Development of a Single Vial Mass Flow Rate Monitor to Assess Pharmaceutical Freeze Drying Heterogeneity.

During pharmaceutical lyophilization processes, inter-vial drying heterogeneity remains a significant obstacle. Due to differences in heat and mass transfer based on vial position within the freeze drier, edge vials freeze differently, are typically warmer and dry faster than center vials. This vial position-dependent heterogeneity within the freeze dryer leads to tradeoffs during process development. During primary drying, process developers must be careful to avoid shelf temperatures that would result in overheating of edge vials causing the product sublimation interface temperature to rise above the critical (collapse) temperature. However, at lower shelf temperatures, center vials require longer to complete primary drying, risking collapse or melt-back due to incomplete drying. Both situations may result in poor product quality affecting drug stability, activity, and reconstitution times. We present a new approach for monitoring vial location-specific water vapor mass flow based on Tunable Diode Laser Absorption Spectroscopy (TDLAS). The single vial monitor enables measurement of the gas flow velocity, water vapor temperature, and gas concentration from the sublimating ice, enabling the calculation of the mass flow rate which can be used in combination with a heat and mass transfer model to determine vial heat transfer coefficients and product resistance to drying. These parameters can in turn be used for robust and rapid process development and control.

Comprehensive Optimization of a Freeze-Drying Process Achieving Enhanced Long-Term Stability and In Vivo Performance of Lyophilized mRNA-LNPs.

The success of mRNA vaccines against SARS-CoV-2 has prompted interest in mRNA-based pharmaceuticals due to their rapid production, adaptability, and safety. Despite these advantages, the inherent instability of mRNA and its rapid degradation in vivo underscores the need for an encapsulation system for the administration and delivery of RNA-based therapeutics. Lipid nanoparticles (LNPs) have proven the most robust and safest option for in vivo applications. However, the mid- to long-term storage of mRNA-LNPs still requires sub-zero temperatures along the entire chain of supply, highlighting the need to develop alternatives to improve mRNA vaccine stability under non-freezing conditions to facilitate logistics and distribution. Lyophilization presents itself as an effective alternative to prolong the shelf life of mRNA vaccines under refrigeration conditions, although a complex optimization of the process parameters is needed to maintain the integrity of the mRNA-LNPs. Recent studies have demonstrated the feasibility of freeze-drying LNPs, showing that lyophilized mRNA-LNPs retain activity and stability. However, long-term functional data remain limited. Herein, we focus on obtaining an optimized lyophilizable mRNA-LNP formulation through the careful selection of an optimal buffer and cryoprotectant and by tuning freeze-drying parameters. The results demonstrate that our optimized lyophilization process maintains LNP characteristics and functionality for over a year at refrigerated temperatures, offering a viable solution to the logistical hurdles of mRNA vaccine distribution.

Self-Nanoemulsifying/ Self-Assembled Cubic Nanoparticles Lyophilized Tablet: A Novel Biphasic Release Approach to Enhance the Bioavailability of a Lipophilic Drug.

This study aimed to prepare a combined self-nanoemulsifying and self-assembled cubic nanoparticles (SNE/SAC) lyophilized tablet eliciting biphasic release pattern escorted with enhanced bioavailability for drugs hampered with slow dissolution and poor absorption. The antimuscarinic Darifenacin hydrobromide (DRF) was selected as a model drug used to treat overactive bladder-associated nocturia. The DRF-SNE/SAC lyophilized tablet was prepared so that upon reconstitution a mixture of DRF-loaded cubic nanoparticles and nanoemulsion dispersion is obtained. The nanoemulsion portion is responsible for the fast release followed by controlled release of the remaining dose loaded in cubic nanoparticles. A comparative pharmacokinetic study adopting randomized crossover design in male albino rabbits versus marketed product Frequefenacine® tablet was performed. Half of the dose (52.05% ± 4.21%) was rapidly released in the first 4 h followed by sustained release of the remaining drug where (90.16% ± 8.85%) was released in 24 h. The tested system showed 2.45 folds higher % relative bioavailability and 1.57 folds higher Cmax with 1.62 longer residence time relative to reference product. The results endow the ability of the developed DRF-SNE/SAC lyophilized tablet to be considered as a propitious approach for the treatment of overactive bladder-associated nocturia without midnight dose administration.

Acoustic resonance technology and quality by design approach facilitate the development of the robust tetrandrine nano-delivery system.

