Qingzi Nano

Foshan Lepton Precision Measurement And Control Technology Co.,Ltd（QINGZI NANO）is a national high-tech enterprise covering R & D, manufacturing, sales and technical services. And it’s a reputable manufacturer from China which specializes in electrospinning technology as well as biological 3D printing technology, electrospray printing and nanofibers materials. QINGZI NANO company's R&D team strength is very strong. At the same time, the company has established strategic cooperation with Berkley University, National University of Singapore, Xiamen University, Tsinghua University, Zhongshan University, South China University of Technology, Guangdong University of Technology and Jinan University. The company's products have been widely used in environmental protection, new energy, electronic information and biomedicine and other fields. Electrospinning products also received high-tech product certification. QINGZI NANO company has more than 80 patents, of which more than 50 patents for inventions, covering electrospinning technology, bio-3D printing technology and electrospray printing technology equipment and technology.

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Electrospinning series you want to know - L-polylactic acid (PLLA)

Catalog:

1. Properties of PLLA materials

2. Application of PLLA nanofibers in tissue engineering

3. Experimental parameters of electrospun PLLA

4. Common problems and solutions

1. Properties of PLLA materials

Since there is an asymmetric carbon atom in the lactic acid molecule, which has optical activity, polylactic acid can also be divided into dextral polylactic acid (PDLA), left-handed polylactic acid (PLLA), racemic polylactic acid (PDLLA), and non optical polylactic acid (Meso PLA). PLA is an important biodegradable polymer material, characterized by non-toxic, non irritating, biodegradable absorption, high strength, good plasticity, and easy processing and molding. The degradation cycle is 2~12 months.

Fig. 1 Enantiomeric form of lactic acid

2. Application of PLLA nanofibers in tissue engineering

PLLA is one of the first synthetic polymer materials recognized as suitable for tissue engineering due to its non-toxic, non irritating, biodegradable absorption and high strength. The nanofiber scaffold produced by the invention can be used for specific tissue engineering applications, including bone, cartilage, blood vessel and skin tissue regeneration.

Fig. 2 Application of PLLA stent in tissue engineering

(1) Bone tissue

In bone tissue engineering, electrospinning has been widely used to prepare nanofiber scaffolds, whose structure is close to the nano collagen fibers of bone. In actual preparation, electrospun PLLA scaffold will be prepared in combination with surface modification to guide cells to differentiate into bone lineage and achieve the best bone regeneration performance.

A research team successfully modified the surface of PLLA nanofibers prepared by electrospinning through the surface deposition of osteogenic ECM. These scaffolds were then used to detect the response of mouse bone marrow stromal cells after implantation of the scaffold. The results showed that compared with pure PLLA nanofibers, the mineral growth, ALP activity and cell morphology of the modified structure were in the best state.

(2) Cartilage tissue

Although PLLA nanofiber scaffolds have shown significant effects on cartilage repair, their fine fibers lead to limited bearing capacity.

PLLA nanofiber scaffold made by phase separation and pore forming agent leaching has been proved to be the optimal scheme for cartilage repair in vivo and in vitro. This is due to the high porosity and interoperability of these scaffolds, as well as their good degradability. In addition, the appropriate size of the scaffold hole also improves the functional characteristics of cartilage, thus providing some different solutions for the regeneration and repair of cartilage tissue.

(3) Vascular tissue

Recently, a research team has made multi-layer scaffolds for vascular tissue engineering: PCL, collagen and PLLA nanofibers are used to simulate the inner membrane, middle membrane and outer membrane respectively. These nanofibers were made into three-layer tubular scaffolds by continuous electrospinning, and cultured endothelial cells and smooth muscle cells for biological activity evaluation. The final evaluation experiment results showed that the collagen in the middle layer significantly improved the adhesion and proliferation of SMC, and the proliferation of endothelial cells increased significantly with culture, indicating the non cytotoxicity of the construct.

(4) Skin tissue

In dermal fibroblasts culture in vitro, the mixed scaffold induced higher cell seeding efficiency and improved fibroblast adhesion and proliferation compared with collagen sponge. On the other hand, in vivo wound healing evaluation showed that the composite scaffold healed faster and more effectively than the collagen scaffold. In most cases, PLLA, collagen and gelatin are often combined to produce nanofiber scaffolds, which show physical and biological characteristics matching with skin substitutes.

PLLA is also used to produce multilayer scaffolds that are very similar to natural skin structures. A research team has developed a new type of double-layer scaffold, which is composed of chitosan/PCL nanofiber pad on the surface and PLLA microporous disk on the bottom. In this work, keratinocytes and fibroblasts were cultured as epidermal equivalent and dermal equivalent respectively. The final results showed that the cell proliferation in the double-layer scaffold was higher than that in the single-layer CP nano pad and PLLA microdisk. In addition, the evaluation of genes and proteins showed that the wound healing was active, which again confirmed that the double-layer scaffold could provide a suitable microenvironment for stimulating skin regeneration.

Fig. 3 Small Aperture (125-250 μ m) In vitro cartilage differentiation of human bone marrow mesenchymal stem cells induced by β - lactamase scaffold Large specific aperture (425-600 μ m) The stents in our body better support cartilage formation.

