Freeze-drying of proteins: some emerging concerns

Chitin-amended media: Improving efficacy of Cordyceps fumosorosea as a control agent of Cydia pomonella

The microbial control of insect pests such as the codling moth Cydia pomonella is a major challenge in the apple industry. This study investigates the potential of chitin-amended media to improve the efficacy of the entomopathogenic fungus Cordyceps fumosorosea strain JKI-BI-1496 for control of C. pomonella. Chitin, a key component of insect exoskeletons, colloidal chitin (CC) or chitosan were added in two concentrations to the liquid growth media. Only by the amendment of 0.5 % chitosan significant higher numbers of spores were formed whereas the highest biomass was achieved by amendment of chitin. Spores produced in chitosan had no significant effect on the mortality of C. pomonella. But media containing 1 % colloidal chitin (CC) significantly enhanced the efficacy of C. fumosorosea. To achieve 75 % mortality only 1.6 × 107 submerged spores/mL were needed in comparison of over four times higher concentrations in media without CC or chitin. However, while 1 % CC positively impacted spore viability during the freeze-drying formulation process, it had a detrimental effect on the fungus's resilience under prolonged sunlight exposure. These findings provide valuable insights into optimizing media and formulations to enhance the effectiveness of C. fumosorosea in biological control, particularly by improving spore production and formulation processes.

Formation of ternary complexes of carboxymethyl cellulose, soy protein isolate and curcumin using dielectric barrier discharge plasma technology for encapsulation of curcumin

The aim of this study was to assess how the order of compound addition affects the formation of binary and ternary complexes of carboxymethyl cellulose (CMC), soy protein isolate (SPI), and curcumin (CUR) when using dielectric barrier discharge (DBD) plasma treatment. Then, the ternary complex efficiency for the CUR encapsulation was evaluated. First, the binary complexes of SPI-CMC, SPI-CUR, and CMC-CUR were prepared using plasma, and then the third compound was added to form the ternary complex. Free amine and degree of glycation, electrophoretic pattern, FTIR, intrinsic fluorescence, sulfhydryl content, zeta potential, and FE-SEM of mixtures and complexes were evaluated. After CUR encapsulation in SPI(CMC-CUR) complex at different ratios, encapsulation efficiency, loading capacity, morphology, particle size, in vitro release and its mechanism, as well as light and thermal stability of CUR loaded complexes were evaluated. Results indicated that plasma treatment can create complexes; however, it can affect the properties of compounds. The order of compound addition can affect the physicochemical properties of the complexes produced using plasma. The highest encapsulation efficiency was obtained at a ratio of 1:30 (CUR:Complex), and increased the light and thermal stability of CUR. The results showed that the release follows the Ritger-Peppas model.

Multiple-Channel Funnel Adapted Sensing Tube (MFAST) for the Simple and Duplex Detection of Parasites

Leishmaniasis poses a significant global health threat, infecting millions of people annually, particularly in tropical and subtropical regions. Timely and accurate detection of the Leishmania species is crucial for effective treatment and control of this debilitating disease. This study introduces the multi-channel funnel adapted sensing tube (MFAST) chip, a simple diagnostic tool designed for the rapid detection of Leishmania panamensis. MFAST is fabricated through 3D printing and sacrificial molding of acrylonitrile butadiene styrene (ABS) and the reagents are transported between reservoirs by gravity. We combine experiments and finite element analysis to facilitate smoother fluid flow, improving the overall performance of the device. Highly sensitive and specific RPA-CRISPR/Cas12a assay is utilized in the chip, achieving a detection limit as low as 1000 parasites/mL (detecting as few as 5 parasites per reaction). The multichannel design enables duplex detection, allowing for simultaneous identification of both L. braziliensis and L. panamensis through distinct channels. Furthermore, stability tests indicate that lyophilized reagents retain functionality for up to 15 days when stored at 4 °C, underscoring the potential of this chip for practical diagnostic applications in low-resource settings.

Lyopreservation and Nonionic Decellularization of Human Amnion Scaffolds for Enhancing Regeneration in Chronic Nonhealing Ulcers

Chronic nonhealing ulcers are responsible for considerable morbidity, given the increasing prevalence of type II diabetes and other comorbid conditions that further worsen healing. This study introduced shelf-stable decellularized and lyopreserved human amnion grafts for treating difficult-to-heal wounds. The processing approach (comprising a unique combination of nonionic surfactants and trehalose lyopreservation) applied to develop these bioscaffolds maximized the retention of sulfated glycosaminoglycans while enhancing both tensile property and hydrophilicity. Postprocessing, the tensile properties were found to be similar to human skin (5.33 ± 2.45 MPa). Additionally, the surface hydrophilicity of the lyopreserved grafts was increased. It also exhibited optimum moisture transmissibility (evaluated as per BS EN 13726-2 standards), similar to moist wound dressing (1625 ± 375 g/m2/day). Biochemical attributes including total acid-soluble proteins (481.140 ± 14.95 μg/mL) and collagen (9.01 ± 0.15 mg/mL) were well retained as compared to the fresh membrane. Notably, the sulfated glycosaminoglycan content of the processed grafts was well conserved (there was only a 21.14% reduction, which was substantially lower than the reduction achieved by conventionally used surfactants for processing biological tissues). The regenerative efficacy of these bioactive scaffolds was evaluated through preclinical testing in a diabetic rodent wound model. It showed a 50% reduction in time to heal compared to the standard of care dressings, supported by increased vascular endothelial growth factor (VEGF) expression in the healed tissues. This can be collectively attributed to the conservation of sulfated glycosaminoglycans (GAGs) and the enhanced scaffold tensile quality, which play key roles in promoting angiogenesis, and tissue regeneration in diabetic wound beds. As a result, these grafts are well suited for a variety of soft tissue reconstruction applications and can also serve as bioactive scaffolds for culturing autologous cells, making them versatile tools in regenerative medicine.

A novel alternative fate for shrimp fishery wastes as active ingredients in ecofriendly antifouling paints

This study addresses two environmental issues: the fate of fisheries organic wastes and the marine biofouling control. Marine biofouling continues to pose a significant environmental and economic burden, with existing solutions often being environmentally toxic or prohibitively expensive. Natural products, such as enzymes, have emerged as promising alternatives. Shrimp processing wastes are usually dumped to the environment, although they constitute an important source of marine enzymes. In this context, the present study investigates the potential of enzymatic extract derived from shrimp processing waste as an antifouling agent. We focused on the performance and stability of proteolytic enzymes within the extract under various conditions: exposure to seawater (static and dynamic) over time, and resistance to organic solvents. Additionally, we explored field trials using antifouling paints formulated with shrimp extract and we investigated a versatile and simple technology for extract immobilization. The results demonstrate that proteolytic activity in the shrimp extract remained stable over time in seawater and when exposed to organic solvents. Paints containing this extract completely inhibited macrofouling attachment for 7 months. Interestingly, control panels with deactivated enzymes exhibited macroalgae colonization but also showed reduced macroinvertebrate attachment. This suggests that additional compounds within the extract may have antifouling properties. We successfully produced nanocapsules of alginate-chitosan containing the shrimp extract using electrohydrodynamic atomization. While these nanocapsules show promise, further optimization is required. Overall, this study presents encouraging findings for the use of shrimp waste extract in antifouling paint formulations. This approach offers a potentially low-cost and environmentally friendly solution to the biofouling problem.

