Near-infrared (NIR) irradiation responsive drug delivery systems have many advantages, which have attracted extensive interest from researchers. In this study, a NIR-triggered drug release system was established by grafting upper critical solution temperature (UCST) polymers on the surface of hollow mesoporous silica nanoparticles (HMSNs) followed by treatment with the photothermal conversion agent indocyanine green (ICG). The as-prepared UCST polymers showed the clearing temperature of 45 °C, which were advantageous to serve as gatekeepers in the physiological environment (37 °C). Under NIR irradiation, the temperature of the solution was elevated above the clearing point due to the presence of ICG; consequently, the collapsed UCST polymer chains became more hydrophilic; this resulted in the exposure of the mesoporous channels of the HMSNs and achievement of a burst drug release. Moreover, this NIR-responsive delivery system showed good biocompatibility and high anticancer efficiency towards the MCF-7 cancer cells upon exposure to NIR irradiation. In addition, a synergistic effect of thermal and chemo treatment has been achieved by the application of NIR irradiation since cancer cells are more vulnerable to high temperatures than normal cells.
Dynamic phase transitions are important in living organisms for sustaining their adaptive structures and functions. The design of artificial dynamic systems using light as a noninvasive input fuel has gained significant interest to mimic such adaptive features. Here the development of light-fueled dissipative phase transitions of upper critical solution temperature polymers by introducing pendant spiropyrans as photoactive units, is reported. The reversible open-close photoisomerization of spiropyrans is designed to undergo either an enhancement or a decline of their net charge, which is subsequently used to regulate the electrostatic interactions between polymer chains, and ultimately shift their phase transition temperatures to either a lower or a higher direction. The degree and speed of such bidirectional shifting are flexibly modulated by manipulating the external illumination parameters or varying the compositions/concentrations of the polymers. The diametrically opposite transmittance changes driven by light are utilized to produce a series of complementary patterns and shapes for application in transient information storage and encryption with improved accuracy and security. This work offers a bidirectional spatiotemporal modulation of dissipative phase transitions of polymers using visible light that allows highly tunable and adaptable features shared with their natural counterparts.
Hong Zhang,Xiao Wang,Xiaorong Yang,Zehua Wu,Qin Chen,Qiaolin Wei,Yong Guo,Quan Hu,Jia-Wei Shen
Recent advancements in cancer treatment have underscored the inadequacy of conventional monotherapies in addressing complex malignant tumors. Consequently, there is a growing interest in synergistic therapies capable of overcoming the limitations of monotherapies, leading to more personalized and effective approaches. Among these, the combination of photothermal therapy (PTT) and chemotherapy has emerged as a promising avenue for tumor management. In this study, we present a novel approach utilizing thermoresponsive mesoporous silica nanoparticles (MSN) as a delivery system for the chemotherapeutic drug doxorubicin. By incorporating photothermal agent copper sulfide (CuS) nanoparticles into the MSN, the resulting composite material exhibits potent photothermal properties. Furthermore, the integration of an upper critical solution temperature (UCST) polymer within the silica outer layer serves as a “gatekeeper”, enabling precise control over drug release kinetics. This innovative nanomaterial effectively merges thermoresponsive behavior with PTT, thereby minimizing the collateral damage associated with traditional chemotherapy on healthy tissues. Moreover, in both in vitro studies using mouse breast carcinoma cells (4 T1) and in vivo experiments utilizing a 4 T1 tumor-bearing mouse model, our nanomaterials demonstrated synergistic effects, enhancing the anti-tumor efficacy of combined PTT and chemotherapy. With its remarkable photothermal conversion efficiency, robust stability, and biocompatibility, the UCST-responsive nanoplatform holds immense potential for clinical applications.
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