The Principles of Freeze-Drying and Application of Analytical Technologies

Applications of hydrogels in tissue-engineered repairing of temporomandibular joint diseases

Epidemiological studies reveal that symptoms of temporomandibular joint disorders (TMDs) occur in 60-70% of adults. The inflammatory damage caused by TMDs can easily lead to defects in the articular disc, condylar cartilage, subchondral bone and muscle of the temporomandibular joint (TMJ) and cause pain. Despite the availability of various methods for treating TMDs, few existing treatment schemes can achieve permanent recovery. This necessity drives the search for new approaches. Hydrogels, polymers with high water content, have found widespread use in tissue engineering and regeneration due to their excellent biocompatibility and mechanical properties, which resemble those of human tissues. In the context of TMD therapy, numerous experiments have demonstrated that hydrogels show favorable effects in aspects such as articular disc repair, cartilage regeneration, muscle repair, pain relief, and drug delivery. This review aims to summarize the application of hydrogels in the therapy of TMDs based on recent research findings. It also highlights deficiencies in current hydrogel research related to TMD therapy and outlines the broad potential of hydrogel applications in treating TMJ diseases in the future.

Novel nano-in-micro fabrication technique of diclofenac nanoparticles loaded microneedle patches for localised and systemic drug delivery

Diclofenac, a nonsteroidal anti-inflammatory drug, is commonly prescribed for managing osteoarthritis, rheumatoid arthritis, and post-surgical pain. However, oral administration of diclofenac often leads to adverse effects. This study introduces an innovative nano-in-micro approach to create diclofenac nanoparticle-loaded microneedle patches aimed at localised, sustained pain relief, circumventing the drawbacks of oral delivery. The nanoparticles were produced via wet-milling, achieving an average size of 200 nm, and then incorporated into microneedle patches. These patches showed improved skin penetration in ex vivo tests using Franz-cell setups compared to traditional diclofenac formulations. In vivo tests on rats revealed that the nanoparticle-loaded microneedle patches allowed for quick drug uptake and prolonged release, maintaining drug levels in tissues for up to 72 h. With a systemic bioavailability of 57 %, these patches prove to be an effective means of transdermal drug delivery. This study highlights the potential of this novel microneedle delivery system in enhancing the treatment of chronic pain with reduced systemic side effects.

Protective effects of different lyoprotectants on survival of clinical bacterial isolates in a hospital biobank

Nowadays the significant role of biobanks in medical, diagnostic, industrial, and environmental research is well known. Bacterial biobanks could be used as a good resource for designing new treatments, biomedical and industrial researches, and laboratory diagnostics. To have a collection of bacteria from clinical samples and maintain their long-term viability, their preservation needs appropriate protective agents, like cryoprotectants and lyoprotectants. In this study, we collected and characterized Gram-negative and Gram-positive bacteria carrying important antibiotic resistance markers from different clinical samples of hospitalized children. Sucrose (10%), skimmed milk (10%), skimmed milk plus sodium glutamate (10% + 1%), and bovine serum albumin (BSA, 10%) were used as lyoprotectants during the freeze-drying procedure. The survival rate of the lyophilized samples was calculated by dilution plating and measuring the colony forming unit (CFU) after 3 months of storage. The culture analysis results indicated that 25 of the 27 studied bacterial genera (Dilutions 10-3 to 10-6), including Shigella, Methicillin-resistant S. aureus, Acinetobacter spp., Escherichia spp., Pseudomonas spp., Klebsiella spp., Enterococcus spp., were recovered in cultured fractions from all preservation conditions, while 2 genera were only detected in a single preservation condition (2/27, 7.4%). Based on the results, sucrose (10%) and skimmed milk (10%) presented the most protective features. The survival rates varied significantly according to types of the bacteria. Collectively, our results showed a diversity in the recovery of different bacterial genera after lyophilization. While statistically no significant difference was detected among the studied protective agents, sucrose (10%) and skimmed milk (10%) exhibited more effective lyoprotective properties for both Gram-positive and Gram-negative bacteria among the clinical isolates in our study.

