查找使用阿拉丁产品的科研文献

ICG@ZIF@HA Nanoparticles and GO-Loaded Freeze-Drying Microneedles Mediated PDT/PTT Dual-Modal Phototherapeutic for Efficient Bacterial Biofilm Elimination

Yanyan Zheng,Yueyue Xie,Xu Dong,Shulin Shen,Gensuo Zheng,Jiaqi Weng,Qinying Yan

Biofilms, which are dense bacterial aggregates that form protective adhesion layers on surfaces, are associated with chronic wound infections, severe acne, and various other bacterial infection sites. However, the increasing antibiotic resistance of bacteria within biofilms and the limited penetration capacity of conventional treatments pose significant therapeutic challenges. To address these issues, we engineered a freeze-drying microneedle system integrating indocyanine green-loaded ZIF-8/hyaluronic acid nanoparticles (ICG@ZIF@HA NPs) and graphene oxide (GO) for dual-modal phototherapy. Notably, the microneedles demonstrated robust mechanical strength, enabling penetration through 140 μm-thick Staphylococcus aureus biofilms. Subsequently, the disruption of the biofilm’s structural integrity facilitated the release of ICG@ZIF@HA NPs from the microneedle tips into deeper biofilm regions. Moreover, the nanoparticles exhibited pH-triggered release kinetics, with over 80% of ICG released at pH 5.5 within 2 h, and generated reactive oxygen species (ROS) under 808 nm near-infrared (NIR) irradiation. Meanwhile, the GO in the backing provided localized hyperthermia, reaching 55 °C within 500 s under NIR exposure. By combining ROS generation and bacterial membrane disruption, the microneedle system achieved a synergistic antimicrobial effect, effectively inhibiting bacterial growth and eliminating biofilms under NIR irradiation. Thus, this study establishes a robust foundation for integrating antimicrobial therapy with microneedle technology, offering a safer and more efficient strategy for biofilm eradication.

Synthesis of Hydrophobically Associating Polymers with Natural Product Structures by a One-Pot Method – Comparison of Ethanol Treatment and Freeze-Drying

Chunhui Wang,Kuan Ji,Weina Jia,Shuai Shao,Yumeng Liu,Xiaohui Jiang,Liangmin Yu

Graphical The HAPAM containing natural product structure was synthesized by the innovative one-pot method in a soap-free aqueous system and the product was treated with ethanol elution and freeze-drying for the second time. The thermal degradation, micromorphology, temperature and salinity tolerance and other related properties were tested and analyzed. Polyacrylamide-based hydrophobically associating polymers (HAPAM) containing capsaicin derivatives and itaconic acid with acrylamide (AM) and methacrylic acid (MAA) as the main bodies, and N-vinylpyrrolidone (NVP) as the functional monomer are prepared by a one-pot synthesis of the soap-free emulsion polymerization process. The structure is characterized by fourier transform infrared (FTIR) and 1 H nuclear magnetic resonance ( 1 H NMR), and thermal gravimetric analyzer (TGA) explores thermal stability. For achieving proper purification, excellent preservation and convenient transportation of the polymer and to advance its practical engineering applications, two different treatments, namely ethanol washout and freeze-drying, are carried out and compared. The surface morphology observation manifests that the freeze-drying products (DHPAM) better protect the three-dimensional cross-linked network structure formed by various supramolecular forces such as hydrophobic association, electrostatic and hydrogen bonding inside the polymer than the ethanol washout products (EHPAM), which well explains why DHPAM has lower critical association concentration (CAC), greater resistance to high temperature and high salt, and better corrosion inhibition performance than EHPAM. It is significant for strengthening the application of polymers in related fields, especially oil and gas extraction.

Surface-tension-free fabrication to minimize defects in cobalt-silica membranes via the freeze-drying technique for H2 separation at high temperatures

Tanzila Anjum,Hammad Saulat,Gianni Olguin,David K. Wang,Xiaozhen Zhang,Xiaonan Kou,Xian Yin,Asim Laeeq Khan,Guozhao Ji

