Surface modification of PdlLGA microspheres with gelatine methacrylate: Evaluation of adsorption, entrapment, and oxygen plasma treatment approaches.

Unlabelled: Injectable poly (dl-lactic-co-glycolic acid) (PdlLGA) microspheres are promising candidates as biodegradable controlled release carriers for drug and cell delivery applications; however, they have limited functional groups on the surface to enable dense grafting of tissue specific biocompatible molecules. In this study we have evaluated surface adsorption, entrapment and oxygen plasma treatment as three approaches to modify the surfaces of PdlLGA microspheres with gelatine methacrylate (gel-MA) as a biocompatible and photo cross-linkable macromolecule. Time of flight secondary ion mass spectroscopy (TOF SIMS) and X-ray photoelectron spectroscopy (XPS) were used to detect and quantify gel-MA on the surfaces.

Physicomechanical properties of sintered scaffolds formed from porous and protein-loaded poly(DL-lactic-co-glycolic acid) microspheres for potential use in bone tissue engineering.

An injectable poly(DL-lactic-co-glycolic acid) (PLGA) system comprising both porous and protein-loaded microspheres capable of forming porous scaffolds at body temperature was developed for tissue regeneration purposes. Porous and non-porous (lysozyme loaded) PLGA microspheres were formulated to represent 'low molecular weight' 22-34 kDa, 'intermediate molecular weight' (IMW) 53 kDa and 'high molecular weight' 84-109 kDa PLGA microspheres. The respective average size of the microspheres was directly related to the polymer molecular weight.

Injectable and porous PLGA microspheres that form highly porous scaffolds at body temperature.

Injectable scaffolds are of interest in the field of regenerative medicine because of their minimally invasive mode of delivery. For tissue repair applications, it is essential that such scaffolds have the mechanical properties, porosity and pore diameter to support the formation of new tissue. In the current study, porous poly(dl-lactic acid-co-glycolic acid) (PLGA) microspheres were fabricated with an average size of 84±24μm for use as injectable cell carriers.

Investigation of localized delivery of diclofenac sodium from poly(D,L-lactic acid-co-glycolic acid)/poly(ethylene glycol) scaffolds using an in vitro osteoblast inflammation model.

Nonunion fractures and large bone defects are significant targets for osteochondral tissue engineering strategies. A major hurdle in the use of these therapies is the foreign body response of the host. Herein, we report the development of a bone tissue engineering scaffold with the ability to release anti-inflammatory drugs, in the hope of evading this response.

The osteogenic response of mesenchymal stem cells to an injectable PLGA bone regeneration system.

The enrichment of substrates/surfaces with selected functional groups, methyl (-CH3), allyl amine (-NH2), allyl alcohol (-OH) and acrylic acid (-COOH), can be used to trigger mesenchymal stem (MSC) cell differentiation into specified lineages, minimising the need for exogenous biological supplementation. We present the successful translation of this research phenomenon to an injectable two phase injectable PLGA system, utilising plasma techniques, for the repair of bone defects. Modified microspheres were characterised using water contact angel (WCA), X-ray Photon Spectroscopy (XPS) and scanning electron microscopy (SEM).

Development of a porous poly(DL-lactic acid-co-glycolic acid)-based scaffold for mastoid air-cell regeneration.

Objectives/hypothesis: To develop a porous, biodegradable scaffold for mastoid air-cell regeneration.

Study Design: In vitro development of a temperature-sensitive poly(DL-lactic acid-co-glycolic acid)/poly(ethylene glycol) (PLGA/PEG) scaffold tailored for this application.

Methods: Human mastoid bone microstructure and porosity were investigated using micro-computed tomography.

PLGA/PEG-hydrogel composite scaffolds with controllable mechanical properties.

Biodegradable polymer scaffolds have great potential for regenerative medicine applications such as the repair of musculoskeletal tissues. Here, we describe the development of scaffolds that blend hydrogel components with thermoplastic materials, combining the unique properties of both components to create mouldable formulations. This study focuses on the structural and mechanical properties of the composite scaffolds, produced by combining temperature-sensitive poly(DL-lactic acid-co-glycolic acid) (PLGA)/poly(ethylene glycol) (PEG) particles with a hydrogel component [Pluronic F127, fibrin or hyaluronic acid (HyA)].

Recapitulation of tumor heterogeneity and molecular signatures in a 3D brain cancer model with decreased sensitivity to histone deacetylase inhibition.

Introduction: Physiologically relevant pre-clinical ex vivo models recapitulating CNS tumor micro-environmental complexity will aid development of biologically-targeted agents. We present comprehensive characterization of tumor aggregates generated using the 3D Rotary Cell Culture System (RCCS).

Methods: CNS cancer cell lines were grown in conventional 2D cultures and the RCCS and comparison with a cohort of 53 pediatric high grade gliomas conducted by genome wide gene expression and microRNA arrays, coupled with immunohistochemistry, ex vivo magnetic resonance spectroscopy and drug sensitivity evaluation using the histone deacetylase inhibitor, Vorinostat.

Controlled release of BMP-2 from a sintered polymer scaffold enhances bone repair in a mouse calvarial defect model.

Sustained and controlled delivery of growth factors, such as bone morphogenetic protein 2 (BMP-2), from polymer scaffolds has excellent potential for enhancing bone regeneration. The present study investigated the use of novel sintered polymer scaffolds prepared using temperature-sensitive PLGA/PEG particles. Growth factors can be incorporated into these scaffolds by mixing the reconstituted growth factor with the particles prior to sintering.