Patterned Plastics That Change Physical Structure in Response to Applied Chemical Signals

Seo, Wanji; Phillips, Scott T.

doi:10.1021/ja104420k

Cited by 146 publications

(217 citation statements)

References 15 publications

Supporting

Mentioning

215

Contrasting

Unclassified

Order By: Relevance

“…[56,[77][78][79] Note,t his mode of activation can also be triggered by enzymes (see below). [80][81][82][83][84][85][86] In particular,t he allyloxy group has been used to release ah emiacetal that subsequently decomposed into ad ialdehyde. [80][81][82][83][84][85][86] In particular,t he allyloxy group has been used to release ah emiacetal that subsequently decomposed into ad ialdehyde.…”

Section: Activation By Chemical Reagentsmentioning

confidence: 99%

“…Thea llyloxy and allylamino groups have been activated by metal-containing reducing agents,s uch as [Pd( Table 1). [83] Disulfide bridges provide biologically relevant precursors to initiate self-immolation after activation by thiols, [87] such as dithiothreitol [32,88] (entries 3-4, Table 1). [83] Disulfide bridges provide biologically relevant precursors to initiate self-immolation after activation by thiols, [87] such as dithiothreitol [32,88] (entries 3-4, Table 1).…”

Section: Activation By Chemical Reagentsmentioning

confidence: 99%

See 1 more Smart Citation

Self‐Immolative Spacers: Kinetic Aspects, Structure–Property Relationships, and Applications

et al. 2015

View full text Add to dashboard Cite

Self-immolative spacers are covalent assemblies tailored to correlate the cleavage of two chemical bonds after activation of a protective part in a precursor: Upon stimulation, the protective moiety is removed, which generates a cascade of disassembling reactions leading to the temporally sequential release of smaller molecules. Originally introduced to overcome limitations for drug delivery, self-immolative spacers have gained wide interest in medicinal chemistry, analytical chemistry, and material science. For most applications, the kinetics of the disassembly of the activated self-immolative spacer governs functional properties. This Review addresses kinetic aspects of self-immolation. It provides information for selecting a particular self-immolative motif for a specific demand. Moreover, it should help researchers design kinetic experiments and fully exploit the rich perspectives of self-immolative spacers.

show abstract

Section: Activation By Chemical Reagentsmentioning

confidence: 99%

Section: Activation By Chemical Reagentsmentioning

confidence: 99%

Self‐Immolative Spacers: Kinetic Aspects, Structure–Property Relationships, and Applications

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Moreover, the fabrication technique is exceptionally mild and thus enables the formation of core−shell microcapsules using sensitive depolymerizable polymers such as poly(phthalaldehyde) (PPHA) (Figure 1). 16,17 Herein we demonstrate these concepts by fabricating model stimuli-responsive core−shell microcapsules using PPHA that contains a fluoride-responsive endcap. The end-cap controls the stability and reactivity of the PPHA polymer and thus enables release of the contents of the capsules selectively when exposed to fluoride (a model stimulus), even in aqueous media.…”

Section: ■ Introductionmentioning

confidence: 96%

Stimuli-Responsive Core–Shell Microcapsules with Tunable Rates of Release by Using a Depolymerizable Poly(phthalaldehyde) Membrane