Cited by: Capuana, E; Lopresti, F.;  Ceraulo, M.;  La Carrubba, V. Poly-l-Lactic Acid (PLLA)-Based Biomaterials for Regenerative Medicine: A Review on Processing and Applications.  Polymers 2022, 14, 1153.  https://doi.org/10.3390/polym14061153

3. Experimental parameters of electrospun PLLA

3.1 Experimental parameters for preparation of poly (L-lactide)/hydroxyapatite (PLLA/HA) nanocomposite scaffold

Material configuration: Dissolve 1g of PLLA (intrinsic viscosity 0.90-1.20dL/g) in 5mL of dichloromethane, and disperse 0.1g of nano HA powder (particle size<200nm) in the polymer solution under stirring, and transfer the obtained suspension to the medical syringe.

Electrospinning experiment parameters: positive voltage 15kV, liquid supply speed 1.5mL/h, needle 23G, spinning distance 15cm.

Reference: Rainer A, Spadaccio C, Sedati P, et al. Electrospun Hydroxapatite Functionalized PLLA Scaffold: Potential Applications in Sternal Bone Healing [J] Annals of Biomedical Engineering, 2011, 39(7):1882-1890.

3.2 Experimental parameters for preparation of PLLA/PCL oriented fiber scaffold

Material configuration: PLLA is dissolved in chloroform first, then in dimethylformamide (DMF) (4.25:0.75), while PCL is dissolved in chloroform/DMF (8:2). They were stirred for 3 hours, and then the polymer solution was loaded into the syringe by applying a positive voltage between the needle and the collector. The solution droplets leave the needle to form nanofibers and deposit at the same time. The percentage of PLLA/PCL is 47/53 wt%. The needle tip is placed 15 cm from the collector for PLLA and 20 cm for PCL, while rotating the disk at a linear rate set at 2800 rpm to collect parallel nanofibers.

Electrospinning test parameters: 5ml plastic syringe, 21 # needle, positive voltage (18 kV for PLLA, 24 kV for PCL)

Reference: Mashhadikhan M, Soleimani M, Parivar K, Yaghmaei P. ADSCs on PLLA/PCL Hybrid Nanoscaffold and Gelatin Modification: Cytocompatibility and Mechanical Properties Avicenna J Med Biotechnol.  2015 Jan-Mar; 7(1):32-8. PMID: 25926950;  PMCID: PMC4388888.

3.3 Experimental parameters for preparation of pure PLLA nanofibers

Material configuration: dissolve PLLA in hexafluoroisopropanol, with the mass fraction range of 8%~10%, 20G (1/2 inch, flat mouth) stainless steel needle, the needle is connected to the positive pole of high-voltage power supply, and the receiving roller is connected to the negative pole of high-voltage power supply

Electrospinning experiment parameters: the liquid supply speed is 0.5~3mL/h (depending on the electrospinning process), the roller speed is 300 rpm, the slide travel is 20cm, and the spinning voltage is positive 15kV and negative 5kV

4. Common problems and solutions

(1) The boiling point of the solvent is low, so it cannot be spun at high temperature to avoid the blockage of the needle tip due to the rapid evaporation of the solvent. 

(2) The solution shall be prepared by gradually adding particles or powders to prevent the dissolution rate from decreasing due to particle agglomeration and suspension.

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Electrospinning series you want to know - PVP (polyvinylpyrrolidone)

Catalogue

1. Electrospinning PVP (polyvinylpyrrolidone)

2. Development trend of PVP based biological scaffold

3. Research on the application of electrospun PVP in biomedical products

4. Experimental parameters of electrospun PVP

1. Electrospinning PVP (polyvinylpyrrolidone)

PVP (polyvinylpyrrolidone) provides hydrophilic and lipophilic chemical properties. As an excipient, it has been used in some conventional, controlled and new drug delivery systems. Because of its solubility and availability in various grades, it provides such functions as film forming, complexing, solubilization, adhesion, stability, suspension, thickening and other functions. It is also widely used in food, cosmetics, textiles, adhesives and other industries.

PVP has been found in a large number of biomedical applications. The unique properties of PVP are amphiphilic, hydrogen bond formation and complexation, solubility, and compatibility with other polymers and therapeutic agents. With the development of electrospinning, electro spray and 3D / 4D printing, PVP has been found to be an ideal material for preparing nanofibers. This paper focuses on the application of electrospun PVP in biomedical products.

2. Development trend of PVP based biological scaffold

The inertia, chemical stability, non-toxic or low toxicity, non irritation to biological system and biocompatibility of PVP make it one of the ideal materials for electrospun biological scaffolds. Natural polymers, such as chitosan, alginate, collagen and other natural materials, can more comfortably support cell proliferation and differentiation due to their inherent compatibility with ECM. In order to overcome the limitations of natural materials, PVP, as a polymer, plays a variety of functions as an additive, stabilizer, film-forming agent and adhesive in various medical fields of biomaterial applications. It can improve the mechanical strength of natural polymers. Moreover, PVP is a synthetic hydrophilic polymer, which attracts researchers due to its excellent biocompatibility, better processability, controllable degradability, and amphiphilic nature, and can produce scaffolds with required characteristics.

