Polysaccharide-based Noncovalent Assembly for Targeted Delivery of Taxol.

The construction of synthetic straightforward, biocompatible and biodegradable targeted drug delivery system with fluorescent tracking abilities, high anticancer activities and low side effects is still a challenge in the field of biochemistry and material chemistry. In this work, we constructed targeted paclitaxel (Taxol) delivery nanoparticles composed of permethyl-ß-cyclodextrin modified hyaluronic acid (HApCD) and porphyrin modified paclitaxel prodrug (PorTaxol), through host-guest and amphiphilic interactions. The obtained nanoparticles (HATXP) were biocompatible and enzymatic biodegradable due to their hydrophilic hyaluronic acid (HA) shell and hydrophobic Taxol core, and exhibited specific targeting internalization into cancer cells via HA receptor mediated endocytosis effects. The cytotoxicity experiments showed that the HATXP exhibited similar anticancer activities to, but much lower side effects than commercial anticancer drug Taxol. The present work would provide a platform for targeted paclitaxel drug delivery and a general protocol for the design of advanced multifunctional nanoscale biomaterials for targeted drug/gene delivery.

Recycling gene carrier with high efficiency and low toxicity mediated by L-cystine-bridged bis(ß-cyclodextrin)s.

Constructing safe and effective gene delivery carriers is becoming highly desirable for gene therapy. Herein, a series of supramolecular crosslinking system were prepared through host-guest binding of adamantyl-modified low molecular weight of polyethyleneimine with L-cystine-bridged bis(ß-cyclodextrin)s and characterized by (1)H NMR titration, electron microscopy, zeta potential, dynamic light-scattering, gel electrophoresis, flow cytometry and confocal fluorescence microscopy. The results showed that these nanometersized supramolecular crosslinking systems exhibited higher DNA transfection efficiencies and lower cytotoxicity than the commercial DNA carrier gold standard (25 kDa bPEI) for both normal cells and cancer cells, giving a very high DNA transfection efficiency up to 54% for 293T cells. Significantly, this type of supramolecular crosslinking system possesses a number of enzyme-responsive disulfide bonds, which can be cleaved by reductive enzyme to promote the DNA release but recovered by oxidative enzyme to make the carrier renewable. These results demonstrate that these supramolecular crosslinking systems can be used as promising gene carriers.

A small-sized graphene oxide supramolecular assembly for targeted delivery of camptothecin.

A small-sized graphene oxide supramolecular assembly was obtained by the inclusion complexation of hyaluronated adamantane with ß-cyclodextrin and the π-stacking of graphene oxide with camptothecin, exhibiting an excellent stability in the serum environment and a higher inhibition effect toward malignant cells than a free drug.

Gadolinium complexes functionalized persistent luminescent nanoparticles as a multimodal probe for near-infrared luminescence and magnetic resonance imaging in vivo.

The development of multimodal nanoprobes that combined properties of near-infrared (NIR) fluorescence and magnetic resonance imaging (MRI) within a single probe is very important for medical diagnosis. The NIR-emitting persistent luminescent nanoparticles (PLNPs) are ideal for optical imaging owing to no need for in situ excitation, the absence of background noise, and deep tissue penetration. However, no PLNP based multimodal nanoprobes have been reported so far. Here, we report a novel multimodal nanoprobe based on the gadolinium complexes functionalized PLNPs (Gd(III)-PLNPs) for in vivo MRI and NIR luminescence imaging. The Gd(III)-PLNPs not only exhibit a relatively higher longitudinal relaxivity over the commercial Gd(III)-diethylenetriamine pentaacetic acid complexes but also keep the superlong persistent luminescence. The prepared Gd(III)-PLNPs multimodal nanoprobe offers great potential for MRI/optical imaging in vivo.

A dual-targeting upconversion nanoplatform for two-color fluorescence imaging-guided photodynamic therapy.