The aim of this study was to develop a sufficiently robust tetrandrine (Tet) nano-delivery system using acoustic resonance (AR) technology and freeze-drying technology. This system can effectively improve the solubility and dissolution properties of Tet, along with high stability and scale-up adaptability. Firstly, 54 stabilizers were screened simultaneously in a high-throughput manner with the help of AR technology to fully explore the optimal prescription space of tetrandrine nanosuspension (Tet-NS). The Plackett-Burman design was used to screen for critical variables severely affecting the quality of Tet-NS. The Box-Behnken design was used to investigate and optimize critical variables to obtain optimal nanosuspensions. The optimal prescription was successfully scaled up by 100 times, which was the initial exploration of its commercial scale production. Solidification studies have shown that formulations with 2.44% fructose as the cryoprotectant have excellent redispersibility. Compared with pure Tet, Tet in Tet-NS showed a significant increase in solubility and dissolution rate in water. Fourier transform infrared (FT-IR) demonstrated that no significant interactions occurred between the drug and excipients in Tet-NS. Powder x-ray diffraction analysis (PXRD) indicated that some of the Tet transformed into amorphous state during the preparation process. In short-term stability study, Tet-NS successfully maintained its physical stability. In summary, under the guidance of the QbD concept, this study rapidly developed Tet-NS using acoustic resonance technology, which can effectively improve the solubility and dissolution properties of Tet. During the development of Tet-NS, AR technology has demonstrated high particle size reduction capability, the ability to process multiple sets of formulations in parallel, and excellent scale-up capability. Meanwhile, the method and concept of this study are not limited to Tet, but also applicable to other poorly water-soluble drugs.

Real-time estimation of bound water concentration during lyophilization with temperature-based state observers.

Lyophilization (aka freeze drying) has been shown to provide long-term stability for many crucial biotherapeutics, e.g., mRNA vaccines for COVID-19, allowing for higher storage temperature. The final stage of lyophilization, namely secondary drying, entails bound water removal via desorption, in which accurate prediction of bound water concentration is vital to ensuring the quality of the lyophilized product. This article proposes a novel technique for real-time estimation of the bound water concentration during secondary drying in lyophilization. A state observer is employed, which combines temperature measurement and mechanistic understanding of heat transfer and desorption kinetics, without requiring any online concentration measurement. Results from both simulations and experimental data show that the observer can accurately estimate the concentration of bound water in real time for all possible concentration levels, operating conditions, and measurement noise. This framework can also be applied for monitoring and control of the residual moisture in other desorption-related processes.

Microwave freeze-drying characteristics and crosslinking behavior of wheat starch-laurel acid complex.

This article investigates the effect of different microwave powers on the crosslinking behavior and microwave freeze-drying characteristics of wheat starch-lauroyl arginate complex during the microwave freeze-drying process. During microwave freeze-drying, as microwave power increased from 0.1 W/g to 0.9 W/g, the freeze-drying time of WS-LA was reduced by 50 %, while the uniformity of freeze-drying was not affected by its composition. In the research results obtained from DSC, Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), XRD, and SEM analyses, with the microwave power increased from 0.1 W/g to 0.9 W/g, the enthalpy value of the melting peak of the WS-LA (wheat starch-lauric acid) composite decreased from 1.15 J/g to 0.62 J/g. The full width at half maximum (FWHM) value increased from 25.6 to 30.79. The ratio of absorbance at 1022/995 cm-1 increased from 1.0111 to 1.0707. The recrystallization (RC) value decreased from 8.77 % to 0.07 %. Additionally, in the microstructure, the size of WS-LA composite particles decreased accordingly. The above findings indicated that the increase in microwave power during microwave freeze-drying had a negative impact on the formation of the WS-LA complex and the ordering of its structure in the sample.

A Comparison Analysis of Four Different Drying Treatments on the Volatile Organic Compounds of Gardenia Flowers.

The gardenia flower not only has extremely high ornamental value but also is an important source of natural food and spices, with a wide range of uses. To support the development of gardenia flower products, this study used headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) technology to compare and analyze the volatile organic compounds (VOCs) of fresh gardenia flower and those after using four different drying methods (vacuum freeze-drying (VFD), microwave drying (MD), hot-air drying (HAD), and vacuum drying (VD)). The results show that, in terms of shape, the VFD sample is almost identical to fresh gardenia flower, while the HAD, MD, and VD samples show significant changes in appearance with clear wrinkling; a total of 59 volatile organic compounds were detected in the gardenia flower, including 13 terpenes, 18 aldehydes, 4 esters, 8 ketones, 15 alcohols, and 1 sulfide. Principal component analysis (PCA), cluster analysis (CA), and partial least-squares regression analysis (PLS-DA) were performed on the obtained data, and the research found that different drying methods impact the VOCs of the gardenia flower. VFD or MD may be the most effective alternative to traditional sun-drying methods. Considering its drying efficiency and production cost, MD has the widest market prospects.

