Liposomes as a Novel Ocular Delivery System for Brinzolamide: In Vitro and In Vivo Studies.

The objective of this study was to investigate the potential of liposomes as an ophthalmic delivery system for brinzolamide (Brz) to enhance the local glaucomatous therapeutic effect. The liposomes of Brz (Brz-LPs) were produced by the thin-film dispersion method with a particle size of 84.33 ± 2.02 nm and an entrapment efficiency of 98.32 ± 1.61%. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) analysis proved that Brz was successfully entrapped into Brz-LPs. Brz-LPs displayed a biphasic release pattern in vitro with burst release initially and sustained release afterwards. The corneal permeability was measured using modified Franz-type diffusion cells, and Brz-LPs showed 6.2-fold increase in the apparent permeability coefficient when compared with the commercial available formulation (B rz-Sus). Moreover, Brz-LPs (1 mg/mL Brz) showed a more sustained and effective intraocular pressure reduction (5-10 mmHg) than Brz-Sus (10 mg/mL Brz) in white New Zealand rabbits. Therefore, Brz-LPs were a hopeful formulation of Brz for glaucoma treatment and worthy of further investigation.

Dual agent loaded PLGA nanoparticles enhanced antitumor activity in a multidrug-resistant breast tumor eenograft model.

Multidrug-resistant breast cancers have limited and ineffective clinical treatment options. This study aimed to develop PLGA nanoparticles containing a synergistic combination of vincristine and verapamil to achieve less toxicity and enhanced efficacy on multidrug-resistant breast cancers. The 1:250 molar ratio of VCR/VRP showed strong synergism with the reversal index of approximately 130 in the multidrug-resistant MCF-7/ADR cells compared to drug-sensitive MCF-7 cells. The lyophilized nanoparticles could get dispersed quickly with the similar size distribution, zeta potential and encapsulation efficiency to the pre-lyophilized nanoparticles suspension, and maintain the synergistic in vitro release ratio of drugs. The co-encapsulated nanoparticle formulation had lower toxicity than free vincristine/verapamil combinations according to the acute-toxicity test. Furthermore, the most effective tumor growth inhibition in the MCF-7/ADR human breast tumor xenograft was observed in the co-delivery nanoparticle formulation group in comparison with saline control, free vincristine, free vincristine/verapamil combinations and single-drug nanoparticle combinations. All the data demonstrated that PLGANPs simultaneously loaded with chemotherapeutic drug and chemosensitizer might be one of the most potential formulations in the treatment of multidrug-resistant breast cancer in clinic.

PEGylated hyaluronidase/NIR induced drug controlled release system for synergetic chemo-photothermal therapy of hepatocellular carcinoma.

In recent years, cancer treatment has been facing the challenge of increasing antitumor efficiency and avoiding severe adverse effects simultaneously. In this study, we designed a controlled release drug delivery system, doxorubicin (Dox)-loaded and hyaluronic acid (HA)-modified PEGylated gold nanocages (AuNCs), which was designated as PEG-HAn-AuNCs/Dox (n represented 10n HA repeating units were modified on each AuNC). In this system, AuNCs were applied as the photothermal cores, Dox was employed as the model drug, HA was applied as the tumor-microenvironment responsive switch to achieve controlled release, and poly (ethylene glycol) (PEG) was used as the stealth polymer to prolong systemic circulation time. Firstly, we evaluated the physical and chemical properties of the PEG-HAn-AuNCs/Dox with different ratios of HA to AuNC and found that PEG-HA4-AuNCs/Dox was the optimal. Secondly, PEG-HA4-AuNCs/Dox revealed the feature of controlled release, namely, the drug release was triggered by hyaluronidase (HAase) and accelerated by the acidic pH and near-infrared (NIR) irradiation. And then PEG-HA4-AuNCs/Dox could be effectively delivered to a cultured SMMC-7721 cell line in vitro and the tumor tissues of the subcutaneous mouse models of hepatocellular carcinoma (HCC) in vivo. Finally, the results demonstrated the synergetic therapy, namely the combination of chemotherapy and photothermal therapy (PTT) (defined as chemo-photothermal therapy) mediated by PEG-HA4-AuNCs/Dox, could efficiently inhibit the tumor growth both in vitro and in vivo. Therefore, the advantages of PEG-HA4-AuNCs/Dox endowed it as a great potential candidate for HCC treatment.

Gene Therapy and Photothermal Therapy of Layer-by-Layer Assembled AuNCs /PEI/miRNA/ HA Nanocomplexes.