The targetability of a theranostic probe is one of the keys to assuring its theranostic efficiency. Here we show the design and fabrication of a dual-targeting upconversion nanoplatform for two-color fluorescence imaging-guided photodynamic therapy (PDT). The nanoplatform was prepared from 3-aminophenylboronic acid functionalized upconversion nanocrystals (APBA-UCNPs) and hyaluronated fullerene (HAC60) via a specific diol-borate condensation. The two specific ligands of aminophenylboronic acid and hyaluronic acid provide synergistic targeting effects, high targetability, and hence a dramatically elevated uptake of the nanoplatform by cancer cells. The high generation yield of (1)O2 due to multiplexed Förster resonance energy transfer between APBA-UCNPs (donor) and HAC60 (acceptor) allows effective therapy. The present nanoplatform shows great potential for highly selective tumor-targeted imaging-guided PDT.

Polysaccharide-gold nanocluster supramolecular conjugates as a versatile platform for the targeted delivery of anticancer drugs.

Through the high affinity of the ß-cyclodextrin (ß-CD) cavity for adamantane moieties, novel polysaccharide-gold nanocluster supramolecular conjugates (HACD-AuNPs) were successfully constructed from gold nanoparticles (AuNPs) bearing adamantane moieties and cyclodextrin-grafted hyaluronic acid (HACD). Due to their porous structure, the supramolecular conjugates could serve as a versatile and biocompatible platform for the loading and delivery of various anticancer drugs, such as doxorubicin hydrochloride (DOX), paclitaxel (PTX), camptothecin (CPT), irinotecan hydrochloride (CPT-11), and topotecan hydrochloride (TPT), by taking advantage of the controlled association/dissociation of drug molecules from the cavities formed by the HACD skeletons and AuNPs cores as well as by harnessing the efficient targeting of cancer cells by hyaluronic acid. Significantly, the release of anticancer drugs from the drug@HACD-AuNPs system was pH-responsive, with more efficient release occurring under a mildly acidic environment, such as that in a cancer cell. Taking the anticancer drug DOX as an example, cell viability experiments revealed that the DOX@HACD-AuNPs system exhibited similar tumor cell inhibition abilities but lower toxicity than free DOX due to the hyaluronic acid reporter-mediated endocytosis. Therefore, the HACD-AuNPs supramolecular conjugates may possess great potential for the targeted delivery of anticancer drugs.

Targeted polysaccharide nanoparticle for adamplatin prodrug delivery.

A series of conjugated hyaluronic acid particles (HAP), composed of a hydrophobic anticancer drug core and hydrophilic cyclodextrin/hyaluronic acid shell, were prepared through self-assembling and characterized by (1)H NMR titration, electron microscopy, zeta potential, and dynamic light-scattering experiments. The nanometer-sized HAP thus prepared was biocompatible and biodegradable and was well-recognized by the hyaluronic acid receptors overexpressed on the surface of cancer cells, which enabled us to exploit HAP as an efficient targeted delivery system for anticancer drugs. Indeed, HAP exhibited anticancer activities comparable to the commercial anticancer drug cisplatin but with lower side effects both in vitro and in vivo.

One-step solvothermal synthesis of targetable optomagnetic upconversion nanoparticles for in vivo bimodal imaging.

Bionanoparticles and nanostructures with high biocompatibility and stability, low toxicity, diversification of imaging modality, and specificity of targeting to desired organs or cells are of great interest in nanobiology and medicine. However, integrating all of these desired features into a single bionanoparticle, which can be applied to biomedical applications and eventually in clinical prediagnosis and therapy, is still a challenge. We herein report a facile one-step solvothermal approach to fabricate targetable and biocompatible ß-NaYF4:Yb,Gd,Tm upconversion nanoparticles (UCNPs) with bimodal-signals (near-infrared (NIR) fluorescence and magnetic resonance (MR) signals) using hyaluronic acid (HA) as a multifunctional molecule. The prepared UCNPs with low toxicity are successfully applied for in vitro and in vivo targeted tumor imaging. The developed biomimetic surface modification approach for the synthesis of biomolecule-guided multifunctional UCNPs holds great potential applications in medical diagnostics and therapy.

