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Rheumatoid arthritis (RA) is a debilitating autoimmune disease that causes chronic pain and serious complications, presenting a significant challenge to treat. Promising approaches for treating RA involve signaling pathways modulation and targeted therapy. To this end, a multifunctional nanosystem, TPC‐U@HAT, has been designed for RA therapy, featuring multitargeting, dual‐stimuli response, and on‐demand drug release capabilities. TPC‐U@HAT is composed of a probe/prodrug TPC, a JAK1 kinase inhibitor upadacitinib, and the drug carrier HAT. TPC is composed of an aggregation‐induced emission (AIE)‐active NIR‐II chromophore TPY and an NF‐κB/NLRP3 inhibitor caffeic acid phenethyl ester (CAPE), connected via boronic ester bond which serves as the reactive‐oxygen‐species‐responsive linker. The carrier, HAT, is created by grafting bone‐targeting alendronate and hydrophobic tocopheryl succinate onto hyaluronic acid chains, which can encapsulate TPC and upadacitinib to form TPC‐U@HAT. Upon intravenous injection into mice, TPC‐U@HAT accumulates at inflamed lesions of RA through both active and passive targeting, and the overexpressed hyaluronidase and H2O2 therein cleave the hyaluronic acid polymer chains and boronate bonds, respectively. This generates an AIE‐active chromophore for detection and therapeutic evaluation of RA via both optoacoustic imaging and NIR‐II fluorescent imaging and concomitantly releases CAPE and upadacitinib to exert efficacious therapy by inhibiting NF‐κB/NLRP3 and JAK‐STAT pathways. [ABSTRACT FROM AUTHOR]

Abstract Rheumatoid arthritis (RA) is a debilitating autoimmune disease that causes chronic pain and serious complications, presenting a significant challenge to treat. Promising approaches for treating RA involve signaling pathways modulation and targeted therapy. To this end, a multifunctional nanosystem, TPC‐U@HAT, has been designed for RA therapy, featuring multitargeting, dual‐stimuli response, and on‐demand drug release capabilities. TPC‐U@HAT is composed of a probe/prodrug TPC, a JAK1 kinase inhibitor upadacitinib, and the drug carrier HAT. TPC is composed of an aggregation‐induced emission (AIE)‐active NIR‐II chromophore TPY and an NF‐κB/NLRP3 inhibitor caffeic acid phenethyl ester (CAPE), connected via boronic ester bond which serves as the reactive‐oxygen‐species‐responsive linker. The carrier, HAT, is created by grafting bone‐targeting alendronate and hydrophobic tocopheryl succinate onto hyaluronic acid chains, which can encapsulate TPC and upadacitinib to form TPC‐U@HAT. Upon intravenous injection into mice, TPC‐U@HAT accumulates at inflamed lesions of RA through both active and passive targeting, and the overexpressed hyaluronidase and H2O2 therein cleave the hyaluronic acid polymer chains and boronate bonds, respectively. This generates an AIE‐active chromophore for detection and therapeutic evaluation of RA via both optoacoustic imaging and NIR‐II fluorescent imaging and concomitantly releases CAPE and upadacitinib to exert efficacious therapy by inhibiting NF‐κB/NLRP3 and JAK‐STAT pathways.

The development of stimuli-responsive polymeric micelles for targeted drug delivery has attracted much research interest in improving therapeutic outcomes. This study designs copolymers responsive to ultraviolet (UV) light and glutathione (GSH). A disulfide linkage is positioned between a hydrophilic poly(ethylene glycol) monomethyl ether (mPEG) and a hydrophobic o-nitrobenzyl methacrylate (ONBMA) to yield amphiphilic copolymers termed mPEG-SS-pONBMA. Three copolymers with different ONBMA lengths are synthesized and formulated into micelles. An increase in particle size and a decrease in critical micelle concentration go together with increasing ONBMA lengths. The ONB cleavage from mPEG-SS-pONBMA-formed micelles results in the transformation of hydrophobic cores into hydrophilic ones, accelerating drug release from the micelles. Obvious changes in morphology and molecular weight of micelles upon combinational treatments account for the dual-stimuli responsive property. Enhancement of a cell-killing effect is clearly observed in doxorubicin (DOX)-loaded micelles containing disulfide bonds compared with those containing dicarbon bonds upon UV light irradiation. Collectedly, the dual-stimuli-responsive mPEG-SS-pONBMA micelle is a better drug delivery carrier than the single-stimuli-responsive mPEG-CC-pONBMA micelle. After HT1080 cells were treated with the DOX-loaded micelles, the high expression levels of RIP-1 and MLKL indicate that the mechanism involved in cell death is mainly via the DOX-induced necroptosis pathway. [ABSTRACT FROM AUTHOR]