Point-of-care CRISPR-based Diagnostics with Premixed and Freeze-dried Reagents.

Molecular diagnostics by Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based detection have high diagnostic accuracy and attributes that are suitable for use at point-of-care settings such as fast turnaround times for results, convenient simple readouts, and no requirement of complicated instruments. However, the reactions can be cumbersome to perform at the point of care due to their many components and manual handling steps. Herein, we provide a step-by-step, optimized protocol for the robust detection of disease pathogens and genetic markers with recombinase-based isothermal amplification and CRISPR-based reagents, which are premixed and then freeze-dried in easily stored and ready-to-use formats. Premixed, freeze-dried reagents can be rehydrated for immediate use and retain high amplification and detection efficiencies. We also provide a troubleshooting guide for commonly found problems upon preparing and using premixed, freeze-dried reagents for CRISPR-based diagnostics, to make the detection platform more accessible to the wider diagnostic/genetic testing communities.

Evaluation of lyophilized bacteriophage cocktail efficiency against multidrug-resistant Salmonella in broiler chickens.

Currently, phage biocontrol is increasingly used as a green and natural technology for treating Salmonella and other infections, but phages exhibit instability and activity loss during storage. Therefore, in this study, the effects of lyophilization on the activity and stability of phage cocktails for the control of multidrug-resistant Salmonella in broiler chickens were determined. Eight serotypes of Salmonella were isolated and identified from broiler chicken farms, and bacteriophages against multidrug-resistant Salmonella enterica subsp. enterica serovar Kentucky, Salmonella enterica subsp. enterica serovar Typhimrium and Salmonella enterica subsp. enterica serovar Enteritidis were isolated. The bacteriophage cocktail was prepared and lyophilized, and it was subjected to in vitro and in vivo examinations. A reconstituted lyophilized bacteriophage cocktail was used for the oral treatment of chicks before and after challenge with multidrug-resistant S. Kentucky. The colonization of cecum by S. Kentucky was detected by using real-time PCR, and the serum levels of IgM, IgA and IL-4 and pathological changes in the different groups were detected. Three Caudovirales phages families were identified including Autographiviridae, Straboviridae and Drexlerviridae against multidrug-resistant S. Kentucky, S. Typhimrium and S. Enteritidis. The groups treated with the bacteriophage cocktail showed no clinical signs, no postmortem lesions, and a mortality rate of 0%, which improved the growth performance parameters. Additionally, the estimated serum levels of IgM, IgA and IL-4 were significantly greater in the bacteriophage cocktail-treated groups. Lyophilization effectively preserves the long-term storage stability of phages. Therefore, lyophilized bacteriophage cocktail therapy is a valuable approach for controlling multidrug-resistant Salmonella infections in broiler chickens.

The Use of Beetroot Juice as an Impregnating Solution to Change Volatile Compounds, Physical Properties and Influence the Kinetics of the Celery Drying Process.

The effect of different methods of drying celery root enriched with beet juice by vacuum impregnation (VI) was studied. The process of convection drying, vacuum drying and freeze drying was carried out. Compared to dried indigenous celery, dry impregnated tissue was characterized by lower values of dry matter, L* and b* color parameters, as well as higher values of water activity, density and a* color parameter. In addition, VI reduced the drying time. Forty Volatile Organic Compounds (VOCs) were found in celery, while fifty-one VOCs were found in the profile of celery with beetroot juice. The innovative method of vacuum impregnation made it possible to produce a new type of product with changed properties and a variable VOCs profile. The best fit of the drying process kinetics was achieved by using the logistic model. Increasing the temperature during convection drying resulted in shorter drying time, increased values of dry matter, reduced the water activity value and altered VOCs.

Exploring the Dissolution, Solid-state Properties, and Long-term Storage Stability of Cryoprotectant-free Fenbendazole Nanoparticles.