2-Propanol Suspension Method to Increase Acetylcholinesterase and Flow Stability on μPADs

Ensuring detection performance and shelf life is crucial for analytical devices. Advances in materials and reaction mechanisms have improved detection performance, yet extending the operational lifetime of microfluidic paper-based analytical devices (μPADs)─especially those reliant on sensitive enzymes─remains a challenge. Here, we present an alternative to air-drying and lyophilization: loading enzymes suspended in 2-propanol (iPrOH). By suspending the enzyme in iPrOH, we circumvent the enzyme activity losses commonly associated with freeze-thawing and freeze-drying. Accelerated aging tests, supported by statistical analyses of long-term activity retention (including comparisons over multiple time points), indicate that while conventional methods do not sustain consistent superiority, the iPrOH suspension method maintains higher enzymatic activity over extended periods. By avoiding stabilizers and circumventing the limitations of other techniques, our method enables μPADs to achieve both longevity and stable fluid flow. Thus, we provide a more robust, on-site analytical platform capable of reliable on-site detection.

Biomimetic tubular materials: from native tissues to a unifying view of new vascular, tracheal, gastrointestinal, oesophageal, and urinary grafts

Repairing tubular tissues-the trachea, the esophagus, urinary and gastrointestinal tracts, and the circulatory system-from trauma or severe pathologies that require resection, calls for new, more effective graft materials. Currently, the relatively narrow family of materials available for these applications relies on synthetic polymers that fail to reproduce the biological and physical cues found in native tissues. Mimicking the structure and the composition of native tubular tissues to elaborate functional grafts is expected to outperform the materials currently in use, but remains one of the most challenging goals in the field of biomaterials. Despite their apparent diversity, tubular tissues share extensive compositional and structural features. Here, we assess the current state of the art through a dual layer model, reducing each tissue to an inner epithelial layer and an outer muscular layer. Based on this model, we examine the current strategies developed to mimic each layer and we underline how each fabrication method stands in providing a biomimetic material for future clinical translation. The analysis provided here, addressed to materials chemists, biomaterials engineers and clinical staff alike, sets new guidelines to foster the elaboration of new biomimetic materials for effective tubular tissue repair.

Are Collagen Protons Visible with the Zero Echo Time (ZTE) Magnetic Resonance Imaging Sequence: A D2O Exchange and Freeze-Drying Study

It is known that ultrashort echo time (UTE) magnetic resonance imaging (MRI) sequences can detect signals from water protons but not collagen protons in short T2 species such as cortical bone and tendons. However, whether collagen protons are visible with the zero echo time (ZTE) MRI sequence is still unclear. In this study, we investigated the potential of the ZTE MRI sequence on a clinical 3T scanner to directly image collagen protons via D2O exchange and freeze-drying experiments. ZTE and UTE MRI sequences were employed to image fully hydrated bovine cortical bone (n = 10) and human patellar tendon (n = 1) specimens. Then, each specimen was kept in a 30 mL syringe filled with D2O solution for two days. Fresh D2O was flushed every 2 h to reach a more complete D2O-H2O exchange. Later, the samples were lyophilized for over 40 h and then sealed in tubes. Finally, the samples were brought to room temperature and visualized using the identical 3D ZTE and UTE sequences. All hydrated bone and tendon specimens showed high signals with ZTE and UTE sequences. However, all specimens showed zero signal after the D2O exchange and freeze-drying procedures. Therefore, similar to UTE imaging, the signal source in ZTE imaging is water. The ZTE sequence cannot directly detect signals from collagen protons in bone and tendons.

The impacts of freeze-drying-induced stresses on the quality of meat and aquatic products: Mechanisms and potential solutions to acquire high-quality products

Freeze-drying is a preservation method known for its effectiveness in dehydrating food products while minimizing their deterioration. However, protein denaturation and oxidation during freezing and drying can degrade the quality of meat and aquatic products. Therefore, finding the strategies to ensure the dried products' sensory, functional, and nutritional attributes is crucial. This study aimed to summarize protein denaturation mechanisms and overall quality changes in meat and aquatic products during freezing and drying, while also exploring methods for quality control. Different freeze-drying conditions result in varying levels of oxidation and functionality in meat and aquatic products, leading to changes in quality, such as altered fatty and amino acid compositions, protein digestibility, and sensory attributes. To obtain high-quality dried products by freeze-drying, several parameters should be considered, including sample type, freezing and drying temperatures, moisture content, pulverization effects, and storage conditions.

Fabrication and characterization of whey protein isolate-tryptophan nanoparticles by pH-shifting combined with heat treatment

L-Tryptophan (Trp) is an essential amino acid with numerous health benefits. However, incorporating Trp into food products is limited due to its pronounced bitter taste. Encapsulating Trp in nanoparticles by using other natural biopolymers is a potential strategy to mask the bitter taste of Trp in the final products. Whey protein isolate (WPI), composed of alpha-lactalbumin (α-LA), bovine serum albumin (BSA), and beta-lactoglobulin (β-LG), has played a crucial role in delivering bioactive compounds. In order to incorporate Trp within WPI, the present study used a combination of pH-shifting andthermal treatment to fabricatewhey protein isolate-tryptophan nanoparticles (WPI-Trp-NPs). During the pH-shifting technique, WPI unfolds at high pH, such as pH 11, and the dissociated WPI molecules are refolded when pH is shifted back to neutral, creating particles with uniform dispersion and encapsulating smaller particles surrounding them in solution. Further, the well-distributed nanoparticles formed by pH-shifting might encourage the formation of more uniform nanoparticles during subsequent thermal treatment. TheWPI-Trp particles have an average particle size of 110.1 nm and a low average PDI of 0.20. Fluorescence spectroscopy confirmed the encapsulation of Trp by WPI, which shows higher fluorescence when the Trp is encapsulated by the WPI. Surface hydrophobicity, circular dichroism, particle size, free sulfhydryl, and antioxidant activity were used to characterize the WPI-Trp-NPs. WPI-Trp-NPs formed by pH-shifting combined with heating showed a higher surface hydrophobicity and free sulfhydryl content than the untreated WPI-Trp mixture. The conversion of α-helix into random coil in the WPI secondary structure indicated a more disordered structure of the modified whey protein. Molecular docking results indicate the interactions between Trp and WPI, including alpha-lactalbumin (α-LA), bovine serum albumin, and beta-lactoglobulin (β-LG), were mainly driven by hydrophobic interactions and hydrogen bonding. The binding affinity between Trp and these proteins was ranked as α-LA>BSA>β-LG. The combination of pH-shifting and heating improved the functionalityof WPI and was an effective way to fabricate WPI-Trp nanoparticles.

