Narrow Results

Dobutamine (Dobu) is a widely utilized therapeutic agent for heart failure with emerging potential in oncology. However, its clinical application is constrained by rapid release, short half-life and associated toxicity. This study introduces a dual-polymer nanomicelle system employing Pluronic F127 and lignin to encapsulate Dobu, aiming to enhance its release profile, minimize cytotoxicity and improve therapeutic efficacy. Nanomicelles were synthesized using an oil-in-water emulsion method, achieving encapsulation efficiencies of 99% for F127 and 80% for lignin, along with a controlled drug release profile. This novel dual-polymer nanomicelle system achieves high encapsulation efficiency (99% for F127 versus 80% for lignin) and controlled release, significantly reducing the burst release observed with free Dobutamine. Release studies demonstrated that F127 and lignin nanomicelles significantly reduced burst release compared to free Dobu, extending release durations up to 7 h. Cytotoxicity assays using NIH/3T3 fibroblast cells revealed increased cell viability for encapsulated Dobu, with F127 nanomicelles showing superior biocompatibility. Additionally, in vitro antibacterial evaluations confirmed that the nanomicelles did not inhibit microbial growth, highlighting their suitability for sterile applications. These findings suggest that F127 and lignin-based nanomicelles provide a promising platform for safer, controlled Dobu delivery in cardiovascular and oncological therapies.

Imidacloprid is a neonicotinoids insecticide, which is important for the cash crops such as tomato, rape and so on. The conventional formulation does not only increase the loss of pesticide but also leads to environmental pollution. Controlled-release formulations of pesticide are highly desirable not only for attaining the most effective utilization of the pesticide, but also for reducing environmental pollution. Pesticide imidacloprid was incorporated in poly (styrene–diacetone crylamide)-based formulation to obtain controlled release properties, and the imidacloprid nanocontrolled release formulation was characterized by infrared (IR) and field emission scanning electron microscope (FESEM). Factors related to loading efficiency, swelling and release behaviors of the formulation were investigated. It showed that the loading efficiency could reach about 40% (w/w). The values for the diffusion exponent "n" were in the range of 0.31–0.58, which indicated that the release of imidacloprid was diffusion-controlled. The time taken for 50% of the active ingredient to be released into water, T₅₀, was also calculated for the comparison of formulations in different conditions. The results showed that the formulation with higher temperature and more diacetone crylamide had lower value of T₅₀, which means a quicker release of the active ingredient. This study highlighted some pieces of evidence that improved pesticide incorporation and slower release were linked to potential interactions between the pesticide and the polymer.

Mesoporous silica nanoparticles (MSNs) have gained attention worldwide due to their structural versatility for diverse applications in a number of frontier areas of sciences. The intrinsic chemical, textural and structural features of MSNs allow fabricating versatile multifunctional nanosystems. The present review provides an overview of the research progress in artificial and biological production of MSNs, their properties and various applications in cutting edge areas of sciences.

Photodynamic therapy is an emerging modality of cancer treatment based on the use of photosensitizing drugs, which accumulate selectively in tumor cells. Exposure to visible light induces local cytotoxic effects that lead selectively to tumor cell death in the irradiated region, thereby minimizing the risk and extension of unwanted secondary effects. One of the goals sought in the development of photodynamic therapy drugs is the selective targeting of tumor cells. As a general trend, the indiscriminate delivery of drugs is being increasingly substituted by the selective delivery to pathological tissues which can be achieved by embedding them into transporters that actively recognize differential factors of tumor cells and tissues as compared to healthy ones. Likewise, the chemical modification of the photosensitizers is a valid strategy to change the subcellular localization of the drug. The use of liposomes as transporters for targeted delivery of drugs has attracted particular attention during the last two decades. After a period characterized by the skepticism expressed by certain scientists in the field of drug delivery, interest in liposomes was rejuvenated by the introduction of fresh ideas from membrane biophysics.

