Characterization of Bovine Serum Albumin and (-)-Epigallocatechin Gallate/3,4- O-Dicaffeoylquinic Acid/Tannic Acid Layer by Layer Assembled Microcapsule for Protecting Immunoglobulin G in Stomach Digestion and Release in Small Intestinal Tract

Protein-based layer-by-layer films for biomedical applications

The surface engineering of biomaterials is crucial for their successful (bio)integration by the body, i.e. the colonization by the tissue-specific cell, and the prevention of fibrosis and/or bacterial colonization. Performed at room temperature in an aqueous medium, the layer-by-layer (LbL) coating method is based on the alternating deposition of macromolecules. Versatile and simple, this method allows the functionalization of surfaces with proteins, which play a crucial role in several biological mechanisms. Possessing intrinsic properties (cell adhesion, antibacterial, degradable, etc.), protein-based LbL films represent a powerful tool to control bacterial and mammalian cell fate. In this article, after a general introduction to the LbL technique, we will focus on protein-based LbL films addressing different biomedical issues/domains, such as bacterial infection, blood contacting surfaces, mammalian cell adhesion, drug and gene delivery, and bone and neural tissue engineering. We do not consider biosensing applications or electrochemical aspects using specific proteins such as enzymes.

The mechanism of epigallocatechin-3-gallate inhibiting the antigenicity of β-lactoglobulin under pH 6.2, 7.4 and 8.2: Multi-spectroscopy and molecular simulation methods

The antigenicity of β-lactoglobulin (β-LG) can be influenced by pH values and reduced by epigallocatechin-3-gallate (EGCG). However, a detailed mechanism concerning EGCG decreasing the antigenicity of β-LG at different pH levels lacks clarity. Here, we explore the inhibition mechanism of EGCG on the antigenicity of β-LG at pH 6.2, 7.4 and 8.2 using enzyme-linked immunosorbent assay, multi-spectroscopy, mass spectrometry and molecular simulations. The results of Fourier transform infrared spectroscopy (FTIR) and circular dichroism (CD) elucidate that the noncovalent binding of EGCG with β-LG induces variations in the secondary structure and conformations of β-LG. Moreover, EGCG inhibits the antigenicity of β-LG the most at pH 7.4 (98.30 %), followed by pH 6.2 (73.18 %) and pH 8.2 (36.24 %). The inhibitory difference is attributed to the disparity in the number of epitopes involved in the interacting regions of EGCG and β-LG. Our findings suggest that manipulating pH conditions may enhance the effectiveness of antigenic inhibitors, with the potential for further application in the food industry.

Microencapsulation as a Protective Strategy for Sialylated Immunoglobulin G: Efficacy in Alleviating Symptoms of Dextran Sulfate Sodium-Induced Colitis in Mice and Potential Mechanisms

Sialylated immunoglobulin G (IgG) is a vital glycoprotein in breast milk with the ability to promote the growth of Bifidobacterium in gut microbiota and relieve inflammatory bowel disease (IBD) symptoms in vitro. Here, it was found that the microcapsules with sialylated IgG could protect and release sialylated IgG with its structure and function in the intestine. Furthermore, the sialylated IgG microcapsules alleviated the clinical symptoms (body weight, feed quantity, and colon length loss), decreased disease activity index score, suppressed the production of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, IFN-γ, and MCP-1) and endotoxin (lipopolysaccharide), and enhanced the intestinal mucosal barrier (Claudin1, Muc2, Occludin, and ZO-1) in dextran sulfate sodium (DSS)-induced colitis mice. Additionally, the sialylated IgG microcapsules improved the gut microbiota by increasing the relative abundance of critical microbe Bifidobacterium bifidum and promoted the production of short-chain fatty acids (SCFAs). Correlation analysis indicated that the key microbes were strongly correlated with pro-inflammatory factors, clinical symptoms, tight junction protein, and SCFAs. These findings suggest that the sialylated IgG microcapsules have the potential to be used as a novel therapeutic approach for treating IBD.

Ultrasound-assisted multilayer Pickering emulsion fabricated by WPI-EGCG covalent conjugates for encapsulating probiotics in colon-targeted release

This study demonstrated the influences of ultrasound-assisted multilayer Pickering double emulsion capsules on the pasteurization and gastrointestinal digestive viability of probiotic (L. plantarum) strain liquid. Firstly, the role of ultrasonic homogenization on the morphology of W₁/O/W₂ double emulsions were studied. The double emulsion formed by ultrasonic intensity at 285 W had a single and narrow distribution with smallest droplet size. The double emulsion particles were then coated with chitosan(Chi), alginate (Alg), and CaCl₂(Ca). The multilayer emulsion after pasteurization and gastrointestinal digestion both had the highest viability at 5 coating layers, but its particle size (108.65 μm) exceeded the limit of human oral sensory (80 μm). It could be noted that the deposition of 3-4 layers of coating had similar activity after pasteurization/GIT digestion. And droplets with 3 layers of coating were the minimum and most available formulation for encapsulated probiotics (L. plantarum). Hence, the results suggest that the use of ultrasound-assisted multilayer emulsions encapsulated with probiotics in granular food and pharmaceutical applications is a promising strategy.

