Two Generations Of Synthetic Membranes For Biological/medical Applications
amphiphilic membranes; amphiphilic networks; biocompatibility; diffusion; domains; Glucose; immunoisolation; insulin diffusion; isobutylene; living carbocationic polymerization; membranes; polyisobutylene; Polymer Science; polymers; selective permeability; tricomponent
Two generations of amphiphilic membranes synthesized in our laboratories for biologicaUniedical applications are highlighted. Recent results obtained with representative 2nd generation membranes designed specifically for immunoencapsulation of pancreatic islets and cells, are Summarized. The latter tri-component membranes comprise well-defined hydrophilic poly(ethylene glycol) and hydrophobic/oxyphilic polydimethylsiloxane segments crosslinked by oxyphilic polycyclosiloxane domains, which also provide reinforcement. Select membranes are demonstrated to allow the diffusion of glucose and insulin but prevent the permeation of immunoglobulin G. These membranes remain permeable despite long incubation in IgG solution.
Kennedy J P; Rosenthal K S; Kashibhatla B
Designed Monomers and Polymers
2004
2004
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1163/1568555042474112" target="_blank" rel="noreferrer noopener">10.1163/1568555042474112</a>
Cholesterol-Peptide Hybrids to Form Liposome-Like Vesicles for Gene Delivery
condensation; dna; histidine; nanoparticles; oligopeptides; polymers; prospects; Science & Technology - Other Topics; systems; therapy; vectors
In this paper, four amphiphilic cholesterol-peptide conjugates (Ch-R5H5, Ch-R3H3, Ch-R5 and Ch-R5) were designed and synthesized, and their properties in gene delivery were evaluated in vitro with an aim of developing more efficient gene delivery carriers. These amphiphilic cholesterol-peptide conjugates are composed of hydrophobic cholesterol and positively charged peptides. They were able to self-assemble into micelles at low concentrations and their critical micelle concentrations in phosphate buffered saline (pH 7.4) are <= 85 mu g/mL. Amphiphilic cholesterol-peptide conjugates condensed DNA more efficiently than a hydrophilic cationic oligoarginine (R10) peptide with no hydrophobic segment. Their transfection efficiencies were at least two orders of magnitude greater than that of R10 peptide in HEK-293 cells. Moreover, the introduction of histidine residues in cholesterol-peptide conjugates led to higher gene expression efficiency compared with cholesterol-peptides without histidine (Ch-R5 and Ch-R3), and the luciferase expression level was comparable or even higher than that induced by PEI at its optimal N/P ratio. In particular, Ch-R5H5 condensed DNA into smaller nanoparticles than Ch-R3H3 at higher N/P ratios, and the minimum size of Ch-R5H5/DNA complexes was 180 nm with zeta potential of 23 mV, achieved at the N/P ratio of 30. This liposome-like vesicle may be a promising gene delivery carrier for intravenous therapy.
Tang Q; Cao B; Wu H Y; Cheng G
PLOS ONE
2013
2013-01
Journal Article
<a href="http://doi.org/10.1371/journal.pone.0054460" target="_blank" rel="noreferrer noopener">10.1371/journal.pone.0054460</a>
Design and assessment of a tissue-engineered model of human phalanges and a small joint.
*Bioartificial Organs; *Biomimetic Materials; *Finger Joint; *Finger Phalanges; *Tissue Engineering; Animals; Biological; Bone and Bones; Cartilage; Cattle; Humans; Lactic Acid; Mice; Models; Nude; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Polymers; Tendons
OBJECTIVES: To develop models of human phalanges and small joints by suturing different cell-polymer constructs that are then implanted in athymic (nude) mice. DESIGN: Models consisted of bovine periosteum, cartilage, and/or tendon cells seeded onto biodegradable polymer scaffolds of either polyglycolic acid (PGA) or copolymers of PGA and poly-L-lactic acid (PLLA) or poly-epsilon-caprolactone (PCL) and PLLA. Constructs were fabricated to produce a distal phalanx, middle phalanx, or distal interphalangeal joint. SETTING AND SAMPLE POPULATION: Studies of more than 250 harvested implants were conducted at the Northeastern Ohio Universities College of Medicine. EXPERIMENTAL VARIABLE: Polymer scaffold, cell type, and implantation time were examined. OUTCOME MEASURE: Tissue-engineered specimens were characterized by histology, transmission electron microscopy, in situ hybridization, laser capture microdissection and qualitative and quantitative polymerase chain reaction analysis, magnetic resonance microscopy, and X-ray microtomography. RESULTS: Over periods to 60 weeks of implantation, constructs developed through vascularity from host mice; formed new cartilage, bone, and/or tendon; expressed characteristic genes of bovine origin, including type I, II and X collagen, osteopontin, aggrecan, biglycan, and bone sialoprotein; secreted corresponding proteins; responded to applied mechanical stimuli; and maintained shapes of human phalanges with small joints. CONCLUSION: Results give insight into construct processes of tissue regeneration and development and suggest more complete tissue-engineered cartilage, bone, and tendon models. These should have significant future scientific and clinical applications in medicine, including their use in plastic surgery, orthopaedics, craniofacial reconstruction, and teratology.
Landis W J; Jacquet R; Hillyer J; Lowder E; Yanke A; Siperko L; Asamura S; Kusuhara H; Enjo M; Chubinskaya S; Potter K; Isogai N
Orthodontics & craniofacial research
2005
2005-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1111/j.1601-6343.2005.00353.x" target="_blank" rel="noreferrer noopener">10.1111/j.1601-6343.2005.00353.x</a>