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1.
    
Under a rational design, combining multiple constituents into a single nano‐object will not only bridge the unique properties of individual materials to leverage research both fundamentally and practically, but will also improve conventional sensing, imaging, and therapeutic efficacies. Such a nano‐object (<100 nm) can be constructed by covalently bonding ZnO quantum dots (QDs) to nonlinear poly(ethylene glycol)‐based nanogel network chains, followed by appropriate growth of metallic Au. With the polymer gel network serving as a three‐dimensional scaffold, the fluorescence of ZnO QDs can be well protected, while metal Au still retains its surface plasmon resonance property. The ZnO QDs covalently bonded to the thermo‐responsive gel network chains can sensitively respond to temperature change of the surrounding fluids over the physiologically important range of 37–42 °C, converting the disruptions in homeostasis of local temperature into stable, robust and high‐resolution fluorescent signals. The thermoresponsive hybrid nanogels can not only enter into and light up B16F10 cells, but also regulate the release of a model anticancer drug, temozolomide, in response to either local environmental temperature change or external near‐infrared light‐induced localized hyperthermia from metal Au. The combined chemo‐photothermal therapy can significantly improve the therapeutic efficacy due to a synergistic effect.  相似文献   

2.
    
Despite their potential in various fields of bioapplications, such as drug/cell delivery, tissue engineering, and regenerative medicine, hydrogels have often suffered from their weak mechanical properties, which are attributed to their single network of polymers. Here, supertough composite hydrogels are proposed consisting of alginate/polyacrylamide double‐network hydrogels embedded with mesoporous silica particles (SBA‐15). The supertoughness is derived from efficient energy dissipation through the multiple bondings, such as ionic crosslinking of alginate, covalent crosslinking of polyacrylamide, and van der Waals interactions and hydrogen bondings between SBA‐15 and the polymers. The superior mechanical properties of these hybrid hydrogels make it possible to maintain the hydrogel structure for a long period of time in a physiological solution. Based on their high mechanical stability, these hybrid hydrogels are demonstrated to exhibit on‐demand drug release, which is controlled by an external mechanical stimulation (both in vitro and in vivo). Moreover, different types of drugs can be separately loaded into the hydrogel network and mesopores of SBA‐15 and can be released with different speeds, suggesting that these hydrogels can also be used for multiple drug release.  相似文献   

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4.
    
A series of hydrogels with continuously regulatable release behavior can be achieved by incorporating hydrogen bonding and π–π stacking co‐switches in polymers. A poly(nitrophenyl methacrylate‐co‐methacrylic acid) hydrogel (NPMAAHG) for control over drug release is fabricated by copolymerizing 4‐nitrophenyl methacrylate and methacrylic acid using ethylene glycol dimethacrylate as a crosslinker. The carboxylic acid groups and nitrylphenyl groups form hydrogen bonds and π–π stacking interactions, respectively, which act as switches to control the release of guest molecules from the polymers. As revealed by the simulated gastrointestinal tract drug release experiments, the as‐synthesized NPMAAHG hydrogels can be regulated to release only 4.7% of drugs after 3 h in a simulated stomach and nearly 92.6% within 43 h in the whole digestive tract. The relation between the release kinetics and structures and the mechanism of the smart release control are analyzed in terms of diffusion exponent, swelling interface number, drug diffusion coefficient, and velocity of the swelling interface in detail. The results reveal that the release of guest molecules from the hydrogels can be continuously regulated for systemic administration by controlling the ratio of the hydrophilic hydrogen bonds and the hydrophobic π–π stacking switches.  相似文献   

5.
    
This work designs a class of biocompatible PEG‐chitosan@CDs hybrid nanogels by integrating nonlinear poly(ethylene glycol) (PEG), chitosan, and graphitic carbon dots (CDs) into a single nanoparticle for two‐photon fluorescence (TPF) bioimaging, pH and near‐infrared (NIR) light dual‐responsive drug release, and synergistic therapy. Such hybrid nanogels can be simply prepared from a one‐pot surfactant‐free precipitation polymerization of the PEG macromonomers complexed with chitosan and CDs in water, resulting in a semi‐interpenetration of chitosan chains and an immobilization of CDs in the nonlinear PEG networks. The embedded CDs in hybrid nanogels not only serve as an excellent confocal and TPF imaging contrast agent and fluorescent pH‐sensing probe, but also enhance the loading capacity of the hybrid nanogels for hydrophobic anticancer drug. The chitosan can induce a pH‐sensitive swelling/deswelling of the hybrid nanogels for pH‐regulated drug release over the physiologically important range of 5.0–7.4 and surface modulation of embedded CDs to realize fluorescent pH sensing. The thermosensitive nonlinear PEG network can promote the drug release through the local heat produced by the embedded CDs under NIR irradiation. The in vitro results indicate that the hybrid nanogels demonstrated high therapeutic efficacy through the synergistic effect of combined chemo–photothermal treatments.  相似文献   

6.
    
