In Vitro Studies on Regulation of Osteogenic Activities by Electrical Stimulus on Biodegradable Electroactive Polyelectrolyte Multilayers

Photo-immobilization of bone morphogenic protein 2 on PLGA/HA nanocomposites to enhance the osteogenesis of adipose-derived stem cells

Poly(lactide-co-glycolide) and nano-hydroxyapatite composites are surface-modified with BMP-2 via photo-reactive gelatin to make the composites exhibit excellent bioactivities for the adhesion, proliferation and osteogenic differentiation of ADSCs.

Synthesis of well-defined carboxyl poly(ε-caprolactone) by fine-tuning the protection group

Carboxyl functionalized polycaprolactone with a well-defined structure was synthesized via ring-opening polymerization (ROP) of substituted caprolactone monomer and acidic hydrolysis.

Conducting polymer-based multilayer films for instructive biomaterial coatings

Aim:

To demonstrate the design, fabrication and testing of conformable conducting biomaterials that encourage cell alignment.

Materials & methods:

Thin conducting composite biomaterials based on multilayer films of poly(3.4-ethylenedioxythiophene) derivatives, chitosan and gelatin were prepared in a layer-by-layer fashion. Fibroblasts were observed with fluorescence microscopy and their alignment (relative to the dipping direction and direction of electrical current passed through the films) was determined using ImageJ.

Results:

Fibroblasts adhered to and proliferated on the films. Fibroblasts aligned with the dipping direction used during film preparation and this was enhanced by a DC current.

Conclusion:

We report the preparation of conducting polymer-based films that enhance the alignment of fibroblasts on their surface which is an important feature of a variety of tissues.

Lay abstract: Cells inhabit environments known as the extracellular matrix (ECM) which consists of a mixture of different biomolecules, and the precise composition and topographical properties are different in different tissues (e.g., bone, brain, muscle, skin). Cells interact intimately with the ECM, not only constructing the biomolecules, but assist its organization in 3D space, and its degradation (which is important for tissue remodeling); reciprocally, cells respond to the ECM (e.g., by modifying their size, shape, etc). Cellular alignment is observed in organs and tissues such as bones, muscles and skin, and this alignment is important for the healthy functioning of the organ/tissue. Here, we present a novel method of aligning cells on biomaterials, simply by applying an electrical current through the biomaterial.

Autologous osteoblast transplantation, an innovative method of bone defect treatment: role of a tissue and cell bank in the process

BACKGROUND

The idea of cell treatment of various diseases and medical conditions has become very popular. Some procedures are well established, as is autologous chondrocyte implantation, whereas others are still in the process of early development, laboratory experiments, and some clinical trials.

METHODS

This report is devoted to an example of an emerging cell treatment: bone augmentation with the use of autologous cells and its legal and technical background. Various requirements set by law must be met by tissue banks performing cell seeding of grafts. In Europe, the requirements are described in directives 2004/23/EC, 2006/17/EC, 2006/86/EC, and in the regulation 2007/1394/EC.

RESULTS

Revitalization of biostatic allografts gives new, promising tools for creation of functional parts of organs; brings the methodology used in tissue banks closer to tissue engineering; places the enterprise in the mainstream of advanced biotechnology; allows the full potential of tissue allografts; and opens a new, large area for clinical and laboratory research. Cell and tissue processing also have a financial impact on the treatment: it produces additional expenditures.

CONCLUSIONS

Clinical effectiveness will be the most decisive factor of whether this innovative treatment will be applied in a particular type of medical condition. From a tissue establishment perspective, the most important issue is to develop a procedure that ensures safety for the patient in graft quality terms.

Layer-by-layer assembly for biomedical applications in the last decade

In the past two decades, the design and manufacture of nanostructured materials has been of tremendous interest to the scientific community for their application in the biomedical field. Among the available techniques, layer-by-layer (LBL) assembly has attracted considerable attention as a convenient method to fabricate functional coatings. Nowadays, more than 1000 scientific papers are published every year, tens of patents have been deposited and some commercial products based on LBL technology have become commercially available. LBL presents several advantages, such as (1): a precise control of the coating properties; (2) environmentally friendly, mild conditions and low-cost manufacturing; (3) versatility for coating all available surfaces; (4) obtainment of homogeneous film with controlled thickness; and (5) incorporation and controlled release of biomolecules/drugs. This paper critically reviews the scientific challenge of the last 10 years--functionalizing biomaterials by LBL to obtain appropriate properties for biomedical applications, in particular in tissue engineering (TE). The analysis of the state-of-the-art highlights the current techniques and the innovative materials for scaffold and medical device preparation that are opening the way for the preparation of LBL-functionalized substrates capable of modifying their surface properties for modulating cell interaction to improve substitution, repair or enhancement of tissue function.

Biodegradable Microcarriers of Poly(Lactide-co-Glycolide) and Nano-Hydroxyapatite Decorated with IGF-1 via Polydopamine Coating for Enhancing Cell Proliferation and Osteogenic Differentiation

In this study, insulin-like growth factor 1 (IGF-1) was successfully immobilized on the poly(lactide-co-glycolide)/hydroxyapatite (PLGA/HA) and pure PLGA microcarriers via polydopamine (pDA). The results demonstrated that the pDA layer facilitated simple and highly efficient immobilization of peptides on the microcarriers within 20 min. Mouse adipose-derived stem cells (ADSCs) attachment and proliferation on IGF-1-immobilized microcarriers were much higher than non-immobilized ones. More importantly, the IGF-1-immobilized PLGA/HA microcarriers significantly increased alkaline phosphatase (ALP) activity and expression of osteogenesis-related genes of ADSCs. Therefore, it is considered that the IGF-1-decorated PLGA/HA microcarriers will be of great value in the bone tissue engineering.

Electrical stimulation of human mesenchymal stem cells on biomineralized conducting polymers enhances their differentiation towards osteogenic outcomes

Tissue scaffolds allowing the behaviour of the cells that reside on them to be controlled are of particular interest for tissue engineering.