Dian Li

Stimuli-responsive biodegradable poly(methacrylic acid) based nanocapsules for ultrasound traced and triggered drug delivery system.

Ultrasound contrast agents (UCAs) have been investigated for echogenic intravenous drug delivery system. Due to the traditional UCAs with overlarge size (micro-scale), their reluctant accumulation in target organs and the instability have presented severe obstacles to the accurate response to the ultrasound and severely limited their further clinical application. Furthermore, elimination of drug carriers from the biologic system after their carrying out the diagnostic or therapeutic functions is one important aspect to be considered. The drug carriers with large sizes, avoiding renal filtration, will lead to increasing toxicity. In this present paper, we design and develop a new type of triple-stimuli responsive (ultrasound/pH/GSH) biodegradable nanocapsules, in which fill up with perfluorohexane, and the DOX-loaded PMAA with disulfide crosslinking forms the wall. These soft nanocapsules with uniform size of 300 nm can easily enter the tumor tissues via EPR effects. The PMAA shell has high DOX-loading content (36 wt%) and great drug loading efficiency (93.5%), the PFH filled can effectively enhance US imaging signal through acoustic droplet vaporization (ADV), ensuring diagnostic and image-guided therapeutic applications. What is more, the disulfide-crosslinked PMAA shell is biodegradable and thus safe for normal organisms. These merits enabled us optimize the balance of diagnostic, therapeutic and biodegradable functionalities in a multifunctional theranostic nanoplatform.

Benzoboroxole‐Functionalized Magnetic Core/Shell Microspheres for Highly Specific Enrichment of Glycoproteins under Physiological Conditions

Efficient enrichment of specific glycoproteins from complex biological samples is of great importance towards the discovery of disease biomarkers in biological systems. Recently, phenylboronic acid-based functional materials have been widely used for enrichment of glycoproteins. However, such enrichment was mainly carried out under alkaline conditions, which is different to the status of glycoproteins in neutral physiological conditions and may cause some unpredictable degradation. In this study, on-demand neutral enrichment of glycoproteins from crude biological samples is accomplished by utilizing the reversible interaction between the cis-diols of glycoproteins and benzoboroxole-functionalized magnetic composite microspheres (Fe3O4/PAA-AOPB). The Fe3O4/PAA-AOPB composite microspheres are deliberately designed and constructed with a high-magnetic-response magnetic supraparticle (MSP) core and a crosslinked poly(acrylic acid) (PAA) shell anchoring abundant benzoboroxole functional groups on the surface. These nanocomposites possessed many merits, such as large enrichment capacity (93.9 mg/g, protein/beads), low non-specific adsorption, quick enrichment process (10 min) and magnetic separation speed (20 s), and high recovery efficiency. Furthermore, the as-prepared Fe3O4/PAA-AOPB microspheres display high selectivity to glycoproteins even in the E. coli lysate or fetal bovine serum, showing great potential in the identify of low-abundance glycoproteins as biomarkers in real complex biological systems for clinical diagnoses.

Doxorubicin‐Conjugated Mesoporous Magnetic Colloidal Nanocrystal Clusters Stabilized by Polysaccharide as a Smart Anticancer Drug Vehicle

Fabrication of magnetic nanocarriers that demonstrate enhanced biocompatibility and excellent colloidal stability is critical for the application of magnetic-motored drug delivery, and it remains a challenge. Herein, a novel approach to synthesize mesoporous magnetic colloidal nanocrystal clusters (MMCNCs) that are stabilized by agarose is described; these clusters demonstrate high magnetization, large surface area and pore volume, excellent colloidal stability, enhanced biocompatibility, and acid degradability. The hydroxyl groups of agarose, which cover the surface of the magnetic nanocrystals, are modified with vinyl groups, followed by click reaction with mercaptoacetyl hydrazine to form the terminal hydrazide (-CONHNH(2)). The anticancer agent doxorubicin (DOX) is then conjugated to MMCNCs through a hydrazone bond. The resulting hydrazone is acid cleavable, thereby providing a pH-sensitive drug release capability. This novel carrier provides an important step towards the construction of a new family of magnetic-motored drug-delivery systems. The experimental results show that the release rate of DOX from the DOX-conjugated MMCNCs (MMCNCs-DOX) is dramatically improved at low pH (tumor cell: pH 4-5 in the late stage of endolysosome and pH 5-6 from the early to late endosome), while almost no DOX is released at neutral pH (blood plasma). The cell cytotoxicity of the MMCNCs-DOX measured by MTT assay exhibits a comparable antitumor efficacy but lower cytotoxicity for normal cell lines, when measured against the free drug, thus achieving the aim of reducing side effects to normal tissues associated with controlled drug release.