Effects of spray drying and freeze drying on the protein profile of whey protein concentrate

Whey protein concentrate (WPC) is consumed for its high protein content. The structure and biological functionality of whey proteins in WPC powders may be affected by the drying technique applied. However, the specific impact of spray drying and freeze drying on the overall protein profile of whey protein derived from sweet whey streams at scale is unknown. Herein, we examine the effects of commercial-scale freeze drying and spray drying on WPC to determine which method better preserves bioactive whey proteins, with the goal of helping the dairy industry create high-value products that meet the growing consumer demand for functional dairy products. WPCs were produced from pasteurized liquid whey using either a commercial spray dryer or freeze dryer. A variety of analytical techniques, including enzyme-linked immunosorbent assay, polyacrylamide gel electrophoresis, and bottom-up proteomics using liquid chromatography-tandem mass spectroscopy were used to identify, quantify, and compare the retention of bioactive proteins in WPC before and after spray drying and freeze drying. In addition, the extent of denaturation was studied via solubility testing, differential scanning calorimetry, and hydrophobicity assessment. There was little to no difference in the retention or denaturation of key bioactive proteins between spray-dried and freeze-dried WPC powders. There was a higher percentage of select Maillard modifications in freeze-dried and spray-dried powders than in the control. The lack of significant differences between spray drying and freeze drying identified herein indicates that freeze drying does not meaningfully improve retention of bioactive proteins compared with spray drying when performed after multiple pasteurization steps. PRACTICAL APPLICATION: This study aimed to provide insight into the impacts of spray drying versus freeze drying on whey proteins. Overall, our results indicate that for commercial dairy processing that involves multiple rounds of pasteurization, freeze drying does not meaningfully improve the retention of bioactive proteins compared with spray drying. These findings may help the food and dairy industry make informed decisions regarding the processing of its whey protein products to optimize nutritional value.

Assessment of bovine milk exosome preparation and lyophilized powder stability

Exosomes are cell-derived nanovesicles that play a crucial role in intercellular communication, presenting promising potential as biomarkers and therapeutic agents. Bovine milk exosomes (MK-Exo) show production scalability and cost-effectiveness, offering distinct advantages over cell-derived exosomes. However, exosome storage and transportation are challenging owing to their unstable nature, necessitating preservation at ultralow temperatures. Research findings suggest that freeze-drying could provide a viable solution; however, different sources of exosomes may require specific protocols. In this study, we aimed to successfully isolate high-purity MK-Exo and develop a specialized freeze-drying and lyophilization method for improved long-term preservation of MK-Exo. Specifically, the stability of the lyophilized MK-Exo was evaluated using storage stability tests. Notably, lyophilized MK-Exo remained stable for at least 3 months under high temperature of 50°C and for at least 24 months under low temperatures of 2°C-8°C, preserving their physicochemical properties and biological activity. Conclusively, these findings provide a potential solution for ambient-temperature transportation of MK-Exo, facilitating their industrial-scale production.

Assessment of Whole Grain Ancient Wheat Sourdough in Lyophilised and Native Forms for Cookie Formulation

This study explored the potential of two forms of sourdough-native and lyophilised-obtained through the spontaneous fermentation of whole grain flours from ancient wheat varieties, for cookie production. The research involved evaluated the dough's rheological properties through creep and recovery measurements and Mixolab analysis, assessing proximate composition, physical attributes, texture, colour, and sensory characteristics using the Rate-all-that-apply (RATA) method. The rheological analysis revealed that native sourdough significantly impacted dough behaviour, making it more challenging to process. Although differences were observed in the proximate composition, colour, and texture, these factors did not influence the samples as much as the rheological parameters. Sensory evaluation identified Khorasan lyophilised sourdough, along with its control sample, as the most promising, while modern wheat, spelt, and emmer exhibited potentially undesirable attributes. Based on these findings, it was concluded that lyophilised Khorasan sourdough was very favourable for cookie production and should be considered for further in-depth research and development. This suggests that the lyophilised forms of ancient wheats could offer valuable alternatives for cookie formulation, with implications for both the processing and sensory attributes of the final product.

Effectiveness of Lyoprotectants in Protein Stabilization During Lyophilization

Background: Proteins are commonly used in the healthcare industry to treat various health conditions, and most proteins are sensitive to physical and chemical changes. Lyophilization, also known as freeze-drying, involves sublimating water in the form of ice from a substance at low pressure, forming a freeze-dried powder that increases its shelf life. Extreme pressure and varying temperatures in the freeze-drying process may damage the protein's structural integrity. Lyoprotectants are commonly used to protect protein conformations. It is important to choose a suitable lyoprotectant to ensure optimal effectiveness. Method: Twenty articles screened from Scopus, Web of Science, and PubMed were included in this review that discussed potential lyoprotectants and their effectiveness with different protein models. Results: Lyoprotectants were categorized into sugars, polyols, surfactants, and amino acids. Lyoprotectants can exhibit significant protective effects towards proteins, either singularly or in combination with another lyoprotectant. They exert various interactions with the protein to stabilize it, such as hydrogen bonding, hydrophobic interactions, electrostatic interactions, and osmoprotection. Conclusions: This review concludes that disaccharides are the most effective lyoprotectants, while other groups of lyoprotectants are best used in combination with other lyoprotectants.

The effect of polysaccharide type on dielectric barrier discharge (DBD) plasma glycosylation of sodium caseinate-part I: Physicochemical, structural and thermal properties

This study aimed to investigate the impact of polysaccharide type on the physicochemical, structural, and thermal properties of dielectric barrier discharge (DBD) plasma glycosylated sodium caseinate (SC). The polysaccharides Quince seed gum (QSG), carboxymethyl cellulose (CMC), and maltodextrin (MD) were mixed with SC and treated with DBD plasma at 18 kV for 10 min. The grafting degree, electrophoresis pattern, FTIR, XRD, carbonyl, sulfhydryl, and di-tyrosine content, FE-SEM, color, and thermal properties of SC and its polysaccharide mixtures before and after plasma treatment were analyzed. Results showed that the SC-QSG conjugate had the highest glycation degree and color change after plasma treatment. The SC-CMC and SC-QSG conjugates exhibited disappearance of distinct SC bands in electrophoresis pattern compared to SC. Also, significant changes in functional group and crystallinity were occurred in SC-CMC conjugate. Plasma treatment caused oxidation of SC, but the presence of polysaccharides offered protection against oxidation. The microstructure of SC was altered by mixing with polysaccharides and exposure to plasma. Also, the mixtures indicated higher thermal stability after plasma treatment. Results confirmed that the generation of protein-polysaccharide conjugates through DBD plasma technique was depended on with SC-MD conjugate unable to form through this method.

