51
|
Venkatesh S, Wower J, Byrne ME. Nucleic acid therapeutic carriers with on-demand triggered release. Bioconjug Chem 2009; 20:1773-82. [PMID: 19670897 DOI: 10.1021/bc900187b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biohybrid platforms such as synthetic polymer networks engineered from artificial and natural materials hold immense potential as drug and gene delivery vehicles. Here, we report the synthesis and characterization of novel polymer networks that release oligonucleotide sequences via enzymatic and physical triggers. Chemical monomers and acrylated oligonucleotides were copolymerized into networks, and phosphoimaging revealed that 70% of the oligonucleotides were incorporated into the networks. We observed that the immobilized oligonucleotides were readily cleaved when the networks were incubated with the type II restriction enzyme BamHI. The diffusion of the cleaved fragments through the macromolecular chains resulted in relatively constant release profiles very close to zero-order. To our knowledge, this is the first study which harnesses the sequence-specificity of restriction endonucleases as triggering agents for the cleavage and release of oligonucleotide sequences from a synthetic polymer network. The polymer networks exhibited an oligonucleotide diffusion coefficient of 5.6 x 10(-8) cm(2)/s and a diffusional exponent of 0.92. Sigmoidal temperature responsive characteristics of the networks matched the theoretical melting temperature of the oligonucleotides and indicated a cooperative melting transition of the oligonucleotides. The networks were also triggered to release a RNA-cleaving deoxyribozyme, which degraded a HIV-1 mRNA transcript in vitro. To tailor release profiles of the oligonucleotides, we controlled the structure of the macromolecular architecture of the networks by varying their cross-linking content. When incubated with DNase I, networks of cross-linking content 0.15%, 0.22%, and 0.45% exhibited oligonucleotide diffusion coefficients of 1.67 x 10(-8), 7.65 x 10(-9), and 2.7 x 10(-9) cm(2)/s, and diffusional exponents of 0.55, 0.8, and 0.8, respectively. The modular nature of our platform promises to open new avenues for the creation and optimization of a rich toolbox of novel drug and gene delivery platforms. We anticipate further inquiry into nucleic acid based programmable on-demand switches and modulatory devices of exquisite sensitivity and control.
Collapse
Affiliation(s)
- Siddarth Venkatesh
- Biomimetic and Biohybrid Materials, Biomedical Devices, and Drug Delivery Laboratories, Department of Chemical Engineering, Auburn University, Auburn, Alabama 36849, USA
| | | | | |
Collapse
|
52
|
Winter JO, Han N, Jensen R, Cogan SF, Rizzo JF. Adhesion molecules promote chronic neural interfaces following neurotrophin withdrawal. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2009:7151-4. [PMID: 19965267 DOI: 10.1109/iembs.2009.5335356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neural prostheses and recording devices have been successfully interfaced with the nervous system; however, substantial integration issues exist at the biomaterial-tissue interface. In particular, the loss of neurons at the implantation site and the formation of a gliotic scar capsule diminish device performance. We have investigated the potential of a tissue-engineered coating, consisting of adhesion molecule-modified surfaces (i.e., polylysine and collagen) in combination with neurotrophin application (i.e., brain derived neurotrophic factor, BDNF), to enhance the electrode-host interface. Neurite length and density were examined in a retinal explant model. In the presence of BDNF for 7 days, we found no synergistic effect of BDNF and adhesion molecule-modified surfaces on neurite length, although there was a possible increase in neurite density for collagen-coated surfaces. After BDNF withdrawal (7 days BDNF+/7 days BDNF- medium), we found that both polylysine and collagen treated surfaces displayed increases in neurite length and density over negative, untreated control surfaces. These results suggest that adhesion molecules may be used to support chronic neuron-electrode interfaces induced by neurotrophin exposure.
Collapse
Affiliation(s)
- Jessica O Winter
- William G. Lowrie Department of Chemical Engineering, the Ohio State University, Columbus, OH 43210, USA.
