Layer-by-layer coated digitally encoded microcarriers for quantification of proteins in serum and plasma.

The "layer-by-layer" (LbL) technology has been widely investigated for the coating of flat substrates and capsules with polyelectrolytes. In this study, LbL polyelectrolyte coatings applied at the surface of digitally encoded microcarriers were evaluated for the quantitative, sensitive, and simultaneous detection of proteins in complex biological samples like serum, plasma, and blood. LbL coated microcarriers were therefore coupled to capture antibodies, which were used as capture agents for the detection of tumor necrosis factor (TNF-alpha), P24, and follicle stimulating hormone (FSH).

Anomalous photobleaching in fluorescence recovery after photobleaching measurements due to excitation saturation--a case study for fluorescein.

In this study we examine the implications of excitation saturation on fluorescence recovery after photobleaching (FRAP) experiments. In particular we present both experimental and theoretical evidence that fluorescein, one of the most frequently used fluorophores in FRAP, does not always comply with the basic assumptions that are made in many FRAP models: an invariant bleaching illumination intensity distribution (BID) in combination with first-order photobleaching kinetics. High light intensity levels, which are typical for the photobleaching phase of FRAP experiments, can cause excitation saturation of fluorescein in the excited triplet state.

Self-exploding lipid-coated microgels.

Self-exploding microparticles show potential for advanced delivery of certain therapeutics. This study evaluates (1) whether degrading biodegradable dextran hydroxyethyl methacrylate (dex-HEMA) microgels can be coated by a lipid membrane and (2) whether the surrounding membrane can be ruptured by the increasing swelling pressure of the degrading microgel. We found that adsorption of charged liposomes to oppositely charged dex-HEMA microgels provides efficient coating of the microgels, whereby microparticles with a "core-shell" structure were clearly obtained.

"Programmed polymeric devices" for pulsed drug delivery.

Pharmaceutical research strives to design drug delivery systems that respond to therapeutic needs. Considering the facts that physiologic parameters (e.g.

Tailoring the swelling pressure of degrading dextran hydroxyethyl methacrylate hydrogels.

Swelling pressure measurements were performed on degrading dextran hydroxyethyl methacrylate (dex-HEMA) hydrogels. In these networks, the cross-links are hydrolyzable carbonate ester bonds formed between methacrylate groups and dextran molecules. It is demonstrated that dex-HEMA gels made in the presence of a known amount of free dextran chains exhibit osmotic properties similar to those of partially degraded dex-HEMA gels.

A comparison between the use of dynamic mechanical analysis and oscillatory shear rheometry for the characterisation of hydrogels.

In this study the use of dynamic mechanical analysis (DMA) for the mechanical characterisation of pharmaceutical hydrogels was evaluated. DMA was used in two different modes, the "controlled force" and the "multi-strain" (MS). The results obtained on dextran methacrylate hydrogels of various compositions were compared to those obtained using an oscillatory shear rheometer.