Peroxidase-Like Activity of Fe3O4@Carbon Nanoparticles Enhances Ascorbic Acid-Induced Oxidative Stress and Selective Damage to PC-3 Prostate Cancer Cells

Ascorbic acid (AA) is capable of inhibiting cancer cell growth by perturbing the normal redox state of cells and causing toxic effects through the generation of abundant reactive-oxygen species (ROS). However, the clinical utility of AA at a tolerable dosage is plagued by a relatively low in vivo efficacy. This study describes the development of a peroxidase-like composite nanoparticle for use in an AA-mediated therapeutic strategy. On the basis of a high-throughput, one-pot solvothermal approach, Fe3O4@C nanoparticles (NPs) were synthesized and then modified with folic acid (FA) on the surface. Particular focus is concentrated on the assessment of peroxidase-like catalytic activity by a chromogenic reaction in the presence of H2O2. The carbon shell of Fe3O4@C NPs contains partially graphitized carbon and thus facilitates electron transfer in the catalytic decomposition of H2O2, leading to the production of highly reactive hydroxyl radicals. Along with magnetic responsiveness and receptor-binding specificity, the intrinsic peroxidase-like catalytic activity of Fe3O4@C-FA NPs pronouncedly promotes AA-induced oxidative stress in cancer cells and optimizes the ROS-mediated antineoplastic efficacy of exogenous AA. In vitro experiments using human prostate cancer PC-3 cells demonstrate that Fe3O4@C-FA NPs serve as a peroxidase mimic to create hydroxyl radicals from endogenous H2O2 that is yielded in response to exogenous AA via an oxidative stress process. The usage of a dual agent leads to the enhanced cytotoxicity of PC-3 cells, and, because of the synergistic effect of NPs, the administrated dosage of AA is reduced markedly. However, because normal cells (HEK 293T cells) appear to have a higher capacity to cope with additionally generated ROS than cancer cells, the NP-AA combination shows little damage in this case, proving that selective killing of cancer cells could be achieved owing to preferential accumulation of ROS in cancer cells. A possible ROS-mediated mechanism is discussed to elucidate the pharmaceutical profile of the NP-AA agent. In general, this foundational study reveals that the peroxidase-like nanomaterials are applicable for modulating oxidative stress for the selective treatment of cancer cells by generating a high level of endogenous ROS.

Cancer therapy and fluorescence imaging using the active release of doxorubicin from MSPs/Ni-LDH folate targeting nanoparticles

Hierarchical structured nanomaterials with diverse functionality, such as magnetic susceptibility, stimuli-responsiveness, environmental sensing and biocompatibility, are highly sought after for biomedicine and biodetection alike. In this study, we designed and fabricated a new kind of multifunctional core/shell nanospheres as biodegradable targeted drug carriers, the controlled drug release progress and therapeutic effect were monitored in-situ by the fluorescent state of the cells. Firstly, the core/shell nanospheres with biodegradability were synthesized using magnetic supraparticles (MSPs) as core and the layered double hydroxide (LDH) as shell via a hydrothermal route, the reaction parameters were well investigated to obtain the desired structure of the LDH shell. The anti-cancer drug doxorubicin was modified with carboxyl group (DOX-COOH) and loaded in the shell of MSPs/LDH nanospheres via an anion-exchange intercalation. To endow the nanospheres with tumor-targeting capability, IDA (iminodiacetic acid)-modified folate was successfully immobilized onto the surface of LDH shell using chelating interaction. These nanospheres behaved as multifunctional carriers for targeted delivery of anti-cancer drug, doxorubicin (DOX), within Hela cells and thus, these nano-drugs exhibited clear cytotoxicity and inhibition toward Hela cells as compared to normal cell-lines of HEK 293T cells. Interestingly, after the internalization of these nano-drugs, there was a sharp contrast in illumination between the tumorous Hela cells and the normal HEK 293T cells, the acidic cytoplasm of Hela cell stimulated DOX-COOH in LDH shell quickly degraded into positive-charged DOX, and then rapidly escaped from the positive-charged intercalation of LDH shell by strong repulsive interaction, the released DOX rapidly lit up the whole tumor cells in a short time, but only very weak light was found in HEK 293T cells.

