壳聚糖基可注射型温度敏感性水凝胶

壳聚糖基可注射型温度敏感性水凝胶是一种pH值中性的,在室温或低于室温时可保持液态,温度达到体温时可凝胶化的材料,有望被广泛应用于药物释放和组织工程领域,作为多肽和蛋白质等生物活性药物的可注射型释放载体或组织修复材料.本文介绍了壳聚糖基可注射型温敏性水凝胶的种类、特性、机制和应用等方面的研究进展.     

壳聚糖基载药纳米微粒制备研究进展

有关可生物降解多糖类纳米微粒用作给药载体的研究，近年颇受重视。简要评述了壳聚糖基载药纳米微粒的制备方法，包括共价交联、离子诱导、沉淀析出、大分子复合和自组装方法及其研究进展。     

壳聚糖基抗菌材料的制备研究新进展

壳聚糖及其衍生物的抗菌活性和优良加工性能,使其成为巨大潜力的抗菌材料,可用于食品保鲜、伤口敷料、纺织品功能化和组织工程等方面。本文综述了近年来壳聚糖基抗菌材料的制备研究新进展,并讨论了壳聚糖基材料的抗菌模型及影响抗菌活性的因素,希望对壳聚糖基抗菌材料的制备及抗菌活性的优化提供指导。     

磁应答型药物递送载体的设计与构建

复合磁性生物材料的发展和应用已引起生物医学领域的极大关注。磁性纳米粒子因其易功能化而具有靶向药物传递、可控药物释放及磁成像特性逐渐成为药物传递和新型诊疗领域最有前途的材料之一。基于磁性纳米粒子或掺杂的铁氧化物构建的远程触发磁性载药递送系统,有望实现在运输过程中携载药物不泄露的情况下,提高药物递送效率且对病灶周围的健康细胞无毒或低毒性。为构建理想的可控靶向磁性药物递送系统,多种材料或配体可以与磁性纳米粒子复合来构建更安全有效的磁性药物递送系统。一些生物分子、聚合物及天然产物等通过与磁性纳米粒子相结合,构建出可用于药物传递且具有独特性质的磁性复合新材料。迄今为止,具有磁场应答能力的磁性药物递送载体已经在远程控制药物释放领域得到了长足发展。本文总结了近年来磁性药物递送载体作为远程控制治疗体系在设计与构建上的研究进展。重点关注了磷脂分子、聚合物、多孔微纳米材料以及天然产物等与其构建的复合材料,并对当前磁性复合特定给药载体的优点、局限及发展前景等做了简要阐述。     

同轴静电纺丝技术制备药物缓释载体的研究进展

由于纳米纤维在组织工程支架材料,药物传递载体等方面的潜在应用,使得具有高比表面积的静电纺丝纳米纤维得到了很大的关注。静电纺丝技术是一种简单、有效的微／纳米技术,而同轴静电纺丝则是在传统静电纺丝技术上发展起来的新方法,单步即可制备连续的壳一芯结构纳米纤维或中空纳米纤维。这也使得静电纺丝纳米纤维在组织工程和药物缓释等领域有...     

壳聚糖基智能凝胶材料及其应用

壳聚糖是一种通过超分子作用形成凝胶的氨基多糖,可形成配合物,如聚电解质配合物,共价配合物和自组装配合物等。壳聚糖基智能凝胶在控制释放载体、分离膜、固定化基质、人工细胞外基质和场响应材料等方面应用前景广阔。     

壳聚糖基抗菌水凝胶的应用及研究进展

抗菌生物材料因其能够有效抑制细菌感染而被公认为是重要的抗生素替代品。其中抗菌水凝胶因制备工艺简单,结构多样,具有易负载和可控药物释放性、良好的生物相容性和抗菌性等多种特殊功能而受到越来越多的关注。壳聚糖及其衍生物具有高抗菌性、低毒性、生物相容性和降解性等优点被广泛用作抗菌水凝胶材料。本文根据壳聚糖基抗菌水凝胶的性能和抗菌机理,综述了近年来在固有抗菌水凝胶、光响应性抗菌水凝胶、荧光抗菌水凝胶、负载抗菌药物水凝胶和协同抗菌水凝胶等方面的研究进展,探讨了壳聚糖基抗菌水凝胶目前所面临的挑战,并对其未来发展作了展望。     

