Preparation of well-defined calcium cross-linked alginate films for the prevention of surgical adhesions.

Abdominal adhesions are one of the major problems associated with abdominal surgeries or abdominal trauma. There are many different therapeutic options to prevent these adhesions, for example, the application of barrier films made of biodegradable polymers like alginate. For many application relevant parameters (mechanical stability, elasticity, erosion, and mucoadhesivity of the films), the extent of cross-linking with divalent cations, such as calcium, is essential to obtain alginate films with clinically ideal properties.

Heterobifunctional poly(ethylene glycol) derivatives for the surface modification of gold nanoparticles toward bone mineral targeting.

Heterobifunctional poly(ethylene glycol)s can be used for many biomedical applications ranging from solubility enhancement of hardly soluble compounds to surface modification of medical devices. In order to modify gold nanoparticles as model particles for drug targeting applications, PEG derivatives are synthesized that possess a high affinity for gold surfaces, namely a thioalkyl function, known to form stable monolayers on gold. Additionally a bisphosphonate function is introduced in the PEG molecule to allow targeting of hydroxyapatite rich tissues, like bone.

Size-dependent release of fluorescent macromolecules and nanoparticles from radically cross-linked hydrogels.

Hydrogels play an important role in drug delivery and tissue engineering applications due to their excellent biocompatibility and their variable mechanical and physical properties, which allow their optimization for many different aspects of the intended use. In this study, we examined the suitability of poly(ethylene glycol) (PEG)-based hydrogels as release systems for nanometer-sized drugs or drug carriers, like nanoparticles, using the radically cross-linkable oligo(poly(ethylene glycol)fumarate) (OPF) together with two cross-linking agents. Different fluorescent nanoparticulate probes with respect to size and physical structure were incorporated in the cross-linked hydrogels, and the obtained release profiles were correlated with the physical properties and the chemical structure of the gels, indicating a strong dependence of the release on the chosen PEG prepolymers.

Matrices and scaffolds for protein delivery in tissue engineering.

The tissue engineering of functional tissues depends on the development of suitable scaffolds to support three dimensional cell growth. To improve the properties of the scaffolds, many cell carriers serve dual purposes; in addition to providing cell support, cutting-edge scaffolds biologically interact with adhering and invading cells and effectively guide cellular growth and development by releasing bioactive proteins like growth factors and cytokines. To design controlled release systems for certain applications, it is important to understand the basic principles of protein delivery as well as the stability of each applied biomolecule.

Customized PEG-derived copolymers for tissue-engineering applications.

PEG-containing copolymers play a prominent role as biomaterials for different applications ranging from drug delivery to tissue engineering. These custom-designed materials offer enormous possibilities to change the overall characteristics of biomaterials by improving their biocompatibility and solubility, as well as their ability to crystallize in polymer blends and to resist protein adsorption. This article demonstrates various principles of PEG-based material design that are applied to fine tune the properties of biomaterials for different tissue engineering applications.

Transforming growth factor-beta 1 release from oligo(poly(ethylene glycol) fumarate) hydrogels in conditions that model the cartilage wound healing environment.

This research demonstrates that controlled material degradation and transforming growth factor-beta1 (TGF-beta1) release can be achieved by encapsulation of TGF-beta1-loaded gelatin microparticles within the biodegradable polymer oligo(poly(ethylene glycol) fumarate) (OPF), so that these microparticles function as both a digestible porogen and a delivery vehicle. Release studies performed with non-encapsulated microparticles confirmed that at normal physiological pH, TGF-beta1 complexes with acidic gelatin, resulting in slow release rates. At pH 4.