A programmed drug‐delivery system that can transport different anticancer therapeutics to their distinct targets holds vast promise for cancer treatment. Herein, a core–shell‐based “nanodepot” consisting of a liposomal core and a crosslinked‐gel shell (designated Gelipo) is developed for the sequential and site‐specific delivery (SSSD) of tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) and doxorubicin (Dox). As a small‐molecule drug intercalating the nuclear DNA, Dox is loaded in the aqueous core of the liposome, while TRAIL, acting on the death receptor (DR) on the plasma membrane, is encapsulated in the outer shell made of crosslinked hyaluronic acid (HA). The degradation of the HA shell by HAase that is concentrated in the tumor environment results in the rapid extracellular release of TRAIL and subsequent internalization of the liposomes. The parallel activity of TRAIL and Dox show synergistic anticancer efficacy. The half‐maximal inhibitory concentration (IC50) of TRAIL and Dox co‐loaded Gelipo (TRAIL/Dox‐Gelipo) toward human breast cancer (MDA‐MB‐231) cells is 83 ng mL–1 (Dox concentration), which presents a 5.9‐fold increase in the cytotoxicity compared to 569 ng mL–1 of Dox‐loaded Gelipo (Dox‐Gelipo). Moreover, with the programmed choreography, Gelipo significantly improves the inhibition of the tumor growth in the MDA‐MB‐231 xenograft tumor animal model.  相似文献   

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In this work, enzyme‐prodrug therapy (EPT) is engineered into hydrogel biomaterials to achieve localized synthesis of the drugs and their delivery to the adhering cells. The use of EPT in the context of drug delivery mediated by biomaterials significantly empowers the latter in that the same hydrogel is used to successfully synthesize several drugs with dissimilar structures and therapeutic effects. The concentration of the synthesized drugs is conveniently controlled by the concentration of the administered prodrugs. Using prodrugs for two therapeutic agents allows their synthesis and delivery with independent control over the concentration and the time of administration of each of the drugs. Using these tools, sequential delivery of drugs for anti‐inflammatory and anti‐proliferative activity is accomplished whereby the synthesis of drugs is mediated by the same enzyme‐functionalized hydrogel. The use of EPT to perform combination therapy mediated by an implantable biomaterial is also reported. Taken together, these results contribute significantly to the development of flexible and highly powerful tools of substrate‐mediated drug delivery with applications in the design of therapeutic implants and tissue engineering.  相似文献   

9.
    
Hydrogels, a class of materials with a 3D network structure, are widely used in various fields especially in biomedicine. Injectable hydrogels could facilitate the encapsulation and controlled release of small molecular drugs, macromolecular therapeutics, and even cells. With the rapid development of cancer immunotherapy, such injectable hydrogels have attracted wide attention for local immunomodulation to boost systemic anticancer immune responses, realizing more effective immunotherapy at lower doses. The latest progresses in the development of various smart injectable hydrogels for cancer immunotherapy are summarized here. Although applied locally, such injectable hydrogels can activate systemic antitumor immune responses, safely and effectively inhibiting the tumor metastasis and recurrence. Moreover, it is discussed how injectable hydrogel‐based cancer immunotherapy would contribute to the development of next generation of cancer treatment together with their potential for clinical translation.  相似文献   

10.
    
