We have isolated an intestinal probiotic strain, Pediococcus acidilactici HRQ-1. To improve its gastrointestinal fluid tolerance, transportation and storage stability, and slow-release properties, we employed the extrusion method to prepare the microcapsules with P. acidilactici HRQ-1 as the core material and sodium alginate and chitosan as the wall material. The optimal conditions for preparing the microcapsules were determined by single factor and orthogonal tests, and the optimal ratio was determined by taking the embedding rate, survival rate, storage stability, gastrointestinal fluid tolerance, and release rate as the evaluation indexes. The results showed that under the optimal embedding conditions, the embedding rate reached (89.60±0.02)%. Under the optimal formula of freeze-drying protective agent, the freeze-drying survival rate reached (76.42±0.13)%, and the average size of the microcapsules produced was (1.16±0.03) mm. The continuous gastrointestinal fluid simulation experiments confirmed that the microcapsules ensured the viable bacterial count and can slowly release bacteria in the intestinal fluid. The curve of the viable bacterial count during storage at 4 ℃ and room temperature indicated that the prepared microcapsules achieved strains' live number protection. The formula and preparation process of P. acidilactici microcapsules may provide a technological reserve for the preparation of more live bacterial drugs in the future.
Pediococcus acidilactici/chemistry* ; Probiotics/chemistry* ; Capsules/chemistry* ; Alginates/chemistry* ; Chitosan/chemistry* ; Drug Compounding/methods* ; Glucuronic Acid/chemistry* ; Hexuronic Acids/chemistry* ; Freeze Drying

Vaccination is a crucial strategy for the prevention and control of infectious diseases. Virus-like particles (VLPs), composed of structural proteins, have garnered significant attention as a novel type of vaccine due to their excellent safety and immunogenicity. However, similar to most vaccine antigens, VLPs exhibit insufficient thermal stability, which not only restricts the widespread application of vaccines but also increases the risk of vaccine inactivation. This study aims to enhance the stability and shelf life of VLPs derived from type A foot-and-mouth disease virus (FMDV) by employing vacuum freeze-drying technology. The optimal lyoprotectant formulation was determined through single-factor and combinatorial screening. Subsequently, the correlation between the immunogenicity of the freeze-dried vaccine and the content of FMDV VLPs was evaluated via a mouse model. The stability of FMDV VLPs before and after freeze-drying was further assessed by storing them at 4, 25, and 37 ℃ for varying time periods. Results indicated that the lyoprotectant formulation No.1, composed of 7.5% trehalose, 0.1% Tween 80, 50 mmol/L glycine, 1% sodium glutamate, and 3% polyvinylpyrrolidone (PVP), effectively preserved the content of FMDV VLPs during the vacuum freeze-drying process. The immunization trial in mice revealed that the levels of specific antibodies, immunoglobulin G1 (IgG1), interleukin-4 (IL-4), and neutralizing antibodies induced by freeze-dried FMDV VLPs were comparable to those induced by non-freeze-dried FMDV VLPs. The heat treatment results showed that the storage periods of freeze-dried FMDV VLPs at 4, 25, and 37 ℃ were significantly longer than those of non-freeze-dried FMDV VLPs. In conclusion, the selected lyoprotectant formulation effectively improved the stability of FMDV VLPs vaccines. This study provides valuable insights for enhancing the stability of novel subunit vaccines.
Freeze Drying/methods* ; Animals ; Foot-and-Mouth Disease Virus/immunology* ; Mice ; Vaccines, Virus-Like Particle/chemistry* ; Foot-and-Mouth Disease/immunology* ; Vacuum ; Drug Stability ; Mice, Inbred BALB C ; Viral Vaccines/immunology*