Elastic SiC Aerogel for Thermal Insulation: A Systematic Review

SiC aerogels with their lightweight nature and exceptional thermal insulation properties have emerged as the most ideal materials for thermal protection in hypersonic vehicles; However, conventional SiC aerogels are prone to brittleness and mechanical degradation when exposed to complex loads such as shock and mechanical vibration. Hence, preserving the structural integrity of aerogels under the combined influence of thermal and mechanical external forces is crucial not only for stabling their thermal insulation performance but also for determining their practicality in harsh environments. This review focuses on the optimization of design based on the structure-performance of SiC aerogels, providing a comprehensive review of the inherent correlations among structural stability, mechanical properties, and insulation performance. First, the thermal transfer mechanism of aerogels from a microstructural perspective is studied, followed by the relationship between the building blocks of SiC aerogels (0D particles, 1D nanowires/nanofibers) and their compression performance (including compressive resilience, compressive strength, and fatigue resistance). Moreover, the strategy to improve the high-temperature oxidation resistance and insulation performance of SiC aerogels is explored. Lastly, the challenges and future breakthrough directions for SiC aerogels are presented.

Stabilization challenges and aggregation in protein-based therapeutics in the pharmaceutical industry

Protein-based therapeutics have revolutionized the pharmaceutical industry and become vital components in the development of future therapeutics. They offer several advantages over traditional small molecule drugs, including high affinity, potency and specificity, while demonstrating low toxicity and minimal adverse effects. However, the development and manufacturing processes of protein-based therapeutics presents challenges related to protein folding, purification, stability and immunogenicity that should be addressed. These proteins, like other biological molecules, are prone to chemical and physical instabilities. The stability of protein-based drugs throughout the entire manufacturing, storage and delivery process is essential. The occurrence of structural instability resulting from misfolding, unfolding, and modifications, as well as aggregation, poses a significant risk to the efficacy of these drugs, overshadowing their promising attributes. Gaining insight into structural alterations caused by aggregation and their impact on immunogenicity is vital for the advancement and refinement of protein therapeutics. Hence, in this review, we have discussed some features of protein aggregation during production, formulation and storage as well as stabilization strategies in protein engineering and computational methods to prevent aggregation.

Devitrification of lyoprotectants: A critical determinant for bacteriophages inactivation in freeze-drying and storage

Bacteriophages as promising natural antibacterial additives are widely used in food processing and storage. Although freeze-drying is an economical and efficient way to preserve phages, so far there is limited data for phage freeze-drying and key factors that inactivate phages during freeze-drying and storage remain unknown. Here we systemically compared different types of saccharides/polyols (dextran 5000, glucose, sucrose, trehalose, mannitol, and xylitol) as lyoprotectants and their potential ratios for phage freeze-drying. The pH and osmotic pressure tolerance of bacteriophages were determined and all lyoprotectant solutions were within the tolerance range of phages. Combined with thermodynamic data, it was found that only completely vitrified formulations (glucose, sucrose, and trehalose) could preserve phages during freeze-drying. Selected freeze-dried phages were further arranged for an accelerated stability study. Most formulations stored at higher temperatures (≥25 ℃) presented devitrification, resulting in a significant drop in phage titer. 10% (w/v) of sucrose was recommended as the best formulation for freeze-dried phage storage with less devitrification and a better fitting coefficient (R2 = 0.9592) to the Arrhenius equation, predictively reaching shelf-time as 1093.3 days at 4 ℃ storage. These findings implied that the devitrification of lyoprotectants was the critical determinant for bacteriophage inactivation both in freeze-drying and storage.