Functional near infrared-emitting Cr3+/Pr3+ co-doped zinc gallogermanate persistent luminescent nanoparticles with superlong afterglow for in vivo targeted bioimaging.

Near infrared (NIR)-emitting persistent luminescent nanoparticles (PLNPs) have great potential for in vivo bioimaging with the advantages of no need for in situ excitation, high signal-to-noise ratio, and deep tissue penetration. However, functional NIR-emitting PLNPs with long afterglow for long-term in vivo imaging are lacking. Here, we show the synthesis of NIR-emitting long-persistent luminescent nanoparticles (LPLNPs) Zn2.94Ga1.96Ge2O10:Cr(3+),Pr(3+) by a citrate sol-gel method in combination with a subsequent reducing atmosphere-free calcination. The persistent luminescence of the LPLNPs is significantly improved via codoping Pr(3+)/Cr(3+) and creating suitable Zn deficiency in zinc gallogermanate. The LPLNP powder exhibits bright NIR luminescence in the biological transparency window with a superlong afterglow time of over 15 days. A persistent energy transfer between host and Cr(3+) ion in the LPLNPs is observed and its mechanism is discussed. PEGylation greatly improves the biocompatibility and water solubility of the LPLNPs. Further bioconjugation with c(RGDyK) peptide makes the LPLNPs promising for long-term in vivo targeted tumor imaging with low toxicity.

A new ditopic ratiometric receptor for detecting zinc and fluoride ions in living cells.

The synthesis, characterization and ion binding properties of a new ditopic ratiometric receptor (1), based on 2-(4,5-dihydro-1H-imidazol-2-yl)phenol and crown ether moieties, have been described. The ditopic ratiometric receptor has been studied in sensing both F(-) and Zn(2+) ions, exhibiting different fluorescent colour changes from cyan green to blue/black observable by the naked eye under UV-light. The addition of Zn(2+) to the solution of 1 induced the formation of a 2 : 2 ligand-metal complex 1-Zn(2+), which displays a remarkable blue shift of the emission maxima of 1 from 455 nm to 400 nm due to the inhibition of excited-state intramolecular proton transfer (ESIPT) mechanism. The sensing processes were monitored by fluorescence/absorption titrations, and further confirmed by Job's plot and (1)H NMR titrations. The crystal structure of 1-Zn(2+) reveals that 1 binds Zn(2+) in four-coordinated modes. Furthermore, 1 is cell permeable and may be applied to detect trace Zn(2+) and F(-) during the development of a living organism.

Near infrared fluorescent trypsin stabilized gold nanoclusters as surface plasmon enhanced energy transfer biosensor and in vivo cancer imaging bioprobe.

The simplicity of the green-synthesized routine and the availability of surface modification of diverse bioactive molecules make noble metal nanostructures highly suitable as multifunctional biomaterials for biological and biomedical application. Here, we report the preparation of trypsin stabilized gold nanoclusters (try-AuNCs) with near-infrared fluorescence for biosensing heparin based on surface plasmon enhanced energy transfer (SPEET) and folic acid (FA) modified try-AuNCs for in vivo cancer bioimaging. The SPEET/try-AuNCs fluorescence biosensor was designed via heparin mediated energy transfer between try-AuNCs and cysteamine modified gold nanoparticles (cyst-AuNPs). The developed SPEET/try-AuNCs fluorescence biosensor allowed sensitive and selective detection of heparin with a linear range of 0.1-4.0 µg mL(-1) and a detection limit (3s) of 0.05 µg mL(-1). The relative standard deviation for eleven replicate detections of 2.5 µg mL(-1) heparin was 1.1%, and the recoveries of the spiked heparin in human serum samples ranged from 97% to 100%. In addition, folic acid was immobilized on the surface of try-AuNCs to ameliorate the specific affinity of AuNCs for tumors, and the near-infrared fluorescent FA-try-AuNCs were applied for in vivo cancer imaging of high folate receptor (FR) expressing Hela tumor. In vivo study of the dynamic behavior and targeting ability of FA-try-AuNCs probe to Hela tumor bearing mice and normal nude mice validated the high specific affinity of FA-try-AuNCs probe to FR positive tumors. The results show that the prepared try-AuNCs have great potential as multifunctional biomaterials for biosensing biomolecules with SPEET mode and in vivo cancer imaging with high targeting ability.