This study aims to optimize the process for preparing chitosan-based ultrasound-coupled hydrogel pads and investigate their application potential in ultrasonography. Chitosan, 2-acrylamido-2-methylpropanesulfonic acid, and N-isopropylacrylamide were used as the main materials to prepare chitosan-based ultrasound-coupled hydrogel pads. The free-radical polymerization conditions were optimized by a three-factor, three-level orthogonal test with the tensile strength and ultrasound image quality of the hydrogel pads as evaluation indicators. The optimal prescription was selected by optimizing three factors of raw material ratio, polymerization temperature, and freeze-drying time. The structure and performance of the hydrogel pads were characterized by a scanning electron microscope, a universal testing machine, and an ultrasonic diagnostic instrument. The results showed that the optimal prescription was as follows: the chitosan: 2-acrylamide-2-methylpropanesulfonic acid: N-isopropylacrylamide ratio of 2:0.55:17.27, the polymerization temperature of 25 ℃, and the freeze-drying time of 48 h. The ultrasonically-coupled hydrogel pads prepared under these conditions were transparent, with a porous structure, good adhesion, and high tensile strength. The hydrogel pads had good swelling properties and the swelling degree decreased slowly on day 10. The quality of the ultrasound images obtained via chitosan-based hydrogel pads was not significantly different from that obtained via medical ultrasound coupling agent. In this study, we analyzed the effects of different preparation processes on the gel formation of chitosan-based ultrasound-coupled hydrogel pads. The hydrogel pads were transparent and mild and non-irritating to the human body, serving as an ultrasound transmission material for ultrasonography.
Chitosan/chemistry* ; Hydrogels/chemistry* ; Acrylamides/chemistry* ; Ultrasonography ; Polymerization ; Sulfonic Acids/chemistry* ; Alkanesulfonates/chemistry* ; Tensile Strength ; Freeze Drying ; Temperature

Bioactive glass (BG) has been widely used in the preparation of artificial bone scaffolds due to its excellent biological properties and non-cytotoxicity, which can promote bone and soft tissue regeneration. However, due to the brittleness, poor mechanical strength, easy agglomeration and uncontrollable structure of glass material, its application in various fields is limited. In this regard, most current researches mainly focus on mixing BG with organic or inorganic materials by freeze-drying method, sol-gel method, etc., to improve its mechanical properties and brittleness, so as to increase its clinical application and expand its application field. This review introduces the combination of BG with natural organic materials, metallic materials and non-metallic materials, and demonstrates the latest technology and future prospects of BG composite materials through the development of scaffolds, injectable fillers, membranes, hydrogels and coatings. The previous studies show that the addition of BG improves the mechanical properties, biological activity and regeneration potential of the composites, and broadens the application of BG in the field of bone tissue engineering. By reviewing the recent BG researches on bone regeneration, the research potential of new materials is demonstrated, in order to provide a reference for future related research.
Bone Regeneration ; Bone and Bones ; Freeze Drying ; Glass ; Hydrogels

The freeze-drying technique, characterized by low-temperature processing, is especially suitable for sensitive volatile oils with thermal instability. However, there are few studies focusing on the retention of volatile oils in the processing of freeze-dried preparations. This study evaluated the effects of different addition methods(adsorption, emulsification, solid dispersion, and inclusion) on the retention rate of the main components in peppermint oil, aiming to explore the application feasibility of freeze-dried preparations of volatile oils. Firstly, the addition method was determined based on the retention rates of menthol in four freeze-dried preparations. Secondly, an orthogonal test was designed to optimize the preparation process based on the characteristics of the preferred addition method. The results showed that the most suitable preparation form of peppermint oil was inclusion with beta-cyclodextrin(β-CD), and the retention rate of menthol in freeze-drying was 86.36%. According to the two-step preparation process of inclusion and freeze-drying, we introduced the product of inclusion rate and retention rate, i.e., comprehensive retention rate, to determine the optimum processing parameters. The results showed that β-CD/oil ratio of 7∶1, inclusion temperature of 40 ℃, and inclusion time of 2 h were the optimum processing parameters. The product prepared with these parameter had the comprehensive retention rate of 68.41%, retention rate of 92.53%, and inclusion rate of 73.93%. The inclusion compound was white powder with significantly increased solubility. The pre-paration process based on cyclodextrin inclusion in this study is stable and reliable and provides a new idea for ensuring the efficacy and stability of volatile components in freeze-dried preparations.
Cyclodextrins ; Freeze Drying ; Mentha piperita ; Oils, Volatile ; Plant Oils ; Solubility ; Technology