BACKGROUND: MicroRNA (miRNA) therapy, which was widely considered to treat a series of cancer, has been confronted with numerous obstacles to being delivered into target cells because of its easy biodegradation and instability. METHODS: In this research, we successfully constructed 11-mercaptoundecanoic acid modified gold nanocages (AuNCs)/polyethyleneimine (PEI)/miRNA/hyaluronic acid (HA) complexes (abbreviated as AuNCs/PEI/miRNA/HA) using a layer-by-layer method for target-specific intracellular delivery of miRNA by HA receptor mediated endocytosis. RESULTS: The results of UV spectra, hydrodynamic diameter and zeta potential analyses confirmed the formation of AuNCs/PEI/ miRNA/HA complex with its average particle size of ca. 153 nm and surface charge of ca. -9.43 mV. Next, we evaluated the antitumor effect of the nanocomplex mediated by the combination of gene therapy and photothermal therapy (PTT) against hepatocellular carcinoma (HCC) in vitro. CONCLUSION: Our experimental results indicated that the AuNCs/PEI/miRNA/HA complex effectively delivered miRNA to the target cells and its antitumor effect was significantly enhanced by the combination of gene therapy and photothermal therapy. In addition, anti-miR-181b could promote Bel-7402 cell arrest in S phase and improve TIMP-3 mRNA expression. All these results suggested that AuNCs/PEI/miRNA/HA gene delivery system with combination of gene therapy and photothermal therapy might be exploited for HCC treatment.

TPGS modified nanoliposomes as an effective ocular delivery system to treat glaucoma.

The aim of this study is to investigate the potential of D-alpha-tocopheryl poly (ethylene glycol 1000) succinate (TPGS) modified nanoliposomes as an ophthalmic delivery system of brinzolamide (Brz) for glaucoma treatment. The Brz loaded nanoliposomes containing TPGS (T-LPs/Brz) were firstly developed by a thin-film dispersion method. The average particle size was 96.87 ±â€¯4.43 nm. The entrapment efficiency of the Brz was 95.41 ±â€¯3.03% and the drug loading was 4.00 ±â€¯0.13%. T-LPs/Brz exhibited obvious sustained release of Brz; in stark contrast to the normal liposomes of Brz (LPs/Brz) and the commercial formulation AZOPT® (Brz ophthalmic suspension, Brz-Sus). Enhanced trans-corneal transport of Brz was achieved with T-LPs/Brz. Compared with both Brz-Sus and LPs/Brz, the apparent permeability coefficient (Papp) of T-LPs/Brz was 10.2 folds and 1.38 folds higher, respectively. Moreover, T-LPs/Brz extended the cornea residence of Brz. White New Zealand rabbits treated with T-LPs/Brz had 3.18 folds and 1.57 folds Brz concentration 2 h after treatment than Brz-Sus and LPs/Brz, respectively. Further pharmacodynamic studies showed that T-LPs/Brz maintained an effective intraocular pressure (IOP) reduction from 3 h to 11 h after administration, while Brz-Sus and LPs/Brz presented effective IOP decreases from 3 h to 6 h and 3 h to 8 h respectively. The preliminary safety evaluation demonstrated that T-LPs/Brz had no significant side effects; specifically, no cornea damage and eye irritation. All the results indicated that TPGS modified nanoliposomes were a promising ocular delivery carriers for Brz to treat glaucoma. As such, T-LPs/Brz might be worthy of further translational study.

[Rat dental papilla cell culture with nanometer-HAP in vitro].

OBJECTIVE: To determine the effects of nano-hydroxyapatite(nano-HAP)on the proliferation and activity of rat dental papilla cells(RDPCs)in vitro, and to evaluate the feasibility of using nano-hydroxyapatite(nano-HAP)as dental papilla cell scaffold in dental tissue engineering. METHODS: RDPCs cultured with the porous nano-HAP in vitro served as the experimental group, and the routine culture of RDPCs in flasks served as the control. Scanning electronic microscope was used to observe the growth and adherence of the RDPCs to nano-HAP. Cell proliferation, cellular protein content, and alkaline phosphatase(ALP) were detected to assess the cellular activities. RESULTS: RDPCs proliferated well, and adhered to the outer and inner surface of the nano-HAP scaffold. Compared with the control group, cells in the experimental group presented higher proliferation on 6 d and 8 d and higher cellular protein content on 6 d and 9 d. No significant difference was detected in the ALP activity in the 2 groups. CONCLUSION: RDPCs seeded into nano-HAP grow better and have more vigorous cellular activity, suggesting that nano-HAP has excellent biocompatibility with dental papilla cells, and it can serve as a promising scaffold for dental tissue engineering.

