Tuning chitosan's chemical structure for enhanced biological functions.

Chitosan, an amino polysaccharide mostly derived from crustaceans, has been recently highlighted for its biological activities that depend on its molecular weight (MW), degree of deacetylation (DD), and acetylation pattern (AP). More importantly, for some advanced biomaterials, the homogeneity of the chitosan structure is an important factor in determining its biological activity. Here we review emerging enzymes and cell factories, respectively, for in vitro and in vivo preparation of chitosan oligosaccharides (COSs), focusing on advances in the analysis of the AP and structural modification of chitosan to tune its functions. By 'mapping' current knowledge on chitosan's in vitro and in vivo activity with its MW and AP, this work could pave the way for future studies in the field.

Chitin and chitosan derived from crustacean waste valorization streams can support food systems and the UN Sustainable Development Goals.

Crustacean waste, consisting of shells and other inedible fractions, represents an underutilized source of chitin. Here, we explore developments in the field of crustacean-waste-derived chitin and chitosan extraction and utilization, evaluating emerging food systems and biotechnological applications associated with this globally abundant waste stream. We consider how improving the efficiency and selectivity of chitin separation from wastes, redesigning its chemical structure to improve biotechnology-derived chitosan, converting it into value-added chemicals, and developing new applications for chitin (such as the fabrication of advanced nanomaterials used in fully biobased electric devices) can contribute towards the United Nations Sustainable Development Goals. Finally, we consider how gaps in the research could be filled and future opportunities could be developed to make optimal use of this important waste stream for food systems and beyond.

Microfluidic Brain-on-a-Chip: Perspectives for Mimicking Neural System Disorders.

Neurodegenerative diseases (NDDs) include more than 600 types of nervous system disorders in humans that impact tens of millions of people worldwide. Estimates by the World Health Organization (WHO) suggest NDDs will increase by nearly 50% by 2030. Hence, development of advanced models for research on NDDs is needed to explore new therapeutic strategies and explore the pathogenesis of these disorders. Different approaches have been deployed in order to investigate nervous system disorders, including two-and three-dimensional (2D and 3D) cell cultures and animal models. However, these models have limitations, such as lacking cellular tension, fluid shear stress, and compression analysis; thus, studying the biochemical effects of therapeutic molecules on the biophysiological interactions of cells, tissues, and organs is problematic. The microfluidic "organ-on-a-chip" is an inexpensive and rapid analytical technology to create an effective tool for manipulation, monitoring, and assessment of cells, and investigating drug discovery, which enables the culture of various cells in a small amount of fluid (10-9 to 10-18 L). Thus, these chips have the ability to overcome the mentioned restrictions of 2D and 3D cell cultures, as well as animal models. Stem cells (SCs), particularly neural stem cells (NSCs), induced pluripotent stem cells (iPSCs), and embryonic stem cells (ESCs) have the capability to give rise to various neural system cells. Hence, microfluidic organ-on-a-chip and SCs can be used as potential research tools to study the treatment of central nervous system (CNS) and peripheral nervous system (PNS) disorders. Accordingly, in the present review, we discuss the latest progress in microfluidic brain-on-a-chip as a powerful and advanced technology that can be used in basic studies to investigate normal and abnormal functions of the nervous system.

Quantitative Proteomic Analysis of Cellular Responses to a Designed Amino Acid Feed in a Monoclonal Antibody Producing Chinese Hamster Ovary Cell Line

Background: Chinese hamster ovary (CHO) cell line is considered as the most common cell line in the biopharmaceutical industry because of its capability in performing efficient post-translational modifications and producing the recombinant proteins, which are similar to natural human proteins. The optimization of the upstream process via different feed strategies has a great impact on the target molecule expression and yield. Methods: To determine and understand the molecular events beneath the feed effects on the CHO cell, a label-free quantitative proteomic analysis was applied. The proteome changes followed by the addition of a designed amino acid feed to the monoclonal antibody producing CHO cell line culture medium were investigated. Results: The glutathione synthesis, the negative regulation of the programmed cell death, proteasomal catabolic process, and the endosomal transport pathway were up-regulated in the group fed with a designed amino acid feed compared to the control group. Conclusion: Our findings could be helpful to identify new targets for metabolic engineering.