The biomedical applications of PVP nanofibers or nano scaffolds in different fields are listed below, such as tissue engineering, wound dressing, drug delivery, etc. These applications are developed by electrospinning, 3D printing and some other technologies. Some researchers have used PVP as a support material (porogen) to provide porous nanofibers with better performance.

Fig. 1 PVP based nanofiber manufacturing technology, application, drug delivery route and surface modification

3. Research on the application of electrospun PVP in biomedical products

3.1 Application of PVP as human implant

PVP nanofibers have potential applications in vascular implants, dental implants, organ implants, etc. A research team developed oriented PVP nanofibers through improved electrospinning technology, which includes conductive cylindrical electrodes with parallel plates. The improved technology can produce nanofibers with lower dispersion and better performance.

These neatly arranged nanofibers can imitate natural ECM to create an ideal environment for tissue regeneration, and can also find applications in sensors. PVP is used as a composite material together with other polymers such as chitosan and carboxymethyl cellulose (CMC), which can improve the performance of the entire manufacturing system. For example, the bioexcitation and biomineralization hydrogel scaffolds of pvp-cmc-caco3 have been developed, and the influence of the concentration of ionic solution used in the preparation has been studied. Researchers said that the hydrogel scaffold showed promising results in bone tissue regeneration.

Fig. 2 Different applications of PVP nano scaffolds prepared in combination with copolymers and inorganic substrates

3.2 Application of PVP in regenerative tissue engineering

Adopt poly ε- The biocompatibility of electrospun fiber scaffolds was studied with caprolactone (PCL) and polyvinylpyrrolidone (PVP) to develop different morphologies with conditioning properties. After the scaffold was formed, PVP was extracted to improve the surface porosity, which indicated that the performance was improved. These porous fiber scaffolds with hierarchical structure show good application prospects in the field of tissue engineering.

In the field of skin tissue and wound healing, a research team has developed different proportions of aloe PVP and aloe acetate PVP electrospun fibers, and studied their microstructure, mechanical properties, antibacterial, anti-virus, anti-inflammatory and wound healing properties. These studies indicate that the latter compound of aloe acetate PVP fiber may be a potential candidate for wound healing applications.

In addition, tissue engineering of heart and vascular tissue is becoming an interesting and inspiring field. In addition to PVP alone, composites with other polymers show promising results. As a part of composite materials, PVP adds its unique characteristics to hydrophobic composite polymers, making the scaffold system have better performance. Many studies have shown that PVP/PLLA blend yarn has improved performance compared with PLLA alone, and with the increase of PVP content in the composite, the cell distribution, cell growth and cell morphology are better. Therefore, the researchers claim that PLLA-PVP microfiber membrane may become a potential scaffold for vascular tissue engineering.

3.3 PVP as a matrix for delivery of therapeutic agents

For specific diseases, drug release, such as sudden release or sustained release or targeted release, is necessary according to the required level. With advanced technology and extensive research on polymers, scientists can develop drug delivery systems in the most appropriate way to meet individual needs. PVP is such a polymer, in which therapeutic agents can be delivered according to the required characteristics.

Electrospinning is used for the formation of PVP based nanofiber felt, including research nanofiber felt and hydroxypropyl- β- The complex of cyclodextrin and meloxicam is used for rapid dissolution and taste masking. A three-layer nanofiber mesh was prepared by continuous electrospinning with zein as the top layer and bottom layer, PVP in the middle. In order to obtain better mechanical strength and drug release function, PVP was mixed with graphene oxide.

In another study, PVP mixed graphene oxide and vancomycin hydrochloride were used as the core matrix, while PCL was used as the sheath polymer to prepare core-shell nanofibers by coaxial electrospinning. The system shows time programmed biphasic drug release. It was studied in vitro and in vivo. Rat bone marrow mesenchymal stem cell lines were used for in vitro studies and rats for in vivo studies. The survival time of cells was up to 72 hours.

4. PVP experimental parameters

4.1 Preparation of PVP/PCL core sheath fiber pad by coaxial electrospinning

Material configuration: Dissolve 1.92g PCL in 16mL DCM/DMF solvent mixture (3:1, v/v) to reach the polymer concentration of 0.12g/mL as the sheath spinning solution. The core spinning solution was prepared by adding 0.6 g of PVP powder to 6 mL of water/GO aqueous solution/DMF blend solution. The volume ratio of water, GO aqueous solution and DMF is 4:0:2, 2:2:2 and 0:4:2 to adjust the content of GO in the core composition. Connect the sheath spinning and water/GO aqueous solution/DMF blend solution to the customized spinneret (outer diameter 1.3 and inner diameter 0.3 mm, respectively).

Experimental parameters: The external and internal feeding rates are controlled by two injection pumps, running at 3.0 mL/h and 0.2 mL/h. The electrostatic power supply is provided by a high voltage power supply of 18.0 kV, and the fibers are collected on aluminum foil at a distance of 14 cm. The humidity of all electrospinning processes is 25 ± 3 ° C, and the relative humidity is 55 ± 4%. The prepared fiber pad was vacuum dried for 24 hours to remove residual solvent. The same procedure was used to manufacture pharmaceutical fiber pads, with the difference that VAN was dissolved in an aqueous solution for the core spinning solution.