A comparative study of freeze-drying heat transfer in polymeric vials and glass vials

Implementation of polymeric vials for freeze-dried drug products has been practically non-existent because of unique moisture barrier and thermodynamic technical challenges. Hybrid vials, which combine the benefits of polymer and glass, have been shown to address the challenges of ordinary polymeric vials. Tackling thermodynamic challenges starts with a clear understanding of the heat transfer mechanism. To this end, multi-physics simulations and experimentation were used to compare the heat transfer between hybrid cyclic olefin polymer (COP) vials and borosilicate glass vials during freeze-drying. Parametric models were developed for hybrid COP and glass vials to systematically study the effect of five design parameters based on the arrangement of the vials on a tray inside a lyophilization chamber. Heat transfer in glass vials were dominated by heat conduction with the surrounding vapor, while hybrid COP vials were governed by conduction with the bottom shelf. Furthermore, hybrid COP vials exhibited more consistent heat flow rate and total heat transfer coefficient compared to glass vials, suggesting higher product quality as a result. The distance between adjacent vials and the drug product height were the most important parameters affecting heat transfer irrespective of vial type. Results indicated that hybrid COP vials can be filled to higher fill volumes with higher heat transfer and without the risk of breakage. Results of this study can help design innovative primary packaging systems for freeze drying or optimizing heat transfer for existing glass or hybrid COP vial systems regarding product consistency and drying time.

From cell factories to patients: Stability challenges in biopharmaceuticals manufacturing and administration with mitigation strategies

Active ingredients of biopharmaceuticals consist of a wide array of biomolecular structures, including those of enzymes, monoclonal antibodies, nucleic acids, and recombinant proteins. Recently, these molecules have dominated the pharmaceutical industry owing to their safety and efficacy. However, their manufacturing is hindered by high cost, inadequate batch-to-batch equivalence, inherent instability, and other quality issues. This article is an up-to-date review of the challenges encountered during different stages of biopharmaceutical production and mitigation of problems arising during their development, formulation, manufacturing, and administration. It is a broad overview discussion of stability issues encountered during product life cycle i.e., upstream processing (aggregation, solubility, host cell proteins, color change), downstream bioprocessing (aggregation, fragmentation), formulation, manufacturing, and delivery to patients.

Recent Advances in Biodegradable and Biocompatible Synthetic Polymers Used in Skin Wound Healing

The treatment of skin wounds caused by trauma and pathophysiological disorders has been a growing healthcare challenge, posing a great economic burden worldwide. The use of appropriate wound dressings can help to facilitate the repair and healing rate of defective skin. Natural polymer biomaterials such as collagen and hyaluronic acid with excellent biocompatibility have been shown to promote wound healing and the restoration of skin. However, the low mechanical properties and fast degradation rate have limited their applications. Skin wound dressings based on biodegradable and biocompatible synthetic polymers can not only overcome the shortcomings of natural polymer biomaterials but also possess favorable properties for applications in the treatment of skin wounds. Herein, we listed several biodegradable and biocompatible synthetic polymers used as wound dressing materials, such as PVA, PCL, PLA, PLGA, PU, and PEO/PEG, focusing on their composition, fabrication techniques, and functions promoting wound healing. Additionally, the future development prospects of synthetic biodegradable polymer-based wound dressings are put forward. Our review aims to provide new insights for the further development of wound dressings using synthetic biodegradable polymers.

Thermostability and in vivo performance of AAV9 in a film matrix

Background

Adeno-associated virus (AAV) vectors are stored and shipped frozen which poses logistic and economic barriers for global access to these therapeutics. To address this issue, we developed a method to stabilize AAV serotype 9 (AAV9) in a film matrix that can be stored at ambient temperature and administered by systemic injection.

Methods

AAV9 expressing the luciferase transgene was mixed with formulations, poured into molds and films dried under aseptic conditions. Films were packaged in individual particle-free bags with foil overlays and stored at various temperatures under controlled humidity. Recovery of AAV9 from films was determined by serial dilution of rehydrated film in media and infection of HeLa RC32 cells. Luciferase expression was compared to that of films rehydrated immediately after drying. Biodistribution of vector was determined by in vivo imaging and quantitative real-time PCR. Residual moisture in films was determined by Karl Fischer titration.

Results

AAV9 embedded within a film matrix and stored at 4 °C for 5 months retained 100% of initial titer. High and low viscosity formulations maintained 90 and 85% of initial titer after 6 months at 25 °C respectively. AAV was not detected after 4 months in a Standard Control Formulation under the same conditions. Biodistribution and transgene expression of AAV stored in film at 25 or 4 °C were as robust as vector stored at −80 °C in a Standard Control Formulation.