Fenbendazole is an antiparasitic drug widely used in veterinary medicine to treat parasitic infections caused in animals like cattle, horses, sheep, and dogs. Recently, it has been repositioned as a potential alternative for cancer treatment. However, it is a highly hydrophobic molecule (0.9 ug/mL), which can compromise its dissolution rate and absorption. Thus, this work aimed to apply a nanotechnological approach to improve drug solubility and dissolution performance. Fenbendazole nanoparticles stabilized by different poloxamers were obtained by lyophilization without cryoprotectants. The behavior of the drug in the solid state was analyzed by X-ray diffractometry, differential scanning calorimetry, and infrared spectroscopy. The nanosystems were also evaluated for solubility and dissolution rate. A long-term stability evaluation was performed for three years at room temperature. The yields of the lyophilization ranged between 75 and 81% for each lot. The nanoparticles showed a submicron size (< 340 nm) and a low polydispersity depending on the stabilizer. The physicochemical properties of the prepared systems indicated a remarkable amorphization of the drug, which influenced its solubility and dissolution performance. The drug dissolution from both the fresh and aged nanosystems was significantly higher than that of the raw drug. In particular, nanoparticles prepared with poloxamer 407 showed no significant modifications in their particle size in three years of storage. Physical stability studies indicated that the obtained systems prepared with P188, P237, and P407 suffered certain recrystallization during long storage at 25 °C. These findings confirm that selected poloxamers exhibited an important effect in formulating fenbendazole nanosystems with improved dissolution.

Development of a Stable Lyophilized Cyclophosphamide Monohydrate Formulation Using Non-Aqueous Solvents.

To ensure product stability, it is critical to maintain the monohydrate state of cyclophosphamide following lyophilization, as this is the most stable solid form of the Cyclophosphamide. On the other hand, because of their limited aqueous solubility and stability, non-aqueous solvents are preferred for determining the composition and stability of bulk solutions. Hence, the purpose of this study was to use non-aqueous solvents for determining the composition and stability of bulk solutions, and to shorten the lyophilization process by retaining the cyclophosphamide monohydrate. Furthermore, prior to selecting the solvent for the bulk solution consisting of 90:10 tertiary butyl alcohol (TBA) and acetonitrile (ACN), various factors were taken into account, including the freezing point, vapor pressure of solvents, solubility, and stability of cyclophosphamide monohydrate. The concentration of the bulk solution was adjusted to 200 mg/mL in order to optimize the fill volume, enhance sublimation rates at lower temperatures during primary drying, and eliminate the need for secondary drying. The differential scanning calorimetry (DSC) measurements of bulk solution were used to improve the lyophilization cycle. The lyophilization cycle opted was freezing at a temperature of -55 °C with annealing step at -22 °C by which the reconstitution time was significantly reduced. The drying was performed at below - 25 °C while maintaining a chamber pressure of 300 mTorr. The complete removal of non-aqueous solvents was achieved by retaining water within the system. The presence of cyclophosphamide monohydrate was confirmed using X-ray diffraction (XRD). The reduction of lyophilization process time was established by conducting mass transfer tests and evaluating the physicochemical properties of the pharmaceutical product. Using non-aqueous solvents for freeze-drying cyclophosphamide is a viable option, and this study provides significant knowledge for the advancement of future generic pharmaceuticals.

Hot air-assisted radio frequency drying of orange slices: Drying behavior and product quality.

This research aimed to assess the hot air-assisted radio frequency drying (HA-RFD) of orange slices to evaluate the possibility of producing high-quality dried orange slices and overcome the problem of the long drying time and the high energy consumption. The effect of electrode distance (60, 70, and 80 mm) and number of slices (1-3 slices; 4 mm thickness per slice) on the HA-RFD of orange slices was evaluated. Orange slices in three layers with a total thickness of 12 mm and an electrode gap of 70 mm were picked to dry the orange slices in the shortest time. The quality of orange slices dried with HA-RFD was compared with those of HA-dried (HAD) and freeze-dried (FD) samples. HA-RFD allowed a 67% decrease in the time of drying of the orange slices (from 1170 to 390 min) when compared to HAD. Total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, and color values were affected by the drying technique. HA-RFD showed higher TPC, TFC, and antioxidant activity than HAD. The FD samples showed the highest TPC (928 mg GAE/100 g dw), TFC (200 mg rutin/100 g dw), and antioxidant activity (67.58%). Moreover, the samples dried with HA-RFD resulted in the least color change in comparison to HAD and FD samples. Regarding vitamin C, FD samples were the best, followed by HA-RFD and HAD, respectively. Considering the final product quality, and the characteristics of drying techniques, especially drying time and drying rate, HA-RFD proved to be an alternative technique to the HAD for producing dried orange slices. PRACTICAL APPLICATION: HA-RFD was applied for the first time as an alternative technology to dry orange slices. The quality of orange samples dried by HA-RFD was compared with samples that dried by HAD and FD. The results indicated that the HA-RFD technique is a good method to dry orange slices by considering the drying characteristics and the final product quality.