A series of stimuli-responsive star-like block copolymers are synthesized via the combination of reversible addition, fragmentation chain transfer (RAFT) polymerization, and photo-initiated thiol-ene (PITE) click reaction. The controllable block ratio and block sequence, narrow distribution of molecular weight, and customized arm numbers of the star-shaped copolymers reveal the feasibility and benefits of combination of RAFT polymerization and PITE click reaction for synthesis of well-defined star-like (co)polymers. A clear insight into the relationship among the arm number, block sequence, and block ratio of the star-like block copolymers and their stimuli-responsive aggregation behavior was achieved via dynamic light scattering and UV-vis spectroscopy study. Notably, the star-like poly(acrylic acid)-b-poly(2-(dimethylamino) ethyl methacrylate) (star-PAA-b-PDMAEMA) shows higher lower critical solution temperature (LCST) compared to star-PDMAEMA-b-PAA with the same arm number and block ratio due to the inner charged PAA segments at pH > IEP. In addition, for star-like PAA-b-PDMAEMA, higher PAA content enhances the hydrophilicity of the polymer in basic solution and leads to the LCST increase, except for star-PAA1-b-PDMAEMA4 at pH = 9.0 (≈ IEP). For star-PDMAEMA-b-PAA, the PAA content shows minimal effect on their LCSTs, except for the polymer in solution with pH = 9.5, which is far from their IEP. The star-like block copolymers with well-defined structure and tunable composition, especially the facile-controlled block sequence, bring us a challenging opportunity to control the stimuli-responsive properties of star-like block copolymers. [ABSTRACT FROM AUTHOR]

The development of stimuli-responsive polymeric micelles for targeted drug delivery has attracted much research interest in improving therapeutic outcomes. This study designs copolymers responsive to ultraviolet (UV) light and glutathione (GSH). A disulfide linkage is positioned between a hydrophilic poly(ethylene glycol) monomethyl ether (mPEG) and a hydrophobic o-nitrobenzyl methacrylate (ONBMA) to yield amphiphilic copolymers termed mPEG-SS-pONBMA. Three copolymers with different ONBMA lengths are synthesized and formulated into micelles. An increase in particle size and a decrease in critical micelle concentration go together with increasing ONBMA lengths. The ONB cleavage from mPEG-SS-pONBMA-formed micelles results in the transformation of hydrophobic cores into hydrophilic ones, accelerating drug release from the micelles. Obvious changes in morphology and molecular weight of micelles upon combinational treatments account for the dual-stimuli responsive property. Enhancement of a cell-killing effect is clearly observed in doxorubicin (DOX)-loaded micelles containing disulfide bonds compared with those containing dicarbon bonds upon UV light irradiation. Collectedly, the dual-stimuli-responsive mPEG-SS-pONBMA micelle is a better drug delivery carrier than the single-stimuli-responsive mPEG-CC-pONBMA micelle. After HT1080 cells were treated with the DOX-loaded micelles, the high expression levels of RIP-1 and MLKL indicate that the mechanism involved in cell death is mainly via the DOX-induced necroptosis pathway.

Abstract: Two poly(2-(dimethylamino)ethyl methacrylate)-b-poly(acrylic acid) diblock copolymers, PDMAEMA84-b-PAA18 and PDMAEMA50-b-PAA18, were synthesized by the atom transfer radical polymerization (ATRP) and their dual-stimuli responsive behaviors to the changes in temperature and pH in aqueous solutions were investigated by UV–vis spectroscopy, dynamic light scattering (DLS), 1H NMR spectroscopy and surface tension measurement. Different from PDMAEMA84-b-PAA18 solutions where no aggregation is observed between pH 7.0 and 9.5, the PDMAEMA50-b-PAA18 aggregates can exist in this broad pH range due to the hydrophobic interactions among the charge-balanced polyampholyte chains. At high pH, e.g., 11.0, the DMAEMA segments collapse to form the core of micelles due to the hydrophobic property of the de-protonized DMAEMA stabilized with the highly ionized AA segments on the surface of the micelles upon heating. At pH around the IEP, e.g., 9.5, large micelles can be formed in PDMAEMA84-b-PAA18 solution upon heating, just like that at pH 11.0, while PDMAEMA50-b-PAA18 first formed the micelles due to the electrostatic attraction between ionized AA segments and protonated DMAEMA segments, but the aggregation of the micelles was hardly happened upon heating due to the smaller DMAEMA segment. Moreover, LCST can be exactly estimated by surface tension experiment. [Copyright &y& Elsevier]