References: Hui Yu, Peng Yang, Yongtang Jia, Yumei Zhang, Qiuying Ye, Simin Zeng, Regulation of biological drug release behavior by graphene oxide in polyvinyl pyridine/poly（ ε  caprolactone) core/sheath nanofiber mats, Colloids and Surfaces B: Biointerfaces, Volume 146, 2016, Pages 63-69, ISSN 0927-7765,  https://doi.org/10.1016/j.colsurfb.2016.05.052.

4.2 Customized PCL scaffold with PVP fiber and collagen/chitosan blend as skin substitute

Material configuration: chitosan (high molecular weight; degree of deacetylation=85%) and phosphate buffered saline, bovine collagen type I (AteloCollagen) and molecular weight 300 KDa, glacial acetic acid and 2-propanol (99.5%), PCL (Mn=80000), polyvinylpyrrolidone (PVP) (Mw=360000), glutaraldehyde (GA) 25% and 1,6-hexanediamine (HDA). Ethanol (99.8%). PCL at various concentrations of 15% was prepared by dissolving in glacial acetic acid to prepare 18% and 20% (w/v). Then the mixed solution was stirred gently with magnetic force at room temperature for 24 hours. Add the required deionized water and stir for 24 hours. Add 90% v/v acetic acid to each homogeneous solution, and then stir for an additional 30 minutes. In addition, 25% w/v PVP was dissolved in ethanol and gently stirred for 2 hours.

Experimental parameters: Electrospinning of PCL solution is carried out by changing the most effective parameters, including the distance (D) and voltage (V) from the nozzle to the collector. The collector speed is set to 800 rpm and is a constant experiment throughout the process. Electrospinning is carried out at room temperature with a relative humidity of about 20-25% and a 22G needle. Need to achieve the best results for bead free construction. It is used for simultaneously electrospinning PVP and PCL at different flow rates using two relative and independent spinnerets. Then the electrospun samples were immersed in water for different times to dissolve PVP fibers and the best results were selected for preparing the final samples.

References: Sadeghi avalshahr, A.R; Nokhasteh, S.;  Molavi, A.M.;  Mohammad-pour, N.;  Sadeghi, M. Tailored PCL Scaffolds as Skin Substitutes Using Sacrificial PVP Fibers and Collagen/Chitosan Blends.  Int. J. Mol. Sci.  2020, 21, 2311.  doi.org/10.3390/ijms21072311

This article is cited from: Malesh Kurakula, G.S.N. Koteswara Rao, Moving polyvinyl pyrrolidone electrospun nanofibers and bioprinted scaffolding toward multidisciplinary biomedical applications, European Polymer Journal, Volume 136, 2020, 109919, ISSN 0014-3057, doi.org/10.1016/j.eurpolymj.2020.109919.

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Application

The nanofiber membrane prepared by this technology has the advantages of small fiber diameter, large specific surface area, small pore diameter and high porosity. Because of such characteristics, electrospun nanofibers can simulate the extracellular mechanism and human tissue structure by improving the fibers. Different fiber structures or fibers with different pore diameters can provide different functions and carry different drugs.

It is widely used in tissue regeneration and repair, such as hernia repair, skin repair, dental model repair, myocardial repair, nerve repair, vascular repair, meningeal repair, etc.

Equipment introduction

Biomaterials 3D printer is a technology developed for tissue regeneration and repair, which is conducive to the proliferation and differentiation of cells and can quickly promote defective tissue repair and regeneration. The device can prepare scaffolds with a diameter of less than 1 micron, which is conducive to cell attachment and differentiation. And the equipment is equipped with 3 nozzles, which can switch multi-material, melt/solution and multi-process collaborative printing at any time.

Learn more: https://www.nanofiberlabs.com/

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Electrospinning machinee06 -nanofiberlabs

Electrospinning machine E06 is a laboratory scale machine with flexible design, modularization and integration of various functions. The machine allows the preparation of nanofiber materials using a single nozzle or multiple nozzles, and can exchange different modules for experiments. In order to better guarantee the electrospinning experiment, the machine also integrates an accurate temperature and humidity control system, and regularly records the experimental data. It also has a variety of collectors, such as roller collectors, plate collectors, tube collectors, and roll to roll collectors. Various nanofibers can be prepared, such as core-shell, hollow, oriented fibers and other nanofibers.

For more details, please click the link

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Electrospinning machine E04-nanofiberlabs

Electrospinning machine E04 is an integrated multi-functional machine that can simultaneously spin two formulations. The equipment has high spinning efficiency, more uniform coating of nanofiber film and large coating area. Equipped with positive and negative double high voltage power supply and counter spinning system, conjugate electrospinning can be realized and oriented fibers can be easily prepared. Modular design to realize multiple collector collection methods. The environmental control system is more comprehensive and can accurately control the environmental humidity and temperature. Suitable for experiments and small-scale mass production.

