A pH-UV Dual-Responsive Photoresist for Nanoimprint Lithography That Improves Mold Release

We have developed a degradable photoresist that is responsive to pH and ultraviolet light (UV). This dual-responsive resist consists of 5,7-diacryloyloxy-4-methylcoumarin (fluorescent monomer), acrylic anhydride, and 3,6-dioxa-1,8-dithiooctane. It can be photocured using thiol–acrylate polymerization and photodimerization of coumarin moieties under 365 nm UV light exposure. The cured resist is degradable in aqueous solutions with pH > 7. The degradation process can be characterized by the change of fluorescence intensity in the aqueous solution. In this study, we have analyzed the properties of the degradation of the resist by changing the pH of the solution and its exposure time under 254 nm UV light. This UV exposure can induce photocleavage of the coumarin dimers. We then used these materials to fabricate micropatterns through nanoimprint lithography (NIL) process. Compared with other conventional degradable materials capable of NIL, the dual-responsive resist can help to clean the NIL mold easily at room temperature. This resist is also more environmentally friendly, is relatively low cost, can be faster to degrade, and is easier to characterize. It also has low volume shrinkage, which may have a valuable and positive effect on the development of NIL

A pH-UV Dual-Responsive Photoresist for Nanoimprint Lithography That Improves Mold Release

We have developed a degradable photoresist that is responsive to pH and ultraviolet light (UV). This dual-responsive resist consists of 5,7-diacryloyloxy-4-methylcoumarin (fluorescent monomer), acrylic anhydride, and 3,6-dioxa-1,8-dithiooctane. It can be photocured using thiol–acrylate polymerization and photodimerization of coumarin moieties under 365 nm UV light exposure. The cured resist is degradable in aqueous solutions with pH > 7. The degradation process can be characterized by the change of fluorescence intensity in the aqueous solution. In this study, we have analyzed the properties of the degradation of the resist by changing the pH of the solution and its exposure time under 254 nm UV light. This UV exposure can induce photocleavage of the coumarin dimers. We then used these materials to fabricate micropatterns through nanoimprint lithography (NIL) process. Compared with other conventional degradable materials capable of NIL, the dual-responsive resist can help to clean the NIL mold easily at room temperature. This resist is also more environmentally friendly, is relatively low cost, can be faster to degrade, and is easier to characterize. It also has low volume shrinkage, which may have a valuable and positive effect on the development of NIL

Janus Silver/Silica Nanoplatforms for Light-Activated Liver Cancer Chemo/Photothermal Therapy

Stimuli-triggered nanoplatforms have become attractive candidates for combined strategies for advanced liver cancer treatment. In this study, we designed a light-responsive nanoplatform with folic acid-targeting properties to surmount the poor aqueous stability and photostability of indocyanine green (ICG). In this Janus nanostructure, ICG was released on-demand from mesoporous silica compartments in response to near-infrared (NIR) irradiation, exhibiting predominant properties to convert light to heat in the cytoplasm to kill liver cancer cells. Importantly, the silver ions released from the silver compartment that were triggered by light could induce efficient chemotherapy to supplement photothermal therapy. Under NIR irradiation, ICG-loaded Janus nanoplatforms exhibited synergistic therapeutic capabilities both in vitro and in vivo compared with free ICG and ICG-loaded mesoporous silica nanoparticles themselves. Hence, our Janus nanoplatform could integrate ICG-based photothermal therapy and silver ion-based chemotherapy in a cascade manner, which might provide an efficient and safe strategy for combined liver cancer therapy

Janus Gold Nanoplatform for Synergetic Chemoradiotherapy and Computed Tomography Imaging of Hepatocellular Carcinoma

There is a pressing need to develop nanoplatforms that integrate multimodal therapeutics to improve treatment responses and prolong the survival of patients with unresectable hepatocellular carcinoma (HCC). Mesoporous silica-coated gold nanomaterials have emerged as a novel multifunctional platform combining tunable surface plasmon resonance and mesoporous properties that exhibit multimodality properties in cancer theranostics. However, their reduced radiation-absorption efficiency and limited surface area hinder their further radiochemotherapeutic applications. To address these issues, we designed Janus-structured gold-mesoporous silica nanoparticles using a modified sol–gel method. This multifunctional theranostic nanoplatform was subsequently modified <i>via</i> the conjugation of folic acid for enhanced HCC targeting and internalization. The loaded anticancer agent doxorubicin can be released from the mesopores in a pH-responsive manner, facilitating selective and safe chemotherapy. Additionally, the combination of chemotherapy and radiotherapy induced synergistic anticancer effects <i>in vitro</i> and exhibited remarkable inhibition of tumor growth <i>in vivo</i> along with significantly reduced systematic toxicity. Additionally, the Janus NPs acted as targeted computed tomography (CT)-imaging agents for HCC diagnosis. Given their better performance in chemoradiotherapy and CT imaging as compared with that of their core–shell counterparts, this new nanoplatform designed with dual functionalities provides a promising strategy for unresectable HCC theranostics