OBJECTIVES: The purpose of this study is to shorten the decellularization time of trachea by using combination of physical, chemical, and enzymatic techniques. METHODS: Approximately 3.5-cm-long tracheal segments from 42 New Zealand rabbits (3.5±0.5 kg) were separated into seven groups according to decellularization protocols. After decellularization, cellular regions, matrix and strength and endurance of the scaffold were followed up. RESULTS: DNA content in all groups was measured under 50 ng/mg and there was no significant difference for the glycosaminoglycan content between group 3 (lyophilization+deoxycholic acid+de-oxyribonuclease method) and control group (P=0.46). None of the decellularized groups was different than the normal trachea in tensile stress values (P>0.05). Glucose consumption and lactic acid levels measured from supernatants of all decellularized groups were close to group with cells only (76 mg/dL and 53 mg/L). CONCLUSION: Using combination methods may reduce exposure to chemicals, prevent the excessive influence of the matrix, and shorten the decellularization time.
Deoxycholic Acid ; DNA ; Freeze Drying ; Glucose ; Lactic Acid ; Rabbits ; Tissue Engineering ; Trachea

The aim of this paper was to compare the influence of freeze-drying and sun-drying on six main nucleosides and nucleobases of Cordyceps sinensis by HPLC. Hypoxanthine,xanthine,uridine,inosine,guanosine and adenosine were reference substances. HPLC analysis was performed on a GL Inertsustain AQ-C_(18) column( 4. 6 mm×250 mm,5 μm),with mobile phase consisting of water( A)-acetonitrile( B) at the flow rate of 1. 0 mL·min~(-1)( 0-10 min,0-1% B; 10-65 min,1%-3% B). The detection wavelength was 260 nm,the column temperature was controlled at 30 ℃,and the injection volume was 5 μL. The linear ranges of hypoxanthine,xanthine,uridine,inosine,guanosine and adenosine were 1. 025-20. 50( r = 0. 999 8),0. 545-10. 90( r = 0. 999 9),4. 051-81. 02( r = 0. 999 8),4. 044-80. 88( r= 0. 999 9),2. 075-41. 50( r= 0. 999 9),4. 032-80. 64( r = 0. 999 9) mg·L~(-1),respectively. The average recoveries of them( n = 6)were as follows: 102. 3%( RSD 2. 1%),101. 1%( RSD 2. 4%),97. 80%( RSD 1. 7%),101. 8%( RSD 1. 8%),98. 90%( RSD2. 0%) and 98. 10%( RSD 1. 4%),respectively. Each sample was processed by freeze-drying and sun-drying so as to compare the difference between the two drying methods. The contents of six index ingredients were significantly different between freeze-drying and sun-drying sample of C. sinensis. The total contents of six index ingredients in sun-drying sample were higher than that in the corresponding freeze-drying sample. This research results provide the scientific basis for the drying methods and quality evaluation of C. sinensis.
Chromatography, High Pressure Liquid ; Cordyceps ; chemistry ; Desiccation ; Freeze Drying ; Nucleosides ; analysis

Cell freeze-drying can be divided into the freezing and drying processes. Mechanical damage caused by ice crystals and damage from solute during freezing shall not be ignored and lyoprotectants are commonly used to reduce those damages on cells. In order to study the mechanism of lyoprotectants to protect cells and determine an optimal lyoprotectant formula, the thermophysical properties and percentage of unfrozen water of different lyoprotectants in freezing were investigated with differential scanning calorimeter (DSC). The survival rate indicated by trypan blue exclusion test and cell-attachment rate after 24 h using different lyoprotectants to freeze hepatoma Hep-G cells were measured after cell cryopreservation. The results show that 40% (W/V) PVP + 10% (V/V) glycerol + 15% (V/V) fetal bovine serum + 20% (W/V) trehalose formula of lyoprotectant demonstrate the best effect in protecting cells during freezing, for cell-attachment rate after 24 h is 44.56% ± 2.73%. In conclusion, the formula of lyoprotectant mentioned above can effectively protect cells.
Calorimetry, Differential Scanning ; Cryopreservation ; Cryoprotective Agents ; chemistry ; Freeze Drying ; Freezing ; Hep G2 Cells ; Humans ; Trehalose ; chemistry

