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Nano-stereocomplexation of polylactide (PLA) spheres by spray droplet atomization.

ABSTRACT: A direct, efficient, and scalable method to prepare stereocomplexed polylactide (PLA)-based nanoparticles (NPs) is achieved. By an appropriate combination of fabrication parameters, NPs with controlled shape and crystalline morphology are obtained and even pure PLA stereocomplexes (PLASC) are successfully prepared using the spray-drying technology. The formed particles of varying D- and L-LA content have an average size of ?400 nm, where the smallest size is obtained for PLA50, which has an equimolar composition of PLLA and PDLA in solution. Raman spectra of the particles show the typical shifts for PLASC in PLA50, and thermal analysis indicates the presence of pure stereocomplexation, with only one melting peak at 226 °C. Topographic images of the particles exhibit a single phase with different surface roughness in correlation with the thermal analysis. A high yield of spherically shaped particles is obtained. The results clearly provide a proficient method for achieving PLASC NPs that are expected to function as renewable materials in PLA-based nanocomposites and potentially as more stable drug delivery carriers.

SUBMITTER: Arias V

PROVIDER: S-EPMC4283727 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature

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Nano-stereocomplexation of polylactide (PLA) spheres by spray droplet atomization.

Arias Veluska V Odelius Karin K Albertsson Ann-Christine AC

Macromolecular rapid communications 20140929 22

A direct, efficient, and scalable method to prepare stereocomplexed polylactide (PLA)-based nanoparticles (NPs) is achieved. By an appropriate combination of fabrication parameters, NPs with controlled shape and crystalline morphology are obtained and even pure PLA stereocomplexes (PLASC) are successfully prepared using the spray-drying technology. The formed particles of varying D- and L-LA content have an average size of ≈400 nm, where the smallest size is obtained for PLA50, which has an equi ...[more]

PMID: 25262929

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Project description:Since the outbreak of COVID-19 pandemic, maintaining safety in dental operations has challenged health care providers and policy makers. Studies on dental aerosols often focus on bacterial viability or particle size measurements inside dental offices during and after dental procedures, which limits their conclusions to specific cases. Fundamental understanding on atomization mechanism and dynamics of dental aerosols are needed while assessing the risks. Most dental instruments feature a build-in atomizer. Dental aerosols that are produced by ultrasonic or rotary atomization are considered to pose the highest risks. In this work, we aimed to characterize dental aerosols produced by both methods, namely by Mectron PIEZOSURGERY® and KaVo EXPERTtorque™. Droplet size distributions and velocities were measured with a high-speed camera and a rail system. By fitting the data to probability density distributions and using empirical equations to predict droplet sizes, we were able to postulate the main factors that determine droplet sizes. Both dental instruments had wide size distributions including small droplets. Droplet size distribution changed based on operational parameters such as liquid flow rate or air pressure. With a larger fraction of small droplets, rotary atomization poses a higher risk. With the measured velocities reaching up to 5 m s-1, droplets can easily reach the dentist in a few seconds. Small droplets can evaporate completely before reaching the ground and can be suspended in the air for a long time. We suggest that relative humidity in dental offices are adjusted to 50% to prevent fast evaporation while maintaining comfort in the office. This can reduce the risk of disease transmission among patients. We recommend that dentists wear a face shield and N95/FFP2/KN95 masks instead of surgical masks. We believe that this work gives health-care professionals, policy makers and engineers who design dental instruments insights into a safer dental practice.

Dataset Information

Nano-stereocomplexation of polylactide (PLA) spheres by spray droplet atomization.

Publications

Nano-stereocomplexation of polylactide (PLA) spheres by spray droplet atomization.

Similar Datasets

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