Hydrogen is a promising substitute for fossil fuels because it has a high calorific value and is eco-friendly. Cobalt-doped silica membranes, suitable for separating hydrogen from other larger molecular gases at high temperatures, are commonly fabricated by the dip-coating method, followed by evaporation drying and calcination. However, these membranes suffer from defects within selective layers, reducing the separation efficiency by allowing non-selective permeation. These defects can be ascribed to surface tension effects during evaporation drying, where the imbalance between liquid-phase cohesion and adhesive interactions with the solid substrate leads to non-uniform solvent evaporation, resulting in stress accumulation, capillary forces, and eventual structural imperfections such as cracks and pinholes. In this study, a novel freeze-drying technique is introduced to minimize defects in cobalt-silica membranes by avoiding surface tension. For this purpose, α-alumina substrates were selected, and a zeolite interlayer was formed on the substrate, which provided the pore size transition to fabricate cobalt-doped silica separation membranes. The structural and morphological analyses confirm the effectiveness of the freeze-drying technique, revealing a higher silica condensation, increased amorphous character, smoother surfaces, homogeneous cobalt dispersion with the presence of Co3+, and uniform, smaller pore sizes, outperforming the evaporation-dried technique in terms of separation efficiency and indicating fewer defects. At 500 °C, the freeze-dried membrane showed almost three times higher H2/N2 and H2/CO2 selectivity than the conventional evaporation-dried membrane. The novel freeze-drying technique showed a promising potential for H2 separation applications at high temperatures.

Effects of Spray Drying and Freeze Drying on Physicochemical Properties, Antioxidant and ACE Inhibitory Activities of Bighead Carp (Aristichthys nobilis) Skin Hydrolysates

Ye Dong,Wen Yan,Yi-Qi Zhang

The physicochemical, structural properties, antioxidant, and angiotensin I-converting enzyme (ACE) inhibitory activities of fish skin protein hydrolysate (SPH) that were freeze-dried (SPH-FD) and spray-dried (SPH-SD) were investigated. SPH-SD showed abundant volatile compounds, higher DPPH radical scavenging activity and ferrous iron chelating activity than SPH-FD, while the ABTS radical scavenging activity and ACE inhibitory activity were not influenced by the drying method. Amino acid compositions showed a higher proportion of proline and hydroxyproline residues in SPH-FD. The major molecular weights were both distributed below 1000 Da. SPH-SD had spherical structures, while SPH-FD had glass shard-like structures. The results indicated that the drying method could affect the physicochemical properties of hydrolysates, and SPH-SD showed potential prospects in developing functional fortified foods.Keywords:fish skin hydrolysate;freeze drying;spray drying;antioxidant;ACE inhibitory activity

Comparative Evaluation of Physicochemical Properties, Microstructure, and Antioxidant Activity of Jujube Polysaccharides Subjected to Hot Air, Infrared, Radio Frequency, and Freeze Drying

Bengang Wu,Chengcheng Qiu,Yiting Guo,Chunhong Zhang,Dan Li,Kun Gao,Yuanjin Ma,Haile Ma

In this study, we used four drying methods (hot air, freezing, infrared, and radio frequency) to dry fresh jujube and its polysaccharide extracts by a two-step drying method, and the effects of the drying methods on the physical and chemical properties, structural properties, and antioxidant activity of jujube polysaccharides were studied. The results showed significant differences in the yield, drying time, monosaccharide content, molecular weight, apparent viscosity, thermal stability, and microstructure of the polysaccharides treated under the different drying methods. In contrast, no significant differences in the monosaccharide composition and functional groups of the polysaccharide samples obtained from the different drying methods were observed. Among all the tested methods, the freeze-drying extraction rate was the highest, reaching 4.52 ± 0.19%, while its drying time was the longest. Although the extraction rate of radio frequency drying was only 3.55 ± 0.21%, the drying time was the shortest, compared with hot air drying, the drying time was reduced by 76.67–83.29%, and the obtained polysaccharides exerted good antioxidant activity. Therefore, radio frequency drying is a potential polysaccharide extraction and drying technique, and this study can provide a theoretical basis for its industrial production.Keywords:jujube polysaccharide;drying methods;physicochemical property;structural characteristic;antioxidant activity

Preparation of sodium alginate antibacterial porous composite pads embedded with centrifugally spun nanofibers by freeze-drying and recasting for active food packaging