Conclusions

These results suggest that storage of AAV in a film matrix facilitates easy transport of vector to remote sites without compromising in vivo performance.

Advances in drying techniques for retention of antioxidants in agro produces

Antioxidants are compounds that are essential for the human body which prevents cell from disease causing free radicals. Antioxidants are present in a wide range of fruits, vegetables, and spices. However, a considerable amount of antioxidants is lost during the post-harvest drying operation of agro produces for their shelf-life enhancement. Hence, retention of antioxidants becomes utmost importance in preserving the nutritional aspects of fruits and vegetables. Compared to conventional hot air drying, methods like freeze drying, vacuum drying, and dehumidified drying helps in the retention of antioxidants. However, the drawbacks prevalent in current drying practices, such as high-power consumption and high capital cost, could be eliminated by adopting novel drying mechanisms. This review focuses on various pretreatment methods like ultra-sonication, high pressure processing, pulsed electric field and ethanol treatment prior to drying operation helps in enhancing the drying efficiency with maximum retention of antioxidants. In addition, hybrid drying technologies such as microwave assisted drying, IR-radiated drying and electro-magnetic assisted drying methods also could significantly improve the retention of antioxidants.HIGHLIGHTSDrying is the most commonly adopted unit operation for enhancing the shelf life of perishable agro produces.However, drying is accompanied by loss of bioactive, color, texture, and sensory attributes.Compared to conventional drying techniques like hot air drying, methods like freeze drying, vacuum drying and dehumidified drying helps in the retention of antioxidants present in agro/food produces.Pretreatment methods like Ozonation, ultra-sonication, and UV radiation prior to drying are also found to improve the drying performance with good retention of antioxidants.Recent developments like microwave-assisted and IR-assisted drying methods perform well in the retention of antioxidants with less energy consumption.

Potential Anti-Inflammatory Effects of a New Lyophilized Formulation of the Conditioned Medium Derived from Periodontal Ligament Stem Cells

The mesenchymal stem cells’ (MSCs) secretome includes the bioactive molecules released in the conditioned medium (CM), such as soluble proteins, free nucleic acids, lipids and extracellular vesicles. The secretome is known to mediate some of the beneficial properties related to MSCs, such as anti-inflammatory, anti-apoptotic and regenerative capacities. In this work, we aim to evaluate the anti-inflammatory potential of a new lyophilized formulation of CM derived from human periodontal ligament stem cells (hPDLSCs). With this aim, we treat hPDLSCs with lipopolysaccharide (LPS) and test the anti-inflammatory potential of lyophilized CM (LYO) through the evaluation of wound closure, transcriptomic and immunofluorescence analysis. LPS treatment increased the expression of TLR4 and of genes involved in its signaling and in p38 and NF-κB activation, also increasing the expression of cytokines and chemokines. Interestingly, LYO downregulated the expression of genes involved in Toll-like receptor 4 (TLR-4), nuclear factor kappa light chain enhancer of activated B cells (NF-κB) and p38 signaling. As a consequence, the genes encoding for cytokines and chemokines were also downregulated. Immunofluorescence acquisitions confirmed the downregulation of TLR-4 and NF-κB with the LYO treatment. Moreover, the LYO treatment also increased hPDLSCs’ migration. LYO was demonstrated to contain transforming growth factor (TGF)-β3 and vascular endothelial growth factor (VEGF). These results suggest that LYO represents an efficacious formulation with anti-inflammatory potential and highlights lyophilization as a valid method to produce stable formulations of MSCs’ secretome.

OUP accepted manuscript

Advances in regenerative medicine manufacturing continue to be a priority for achieving the full commercial potential of important breakthrough therapies. Equally important will be the establishment of distribution chains that support the transport of live cells and engineered tissues and organs resulting from these advanced biomanufacturing processes. The importance of a well-managed distribution chain for products requiring specialized handling procedures was highlighted during the COVID-19 pandemic and serves as a reminder of the critical role of logistics and distribution in the success of breakthrough therapies. This perspective article will provide insight into current practices and future considerations for creating global distribution chains that facilitate the successful deployment of regenerative medicine therapies to the vast number of patients that would benefit from them worldwide.

