Microbiological and chemical hazards in cultured meat and methods for their detection

Cultured meat, which involves growing meat in a laboratory rather than breeding animals, offers potential benefits in terms of sustainability, health, and animal welfare compared to conventional meat production. However, the cultured meat production process involves several stages, each with potential hazards requiring careful monitoring and control. Microbial contamination risks exist in the initial cell collection from source animals and the surrounding environment. During cell proliferation, hazards may include chemical residues from media components such as antibiotics and growth factors, as well as microbial issues from improper bioreactor sterilization. In the differentiation stage where cells become muscle tissue, potential hazards include residues from scaffolding materials, microcarriers, and media components. Final maturation and harvesting stages risk environmental contamination from nonsterile conditions, equipment, or worker handling if proper aseptic conditions are not maintained. This review examines the key microbiological and chemical hazards that must be monitored and controlled during the manufacturing process for cultured meats. It describes some conventional and emerging novel techniques that could be applied for the detection of microbial and chemical hazards in cultured meat. The review also outlines the current evolving regulatory landscape around cultured meat and explains how thorough detection and characterization of microbiological and chemical hazards through advanced analytical techniques can provide crucial data to help develop robust, evidence-based food safety regulations specifically tailored for the cultured meat industry. Implementing new digital food safety methods is recommended for further research on the sensitive and effective detection of microbiological and chemical hazards in cultured meat.

Cultivation of Bovine Mesenchymal Stem Cells on Plant-Based Scaffolds in a Macrofluidic Single-Use Bioreactor for Cultured Meat

Reducing production costs, known as scaling, is a significant obstacle in the advancement of cultivated meat. The cultivation process hinges on several key components, e.g., cells, media, scaffolds, and bioreactors. This study demonstrates an innovative approach, departing from traditional stainless steel or glass bioreactors, by integrating food-grade plant-based scaffolds and thermoplastic film bioreactors. While thermoplastic films are commonly used for constructing fluidic systems, conventional welding methods are cost-prohibitive and lack rapid prototyping capabilities, thus inflating research and development expenses. The developed laser welding technique facilitates contamination-free and leakproof sealing of polyethylene films, enabling the efficient fabrication of macrofluidic systems with various designs and dimensions. By incorporating food-grade plant-based scaffolds, such as rice seeded with bovine mesenchymal stem cells, into these bioreactors, this study demonstrates sterile cell proliferation on scaffolds within macrofluidic systems. This approach not only reduces bioreactor prototyping and construction costs but also addresses the need for scalable solutions in both research and industrial settings. Integrating single-use bioreactors with minimal shear forces and incorporating macro carriers such as puffed rice may further enhance biomass production in a scaled-out model. The use of food-grade plant-based scaffolds aligns with sustainable practices in tissue engineering and cultured-meat production, emphasizing its suitability for diverse applications.

Affinity chromatography for virus-like particle manufacturing: Challenges, solutions, and perspectives

The increasing medical application of virus-like particles (VLPs), notably vaccines and viral vectors, has increased the demand for commercial VLP production. However, VLP manufacturing has not yet reached the efficiency level achieved for recombinant protein therapeutics, especially in downstream processing. This review provides a comprehensive analysis of the challenges associated with affinity chromatography for VLP purification with respect to the diversity and complexity of VLPs and the associated upstream and downstream processes. The use of engineered affinity ligands and matrices for affinity chromatography is first discussed. Although several representative affinity ligands are currently available for VLP purification, most of them have difficulty in balancing ligand universality, ligand selectivity and mild operation conditions. Then, phage display technology and computer-assisted design are discussed as efficient methods for the rapid discovery of high-affinity peptide ligands. Finally, the VLP purification by affinity chromatography is analyzed. The process is significantly influenced by virus size and variation, ligand type and chromatographic mode. To address the updated regulatory requirements and epidemic outbreaks, technical innovations in affinity chromatography and process intensification and standardization in VLP purification should be promoted to achieve rapid process development and highly efficient VLP manufacturing, and emphasis is given to the discovery of universal ligands, applications of gigaporous matrices and platform technology. It is expected that the information in this review can provide a better understanding of the affinity chromatography methods available for VLP purification and offer useful guidance for the development of affinity chromatography for VLP manufacturing in the decades to come.