Magnetic drug carrier with a smart pH-responsive polymer network shell for controlled delivery of doxorubicin

A smart magnetic targeting drug carrier (MCNC/PAA) comprising an approximately 100 nm sized magnetic colloid nanocrystal cluster (MCNC) core and a pH-responsive cross-linked poly(acrylic acid) (PAA) shell is reported. The abundant carboxyl groups in the shell enable the resultant MCNC/PAA to easily load a large amount of doxorubicin (DOX) (up to 44.6%) via the strong interaction between the DOX and the carboxyl group in a neutral solution. Interestingly, a synergistic pH-responsive effect derived from the entrapped DOX and PAA network was found to effectively manipulate the drug releasing behavior at 37 °C. It was found that the premature release was highly restricted at a pH of 7.4, and upon reduction in pH from 7.4 to 5.0 or 4.0, a large amount of drug was rapidly released. Compared with the synthesized MCNC/PNIPAM, MCNC/PHEMA and MCNC/PDMAPMA nanocarriers, the MCNC/PAA was preferably suited to drug delivery. In addition, the composite nanocarriers could be tracked by magnetic resonance imaging (MRI). The cytotoxicity assay of MCNC/PAA to normal cells indicated that the composite nanospheres were biocompatible and suitable as drug carriers. Meanwhile, the DOX-loaded composite nanospheres had more potent cytotoxicity than free DOX to HeLa cells. These results clearly imply that the MCNC/PAA nanocarrier is a promising platform that can be applied to construct a smart drug delivery system with magnetic targeting and pH-stimulation, as well as tracking by MRI.

Fe3O4/PVIM-Ni2+ Magnetic Composite Microspheres for Highly Specific Separation of Histidine-Rich Proteins

Integration of the advantages of immobilized metal-ion affinity chromatography (IMAC) and magnetic microspheres is considered as an ideal pathway for quick and convenient separation of his-tagged proteins, but rare reports concern the natural histidine-rich proteins. In this article, a novel route was presented to fabricate magnetic microspheres composed of a high-magnetic-response magnetic supraparticle (Fe3O4) core and a Ni(2+)-immobilized cross-linked polyvinyl imidazole (PVIM) shell via reflux-precipitation polymerization. The unique as-prepared Fe3O4/PVIM-Ni(2+) microspheres possessed uniform flower-like structure, high magnetic responsiveness, abundant binding sites, and very easy synthesis process. Taking advantage of the pure PVIM-Ni(2+) interface and high Ni(2+) loading amount, the microspheres exhibited remarkable selectivity, excellent sensitivity, large enrichment capacity, and high recyclability in immobilization and separation of his-tagged recombinant proteins. More interestingly, it was found that the Fe3O4/PVIM-Ni(2+) microspheres also showed excellent performance for removal of the natural histidine-rich bovine serum albumin (BSA) from the complex real sample of fetal bovine serum due to the exposed histidine residues. Considering their multiple merits, this new type of Fe3O4/PVIM-Ni(2+) nanomaterial displays great potential in enriching low-abundant his-tagged proteins or removing high-abundant histidine-rich natural proteins for proteomic analysis.

Ultrafast hydrothermal synthesis of high quality magnetic core phenol-formaldehyde shell composite microspheres using the microwave method.