壳聚糖基智能水凝胶的研究进展

壳聚糖是一种天然高分子,含有氨基和羟基等特征基团;水凝胶是一种高分子交联网络体系,具有亲水性,在水中能够溶胀并保持大量水分而不溶解;“智能化”是自发地对外界环境刺激产生响应的一种特性.壳聚糖基智能水凝胶具有良好的生物相容性和可降解性,正倍受广大研究学者的关注.文章综述了近年来关于pH敏感型、温度敏感型以及pH/温度双重敏感型壳聚糖基智能水凝胶的研究概况,介绍了壳聚糖基水凝胶在医学领域如组织工程、药物释放方面的应用并对其未来的发展方向进行了探讨.     

DNA纳米结构在药物转运载体和智能载药中的应用进展

纳米材料具有荷载效率高、靶向性能好、半衰期较长等优点, 非常适于作为药物转运载体, 可有效提高药物的水溶性、稳定性和疾病治疗效果.目前, 开发具有良好生物相容性、可控靶向释放能力和精确载药位点的理想药物转运载体, 仍是该领域存在的挑战性问题和当前研究的重点.自组装DNA纳米结构是一类具有精确结构、功能多样的纳米生物材料, 具有良好的生物相容性和稳定性、较高的膜渗透性和可控靶向释放能力等优点, 是理想的药物转运载体和智能载药材料.本文总结了DNA纳米结构的发展历程、DNA纳米结构作为药物转运载体的研究现状、动态DNA纳米结构在智能载药中的应用进展, 并对其发展前景进行了展望.     

聚合物纳米体系在药物和基因载体中的应用

聚合物纳米体系在药物传递和基因载体方面具有重要的科研价值和广阔的应用前景,这方面的研究已成为当今生物医学材料界最活跃的领域之一。本文对聚合物纳米体系在药物传递和基因载体方面的应用做了简单的概括,介绍了其中具有代表性的几种应用体系,如聚合物药物、聚合物-药物偶联体、聚合物-蛋白质偶联体、连接药物的聚合物胶束以及聚合物-基因复合物等,对当前研究的热点以及研究中存在的问题和不足进行了评述。     

Calcium Phosphate Nanocarriers Dual‐Loaded with Bovine Serum Albumin and Ibuprofen: Facile Synthesis,Sequential Drug Loading and Sustained Drug Release

A simple and green strategy is reported for the preparation, drug loading, and release properties of a drug delivery system consisting of calcium phosphate (CP) nanocarriers dual‐loaded with bovine serum albumin (BSA) and hydrophobic drug ibuprofen (IBU). The sequential loading of BSA and IBU in calcium phosphate nanocarriers and in vitro simultaneous release of BSA and IBU are realized and investigated. In this method, BSA, which is used as a model protein drug, is encapsulated in situ in calcium phosphate nanocarriers. Subsequently, the typical hydrophobic drug IBU is loaded in the BSA/CP drug delivery system, forming the IBU/BSA/CP dual drug delivery system. The experiments reveal that the preloaded BSA not only reduces the cytotoxicity of calcium phosphate nanocarriers but also significantly improves the IBU drug loading capacity in calcium phosphate nanocarriers and greatly extends the duration of drug release. Thus, the as‐prepared IBU/BSA/CP dual drug delivery system is promising for drug delivery applications.     

Recent Progress in Transdermal Nanocarriers and Their Surface Modifications

Transdermal drug delivery system (TDDS) is an attractive method for drug delivery with convenient application, less first-pass effect, and fewer systemic side effects. Among all generations of TDDS, transdermal nanocarriers show the greatest clinical potential because of their non-invasive properties and high drug delivery efficiency. However, it is still difficult to design optimal transdermal nanocarriers to overcome the skin barrier, control drug release, and achieve targeting. Hence, surface modification becomes a promising strategy to optimize and functionalize the transdermal nanocarriers with enhanced penetration efficiency, controlled drug release profile, and targeting drug delivery. Therefore, this review summarizes the developed transdermal nanocarriers with their transdermal mechanism, and focuses on the surface modification strategies via their different functions.     