Pulmonary Inhalation of Biotherapeutics: A Systematic Approach to Understanding the Effects of Atomisation Gas Flow Rate on Particle Physiochemical Properties and Retained Bioactivity

The identification of spray-drying processing parameters capable of producing particles suitable for pulmonary inhalation with retained bioactivity underpins the development of inhalable biotherapeutics. Effective delivery of biopharmaceuticals via pulmonary delivery routes such as dry powder inhalation (DPI) requires developing techniques that engineer particles to well-defined target profiles while simultaneously minimising protein denaturation. This study examines the simultaneous effects of atomisation gas flow rate on particle properties and retained bioactivity for the model biopharmaceutical lysozyme. The results show that optimising the interplay between atomisation gas flow rate and excipient concentration enables the production of free-flowing powder with retained bioactivity approaching 100%, moisture content below 4%, and D50 < 4 µm, at yields exceeding 50%. The developed methodologies inform the future design of protein-specific spray-drying parameters for inhalable biotherapeutics.

Fermenter scale production of recombinant beta-mannanase by E. coli BL21 cells under microaerobic environment

Aim of the study was to optimize and produce beta-mannanase at fermenter scale by using cheaper minimal media. Increased production of beta-mannanase from Microbacterium camelliasinensis CIAB417 was achieved by heterologous expression in E. coli BL21 (DE3). The scale-up production of beta-mannanase was optimized from shake flask to 5-L fermenter. The cost-effective minimal media (M9+e) without any vitamins was found to be most effective and optimized for culturing the cells. The same media displayed no significant fluctuation in the pH while culturing the cells for the production of beta-mannanase both at shake flask and fermenter level. Additionally, E. coli cells were able to produce similar amount of dry cell weight and recombinant beta-mannanase both in the presence of micro and macro-oxygen environment. The optimized media was demonstrated to show no significant drop in pH throughout the recombinant protein production process. In one litre medium, 2.0314 g dry weight of E. coli cells yielded 1.8 g of purified recombinant beta-mannanase. The purified enzyme was lyophilized and demonstrated to hydrolyse locust bean gum to release mannooligosaccharides.

Protecting Proteins from Desiccation Stress Using Molecular Glasses and Gels

Faced with desiccation stress, many organisms deploy strategies to maintain the integrity of their cellular components. Amorphous glassy media composed of small molecular solutes or protein gels present general strategies for protecting against drying. We review these strategies and the proposed molecular mechanisms to explain protein protection in a vitreous matrix under conditions of low hydration. We also describe efforts to exploit similar strategies in technological applications for protecting proteins in dry or highly desiccated states. Finally, we outline open questions and possibilities for future explorations.

Unraveling the potential of non-thermal ultrasonic contact drying for enhanced functional and structural attributes of pea protein isolates: A comparative study with spray and freeze-drying methods

The challenge of preserving the quality of thermal-sensitive polymeric materials specifically proteins during a thermal drying process has been a subject of ongoing concern. To address this issue, we investigated the use of ultrasound contact drying (USD) under non-thermal conditions to produce functionalized pea protein powders. The study extensively examined functional and physicochemical properties of pea protein isolate (PPI) in powder forms obtained through three drying methods: USD (30 °C), spray drying (SD), and freeze drying (FD). Additionally, physical attributes such as powder flowability and color, along with morphological properties, were thoroughly studied. The results indicated that the innovative USD method produced powders of comparable quality to FD and significantly outperformed SD. Notably, the USD-PPI exhibited higher solubility across all pH levels compared to both FD-PPI and SD-PPI. Moreover, the USD-PPI samples demonstrated improved emulsifying and foaming properties, a higher percentage of random coil form (56.2 %), increased gel strength, and the highest bulk and tapped densities. Furthermore, the USD-PPI displayed a unique surface morphology with visible porosity and lumpiness. Overall, this study confirms the effectiveness of non-thermal ultrasound contact drying technology in producing superior functionalized plant protein powders, showing its potential in the fields of chemistry and sustainable materials processing.

Freeze-drying revolution: unleashing the potential of lyophilization in advancing drug delivery systems

Lyophilization also known as freeze-drying is a technique that has been employed to enhance the long-term durability of nanoparticles (NPs) that are utilized for drug delivery applications. This method is used to prevent their instability in suspension. However, this dehydration process can cause stress to the NPs, which can be alleviated by the incorporation of excipients like cryoprotectants and lyoprotectants. Nevertheless, the freeze-drying of NPs is often based on empirical principles without considering the physical-chemical properties of the formulations and the engineering principles of freeze-drying. For this reason, it is crucial to optimize the formulations and the freeze-drying cycle to obtain a good lyophilizate and ensure the preservation of NPs stability. Moreover, proper characterization of the lyophilizate and NPs is of utmost importance in achieving these goals. This review aims to update the recent advancements, including innovative formulations and novel approaches, contributing to the progress in this field, to obtain the maximum stability of formulations. Additionally, we critically analyze the limitations of lyophilization and discuss potential future directions. It addresses the challenges faced by researchers and suggests avenues for further research to overcome these limitations. In conclusion, this review is a valuable contribution to the understanding of the parameters involved in the freeze-drying of NPs. It will definitely aid future studies in obtaining lyophilized NPs with good quality and enhanced drug delivery and therapeutic benefits.

Reexamining the diverse functions of arginine in biochemistry

Arginine in a free-state and as part of peptides and proteins shows distinct tendency to form clusters. In free-form, it has been found useful in cryoprotection, as a drug excipient for both solid and liquid formulations, as an aggregation suppressor, and an eluent in protein chromatography. In many cases, the mechanisms by which arginine acts in all these applications is either debatable or at least continues to attract interest. It is quite possible that arginine clusters may be involved in many such applications. Furthermore, it is possible that such clusters are likely to behave as intrinsically disordered polypeptides. These considerations may help in understanding the roles of arginine in diverse applications and may even lead to better strategies for using arginine in different situations.

