Improved delivery of PLGA microparticles and microparticle-cell scaffolds in clinical needle gauges using modified viscosity formulations.

Polymer microparticles are widely used as acellular drug delivery platforms in regenerative medicine, and have emerging potential as cellular scaffolds for therapeutic cell delivery. In the clinic, PLGA microparticles are typically administered intramuscularly or subcutaneously, with the clinician and clinical application site determining the precise needle gauge used for delivery. Here, we explored the role of needle diameter in microparticle delivery yield, and develop a modified viscosity formulation to improve microparticle delivery across a range of clinically relevant needle diameters.

Design of maleimide-functionalised electrodes for covalent attachment of proteins through free surface cysteine groups.

Mixed two-component monolayers on glassy carbon are prepared by electrochemical oxidation of N-(2-aminoethyl)acetamide and mono-N-Boc-hexamethylenediamine in mixed solution. Subsequent N-deprotection, amide coupling and solid-phase synthetic steps lead to electrode-surface functionalisation with maleimide, with controlled partial coverage of this cysteine-binding group at appropriate dilution for covalent immobilisation of a model redox-active protein, cytochrome c, with high coverage (≈7.5 pmol cm(-2) ).

Mucoadhesive polymer films for tissue retraction in laparoscopic surgery: Ex-vivo study on their mechanical properties.

Safe and effective manipulation of soft tissue during laparoscopic procedures can be achieved by the use of mucoadhesive polymer films. A series of novel adhesive polymer films were formulated in house based on either Carbopol or Chitosan modified systems. The mechanical properties of the polymers and their adherence to bowel were evaluated using ex-vivo pig bowel immersed in 37°C water bath and connected to an Instron tensiometer.

The effect of dilute solution properties on poly(vinyl alcohol) films.

Films are commonly prepared by solvent casting and accordingly it is important to investigate the relationship between the properties of the polymeric solution and the resultant solid-state properties of the film. Therefore the objective of this work was to characterise the rheological properties of aqueous solutions of PVA, containing defined co-solvents, and to relate these properties to the resultant mechanical and swelling properties of films cast from these solutions. Casting solutions were prepared using two concentrations of two molecular weights of PVA within a range of cosolvent systems.

Ex vivo comparison of mechanical versus thermal chondroplasty: assessment of tissue effect at the surgical endpoint.

Purpose: The purpose of this study was to evaluate tissue effect (tissue removal plus underlying cell death) of two chondroplasty techniques: mechanical debridement (MD) using a rotary shaver blade and thermal chondroplasty using radiofrequency energy (RFE).

Methods: Forty-eight human chondromalacic cartilage samples were treated with either MD or RFE. Pre- and post-treatment arthroscopic images of the cartilage surface were recorded.

An ex vivo thermal chondroplasty model: the association of a char-like layer and underlying cell death.

Purpose: The purpose of this study was to evaluate the relation between the char-like layer observed during radiofrequency energy (RFE) treatment of cartilage and the depth of underlying cell death.

Methods: Healthy adult bovine patellae were treated with a monopolar RFE probe ex vivo at generator settings of 20, 30, 40, 50, 60, 80, and 110 in cut mode. The presence or absence of a char-like layer and visual electrical discharge was noted.

Determination of factors influencing tissue effect of thermal chondroplasty: an ex vivo investigation.

Purpose: Scientific investigation of thermal chondroplasty using radiofrequency energy (RFE) is confounded by multiple factors associated with the technique. Our purpose was to determine the relative importance of the following factors on tissue effect (depth of tissue debridement plus depth of underlying cell death) of thermal chondroplasty: probe design, generator power setting, speed, force, and number of passes of the probe over treated tissue. We hypothesized the relative importance of these factors would be (from most to least important) power, passes, speed, force, and design.