Effects of the Molecular Weight of PLGA on Degradation and Drug Release In vitro from an mPEG-PLGA Nanocarrier

We successfully synthesized four kinds of copolymers with varying molecular weights of poly(lactide-co-glycolide)(PLGA) to yield methoxy-poly(ethylene glycol)-block-poly(lactide-co-glycolide)(mPEG-PLGA) nanocarriers:mPEG-PLGA(3k), mPEG-PLGA(9k), mPEG-PLGA(11k) and mPEG-PLGA(16k). An antitumor drug, 10-hydroxycamptothecin(HCPT), was encapsulated into the mPEG-PLGA nanocarrier cores by self-assembly in dialysis. The lower molecular weight nanocarriers degraded more quickly, resulting in mass loss, pH decline, and a rapid HCPT release rate in vitro. The degradation and drug release of the nanocarriers were dependent on the PLGA molecular weight. However, the larger molecular weight nanocarriers could not increase the loading content and encapsulation efficiency. Considering the antitumor effect of these nanocarriers, the mPEG-PLGA(9k) nanocarrier, which had the highest drug loading content[(7.72±0.57)%] and a relatively high encapsulation efficiency[(22.71±5.53)%], is an optimum agent for drug delivery.     

Uniform chitosan microspheres for potential application to colon-specific drug delivery

Uniform chitosan microspheres have been fabricated and weakly crosslinked for potential applications in colon-specific drug delivery. The effects of microsphere size, crosslinking density and electrostatic interactions between the drug and chitosan on drug release were studied, employing model drugs of different acidities. When the drug was basic, all chitosan spheres exhibited 100% release within 30 min. As the acidity of the drug increased, the release slowed down and depended on the crosslinking density and microsphere size. The release of weakly acidic drug was most suppressed for large spheres (35-38 microm), while the small spheres (23-25 microm) with higher crosslinking exhibited the most retention of highly acidic drug, indicating that they are a promising candidate for colon-specific delivery.     

Encapsulation of cyclodextrin complexed simvastatin in chitosan nanocarriers: A novel technique for oral delivery

The purpose of the present work was to design and investigate the potential of novel hydroxylpropyl-beta-cyclodextrin (HP-β-CD) and chitosan nanocarriers (NCs) for effective delivery of model, poorly water soluble drug simvastatin. The prepared system was characterized for particle size, particle size distribution (PDI), zeta potential, differential scanning calorimetery, x-ray diffraction, encapsulation efficiency and drug release studies. The results revealed that among the selected ratios of tripolyphosphate/chitosan, ratio 1:4 and 1:5 proved to be optimum in terms of particle size, particle distribution and drug release profile. The average size of nanoparticles increased from 516 to 617 and 464 to 562 nm for ratio 1:4 and 1:5 with increase in drug/HP-β-CD amount. To assess interactions and whether the simvastatin was incorporated in the NCs in its crystalline or amorphous form DSC and XRD were performed. These results suggest that the encapsulation process produces a marked decrease in crystallinity of simvastatin and/or confers to a nearly amorphous state of drug in NCs. Results reveled that with increase in the amount of HP-β-CD/drug the final loading of the NCs increased due to increased solubilization of simvastatin in the presence of HP-β-CD. The in vitro release profile of prepared NCs showed initial fast release (burst effect) followed by a delayed release pattern. In conclusion, these nanocarriers constitute a novel and efficient system for encapsulation and oral delivery of poorly soluble drugs.     

Dendrimers and miktoarm polymers based multivalent nanocarriers for efficient and targeted drug delivery

The delivery of biologically active agents to the desired site in the body and intracellular organelles is still a big challenge despite efforts made for more than five decades. With the elaboration of synthetic methodologies to branched and hyperbranched macromolecules such as miktoarm stars and dendrimers, the focus has shifted to nanocarriers able to release and direct drug molecules to a desired location in a controlled manner. We present here recent developments in the field of targeted drug delivery with a focus on two specific macromolecular nanocarriers, dendrimers and miktoarm stars, and provide examples of these nanocarriers tested in different biological systems. A particular attraction of miktoarm stars is their versatility in achieving superior drug loading within their self-assembled structures. Advantages of dendrimers over linear polymers are that the former provide a platform for development of multivalent and multifunctional nanoconjugates, in addition to their ability to accommodate a large number of molecules inside, or at their surfaces.     