Multimodal characterization of the collagen hydrogel structure and properties in response to physiologically relevant pH fluctuations

pH fluctuations within the extracellular matrix (ECM) and its principal constituent collagen, particularly in solid tumors and chronic wounds, may influence its structure and function. Whereas previous research examined the impact of pH on collagen fibrillogenesis, this study focuses on determining how pH fluctuations affect collagen hydrogels that mimic the physiological ECM. Utilizing a type I collagen hydrogel, we examined the influence of pH fluctuations on its structure, properties, and function while keeping the collagen hydrated. We show that collagen's secondary structure remains unaltered during pathologically relevant microenvironmental pH changes. By employing cryo scanning electron microscopy and artificial intelligence-assisted image analysis, we show that at physiological pH, collagen hydrogel presents densely packed, aligned, and elongated fibrils, which upon a decrease to pH 6.5, are transformed into shorter, sparser, and disoriented fibrils. The collagen possesses a higher storage modulus yet a lower permeability at pH 7 and 7.8 compared with pH 6.5 and 7.4. Exposing acidified collagen to a basic buffer reinstates its native structure and viscoelastic properties. Our study offers an innovative approach to analyze and characterize perturbations in hydrated collagen-based systems with potential implications for better understanding and combating disease progression. STATEMENT OF SIGNIFICANCE: As the main component of the extracellular matrix, collagen undergoes conformational changes associated with pH changes during disease. We analyze the impact of pH on pre-formed collagen fibers mimicking healthy tissues subjected to disease, and do not focus on the more studied fibrillogenesis process. Using cryogenic SEM, which allowed imaging close to the native state, we show that even minor fluctuations in the pH affect the collagen thickness, length, fiber alignment, and rheological properties. Following exposure to acidic pH, the collagen had short fibers, lacked orientation, and had low mechanical strength. This acidic collagen restored its original properties after returning to a neutral pH. These findings can help determine how pH changes can be modulated to restore healthy collagen properties.

Protein structure-function continuum model: Emerging nexuses between specificity, evolution, and structure

The rationale for replacing the old binary of structure-function with the trinity of structure, disorder, and function has gained considerable ground in recent years. A continuum model based on the expanded form of the existing paradigm can now subsume importance of both conformational flexibility and intrinsic disorder in protein function. The disorder is actually critical for understanding the protein-protein interactions in many regulatory processes, formation of membrane-less organelles, and our revised notions of specificity as amply illustrated by moonlighting proteins. While its importance in formation of amyloids and function of prions is often discussed, the roles of intrinsic disorder in infectious diseases and protein function under extreme conditions are also becoming clear. This review is an attempt to discuss how our current understanding of protein function, specificity, and evolution fit better with the continuum model. This integration of structure and disorder under a single model may bring greater clarity in our continuing quest for understanding proteins and molecular mechanisms of their functionality.

Essential elements for spatiotemporal delivery of growth factors within bio-scaffolds: A comprehensive strategy for enhanced tissue regeneration

The precise delivery of growth factors (GFs) in regenerative medicine is crucial for effective tissue regeneration and wound repair. However, challenges in achieving controlled release, such as limited half-life, potential overdosing risks, and delivery control complexities, currently hinder their clinical implementation. Despite the plethora of studies endeavoring to accomplish effective loading and gradual release of GFs through diverse delivery methods, the nuanced control of spatial and temporal delivery still needs to be elucidated. In response to this pressing clinical imperative, our review predominantly focuses on explaining the prevalent strategies employed for spatiotemporal delivery of GFs over the past five years. This review will systematically summarize critical aspects of spatiotemporal GFs delivery, including judicious bio-scaffold selection, innovative loading techniques, optimization of GFs activity retention, and stimulating responsive release mechanisms. It aims to identify the persisting challenges in spatiotemporal GFs delivery strategies and offer an insightful outlook on their future development. The ultimate objective is to provide an invaluable reference for advancing regenerative medicine and tissue engineering applications.

Extremozyme-Based Biosensors for Environmental Pollution Monitoring: Recent Developments

Extremozymes combine high specificity and sensitivity with the ability to withstand extreme operational conditions. This work presents an overview of extremozymes that show potential for environmental monitoring devices and outlines the latest advances in biosensors utilizing these unique molecules. The characteristics of various extremozymes described so far are presented, underlining their stability and operational conditions that make them attractive for biosensing. The biosensor design is discussed based on the detection of photosynthesis-inhibiting herbicides as a case study. Several biosensors for the detection of pesticides, heavy metals, and phenols are presented in more detail to highlight interesting substrate specificity, applications or immobilization methods. Compared to mesophilic enzymes, the integration of extremozymes in biosensors faces additional challenges related to lower availability and high production costs. The use of extremozymes in biosensing does not parallel their success in industrial applications. In recent years, the "collection" of recognition elements was enriched by extremozymes with interesting selectivity and by thermostable chimeras. The perspectives for biosensor development are exciting, considering also the progress in genetic editing for the oriented immobilization of enzymes, efficient folding, and better electron transport. Stability, production costs and immobilization at sensing interfaces must be improved to encourage wider applications of extremozymes in biosensors.

Effect of a novel drying method based on supercritical carbon dioxide on the physicochemical properties of sorghum proteins

The aim of this research was to use supercritical carbon dioxide (SC-CO2) drying as a novel approach for generating sorghum protein concentrates/isolates with enhanced functional properties. Sorghum protein extracts were obtained from white whole-grain sorghum flour and were dried by two methods, namely, freeze-drying and SC-CO2 drying. The collected proteins were characterized for their morphology, color, crystallinity, surface hydrophobicity, emulsifying activity index (EAI), creaming index (CI), foaming capacity (FC), foaming stability (FS), protein solubility, chemical interactions, and viscosity. The SC-CO2-dried proteins exhibited higher porosity compared to the freeze-dried ones with smaller particle sizes (∼5.1 vs. 0.4 μm, respectively). The XRD patterns indicated that the SC-CO2-dried proteins had a lower crystallinity than the freeze-dried proteins. However, the surface hydrophobicities of the freeze-dried and SC-CO2-dried proteins were similar. The EAI results showed that the emulsifying activity of freeze-dried protein powder (40.6) was better than that of SC-CO2-dried protein powder (29.8). Nevertheless, the solubility of SC-CO2-dried proteins was higher than that of freeze-dried proteins in most of the pHs investigated. Overall, the proposed SC-CO2 drying method has the potential to generate porous protein powders with improved solubility that can be used in developing functional foods.

Production of freeze-dried beef powder for complementary food: Effect of temperature control in retaining protein digestibility

This study investigated the effect of temperature control during freeze-drying of beef on the in vitro protein digestibility. Frozen (at - 50 °C for 2 days)-then-aged (at 4 °C for 26 days) beef was freeze-dried at 25 °C (FD1) and 2 °C (FD2) to obtain freeze-dried beef powder. Tryptophan fluorescence intensity and total free sulfhydryl groups of beef myofibrillar proteins decreased (P < 0.05) and increased (P < 0.05) after freeze-drying, respectively. In the myosin fraction of FD2, α-helix increased and β-sheet decreased (P < 0.05) compared to raw beef. In contrast, the actin fraction of FD1 showed a decrease in α-helix and increase in β-sheet (P < 0.05) compared to raw beef. The contents of α-amino group and proteins digested to<3 kDa in the in vitro digesta of beef were retained in FD2 while the α-amino group of FD1 decreased (P < 0.05). Therefore, freeze-drying at 2 °C can efficiently retain in vitro protein digestibility of beef.