To study the effects of fresh-cut drying methods on the appearance and internal components of Panax notoginseng, and explore the feasibility of fresh-cut drying methods of P. notoginseng, so as to provide more effective processing methods for the production of P. notoginseng slices and Chinese patent medicines. In this study, we have compared the effects of 6 different drying methods on drying time, drying rate, density, appearance and internal components of P. notoginseng roots. It takes about 453 h to dry by whole-root drying in the sun, with a long constant speed period and a slow drying rate, the time of whole-root drying at 50 ℃ was shortened by 61.6% compared with whole-root drying in the sun, which resulted in the decrease of density and poor appearance of the medicinal material with hollow and crack appeared in the xylem, while the drying time of fresh-cut drying method was reduced by 61.82% to 91.58% and the drying rate increased greatly, due to the relatively slow drying process in the sun or in the shade after fresh-cut, salting-out and whitening appeared on the surface, and the internal components were all decreased to some extent. The drying time of fresh-cut drying at 50 ℃ was 91.58% and 68.83% shorter than that of whole-root drying in the sun and at 50 ℃, respectively. When drying at 50 ℃ after fresh-cut, the appearance and content of internal components of the medicinal materials were better, the appearance was yellowish green, the cut sections were clear with uniform pore distribution, and the content of saponin components was increased by 7.24% compared with that of the whole-root drying at 50 ℃, When drying at 40 ℃, the surface of slices has salting-out and whitening spots, and the loss of dencichine and total sugar was large, but at 60 ℃, this high temperature made the rate of dehydration of slices was extremely fast, which led to severe cracking and fragmentation, and the loss of total sugar and alcohol extract was large. By vacuum freeze drying after fresh-cut, the structure of medicinal materials slices was loose, the density was greatly reduced, and the appearance was different from those recorded in traditional books. The contents of total saponin components and dencichine were increased by 16.51% and 22.54%, respectively, compared with traditional whole-root drying. The fresh-cut process method is feasible in the production of P. notoginseng slices. In production, it is recommended that drying at 50 ℃ after fresh-cut can make the medicinal materials better in appearance and content of internal components, which is convenient for the subsequent processing and industrial feeding extraction. For the purpose of internal contents, it is better to adopt freeze-drying after fresh-cut processing method.
Desiccation ; Drugs, Chinese Herbal ; standards ; Freeze Drying ; Panax notoginseng ; Plant Roots ; Quality Control ; Saponins ; analysis

BACKGROUND: Nowadays, production of nanocomposite scaffolds based on natural biopolymer, bioceramic, and metal ions is a growing field of research due to the potential for bone tissue engineering applications. METHODS: In this study, a nanocomposite scaffold for bone tissue engineering was successfully prepared using collagen (COL), beta-tricalcium phosphate (β-TCP) and strontium oxide (SrO). A composition of β-TCP (4.9 g) was prepared by doping with SrO (0.05 g). Biocompatible porous nanocomposite scaffolds were prepared by freeze-drying in different formulations [COL, COL/β-TCP (1:2 w/w), and COL/β-TCP-Sr (1:2 w/w)] to be used as a provisional matrix or scaffold for bone tissue engineering. The nanoparticles were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy and energy dispersive spectroscopy. Moreover, the prepared scaffolds were characterized by physicochemical properties, such as porosity, swelling ratio, biodegradation, mechanical properties, and biomineralization. RESULTS: All the scaffolds had a microporous structure with high porosity (~ 95–99%) and appropriate pore size (100–200 µm). COL/β-TCP-Sr scaffolds had the compressive modulus (213.44 ± 0.47 kPa) higher than that of COL/β-TCP (33.14 ± 1.77 kPa). In vitro cytocompatibility, cell attachment and alkaline phosphatase (ALP) activity studies performed using rat bone marrow mesenchymal stem cells. Addition of β-TCP-Sr to collagen scaffolds increased ALP activity by 1.33–1.79 and 2.92–4.57 folds after 7 and 14 days of culture, respectively. CONCLUSION: In summary, it was found that the incorporation of Sr into the collagen-β-TCP scaffolds has a great potential for bone tissue engineering applications.
Alkaline Phosphatase ; Animals ; Biopolymers ; Bone and Bones ; Bone Marrow ; Collagen ; Fourier Analysis ; Freeze Drying ; In Vitro Techniques ; Ions ; Mesenchymal Stromal Cells ; Nanocomposites ; Nanoparticles ; Porosity ; Rats ; Spectrum Analysis ; Strontium ; X-Ray Diffraction