Optimizing the secondary drying phase of a continuous Spin-Freeze Drying process: A semi-mechanistic modelling approach.

Over the past decade, continuous spin freeze-drying technology has emerged as a promising alternative to conventional batch freeze-drying, effectively addressing many of the latter's inherent disadvantages. Much of the focus during this period has been on controlling and optimizing the primary drying phase of this process. However, optimizing the secondary drying step is equally critical for the overall efficiency of the process. The primary aim of this study was to develop a comprehensive semi-mechanistic model for the secondary drying phase in continuous spin freeze-drying, accounting for the effects of process settings such as freezing rate and product temperature on desorption kinetics. Additionally, the study aimed to address discrepancies between conventional desorption models, typically applied in batch freeze-drying, and the observed data in this research. To achieve this, a residual moisture-dependent activation energy was introduced to improve the accuracy of the desorption model. Using NIR spectroscopy and IR-thermography, unknown model parameters could reliably be estimated using a simple and fast procedure. The calibrated model successfully predicted the final moisture content with an accuracy within 0.11% of the measured value under previously untested process conditions. Ultimately, the proposed semi-mechanistic model demonstrated its reliability in predicting the impact of new process conditions on both product temperature and residual moisture over time, enabling the development of a practical design space.

The influence of thermal radiation during microwave-assisted freeze-drying of pharmaceutical unit doses.

New drying technologies for biologicals have recently been developed to accelerate the time-consuming batch freeze-drying (BFD) process. Among others, microwave-assisted freeze-drying (MFD) has been suggested as a faster and more effective drying technology. In this study, MFD cycles with the microwave radiation switched on and off were performed to assess the contribution of the microwave radiation to drying acceleration. It was found that thermal radiation emitted by the drying chamber walls was predominantly accelerating the drying of monodose placebos rather than microwave radiation. The combination of ultra-low chamber pressure, high thermal heat transfer and a short primary-to-secondary phase transition reduces drying times by more than 80 % compared to conventional BFD. In a second step, a design of experiment approach was used to assess the effect of thermal radiation versus microwave radiation and their combination, together with dosage properties such as fill volume and excipient concentration upon drying rate. The outcome showed the importance of high fill volume and high excipient concentration for an effective microwave contribution to the drying rate. Nevertheless, the drying acceleration for small pharmaceutical dosages with restricted solutes was mainly driven by thermal radiation rather than 2.45 GHz microwave radiation. The inability of ice to convert microwave energy into heat hampers the potential use of microwave freeze-drying for single-dose vaccines.

Study of glutaraldehyde-treated crosslinking protocols for placental decellularized matrix sponges.

Extracellular matrix sponge plays a positive role in the wound healing process, but requires proper structural strength and biological properties. In order to solve the problem of lyophilized dissolution of placenta-derived sponge, glutaraldehyde was selected for use in the lyophilized crosslinking process to improve the necessary mechanical properties of the placental decellularization matrix sponge. In this work, the effects of three cross-linking methods of glutaraldehyde (Fumigation/Slurry/Soak) on the physical and biological characteristics of lyophilised sponges derived from placental acellular matrix was investigated. The results revealed that the sponges prepared by all three cross-linking methods exhibited excellent blood coagulation ability and stability. The fumigation cross-linked sponges had good mechanical properties of soft and elastic, and safe cytotoxicity, which were more compatible with the requirements of wound dressing. The slurry cross-linking process was uneven due to the stacked matrix materials, resulting in obvious cracks and easy to break when stretching. The soak crosslinking can obtain a higher degree of crosslinking, which leads to the poor antibacterial performance and the harder sponge scaffold with larger elastic modulus and smaller tensile ratio. In general, fumigation cross-linking is more suitable for the preparation of acellular sponge derived from placenta materials which can maintain basic mechanical properties and biological validity.

Development of a skeletal muscle sheet with direct reprogramming-induced myoblasts on a nanogel-cross-linked porous freeze-dried gel scaffold in a mouse gastroschisis model.