Fabrication of transferrin functionalized gold nanoclusters/graphene oxide nanocomposite for turn-on near-infrared fluorescent bioimaging of cancer cells and small animals.

Transferrin (Tf)-functionalized gold nanoclusters (Tf-AuNCs)/graphene oxide (GO) nanocomposite (Tf-AuNCs/GO) was fabricated as a turn-on near-infrared (NIR) fluorescent probe for bioimaging cancer cells and small animals. A one-step approach was developed to prepare Tf-AuNCs via a biomineralization process with Tf as the template. Tf acted not only as a stabilizer and a reducer but also as a functional ligand for targeting the transferrin receptor (TfR). The prepared Tf-AuNCs gave intense NIR fluorescence that can avoid interference from biological media such as tissue autofluorescence and scattering light. The assembly of Tf-AuNCs and GO gave the Tf-AuNCs/GO nanocomposite, a turn-on NIR fluorescent probe with negligible background fluorescence due to the super fluorescence quenching property of GO. The NIR fluorescence of the Tf-AuNCs/GO nanocomposite was effectively restored in the presence of TfR, due to the specific interaction between Tf and TfR and the competition of TfR with the GO for the Tf in Tf-AuNCs/GO composite. The developed turn-on NIR fluorescence probe offered excellent water solubility, stability, and biocompatibility, and exhibited high specificity to TfR with negligible cytotoxicity. The probe was successfully applied for turn-on fluorescent bioimaging of cancer cells and small animals.

Transplantation of autologous activated Schwann cells in the treatment of spinal cord injury: six cases, more than five years of follow-up.

Schwann cells (SCs) are the main glial cells of the peripheral nervous system, which can promote neural regeneration. Grafting of autologous SCs is one of the well-established and commonly performed procedures for peripheral nerve repair. With the aim to improve the clinical condition of patients with spinal cord injury (SCI), a program of grafting autologous activated Schwann cells (AASCs), as well as a series of appropriate neurorehabilitation programs, was employed to achieve the best therapeutic effects. We selected six patients who had a history of SCI before transplantation. At first, AASCs were obtained by prior ligation of sural nerve and subsequently isolated, cultured, and purified in vitro. Then the patients accepted an operation of laminectomy and cell transplantation, and no severe adverse event was observed in any of these patients. Motor and sensitive improvements were evaluated by means of American Spinal Injury Association (ASIA) grading and Functional Independence Measure (FIM); bladder and urethral function were determined by clinical and urodynamic examination; somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) were used to further confirm the functional recovery following transplantation. The patients were followed up for more than 5 years. All of the patients showed some signs of improvement in autonomic, motor, and sensory function. So we concluded that AASC transplantation might be feasible, safe, and effective to promote neurorestoration of SCI patients.

Construction of a graphene oxide based noncovalent multiple nanosupramolecular assembly as a scaffold for drug delivery.

A multiple supramolecular assembly, in which a folic acid-modified ß-cyclodextrin (1) acted as a target unit, an adamantanyl porphyrin (2) acted as a linker unit, and graphene oxide acted as a carrier unit, was successfully fabricated through non-covalent interactions and comprehensively investigated by means of UV/Vis, fluorescence, and X-ray photoelectron spectroscopies, and electron microscopy. Significantly, the graphene oxide unit could associate with the anticancer drug doxorubicin through π-π interactions, and the folic acid-modified ß-cyclodextrin unit could recognize the folic acid receptors in cancer cells. Owing to the cooperative contribution of these three units, the resulting multiple supramolecular assembly, after association with doxorubicin, exhibited better drug activity and much lower toxicity than free doxorubicin in vivo.

Combination of activated Schwann cells with bone mesenchymal stem cells: the best cell strategy for repair after spinal cord injury in rats.

