pH/ROS-responsive propelled nanomotors for the active treatment of renal injury

Hibernating/Awakening Nanomotors Promote Highly Efficient Cryopreservation by Limiting Ice Crystals

The disruptions caused by ice crystal formation during the cryopreservation of cells and tissues can cause cell and tissue damage. Thus, preventing such damage during cryopreservation is an important but challenging goal. Here, a hibernating/awakening nanomotor with magnesium/palladium covering one side of a silica platform (Mg@Pd@SiO2) is proposed. This nanomotor is used in the cultivation of live NCM460 cells to demonstrate a new method to actively limit ice crystal formation and enable highly efficient cryopreservation. Cooling Mg@Pd@SiO2 in solution releases Mg2+/H2 and promotes the adsorption of H2 at multiple Pd binding sites on the cell surface to inhibit ice crystal formation and cell/tissue damage; additionally, the Pd adsorbs and stores H2 to form a hibernating nanomotor. During laser-mediated heating, the hibernating nanomotor is activated (awakened) and releases H2, which further suppresses recrystallization and decreases cell/tissue damage. These hibernating/awakening nanomotors have great potential for promoting highly efficient cryopreservation by inhibiting ice crystal formation.

Megalin-targeting and ROS-responsive elamipretide-conjugated polymeric prodrug for treatment of acute kidney injury

Acute kidney injury (AKI) is associated with both kidney function loss and increased mortality. In the pathological progression of ischemia-reperfusion-induced AKI, the surge of reactive oxygen species (ROS) plays a crucial role. To combat this, mitochondrial-targeted antioxidant therapy shows great promise as mitochondria are the primary source of ROS in AKI. However, most strategies aiming to target mitochondria directly result in nanodrugs that are too large to pass through the glomerular system and reach the renal tubules, which are the main site of damage in AKI. This study focused on synthesizing a Megalin receptor-targeted polymeric prodrug, low molecular weight chitosan-thioketal-elamipretide (LMWC/TK/Ela), to mitigate excessive ROS in renal tubular epithelial cells for AKI. This soluble polymeric prodrug has the ability to successfully reach the tubular site by crossing the glomerular barrier. Once there, it can responsively release elamipretide, which possesses excellent antioxidative properties. Therefore, this research offers a novel approach to actively target renal tubular epithelial cells and intracellular mitochondria for the relief of AKI.

Organic nanomotors: emerging versatile nanobots

Artificial nanomotors are self-propelled nanometer-scaled machines that are capable of converting external energy into mechanical motion. A significant progress on artificial nanomotors over the last decades has unlocked the potential of carrying out manipulatable transport and cargo delivery missions with enhanced efficiencies owing to their stimulus-responsive autonomous movement in various complex environments, allowing for future advances in a large range of applications. Emergent kinetic systems with programmable energy-converting mechanisms that are capable of powering the nanomotors are attracting increasing attention. This review highlights the most-recent representative examples of synthetic organic nanomotors having self-propelled motion exclusively powered by organic molecule- or their aggregate-based kinetic systems. The stimulus-responsive propulsion mechanism, motion behaviors, and performance in antitumor therapy of organic nanomotors developed so far are illustrated. A future perspective on the development of organic nanomotors is also proposed. With continuous innovation, it is believed that the scope and possible achievements in practical applications of organic nanomotors with diversified organic kinetic systems will expand.

H2O2-stimulated Janus-shaped self-propelled nanomotors as an active treatment for acute renal injury

As emerging nanosystems, nanomotors have been applied in the active treatment of many diseases. In this paper, Pt@chitosan-loaded melatonin asymmetrical nanomaterials embedded with L-serine (S, kidney injury molecule 1-targeting agent) were constructed to alleviate acute kidney injury (AKI). The Janus nanocarriers arrived at the renal injury site via the bloodstream and exhibited high permeability. Because of melatonin distribution in the kidneys combined with H2O2-stimulated O2 release, the administration of the Janus nanosystem resulted in active treatment through the motion of nanomotors by asymmetrical O2 release.

Endogenous stimuli-responsive drug delivery nanoplatforms for kidney disease therapy

Kidney disease is one of the most life-threatening health problems, affecting millions of people in the world. Commonly used steroids and immunosuppressants often fall exceptionally short of outcomes with inescapable systemic toxicity. With the booming research in nanobiotechnology, stimuli-responsive nanoplatform has come an appealing therapeutic strategy for kidney disease. Endogenous stimuli-responsive materials have shown profuse promise owing to their enhanced spatiotemporal control and precise to the location of the lesion. This review focuses on recent advances stimuli-responsive drug delivery nano-architectonics for kidney disease. First, a brief introduction of pathogenesis of kidney disease and pathological microenvironment were provided. Then, various endogenous stimulus involved in drug delivery nanoplatforms including pH, ROS, enzymes, and glucose were categorized based on the pathological mechanisms of kidney disease. Next, we separately summarized literature examples of endogenous stimuli-responsive nanomaterials, and outlined the design strategies and response mechanisms. Finally, the paper was concluded by discussing remaining challenges and future perspectives of endogenous stimuli-responsive drug delivery nanoplatform for expediting the speed of development and clinical applications.