| | | | | | | | | |
Collapse
|
53
|
Madigan NN, McMahon S, O'Brien T, Yaszemski MJ, Windebank AJ. Current tissue engineering and novel therapeutic approaches to axonal regeneration following spinal cord injury using polymer scaffolds. Respir Physiol Neurobiol 2009; 169:183-99. [PMID: 19737633 DOI: 10.1016/j.resp.2009.08.015] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 08/25/2009] [Accepted: 08/29/2009] [Indexed: 12/19/2022]
Abstract
This review highlights current tissue engineering and novel therapeutic approaches to axonal regeneration following spinal cord injury. The concept of developing 3-dimensional polymer scaffolds for placement into a spinal cord transection model has recently been more extensively explored as a solution for restoring neurologic function after injury. Given the patient morbidity associated with respiratory compromise, the discrete tracts in the spinal cord conveying innervation for breathing represent an important and achievable therapeutic target. The aim is to derive new neuronal tissue from the surrounding, healthy cord that will be guided by the polymer implant through the injured area to make functional reconnections. A variety of naturally derived and synthetic biomaterial polymers have been developed for placement in the injured spinal cord. Axonal growth is supported by inherent properties of the selected polymer, the architecture of the scaffold, permissive microstructures such as pores, grooves or polymer fibres, and surface modifications to provide improved adherence and growth directionality. Structural support of axonal regeneration is combined with integrated polymeric and cellular delivery systems for therapeutic drugs and for neurotrophic molecules to regionalize growth of specific nerve populations.
Collapse
|
54
|
Ellis-Behnke RG, Liang YX, Guo J, Tay DKC, Schneider GE, Teather LA, Wu W, So KF. Forever Young: How to Control the Elongation, Differentiation, and Proliferation of Cells Using Nanotechnology. Cell Transplant 2009; 18:1047-58. [DOI: 10.3727/096368909x471242] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Within the emerging field of stem cells there is a need for an environment that can regulate cell activity, to slow down differentiation or proliferation, in vitro or in vivo while remaining invisible to the immune system. By creating a nanoenvironment surrounding PC12 cells, Schwann cells, and neural precursor cells (NPCs), we were able to control the proliferation, elongation, differentiation, and maturation in vitro. We extended the method, using self-assembling nanofiber scaffold (SAPNS), to living animals with implants in the brain and spinal cord. Here we show that when cells are placed in a defined system we can delay their proliferation, differentiation, and maturation depending on the density of the cell population, density of the matrix, and the local environment. A combination of SAPNS and young cells can be implanted into the central nervous system (CNS), eliminating the need for immunosuppressants.
Collapse
Affiliation(s)
- R. G. Ellis-Behnke
- Department of Anatomy, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
- State Key Lab for Brain & Cognitive Sciences, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Y. X. Liang
- Department of Anatomy, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
| | - J. Guo
- Department of Anatomy, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
| | - D. K. C. Tay
- Department of Anatomy, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
| | - G. E. Schneider
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - L. A. Teather
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - W. Wu
- Department of Anatomy, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
- State Key Lab for Brain & Cognitive Sciences, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
- Research Center of Reproduction, Development and Growth, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
| | - K. F. So
- Department of Anatomy, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
- State Key Lab for Brain & Cognitive Sciences, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
- Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong Li Ka Shing Faculty of Medicine, Pokfulam, Hong Kong SAR, China
| |
Collapse
|
55
|
Cell Guidance by 3D-Gradients in Hydrogel Matrices: Importance for Biomedical Applications. MATERIALS 2009. [PMCID: PMC5445751 DOI: 10.3390/ma2031058] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Concentration gradients of soluble and matrix-bound guidance cues in the extracellular matrix direct cell growth in native tissues and are of great interest for design of biomedical scaffolds and on implant surfaces. The focus of this review is to demonstrate the importance of gradient guidance for cells as it would be desirable to direct cell growth onto/into biomedical devices. Many studies have been described that illustrate the production and characterization of surface gradients, but three dimensional (3D)-gradients that direct cellular behavior are not well investigated. Hydrogels are considered as synthetic replacements for native extracellular matrices as they share key functions such as 2D- or 3D-solid support, fibrous structure, gas- and nutrition permeability and allow storage and release of biologically active molecules. Therefore this review focuses on current studies that try to implement soluble or covalently-attached gradients of growth factors, cytokines or adhesion sequences into 3D-hydrogel matrices in order to control cell growth, orientation and migration towards a target. Such gradient architectures are especially desirable for wound healing purposes, where defined cell populations need to be recruited from the blood stream and out of the adjacent tissue, in critical bone defects, for vascular implants or neuronal guidance structures where defined cell populations should be guided by appropriate signals to reach their proper positions or target tissues in order to accomplish functional repair.
