Stimuli-responsive and biomimetic delivery systems for sepsis and related complications

Multi-functional pH-responsive and biomimetic chitosan-based nanoplexes for targeted delivery of ciprofloxacin against bacterial sepsis

Bacterial sepsis is a mortal syndromic disease characterized by a complex pathophysiology that hinders effective targeted therapy. This study aimed to develop multifunctional, biomimetic and pH-responsive ciprofloxacin-loaded chitosan (CS)/sodium deoxycholic acid (SDC) nanoplexes (CS/SDC) nanoplexes with the ability to target and modulate the TLR4 pathway, activated during sepsis. The formulated nanoplexes were characterized in terms of physicochemical properties, in silico and in vitro potential biological activities. The optimal formulation showed good biocompatibility and stability with appropriate physicochemical parameters. The surface charge changed from negative at pH 7.4 to positive at pH 6.0 accompanied with a significantly faster release of CIP at pH 6.0 compared to 7.4. The biomimicry was elucidated by in silico tools and MST and results confirmed strong binding between the system and TLR4. Furthermore, the system revealed 4- and 2-fold antibacterial enhancement at acidic pH, and 3- and 4-fold better antibiofilm efficacy against Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (P. aeruginosa) respectively, compared to bare CIP. In addition, enhanced bacterial efflux pump inhibition was demonstrated by CS/SDC nanoplexes. Finally, the developed nanosystem showed excellent antioxidant activity against DPPH radicals. Taken together, the study confirmed the multi-functionalities of CS/SDC nanoplexes and their potential benefits in improving bacterial sepsis therapy.

Robust and Multifunctional Therapeutic Nanoparticles against Peritonitis-Induced Sepsis

Apart from bacterial growth and endotoxin generation, the excessive production of reactive radicals linked with sepsis also has a substantial impact on triggering an inflammatory response and further treatment failure. Hence, the rational design and fabrication of robust and multifunctional nanoparticles (NPs) present a viable means of overcoming this dilemma. In this study, we used antibiotic polymyxin B (PMB) and antioxidant natural polyphenolic protocatechualdehyde (PCA) to construct robust and multifunctional NPs for sepsis treatment, leveraging the rich chemistries of PCA. The PMB release profile from the NPs demonstrated pH-responsive behavior, which allowed the NPs to exhibit effective bacterial killing and radical scavenging properties. Data from in vitro cells stimulated with H2O2 and lipopolysaccharide (LPS) showed the multifunctionalities of NPs, including intracellular reactive oxygen species (ROS) scavenging, elimination of the bacterial toxin LPS, inhibiting macrophage M1 polarization, and anti-inflammation capabilities. Additionally, in vivo studies further demonstrated that NPs could increase the effectiveness of sepsis treatment by lowering the bacterial survival ratio, the expression of the oxidative marker malondialdehyde (MDA), and the expression of inflammatory cytokine TNF-α. Overall, this work provides ideas of using those robust and multifunctional therapeutic NPs toward enhanced sepsis therapy efficiency.

Bioengineered nanotechnology for nucleic acid delivery

Nucleic acid-based therapy has emerged as a promising therapeutic approach for treating various diseases, such as genetic disorders, cancers, and viral infections. Diverse nucleic acid delivery systems have been reported, and some, including lipid nanoparticles, have exhibited clinical success. In parallel, bioengineered nucleic acid delivery nanocarriers have also gained significant attention due to their flexible functional design and excellent biocompatibility. In this review, we summarize recent advances in bioengineered nucleic acid delivery nanocarriers, focusing on exosomes, cell membrane-derived nanovesicles, protein nanocages, and virus-like particles. We highlight their unique features, advantages for nucleic acid delivery, and biomedical applications. Furthermore, we discuss the challenges that bioengineered nanocarriers face towards clinical translation and the possible avenues for their further development. This review ultimately underlines the potential of bioengineered nanotechnology for the advancement of nucleic acid therapy.

A Cyclodextrin-Based pH-Responsive MicroRNA Delivery Platform Targeting Polarization of M1 to M2 Macrophages for Sepsis Therapy

The mortality rate of sepsis remains high despite improvements in the diagnosis and treatment of sepsis using symptomatic and supportive therapies, such as anti-infection therapy and fluid resuscitation. Nucleic acid-based drugs have therapeutic potential, although their poor stability and low delivery efficiency have hindered their widespread use. Herein, it is confirmed that miR-223 can polarize proinflammation M1 macrophages to anti-inflammation M2 macrophages. A pH-sensitive nano-drug delivery system comprising β-cyclodextrin-poly(2-(diisopropylamino)ethyl methacrylate)/distearoyl phosphoethanolamine-polyethylene glycol (β-CD-PDPA/DSPE-PEG) is synthesized and developed to target M1 macrophages and miR-223 is encapsulated into nanoparticles (NPs) for sepsis treatment. NPs/miR-223 demonstrated in vitro pH responsiveness with favorable biosafety, stability, and high delivery efficiency. In vivo studies demonstrate that NPs/miR-223 are preferentially accumulated and retained in the inflammation site, thereby reducing inflammation and improving the survival rate of mice with sepsis while exhibiting ideal biosafety. Mechanically, NPs/miR-223 regulates macrophage polarization by targeting Pknox1 and inhibiting the activation of the NF-κB signaling pathway, thereby achieving an anti-inflammatory effect. Collectively, it is demonstrated that the miRNA delivery vector described here provides a new approach for sepsis treatment and accelerates the advancement of nucleic acid drug therapy.