In this report, mixed polymeric micelles (MPMs) system self-assembled from two kinds of cholesterol-grafted amphiphilic block copolymers cholesterol modified poly ($\beta$-amino esters)-grafted disulfide poly (ethylene glycol) methyl ether (PAE(-ss-mPEG)-$g$-Chol) and poly($\beta$-amino ester)-g-poly(ethylene glycol) methyl ether-cholesterol (PAE-$g$-mPEG-Chol) were prepared for drug delivery and controlled release with pH and redox-responsibilities. The self-assembly of two block copolymers was evaluated by measurement of critical micelle concentration (CMC) values using fluorescence spectroscopy. The hydrodynamic diameter, polydispersity index (PDI) and zeta-potential of MPMs in aqueous were recorded by dynamic light scattering (DLS) at different conditions. Doxorubicin (DOX) was efficiently encapsulated in the micellar core by the hydrophobic interaction. The drug loading content (LC) and encapsulation efficacy (EE) of MPMs with different formulations were evaluated. The DOX was released due to the swelling and disassembly of MPMs induced by low pH and high glutathione (GSH) concentrations. The in vitro results demonstrated that drug release rate and cumulative release were obviously dependent on pH values and reducing agents. The results showed that the MPMs could be the potential anticancer drug delivery carriers with pH/redox-triggered drug release profile.

Aceclofenac (AC)/hydroxypropyl-β-cyclodextrin (HP-β-CD) complex intercalated layered double hydroxides (LDHs) have been synthesized by reconstruction method. X-ray diffraction, Fourier transform infrared and thermal gravimetric analyses indicated a successful intercalation of AC/HP-β-CD complex into the LDHs gallery. The AC release properties were also studied in different pH values buffer solution. The results indicate that the AC/HP-β-CD intercalated LDH has a potential application in drug delivery agent.

To integrate pH/NIR dual-responsive drug release mechanisms with multimodal therapies for effective treatment of malignant tumors, hierarchical hydroxyapatite (HAp)/AuNR hybrid microspheres, consisting of a hollow HAp core and an AuNR shell, were facilely synthesized using phytic acid (IP6) as a sustainable template and phosphorus source. Urea served as the pore-forming agent and pH regulator during the synthesis process. The integration of AuNR into multifunctional HAp systems enabled NIR-responsive controllable drug release and photothermal ablation specifically at the tumorigenic site. The aggregation of AuNR within and outside the hybrid microspheres effectively hinders the release of doxorubicin hydrochloride (DOX) from the hollow HAp microspheres, mitigating the initial burst release and minimizing side effects. The results indicate that the h-HAp/AuNR hybrid exhibited remarkable drug loading efficiency (159.9$\mu$g ⋅ mg${}^{-1}$), with drug release exhibiting pH-dependent behavior due to the dissolution of HAp in acidic environments. Furthermore, MTT assays and fluorescence imaging demonstrate that DOX-loaded h-HAp/AuNR significantly enhance antitumor efficacy, achieving a cell survival rate of 12.3% at a concentration of 100$\mu$g ⋅ mL. This integrated system offers a promising approach for combined chemotherapeutic delivery and NIR photothermal therapy.

Nanotechnology has been extensively explored in the past decade to develop a myriad of functional nanostructures to facilitate the delivery of therapeutic and imaging agents for various medical applications. Liposomes and polymeric nanoparticles represent two primary delivery vehicles that are currently under investigation. While many advantages of these two particle platforms have been disclosed, some intrinsic limitations remain to limit their applications at certain extent. Recently, a new type of nanoparticle platform, named lipid–polymer hybrid nanoparticle, has been developed that combines the positive attributes of both liposomes and polymeric nanoparticles while excluding some of their shortages. This new nanoparticle consists of a hydrophobic polymeric core, a lipid shell surrounding the polymeric core, and a hydrophilic polymer stealth layer outside the lipid shell. In this review, we first introduce the synthesis and surface functionalization techniques of the lipid–polymer hybrid nanoparticle, followed by a review of typical characterization of the particles. We then summarize the current and potential medical applications of this new nanoparticle as a delivery vehicle of therapeutic and imaging agents. Finally we highlight some challenges faced in further developing this robust delivery platform.

