Preparation and characterization of novel polymeric microcapsules for live cell encapsulation and therapy

Abstract

A graphical method for analyzing enzyme data to obtain kinetic parameters, and to identify the types of inhibition and the enzyme mechanisms, is described. The method consists of plotting experimental data as nu/(V0 - nu) vs 1/(I) at different substrate concentrations. I is the inhibitor concentration; V0 and nu are the rates of enzyme reaction attained by the system in the presence of a fixed amount of substrate, and in the absence and presence of inhibitor, respectively. Complete inhibition gives straight lines that go through the origin; partial inhibition gives straight lines that converge on the 1-I axis, at a point away from the origin. For competitive inhibition, the slopes of the lines increase with increasing-substrate concentration; with noncompetitive inhibition, the slopes are independent of substrate concentration; with uncompetitive inhibition, the slopes of the lines decrease with increasing substrate concentrations. The kinetic parameters, Km, Ki, Ki', and beta (degree of partiality) can best be determined from respective secondary plots of slope and intercept vs substrate concentration, for competitive and noncompetitive inhibition mechanism or slope and intercept vs reciprocal substrate concentration for uncompetitive inhibition mechanism. Functional consequencs of these analyses are represented in terms of specific enzyme-inhibitor systems.

Reaction of chitosan with genipin and its fluorogenic attributes for potential microcapsule membrane characterization

“…30 -32 Recently, a novel genipin crosslinked alginate-chitosan microcapsule formulation that has potentials for cell encapsulation and delivery was described. 33 This study further explores the reaction between chitosan and genipin. Results show that this reaction created a new product with fluorescent characteristics that has potential in microcapsule research, a new approach that has not yet been investigated.…”

“…33 Briefly, droplets of a sodium alginate solution (15 mg/mL) were generated by an encapsulator (Inotech Corp.) and gelled in a stirred solution of 0.1M CaCl 2 . The Ca-alginate beads were then coated for 30 min in a chitosan solution of 10 mg/mL containing 0.1M CaCl 2 , producing alginate-chitosan (AC) microcapsules.…”

Hydrogel Matrix Entrapping PLGA-Paclitaxel Microspheres: Drug Delivery with Near Zero-Order Release and Implantability Advantages for Malignant Brain Tumour Chemotherapy

“…In addition, the matrix could act as a barrier to drug diffusion from the microspheres and thus could inhibit the initial burst. One such matrix could be alginate, a natural polysaccharide derived from seaweed and algae that has realized numerous applications in the microencapsulation of cells (29) and biomolecules, tissue engineering (30) and drug delivery (31,32) due to its biocompatibility and hydrogel-forming abilities. Alginates undergo instantaneous gelation under mild reaction conditions in the presence of divalent cations such as Ca 2+ and form cross-linked threedimensional hydrogel matrices.…”

Characterization of a bioactive fiber scaffold with entrapped HUVECs in coaxial electrospun core-shell fiber

“…Therefore, the production of bioactive or biohybrid materials containing entrapped cells has been actively pursued. [6][7][8][9][10] Electrospinning has been widely used to produce fibrous scaffolds that are three-dimensional and porous utilizing both natural and synthetic polymers. The diameters of the electrospun fibers range from tens of nano-to micrometers and can be formed as monolithic or coaxial produced by a reliable and up-scalable approach.…”