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The global burden of respiratory diseases is enormous, with many millions of people suffering and dying prematurely every year. The global COVID-19 pandemic witnessed recently, along with increased air pollution and wildfire events, increases the urgency of identifying the most effective therapeutic measures to combat these diseases even further. Despite increasing expenditure and extensive collaborative efforts to identify and develop the most effective and safe treatments, the failure rates of drugs evaluated in human clinical trials are high. To reverse these trends and minimize the cost of drug development, ineffective drug candidates must be eliminated as early as possible by employing new, efficient, and accurate preclinical screening approaches. Animal models have been the mainstay of pulmonary research as they recapitulate the complex physiological processes, Multiorgan interplay, disease phenotypes of disease, and the pharmacokinetic behavior of drugs. Recently, the use of advanced culture technologies such as organoids and lung-on-a-chip models has gained increasing attention because of their potential to reproduce human diseased states and physiology, with clinically relevant responses to drugs and toxins. This review provides an overview of different animal models for studying respiratory diseases and evaluating drugs. We also highlight recent progress in cell culture technologies to advance integrated models and discuss current challenges and present future perspectives.

Separation and enrichment of target cells prior to downstream analyses is an essential pre-treatment step in many biomedical and clinical assays. Separation techniques utilizing simple, cost-effective, and user-friendly devices are highly desirable, both in the lab and at the point of need. Passive microfluidic approaches, especially inertial microfluidics, fit this brief perfectly and are highly desired. Using an optimized additive manufacturing technique, we developed a zigzag microchannel for rigid inertial separation and enrichment, hereafter referred to as Z-RISE. We empirically showed that the Z-RISE device outperforms equivalent devices based on curvilinear (sinusoidal), asymmetric curvilinear, zigzag with round corners, or square-wave formats and modelled this behavior to gain a better understanding of the physics underpinning the improved focusing and separation performance. The comparison between rigid and soft zigzag microchannels reveals that channel rigidity significantly affects and enhances the focusing performance of the microchannel. Compared to other serpentine microchannels, zigzag microfluidics demonstrates superior separation and purity efficiency due to the sudden channel cross-section expansion at the corners. Within Z-RISE, particles are aligned in either double-side or single-line focusing positions. The transition of particles from a double-focusing line to a single focusing line introduced a new phenomenon referred to as the plus focusing position. We experimentally demonstrated that Z-RISE could enrich leukocytes and their subtypes from diluted and RBC lysed blood while depleting dead cells, debris, and RBCs. Z-RISE was also shown to yield outstanding particle or cell concentration with a concentration efficiency of more than 99.99%. Our data support the great potential of Z-RISE for applications that involve particle and cell manipulations and pave the way for commercialization perspective in the near future. Refereed/Peer-reviewed

Microbial populations play a crucial role in human health and the development of many diseases. These diseases often arise from the explosive proliferation of opportunistic bacteria, such as those in the nasal cavity. Recently, there have been increases in the prevalence of these opportunistic pathogens displaying antibiotic resistance. Thus, the study of the nasal microbiota and its bacterial diversity is critical in understanding pathogenesis and developing microbial-based therapies for well-known and emerging diseases. However, the isolation and analysis of these populations for clinical study complicates the already challenging task of identifying and profiling potentially harmful bacteria. Existing methods are limited by low sample throughput, expensive labeling, and low recovery of bacteria with ineffective removal of cells and debris. In this study, we propose a novel microfluidic channel with a zigzag configuration for enhanced isolation and detection of bacteria from human clinical nasal swabs. This microfluidic zigzag channel separates the bacteria from epithelial cells and debris by size differential focusing. As such, pure bacterial cell fractions devoid of large contaminating debris or epithelial cells are obtained. DNA sequencing performed on the separated bacteria defines the diversity and species present. This novel method of bacterial separation is simple, robust, rapid, and cost-effective and has the potential to be used for the rapid identification of bacterial cell populations from clinical samples.

Nutraceuticals have emerged as potential compounds to attenuate the COVID-19 complications. Precisely, these food additives strengthen the overall COVID treatment and enhance the immunity of a person. Such compounds have been used at a large scale, in almost every household due to their better affordability and easy access. Therefore, current research is focused on developing newer advanced formulations from potential drug candidates including nutraceuticals with desirable properties viz, affordability, ease of availability, ease of administration, stability under room temperature, and potentially longer shelf-lives. As such, various nutraceutical-based products such as compounds could be promising agents for effectively managing COVID-19 symptoms and complications. Most importantly, regular consumption of such nutraceuticals has been shown to boost the immune system and prevent viral infections. Nutraceuticals such as vitamins, amino acids, flavonoids like curcumin, and probiotics have been studied for their role in the prevention of COVID-19 symptoms such as fever, pain, malaise, and dry cough. In this review, we have critically reviewed the potential of various nutraceutical-based therapeutics for the management of COVID-19. We searched the information relevant to our topic from search engines such as PubMed and Scopus using COVID-19, nutraceuticals, probiotics, and vitamins as a keyword. Any scientific literature published in a language other than English was excluded. PRACTICAL APPLICATIONS: Nutraceuticals possess both nutritional values and medicinal properties. They can aid in the prevention and treatment of diseases, as well as promote physical health and the immune system, normalizing body functions, and improving longevity. Recently, nutraceuticals such as probiotics, vitamins, polyunsaturated fatty acids, trace minerals, and medicinal plants have attracted considerable attention and are widely regarded as potential alternatives to current therapeutic options for the effective management of various diseases, including COVID-19.

