Exogenous pulmonary surfactant: A review focused on adjunctive therapy for severe acute respiratory syndrome coronavirus 2 including SP-A and SP-D as added clinical marker.

Type I and type II pneumocytes are two forms of epithelial cells found lining the alveoli in the lungs. Type II pneumocytes exclusively secrete 'pulmonary surfactants,' a lipoprotein complex made up of 90% lipids (mainly phospholipids) and 10% surfactant proteins (SP-A, SP-B, SP-C, and SP-D). Respiratory diseases such as influenza, severe acute respiratory syndrome coronavirus infection, and severe acute respiratory syndrome coronavirus 2 infection are reported to preferentially attack type II pneumocytes of the lungs. After viral invasion, consequent viral propagation and destruction of type II pneumocytes causes altered surfactant production, resulting in dyspnea and acute respiratory distress syndrome in patients with coronavirus disease 2019. Exogenous animal-derived or synthetic pulmonary surfactant therapy has already shown immense success in the treatment of neonatal respiratory distress syndrome and has the potential to contribute efficiently toward repair of damaged alveoli and preventing severe acute respiratory syndrome coronavirus 2-associated respiratory failure. Furthermore, early detection of surfactant collectins (SP-A and SP-D) in the circulatory system can be a significant clinical marker for disease prognosis in the near future.

Nanotechnology in Plants.

The integration of nanotechnology in medicine has had a tremendous impact in the past few decades. The discovery of synthesis of nanomaterials (NMs) and their functions as versatile tools promoted various applications in nano-biotechnology and nanomedicine. Although the physical and chemical methods are still considered as commonly used methods, they introduce several drawbacks such as the use of toxic chemicals (solvent, reducing, and capping agents) and poor control of size, size distribution, and morphology, respectively. Additionally, the NMs synthesized in organic solvents and hydrophobic surfactants rapidly aggregate in aqueous solutions or under physiologic conditions, limiting their applications in medicine. Many of the phase-transfer strategies were developed and applied for the transfer of NMs into aqueous solutions. Although great efforts have been put into phase transfers, they mostly include expensive, time-consuming, intensive labor work, multi steps, and complicated procedures.Use of plant extracts in the biological synthesis method offers stark advantages over other biomolecules (protein, enzyme, peptide, and DNA). Plant extracts have been commonly used for food, medicine, NM synthesis, and biosensing. There are many viable techniques developed for the production of plant extracts with various contents based on their simplicity, cost, and the type of extract content. In this chapter, we conduct a comparative study for extract preparation techniques, the use of extracts for metallic single and hybrid nanoparticle (NP) synthesis, and their antimicrobial properties against pathogenic and plant-based bacteria. Graphical Abstract.

Formation of functional nanobiocatalysts with a novel and encouraging immobilization approach and their versatile bioanalytical applications.

The discovery of functional organic-inorganic hybrid nanoflowers (FNFs) consisting of proteins/enzymes as the organic components and Cu(ii) ion as the inorganic component has made an enormous impact on enzyme immobilization studies. The FNFs synthesized by an encouraging and novel approach not only showed high stabilities but also much enhanced catalytic activities as compared to free and conventionally immobilized enzymes. A recent development demonstrated that FNF formation has moved beyond the initial discovery in which enzymes and Cu2+ ions used as the organic and inorganic parts, respectively, are replaced with new organic (chitosan, amino acid and plant extracts) and inorganic (Cu2+ and Fe2+) materials. The new organic materials incorporated into FNFs act as Fenton-like agents and then show peroxidase-like activity owing to the metal ions and the porous structure of FNFs in the presence of hydrogen peroxide (H2O2). All FNFs have been widely utilized in many different scientific and industrial fields due to their greatly enhanced activities and stabilities. This review focuses primarily on the preparation, characterization, and bioanalytical applications of FNFs and explains the mechanisms of their formation and enhanced activities and stabilities.