Selective laser sintering (SLS), a rapid prototyping technology, was investigated for producing bone tissue engineering scaffolds. Completely biodegradable osteoconductive calcium phosphate (Ca-P)/poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) scaffolds were successfully fabricated via SLS using Ca-P/PHBV nanocomposite microspheres. In the SLS manufacturing route, the architecture of tissue engineering scaffolds (pore shape, size, interconnectivity, etc.) can be designed and the sintering process can be optimized for obtaining scaffolds with desirable porous structures and mechanical properties. SLS was also shown to be very effective in producing highly complex porous structures using nanocomposite microspheres. To render SLS-formed Ca-P/PHBV scaffolds osteoinductive, recombinant human bone morphogenetic protein-2 (rhBMP-2) could be loaded onto the scaffolds. For achieving a controlled release of rhBMP-2 from scaffolds, surface modification of Ca-P/PHBV scaffolds by gelatin entrapment and heparin immobilization was needed. The immobilized heparin provided binding affinity for rhBMP-2. Surface modified Ca-P/PHBV nanocomposite scaffolds loaded with rhBMP-2 enhanced the proliferation of human umbilical cord derived mesenchymal stem cells (hUCMSCs) and also their alkaline phosphatase activity. In in vivo experiments using a rabbit model, surface modified Ca-P/PHBV nanocomposite scaffolds loaded with rhBMP-2 promoted ectopic bone formation, exhibiting their osteoinductivity. The strategy of combining advanced scaffold fabrication, nanocomposite material, and controlled growth factor delivery is promising for bone tissue regeneration.

In light of the challenges along with the traditional intravenous administration of chemotherapeutics, injectable hydrogel-drug system emerges as a powerful tool for noninvasive and in situ controlled-release of drugs. Herein, we report a novel strategy of drug delivery system with pH responsive injectable hydrogels by taking advantages of two biomaterials. The first one is a pH sensitive polymer-drug (prodrug) conjugate, poly (ethylene glycol)–doxorubicin (MPEG–DOX) with hydrazone linkage. This prodrug interacted with a second biomaterial, α-cyclodextrin (α-CD) under mild conditions and subsequently formed the hydrogels in minutes with tunable stiffness. The gels showed a sustained release behavior dependent on the surrounding pH and released drugs effectively killed tumor cells (MCF-7). The quick cell uptake and efficient intracellular delivery of DOX were observed under a confocal microscope. This study thus provides a novel and simple drug encapsulation strategy to deliver poorly soluble drugs in situ for a potential targeted chemotherapy.

In recent years, 4D printing has gained increasing attention in the tissue engineering field since this advanced manufacturing platform can create stimulus-responsive structures, which can change their shapes, functions, and/or properties when appropriate external stimulus/stimuli is/are applied. A number of hydrogels with swellable/shrinkable abilities have been explored for 4D printing to fabricate different shape-morphing structures for tissue engineering. Among them, gelatin methacryloyl (GelMA) has been 4D printed, which can self-fold into microtubular structures. Currently, the self-folding ability of 4D printed GelMA hydrogels is mainly based on the different cross-linking degrees (which control and govern the swelling degrees) across the thickness of hydrogels. However, this strategy alone can only form self-folding GelMA tubes with diameters at the micrometer level and cannot create self-folding GelMA tubes with diameters at the millimeter level, which is mainly due to the insufficient internal force generated in 4D printed GelMA hydrogels when they are exposed to water. To overcome this limitation, this study has investigated a new strategy to fabricate self-folding GelMA tubes with large diameters at the millimeter level for tissue engineering applications. The new strategy introduced a cross-linking degree gradient across the GelMA plane in addition to its thickness by printing a second layer of strips on the first 4D printed GelMA film. In the aqueous environment, under the current fabrication condition, such bilayer GelMA hydrogels could self-fold into tubes of larger diameters up to 6mm. The in vitro release behavior of heparin incorporated into the 4D printed GelMA was also studied. It was shown that heparin release could be controlled by the GelMA concentration and heparin content in 4D printed GelMA. The 4D printed GelMA hydrogels with the improved self-folding ability and controlled release of a drug are promising for targeted tissue engineering applications.