Inflammation-responsive drug delivery nanosystems for treatment of bacterial-induced sepsis

Sepsis, a complication of dysregulated host immune systemic response to an infection, is life threatening and causes multiple organ injuries. Sepsis is recognized by WHO as a big contributor to global morbidity and mortality. The heterogeneity in sepsis pathophysiology, antimicrobial resistance threat, the slowdown in the development of antimicrobials, and limitations of conventional dosage forms jeopardize the treatment of sepsis. Drug delivery nanosystems are promising tools to overcome some of these challenges. Among the drug delivery nanosystems, inflammation-responsive nanosystems have attracted considerable interest in sepsis treatment due to their ability to respond to specific stimuli in the sepsis microenvironment to release their payload in a precise, targeted, controlled, and rapid manner compared to non-responsive nanosystems. These nanosystems posit superior therapeutic potential to enhance sepsis treatment. This review critically evaluates the recent advances in the design of drug delivery nanosystems that are inflammation responsive and their potential in enhancing sepsis treatment. The sepsis microenvironment's unique features, such as acidic pH, upregulated receptors, overexpressed enzymes, and enhanced oxidative stress, that form the basis for their design have been adequately discussed. These inflammation-responsive nanosystems have been organized into five classes namely: Receptor-targeted nanosystems, pH-responsive nanosystems, redox-responsive nanosystems, enzyme-responsive nanosystems, and multi-responsive nanosystems. Studies under each class have been thematically grouped and discussed with an emphasis on the polymers used in their design, nanocarriers, key characterization, loaded actives, and key findings on drug release and therapeutic efficacy. Further, this information is concisely summarized into tables and supplemented by inserted figures. Additionally, this review adeptly points out the strengths and limitations of the studies and identifies research avenues that need to be explored. Finally, the challenges and future perspectives on these nanosystems have been thoughtfully highlighted.

Self-Propelled Proteomotors with Active Cell-Free mtDNA Clearance for Enhanced Therapy of Sepsis-Associated Acute Lung Injury

Acute lung injury (ALI) is a frequent and serious complication of sepsis with limited therapeutic options. Gaining insights into the inflammatory dysregulation that causes sepsis-associated ALI can help develop new therapeutic strategies. Herein, the crucial role of cell-free mitochondrial DNA (cf-mtDNA) in the regulation of alveolar macrophage activation during sepsis-associated ALI is identified. Most importantly, a biocompatible hybrid protein nanomotor (NM) composed of recombinant deoxyribonuclease I (DNase-I) and human serum albumin (HSA) via glutaraldehyde-mediated crosslinking is prepared to obtain an inhalable nanotherapeutic platform targeting pulmonary cf-mtDNA clearance. The synthesized DNase-I/HSA NMs are endowed with self-propulsive capability and demonstrate superior performances in stability, DNA hydrolysis, and biosafety. Pulmonary delivery of DNase-I/HSA NMs effectively eliminates cf-mtDNAs in the lungs, and also improves sepsis survival by attenuating pulmonary inflammation and lung injury. Therefore, pulmonary cf-mtDNA clearance strategy using DNase-I/HSA NMs is considered to be an attractive approach for sepsis-associated ALI.

Membrane-camouflaged biomimetic nanoparticles as potential immunomodulatory solutions for sepsis: An overview

Sepsis is a life-threatening organ dysfunction due to dysregulated host responses induced by infection. The presence of immune disturbance is key to the onset and development of sepsis but has remarkably limited therapeutic options. Advances in biomedical nanotechnology have provided innovative approaches to rebalancing the host immunity. In particular, the technique of membrane-coating has demonstrated remarkable improvements to therapeutic nanoparticles (NPs) in terms of tolerance and stability while also improving their biomimetic performance for immunomodulatory purposes. This development has led to the emergence of using cell-membrane-based biomimetic NPs in treating sepsis-associated immunologic derangements. In this minireview, we present an overview of the recent advances in membrane-camouflaged biomimetic NPs, highlighting their multifaceted immunomodulatory effects in sepsis such as anti-infection, vaccination, inflammation control, reversing of immunosuppression, and targeted delivery of immunomodulatory agents.