AIM: We aim to explore the repair effect of combined cell therapy using activated Schwann cells (ASCs) and bone mesenchymal stem cells (BMSCs) in traumatic spinal cord injury (SCI) in rats. MATERIALS & METHODS: ASCs and BMSCs were used for combined transplantation to treat acute SCI in rats, both of which can be obtained from SCI patients. ASCs were obtained by prior ligation of saphenous nerve and BMSCs by flush of the marrow cavity with Dulbecco's modified Eagle's medium solution. Our experiment in vitro confirmed that ASCs promoted BMSCs to differentiate into mature neural cells. It also indicates that BMSCs hold the potential to repair CNS injury. ASCs and BMSCs were co-transplanted into the injured epicenter of spinal cord made by the New York University (NYU) impactor machine using a 10 g × 50 mm drop weight. Complete ASCs, BMSCs and Dulbecco's modified Eagle's medium were also transplanted in rats with SCI as a control. Recovery of rat's hindlimb function was serially evaluated by Basso, Beattie, Bresnahan locomotor rating scale and footprint analysis. Changes of neurological potential were recorded by nerve electrophysiologic test. Improvement in the microenvironment of the injured spinal cord was evaluated by hematoxylin and eosin staining, glial fibrillary acidic protein staining, biotinylated dextran amine anterograde tracing and electron microscopy. RESULTS: Using biotinylated dextran amine anterograde tracing, we demonstrated that there were more regenerative axons of corticospinal tract surrounding and passing through the injured cavity to the caudal cord in the ASC-BMSC co-graft group than those in the other three groups, and we also confirmed this further by quantitative analysis. Immunostaining for glial fibrillary acidic protein showed the smallest population of astrocytes in the injury epicenter in the ASC-BMSC group compared with the other three groups. Relatively complete myelin sheaths and organelles were found in the ASC-BMSC group compared with the other three groups under electron microscopy. CONCLUSION: Effective co-transplantation of ASCs and BMSCs promotes functional recovery in rats' hindlimbs and reduces the formation of glial scar, and remyelinates the injured axons as compared with the other three groups. This conclusion was also supported by the observation of immunohistochemistry staining and electron microscopy, suggesting the possible clinical application for the treatment of spinal injury.

Silica-coated S(2-)-enriched manganese-doped ZnS quantum dots as a photoluminescence probe for imaging intracellular Zn2+ ions.

Detection of intracellular Zn(2+) has gained great attention because of its biological significances. Here we show the fabrication of silica-coated S(2-)-enriched Mn-doped ZnS quantum dots (SiO(2)-S-Mn-ZnS QDs) by enriching S(2-) with a silica shell on the surface of Mn-doped ZnS QDs via a sol-gel process for imaging intracellular Zn(2+) ions. The developed probe gave a good linearity for the calibration plot (the recovered PL intensity of the SiO(2)-S-Mn-ZnS QDs against the concentration of Zn(2+) from 0.3 to 15.0 µM), excellent reproducibility (1.2% relative standard deviation for 11 replicate measurements of Zn(2+) at 3 µM), and low detection limit (3s; 80 nM Zn(2+)). The SiO(2)-S-Mn-ZnS QDs showed negligible cytotoxicity, good sensitivity, and selectivity for Zn(2+) in a photoluminescence turn-on mode, being a promising probe for photoluminescence imaging of intracellular Zn(2+).

Fluorescence resonance energy transfer inhibition assay for α-fetoprotein excreted during cancer cell growth using functionalized persistent luminescence nanoparticles.

Persistent-luminescence nanoparticles (PLNPs) are promising as a new generation of photoluminescent probes for detection of biomolecules and bioimaging. Here we report a fluorescence resonance energy transfer (FRET) inhibition assay for α-fetoprotein (AFP) excreted during cancer cell growth using water-soluble functionalized PLNPs based on Eu2+- and Dy3+-doped Ca1.86Mg0.14ZnSi2O7. Polyethyleneimine-coated PLNPs were conjugated with AFP-antibody-coated gold nanoparticles as a sensitive and specific persistent photoluminescence probe for detection of AFP in serum samples and imaging of AFP excreted during cancer cell growth. Such PLNPs do not contain toxic heavy metals. Their long-lasting afterglow nature allows detection and imaging without external illumination, thereby eliminating the autofluorescence and scattering light from biological matrixes encountered under in situ excitation.

