Biomaterials engineering and biotechnology have advanced significantly towards probiotic encapsulation with encouraging results in assuring sufficient bioactivity. However, some major challenges remain to be addressed, and these include maintaining stability in different compartments of the gastrointestinal tract (GIT), favoring adhesion only at the site of action, and increasing residence times. An alternative to addressing such challenges is to manufacture encapsulates with stimuli-responsive polymers, such that controlled release is achievable by incorporating moieties that respond to chemical and physical stimuli present along the GIT. This review highlights, therefore, such emerging delivery matrices going from a comprehensive description of addressable stimuli in each GIT compartment to novel synthesis and functionalization techniques to currently employed materials used for probiotic’s encapsulation and achieving multi-modal delivery and multi-stimuli responses. Next, we explored the routes for encapsulates design to enhance their performance in terms of degradation kinetics, adsorption, and mucus and gut microbiome interactions. Finally, we present the clinical perspectives of implementing novel probiotics and the challenges to assure scalability and cost-effectiveness, prerequisites for an eventual niche market penetration.

Gelatin and chitosan nanoparticles have been widely used in pharmaceutical, biomedical, and nanofood applications due to their high biocompatibility and biodegradability. This study proposed a highly efficient synthesis method for type B gelatin and low-molecular-weight (LMW) chitosan nanoparticles. Gelatin nanoparticles (GNPs) were synthesized by the double desolvation method and the chitosan nanoparticles (CNPs) by the ionic gelation method. The sizes of the obtained CNPs and GNPs (373 ± 71 nm and 244 ± 67 nm, respectively) and zeta potential (+36.60 ± 3.25 mV and −13.42 ± 1.16 mV, respectively) were determined via dynamic light scattering. Morphology and size were verified utilizing SEM and TEM images. Finally, their biocompatibility was tested to assure their potential applicability as bioactive molecule carriers and cell-penetrating agents.

At the beginning of 2020, the pandemic caused by the SARS-CoV-2 virus led to the fast sequencing of its genome to facilitate molecular engineering strategies to control the pathogen’s spread. The spike (S) glycoprotein has been identified as the leading therapeutic agent due to its role in localizing the ACE2 receptor in the host’s pulmonary cell membrane, binding, and eventually infecting the cells. Due to the difficulty of delivering bioactive molecules to the intracellular space, we hypothesized that the S protein could serve as a source of membrane translocating peptides. AHB-1, AHB-2, and AHB-3 peptides were identified and analyzed on a membrane model of DPPC (dipalmitoylphosphatidylcholine) using molecular dynamics (MD) simulations. An umbrella sampling approach was used to quantify the energy barrier necessary to cross the boundary (13.2 to 34.9 kcal/mol), and a flat-bottom pulling helped to gain a deeper understanding of the membrane’s permeation dynamics. Our studies revealed that the novel peptide AHB-1 exhibited comparable penetration potential of already known potent cell-penetrating peptides (CPPs) such as TP2, Buforin II, and Frenatin 2.3s. Results were confirmed by in vitro analysis of the peptides conjugated to chitosan nanoparticles, demonstrating its ability to reach the cytosol and escape endosomes, while maintaining high biocompatibility levels according to standardized assays.

Nowadays, nanoparticles (NPs) are used to make safe and more effective biomedical technologies for applications in highly targeted therapeutics and drug-delivery vehicles. This helps avoid low cellular penetration and accumulation of the drug in intracellular endosomal compartments that are not of interest to a particular therapy. A way to enhance therapeutic efficiency is through nanoparticle loading systems. This study aims to develop low molecular weight (LMW) and high molecular weight (HMW) chitosan and type B gelatin NPs. To enhance cell penetration, the NPs were interfaced with the translocating peptide Buforin II. The obtained nanobioconjugates were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), confocal microscopy, and transmission electron microscopy (TEM). Their size and surface zeta potential were estimated via DLS (Zetasizer Nano). Furthermore, to visualize their endosomal escape, the NPs were marked with the fluorophore Rhodamine B and imaged with the aid of confocal microscopy. The FTIR results showed bands corresponding to the polymers and Buforin II after conjugation. The average NPs diameters were about 250 nm. The zeta potential of the chitosan NPs approached neutrality, which may be problematic due to low colloidal stability. The gelatin zeta potential of −7 mV was closer to the value required for colloidal stability, i.e., ±10 mV. SEM microscopy of LMW and HMW chitosan NPs showed a round-shape and oval morphology, respectively, while the gelatin NPs had a filamentous morphology. SEM also shows agglomerates of the NPs. TEM microscopy results confirmed the LMW chitosan NPs morphology and showed that their nominal size was 5–10 nm.

A large arsenal of nanoparticles (NPs) have been developed for several biomedical applications ranging from property enhancers of polymeric scaffolds, gene therapy strategies to drug delivery vehicles for highly targeted therapies. However, to improve therapeutic efficacy, cell penetration and drug leakage from intracellular endosomal compartments are, thus far, some of the most