[Construction of tissue engineered gingiva with gingival epithelia and acellular dermal matrix].

OBJECTIVE: To culture human gingival epithelia in vitro, and to construct the tissue engineered gingiva with the acellular dermal matrix (ADM). METHODS: Human gingival epithelia were isolated from the gingival tissue, and the cells were cultured and seeded onto the surface of ADM. After 7 days of submerged incubation, an air-liquid interface culture was performed for 7, 14, and 21 days. The complex constructed above was taken for histological examination. RESULTS: Human gingival epithelia could proliferate well on the surface of ADM, and form multilayer structure. But the superficial epithelium was partially keratinized. CONCLUSION: Tissue engineered gingiva may be constructed with human gingival epithelia and ADM in vitro.

Comparative study of (Asp)7-CHOL-modified liposome prepared using pre-insertion and post-insertion methods for bone targeting in vivo.

Specific delivery of drugs to bone tissue is very challenging due to the architecture and structure of bone tissue. A seven-repeat sequence of aspartate, a representative bone-targeting oligopeptide, is preferentially used for targeted therapy for bone diseases. In this study, Asp7-cholesterol((Asp)7-CHOL) was synthesized and (Asp)7-CHOL-modified liposome loaded with doxorubicin (DOX) was successfully prepared using both pre-insertion (pre-L) and post-insertion (post-L) methods. The formulation was optimized according to particle size, zeta potential and the drug-loading efficiency of the liposome. In addition, the bone affinity of the (Asp)7-CHOL-modified liposome was evaluated using a hydroxyapatite (HA) absorption method. The results suggested that (Asp)7-CHOL-modified liposome show excellent HA absorption; pre-L showed slightly higher HA binding than post-L. However, post-L had a higher DOX entrapment efficiency than pre-L. In vivo imaging further demonstrated that pre-L showed a higher bone-targeting efficiency than post-L, which was consistent with in vitro results. In all, (Asp)7-CHOL-modified liposome showed excellent bone-targeting activity, suggesting their potential for use as a drug delivery system for bone disease-targeted therapies.

An injectable silk sericin hydrogel promotes cardiac functional recovery after ischemic myocardial infarction.

UNLABELLED: Acute myocardial infarction (MI) leads to morbidity and mortality due to cardiac dysfunction. Here we identify sericin, a silk-derived protein, as an injectable therapeutic biomaterial for the minimally invasive MI repair. For the first time, sericin prepared in the form of an injectable hydrogel has been utilized for cardiac tissue engineering and its therapeutical outcomes evaluated in a mouse MI model. The injection of this sericin hydrogel into MI area reduces scar formation and infarct size, increases wall thickness and neovascularization, and inhibits the MI-induced inflammatory responses and apoptosis, thereby leading to a significant functional improvement. The potential therapeutical mechanisms have been further analyzed in vitro. Our results indicate that sericin downregulates pro-inflammatory cytokines (TNF-α and IL-18) and chemokine (CCL2) and reduces TNF-α expression by suppressing the TLR4-MAPK/NF-κB pathways. Moreover, sericin exhibits angiogenic activity by promoting migration and tubular formation of human umbilical vessel endothelial cells (HUVECs). Also, sericin stimulates VEGFa expression via activating ERK phosphorylation. Further, sericin protects endothelial cells and cardiomyocytes from apoptosis by inhibiting the activation of caspase 3. Together, these diverse biochemical activities of sericin protein lead to a significant recovery of cardiac function. This work represents the first study reporting sericin as an effective therapeutic biomaterial for ischemic myocardial repair in vivo. STATEMENT OF SIGNIFICANCE: Intramyocardial biomaterial injection is thought to be a potential therapeutic approach to improve cardiac performance after ischemic myocardial infarction. In this study, we report the successful fabrication and in vivo application of an injectable sericin hydrogel for ischemic heart disease. We for the first time show that the injection of in situ forming crosslinked sericin hydrogel promotes heart functional recovery accompanied with reduced inflammatory responses, attenuated apoptosis and increased microvessel density in the infarcted hearts. Further, we reveal that the improvement in those aspects is ascribed to sericin protein's functional bioactivities that are comprehensively uncovered in this study. Thus, we identify sericin, a natural protein, as a biomaterial suitable for myocardial repair and demonstrate that the in vivo application of this injectable sericin hydrogel can be an effective strategy for treating MI.

