目的 合成可生物降解的基因载体，并分析其生物毒性及转染率。 方法 低分子量聚乙烯亚胺（PEI）通过双硫键交联合成可降解的高分子量PEI衍生物（SS-PEI），通过红外光谱和核磁波谱分析技术分析其化学结构，采用细胞活力实验和检测大鼠肝肾功能指标分析其细胞和体内毒性，并转染羟基荧光素修饰的siRNA（FAM-siRNA）分析细胞转染率。 结果 红外波谱和核磁波谱分析可见酰胺键的特征波谱，噻唑蓝法和肝肾功能指标显示SS-PEI不同剂量组与对照组的差异均无统计学意义（P＞0.05），SS-PEI/FAM-siRNA转染率为（76.0 ± 2.8）%。 结论 SS-PEI的合成可明显提高装载siRNA的效率，具有安全、高效等特点。
Hydrogel is a creative polymeric biomaterial which can resemble extracellular matrix (ECM) in vitro. Hydrogel is also a material with intrinsic bioinert, but it can offer mechanical support and developmental guide for cell growth and new tissue organization by designing physicochemical and biological properties of hydrogels precisely. This review mainly introduces design of hydrogels, properties and applications in tissue engineering and regenerative medicine, drug delivery, stem cell culture and cell therapy.
ObjectiveTo summarize the research progress of tissue engineering technology to promote bone tissue revascularization in osteonecrosis of the femoral head (ONFH).MethodsThe relevant domestic and foreign literature in recent years was extensively reviewed. The mechanism of femoral head vascularization and the application progress of tissue engineering technology in the promotion of ONFH bone tissue revascularization were summarized.ResultsRebuilding or improving the blood supply of the femoral head is the key to the treatment of ONFH. Tissue engineering is a hot spot in current research. It mainly focuses on the three elements of seed cells, scaffold materials, and angiogenic growth factors, combined with three-dimensional printing technology and drug delivery systems to promote the revascularization of the femoral bone tissue.ConclusionThe strategy of revascularization of the femoral head can improve the local blood supply and delay or even reverse the progression of ONFH disease.
In existing vascular interventional surgical robots, it is difficult to accurately detect the delivery force of the catheter/guidewire at the slave side. Aiming to solve this problem, a real-time force detection system was designed for vascular interventional surgical (VIS) robots based on catheter push force. Firstly, the transfer process of catheter operating forces in the slave end of the interventional robot was analyzed and modeled, and the design principle of the catheter operating force detection system was obtained. Secondly, based on the principle of stress and strain, a torque sensor was designed and integrated into the internal transmission shaft of the slave end of the interventional robot, and a data acquisition and processing system was established. Thirdly, an ATI high-precision torque sensor was used to build the experimental platform, and the designed sensor was tested and calibrated. Finally, sensor test experiments under ideal static/dynamic conditions and simulated catheter delivery tests based on actual human computed tomography (CT) data and vascular model were carried out. The results showed that the average relative detection error of the designed sensor system was 1.26% under ideal static conditions and 1.38% under ideal dynamic stability conditions. The system can detect on-line catheter operation force at high precision, which is of great significance towards improving patient safety in interventional robotic surgery.
ObjectiveTo review the research progress of intra-articular targeted delivery of nanomaterials in the treatment of osteoarthritis (OA). MethodsThe domestic and foreign related literature on intra-articular targeted delivery of nanomaterials for the treatment of OA was extensively reviewed, and their targeting strategies were discussed and summarized. Results Rapid drug clearance from the joint remains a critical limitation in drug efficacy. Nanocarriers can not only significantly improve the residence profiles of drugs in the joint, but also achieve targeted delivery of drugs to specific joint tissues through active or passive targeting strategies. Conclusion With the continuous development of various emerging tissue- or cell-specific drugs, the targeted delivery of drugs with nanomaterials promise to realize the clinical translation of these drugs in the treatment of OA.
