Nano-adjuvant based on silk fibroin for the delivery of recombinant hepatitis B surface antigen

Polydopamine-based nano adjuvant as a promising vaccine carrier induces significant immune responses against Acinetobacter baumannii-associated pneumonia

The objective of this study was to assess the effectiveness of polydopamine nanoparticles (PDANPs) as a delivery system for intranasal antigen administration to prevent Acinetobacter baumannii (A. baumannii)-associated pneumonia. In the in vitro phase, the conserved outer membrane protein 22 (Omp22)-encoding gene of A. baumannii was cloned, expressed, and purified, resulting in the production of recombinant Omp22 (rOmp22), which was verified using western blot. PDANPs were synthesized using dopamine monomers and loaded with rOmp22 through physical adsorption. The rOmp22-loaded PDANPs were characterized in terms of size, size distribution, zeta potential, field emission scanning electron microscopy (FESEM), loading capacity, Fourier transform infrared spectroscopy (FTIR), release profile, and cytotoxicity. In the in vivo phase, the adjuvant effect of rOmp22-loaded PDANPs was evaluated in terms of eliciting immune responses, including humoral and cytokine levels (IL-4, IL-17, and IFN-γ), as well as protection challenge. The rOmp22-loaded PDANPs were spherical with a size of 205 nm, a zeta potential of -14 mV, and a loading capacity of approximately 35.7 %. The released rOmp22 from nontoxic rOmp22-loaded PDANPs over 20 days was approximately 41.5 %, with preserved rOmp22 integrity. The IgG2a/IgG1 ratio and IFN-γ levels were significantly higher in immunized mice with rOmp22-loaded-PDANPs than in rOmp22-alum, naive Omp22, and control groups. Furthermore, rOmp22-loaded PDANPs induced effective protection against infection in the experimental challenge and showed more normal structures in the lung histopathology assay. The results of this study suggest the potential of PDANPs as a nano-adjuvant for inducing strong immune responses to combat A. baumannii.

Novel therapeutic approaches for the management of hepatitis infections

Hepatitis B virus (HBV) & hepatitis C virus (HCV) infection is a substantial reason for morbidity and mortality around the world. Chronic hepatitis B (CHB) infection is connected with an enhanced risk of liver cirrhosis, liver decompensation and hepatocellular carcinoma (HCC). Conventional therapy do face certain challenges, for example, poor tolerability and the growth of active resistance. Thus, novel treatment procedures are essential to accomplish the initiation of strong and stable antiviral immune reactions of the individuals. This review explores the current nanotechnology-based carriers for drug and vaccine delivery to treat HBV and HCV.

Design and fabrication of a vaccine candidate based on rOmpA from Klebsiella pneumoniae encapsulated in silk fibroin-sodium alginate nanoparticles against pneumonia infection

The present study describes the design and fabrication of a novel vaccine candidate based on the outer membrane protein A (rOmpA) from Klebsiella pneumoniae (K. pneumoniae) encapsulated in silk fibroin-sodium alginate nanoparticles (SF-SANPs) against K. pneumoniae-mediated pneumonia. The physicochemical properties, toxicity, release profile, and in vivo potency of SF-SANPs encapsulated with rOmpA were evaluated. The spherical nano vaccine was created with an average particle size of 160 nm and an encapsulation efficiency of 80 %. Antigen release from SF-SANPs was 40 % after 22 days release assay. The SF-SANPs showed a zeta potential of -24.8 mV and had no toxic effect on the L929 cells in vitro. It was found that SF-SANPs in the vaccine formulation promoted systemic and mucosal antibodies and also stimulated cytokine responses, inducing both humoral (Th2) and cellular (Th1) immune responses, with a Th1-polarized response. The vaccine candidate was effective in protecting the mice lung against experimental pneumonia and reducing inflammation. These findings suggest that the rOmpA-based vaccine encapsulated in SF-SANPs could be a promising strategy for preventing pneumonia caused by K. pneumoniae.

Immunogenic Potential and Therapeutic Efficacy of Multi-Epitope Encapsulated Silk Fibroin Nanoparticles against Pseudomonas aeruginosa-Mediated Urinary Tract Infections

Pseudomonas aeruginosa (P. aeruginosa) causing urinary tract infections (UTIs) are a major concern among hospital-acquired infections. The need for an effective vaccine that reduces the infections is imperative. This study aims to evaluate the efficacy of a multi-epitope vaccine encapsulated in silk fibroin nanoparticles (SFNPs) against P. aeruginosa-mediated UTIs. A multi-epitope is constructed from nine proteins of P. aeruginosa using immunoinformatic analysis, expressed, and purified in BL21 (DE3) cells. The encapsulation efficiency of the multi-epitope in SFNPs is 85% with a mean particle size of 130 nm and 24% of the encapsulated antigen is released after 35 days. The vaccine formulations adjuvanted with SFNPs or alum significantly improve systemic and mucosal humoral responses and the cytokine profile (IFN-γ, IL-4, and IL-17) in mice. Additionally, the longevity of the IgG response is maintained for at least 110 days in a steady state. In a bladder challenge, mice treated with the multi-epitope admixed with alum or encapsulated in SFNPs demonstrate significant protection of the bladder and kidneys against P. aeruginosa. This study highlights the promising therapeutic potential of a multi-epitope vaccine encapsulated in SFNPs or adjuvanted with alum against P. aeruginosa infections.

Silk Nanocarrier Size Optimization for Enhanced Tumor Cell Penetration and Cytotoxicity In Vitro

Silk nanofibers are versatile carriers for hydrophobic and hydrophilic drugs, but fall short in terms of effective delivery to cells, which is essential for therapeutic benefits. Here, the size of silk nanofibers was tuned by ultrasonic treatment to improve the cell penetration features without impacting the structural features. The gradual decrease in silk nanofiber length from 1700 to 40 nm resulted in improved cell uptake. The internalized silk nanofiber carriers evaded lysosomes, which facilitated retention in cancer cells in vitro. The smaller sizes also facilitated enhanced penetration of tumor spheroids for improved delivery in vitro. The cytotoxicity of paclitaxel (PTX)-laden nanocarriers increased when the length of the silk nanocarriers decreased. Both the drug loading capacity and delivery of silk nanocarriers with optimized sizes suggest potential utility in cell treatments.