Multi-omics characterization of NIST seafood reference materials and alternative matrix preparations

The National Institute of Standards and Technology (NIST) has prepared four seafood reference materials (RMs) for use in food safety and nutrition studies: wild-caught and aquacultured salmon (RM 8256 and RM 8257) and wild-caught and aquacultured shrimp (RM 8258 and RM 8259). These materials were characterized using genetic, metabolomic (1H-NMR, nuclear magnetic resonance and LC-HRMS/MS, liquid chromatography high-resolution tandem mass spectrometry), lipidomic, and proteomic methods to explore their use as matrix-matched, multi-omic differential materials for method development towards identifying product source and/or as quality control in untargeted omics studies. The results from experimental replicates were reproducible for each reference material and analytical method, with the most abundant features reported. Additionally, differences between the materials could be detected, where wild-caught and aquacultured seafood could be distinguished using untargeted metabolite, lipid, and protein analyses. Further processing of the fresh-frozen RMs by freeze-drying revealed the freeze-dried seafoods could still be reliably discerned. These results demonstrate the usefulness of these reference materials as tools for omics instrument validation and measurement harmonization in seafood-related studies. Furthermore, their use as differential quality control (QC) materials, regardless of preparation method, may also provide a tool for laboratories to demonstrate proficiency at discriminating between products based on source/species.

Performance of cross-linked enzyme crystals of engineered halohydrin dehalogenase HheG in different chemical reactor systems

Halohydrin dehalogenase HheG is an industrially interesting biocatalyst for the preparation of different β-substituted alcohols starting from bulky internal epoxides. We previously demonstrated that the immobilization of different HheG variants in the form of cross-linked enzyme crystals (CLECs) yielded stable and reusable enzyme immobilizes with increased resistance regarding temperature, pH, and the presence of organic solvents. Now, to further establish their preparative applicability, HheG D114C CLECs cross-linked with bis-maleimidoethane have been successfully produced on a larger scale using a stirred crystallization approach, and their application in different chemical reactor types (stirred tank reactor, fluidized bed reactor, and packed bed reactor) was systematically studied and compared for the ring opening of cyclohexene oxide with azide. This revealed the highest obtained space-time yield of 23.9 kgproduct  gCLEC -1  h-1  Lreactor volume -1 along with the highest achieved product enantiomeric excess [64%] for application in a packed-bed reactor. Additionally, lyophilization of those CLECs yielded a storage-stable HheG preparation that still retained 67% of initial activity (after lyophilization) after 6 months of storage at room temperature.

Strategies for overcoming protein and peptide instability in biodegradable drug delivery systems

The global pharmaceutical market has recently shifted its focus from small molecule drugs to peptide, protein, and nucleic acid drugs, which now comprise a majority of the top-selling pharmaceutical products on the market. Although these biologics often offer improved drug specificity, new mechanisms of action, and/or enhanced efficacy, they also present new challenges, including an increased potential for degradation and a need for frequent administration via more invasive administration routes, which can limit patient access, patient adherence, and ultimately the clinical impact of these drugs. Controlled-release systems have the potential to mitigate these challenges by offering superior control over in vivo drug levels, localizing these drugs to tissues of interest (e.g., tumors), and reducing administration frequency. Unfortunately, adapting controlled-release devices to release biologics has proven difficult due to the poor stability of biologics. In this review, we summarize the current state of controlled-release peptides and proteins, discuss existing techniques used to stabilize these drugs through encapsulation, storage, and in vivo release, and provide perspective on the most promising opportunities for the clinical translation of controlled-release peptides and proteins.

Sequential extraction of value-added bioproducts from three Chlorella strains using a drying-based combined disruption technique

In this study, the sequential extraction of the three types of biochemicals from microalgae is employed, which is a more realistic and practical solution for large-scale extraction of bioproducts. The drying, grinding, organic solvent treatment, and ultra-sonication were combined to disrupt cells and sequentially extract bioproducts from three microalgae strains, Chlorella sorokiniana IG-W-96, Chlorella sp. PG-96, and Chlorella vulgaris IG-R-96. As the drying is the most energy-intensive step in cell disruption and sequential extraction, the effect of this step on sequential extraction deeply explored. The results show that total ash-plus contents of biochemicals in freeze-dried samples (95.4 ± 2.8%, 89.3 ± 3.9%, and 77.5 ± 4.2 respectively) are higher than those in oven-dried samples (91.0 ± 2.8%, 89.5 ± 3.0%, 71.4 ± 4.8%, respectively) showing the superiority of freeze drying over oven drying merely for Chlorella vulgaris IG-R-96 (p-value = 0.003) and non-significant variation for Chlorella sorokiniana IG-W-96 (p-value = 0.085) and Chlorella sp. PG-96 (p-value = 0.466). Variation among biochemical contents of strains is due to the difference in cell wall strength confirmed by TEM imaging. The freeze-dried samples achieved higher lipid yields than oven-dried samples. The total carbohydrate yields followed the same pattern. The extraction yields of total protein were higher in freeze-dried samples than in oven-dried. Total mass balance revealed that drying-based sequential extraction of value-added bioproducts could better demonstrate the economic potential of sustainable and renewable algal feedstock than independent assays for each biochemical.

Efficacy of stem cell secretome loaded in hyaluronate sponge for topical treatment of psoriasis

Psoriasis vulgaris is an inflammatory disease characterized by distinctive skin lesions and dysregulated angiogenesis. Recent research uses stem cell secretion products (CM); a set of bioactive factors with therapeutic properties that regulate several cellular processes, including tissue repair and angiogenesis. The aim of this work was to evaluate the effect of CM of Wharton's gelatin MSC (hWJCM) in a treatment based on the bioactivation of a hyaluronic acid matrix (HA hWJCM) in a psoriasiform-like dermatitis (PD) mouse model. A preclinical study was conducted on PD mice. The effect of hWJCM, Clobetasol (Clob) gold standard, HA Ctrl, and HA hWJCM was tested topically evaluating severity of PD, mice weight as well as skin, liver, and spleen appearance. Treatment with either hWJCM, HA Ctrl or HA hWJCM, resulted in significant improvement of the PD phenotype. Moreover, treatment with HA hWJCM reduced the Psoriasis Area Severity Index (PASI), aberrant angiogenesis, and discomfort associated with the disease, leading to total recovery of body weight. We suggest that the topical application of HA hWJCM can be an effective noninvasive therapeutic solution for psoriasis, in addition to other skin diseases, laying the groundwork for future studies in human patients.