Collapse
|
56
|
Wood MD, Borschel GH, Sakiyama-Elbert SE. Controlled release of glial-derived neurotrophic factor from fibrin matrices containing an affinity-based delivery system. J Biomed Mater Res A 2009; 89:909-18. [PMID: 18465825 DOI: 10.1002/jbm.a.32043] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This research evaluated the controlled release of glial-derived neurotrophic factor (GDNF) from an affinity-based delivery system (ABDS) as potential treatment for peripheral nerve injury. The ABDS consisted of a bidomain peptide containing a transglutaminase substrate, allowing crosslinking into fibrin matrices, and a heparin-binding domain based on the antithrombin-III heparin-binding domain, heparin, and GDNF, which was sequestered based on its heparin-binding affinity. The objective of this research was to determine the release rate and biological activity of GDNF released from the ABDS in vitro. The ratio of peptide to heparin was found to modulate the rate of GDNF release. The biological activity of GDNF released from the ABDS was assayed using chick dorsal root ganglia (DRGs) neurite extension. Neurite extension was equivalent for fibrin matrices containing the ABDS for all concentrations of GDNF tested versus DRGs grown with GDNF in the media. Furthermore, neurite extension was enhanced in fibrin matrices containing 100 ng/mL of GDNF with the ABDS versus matrices with GDNF at a simliar dose but no ABDS. These results suggest that GDNF can be retained and released in a biologically activity form from the ABDS, and thus this approach may prove useful for the treatment of peripheral nerve injury.
Collapse
Affiliation(s)
- Matthew D Wood
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63130, USA
| | | | | |
Collapse
|
57
|
Wood MD, Moore AM, Hunter DA, Tuffaha S, Borschel GH, Mackinnon SE, Sakiyama-Elbert SE. Affinity-based release of glial-derived neurotrophic factor from fibrin matrices enhances sciatic nerve regeneration. Acta Biomater 2009; 5:959-68. [PMID: 19103514 PMCID: PMC2678870 DOI: 10.1016/j.actbio.2008.11.008] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 10/20/2008] [Accepted: 11/19/2008] [Indexed: 12/13/2022]
Abstract
Glial-derived neurotrophic factor (GDNF) promotes both sensory and motor neuron survival. The delivery of GDNF to the peripheral nervous system has been shown to enhance regeneration following injury. In this study, we evaluated the effect of affinity-based delivery of GDNF from a fibrin matrix in a nerve guidance conduit on nerve regeneration in a 13 mm rat sciatic nerve defect. Seven experimental groups were evaluated which received GDNF or nerve growth factor (NGF) with the delivery system within the conduit, control groups excluding one or more components of the delivery system, and nerve isografts. Nerves were harvested 6 weeks after treatment for analysis by histomorphometry and electron microscopy. The use of the delivery system (DS) with either GDNF or NGF resulted in a higher frequency of nerve regeneration vs. control groups, as evidenced by a neural structure spanning the 13 mm gap. The GDNF DS and NGF DS groups were also similar to the nerve isograft group in measures of nerve fiber density, percent neural tissue and myelinated area measurements, but not in terms of total fiber counts. In addition, both groups contained a significantly greater percentage of larger diameter fibers, with GDNF DS having the largest in comparison to all groups, suggesting more mature neural content. The delivery of GDNF via the affinity-based delivery system can enhance peripheral nerve regeneration through a silicone conduit across a critical nerve gap and offers insight into potential future alternatives to the treatment of peripheral nerve injuries.
Collapse
Affiliation(s)
- Matthew D. Wood
- Department of Biomedical Engineering, Washington University, Campus Box 1097, One Brookings Drive, St. Louis, MO 63130, USA
| | - Amy M. Moore
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, Campus Box 8238, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Daniel A. Hunter
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, Campus Box 8238, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Sami Tuffaha
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, Campus Box 8238, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Gregory H. Borschel
- Department of Biomedical Engineering, Washington University, Campus Box 1097, One Brookings Drive, St. Louis, MO 63130, USA
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, Campus Box 8238, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Susan E. Mackinnon
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, Campus Box 8238, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Shelly E. Sakiyama-Elbert
- Department of Biomedical Engineering, Washington University, Campus Box 1097, One Brookings Drive, St. Louis, MO 63130, USA
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Washington University School of Medicine, Campus Box 8238, 660 South Euclid Avenue, St. Louis, MO 63110, USA
- Center for Materials Innovation, Washington University, Campus Box 1105, One Brookings Drive, St. Louis, MO 63130, USA
| |
Collapse
|
58
|
Janmey PA, Winer JP, Weisel JW. Fibrin gels and their clinical and bioengineering applications. J R Soc Interface 2009; 6:1-10. [PMID: 18801715 DOI: 10.1098/rsif.2008.0327] [Citation(s) in RCA: 434] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Fibrin gels, prepared from fibrinogen and thrombin, the key proteins involved in blood clotting, were among the first biomaterials used to prevent bleeding and promote wound healing. The unique polymerization mechanism of fibrin, which allows control of gelation times and network architecture by variation in reaction conditions, allows formation of a wide array of soft substrates under physiological conditions. Fibrin gels have been extensively studied rheologically in part because their nonlinear elasticity, characterized by soft compliance at small strains and impressive stiffening to resist larger deformations, appears essential for their function as haemostatic plugs and as matrices for cell migration and wound healing. The filaments forming a fibrin network are among the softest in nature, allowing them to deform to large extents and stiffen but not break. The biochemical and mechanical properties of fibrin have recently been exploited in numerous studies that suggest its potential for applications in medicine and bioengineering.