For more details, please click the link

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Electrospinning machine MF01-009 -nanofiberlabs

Electrospinning equipment (mf01-009) is a large-scale nanofiber electrospinning equipment developed for the field of biomedicine.Focus on solving the demand of R & D personnel in Colleges and universities and pharmaceutical enterprises for mass production and amplification of scientific research achievements,Realize the research and development of electrospun biomaterials from laboratory to industrial application,The equipment meets the requirements of high cleanliness, sterility and non-toxic material dissolution in the biological field,Nanofibers can be prepared in large scale, high yield and high uniformity.

For more details, please click the link

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Electrospinning machine M01-005 -nanofiberlabs

The biological 3D printer M01-005 integrates four functions of high-voltage electrospinning, near-field solution electrostatic direct writing, near-field melt electrostatic direct writing, and biological 3D printing. Users can purchase all functions at the same time, or flexibly configure some functions according to actual needs. Optional base version M01-001. The equipment integrates a variety of micro-nano processing technologies and can replace different nozzles and receiver modules. By using different spinning modules in combination, both conventional electrospinning and electrospray materials can be realized, and the preparation of multifunctional composite nanomaterials can be realized. Near-field direct writing technology can construct 2D or 3D micro-nanofibers, suitable for the design and manufacture of biological tissue engineering repair materials. Innovative support for a variety of software-assisted design of personalized patterns, custom pattern printing. A new generation of tools for the fabrication of 3D micro-nanofibrous materials.

For more details, please click the link

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Electrospinning machine E06 -nanofiberlabs

Electrospinning Machine E06 is a lab-scale machine with flexible design, modularization, and integration of various functions. The machine allows the preparation of nanofiber materials using a single nozzle or multiple nozzles, and different modules can be exchanged for experiments. To better guarantee the electrospinning experiment, the machine also integrates a precise temperature and humidity control system and records the experimental data regularly. A variety of nanofibers can be prepared, such as core-shell, hollow, oriented fibers, and other nanofibers.

For more details, please click the link

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Electrospinning machine E02 -nanofiberlabs

The Electrospinning Machine E02 provides a desktop experimental platform for creating uniform nanofiber membranes in the laboratory. For the research of materials science, technical textiles, and membranes, the device is small and compact, so it is suitable for placement on the laboratory bench and is easy to use. It is an economical and practical electrospinning machine.

For more details, please click the link

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Near field direct writing electrospinning machine M01-001 -nanofiberlabs

M01-001 is a desktop near-field direct writing electrospinning machine, which can solve the problem of insufficient laboratory space; The equipment is highly integrated and compact; it integrates a near-field solution direct writing module and a near-field melt direct writing module; Orderly arranged nanofibrous membranes, composite nanofibrous membranes, and 3D structured micro-nano bioscaffolds can be prepared by near-field direct writing technology; Support a variety of software-assisted designs of personalized patterns, and custom pattern printing.

For more details, please click the link

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Highlight of Important Academic Achievements of PLA (polylactic acid) in 2020

This paper introduces the PLA electrospinning related academic papers in 2020. These papers show that(PLA) is a synthetic, cytocompatible, and biodegradable biopolymer. PLA electrospinning technology is simple, and has gradually played an important role in biological medicine, medicine and other fields.

 1. Surface-porous and hollow poly(lactic acid) (SPH-PLA) and surface-porous and lotus-root-like PLA (SPL-PLA) nanofibres: preparation, quantitative analysis, and modelling

In this study, PLA nanofibres with unique microstructures were prepared by

coaxial electrospinning

. The cross-section of the prepared PLA nanofibres exhibited either a surface-porous hollow structure (SPH-PLA) or a surface-porous lotus-root-like structure (SPL-PLA). The morphology, hollow proportion, and porosity of the fibres under different electrospinning parameter conditions were analysed quantitatively; further, three-dimensional (3D) models of the PLA nanofibres were established under parameter conditions that provided the highest hollow proportion.

              Figure 1  3D models of (a) SPH-PLA and (b) SPL-PLA nanofibers

Link：https://sci-hub.st/10.1007/s11051-020-04965-w

2.In Vitro and In Vivo Comparison Study of Electrospun PLA and PLA/PVA/SA Fiber Membranes for Wound Healing

 In this study, PLA and PLA/PVA/SA nanofiber membranes were fabricated through electrospinning to produce a highly porous and large specific surface area that could promote wound healing. In vitro experiments showed that PLA and PLA/PVA/SA nanofiber membranes could all provide good support for the growth of rat fibroblasts (L929). Moreover, rat fibroblasts displayed slightly better adhesion and proliferation on PLA/PVA/SA than on the PLA fiber membranes. The in vivo potentiality of the PLA and PLA/PVA/SA fiber membranes was assessed in rat models of skin defects in which the PLA and PLA/PVA/SA fiber membranes significantly improved wound healing compared to commercially available gauzes. No significant differences in wound healing were observed between PLA and PLA/PVA/SA fiber membranes in our study.

Figure 2  Effects of PLA dressings on wound collagen deposition.

(A) Masson’s staining on day 16.

(B) Immunohistochemistry analysis of Collagen I (day 3) (a) control; (b) PLA group; (c) PLA/PVA/SA group.

(C) Western blot of Collagen I, (D) quantitative analysis of the Collagen I deposition.