Hao Wang,Mengjiao Li,Rui Ren,Zhennan Gao,Lingna Meng,Ziyi Li,Chuanai Cao

In this study, nanofibers composed of ethyl cellulose (EC)/polyethylene oxide (PEO) impregnated with tea polyphenol (TP) were fabricated by the centrifugal spinning method. Subsequently, these nanofibers were incorporated into sodium alginate (SA) to generate porous composite pads with varying fiber contents. The porous composite pads were comprehensively characterized. The findings indicate that the nanofiber structure of the porous composite pads is maintained, the porosity of the porous composite pads ranges from 16 % to 28 %, the water vapor transfer rate decreases as the fiber addition increases, and the thermal stability improves. Additionally, the pads demonstrated enhanced slow-release characteristics, and the cumulative TP release reached 70 % to 81.44 % within 120 h. All the porous composite pads could effectively inhibit the growth of Staphylococcus aureus and Escherichia coli , and the inhibition rates of the two bacteria were 99.69 % and 99.54 % respectively, highlighting their potential application in active food packaging.

Comparison of Freeze-drying and Gradient Dehydration Treatment on X-ray Imaging for Three-dimensional Reconstruction of Early Human Embryonic Brain Samples

Yao Yangqianbo,Hao Wenjie,Wu Shengju,He Qizhi,Xiao Tiqiao,Zhang Zhijun

Freeze-drying synthesis of three-dimensional porous LiFePO4 modified with well-dispersed nitrogen-doped carbon nanotubes for high-performance lithium-ion batteries

Xiaofeng Tu,Yingke Zhou,Yijie Song

The three-dimensional porous LiFePO 4 modified with uniformly dispersed nitrogen-doped carbon nanotubes has been successfully prepared by a freeze-drying method. The morphology and structure of the porous composites are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the electrochemical performances are evaluated using the constant current charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The nitrogen-doped carbon nanotubes are uniformly dispersed inside the porous LiFePO 4 to construct a superior three-dimensional conductive network, which remarkably increases the electronic conductivity and accelerates the diffusion of lithium ion. The porous composite displays high specific capacity, good rate capability and excellent cycling stability, rendering it a promising positive electrode material for high-performance lithium-ion batteries.

Effects of High Hydrostatic Pressure Combined with Vacuum-Freeze Drying on the Aroma-Active Compounds in Blended Pumpkin, Mango, and Jujube Juice

Lin Yuan,Xujuan Liang,Xin Pan,Fei Lao,Yong Shi,Jihong Wu

A combination process of completely non-thermal processing methods involving high hydrostatic pressure (HHP) and vacuum-freeze drying (VFD) for producing a new snack from fruit and vegetable blends was developed, and the effect of the process on flavor quality was investigated. The HHP–VFD treatment did not significantly reduce volatile compound contents compared to single HHP or VFD. Gas chromatography–olfactometry showed that HHP–VFD raised the contents of floral-like volatile compounds (e.g., β-ionone) compared to the untreated sample. Sensory evaluation analysis confirmed that the overall liking was unchanged after the HHP–VFD treatment. The HHP–VFD combined treatment is effective in maintaining the flavor and extending shelf life, and is convenient for the portability and transportation of ready-to-drink juice.Keywords:high hydrostatic pressure;vacuum freeze drying;aroma compounds;blended juice;gas chromatography–olfactometry

Preparation of antifouling and highly hydrophobic cellulose nanofibers/alginate aerogels by bidirectional freeze-drying for water-oil separation in the ocean environment

Qiuyan Liu,Yuanquan Liu,Qian Feng,ChuChu Chen,Zhaoyang Xu

Oil spills frequently occur in the ocean, and adsorption is one of the effective ways to deal with oil spills. Compared with other adsorbent materials, biomass aerogel has superior selective adsorption capacity. CNF/SA aerogels with good mechanical properties (340 kPa at 90 % strain) and high adsorption capacity (88.91 g/g) were prepared by mixing cellulose nanofibers (CNF) with sodium alginate (SA) through bidirectional freeze-drying, ionic crosslinking, and surface modification to effectively solve the ocean oil spill problem. The bidirectional freeze-drying technology is a green and efficient technique for preparing layered microstructured composite aerogels. The prepared aerogels have a three-dimensional interpenetrating lamellar structure, low density (24.2 mg/cm 3 ), high porosity (97.85 %), and high hydrophobicity (WCA = 144.5°), can be calibrated and used repeatedly. It has potential applications in water-oil separation and can be used as an absorbent for effectively treating oil spills in the ocean environment.

