Multi-Responsive Hydrogels Functionalized with a Photochromic Spiropyran-Conjugated Chitosan Network

Vales, Temmy Pegarro; Badon, Isabel Wen; Kim, Ho‐Joong

doi:10.1007/s13233-018-6126-9

Cited by 22 publications

(10 citation statements)

References 20 publications

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“…Photo isomerization processes are the structural change of photoex cited molecules in between different isomers, such as cis-trans or constitutional isomers. [71,72] Their photochromic properties can be benefi cial in terms of easy indication and monitoring of the photo chemical reaction or for manufacturing sunglasslike hydrogel contact lenses. Azobenzene is a wellknown example that undergoes photoinitiated (365 nm) transforma tion from transconfiguration to cisconfiguration via a π-π* transition and can relax back to the more stable transisomer by visible light irradiation (445 nm) or heating.…”

Section: Molecular Mechanismsmentioning

confidence: 99%

“…Mater. 2019, 31,1807333 Isomerization Azobenzene [21,22,25,26,28,[64][65][66][67]106,108,109,[137][138][139] Spiropyran [67,69,72,73,75,105,[119][120][121][122]130] maleimides, [50,51] stilbene, [52,53] and [4+4]cycloaddition of anthracenes. [54][55][56] Many cycloaddition reactions can be acti vated with UV light.…”

Section: Molecular Mechanismsmentioning

confidence: 99%

“…[70] The change from one isomer to the other is accompanied by a change in color, therefore pyranebased hydrogels possess inherent photochromic properties, which were lately shown to be tunable. [71,72] Their photochromic properties can be benefi cial in terms of easy indication and monitoring of the photo chemical reaction or for manufacturing sunglasslike hydrogel contact lenses. [73] As the changes in hydrophilicity upon spi ropyrane isomerization affect the ability of hydrogels to swell, the ring opening or closing of spiropyranes can be used to reversibly toughen or change the volume of hydrogels.…”

Section: Molecular Mechanismsmentioning

confidence: 99%

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Design and Applications of Photoresponsive Hydrogels

2019

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materials with diverse applications in var ious fields due to their tunable chemistry structure and physical properties as well as excellent biocompatibility. [2][3][4][5] Hydrogel research has evolved from static mate rials to smart ones, whose structures and property show responsiveness to external stimuli, including temperature, pH, light, electric or magnetic fields, and the pres ence of enzymes or ion concentrations. [6][7][8][9][10][11] This unprecedented level of control over material properties has driven both med ical and industrial fields into the realm of possibility: controlled drug delivery, [12] chemical sensors, [13] soft actuators or robotics, [14][15][16] or scaffolds for dynamic 3D cell culture. [17] Photoresponsiveness is attractive due to the inherent advan tages of light as stimulus. Light is non invasive and allows remote manipulation of materials without requiring additional reagents, thus, with limited byproducts. Modulation of irradiation parameters, such as light intensity and irradiation time, permits the pre cise control of irradiation dosage, thereby, the degree of photo reactions. Spatial control can be achieved in both 2D and 3D, and temporal control is possible by simply turning the respec tive light source on or off. Wavelengthselective photo chemical reactions can be used for orthogonal photomediation of hydrogel properties. [18] Photoresponsive hydrogels, as externally tunable materials, strongly contribute to the field of soft smart materials in regard to the abovementioned applications. [19] In this review, we elaborate on the design and the emerging appli cations of photoresponsive hydrogels. A comprehensive review about utilizing light for the formation of hydrogels is given by Mi and coworkers. [20] First, we discuss responsive modes and photochemical mechanisms of photoresponsive hydrogels. Fol lowing this, we highlight their applications for dynamic cell environments, smart biointerfaces, controlled drug delivery, photodriven actuators, and lighthealing materials. The review concludes with an outlook on the challenges and potential future approaches for photo responsive hydrogels. Light as Stimulus for Hydrogels Macroscopic Hydrogel PhotoresponsesThe interaction of light with photoresponsive hydrogels can result in different responses, some of which are observable with the bare eye. Those include hydrogel formation or degradation, network contraction or expansion, and chemical modifications in the network, which then have an immediate consequence on Hydrogels are the most relevant biochemical scaffold due to their tunable properties, inherent biocompatibility, and similarity with tissue and cell environments. Over the past decade, hydrogels have developed from static materials to "smart" responsive materials adapting to various stimuli, such as pH, temperature, chemical, electrical, or light. Light stimulation is particularly interesting for many applications because of the capability of contact-free remote manipulation of biomaterial properties and inherent spatial and t...