Intraspinal cord graft of autologous activated Schwann cells efficiently promotes axonal regeneration and functional recovery after rat's spinal cord injury.

Basic research in spinal cord injury (SCI) has made great strides in recent years, and some new insights and strategies have been applied in promoting effective axonal regrowth and sprouting. However, a relatively safe and efficient transplantation technique remains undetermined. This study, therefore, was aimed to address a question of how to graft Schwann cells to achieve the best possible therapeutic effects. To clarify the issue, the rats were subjected to spinal cord injury at T10. Autologous activated Schwann cells (AASCs) were obtained by prior ligation of saphenous nerve and subsequently isolated and purified in vitro and then grafted into spinal cord-injured rats via three different routes (group I: intravenous, group II: intrathecal and group III: intraspinal cord). Neurologic function was serially evaluated by Basso, Beattie, Bresnahan locomotor rating scale and footprint analysis. We also evaluated the migration of the transplanted cells at 2 weeks after transplantation. Using biotinylated dextran amine (BDA) anterograde tracing, we demonstrated that more regenerative axons of corticospinal tract (CST) surrounding the injured cavity in group III than those in the other two groups, and we also confirmed it further by quantitative analysis. The microenvironment surrounding the injured spinal cord has been improved to the greatest extent in group III, as determined by immunohistological staining. Relatively complete myelin sheaths and more neurofilaments in axons were found in groups II and III than those in group I under electron microscopy. The results showed that intraspinal cord injection of AASCs promoted recovery of hindlimb locomotor function of injured rats more efficiently than the other grafting routes. In addition, intact myelin sheaths and sufficient neurofilaments in axons were not adequate for full functional recovery after SCI, suggesting that reestablishment of normal synaptic connection is indispensable. The findings in this study strongly suggest that transplantation of AASCs directly into the spinal cord may be one of the promising candidates for potential scaffold for injured spinal cord, and such strategy of transplantation of AASCs could be hopeful to treat patients with SCI.

Regeneration of spinal cord with cell and gene therapy.

OBJECTIVE: Transplantation of fetal spinal cord cells (FSCC) can promote regeneration of injured spinal cord, while Schwann cells (SC) and some growth factors have a similar effect. However, the synergistic effects and optimal combination of these modalities have not yet been evaluated. In the current study, the efficiency of cell therapy of FSCC and/or SC, with/without growth factors (nerve growth factor [NGF] and brain-derived neurotrophic factor [BDNF]) was examined, with the aim of establishing an optimized protocol for spinal cord injury. METHODS: One hundred and twenty adult rats were randomly divided into six groups with 20 rats in each group. One week after the thoracic spinal cord injury model had been created, the rats were treated with different therapeutic modalities: Dulbecco's modified Eagles medium (DMEM) in Group I, FSCC in Group II, FSCC plus SC in Group III, FSCC plus SC over-expressing NGF in Group IV, FSCC plus SC over-expressing BDNF in Group V, and FSCC plus SC over-expressing both NGF and BDNF in Group VI. Subsequently, the rats were subjected to behavioral tests once a week after injury, while histology, immunohistochemistry and electron microscopy were performed at one and three month post-operation. RESULTS: Both SC and FSCC promoted regeneration of spinal cord injury when used separately, while a combination of the two types of cell resulted in better recovery than either alone. Both growth factors (NGF and BDNF) enhanced the outcomes of cell therapy, while synergistic effects meant that a combination of each individual component (group VI) achieved the best results according to locomotion scale, histology and immunoreactivity in the injured cords. CONCLUSION: SC, NGF and BDNF can enhance the outcome of FSCC therapy, while the combination of FSC with SC, NGF and BDNF is possibly the optimal protocol for clinical treatment of acute spinal cord injury.