Temperature and pH-responsive polymeric composite membranes for controlled delivery of proteins and peptides

Zhang, Kai; Wu, Xiao Yu

doi:10.1016/j.biomaterials.2003.12.032

Cited by 158 publications

(85 citation statements)

References 24 publications

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“…There is a wide variety of devices for such controlled delivery to cells, based on, for example, nanostructured materials, [102] hydrogels, [103] biodegradable materials, [104] and membranes. [105] A good delivery device should enable temporal and spatial control, and minimal passive release of active components before triggering.…”

Section: Chemical Stimulationmentioning

confidence: 99%

Electronic Control of Cell Cultures Using Conjugated Polymer Surfaces

Persson¹

2014

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In the field of bioelectronics various electronic materials and devices are used in combination with biological systems in order to create novel applications within cell biology and medicine. A famous example of a successful bioelectronics application is the pacemaker. Metals are the most common electrical conductors, whereas polymers are generally considered being insulators. However, in the late 1970s it was shown that a special class of polymers with conjugated double bonds, could in fact, after some chemical modifications, conduct electricity. This was the start of the research field known as conducting polymers, and then later on organic electronics, a research area that has grown rapidly during the last decades. Conjugated polymers are also suitable to interact and interface with cells and tissues, as they are generally soft, flexible and biocompatible. In addition, their chemical properties can be tailor-made through synthesis to fit biological requirements and functions. During the last years applications using organic bioelectronics have become numerous. This thesis describes applications based on different conjugated polymers aiming to stimulate and control cell cultures. When culturing cells it is of interest to be able to control events such as adhesion, spreading, proliferation, differentiation and detachment. First, the impact of different polymer compositions and redox states on the adhesion of bacteria and subsequent biofilm formation was investigated. Similar polymer electrodes were also used to steer differentiation of neural stem cells, through changes in the surface exposure of a relevant biomolecule. Controlled delivery of molecules was achieved by coating nanoporous membranes with polymers that swell and contract when changing the redox state. Finally, electronic control over cell detachment using a water-soluble polymer was achieved. When applying a positive potential to this polymer, it swells, cracks and finally detaches, taking the cells that was cultured on top along with it. Together, the work and results presented in this thesis demonstrate a versatile conjugated polymer technology to achieve electronic control of the different growth stages of cell cultures as well as cellular functions. POPULÄRVETENSKAPLIG SAMMANFATTNINGOlika plaster finns numera överallt omkring oss och utgör ett av de absolut vanligaste materialen i vår vardag. Även elektronik har blivit en naturlig del av vår tillvaro och finns i en mängd olika produkter. Inom medicinsk teknik kommer allt fler applikationer som innefattar elektronik, ett exempel är pacemakern. Arbetet som ligger till grund för denna avhandling strävar efter att kombinera plaster och elektronik för tillämpningar inom medicin och cellbiologi.Plaster består till största delen av polymerer samt olika tillsatser för att få ett material med önskade egenskaper. Polymerer är i sin tur uppbyggda av långa kedjor av identiska molekylära byggstenar, så kallade monomerer. Monomerens kemi och struktur bestämmer även egenskaperna hos polymeren. Med hjä...

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Section: Chemical Stimulationmentioning

confidence: 99%

Electronic Control of Cell Cultures Using Conjugated Polymer Surfaces

Persson¹

2014

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“…These multi-stimuli-responsive changes can be utilized to create a large variety of smart devices, including sensors, actuators and controlled release systems, for various practical applications [42]. For example, the combination of a thermo-responsive monomer like NIPAM with one of a pH-responsive monomer yields double-responsive co-polymers [43,44]. Multi-stimulus-responsive polymers offer great advantages in drug delivery.…”

Section: Multi-stimulus-responsive Co-polymers Hyperbranched Polymersmentioning

confidence: 99%

Environmental-Sensitive Hyperbranched Polymers as Drug Carriers

Jiang

Xia

2008

Designed Monomers and Polymers

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The present review deals with the design and preparation of environment-sensitive hyperbranched polymers, such as pH-, temperature-sensitive and salt-triggered polymers, in order to be employed as drug-delivery system. In particular, using known and well-characterized basic hyperbranched polymers as starting materials, this review discusses the kind of structural modifications that these polymers were subjected to for preparing nanocarriers of low toxicity, high encapsulating capacity, specificity to certain biological cells and transport ability under different environment conditions. Due to the great number of external groups of hyperbranched polymers either functionalization or multifunctionalization can occur, providing products that fulfill one or more of the requirements that an effective drug carrier should exhibit. Thus, hyperbranched polymers will play a significant role in the future development of new biomedical devices for the treatment of human diseases.  Koninklijke Brill NV, Leiden, 2008

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“…The first term is the Flory-Huggins contribution (2) In this expression, we use a "bare" chi parameter χ o that includes interactions other than those responsible for associative behavior and electrostatic interactions. Terms proportional to the volume fraction of the polymer have been omitted.…”

Section: Model and Phase Equilibrium Conditionsmentioning

confidence: 99%

Control of Gel Swelling and Phase Separation of Weakly Charged Thermoreversible Gels by Salt Addition

Solis

Vernon

2007

Macromolecules

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Doping of thermoreversible polymer gels with charged monomers provides a way to control phase separation and gelation conditions by coupling the properties of the gel with a tunable ionic environment. We analyze the dependence of the gelation and phase separation conditions on the amount of salt present using a mean field model of weakly charged associative polymers. The ions and co-ions present are explicitly considered at the mean field level, and we determine their concentrations in the different equilibrium phases when the system undergoes phase separation. For weak polymer charge, the entropic contributions of the ions to the free energy of the system play a central role in the determination of the location of phase equilibrium. In the simplest case, when the associative interaction responsible for gel formation is independent of the electrostatic interaction, the addition of salt changes the polymer equilibrium concentrations and indirectly changes the measurable swelling of the gel. We construct phase diagrams of these systems showing the location of the coexistence region, the gel-sol boundary and the location of the tie-lines. We determine the swelling of the gel within the co-existence region. Our main result is that the description of the effect of the salt on the properties of the weakly charged gel can be described through an extra contribution to the effective immiscibility parameter χ proportional to the square of the doping degree f 2 and to the inverse square of the added salt concentration s −2 .

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Temperature and pH-responsive polymeric composite membranes for controlled delivery of proteins and peptides

Cited by 158 publications

References 24 publications

Electronic Control of Cell Cultures Using Conjugated Polymer Surfaces

Electronic Control of Cell Cultures Using Conjugated Polymer Surfaces

Environmental-Sensitive Hyperbranched Polymers as Drug Carriers

Control of Gel Swelling and Phase Separation of Weakly Charged Thermoreversible Gels by Salt Addition

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