Masson staining and PCR displayed the PLA fiber membrane promoted protein deposition compared to the PLA/PVA/SA fiber membrane. In addition, IHC suggested that PLA/PVA/SA dressing reduced the inflammatory response during early wound healing compared to the PLA fiber membrane. These findings highlight the utility of fiber membranes as novel wound-healing dressings.

Link：https://sci-hub.st/10.3390/polym12040839

3. Study on Reducing the Diameter of Polylactic Acid Fiber during Melt Electrospinning by Using Biobased Dyes as Conductive Additives

Electrospinning is widely used for the manufacture of fibers in the low-micrometer to nanometer range, allowing the fabrication of flexible materials with a high surface area.

 A distinction is made between solution and melt electrospinning. The former produces thinner fibers but requires hazardous solvents; whereas the latter is more environmentally sustainable because solvents are not required. However, the viscous melt requires high process temperatures and its low conductivity leads to thicker fibers.

Figure 3  Surface plots of fiber diameters in relation to the electrical resistance and viscosity of the melt. (a) PLA/alizarin compounds. 

(b) PLA/hematoxylin compounds. (c) PLA/quercetin compounds

Here, authors describe the first use of the biobased dyes alizarin; hematoxylin and quercetin as conductive additives to reduce the diameter of polylactic acid (PLA) fibers produced by melt electrospinning; combined with a biobased plasticizer to reduce the melt viscosity. The formation of a Taylor cone followed by continuous fiber deposition was observed for all PLA compounds; reducing the fiber diameter by up to 77% compared to pure PLA. The smallest average fiber diameter of 16.04 mu m was achieved by adding 2% (w/w) hematoxylin. Comparative analysis revealed that the melt-electrospun fibers had a low degree of crystallinity compared to drawn filament controls-resembling partially oriented filaments. The results form the basis of an economical and environmentally friendly process that could ultimately, provide an alternative to industrial solution electrospinning

Link：https://sci-hub.st/10.3390/ma13051055

4. Electrospinning-electrospraying of poly(acid lactic) solutions in binary chloroform/formic acid and chloroform/acetic acid mixtures

Poly(acid lactic) (PLA) is a synthetic, cytocompatible, and biodegradable biopolymer.

 It provides materials for drug delivery, food packing, and tissue engineering applications.

 Here, author provides the electrospinning of PLA (Mw = 26,000 Da) solutions (20–35% wt/vol) in binary chloroform/formic acid mixtures. The formic acid content between 20 and 40 vol% support smooth PLA fibers (average size between 231 and 637 nm).

Figure 4  SEM images of PLA materials obtained via electrospraying and

electrospinning of solutions in Chl at 10 (P10), 15 (P15), 20 (P20), 25 (P25), 30 (P30)and 35% wt/vol (P35).

The electrospraying of PLA solutions (10–25% wt/vol) in chloroform creates smooth microparticles (average size between 1.0 and 11.4 m). Contents of acetic acid higher than 10 vol% in binary chloroform/acetic acid mixtures prevent the formation of microparticles. Viscosity and conductivity measurements were carried out with the polymer solutions and the binary solvent mixtures, respectively. By modulating the polymer concentration and solvent system, we control the process, achieving electrospinning or electrospraying. Scanning electron microscopy and infrared spectroscopy characterized the PLA materials. This study reports accessible approaches to support micro- and nano-sized PLA materials.

Link:https://www.sciencedirect.com/science/article/abs/pii/S0167732220341726

5. Rapid visual alcohol dipstick based on transparent detection of hierarchical structured PLA/PVDF electrospun nanofibrous membrane

In recent years, the design of alcohol testing devise has received major attention from researchers considering the large number of traffic accidents caused by drunk driving. 

In this context, a simple electrospinning route has been presented to fabricate hierarchical structured PLA/PVDF nanofibrous membrane for achieving an enhanced transparent response to alcohol.

 The hierarchical structured PLA/PVDF membrane exhibits a synchronous combination of PVDF microspheres or nanofibers with dissolved PLA nanofibers.

Figure 5 (a) Digital photograph of the membrane. (b, c) UV–vis spectra of the membranes treated by alcohol. (d, e) UV–vis spectra of PLA/10%PVDF membrane. (f) The optical transmittance (at 550 nm) of the PLA/10%PVDF composite membrane

Thanks to the alcohol wettability, hierarchical structure, small refractive index (RI) discrepancy, and ultrathin nanofibers, the composite membrane exhibits superior transparency, exceeding 90%. Thus, this study offers a simple yet effective method to fabricate nanofibrous membranes and has a potential application as a dipstick for alcohol detection.

Link:https://www.sciencedirect.com/science/article/abs/pii/S2452213920302448

6. Gradient degradable nerve guidance conduit with multilayer structure prepared by electrospinning

Polymeric nerve guidance conduits (NGCs) with uniform tubular structure are widely used as scaffolds in nerve tissue engineering. However, massive collapse of NGCs has greatly impeded their further application.

Therefore, the gradient degradable nerve guidance conduit (GD-NGC) with multilayer structure is designed and fabricated via electrospinning technique.