The leading living bacteria formulations currently available are from a limited list of genera and are generally limited to gastrointestinal tract syndromes. A formulation composed of living Bacillus subtilis incorporated in a thermoresponsive hydrogel that hardens after administration on the skin and continuously produces antifungal agents is described. The ability of the formula to support bacteria growth and its mechanical properties and penetrability through the skin are fine‐tuned by varying the ratio between polymer concentrations and bacterial media. The formula penetrates via the stratum corneum and accumulates in the epidermis without penetrating the inner, dermis layer. In vivo results mirror the results seen in vitro: bacillus formulations completely inhibit candida growth, demonstrating clinical effects comparable to those achieved by ketoconazole. LC‐MS/MS analysis of the bacterial formulation confirms the presence of surfactin, the most powerful biosurfactant that possesses a broad antifungal activity. This platform may enable rational design of novel formulations composed of secreting bacteria inside a responsive, smart, hydrogel—which is the prerequisite for producing a successful drug delivery system.  相似文献   

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12.
    
Standard care for early stage breast cancer includes tumor resection and local radiotherapy to achieve long‐term remission. Systemic chemotherapy provides only low locoregional control of the disease; to address this, self‐assembling silk hydrogels that can retain and then deliver doxorubicin locally are described. Self‐assembling silk hydrogels show no swelling, are readily loaded with doxorubicin under aqueous conditions, and release drug over 4 weeks in amounts that can be fine‐tuned by varying the silk content. Following successful in vitro studies, locally injected silk hydrogels loaded with doxorubicin show excellent antitumor response in mice, outperforming the equivalent amount of doxorubicin delivered intravenously. In addition to reducing primary tumor growth, doxorubicin‐loaded silk hydrogels reduce metastatic spread and are well tolerated in vivo. Thus, silk hydrogels are well suited for the local delivery of chemotherapy and provide a promising approach to improve locoregional control of breast cancer.  相似文献   

13.
    
Eye drops are the most common and inexpensive approach to topical ocular drug delivery. Eye drops offer a noninvasive treatment strategy; however, this can be detrimental to therapeutic efficacy when compared to invasive methods such as surgeries, implants, and injections. Improvements to the efficacy of the topical delivery of drugs to ocular tissues are currently being explored and much of this work centers on adjusting the formulation of the eye drops and prolonging the bioavailability of the therapeutic agent. This is often in preference to improving other patient‐focused or clinical factors. In this progress report, conventional, commercially available polymer eye drops are explored and the ability for current and future innovations to maintain the existing benefits of eye drops to the patient is assessed. The final materials and form of the drops (liquid, gel, or other) and the immunological implications for the user are explored. There is currently no consensus for how to most effectively improve the ocular retention and drug delivery capabilities of eye drops, but key issues are highlighted in the context of current methods under development, and potential questions and considerations for future innovations are raised.  相似文献   

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15.
    
This paper reports on the degradation and protein release behavior of a self‐assembled hydrogel system composed of β‐cyclodextrin‐ (βCD) and cholesterol‐derivatized 8‐arm star‐shaped poly(ethylene glycol) (PEG8). By mixing βCD‐ and cholesterol‐derivatized PEG8 (molecular weights 10, 20 and 40 kDa) in aqueous solution, hydrogels with different rheological properties are formed. It is shown that hydrogel degradation is mainly the result of surface erosion, which depends on the network swelling stresses and initial crosslink density of the gels. This degradation mechanism, which is hardly observed for other water‐absorbing polymer networks, leads to a quantitative and nearly zero‐order release of entrapped proteins. This system therefore offers great potential for protein delivery.  相似文献   

16.
    
Unique microneedle arrays prepared from crosslinked polymers, which contain no drug themselves, are described. They rapidly take up skin interstitial fluid upon skin insertion to form continuous, unblockable, hydrogel conduits from attached patch‐type drug reservoirs to the dermal microcirculation. Importantly, such microneedles, which can be fabricated in a wide range of patch sizes and microneedle geometries, can be easily sterilized, resist hole closure while in place, and are removed completely intact from the skin. Delivery of macromolecules is no longer limited to what can be loaded into the microneedles themselves and transdermal drug delivery is now controlled by the crosslink density of the hydrogel system rather than the stratum corneum, while electrically modulated delivery is also a unique feature. This technology has the potential to overcome the limitations of conventional microneedle designs and greatly increase the range of the type of drug that is deliverable transdermally, with ensuing benefits for industry, healthcare providers and, ultimately, patients.  相似文献   

17.
    
