a combination of both. 1–4 Meanwhile, hydrogels could be further classified as natural, synthetic or hybrid based on the source of constituting materials. 4–6 Due to their excellent biocompatibility, extracellular matrix (ECM)-like structure and immensely tunable properties (modified through physical/chemical methods) for specific applications, hydrogels are one of the most widely utilized soft biomaterials in tissue engineering (providing mechanical support and scaffold for tissue regeneration, transporting drugs/cells/cytokines/bioactive molecules, etc .).…”