With the global burden of respiratory diseases, rapid identification of the best therapeutic measures to combat these diseases is essential. Animal models and 2D cell culture models do not replicate the findings observed in vivo. To gain deeper insight into lung pathology and physiology, 3D and advanced lung-on-a-chip models have been developed recently. Lung-on-a-chip models more accurately simulate the lung's microenvironment and functions in vivo, resulting in more-accurate assessments of drug safety and effectiveness. This review discusses the transition from 2D to 3D models and the recent advances in lung-on-a-chip platforms, their implementation and the numerous challenges faced. Finally, a general overview of this platform and its potential applications in respiratory disease research and drug discovery is highlighted.

Recently, organ-on-a-chip models, which are microfluidic devices that mimic the cellular architecture and physiological environment of an organ, have been developed and extensively investigated. The chips can be tailored to accommodate the disease conditions pertaining to many organs; and in the case of this review, the lung. Lung-on-a-chip models result in a more accurate reflection compared to conventional in vitro models. Pharmaceutical drug testing methods traditionally use animal models in order to evaluate pharmacological and toxicological responses to a new agent. However, these responses do not directly reflect human physiological responses. In this review, current and future applications of the lung-on-a-chip in the respiratory system will be discussed. Furthermore, the limitations of current conventional in vitro models used for respiratory disease modeling and drug development will be addressed. Highlights of additional translational aspects of the lung-on-a-chip will be discussed in order to demonstrate the importance of this subject for medical research. Refereed/Peer-reviewed

The programmed cell death ligand 1 (PD-L1) protein has emerged as a predictive cancer biomarker and sensitivity to immune checkpoint blockade-based cancer immunotherapies. Current technologies for the detection of protein-based biomarkers, including the enzyme-linked immunosorbent assay (ELISA), have limitations such as low sensitivity and limit of detection (LOD) in addition to degradation of antibodies in exposure to environmental changes such as temperature and pH. To address these issues, we have proposed a metal-organic framework (MOF)-based ELISA for the detection of the PD-L1. A protective coating based on Zeolitic Imidazolate Framework 8 (ZIF-8) MOF thin film and polydopamine-polyethylenimine (PDA-PEI) was introduced on an ELISA plate for the improvement of antibody immobilization. Sensitivity and LOD of the resulting platform were compared with a conventional ELISA kit, and the bioactivity of the antibody in the proposed immunoassay was investigated in response to various pH and temperature values. The LOD and sensitivity of the MOF-based PD-L1 ELISA were 225 and 15.12 times higher, respectively, compared with those of the commercial ELISA kit. The antibody@ZIF-8/PDA-PEI was stable up to 55 °C and the pH range 5-10. The proposed platform can provide sensitive detection for target proteins, in addition to being resistant to elevated temperature and pH. The proposed MOF-based ELISA has significant potential for the clinical and diagnostic studies.

Respiratory diseases contribute to a significant percentage of mortality and morbidity worldwide. The circadian rhythm is a natural biological process where our bodily functions align with the 24 h oscillation (sleep–wake cycle) process and are controlled by the circadian clock protein/gene. Disruption of the circadian rhythm could alter normal lung function. Chronotherapy is a type of therapy provided at specific time intervals based on an individual’s circadian rhythm. This would allow the drug to show optimum action, and thereby modulate its pharmacokinetics to lessen unwanted or unintended effects. In this review, we deliberated on the recent advances employed in chrono-targeted therapeutics for chronic respiratory diseases.

Pharmacogenomics (PGx) is increasingly being recognized as a potential tool for improving the efficacy and safety of drug therapy. Therefore, several efforts have been undertaken globally to facilitate the implementation process of PGx into routine clinical practice. Part of these efforts include the formation of PGx working groups working on PGx research, synthesis, and dissemination of PGx data and creation of PGx implementation strategies. In Asia, the Southeast Asian Pharmacogenomics Research Network (SEAPharm) is established to enable and strengthen PGx research among the various PGx communities within but not limited to countries in SEA; with the ultimate goal to support PGx implementation in the region. From the perspective of SEAPharm member countries, there are several key elements essential for PGx implementation at the national level. They include pharmacovigilance database, PGx research, health economics research, dedicated laboratory to support PGx testing for both research and clinical use, structured PGx education, and supportive national health policy. The status of these essential elements is presented here to provide a broad picture of the readiness for PGx implementation among the SEAPharm member countries, and to strengthen the PGx research network and practice in this region.