Collapse
Affiliation(s)
- Paul A Janmey
- Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, 3340 Smith Walk, Philadelphia, PA 19104, USA.
| | | | | |
Collapse
|
59
|
Willerth SM, Rader A, Sakiyama-Elbert SE. The effect of controlled growth factor delivery on embryonic stem cell differentiation inside fibrin scaffolds. Stem Cell Res 2008; 1:205-18. [PMID: 19383401 DOI: 10.1016/j.scr.2008.05.006] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 05/23/2008] [Accepted: 05/29/2008] [Indexed: 01/06/2023] Open
Abstract
The goal of this project was to develop 3-D biomaterial scaffolds that present cues to direct the differentiation of embryonic stem (ES) cell-derived neural progenitor cells, seeded inside the scaffolds, into mature neural phenotypes, specifically neurons and oligodendrocytes. Release studies were performed to determine the appropriate conditions for retention of neurotrophin-3 (NT-3), sonic hedgehog, and platelet-derived growth factor (PDGF) by an affinity-based delivery system incorporated into fibrin scaffolds. Embryoid bodies containing neural progenitors were formed from mouse ES cells, using a 4-/4+ retinoic acid treatment protocol, and then seeded inside fibrin scaffolds containing the drug delivery system. This delivery system was used to deliver various growth factor doses and combinations to the cells seeded inside the scaffolds. Controlled delivery of NT-3 and PDGF simultaneously increased the fraction of neural progenitors, neurons, and oligodendrocytes while decreasing the fraction of astrocytes obtained compared to control cultures seeded inside unmodified fibrin scaffolds with no growth factors present in the medium. These results demonstrate that such a strategy can be used to generate an engineered tissue for the potential treatment of spinal cord injury and could be extended to the study of differentiation in other tissues.
Collapse
Affiliation(s)
- Stephanie M Willerth
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, USA
| | | | | |
Collapse
|
60
|
Willerth SM, Sakiyama-Elbert SE. Cell therapy for spinal cord regeneration. Adv Drug Deliv Rev 2008; 60:263-76. [PMID: 18029050 DOI: 10.1016/j.addr.2007.08.028] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Accepted: 08/22/2007] [Indexed: 01/09/2023]
Abstract
This review presents a summary of the various types of cellular therapy used to treat spinal cord injury. The inhibitory environment and loss of axonal connections after spinal cord injury pose many obstacles to regenerating the lost tissue. Cellular therapy provides a means of restoring the cells lost to the injury and could potentially promote functional recovery after such injuries. A wide range of cell types have been investigated for such uses and the advantages and disadvantages of each cell type are discussed along with the research studying each cell type. Additionally, methods of delivering cells to the injury site are evaluated. Based on the current research, suggestions are given for future investigation of cellular therapies for spinal cord regeneration.
Collapse
|
61
|
Willerth SM, Faxel TE, Gottlieb DI, Sakiyama-Elbert SE. The effects of soluble growth factors on embryonic stem cell differentiation inside of fibrin scaffolds. Stem Cells 2007; 25:2235-44. [PMID: 17585170 PMCID: PMC2637150 DOI: 10.1634/stemcells.2007-0111] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The goal of this research was to determine the effects of different growth factors on the survival and differentiation of murine embryonic stem cell-derived neural progenitor cells (ESNPCs) seeded inside of fibrin scaffolds. Embryoid bodies were cultured for 8 days in suspension, retinoic acid was applied for the final 4 days to induce ESNPC formation, and then the EBs were seeded inside of three-dimensional fibrin scaffolds. Scaffolds were cultured in the presence of media containing different doses of the following growth factors: neurotrophin-3 (NT-3), basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF)-AA, ciliary neurotrophic factor, and sonic hedgehog (Shh). The cell phenotypes were characterized using fluorescence-activated cell sorting and immunohistochemistry after 14 days of culture. Cell viability was also assessed at this time point. Shh (10 ng/ml) and NT-3 (25 ng/ml) produced the largest fractions of neurons and oligodendrocytes, whereas PDGF (2 and 10 ng/ml) and bFGF (10 ng/ml) produced an increase in cell viability after 14 days of culture. Combinations of growth factors were tested based on the results of the individual growth factor studies to determine their effect on cell differentiation. The incorporation of ESNPCs and growth factors into fibrin scaffolds may serve as potential treatment for spinal cord injury.
