Technology assessment of new biodegradable poly(R-3-hydroxybutyrate-co -1,4-butylene adipate) copolymers for drug delivery

Recent Biotechnological Applications of Polyhydroxyalkanoates (PHA) in the Biomedical Sector-A Review

Petroleum-derived plastics are materials of great importance for the contemporary lifestyle, and are widely used commercially because they are low cost, resistant, malleable, and weightless, in addition to their hydrophobic character. However, some factors that confer the qualities of these materials also cause problems, mainly environmental, associated with their use. The COVID-19 pandemic aggravated these impacts due to the high demand for personal protective equipment and the packaging sector. In this scenario, bioplastics are environmentally positive alternatives to these plastics due to their applicability in several areas ranging from packaging, to biomedicine, to agriculture. Polyhydroxyalkanoates (PHAs) are biodegradable biopolymers usually produced by microorganisms as an energy reserve. Their structural variability provides a wide range of applications, making them a viable option to replace polluting materials. PHAs can be applied in various biotechnology sectors, such as producing drug carriers and scaffolds for tissue engineering. This review aimed to survey works published in the last five years on the study and biotechnological application of PHAs in the biomedical sector, exploring the versatility and advantages of their use and helping to understand how to enhance their application.

Polyhydroxyalkanoates-Based Nanoparticles as Essential Oil Carriers

Plant-derived essential oils (EOs) represent a green alternative to conventional antimicrobial agents in food preservation. Due to their volatility and instability, their application is dependent on the development of efficient encapsulation strategies allowing their protection and release control. Encapsulation in Polyhydroxyalkanoate (PHA)-based nanoparticles (NPs) addresses this challenge, providing a biodegradable and biobased material whose delivery properties can be tuned by varying polymer composition. In this work, EO from Mexican oregano was efficiently encapsulated in Polyhydroxybutyrate (PHB) and Poly-3-hydroxybutyrate-co-hydroxyhexanoate (PHB-HHx)-based NPs by solvent evaporation technique achieving high encapsulation efficiency, (>60%) and loading capacity, (about 50%). The obtained NPs displayed a regular distribution with a size range of 150–210 nm. In vitro release studies in food simulant media were fitted with the Korsmeyer–Peppas model, indicating diffusion as the main factor controlling the release. The cumulative release was affected by the polymer composition, possibly related to the more amorphous nature of the copolymer, as confirmed by WAXS and DSC analyses. Both the EO-loaded nanosystems displayed antimicrobial activity against Micrococcus luteus, with PHB-HHx-based NPs being even more effective than the pure EO. The results open the way to the effective exploitation of the developed nanosystems in active packaging.

Characterization of Gemcitabine Loaded Polyhydroxybutyrate Coated Magnetic Nanoparticles for Targeted Drug Delivery

BACKGROUND

Targeted drug delivery is one of the recent hot topics in cancer therapy. Because of having a targeting potential under the magnetic field and a suitable surface for the attachment of different therapeutic moieties, magnetic nanoparticles are widely studied for their applications in medicine.

OBJECTIVE

Gemcitabine loaded polyhydroxybutyrate coated magnetic nanoparticles (Gem-PHB-MNPs) were synthesized and characterized for the treatment of breast cancer by the targeted drug delivery method.

METHODS

The characterization of nanoparticles was confirmed by FTIR, XPS, TEM, and spectrophotometric analyses. The cytotoxicities of drug-free nanoparticles and Gemcitabine loaded nanoparticles were determined with cell proliferation assay using SKBR-3 and MCF-7 breast cancer cell lines.

RESULTS

The release of Gemcitabine from PHB-MNPs indicated a pH-dependent pattern, which is a desirable release characteristic, since the pH of the tumor microenvironment and endosomal structures are acidic, while bloodstream and healthy-tissues are neutral. Drug-free PHB-MNPs were not cytotoxic to the SKBR-3 and MCF- 7 cells, whereas the Gemcitabine loaded PHB-MNPs was about two-fold as cytotoxic with respect to free Gemcitabine. In vitro targeting ability of PHB-MNPs was shown under the magnetic field.

CONCLUSION

Considering these facts, we may suggest that these nanoparticles can be a promising candidate for the development of a novel targeted drug delivery system for breast cancer.

Development of polymer composites and encapsulation technology for slow-release fertilizers

The fertilizer manufacturing faces an ongoing challenge to develop its products to raise the effectiveness of their application, mainly of nitrogenous fertilizers, as well as to reduce any probable adverse ecological effect. In general, chemical fertilizers are very necessary for agricultural lands to provide the essential nutrients for plant growth, which are lost and leached into the surrounding environment during irrigation, which then leads to unwanted side effects, such as crop failure or increased losses to the environment. To solve this problem of nutrients being wasted, the most effective way is to use slow or controlled-release fertilizers (S/CRFs). The current review provides an insight vision into the methods used to save agricultural fertilizers from being wasted due to irrigation. The functional materials or physical techniques are used to maintain a steady release of nutrients. Fertilizers are encapsulated with various compounds based on synthetic or natural polymers to be used as SRFs. In this review paper, a comprehensive survey is presented on SRFs as an effective method in dealing with the problem of fertilizer wastage during irrigation. This review discusses the technology and applications of the latest research findings in this field.