The GD-NGC consists of five poly(lactic-co-glycolic acid) (PLGA) layers with different polylactic acid (PLA)/polyglycolic acid (PGA) ratios.

Figure 6  In vitro degradation of GD-NGCs. (a) The weight loss (%) and (b) pH variations of degradation medium in the process of GD-NGCs degradation. The morphologic changes of GD-NGCs after 4 weeks (c1-c3), 8 weeks (d1-d3) and 12 weeks (e1-e3). All experiments were performed in triplicates. The data are shown as means ± standard deviation (SD).

Compared to common NGCs, the novel GD-NGC degrades moderately and stepwise from inner to outer layers and also exhibits equivalent or better characteristics, such as porosity, water absorption capacity, mechanical property and biocompatibility. Collectively, GD-NGC has a promising potential for applications in nerve tissue engineering.

Link:https://www.sciencedirect.com/science/article/abs/pii/S0167577X20309435

7. Effect of ammonium polyphosphate and acrylic acid on NaCl treated electrospun PLA microfiber mat.

In this study, insulation material was developed using polylactic acid (PLA), which is one of the most widely-used biodegradable polymers.

The PLA was fabricated into a fiber mat shape using the electrospinning method, and NaCl salt was added to achieve thinner fiber diameter. This fiber-based mat showed lower thermal conductivity than PLA blocks but had poor tensile strength and heat stability.

To improve these mechanical and thermal properties, ammonium polyphosphate (APP) and acrylic acid (AA) were added; AA was used to better bond the APP with the polymer matrix.

The APP/AA mixed PLA fiber mat showed improved performance overall; with the addition of these materials, the thermal conductivity was about 35 mW/mK, which was slightly lower than before, the tensile stress improved about two times.

Figure 7  TGA result of fiber mat with slope of the each TGA graph: A, neat PLA/PLA + NaCl; B PLA + NaCl+APP; C, PLA + NaCl+AA; D, PLA + NaCl+AA+APP.AA, acrylic acid; APP, ammonium polyphosphate; PLA, polylactic acid; TGA, thermogravimetric analysis

Thermal stability was also augmented as the increase in the weight percentage of the sample residue after the thermogravimetric analysis indicated.

Link：https://sci-hub.st/10.1002/pen.25483

8. A biodegradable core-sheath nanofibrous 3D hierarchy prepared by emulsion electrospinning and its application in sustained drug release A sustained release system that composed of biodegradable core-sheath nanofibers in 3D hierarchy has been developed through electrospinning of water-in-oil precursor emulsion, in which theophylline dissolved in water was labeled as 'aqueous phase' and PLA solution was considered as 'organic phase'. SEM images revealed that the fibers crossed and overlapped with each other, forming a 3D network-like structure. TEM indicated that the drug was well incorporated into PLA nanofibers, forming a core-sheath structure, which represented a reservoir-type delivery system. The fiber scaffolds were further characterized by FTIR, XRD, TGA, and DSC, which proved theophylline was successfully loaded into the fibers in an amorphous form. The release of drug consisted of three sequential stages, in which the release rate decreased successively. The changes on release rate were proved to be related to the drug diffusion and polymer degradation. 

Figure 9 Possible mechanism of drug release from the composite fiber

At nearly 30 days, the drug still released continuously. This was accomplished by the gradually swelling and degradation of PLA. The successful preparation of the 3D core-sheath nanofibers can incorporate a water-soluble drug in a biodegradable polymer, which effectively protected the activity of the drug, inhibited a sudden release and accomplished sustained release. 

Link：https://sci-hub.st/10.1007/s10853-020-05205-1

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More information please feel free to contact us

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What Are The Applications of Nanofiber Instant Oral Collapse Tablets?

 #nanofiber #instant #oral #collapse #tablets #mouth #nanometer #form

 ◆ A large number of pharmaceutical ingredients can be added into the solvent as raw materials for nanofiber mouth collapse tablets. ◆ The nanometer form of the active components with the fiber dissolution deep release.

 Oral collapse tablet is a new kind of medicine preparation that can be automatically disintegrated into numerous particles and taste sweet within 30 seconds after being placed on the tongue. Because it disintegrates fast, absorbs quickly, and does not need to drink water after taking the medicine, it is very suitable for some special patients (mental illness, Alzheimer's disease, epilepsy, etc.) and the elderly, children to take.

 Application Scenario of Nanofiber Instant Oral Collapse Tablets

◆ Emergency drugs that can be absorbed by oral mucosa or drugs that need to take effect quickly. ◆ Medication for patients with dysphagia (such as patients with esophageal cancer). ◆ If the patient does not take the initiative or cooperate with the medicine. ◆ Drugs to increase the contact area or reduce gastrointestinal irritation. ◆ Medication for children, old people, patients with difficulty in changing their body position in bed, and patients with water shortage.

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How To Electrospin Electrospun Casein Nanofibers Mats?