Dental Mesenchymal Stem Cell Secretome: An Intriguing Approach for Neuroprotection and Neuroregeneration

Mesenchymal stem cells (MSCs) are known for their beneficial effects and regenerative potential. In particular, dental-derived MSCs have the advantage of easier accessibility and a non-invasive isolation method. Moreover, thanks to their neural crest origin, dental MSCs seem to have a more prominent neuroregenerative potential. Indeed, in basal conditions they also express neuronal markers. However, it is now well known that the beneficial actions of MSCs depend, at least in part, on their secretome, referring to all the bioactive molecules released in the conditioned medium (CM) or in extracellular vesicles (EVs). In this review we focus on the applications of the secretome derived from dental MSCs for neuroregeneration and neuroprotection. The secretomes of different dental MSCs have been tested for their effects for neuroregenerative purposes, and the secretomes of dental pulp stem cells and stem cells from human exfoliated deciduous teeth are the most studied. Both the CM and EVs obtained from dental MSCs showed that they are able to promote neurite outgrowth and neuroprotective effects. Interestingly, dental-derived MSC secretome showed stronger neuroregenerative and neuroprotective effects compared to that obtained from other MSC sources. For these reasons, the secretome obtained from dental MSCs may represent a promising approach for neuroprotective treatments.

Transferable, easy-to-use and room-temperature-storable PCR mixes for microfluidic molecular diagnostics

As the outbreak of coronavirus disease 2019 (COVID-19), on-site molecular diagnosis is becoming increasingly important. In this study, a freeze-drying method was introduced for PCR reagents to meet the requirements of microfluidic molecular diagnosis. Using this method, PCR components were pre-mixed and freeze-dried as a bead, which could be transferred into microfluidic chips easily. As this bead only required reconstitution in water, operational steps of PCR were simplified, pipetting errors and errors associated with improper handling of wet reagents could also be reduced. In addition, 19 PCR mixes for different targets (including both RNA and DNA) detection were stable when stored at room temperature (18-25 °C) for 1-2 years and may be stored longer as activity monitoring remains ongoing. To shorten the stability testing time, accelerated stability testing at higher temperatures was proposed. The evaluation periods of the freeze-dried PCR mixes were shortened to less than one month when stored at 56 °C and 80 °C. When attempts were further tried to predict the shelf lives for freeze-dried PCR mixes, our findings challenged the classic view of the Q₁₀ method as a prediction model for freeze-dried PCR mixes and confirmed for the first time that this prediction was influenced by different factors at varying degrees. These studies and findings are important for the development of molecular diagnosis at both central laboratories and resource-limited areas.

Technologies and Applications Toward Preservation of Cells in a Dry State for Therapies

Cell-based therapeutics promise to transform the treatment of a wide range of diseases, many of which, up to this point, are incurable. During the past decade, an increasing number of cell therapies have been approved by government regulatory agencies in the United States, Europe, and Japan. Thousands of clinical trials based on live cell therapies are now taking place around the world. But most of these live cell therapies face temporal and/or spatial distances between manufacture and administration, posing a risk of degradation in potency. Cryopreservation has become the predominant biobanking approach to maintain the product's safety and efficacy during transportation and storage. However, the necessity of cryogenic shipment and storage could limit patient access to these emerging therapies and increase the costs of logistics. In the (bio)pharmaceutical industries, freeze-drying and desiccation are established preservation procedures for manufacturing small molecule drugs, liposomes, and monoclonal antibodies. Over the past two decades, there has been a growing body of research exploring the freeze-drying or drying of mammalian cells, with varying degrees of success. This article provides an overview of the technologies that were adopted or developed in these pioneering studies, paving the road toward the preservation of cell-based therapeutics in a dry state for biomanufacturing.