Ciprofloxacin Loaded Alginate/Chitosan and Solid Lipid Nanoparticles,Preparation, and Characterization

The aim of the present study was to develop controlled drug delivery systems based on nanotechnology. Two different nanocarriers were selected, chitosan-alginate nanoparticles as hydrophilic and solid lipid nanoparticles as lipophilic carriers. Nanoparticles were prepared and characterized by evaluating particle size, zeta potential, SEM pictures, DSC thermograms, percentage of drug loading efficiency, and drug release profile. The particle size of SLNs and Chi/Alg nanoparticles was 291 ± 5 and 520 ± 16. Drug loading efficiency of Chi/Alg and SLN particles were 68.98 ± 5.5% and 88 ± 4.5%. The drug release was sustained with chitosan-alginate system for about 45 hours whereas for SLNs >98% of the drug was released in 2 hours. Release profile did not change significantly after freeze drying of particles using cryoprotector. Results suggest that under in vitro condition chitosan/alginate systems can act as promising carriers for ciprofloxacin and may be used as an alternative system in sustained delivery of ciprofloxacin.     

Recent development in near infrared light-responsive polymeric materials for smart drug-delivery systems

Stimuli-responsive drug delivery systems (DDS) may overcome the drawbacks of conventional chemotherapy for cancer treatment. In particular, light-responsive polymer-based DDS may ensure spatio and temporal control in drug delivery. In this regard, near infrared (NIR) light triggered drug nanocarriers present several advantages when compared to UV–visible light triggered nanocarriers. This review surveys the recent development on the design, synthesis, functions, and applications of NIR photo-sensitive compounds in the development of long-wavelength light-responsive nanocarriers. Diverse NIR light responsive groups such as coumarin (CM), ortho-nitrobenzyl (ONB), 2-diazo-1,2-naphthoquinone (DNQ) and spiropyran (SP) derivatives and their photo-cleavage reaction mechanisms are discussed, as well as the use of indocyanine green (ICG) and its photo-thermal application. The loading into polymeric nanocarriers of up converting nanoparticles (UCNPs) which can convert NIR light into UV or visible light is also discussed. The described DDS are classified on the basis on the photo responsive groups. In details, the behavior of different polymeric materials such as micelles, hydrogels bearing photo responsive groups linked to bioactive molecules which are released under NIR light irradiation is reviewed and discussed. A section relative to commonly used instrument setup for drug release studies by NIR light irradiation is also presented for better understanding how the light has been used to irradiate in various experimental situations.     

pH and ionic sensitive chitosan/carboxymethyl chitosan IPN complex films for the controlled release of coenzyme A

pH and ionic sensitive interpenetrating polymer network (IPN) complex films based on chitosan (CS) and carboxymethyl chitosan (CM-CS) were prepared by using glutaraldehyde as crosslinking agent. Its structure was characterized by FT-IR, which indicated that the IPN was formed. The films were studied by swelling, weight loss with time, and release of coenzyme A (CoA). It was found that the IPN films were sensitive to pH and ionic strength of the medium. The cumulative release rate of CoA decreased with CoA loading content, ionic strength or crosslinking agent increasing. The composition of the IPN films and pH of release medium also had significant effect on the release of CoA. The differences in the rates and amounts of released CoA may be attributed to the swelling behavior, the degradation of films, and interaction between drug molecule and polymer matrix. These results suggested CS/CM-CS IPN films could be used as drug delivery carrier.     

葡萄糖敏感苯硼酸基高分子纳米药物传输体系

近年来,智能葡萄糖敏感自调式药物传递系统备受关注。这种智能药物释放系统能够模拟胰腺分泌胰岛素的生理模式而精准调控药物释放并控制血糖水平,在糖尿病治疗中具有良好的应用前景。其中,苯硼酸(PBA)功能化的葡萄糖敏感高分子纳米载体成为近年来的研究热点之一。该类材料具有体系稳定、可长期储存、可逆的葡萄糖敏感性能等优势。根据响应因素不同,葡萄糖敏感药物传递系统可分为pH响应、温度响应和光响应等类型。本文重点介绍了基于PBA的葡萄糖敏感高分子纳米药物载体的发展过程、性能和应用,并对该领域的发展前景进行了展望。