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Section: Molecular Mechanismsmentioning

confidence: 99%

Section: Molecular Mechanismsmentioning

confidence: 99%

Section: Molecular Mechanismsmentioning

confidence: 99%

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Design and Applications of Photoresponsive Hydrogels

2019

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“…Furthermore, it was subjected to surface functionalization using spiropyran with -COOH functionality to establish amide linkage with chitosan interpenetrated networks. The optical responses arouse due to the ring opened merocyanine state (upon UV exposure) and protonated merocyanine state (on acidic conditions) [87]. Commercial PU fibers were polymerized in situ to produce compact polypyrrole layers with good conformability to be employed to sense chloroform vapors.…”

Section: Surface Functionalization and Grafting Based Sensory Nanofibersmentioning

confidence: 99%

Conjugated Copolymers through Electrospinning Synthetic Strategies and Their Versatile Applications in Sensing Environmental Toxicants, pH, Temperature, and Humidity

et al. 2020

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Conjugated copolymers (CCPs) are a class of polymers with excellent optical luminescent and electrical conducting properties because of their extensive π conjugation. CCPs have several advantages such as facile synthesis, structural tailorability, processability, and ease of device fabrication by compatible solvents. Electrospinning (ES) is a versatile technique that produces continuous high throughput nanofibers or microfibers and its appropriate synchronization with CCPs can aid in harvesting an ideal sensory nanofiber. The ES-based nanofibrous membrane enables sensors to accomplish ultrahigh sensitivity and response time with the aid of a greater surface-to-volume ratio. This review covers the crucial aspects of designing highly responsive optical sensors that includes synthetic strategies, sensor fabrication, mechanistic aspects, sensing modes, and recent sensing trends in monitoring environmental toxicants, pH, temperature, and humidity. In particular, considerable attention is being paid on classifying the ES-based optical sensor fabrication to overcome remaining challenges such as sensitivity, selectivity, dye leaching, instability, and reversibility.

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“…[61] They may be linked to polymers by utilizing them as initiators or quenchers, or by coupling them to functional groups on the polymer chain. [28,61,62] Our approach to make spiropyran end-functionalized homopolymers is to first synthesize a macro-indolenium salt and then treat it with a suitable o-hydroxy benzaldehyde. This allows to synthesize and characterize polymers without the notoriously tedious purification of small molecule spiropyrans.…”

Section: Synthesis Of Spiropyran Functionalized Homopolymersmentioning

confidence: 99%

Light-responsive block copolymers with a spiropyran located at the block junction

Apebende

Dubois

Bruns

2019

European Polymer Journal

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Block copolymers with a functional group between their blocks are relative little explored, even though this molecular architecture can reduce the aggregation of the functional groups, promote the phase separation in nanophase-separated materials, and have other interesting effects. Spiropyrans are wellknown for their ability to switch to their polar merocyanine form in response to light, force and other stimuli. The synthesis of stimuli-responsive AB-type block copolymers with spiropyran moieties located at the junction of the blocks is presented here. A homopolymer is synthesized from an indole-based atom transfer radical polymerization (ATRP) initiator, followed by its modification to a spiropyran endfunctionalized polymer. The spiropyran functionalized polymer is then used as a macro-initiator for the synthesis of a second polymer block by ring opening polymerization (ROP). Alternatively, spiropyran homopolymers are conjugated to other preformed polymers by esterification. The resulting block copolymers reversibly switch under UV and white light irradiation over multiple cycles, and a block copolymer reduced the tendency of the merocyanine to aggregate during switching. The stimuliresponsive block copolymer could be useful for a range of applications, e.g. for bioinspired polymersome nanoreactors, or in membranes with switchable permeability.

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Multi-Responsive Hydrogels Functionalized with a Photochromic Spiropyran-Conjugated Chitosan Network

Cited by 22 publications

References 20 publications

Design and Applications of Photoresponsive Hydrogels

Design and Applications of Photoresponsive Hydrogels

Conjugated Copolymers through Electrospinning Synthetic Strategies and Their Versatile Applications in Sensing Environmental Toxicants, pH, Temperature, and Humidity

Light-responsive block copolymers with a spiropyran located at the block junction

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