Degradation of Hybrid Drug Delivery Carriers with a Mineral Core and a Protein–Tannin Shell under Proteolytic Hydrolases

Hybrid carriers with the mineral CaCO₃/Fe₃O₄ core and the protein–tannin shell are attractive for drug delivery applications due to reliable coupling of anticancer drugs with protein–tannin complex and the possibility of remote control over drug localization and delivery by the external magnetic field. This study aims to elucidate the mechanisms of drug release via enzymatic degradation of a protein–tannin carrier shell triggered by proteolytic hydrolases trypsin and pepsin under physiological conditions. To do this, the carriers were incubated with the enzyme solutions in special buffers to maintain the enzyme activity. The time-lapse spectrophotometric and electron microscopy measurements were carried out to evaluate the degradation of the carriers. It was established that the protein–tannin complex demonstrates the different degradation behavior depending on the enzyme type and buffer medium. The incubation in trypsin solution mostly resulted in the protein shell degradation. The incubation in pepsin solution did not affect the protein component; however, the citric buffer stimulates the degradation of the mineral core. The presented results allow for predicting the degradation pathways of the carriers including the release profile of the loaded cargo under physiological conditions. The viability of 4T1 breast cancer cells with mineral magnetic carriers with protein–tannin shells was investigated, and their movement in the fields of action of the permanent magnet was shown.

Towards the systematic design of multilayer O/W emulsions with tannic acid as an interfacial antioxidant

This work discusses the possibility of designing multilayer oil-in-water emulsions to introduce the maximum possible amount of an antioxidant at the droplet interfaces for the optimal protection of a linseed oil core against oxidation, using a systematic three-step colloidal procedure. An antioxidant (here Tannic Acid - TA) is chosen and its interactions with a primary emulsifier (here Bovine Serum Albumin - BSA) and several polysaccharides are first examined in solution using turbidity measurements. As a second step, LbL deposition on solid surfaces is used to determine which of the polysaccharides to combine with BSA and tannic acid in a multilayer system to ensure maximum presence of tannic acid in the films. From UV-vis and polarization modulation infrared reflection-absorption (PM-IRRAS) spectroscopic measurements it is suggested that the best components to use in a multilayer emulsion droplet, together with BSA and TA, are chitosan and pectin. BSA, chitosan and pectin are subsequently used for the formation of three-layer linseed oil emulsions, and tannic acid is introduced into any of the three layers as an antioxidant. The effect of the exact placement of tannic acid on the oxidative stabilization of linseed oil is assessed by monitoring the fluorescence of Nile red, dissolved in the oil droplets, under the attack of radicals generated in the aqueous phase of the emulsion. From the results it appears that the three-stage procedure presented here can serve to identify successful combinations of interfacial components of multilayer emulsions. It is also concluded that the exact interfacial placement of the antioxidant plays an important role in the oxidative stabilization of the valuable oil core.

Commensal Relationship of Three Bifidobacterial Species Leads to Increase of Bifidobacterium in Vitro Fermentation of Sialylated Immunoglobulin G by Human Gut Microbiota

Sialylated immunoglobulin G (IgG) is an important immunoglobulin in breast milk, but its effect on adult gut microbiota is not yet clear due to digestion by pepsin. Based on our previous IgG protecting study, effects of sialylated IgG on gut microbiota were investigated by in vitro anaerobic fermentation in the present study. It was found that the addition of sialylated IgG could significantly promote the growth of Bifidobacterium. Meanwhile, three bifidobacterial species B. bifidum CCX 19061, Bembidion breve CCX 19041, and B. longum subsp. infantis CCX 19042 were isolated. Furthermore, B. breve CCX 19041 and B. longum subsp. infantis CCX 19042 showed co-culture growth property with B. bifidum CCX 19061 in a sialylated IgG-based medium, which was also supported by changes of free monosaccharides and N-glycan structure. These findings suggest that the increase of Bifidobacterium in vitro fermentation is attributed to the commensal relationship of the three bifidobacterial species by utilizing sugars released from sialylated IgG.

A poly(allylamine hydrochloride)/poly(styrene sulfonate) microcapsule-coated cotton fabric for stimulus-responsive textiles

This study reports the design of a stimulus-responsive fabric incorporating a combination of microcapsules, containing polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) sodium salt (PSS), formed via a layer-by-layer (LBL) approach. The use of PAH and PSS ensured that the microcapsule structure was robust and pH-sensitive. SEM and TEM studies showed that the composite microcapsule (PAH/PSS) n PAH had a spherical morphology with a hollow structure. FTIR demonstrated the presence of PAH and PSS, confirming the composition of the microcapsule shell. DSC showed that the microcapsules were thermally stable. The size of the microcapsules ranged from 4 μm to 6 μm. The hollow microcapsules can be used as a carrier for loading and releasing chemicals under different pH conditions. The release rate of Rhodamine-B from (PAH/PSS) n PAH microcapsules was higher at pH 5.8 than that at 7.4, confirming the pH sensitivity. The hollow structure of (PAH/PSS) n PAH microcapsules is expected to act as a carrier and medium to introduce functional chemicals into the fabric with long-lasting property and pH stimulus responsivity. Furthermore, a positively charged compound with ethylene oxide groups was added during the coating process as a crosslinker binding (PAH/PSS)2PAH for the microcapsules with the cotton fabric more efficiently. Using this method, numerous substances, e.g., drugs, dyes, natural herbs, or perfumes, could be stored into the LBL microcapsules for a relatively long time, constantly releasing them from the coated textiles. Since LBL microcapsules were easy to combine with fabrics, this study provided a feasible approach for the preparation of functional stimulus-responsive textiles.