Biomimetic nanotechnology could serve as an advancement in the domain of drug delivery and diagnosis with the application of natural cell membrane or synthetically-derived membrane nanoparticles (NPs). These biomimetic NPs endow significant therapeutic and diagnostic efficacy by their unique properties, such as immune invasion and better targeting ability. Additionally, these NPs have a unique ability to retain the inherent properties of cell membrane and membrane's intrinsic functionalities, which helps them to exhibit superior therapeutic effects. In this review, we describe how these membrane-clocked NPs endow superior therapeutic effects by immune invasion; along with this, the development of membrane-coated NPs and their method of preparation and characterization has been clearly described in the manuscript. Moreover, Various developed membrane-coated NPs such as red blood cell membrane-coated NPs, white blood cells membrane-coated NPs, platelet membrane coated, cancer cell membrane coated, bacterial membrane vesicles and, mesenchymal stem cells membrane-coated NPs have been established in this manuscript. At last, the discussion on the role of membrane-coated NPs as theranostics, and notably, the literature that demonstrates the shreds of evidences of these NPs in targeting and neutralizing the SARS-CoV-2 virus have also been incorporated.

Obstructive sleep apnea (OSA) is a chronic disorder that involves a decrease or complete cessation of airflow during sleep. It occurs when the muscles supporting the soft tissues in the throat relax during sleep, causing narrowing or closure of the upper airway. Sleep apnea is a serious medical condition with an increased risk of cardiovascular complications and impaired quality of life. Continuous positive airway pressure (CPAP) is the most effective treatment for moderate to severe cases of OSA and is effective in mild sleep apnea. However, CPAP therapy is associated with the development of several nasal side effects and is inconvenient for the user, leading to low compliance rates. The effects of CPAP treatment on the upper respiratory system, as well as the pathogenesis of side effects, are incompletely understood and not adequately researched. To better understand the effects of CPAP treatment on the upper respiratory system, we developed an in vitro 3D-printed microfluidic platform. A nasal epithelial cell line, RPMI 2650, was then exposed to certain conditions to mimic the in vivo environment. To create these conditions, the microfluidic device was utilized to expose nasal epithelial cells grown and differentiated at the air–liquid interface. The airflow was similar to what is experienced with CPAP, with pressure ranging between 0 and 20 cm of H2O. Cells exposed to pressure showed decreased barrier integrity, change in cellular shape, and increased cell death (lactate dehydrogenase release into media) compared to unstressed cells. Stressed cells also showed increased secretions of inflammatory markers IL-6 and IL-8 and had increased production of ATP. Our results suggest that stress induced by airflow leads to structural, metabolic, and inflammatory changes in the nasal epithelium, which may be responsible for developing nasal side-effects following CPAP treatment.

Organ-on-a-chip is a microfluidic cell culture model that replicates key organ-specific microarchitecture and pathophysiology in vitro. The current methods to fabricate these devices rely on softlithography, which is usually tedious, laborious, and requires adroit users as well as cleanroom facilities. Recently, the use of 3D-printing technologies for the rapid fabrication of molds for polydimethylsiloxane (PDMS) casting is on the rise. However, most of the 3D-printed materials are unsuitable for PDMS casting. To address this issue, we have improved the existing techniques and introduced a modified protocol for the surface treatment of 3D-printed molds, making them ideal for repeated long-term PDMS casting. Using this protocol, we have fabricated a simple open well lung-on-a-chip model to simulate the in vivo environment of airway at air-liquid interface under dynamic condition. To validate the functionality of the developed chip, Calu-3 cells were cultured in the chip and maintained at an air-liquid interface. The model demonstrated that the cultured cells replicated the 3D culture-specific-morphology, maintained excellent barrier integrity, secreted mucus, and expressed cell surface functional P-glycoprotein; all indicative of a promising in vitro model for permeability assays, toxicological tests, and pulmonary drug delivery studies. To validate the suitability of this lung-on-a-chip in vitro model, the effects of cigarette smoke extract (CSE) on Interleukin-6 (IL-6) and Interleukin-8 (IL-8) release from cultured Calu-3 cells were examined. CSE treated cells showed significantly higher secretion of IL-6 and IL-8 over 24 h compared to the cells treated with both CSE and Budesonide, an anti-inflammatory drug. Moreover, our results illustrated that CSE reduced the expression of E-cadherin as an adherent junctional protein. In conclusion, the proposed protocol demonstrated an easy and low-cost fabrication technique which will allow a biologist with minimal technical skills to rapidly prototype molds for different/versatile organ-on-a-chip models.