et al. 2013

Self Cite

View full text Add to dashboard Cite

Flow-focusing microfluidic techniques were used to provide access to core−shell microcapsules in which the shell is composed of end-capped poly(phthalaldehydes) that depolymerize completely from head-to-tail in response to fluoride. Microcapsules made from these depolymerizable polymers provide an amplified response to the applied chemical signal, where the rate of the response can be tuned both by varying the length of the polymer and the thickness of the shell wall. ■ INTRODUCTIONStimuli-responsive polymeric core−shell microcapsules are promising materials for controlled release applications. 1−8 Capsules of this type typically release their contents either through induced chemical changes in the polymers that compose the shell or via bulk structural changes to the shell wall. 1 These traditional triggered-release strategies provide responses that are nonamplified: i.e., a single membrane−signal interaction produces one small structural change in the shell wall, whereas release occurs only after many signals have reacted with and altered the shell wall. In contrast, a new release strategy has emerged where shell walls are formed from polymers that depolymerize continuously and completely from head-to-tail when an appropriate signal is detected by the polymer. 1,9 This depolymerization reaction provides an amplified response that, in theory, increases the sensitivity of the capsules as well as their rate of response once the appropriate signal is detected. Despite these favorable attributes, however, only one example of a stimuli-responsive core−shell polymeric microcapsule made from a head-to-tail depolymerizable polymer has been demonstrated to date, 10 with additional related examples demonstrated in responsive nanocapsules and micelles. 11,12 Further development of this depolymerizable shell wall concept has been hindered by the limited number of polymers that are capable of depolymerizing from head-to-tail in response to a specific signal, as well as by substantial challenges in fabricating core−shell microcapsules using polymers that are primed to depolymerize.In this article, we describe the use of flow-focusing microfluidic strategies for fabricating these types of depolymerizable core−shell microcapsules. 13−15 This technique is highly reproducible, readily forms capsules that contain aqueous interiors, is capable of generating capsules that can be suspended in an aqueous solution that differs from the solution within the capsule, and does not require synthetic manipulation of the polymer for incorporation into the shell wall. Moreover, the fabrication technique is exceptionally mild and thus enables the formation of core−shell microcapsules using sensitive depolymerizable polymers such as poly(phthalaldehyde) (PPHA) (Figure 1). 16,17 Herein we demonstrate these concepts by fabricating model stimuli-responsive core−shell microcapsules using PPHA that contains a fluoride-responsive endcap. The end-cap controls the stability and reactivity of the PPHA polymer and thus enables release of the ...

show abstract

“…1 Most reported depolymerization mechanisms of polymers or selfimmolative degradation of dendrimers involve a cascade of self-elimination reactions 2–4 or hemiacetal hydrolysis 5 . However, a few degrade through such processes combined with a cyclization mechanism involving a diamine spacer and yielding urea derivatives.…”

mentioning

confidence: 99%

Intramolecular Cyclization for Stimuli-Controlled Depolymerization of Polycaprolactone Particles Leading to Disassembly and Payload Release

Lux

Almutairi

2013

ACS Macro Lett.

View full text Add to dashboard Cite

Developing polymer chemistries capable of on-demand, controlled depolymerization is an important tool in a broad variety of applications in science, technology, and industry. We report functionalized poly(caprolactone)s (PCL)s designed to allow on-demand and complete depolymerization through incorporation of pendant protected amino groups that, on deprotection, trigger nucleophilic attack and yield a single cyclic product. Two cleavable protecting groups were used to cap PCL: light sensititve o-nitrobenzyl alcohol (ONB) and tert-butyl carbamate (Boc) (for proof of concept). NMR confirmed that PCL-Boc degrades completely into the designed intramolecular cyclization products within a day upon deprotection. TEM visualization of particles made from PCL-ONB encapsulating iron oxide nanoparticles reveals complete disruption of nanoparticles and release of payload. This work demonstrates that intramolecular cyclization within the polymer backbone is an excellent route to accelerate polymer degradation by backbiting reactions into small fragments that should be easily cleared from the circulation.

show abstract

Patterned Plastics That Change Physical Structure in Response to Applied Chemical Signals

Cited by 146 publications

References 15 publications

Self‐Immolative Spacers: Kinetic Aspects, Structure–Property Relationships, and Applications

Self‐Immolative Spacers: Kinetic Aspects, Structure–Property Relationships, and Applications

Stimuli-Responsive Core–Shell Microcapsules with Tunable Rates of Release by Using a Depolymerizable Poly(phthalaldehyde) Membrane

Intramolecular Cyclization for Stimuli-Controlled Depolymerization of Polycaprolactone Particles Leading to Disassembly and Payload Release

Contact Info

Product

Resources

About