Development of Methamphetamine Conjugated Vaccine through Hapten Design: In Vitro and In Vivo Characterization

BACKGROUND

Methamphetamine (METH) substance-use disorder is an ever-growing global health issue with no effective treatment. Anti-METH vaccines are under investigation as an alternative to existing psychological interventions. This platform has made significant progress over past decades mainly in preclinical stages, and efforts to develop an anti-METH vaccine with a high antibody response are of utmost importance.

METHODOLOGY

A novel conjugated anti-METH vaccine was developed using METH HCl as the starting material for the design of hapten, a peptide linker consisting of five lysines and five glycines, and finally immunogenic carrier mannan, which is novel to this platform. All the chemical reaction steps were confirmed by several analytical techniques, and the immunogenicity of the developed vaccine was investigated in a mouse model.

RESULTS

Thin-layer chromatography and gas chromatography confirmed the reaction between METH and peptide linker. UV, NMR and color tests were used to confirm the presence of the aldehyde groups in oxidized mannan (OM). The final conjugated vaccine was confirmed by UV and LC-MS. The stability of mannan, the METH hapten, and the final vaccine was evaluated by UV and LC-MS and demonstrated satisfactory stability over 3 months in various storage conditions. Animal studies supported the immunogenicity of the novel vaccine.

CONCLUSIONS

We successfully developed and characterized a novel METH vaccine in vitro and in vivo. The present study findings are encouraging and will form the basis of further exploration to assess its effectiveness to prevent METH addiction in preclinical models.

Light-Assisted Drying for the Thermal Stabilization of Nucleic Acid Nanoparticles and Other Biologics

Cold-chain storage can be challenging and expensive for the transportation and storage of biologics, especially in low-resource settings. Nucleic acid nanoparticles (NANPs) are an example of new biological products that require refrigerated storage. Light-assisted drying (LAD) is a new processing technique to prepare biologics for anhydrous storage in a trehalose amorphous solid matrix at ambient temperatures. Small volume samples (10 μL) containing NANPs are irradiated with a 1064 nm laser to speed the evaporation of water and create an amorphous trehalose preservation matrix. In previous studies, samples were stored for 1 month at 4 °C or 20 °C without degradation. A FLIR SC655 mid-IR camera is used to record the temperature of samples during processing. The trehalose matrix was characterized using polarized light imaging to determine if crystallization occurred during processing or storage. Damage to LAD-processed NANPs was assessed after processing and storage using gel electrophoresis.

Stability and Function of Extracellular Vesicles Derived from Immortalized Human Corneal Stromal Stem Cells: A Proof of Concept Study

With significant advancement and development of extracellular vesicle (EV)-based therapies, there is a growing need to understand how their storage affects their physical and functional characteristics. EVs were isolated from the conditioned medium of a corneal stromal stem cell line (imCSSC) using Total Exosome isolation kit (TEI) and ultracentrifugation (UC) combined protocol. Purified EVs were stored at 4°C, - 80°C, room temperature (RT) after lyophilization with or without trehalose for 4 weeks. EVs stored at - 80°C and RT (lyophilization with trehalose) demonstrated a comparable morphology, while the freeze-dried samples without trehalose showed aggregation and degradation under a transmission electron microscope (TEM). Lyophilized samples without trehalose demonstrated a decreased particle concentration, recovery rate and protein concentration, which was remediated by the addition of trehalose. EVs stored at - 80℃ showed no change in the protein expression of CD9, CD63, and CD81. Regardless of the storage condition, all EV samples investigated reduced inflammation, as well as inhibited expression of fibrotic markers in vitro. Lyophilization of EVs with trehalose was a feasible storage method that retained the physical property and in vitro biological activities of EVs after 4 weeks of storage, while - 80°C offered the best retention of imCSSC-derived EV physical properties. For the first time, this data demonstrated a practical and translatable method for the storage of CSSC-derived EVs for clinical use.

The Application of Light-Assisted Drying to the Thermal Stabilization of Nucleic Acid Nanoparticles

Background: Cold-chain storage can be challenging and expensive for the transportation and storage of biologics, especially in low-resource settings. Nucleic acid nanoparticles (NANPs) are an example of new biological products that require refrigerated storage. Light-assisted drying (LAD) is a new processing technique to prepare biologics for anhydrous storage in a trehalose amorphous solid matrix at ambient temperatures. In this study, LAD was used to thermally stabilize four types of NANPs with differing structures and melting temperatures. Methods: Small volume samples (10 μL) containing NANPs were irradiated with a 1064 nm laser to speed the evaporation of water and create an amorphous trehalose preservation matrix. Samples were then stored for 1 month at 4°C or 20°C. A FLIR C655 mid-IR camera was used to record the temperature of samples during processing. The trehalose matrix was characterized using polarized light imaging (PLI) to determine if crystallization occurred during processing or storage. Damage to LAD-processed NANPs was assessed after processing and storage using gel electrophoresis. Results: Based on the end moisture content (EMC) as a function time and the thermal histories of samples, a LAD processing time of 30 min is sufficient to achieve low EMCs for the 10 μL samples used in this study. PLI demonstrates that the trehalose matrix was resistant to crystallization during processing and after storage at 4°C and at room temperature. The native-polyacrylamide gel electrophoresis results for DNA cubes, RNA cubes, and RNA rings indicate that the main structures of these NANPs were not damaged significantly after LAD processing and being stored at 4°C or at room temperature for 1 month. Conclusions: These preliminary studies indicate that LAD processing can stabilize NANPs for dry-state storage at room temperature, providing an alternative to refrigerated storage for these nanomedicine products.

Freezing-induced denaturation of myofibrillar proteins in frozen meat

Freezing is commonly used to extend the shelf life of meat and meat products but may impact the overall quality of those products by inducing structural changes in myofibrillar proteins (MPs) through denaturation, chemical modification, and encouraging protein aggregation. This review covers the effect of freezing on the denaturation of MPs in terms of the effects of ice crystallization on solute concentrations, cold denaturation, and protein oxidation. Freezing-induced denaturation of MPs begins with ice crystallization in extracellular spaces and changes in solute concentrations in the unfrozen water fraction. At typical temperatures for freezing meat (lower than -18 °C), cold denaturation of proteins occurs, accompanied by an alteration in their secondary and tertiary structure. Moreover, the disruption of muscle cells triggers the release of cellular enzymes, accelerating protein degradation and oxidation. To minimize severe deterioration during the freezing and frozen storage of meat, there is a vital need to use an appropriate freezing temperature below the glass transition temperature and to avoid temperature fluctuations during storage to prevent recrystallization. Such an understanding of MP denaturation can be applied to determine the optimum freezing conditions for meat products with highly retained sensory, nutritional, and functional qualities.