A silk sericin/silicone nerve guidance conduit promotes regeneration of a transected sciatic nerve.

Peripheral nerve gap defects lead to significant loss of sensory or motor function. Tissue engineering has become an important alternative to nerve repair. Sericin, a major component of silk, is a natural protein whose value in tissue engineering has just begun to be explored. Here, the first time use of sericin in vivo is reported as a long-term implant for peripheral nerve regeneration. A sericin nerve guidance conduit is designed and fabricated. This conduit is highly porous with mechanical strength matching peripheral nerve tissue. It supports Schwann cell proliferation and is capable of up-regulating the transcription of glial cell derived neurotrophic factor and nerve growth factor in Schwann cells. The sericin conduit wrapped with a silicone conduit (sericin/silicone double conduits) is used for bridging repair of a 5 mm gap in a rat sciatic nerve transection model. The sericin/silicone double conduits achieve functional recovery comparable to that of autologous nerve grafting as evidenced by drastically improved nerve function and morphology. Importantly, this improvement is mainly attributed to the sericin conduit as the silicone conduit alone only produces marginal functional recovery. This sericin/silicone-double-conduit strategy offers an efficient and valuable alternative to autologous nerve grafting for repairing damaged peripheral nerve.

Effect of concentration and molecular weight of chitosan and its derivative on the free radical scavenging ability.

Chitosan is a biodegradable and biocompatible natural scaffold material, which has numerous applications in biomedical sciences. In this study, the in vitro antioxidant activity of chitosan scaffold material was investigated by the chemiluminescence signal generated from the hydroxyl radical (•OH) scavenging assay. The scavenging mechanism was also discussed. The results indicated that the free radical scavenging ability of chitosan scaffold material significantly depends on the chitosan concentration and shows interesting kinetic change. Within the experimental concentration range, the optimal concentration of chitosan was 0.2 mg/mL. The molecular weight of chitosan also attributed to the free radical scavenging ability. Comparison between chitosan and its derivative found that carboxymethyl chitosan possessed higher scavenging ability.

Aqueous synthesis of multidentate-polymer-capping Ag2Se quantum dots with bright photoluminescence tunable in a second near-infrared biological window.

A new strategy for fabricating water-dispersible Ag2Se quantum dots (QDs) is presented. A multidentate polymer (MDP) was synthesized and used as a capping agent for Ag2Se QDs. The MDP-capping Ag2Se QDs were synthesized in aqueous solution at room temperature, which are highly photoluminescent in a second near-infrared (NIR-II) biological window and possess good photostability. These readily prepared NIR-II fluorescent nanoprobes have great potential for biomedical applications, especially useful for in vivo imaging.

Single-step noninjection synthesis of highly luminescent water soluble Cu+ doped CdS quantum dots: application as bio-imaging agents.

Novel highly luminescent Cu(+) doped CdS quantum dots (QDs) were directly synthesized in aqueous phase through a facile single-step noninjection method. Due to their bright red fluorescence, ultrasmall size, and good biocompatibility, as-prepared CdS:Cu(+) QDs have potential as probes in bio-imaging.

Preparation and characterization of diazeniumdiolate releasing ethylcellulose films.

A monolayer and trilayer membrane configuration of ethylcellulose were doped with a new synthesized diazeniumdiolate GAGS/NO (glutaraldehyde modification of glucosamine/NO adduct) and DETA/NO as the NO donor species, which can be used for altering the time course of nitric oxide donor release and targeting it to tissues with which the polymers are in physical contact. The NO donor release profiles show that the average release rate of DETA/NO can be controlled from 0.2 to 9 x 10(-10)mol cm(-2) min(-1) for at least 7 day and up to 30 day under physiological condition. The average release rate of GAGS/NO is varied from 0.1 to 0.5 x 10(-10)mol cm(-2) min(-1) for up to 94 day. The trilayer configuration effectively eliminates the burst release in the initial stage, and notably increases the NO donor release time. The trilayer films of DETA/NO can release 5% of the total NO donors over 69 h. In comparison, the trilayer films of GAGS/NO only release 2.5% of the total NO donors over 69 h. The results suggest that this nitric oxide donor releasing polymer may hold considerable promise for reducing the risk of restenosis following angioplasty and other interventional procedures for vascular repair.