The exciting development of hydrogels makes it a promising candidate to be applied in various fields. However, it remains a great challenge to store the precursors of hydrogels and to process them after gelation, like synthetic polymer materials. Herein, spidroin-inspired novel nanogels with extraordinary processability, which can be spun into fibers via direct drawing and fabricated into thermal actuators easily after gelation are prepared. These soluble and spinnable nanogels are composed of a liquid metal core and a poly (acrylic acid) (PAA) shell and are entangled with each other. The as fabricated nanogels and diluted dope solution can be stored >1 month. The as-spun nanogel fibers with hierarchical structures achiev extraordinary mechanical properties (tensile stress of 575 MPa, toughness of 381 MJ m−3) and supercontraction at 60% RH. Besides, a photothermal actuator is prepared by coating the nanogels on a polyethylene substrate with a commercial shading ink, and the as-prepared actuator shows a rapid response to near-infrared light as well as a fast recovery. Molecular dynamics simulation reveals a possible working mechanism of the actuator. This study provides a new strategy to prepare processable nanogels with broad application prospects for smart textiles and soft robots.  相似文献   

18.
    
The successful therapeutic application of small interfering RNA (siRNA) largely relies on the development of safe and effective delivery systems that are able to guide the siRNA therapeutics to the cytoplasm of the target cell. In this report, biodegradable cationic dextran nanogels are engineered by inverse emulsion photopolymerization and their potential as siRNA carriers is evaluated. The nanogels are able to entrap siRNA with a high loading capacity, based on electrostatic interaction. Confocal microscopy and flow cytometry analysis reveal that large amounts of siRNA‐loaded nanogels can be internalized by HuH‐7 human hepatoma cells without significant cytotoxicity. Following their cellular uptake, it is found that the nanogels are mainly trafficked towards the endolysosomes. The influence of two different strategies to enhance endosomal escape on the extent of gene silencing is investigated. It is found that both the application of photochemical internalization (PCI) and the use of an influenza‐derived fusogenic peptide (diINF‐7) can significantly improve the silencing efficiency of siRNA‐loaded nanogels. Furthermore, it is shown that an efficient gene silencing requires the degradation of the nanogels. As the degradation kinetics of the nanogels can easily be tailored, these particles show potential for intracellular controlled release of short interfering RNA.  相似文献   

19.
    
Photothermal therapy (PTT) combined with chemotherapy, a promising strategy for breast cancer treatment, has a high potential to control drug release, reduce multidrug resistance, and improve therapeutic efficacy. The challenge is how to realize tumor ablation in deeper tissue and NIR-controlled drug delivery. Herein, tumor acidity and near-infrared light (NIR) responsive folic acid (FA) functionalized polydopamine (DPA) nanoparticles (NPs) are developed for doxorubicin (DOX) and epigallocatechin-3-gallate (EGCG) dual delivery. With the assistance of NIR, the cellular uptake of DOX-EGCG/DPA-FA NPs is about three- to sixfold higher when compared with the free DOX group and the control group without NIR irradiation. Moreover, biodistribution study in vivo indicates that DPA-FA NPs can enhance tumoral accumulation, penetration, retention of drugs, and display a ≈ 4- and 19-fold higher intra-tumoral distribution than that of the DPA NPs and free drug groups at 24 h postinjection. Furthermore, 60% of breast cancer-bearing mice survive over 70 days in the DOX-EGCG/DPA-FA NPs group. Additionally, DOX-EGCG/DPA-FA NPs can effectively boost therapeutic efficacy by inducing significant suppression of tumor growth and angiogenesis, and enhancement of apoptosis and necrosis of breast cancer cells. Taken together, DOX-EGCG/DPA-FA NPs may have potential applications as a useful nanoscale vector for enhanced cancer therapy.  相似文献   

20.
    
Single wall carbon nanotube (SWNT) based thermo‐sensitive hydrogel (SWNT‐GEL) is reported, which provides an injectable drug delivery system as well as a medium for photothermal transduction. SWNT‐hydrogel alone appears to be nontoxic on gastric cancer cells (BGC‐823 cell line) but leads to cell death with NIR radiation through a hyperthermia proapoptosis mechanism. By incorporating hyperthermia therapy and controlled in situ doxorubicin (DOX) release, DOX‐loaded SWNT‐hydrogel with NIR radiation proves higher tumor suppression rate on mice xenograft gastric tumor models compared to free DOX without detectable organ toxicity. The developed system demonstrates improved efficacy of chemotherapeutic drugs which overcomes systemic adverse reactions and presents immense potential for gastric cancer treatment.  相似文献   

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