Cell culture design for homogeneous proliferation of cells in three-dimensional nonwoven polymer scaffolds

The objective of this study is to establish strategies to uniformly proliferate cells in a three-dimensional nonwoven polyethylene terephthalate (PET)/ethylene vinyl alcohol (EVOH) scaffold by simple adjustments in seeding and culture methods and the scaffold design. The combined dynamic and static seeding (intermittent agitations at 300 rpm with 1 h interval) resulted in the highest seeding efficiency (71%) comparing to the static and continuous agitating seeding methods. Cell-attached scaffolds were cultivated under different conditions. The stirring culture permitted cells to proliferate to a significantly greater extent than the static or agitating cultures, although faster cell proliferation in the outer region of the scaffold was observed. Next, based on this observation, scaffolds were opened with holes to alleviate the cell aggregation. The effect of hole size and number of scaffolds on the distribution of cells proliferated in the scaffold was evaluated. Two of 1-mm holes showed to be an optimal adjustment to allow cells to proliferate in a homogeneous manner. After 14 days culture, both of the holes were filled by cells proliferated with a fourfold increase in the cell number. The cell viability in the scaffolds was also high upon evaluating the live/dead and 3[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) staining examinations. Different cell types of 3T3-L1, C3H/10T1/2, and KUM6 cells showed similar behavior of cell proliferation and distribution in the scaffold, indicating the applicability of the established procedure. It is concluded that the nonwoven PET/EVOH scaffold serves as a potential cell culture substrate for an efficient cell proliferation.

Cell-culture process optimization via model-based predictions of metabolism and protein glycosylation

In order to meet the rising demand for biologics and become competitive on the developing biosimilar market, there is a need for process intensification of biomanufacturing processes. Process development of biologics has historically relied on extensive experimentation to develop and optimize biopharmaceutical manufacturing. Experimentation to optimize media formulations, feeding schedules, bioreactor operations and bioreactor scale up is expensive, labor intensive and time consuming. Mathematical modeling frameworks have the potential to enable process intensification while reducing the experimental burden. This review focuses on mathematical modeling of cellular metabolism and N-linked glycosylation as applied to upstream manufacturing of biologics. We review developments in the field of modeling cellular metabolism of mammalian cells using kinetic and stoichiometric modeling frameworks along with their applications to simulate, optimize and improve mechanistic understanding of the process. Interest in modeling N-linked glycosylation has led to the creation of various types of parametric and non-parametric models. Most published studies on mammalian cell metabolism have performed experiments in shake flasks where the pH and dissolved oxygen cannot be controlled. Efforts to understand and model the effect of bioreactor-specific parameters such as pH, dissolved oxygen, temperature, and bioreactor heterogeneity are critically reviewed. Most modeling efforts have focused on the Chinese Hamster Ovary (CHO) cells, which are most commonly used to produce monoclonal antibodies (mAbs). However, these modeling approaches can be generalized and applied to any mammalian cell-based manufacturing platform. Current and potential future applications of these models for Vero cell-based vaccine manufacturing, CAR-T cell therapies, and viral vector manufacturing are also discussed. We offer specific recommendations for improving the applicability of these models to industrially relevant processes.

Enhanced Growth of Bacterial Cells in a Smart 3D Printed Bioreactor

In the last decade, there has been a notable advancement in diverse bioreactor types catering to various applications. However, conventional bioreactors often exhibit bulkiness and high costs, making them less accessible to many researchers and laboratory facilities. In light of these challenges, this article aims to introduce and evaluate the development of a do-it-yourself (DIY) 3D printed smart bioreactor, offering a cost-effective and user-friendly solution for the proliferation of various bioentities, including bacteria and human organoids, among others. The customized bioreactor was fabricated under an ergonomic design and assembled with 3D printed mechanical parts combined with electronic components, under 3D printed housing. The 3D printed parts were designed using SOLIDWORKS® CAD Software (2022 SP2.0 Professional version) and fabricated via the fused filament fabrication (FFF) technique. All parts were 3D printed with acrylonitrile butadiene styrene (ABS) in order for the bioreactor to be used under sterile conditions. The printed low-cost bioreactor integrates Internet-of-things (IoT) functionalities, since it provides the operator with the ability to change its operational parameters (sampling frequency, rotor speed, and duty cycle) remotely, via a user-friendly developed mobile application and to save the user history locally on the device. Using this bioreactor, which is adjusted to a standard commercial 12-well plate, proof of concept of a successful operation of the bioreactor during a 2-day culture of Escherichia coli bacteria (Mach1 strain) is presented. This study paves the way for more in-depth investigation of bacterial and various biological-entity growth cultures, utilizing 3D printing technology to create customized low-cost bioreactors.

