Approaches to neural tissue engineering using scaffolds for drug delivery

Willerth, Stephanie M.; Sakiyama‐Elbert, Shelly E.

doi:10.1016/j.addr.2007.03.014

Cited by 334 publications

(256 citation statements)

References 140 publications

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“…In the USA, 360 000 people suffer from upper extremity paralytic syndromes on an annual basis and approximately 253 000 people in the USA live with the after-effects of spinal cord injury. Moreover, each year this number grows by an estimated 11 000 people in the USA (Willerth and Sakiyama-Elbert, 2007) and in Europe more than 300 000 cases of peripheral nerve injury are reported annually (Ciardelli and Chiono, 2006;Bueno and Shah, 2008).…”

Section: Introductionmentioning

confidence: 99%

Application of conductive polymers, scaffolds and electrical stimulation for nerve tissue engineering

Ghasemi‐Mobarakeh¹,

Prabhakaran²,

Morshed³

et al. 2011

J Tissue Eng Regen Med

603

389

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Among the numerous attempts to integrate tissue engineering concepts into strategies to repair nearly all parts of the body, neuronal repair stands out. This is partially due to the complexity of the nervous anatomical system, its functioning and the inefficiency of conventional repair approaches, which are based on single components of either biomaterials or cells alone. Electrical stimulation has been shown to enhance the nerve regeneration process and this consequently makes the use of electrically conductive polymers very attractive for the construction of scaffolds for nerve tissue engineering. In this review, by taking into consideration the electrical properties of nerve cells and the effect of electrical stimulation on nerve cells, we discuss the most commonly utilized conductive polymers, polypyrrole (PPy) and polyaniline (PANI), along with their design and modifications, thus making them suitable scaffolds for nerve tissue engineering. Other electrospun, composite, conductive scaffolds, such as PANI/gelatin and PPy/poly(ε-caprolactone), with or without electrical stimulation, are also discussed. Different procedures of electrical stimulation which have been used in tissue engineering, with examples on their specific applications in tissue engineering, are also discussed.

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Section: Introductionmentioning

confidence: 99%

Application of conductive polymers, scaffolds and electrical stimulation for nerve tissue engineering

Ghasemi‐Mobarakeh¹,

Prabhakaran²,

Morshed³

et al. 2011

J Tissue Eng Regen Med

603

389

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“…38,42,55,56 In order to make a comprehensive overview of their use in spinal cord injury repair strategies we decided to classify hydrogels on the basis of the following.…”

Section: ' Hydrogelsmentioning

confidence: 99%

Hydrogels in Spinal Cord Injury Repair Strategies

Perale

Rossi

Sundström

et al. 2011

ACS Chem. Neurosci.

144

123

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)Mi.To. Technology s.r.l., Licensing Department, Viale Vittorio Veneto 2/a, 20124 Milan, Italy T raumatic spinal cord injury (SCI) is an irreversible dramatic event that can incapacitate victims for life. 1À4 Although the incidence is relatively low, the often severe disability that follows and the fact that the victims are often young people, the consequences for the patient is severe and the impact on societal costs is significant. The injury is the result of a primary event due to contusive, compressive, or stretch injury, 1,2,5 followed by the so-called "secondary injury", commonly considered the main cause of the post-traumatic neural degeneration of the cord itself. 6À8 Functional deficits of SCI are caused by different temporal events: spinal cord compression and/or contusion lead to ischemic events that limit both oxygen and glucose contribution to the tissue, with concomitant neuronal cell death, axon damage, and demyelination. 5 Subsequently, glial activation, release of inflammatory factors and cytokines, and scar formation that impedes axons to regrow 8,9 aggravate the progression of the damage.SCI research is following two principal paths. 6,9À11 The first one, already applied in human cases, is based on systemic pharmacological treatments in order to contain side effects (ischemia, free radical release, and inflammation) using neuroprotective drugs (such as corticosteroids) 12À14 and to promote self-regeneration using stimulating factors. 15 The second one relies on tissue engineering 16À18 approaches such as the direct injection of stem cells 19À21 and active agents (drugs, antibodies, and peptides) into the affected area with the aim to bridge the lesion, possibly after removal of the glial scar or reducing endogenous neurite-inhibitory molecules. 22,23 Direct injection of in vitro cultured cells or drugs is the most common choice, but keeping transplanted cells in the lesion area is often desired as transplanted cells readily leave the zone of injection if not confined by any support. To achieve this, a new potential approach is to combine material science with tissue engineering as has been proposed and developed. 16,24À26 In Figure 1 are presented classic tissue engineering approaches as the combination of scaffolds with cells and active agents in order to replace damaged parts of biological tissues. 17,18 In the wide field of biomaterials, increased attention is given to polymers, not only to fabricate three-dimensional scaffolds but also to develop injectable systems for tissue engineering. 26À34 One of the most suitable classes of compounds for these purposes is surely represented by hydrogels. 16,28,31,35À39 These polymers are typically soft and elastic due to their thermodynamic compatibility with water. 16,33,36,40 They can be designed as temporary structures having desired geometry and physical, chemical, and mechanical properties adequate for implantation into chosen target tissue. 6,41À43The aim of this Review is to show the different types of hydrogels used as scaffolds for...

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“…One of the first considerations when designing a scaffold for tissue engineering is the choice of material. The three main material types which have been successfully investigated to be applied in developing scaffolds include (i) natural polymers, (ii) synthetic polymers, and (iii) ceramics (Willerth & Sakayama-Elbert, 2007;Radulescu et al, 2007).…”

Section: Decent Materials For Scaffolds Fabricationmentioning

confidence: 99%

“…It can be used for wound dressing, drug delivery, and tissue engineering (cartilage, nerve and liver tissue) applications. These properties include: (Willerth et al, 2007): -Minimal foreign body reaction, -Mild processing conditions (synthetic polymers often need to be dissolved in harsh chemicals; chitosan will dissolve in water based on pH), -Controllable mechanical/biodegradation properties (such as scaffold porosity or polymer length), and -Availability of chemical side groups for attachment to other molecules. Chitosan has already been investigated for adoption in the engineering of cartilage, nerve, and liver tissue.…”

Section: Natural Materialsmentioning

confidence: 99%