Sodium alginate (SA) is a kind of natural polymer material extracted from kelp, which has excellent biocompatibility, non-toxicity, biodegradability and abundant storage capacity. The formation condition of sodium alginate gel is mild, effectively avoiding the inactivation of active substances. After a variety of preparation methods, sodium alginate microspheres are widely used in the fields of biomaterials and tissue engineering. This paper reviewed the common methods of preparing alginate microspheres, including extrusion, emulsification, electrostatic spraying, spray drying and coaxial airflow, and discussed their applications in biomedical fields such as bone repair, hemostasis and drug delivery.
Gene therapy is designed to introduce genetic material into the cells of a patient via virus to enhance, inhibit, edit or add a genetic sequence, results in a therapeutic or prophylactic effect. Gene therapy has brought positive influence and great potential for the treatment of retinal diseases including genetic retinal diseases and acquired retinal diseases. In addition to the constant optimization of gene vectors, the exploration of different drug delivery techniques has brought different therapeutic effects for gene therapy of retinal diseases. The main delivery methods include subretinal injection, intravitreal injection, suprachoroidal injection. Considering the transfection efficiency and safety of delivery methods, emerging sub-inner limiting membrane injection and noninvasive gene delivery are under investigation. The selection of gene delivery method is very important for the safety and effectiveness of gene therapy for retinal diseases. It is not only related to the development of equipment and technology, but also related to the modification of adeno-associated virus, the selection of promoter and the specific retinal cells that the target gene wants to be transfected. Therefore, the most appropriate method of gene delivery should be selected according to the final gene therapy agent and the specific transfected cells after taking all these factors into consideration.
Methylcellulose is a semi-flexible cellulose ether derivative, whose hydrogels are thermosensitive and reversible, with good biocompatibility and adjustable function, and its application has attracted much attention in the biomedical field. In this paper, the application of methylcellulose-based thermo-sensitive hydrogels in biomedical field was reviewed. Based on the mechanism of gelation and influencing factors of methylcellulose, this paper focused on the recent advances in biomedical applications of methylcellulose-based hydrogels, including drug delivery, regenerative medicine, and other related fields. The current achievements in these fields were summarized in the form of lists in this paper to provide ideas and tendencies for future research. Finally, the future development of multifunctional methylcellulose-based hydrogel materials with improved performance was also discussed.
Microneedles have emerged as the new class of local drug delivery system that has broad potential for development. Considering that the microneedles can penetrate tissue barriers quickly, and provide localized and targeted drug delivery, their applications have gradually expanded to non-transdermal drug delivery recently, which are capable of providing rapid and effective treatment for injuries and diseases of organs or tissues. However, a literature search revealed that there is a lack of summaries of the latest developments in non-transdermal drug delivery research by using biomedical polymeric microneedles. The review first described the materials and fabrication methods for the polymeric microneedles, and then reviewed a representative application of microneedles for non-transdermal drug delivery, with the primary focus being on treating and repairing the tissues or organs such as oral cavity, ocular tissues, blood vessels and heart. At the end of the article, the opportunities and challenges associated with microneedles for non-transdermal drug delivery were discussed, along with its future development, in order to provide reference for researchers in the relevant field.
The treatment of hereditary retinopathy depends on gene replacement or editing therapy, and adeno-associated virus (AAV) vector is one of the most widely used gene transfer vectors. The delivery methods of AAV vector-mediated target genes to the retina inlucde intravitreal injection, subretinal injection, and suprachorioidal injection. Intravitreal injection of AAV vector is currently the most commonly used delivery route, which can effectively improve the functions of retina disorders such as blinding retinal dystrophy in mice. Subretinal injection of AAV vector can deliver the target gene to the local retina, resulting in stronger efficiency of transfection and gene expressio, however, the high technical operations are required. In recent years, as a new high-profile delivery route suprachorioidal injection of AAV vector can achieve more extensive transfection of target genes in the retina of rabbits and rats. At present, the efficiency of AAV vector transduction in the retina is affected by the delivery mode. In the future, it is necessary to further explore the effect of AAV vector delivery mode on the transduction efficiency in order to find an important delivery route for mediating gene therapy for retinal diseases.