An ultrafast, facile, and efficient microwave hydrothermal approach was designed to fabricate magnetic Fe(3)O(4)/phenol-formaldehyde (PF) core-shell microspheres for the first time. The structure of the Fe(3)O(4)/PF core-shell microspheres could be well controlled by the in situ polycondensation of phenol and formaldehyde with magnetic Fe(3)O(4) clusters as the seeds in an aqueous solution without any surfactants. The effect of synthetic parameters, such as the feeding amounts of phenol, the dosages of formaldehyde, the reaction temperatures, and the microwave heating time, on the morphologies and sizes of the Fe(3)O(4)/PF microspheres were investigated in details. The phenol-formaldehyde shell is found to be evenly coated on Fe(3)O(4) clusters within 10 min of the irradiation. The as-prepared microspheres were highly uniform in morphology, and the method was found to allow the shell thickness to be finely controlled in the range of 10-200 nm. The properties of the composite microspheres were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetic analysis (TGA), Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The as-prepared Fe(3)O(4)/PF microspheres were monodisperse and highly dispersible in water, ethanol, N,N-dimethyformamide, and acetone, a beneficial quality for the further functionalization and applications of the Fe(3)O(4)/PF microspheres.

Folate-conjugated poly(N-(2-hydroxypropyl)methacrylamide-co-methacrylic acid) nanohydrogels with pH/redox dual-stimuli response for controlled drug release

Folate-conjugated poly(N-(2-hydroxypropyl)methacrylamide-co-methacrylic acid) nanohydrogels were facilely prepared via distillation–precipitation polymerization and subsequent folate modification. Due to the nanohydrogels being crosslinked with disulphide bonds, they could be easily degraded into short polymer chains in the presence of glutathione, which will be beneficial for easily discharging the nanohydrogels from the body. Doxorubicin (DOX), a clinical anti-cancer drug, was efficiently loaded in the nanohydrogels (up to 39.3 wt%) by the electrostatic interactions between the amine group in doxorubicin (DOX) and the carboxyl groups in the nanohydrogels at neutral conditions. The cumulative release profile of the DOX-loaded nanohydrogels showed a relatively low level of drug release (23 wt% in 48 h) at pH 7.4 and a quick release (over 95 wt% in 2 h) at pH 5.0 with reducing environment, exhibiting pH/redox dual-stimuli-responsive drug release. The dose-dependent cytotoxicity of the drug-loaded nanohydrogels was studied by the CCK-8 assay. The nanohydrogels possess many favourable merits of drug carriers, such as excellent biocompatibility, high drug loading capacity, minimal drug release under an extracellular condition, rapid drug release in response to the intracellular level of pH and reducing environment, and folate-mediated endocytosis, which endow them as great candidates for targeted delivery of anti-cancer drugs.

Selective Capture and Quick Detection of Targeting Cells with SERS-Coding Microsphere Suspension Chip.

Circulating tumor cells (CTCs) captured from blood fluid represent recurrent cancers and metastatic lesions to monitor the situation of cancers. We develop surface-enhanced Raman scattering (SERS)-coding microsphere suspension chip as a new strategy for fast and efficient capture, recovery, and detection of targeting cancer cells. Using HeLa cells as model CTCs, we first utilize folate as a recognition molecule to be immobilized in magnetic composite microspheres for capturing HeLa cells and attaining high capturing efficacy (up to 95%). After capturing cells, the composite microsphere, which utilizes a disulfide bond as crosslinker in the polymer shell and as a spacer for linking folate, can recycle 90% cells within 20 min eluted by glutathion solution. Taking advantage of the SERS with fingerprint features, we characterize captured/recovered cells with the unique signal of report-molecule 4-aminothiophenol through introducing the SERS-coding microsphere suspension chip to CTCs. Finally, the exploratory experiment of sieving cells shows that the magnetic composite microspheres can selectively capture the HeLa cells from samples of mixed cells, indicating that these magnetic composite microspheres have potential in real blood samples for capturing CTCs.