Effect of Freeze-Drying and Spray-Drying on Emulsibility and Stability of Emulsions Stabilized by Covalent and Non-Covalent Whey Protein–Dextran Complexes

Zhen Li,Hongyu Cao,Yifei Wu,Hongbo Li,Guilian Sun,Kewen Li,Shuwen Zhang,Hongjuan Li,Jinghua Yu

This study focuses on the stability of whey protein isolate–dextran (WPI–D) complexes, exploring how their modification modes (covalent grafting/non-covalent mixing) and drying processes (spray-drying [SD]/freeze-drying [FD]) regulate structural properties and stability. Covalent WPI–D grafts (WPI-D-G) exhibit a higher degree of glycosylation, with significant fluorescence quenching and red shift. Fourier transform infrared (FTIR) spectral analysis reveals reduced absorbance of amide bands, collectively forming rigid cross-linked structures. Compared to non-covalent WPI–D mixtures (WPI–D-M), these structures exhibit superior emulsifying activity index (EAI), emulsion stability index (ESI), as well as stronger tolerance to environmental stresses (thermal stability: FD WPI–D-G (WPI–D-GF) maintain a particle size of 0.447 µm at 80°C, whereas SD WPI–D-G (WPI–D-GS) tend to aggregate; salt tolerance: stable at NaCl ≤ 20 mg/mL; pH stability: robust across pH 2–7). WPI–D-GF retain intact cross-linked structures, exhibiting enhanced emulsifying performance and colloidal stability (higher absolute zeta potential), whereas WPI–D-GS, despite forming smaller uniform spherical particles, undergo partial structural degradation. Regarding comparative stability under different conditions: WPI–D-GF outperforms WPI–D-GS in thermal stability, whereas covalent grafts from both drying methods demonstrate comparable salt and pH tolerance. These findings elucidate the structure–stability relationship of WPI–D complexes, thereby providing a theoretical foundation for regulating their stability through process optimization.

Development and Evaluation of a Novel Inhalable Liposomal Powder Co-Encapsulating ASSNAC and Pirfenidone via Spray Freeze-Drying for Targeted Pulmonary Fibrosis Therapy

Qinxiu Zhang,Shouwei Sun,Miaomiao Lu,Runxin Qin,Junxuan Ren,Lianjie Yao,Dianlong Jia,Jinjie Chang,Xiaohong Chu,Rui Wang,Fang Liu,Jun Li

Background:Pulmonary fibrosis (PF) is a progressive lung disease with limited therapies. Oral Pirfenidone (PFD), an approved anti-fibrotic, shows poor lung bioavailability and significant toxicity. S-Allylmercapto-N-acetylcysteine (ASSNAC) has been demonstrated to possess significant anti-inflammatory and antioxidant properties.Methods:In this study, dry powder inhaler formulations (DPIs) co-encapsulating ASSNAC and PFD in liposomes are reported. The formulation was prepared via spray freeze-drying (SFD) using L-leucine as both a cryoprotectant and a surface morphology modifier. The interfacial enrichment of L-leucine during atomization and freezing created a hydrophobic, corrugated surface that lowered particle surface energy, prevented liquid/solid bridge formation, and reduced hygroscopicity.Results:The resulting liposomal powders exhibited optimal aerosol performance: fine particle fraction (FPF) of 61.08% ± 2.45% and mass median aerodynamic diameter (MMAD) of 2.22 ± 0.11 µm. Cellular studies demonstrated that dual-loaded liposomes were efficiently taken up by Beas-2B and HFL-1 cells, with no cytotoxicity (cell viability > 90%) and negligible hemolysis. In the TGF-β1-induced in vitro fibrosis model, the combined treatment exerted prominent therapeutic effects. This regimen preserved normal epithelial morphology, accelerated wound repair, suppressed fibroblast invasiveness, and lowered the expression levels of Collagen I, Collagen III, and α-SMA. In bleomycin-induced pulmonary fibrosis rats, inhaled ASSNAC + PFD liposomal powder markedly relieved lung tissue injury and collagen accumulation. It restored redox balance and lowered pulmonary TGF-β1, hydroxyproline and collagen III levels. The formulation blocked TGF-β1 signaling and fibrotic gene expression.Conclusions:Pulmonary administration avoids oral pirfenidone-induced liver and stomach toxicity. Collectively, the ASSNAC + PFD co-encapsulated liposomal dry powder produced by SFD represents a safe and efficacious therapeutic strategy for PF.