Biodegradable pH-responsive hydrogels for controlled dual-drug release

Xu, Liang; Qiu, Linzi; Yang, Sheng; Sun, Yun; Deng, Linhong; Li, Xinqing; Bradley, Mark; Zhang, Rong

doi:10.1039/c7tb01851g

Cited by 96 publications

(54 citation statements)

References 46 publications

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“…These results suggest a key role of IMZ‐Ni 2+ bonds in providing effective energy dissipation pathway to the strecthed hydrogels. These experiments also demonstrate a simple way to tailor the hydrogel mechanical properties and the pH responsive property may be useful for specialized applications …”

Section: Resultsmentioning

confidence: 84%

Dual Cross‐Linked Hydrogels with High Strength, Toughness, and Rapid Self‐Recovery Using Dynamic Metal–Ligand Interactions

Dutta

Das

2019

Macro Materials & Eng

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low density of polymer cross-links. Typical fracture energy of a synthetic hydrogel is about 10 J m −2 , [11] which is orders of magnitude lower than that of cartilage (≈1000 J m −2 ), [12] and natural rubbers (10000 J m −2 ). [13] More often than not, a compromise between high strength and toughness has to be made [14] as they are typically mutually exclusive properties. In recent years, extensive efforts have been directed toward addressing this problem by introducing energy dissipative mechanisms into the gel network. [15] Several strategies have been reported in the literature to design hydrogels with improved mechanical properties. Examples include organic-inorganic nanocomposite hydrogels, [16] slide-ring hydrogels, [17] nonswellable hydrogels, [18] and double network (DN) hydrogels. [19] Among these approaches, the DN strategy combines two polymer networks, one of which contains sacrificial bonds that dissociate during application of stress to provide dissipation of energy, and the other network is flexible and lightly cross-linked, and maintains hydrogel structural integrity during the process of deformation. Unlike chemically cross-linked DN hydrogels which do not exhibit fatigue resistance due to irreversible breakage of the cross-links during loading, [19] utilizing physical cross-links as sacrificial bonds enables gel recovery after a loading cycle. [20] However, in most instances, the hydrogel requires long time and elevated temperature to repair the damage of loading. Henderson et al. designed a triblock amphiphilic copolymer where the polyelectrolyte midblock poly(methacrylic acid) was flanked by glassy end blocks of poly(methyl methacrylate). The midblock was ionically cross-linked using divalent cations to obtain a high strength (1 MPa) hydrogel. [21] However, 12 h of waiting time at room temperature was required for the hydrogel to recover 60% of its dissipated energy. Zheng and coworkers reported a physically cross-linked Agar/Polyacrylamide (PAM) DN hydrogel with tensile strength of 1 MPa, but after first loading even after resting for 4 days at room temperature the mechanical properties of the recovered hydrogel did not improve significantly. [22] Heating the gel at 100 °C was required for the gel to recover back 65% of dissipated energy and 90% of elastic modulus compared to the first loading cycle. When the PAM network was modified by introducing hydrophobic Dual Cross-Linked Hydrogels A dual cross-linking design principle enables access to hydrogels with high strength, toughness, fast self-recovery, and robust fatigue resistant properties. Imidazole (IMZ) containing random poly(acrylamide-co-vinylimidazole) based hydrogels are synthesized in the presence of Ni 2+ ions with low density of chemical cross-linking. The IMZ-Ni 2+ metal-ligand cross-links act as sacrificial motifs to effectively dissipate energy during mechanical loading of the hydrogel. The hydrogel mechanical properties can be tuned by varying the mol% of vinylimidazole (VIMZ) in the copolymer and by changing the VIMZ/ Ni 2+ r...

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Section: Resultsmentioning

confidence: 84%

Dual Cross‐Linked Hydrogels with High Strength, Toughness, and Rapid Self‐Recovery Using Dynamic Metal–Ligand Interactions

Dutta

Das

2019

Macro Materials & Eng

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“…On the other hand, stimuli-responsive nanocarriers have shown the ability to control the release profile of drugs (as a triggered release) using external factors such as ultrasound [ 96 ], heat [ 97 – 99 ], magnetism [ 100 , 101 ], light [ 102 ], pH [ 103 ], and ionic strength [ 104 ], which can improve the targeting and allow greater dosage control (Fig. 2 ).…”

Section: Drug Designing and Drug Delivery Process And Mechanismmentioning

confidence: 99%

Nano based drug delivery systems: recent developments and future prospects

et al. 2018

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Nanomedicine and nano delivery systems are a relatively new but rapidly developing science where materials in the nanoscale range are employed to serve as means of diagnostic tools or to deliver therapeutic agents to specific targeted sites in a controlled manner. Nanotechnology offers multiple benefits in treating chronic human diseases by site-specific, and target-oriented delivery of precise medicines. Recently, there are a number of outstanding applications of the nanomedicine (chemotherapeutic agents, biological agents, immunotherapeutic agents etc.) in the treatment of various diseases. The current review, presents an updated summary of recent advances in the field of nanomedicines and nano based drug delivery systems through comprehensive scrutiny of the discovery and application of nanomaterials in improving both the efficacy of novel and old drugs (e.g., natural products) and selective diagnosis through disease marker molecules. The opportunities and challenges of nanomedicines in drug delivery from synthetic/natural sources to their clinical applications are also discussed. In addition, we have included information regarding the trends and perspectives in nanomedicine area.

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“…Hydrogels that include aptamers can also be used to reversibly catch and release target materials in response to changes in pH or temperature. 157 Moreover, the programmable 3D structure of hydrogels can provide matrices that immobilize nucleic acids without the need to add additional supports; this trait simplifies the structure of the sensor. Use of liquid crystals (LCs) enables direct detection of aptamers' conformation changes.…”

Section: Materials Property-based Aptasensormentioning

confidence: 99%