PURPOSE: In this study, we attempted to create skeletal muscle sheets made of directly converted myoblasts (dMBs) with a nanogel scaffold on a biosheet using a mouse gastroschisis model. METHODS: dMBs were prepared by the co-transfection of MYOD1 and MYCL into human fibroblasts. Silicon tubes were implanted under the skin of NOG/SCID mice, and biosheets were formed. The nanogel was a nanoscale hydrogel based on cholesterol-modified pullulan, and a NanoClip-FD gel was prepared by freeze-drying the nanogel. 7 mm in length was created in the abdominal wall of NOG/SCID mice as a mouse gastroschisis model. Matrigel or NanoCliP-FD gel seeded with dMBs was placed on the biosheet and implanted on the model mice. RESULTS: Fourteen days after surgery, dMBs with Matrigel showed a small amount of coarse aggregations of muscle-like cells. In contrast, dMBs with NanoCliP-FD gel showed multinucleated muscle-like cells, which were expressed as desmin and myogenin by fluorescent immunostaining. CONCLUSION: Nanogels have a porous structure and are useful as scaffolds for tissue regeneration by supplying oxygen and nutrients supply to the cells. Combining dMBs and nanogels on the biosheets resulted in the differentiation and engraftment of skeletal muscle, suggesting the possibility of developing skeletal muscle sheets derived from autologous cells and tissues.

Advantages of Spray Drying over Freeze Drying: A Comparative Analysis of Lonicera caerulea L. Juice Powders-Matrix Diversity and Bioactive Response.

The study investigated the impact of Lonicera caerulea L. juice matrix modification and drying techniques on powder characteristics. The evaluation encompassed phenolics (514.7-4388.7 mg/100 g dry matter), iridoids (up to 337.5 mg/100 g dry matter), antioxidant and antiglycation capacity, as well as anti-ageing properties of powders produced using maltodextrin, inulin, trehalose, and palatinose with a pioneering role as a carrier. Spray drying proved to be competitive with freeze drying for powder quality. Carrier application influenced the fruit powder properties. Trehalose protected the phenolics in the juice extract products, whereas maltodextrin showed protective effect in the juice powders. The concentrations of iridoids were influenced by the matrix type and drying technique. Antiglycation capacity was more affected by the carrier type in juice powders than in extract products. However, with carrier addition, the latter showed approximately 12-fold higher selectivity for acetylcholinesterase than other samples. Understanding the interplay between matrix composition, drying techniques, and powder properties provides insights for the development of plant-based products with tailored attributes, including potential health-linked properties.

The Impact of Drying Methods on the Quality of Blanched Yellow Mealworm (Tenebrio molitor L.) Larvae.

The growing world population necessitates the implementation of appropriate processing technologies for edible insects. The objective of this study was to examine the impact of distinct drying techniques, including convective drying at 70 °C (70CD) and 90 °C (90CD) and freeze-drying (FD), on the drying kinetics, physical characteristics (water activity, color), chemical characteristics (chemical composition, amino acid profile, oil properties, total polyphenol content and antioxidant activity, mineral composition, FTIR), and presence of hazards (allergens, microorganisms) of blanched yellow mealworm larvae. The freeze-drying process results in greater lightness and reduced moisture content and water activity. The study demonstrated that the freeze-dried insects exhibited lower contents of protein and essential amino acids as compared to the convective-dried insects. The lowest content of total polyphenols was found in the freeze-dried yellow mealworm larvae; however, the highest antioxidant activity was determined for those insects. Although the oil isolated from the freeze-dried insects exhibited the lowest acid and peroxide values, it proved to have the lowest PUFA content and oxidative stability. All the samples met the microbiological criteria for dried insects. The results of the study demonstrate that a high temperature during the CD method does not result in the anticipated undesirable changes. It appears that freeze-drying is not the optimal method for preserving the nutritional value of insects, particularly with regard to the quality of protein and oil.

Minimally invasive soft tissue repair using shrunken scaffolds.

The minimally invasive injection of tissue engineering scaffolds is of interest as it requires a smaller incision and quickens recovery. However, the engineering of scaffolds capable of injection remains a challenge. Here, we report on a shrunken scaffold inspired by the shrinking of puffed food in a humid environment. A scaffold is freeze-dried to remove water then placed in a humid atmosphere. The humidity causes the dry scaffold to shrink by up to 90%. In addition, the humidity treatment reduces the scaffolds modulus minimizing the foreign body response after implantation. The scaffolds can rapidly swell into their original size and shape after application. A tool for the delivery of the minimally invasive scaffolds is developed and we demonstrate the potential for minimally invasive delivery using this shrinking technique.