Ultrasound mediates the release of curcumin from microemulsions

Ultrasound is a powerful noninvasive modality for biomedical imaging, and holds much promise for noninvasive drug delivery enhancement and targeting. However, the optimal design of sound sensitive carriers is still poorly understood. In this study, curcumin, an important natural antioxidant and anticancer compound, was stably entrapped into microemulsion droplets with average size 20-35 nm. To release curcumin, low frequency (40 kHz) ultrasound at an intensity of 3.8 or 9.8 W/cm2 was applied to the microemulsions, using a probe sonicator. On insonation, much of the curcumin was released from the microemulsions and formed insoluble aggregates, as evidenced by decreased UV-vis absorption at 420 nm. The initial release rate (assayed by the rate of change of absorption) was as high as 0.11 microg/s (1.87%/sec) in phosphate buffered saline solution at neutral pH, but decreased at acidic pH. Interestingly, lower curcumin loading led to a more rapid release under insonation. Measurements of emulsion droplet size implicate droplet reorganization (fusion or fission) as an important contributing mechanism for the ultrasonic release of this compound. Although cargo in microemulsions is partitioned, rather than encapsulated (as in, for example, liposomes), these new results demonstrate that microemulsion carriers are feasible for some ultrasonic drug delivery applications.     

Polymers imprinted with three REG1B peptides for electrochemical determination of Regenerating Protein 1B,a urinary biomarker for pancreatic ductal adenocarcinoma

Microchimica Acta - Three peptides (each containing 13–18 amino acids) were synthesized and used as templates for molecular imprinting and epitope recognition of the Regenerating Protein 1B...     

Optical recognition of salivary proteins by use of molecularly imprinted poly(ethylene-co-vinyl alcohol)/quantum dot composite nanoparticles

Molecularly imprinted polymers (MIPs) have long been studied for applications in biomolecule recognition and binding; compared with natural antibodies, they may offer advantages in cost and stability. We report on the development of MIPs that “self-report” concentrations of bound analytes via fluorescence changes in embedded quantum dots (QDots). Composite QDot/MIPs were prepared using phase inversion of poly(ethylene-co-vinyl alcohol) (EVAL) solutions with various ethylene mole ratios in the presence of salivary target molecules (e.g. amylase, lipase, and lysozyme). These major protein components of saliva have been implicated as possible biomarkers for pancreatic cancer. The optimum (highest imprinting effectiveness) ethylene mole ratios of the commercially available EVALs were found to be 32, 38, and 44 mol% for the imprinting of amylase, lipase, and lysozyme, respectively. QD fluorescence quenching was observed on binding of analytes to composite MIPs in a concentration-dependent manner, and was used to construct calibration curves. Finally, the composite MIP particles were used for the quantitative detection of amylase, lipase, and lysozyme in real samples (saliva) and compared with a commercial Architect ci 8200 chemical analysis system.     

The complete replacement of antibodies by protein-imprinted poly(ethylene-co-vinyl alcohol) in sandwich fluoroimmunoassays

The replacement of antibodies by molecularly imprinted polymers (MIPs) has been investigated for many decades. However, indirect protocols (including natural primary and secondary antibodies) are still utilized to evaluate the ability of MIP thin films to recognize target molecules. MIPs can be prepared as either a thin film or as particles, and cavities that are complementary to the template can be generated on their surfaces. We have prepared thin film MIPs and particle MIPs prepared by solvent evaporation and phase inversion, respectively, from solutions of poly(ethylene-co-vinyl alcohol) (pEVAL) in the presence of the target analytes amylase, lysozyme, and lipase. These were first adsorbed on MIP thin films and by MIP particles that contain fluorescent quantum dots. Sandwich fluoroimmunoassays were then conducted to quantify them in MIP-coated 96-well microplates. The method was applied to determine amylase in saliva, and results were compared with a commercial analytical system.

     

The complete replacement of antibodies by protein-imprinted poly(ethylene-co-vinyl alcohol) in sandwich fluoroimmunoassays

The replacement of antibodies by molecularly imprinted polymers (MIPs) has been investigated for many decades. However, indirect protocols (including natural primary and secondary antibodies) are still utilized to evaluate the ability of MIP thin films to recognize target molecules. MIPs can be prepared as either a thin film or as particles, and cavities that are complementary to the template can be generated on their surfaces. We have prepared thin film MIPs and particle MIPs prepared by solvent evaporation and phase inversion, respectively, from solutions of poly(ethylene-co-vinyl alcohol) (pEVAL) in the presence of the target analytes amylase, lysozyme, and lipase. These were first adsorbed on MIP thin films and by MIP particles that contain fluorescent quantum dots. Sandwich fluoroimmunoassays were then conducted to quantify them in MIP-coated 96-well microplates. The method was applied to determine amylase in saliva, and results were compared with a commercial analytical system.