Nanomedicine and advanced technologies for burns: Preventing infection and facilitating wound healing.

According to the latest report from the World Health Organization, an estimated 265,000 deaths still occur every year as a direct result of burn injuries. A widespread range of these deaths induced by burn wound happens in low- and middle-income countries, where survivors face a lifetime of morbidity. Most of the deaths occur due to infections when a high percentage of the external regions of the body area is affected. Microbial nutrient availability, skin barrier disruption, and vascular supply destruction in burn injuries as well as systemic immunosuppression are important parameters that cause burns to be susceptible to infections. Topical antimicrobials and dressings are generally employed to inhibit burn infections followed by a burn wound therapy, because systemic antibiotics have problems in reaching the infected site, coupled with increasing microbial drug resistance. Nanotechnology has provided a range of molecular designed nanostructures (NS) that can be used in both therapeutic and diagnostic applications in burns. These NSs can be divided into organic and non-organic (such as polymeric nanoparticles (NPs) and silver NPs, respectively), and many have been designed to display multifunctional activity. The present review covers the physiology of skin, burn classification, burn wound pathogenesis, animal models of burn wound infection, and various topical therapeutic approaches designed to combat infection and stimulate healing. These include biological based approaches (e.g. immune-based antimicrobial molecules, therapeutic microorganisms, antimicrobial agents, etc.), antimicrobial photo- and ultrasound-therapy, as well as nanotechnology-based wound healing approaches as a revolutionizing area. Thus, we focus on organic and non-organic NSs designed to deliver growth factors to burned skin, and scaffolds, dressings, etc. for exogenous stem cells to aid skin regeneration. Eventually, recent breakthroughs and technologies with substantial potentials in tissue regeneration and skin wound therapy (that are as the basis of burn wound therapies) are briefly taken into consideration including 3D-printing, cell-imprinted substrates, nano-architectured surfaces, and novel gene-editing tools such as CRISPR-Cas.

Bacteriophages and phage-inspired nanocarriers for targeted delivery of therapeutic cargos.

The main goal of drug delivery systems is to target therapeutic cargoes to desired cells and to ensure their efficient uptake. Recently a number of studies have focused on designing bio-inspired nanocarriers, such as bacteriophages, and synthetic carriers based on the bacteriophage structure. Bacteriophages are viruses that specifically recognize their bacterial hosts. They can replicate only inside their host cell and can act as natural gene carriers. Each type of phage has a particular shape, a different capacity for loading cargo, a specific production time, and their own mechanisms of supramolecular assembly, that have enabled them to act as tunable carriers. New phage-based technologies have led to the construction of different peptide libraries, and recognition abilities provided by novel targeting ligands. Phage hybridization with non-organic compounds introduces new properties to phages and could be a suitable strategy for construction of bio-inorganic carriers. In this review we try to cover the major phage species that have been used in drug and gene delivery systems, and the biological application of phages as novel targeting ligands and targeted therapeutics.

Nanotechnology in diagnosis and treatment of coronary artery disease.

Nanotechnology could provide a new complementary approach to treat coronary artery disease (CAD) which is now one of the biggest killers in the Western world. The course of events, which leads to atherosclerosis and CAD, involves many biological factors and cellular disease processes which may be mitigated by therapeutic methods enhanced by nanotechnology. Nanoparticles can provide a variety of delivery systems for cargoes such as drugs and genes that can address many problems within the arteries. In order to improve the performance of current stents, nanotechnology provides different nanomaterial coatings, in addition to controlled-release nanocarriers, to prevent in-stent restenosis. Nanotechnology can increase the efficiency of drugs, improve local and systematic delivery to atherosclerotic plaques and reduce the inflammatory or angiogenic response after intravascular intervention. Nanocarriers have potential for delivery of imaging and diagnostic agents to precisely targeted destinations. This review paper will cover the current applications and future outlook of nanotechnology, as well as the main diagnostic methods, in the treatment of CAD.