 #electrospin #electrospun #casein #nanofibers #mats

 Casein is the major precipitated protein of milk at the temperature of 20℃ and a pH value of 4.6. Casein is a phosphorus-containing protein, which has a high content and nutrient value. Bovine casein is made up of as1-, as2-, k-, and b-casein. These four monomers constitute the spatial structure of casein via a-helix, b-sheet, and b-turn. b-Casein from bovine can be used as a superior emulsifier and colloid stabilizer. The pH value is 4.8, which is the isoelectric point of casein. Casein has excellent steric stability to dispersed oil/fat droplets under neutral pH.

 A solution containing only casein could not be electrospun due to its strong intermolecular force and 3D structure. However composite dispersions blending PEO or PVA with casein could be electrospun successfully as indicated in Figure. The 10% (w/w) casein solutions containing 80% PEO or 50% PVA are used to electrospin with average fiber diameters ranging from 100 to 500 nm.

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How To Produce Electrospun Gelatin Nanofibers?

 #electrospun #gelatin #nanofibers #nanoscale #nanofiber #electrospinning

 Gelatin is the homologous protein of collagen and partially hydrolyzed by it. The amino acid composition of gelatin is close to that of collagen. Gelatin molecules can form positive ions, anions, or zwitterions in solutions with different pH values. Collagen has a rod-shaped triple-helix structure, which is partially separated and broken when it is hydrolyzed. According to the different preparation methods, gelatin can be divided into two types. Type A, derived from hog skin and hydrolyzed by acid, has good plasticity and elasticity. Type B is mainly hydrolyzed by alkali from bones and animal skins and has a good hardness performance. The intensive use of gelatin in food is in gel desserts because of the unique feature of “melting at mouth temperature.” It has also been used in photographic emulsions to protect colloid (Figure).

 Thickening and stabilizing are the main applications in the food of gelatin as well as electrospun gelatin nanofibers, of which the amounts are smaller and the effects are stronger. The concentration of type B gelatin powder from bovine skin and the applied voltage have been investigated in research by Okutan et al. It is demonstrated that electrospun gelatin nanofibers are nanoscale only at the concentration of 20% (w/v) gelatin. Furthermore, the lower the applied voltage is, the higher the z potential and diffusion coefficient values for electrospun gelatin nanofiber dispersions are. According to a study, gelatin from cold-water fish skin is electrospun and then crosslinked. Water or concentrated acetic acid served as electrospinning solvents and both of them are electrospun successfully. There are three different techniques, namely GTA vapor, genipin, and dehydrothermal treatment, applied in the crosslinking process. The results of three studies show that fish gelatin modified with GTA is the most suitable substrate.

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How To Make Silk Electrospinning Nanofibers?

 #silk #electrospinning #nanofibers #nanospheres #nanofilaments #nanostructure

 Silks are divided into mulberry silks and non mulberry silks. Silkworm silk, an established fiber, is widely used in the textile industry. Silk fibroin (SF) is extracted from Bombyx mori silk, which is known as mulberry silk, and consists of two chains, a heavy chain and a light one, on which is a glycoprotein, called P25. The proportions of the heavy chain: light chain: P25 are 6:6:1. However, there is a lack of the light chain and P25 in non mulberry silks. Great differences are found between the two kinds of silk in bioactivity, mechanical properties, and degradation behavior due to the diversity of their structures.

 The characteristics of silk are biocompatibility, extensibility, biodegradability, high strength, and minimal production of inflammatory reactions. SF is extracted from B. mori cocoons. A 4% (w/w) solution is cast on polystyrene petri dishes and dried for 12 h and 4 days respectively to obtain silk films mainly containing nanospheres or nanofilaments. Afterward, they are dissolved in 98% formic acid and still remain stable. It has been proved that SF nanofilaments have better spinnability than SF nanospheres due to the lower viscosity. Apart from this, the average diameter of the fibers increases with increasing concentration of SF nanofilaments (Fig. 1), which implies that controlling the size of fibers could be easily achieved by changing the SF nanostructure and concentration. It has been reported that b-sheet content and fiber hydration have effects on the mechanical properties of an engineered protein named eADF4(C16), which is a spider silk mimic. It has been demonstrated that the aligned fibers fabricated with single proteins have good extensibility and toughness through adequate hydration (Fig. 2)

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Nanofiber Facial Mask Using Guide

Our company's new nanofiber facial mask production line, together with the spinning raw materials to help you easily develop and produce a new type of functional nanofiber facial mask.

 Benefits of nanofiber facial mask:

Electrospinning nanofibers have the advantages of diversity, high specific surface area, high porosity, and good air permeability, which can absorb and release essence more effectively and fit the skin better. The mask base material also may according to the need to add the effective component to carry on the electrospinning, enhances the masking effect.

1. Good sense of application

Good characteristics of percutaneous release/cosmetic active ingredients. Within a certain period of time, the drug/cosmetic active ingredient is completely released at a certain rate to achieve the desired cosmetic efficacy.

2. Fast absorption

As a drug delivery carrier, nanofiber has a great specific surface area and porous structure, strong mutual penetration with other substances, which is very conducive to the diffusion and dissolution of drugs, so as to overcome the cuticle on the skin molecule penetration resistance, improve the number of cosmetic ingredients through the skin, improve the percutaneous absorption of drugs.

3. Final product form: facial mask, forehead patch, eye patch, acne patch

https://www.qingzitech.net/nanofiber-facial-mask-production-line