High-performance paper-based biocathode fabricated by screen-printing an improved mesoporous carbon ink and by oriented immobilization of bilirubin oxidase

In this study, the performance of a paper-based, screen-printed biofuel cell with mesoporous MgO-templated carbon (MgOC) electrodes was improved in two steps. First, a small amount of carboxymethyl cellulose (CMC) was added to the MgOC ink. Next, the cathode was modified with bilirubin prior to immobilizing the bilirubin oxidase (BOD). The CMC increased the accessibility of the mesopores of the MgOC, and subsequently, the performance of both the bioanode and biocathode. CMC also likely increased the stability of the electrodes. The pre-modification with bilirubin improved the orientation of the BOD, which facilitated direct electron transfer. With these two steps, an open circuit potential of 0.65 V, a maximal current density of 1.94 mA cm⁻², and a maximal power density of 465 μW cm⁻² was achieved with lactate oxidase as bioanode enzyme and lactate as fuel. This is one of the highest reported performances for a biofuel cell.

Properties of Human Gastric Lipase Produced by Plant Roots

The properties of recombinant human gastric lipase produced in Arabidopsis thaliana roots have been investigated with the goal of determining the potential of the enzyme. This enzyme is stably bound to roots and can be extracted using a buffer at pH 2.2. This enzyme retains over 75% of its activity after two weeks at room temperature when stored in a pH 2.2 buffer. Some of this activity loss was due to the adsorption of the enzyme to the surface of the container. There was no loss of lipase activity in dehydrated roots stored at room temperature for 27 months. The half-life of the enzyme was approximately 15 min when stored in solution at 60 °C whereas dried roots retained 90% lipase activity after one hour at 80 °C. In vitro binding assays using different root cell wall extracts suggested that the lipase was bound to pectin in the roots. Lipase released from the root powder hydrolyzed tributyrin. The high stability of the recombinant human gastric lipase makes this enzyme a good candidate to be tested as a catalyst, whether in solution or bound to roots.

Sample Processing Considerations for Protein Stability Studies of Low Concentration Biofluid Samples using Differential Scanning Calorimetry

Background:

The analysis of biofluid samples with low protein content (e.g., urine or saliva) can be challenging for downstream analysis methods with limited sensitivity. To circumvent this problem, sample processing methods are employed to increase the protein concentration in analyzed samples. However, for some techniques, like differential scanning calorimetry (DSC) that characterizes thermally-induced unfolding of biomolecules, sample processing must not affect native protein structure and stability.

Methods:

We evaluated centrifugal concentration and stirred cell ultrafiltration, two common methods of sample concentration characterized by a low risk of protein denaturation, with the goal of establishing a protocol for DSC analysis of low concentration biospecimens.

Results:

Our studies indicate that both methods can affect protein stability assessed by DSC and, even after optimization of several parameters, the obtained DSC profile (thermogram) suggested that sample processing affects the structure or intermolecular interactions of component proteins contributing to altered thermal stability detectable by DSC. We also found a relationship between changes in thermograms and low protein concentration, indicating that diluting biospecimens to concentrations below 0.1 mg/mL can perturb the intermolecular environment and affect the structure of proteins present in the solution.

Conclusions:

Dilution of samples below 0.1 mg/mL, as well as concentration of samples with low protein content, resulted in affected thermogram shapes suggesting changes in protein stability. This should be taken into account when concentrating dilute samples or employing techniques that lower the protein concentration (e.g., fractionation), when downstream applications include techniques, such as DSC, that require the preservation of native protein forms.

Hybrid Self-Assembling Nanoparticles Encapsulating Zoledronic Acid: A Strategy for Fostering Their Clinical Use

Self-assembling nanoparticles (SANPs) promise an effective delivery of bisphosphonates or microRNAs in the treatment of glioblastoma (GBM) and are obtained through the sequential mixing of four components immediately before use. The self-assembling approach facilitates technology transfer, but the complexity of the SANP preparation protocol raises significant concerns in the clinical setting due to the high risk of human errors during the procedure. In this work, it was hypothesized that the SANP preparation protocol could be simplified by using freeze-dried formulations. An in-depth thermodynamic study was conducted on solutions of different cryoprotectants, namely sucrose, mannitol and trehalose, to test their ability to stabilize the produced SANPs. In addition, the ability of SANPs to deliver drugs after lyophilization was assessed on selected formulations encapsulating zoledronic acid in vitro in the T98G GBM cell line and in vivo in an orthotopic mouse model. Results showed that, after lyophilization optimization, freeze-dried SANPs encapsulating zoledronic acid could retain their delivery ability, showing a significant inhibition of T98G cell growth both in vitro and in vivo. Overall, these results suggest that freeze-drying may help boost the industrial development of SANPs for the delivery of drugs to the brain.

Practical use of primary drying models in an industrial environment with limited availability of equipment sensors

In the pharmaceutical industry, lyophilization is typically adopted to extend long-time stability of valuable thermolabile medicines and vaccines. Primary drying is the most time-consuming and energy-intensive step of the entire process; thus, accelerating and optimizing the primary drying recipe is a key process development goal. To that purpose, mathematical models have been proposed and successfully validated. However, models typically require invasive experiments and/or sensors (e.g. product temperatures) for parameter estimation, which are rarely available in good manufacturing practice (GMP) environment. This represents a severe limitation when leveraging the model to transfer operation recipes across different facilities and for scale-up. In this study, we assess the possibility to exploit limited industrial data for model parameter estimation, namely pressure measurements and gravimetric tests, by defining a calibration protocol that is tested on two different pieces of equipment. Results are verified on a recently proposed model, and show that statistically meaningful estimates can be obtained without the need of product temperature measurements, and that model predictions and optimal inputs trajectories are comparable to those obtained from the model calibrated using the full set of temperature and pressure data.

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.

Physicochemical Properties and Whey Proteomes of Camel Milk Powders Produced by Different Concentration and Dehydration Processes

Camel milk powder production is an alternative to preserve the perishable milk for later-date consumption. However, the impacts of dehydration processes on bioactive compounds in camel milk are largely unknown. Hence, the present study attempted to compare the physicochemical properties and protein profiles of camel milk powders produced by different concentration and dehydration processes. Six camel milk powders were produced by freeze- and spray-drying methods in conjunction with two liquid concentration techniques, namely spray dewatering and reverse osmosis. The results of proteomic analysis showed that direct freeze-dried camel milk powder had the least changes in protein profile, followed by direct spray-dried powder. The camel milk powders that underwent concentration processes had more profound changes in their protein profiles. Among the bioactive proteins identified, lactotransferrin and oxidase/peroxidase had the most significant decreases in concentration following processing. On the contrary, glycosylation-dependent cell adhesion molecule 1, peptidoglycan recognition protein 1, and osteopontin increased in concentration. The results revealed that direct freeze drying was the most ideal method for preserving the bioactive proteins during camel milk powder production. However, the freeze-drying technique has cost and scalability constraints, and the current spray-drying technique needs improvement to better retain the bioactivity of camel milk during powder processing.