Collapse
Affiliation(s)
| | - Tracy E. Faxel
- Department of Biomedical Engineering, Washington University in St. Louis
| | - David I. Gottlieb
- Department of Anatomy and Neurobiology, Washington University in St. Louis
| | - Shelly E. Sakiyama-Elbert
- Department of Biomedical Engineering, Washington University in St. Louis
- Center for Materials Innovation, Washington University in St. Louis
- To whom correspondence should be addressed: Shelly Sakiyama-Elbert, Department of Biomedical Engineering, Washington University, Campus Box 1097, One Brookings Drive, St. Louis, MO 63130,
| |
Collapse
|
62
|
Chung YI, Ahn KM, Jeon SH, Lee SY, Lee JH, Tae G. Enhanced bone regeneration with BMP-2 loaded functional nanoparticle-hydrogel complex. J Control Release 2007; 121:91-9. [PMID: 17604871 DOI: 10.1016/j.jconrel.2007.05.029] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Revised: 05/16/2007] [Accepted: 05/23/2007] [Indexed: 11/28/2022]
Abstract
As an efficient sustained release system of BMP-2, a functional nanoparticle-hydrogel complex, composed of heparin-functionalized nanoparticles and fibrin gel, was developed and used as a bone graft. In vivo bone formation was evaluated by soft X-ray, histology, alkaline phosphatase (ALP) activity, immunostaining, and mineral content analysis, based on the rat calvarial critical size defect model. Significantly improved and effective bone regeneration was achieved with the recombinant BMP-2 (4 mug) loaded nanoparticle-fibrin gel complex, as compared to bare fibrin gel, the nanoparticle-fibrin gel complex without BMP-2, or even the BMP-2 loaded fibrin gel. These improvements included areas such as radiodensity, the bone-specific ALP activity, the osteocalcin immunoreactivity, and the ratios of calcium and phosphate contents with respect to normal bone in the regenerated bone area. The remodeling process of new bone developed with BMP-2 was significantly enhanced, and more mature and highly-mineralized bone was obtained by utilizing the functional nanoparticle-hydrogel complex. These results indicate that the nanoparticle-fibrin gel complex can be a promising candidate for a new bone defect replacement matrix, and an enhanced BMP-2 carrier.
Collapse
Affiliation(s)
- Yong-Il Chung
- Research Center for Biomolecular Nanotechnology and Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju, 500-712, Republic of Korea
| | | | | | | | | | | |
Collapse
|
63
|
Willerth SM, Sakiyama-Elbert SE. Approaches to neural tissue engineering using scaffolds for drug delivery. Adv Drug Deliv Rev 2007; 59:325-38. [PMID: 17482308 PMCID: PMC1976339 DOI: 10.1016/j.addr.2007.03.014] [Citation(s) in RCA: 214] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2006] [Accepted: 03/28/2007] [Indexed: 02/07/2023]
Abstract
This review seeks to give an overview of the current approaches to drug delivery from scaffolds for neural tissue engineering applications. The challenges presented by attempting to replicate the three types of nervous tissue (brain, spinal cord, and peripheral nerve) are summarized. Potential scaffold materials (both synthetic and natural) and target drugs are discussed with the benefits and drawbacks given. Finally, common methods of drug delivery, including degradable/diffusion-based delivery systems, affinity-based delivery systems, immobilized drug delivery systems, and electrically controlled drug delivery systems, are examined and critiqued. Based on the current body of work, suggestions for future directions of research in the field of neural tissue engineering are presented.
Collapse
Affiliation(s)
| | - Shelly E. Sakiyama-Elbert
- Department of Biomedical Engineering, Washington University in St. Louis
- Center for Materials Innovation, Washington University in St. Louis
- * To whom correspondence should be addressed: Shelly Sakiyama-Elbert, Department of Biomedical Engineering, Washington University, Campus Box 1097, One Brookings Drive, St. Louis, MO 63130,
| |
Collapse
|