Polymer-based nanencapsulation for drug delivery applications

The development of micro and nanometric encapsulation and porous spheres and their potential applications in cell culture and tissue regeneration have been reviewed in an article published in the journal Polymers.

To study: Designing Natural Polymer-Based Capsules and Spheres for Biomedical Applications – A Review. Image Credit: DedMityay / Shutterstock.com

Disadvantages of traditional drug therapy

The drug or pharmacological agent is administered directly into the body by mouth, respiratory route, or injectable in traditional drug therapy. However, this approach has several drawbacks, including the loss of prescribed drugs on the way from the site of administration to the target site due to biological deterioration and increased risks of over- or under-drug.

Because of these flaws, a new approach is needed.

Classification of polymer-based biomedical cargo carriers.

Classification of polymer-based biomedical cargo carriers. © Sharma, K., et al. (2021).

Develop nanotechnology methods

The development of nano- and microcapsules requires considering their use for various biomedical purposes. Such functions may include sustained release of cargo to the affected site in the body, stimuli-sensitive cargo discharge, targeted delivery to the site of action, protections from the hostile body environment, and enhanced bioavailability. in the body.

The structural arrangements of the spherical APC carrier systems (SACS) and the method of cargo encapsulation are selected based on these biomedical parameters, which determine the final route / technique of capsule synthesis.

Function of core-shell materials

The physicochemical characteristics of the natural polymer, its applications and the required mechanism of action influence the choice of the core-shell material. Sustained Release Equations are made from natural polymeric shells and core materials that allow the sustained release of APC through various processes such as dispersion, erosion, osmotic pressure, and swelling.

Purely diffusion-controlled release from a capsule describes the mass transfer of cargo from the capsule to the release carrier, which is driven by their concentration gradient. However, natural polymer release capsules generally undergo a mixture of dissolution, inflammation and erosion procedures to discharge the cargo at the target location.

Structural configurations of core-shell particles and porous natural polymers / proteins.

Structural configurations of core-shell particles and porous natural polymers / proteins. © Sharma, K., et al. (2021).

Drug delivery system

The cargo or drug release processes can be triggered in response to an external stimulus such as changes in temperature and pH or the existence of digestive enzymes. Due to the sensitivity of certain components (including the amine group in chitosan) to a certain pH and high temperatures, pods based on ionic polysaccharides of chitosan, alginate, agar, carrageenan, cellulose, gaur and xanthan gum showed a reactive pH and temperature-discharge. Pectin and chondroitin sulfate are also pH sensitive and susceptible to enzymatic degradation. Various polypeptides, such as albumins, exhibit sensitive pH, temperature, and enzymatic cargo release.

Nano-encapsulation techniques

Depending on the type of implementation or the comfort of the design, the cargo is encapsulated in micro- or nano-capsules during the encapsulation in progress or the post-synthesis encapsulation. Ongoing encapsulation involves immersing the cargo in the appropriate precursor solutions before using any of the many capsule synthesis techniques.

Once absorbed into the body, the cargo comprising such hydrophilic drugs and probiotic bacterial species has been shown to degrade. Encapsulating them inside hydrophobic polymer-based shells, such as zein protease, helps protect them from biodegradation before they are released at the target site. Hydrophilic and hydrophobic drugs have been protected by composite capsule shells and organic cores.

Schematic diagram of the emulsion modeling approach.

Schematic diagram of the emulsion modeling approach. © Sharma, K., et al. (2021).

Advancement in the Encapsulation of Nanotechnology

Protein drug delivery vectors exhibit a number of advantages including higher biocompatibility and good stability, biodegradability and greater drug binding potential leading to good drug loading efficiency.

Protein-based processes, such as hydrogels, have been designed and evaluated for use in the treatment of cancer, nutritional therapy, diabetes, musculoskeletal diseases, neurological diseases, and stem cell treatments.

Schematic diagram of ultrasound-assisted emulsification-coacervation.

Schematic diagram of ultrasound-assisted emulsification-coacervation. © Sharma, K., et al. (2021).

Due to its simple and fast technique, ultrasound-assisted flocculation is also considered to be one of the best capsule synthesis approaches. Several studies have used the ultrasound method to create capsules with a liquid core.

Continue reading: Synthetic protein nanoparticles: an overview.


Sharma, K., et al. (2021) Designing Natural Polymer-Based Capsules and Spheres for Biomedical Applications – A Review. Polymers 2021, 13 (24), 4307. Available at: https://www.mdpi.com/2073-4360/13/24/4307

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