Advancing our understanding of bioreactors for industrial-sized cell culture: health care and cellular agriculture implications

Bioreactors are advanced biomanufacturing tools that have been widely used to develop various applications in the fields of health care and cellular agriculture. In recent years, there has been a growing interest in the use of bioreactors to enhance the efficiency and scalability of these technologies. In cell therapy, bioreactors have been used to expand and differentiate cells into specialized cell types that can be used for transplantation or tissue regeneration. In cultured meat production, bioreactors offer a controlled and efficient means of producing meat without the need for animal farming. Bioreactors can support the growth of muscle cells by providing the necessary conditions for cell proliferation, differentiation, and maturation, including the provision of oxygen and nutrients. This review article aims to provide an overview of the current state of bioreactor technology in both cell therapy and cultured meat production. It will examine the various bioreactor types and their applications in these fields, highlighting their advantages and limitations. In addition, it will explore the future prospects and challenges of bioreactor technology in these emerging fields. Overall, this review will provide valuable insights for researchers and practitioners interested in using bioreactor technology to develop innovative solutions in the biomanufacturing of therapeutic cells and cultured meat.

Biomanufacturing Recombinantly Expressed Cripto-1 Protein in Anchorage-Dependent Mammalian Cells Growing in Suspension Bioreactors within a Three-Dimensional Hydrogel Microcarrier

Biotherapeutic soluble proteins that are recombinantly expressed in mammalian cells can pose a challenge when biomanufacturing in three-dimensional (3D) suspension culture systems. Herein, we tested a 3D hydrogel microcarrier for a suspension culture of HEK293 cells overexpressing recombinant Cripto-1 protein. Cripto-1 is an extracellular protein that is involved in developmental processes and has recently been reported to have therapeutic effects in alleviating muscle injury and diseases by regulating muscle regeneration through satellite cell progression toward the myogenic lineage. Cripto-overexpressing HEK293 cell lines were cultured in microcarriers made from poly (ethylene glycol)-fibrinogen (PF) hydrogels, which provided the 3D substrate for cell growth and protein production in stirred bioreactors. The PF microcarriers were designed with sufficient strength to resist hydrodynamic deterioration and biodegradation associated with suspension culture in stirred bioreactors for up to 21 days. The yield of purified Cripto-1 obtained using the 3D PF microcarriers was significantly higher than that obtained with a two-dimensional (2D) culture system. The bioactivity of the 3D-produced Cripto-1 was equivalent to commercially available Cripto-1 in terms of an ELISA binding assay, a muscle cell proliferation assay, and a myogenic differentiation assay. Taken together, these data indicate that 3D microcarriers made from PF can be combined with mammalian cell expression systems to improve the biomanufacturing of protein-based therapeutics for muscle injuries.

Advances in bioreactor control for production of biotherapeutic products

Advanced control strategies are well established in chemical, pharmaceutical, and food processing industries. Over the past decade, the application of these strategies is being explored for control of bioreactors for manufacturing of biotherapeutics. Most of the industrial bioreactor control strategies apply classical control techniques, with the control system designed for the facility at hand. However, with the recent progress in sensors, machinery, and industrial internet of things, and advancements in deeper understanding of the biological processes, coupled with the requirement of flexible production, the need to develop a robust and advanced process control system that can ease process intensification has emerged. This has further fuelled the development of advanced monitoring approaches, modeling techniques, process analytical technologies, and soft sensors. It is seen that proper application of these concepts can significantly improve bioreactor process performance, productivity, and reproducibility. This review is on the recent advancements in bioreactor control and its related aspects along with the associated challenges. This study also offers an insight into the future prospects for development of control strategies that can be designed for industrial-scale production of biotherapeutic products.

Development and Scalable Production of Newcastle Disease Virus-Vectored Vaccines for Human and Veterinary Use

The COVID-19 pandemic has highlighted the need for efficient vaccine platforms that can rapidly be developed and manufactured on a large scale to immunize the population against emerging viruses. Viral-vectored vaccines are prominent vaccine platforms that have been approved for use against the Ebola virus and SARS-CoV-2. The Newcastle Disease Virus is a promising viral vector, as an avian paramyxovirus that infects poultry but is safe for use in humans and other animals. NDV has been extensively studied not only as an oncolytic virus but also a vector for human and veterinary vaccines, with currently ongoing clinical trials for use against SARS-CoV-2. However, there is a gap in NDV research when it comes to process development and scalable manufacturing, which are critical for future approved vaccines. In this review, we summarize the advantages of NDV as a viral vector, describe the steps and limitations to generating recombinant NDV constructs, review the advances in human and veterinary vaccine candidates in pre-clinical and clinical tests, and elaborate on production in embryonated chicken eggs and cell culture. Mainly, we discuss the existing data on NDV propagation from a process development perspective and provide prospects for the next steps necessary to potentially achieve large-scale NDV-vectored vaccine manufacturing.