Protease-activated indocyanine green nanoprobes for intraoperative NIR fluorescence imaging of primary tumors.

Tumor-targeted fluorescent probes in the near-infrared spectrum can provide invaluable information about the location and extent of primary and metastatic tumors during intraoperative procedures to ensure no residual tumors are left in the patient's body. Even though the first fluorescence-guided surgery was performed more than 50 years ago, it is still not accepted as a standard of care in part due to the lack of efficient and non-toxic targeted probes approved by regulatory agencies around the world. Herein, we report protease-activated cationic gelatin nanoparticles encapsulating indocyanine green (ICG) for the detection of primary breast tumors in murine models with high tumor-to-background ratios.

Single intranasal administration of 17β-estradiol loaded gelatin nanoparticles confers neuroprotection in the post-ischemic brain.

Globally, ischemic stroke is a leading cause of death and adult disability. Previous efforts to repair damaged brain tissue following ischemic events have been hindered by the relative isolation of the central nervous system. We have developed a gelatin nanoparticle-mediated intranasal drug delivery system as an efficient, non-invasive method for delivering 17β-estradiol (E2) specifically to the brain, enhancing neuroprotection, and limiting systemic side effects.

Sustained exenatide delivery via intracapsular microspheres for improved survival and function of microencapsulated porcine islets.

The ability of glucagon-like peptide-1 analogs to enhance glucose-dependent insulin secretion and to inhibit β cell apoptosis could be of potential benefit for islet transplantation. In this study, we investigated the effect of sustained local delivery of exenatide, a synthetic exendin-4, on the in vitro viability and function of encapsulated porcine islets. Prior to encapsulation, we fabricated exenatide-loaded poly(latic-co-glycolic acid) microspheres, and investigated their release behavior with different initial drug-loading amounts.

Improved survival of anchorage-dependent cells in core-shell hydrogel microcapsules via co-encapsulation with cell-friendly microspheres.

In this study, we investigated the effect of intracapsular environment on the survival of anchorage-dependent cells (ADCs) encapsulated in alginate microcapsules with three different core structures, i.e. liquid, semi-liquid and microsphere-encapsulating semi-liquid core, using NIH 3T3 fibroblasts as an ADC model.

Acute effects of aerobic stretching, health and happiness improving movement exercise on cortical activity of children.

Acute high-intensity physical exercise is known to improve cognitive performance of children, including those with attention-deficit/hyperactivity disorder (ADHD). In this work, we investigated the acute effect of an aerobic stretching and moderate-intensity, health and happiness improving movement (HHIM) exercise on the cortical activity of children with and without ADHD using electroencephalography (EEG). Children aged 12 to 14 yr with combined-type ADHD and age-matched healthy controls participated in the study, performing two individual movements (n=79, 35 controls) and a single exercise bout (n=45, 18 controls).

Robust neuroprotective effects of intranasally delivered iNOS siRNA encapsulated in gelatin nanoparticles in the postischemic brain.

The therapeutic efficacy of intranasal iNOS siRNA delivery was investigated in the postischemic rat brain after encapsulating on in gelatin nanoparticles (GNPs; diameter 188.0 ± 60.9 nm) cross-linked with 0.

Gelatin nanoparticles enhance the neuroprotective effects of intranasally administered osteopontin in rat ischemic stroke model.

As a leading cause of death and adult disability, ischemic stroke requires the development of non-invasive, long-acting treatments. Osteopontin (OPN) is an endogenous protein shown to have neuroprotective effects in the post-ischemic brain of rats when administered through the non-invasive, intranasal pathway. Previously, gelatin microspheres (GMSs) have been shown to enhance the neuroprotective effects of OPN when used as a carrier during instrastriatal administration, but GMSs are generally too large to enter the brain parenchyma following intranasal administration.

Biodegradable gelatin microspheres enhance the neuroprotective potency of osteopontin via quick and sustained release in the post-ischemic brain.

Gelatin microspheres (GMSs) are widely used as drug carriers owing to their excellent biocompatibilities and toxicologically safe degradation products. The drug release profile is easily tailored by controlling the cross-linking density and surface-to-volume ratio, i.e.

Controlled release of Pantoea agglomerans E325 for biocontrol of fire blight disease of apple.

Microencapsulation and controlled release of the biocontrol agent Pantoea agglomerans strain E325 (E325), an antagonist to the bacterial plant pathogen Erwinia amylovora that causes fire blight, a devastating disease of apple and pear, have been investigated. Uniform core-shell alginate microcapsules (AMCs), 60-300 μm in diameter, were fabricated to encapsulate E325 within the core, along with nutrients, to preserve viability and promote proliferation. Controlled release of E325 was achieved by separately adjusting alginate concentrations in the shell and core solutions, and by modifying the AMC size.

Integration of type II nanorod heterostructures into photovoltaics.

High-quality epitaxial interfaces and delicate control over shape anisotropy make nanorod heterostructures (NRHs) with staggered band offsets efficient in separating and directing photogenerated carriers. Combined with versatile and scalable wet chemical means of synthesis, these salient features of NRHs are useful for improving both the performance and the cost-effectiveness of photovoltaics (PVs). However, inefficient carrier transport and extraction have imposed severe limitations, outweighing the benefits of enhanced charge separation.

The effect of biodegradable gelatin microspheres on the neuroprotective effects of high mobility group box 1 A box in the postischemic brain.

High mobility group box 1 (HMGB1) is a family of endogenous molecules that is released by necrotic cells and causes neuronal damages by triggering inflammatory processes. In the cerebral ischemic brain, sustained and regulated suppression of HMGB1 has been emerged as a therapeutic means to grant neuroprotection. HMGB1 consists of two HMG boxes (A and B) and an acidic C-terminal tail, and the A box peptide antagonistically competes with HMGB1 for its receptors.

Modeling of small-molecule release from crosslinked hydrogel microspheres: effect of crosslinking and enzymatic degradation of hydrogel matrix.

A diffusion-based model describing the drug release from a charged hydrogel (gelatin) microsphere undergoing enzymatic degradation is presented. The model elucidates the effect of glutaraldehyde, a crosslinking agent, on the release profile in terms of the initial drug distribution, diffusivity of the drug, degradation rate of gelatin and its ability to form polyionic complex with the drug. The model was validated by comparing with in vitro release of trypan blue, an acidic model drug, from basic gelatin microspheres.

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.

Monodisperse gelatin microspheres as a drug delivery vehicle: release profile and effect of crosslinking density.

Uniform gelatin microspheres (GMS) of a wet size of 100 microm in diameter were fabricated by the electric field assisted precision particle fabrication (E-PPF) method and crosslinked with different glutaraldehyde (GA) concentrations to study the effect of the crosslinking density on drug release. The drug release profiles of the crosslinked GMS were studied along with the intraparticle drug distribution and the particle degradation characteristics. Due to the concentration gradient of GA along the diffusion path into the GMS, the crosslinking density is higher on the GMS surface, making it less susceptible to degradation.

Macromolecule release from monodisperse PLG microspheres: control of release rates and investigation of release mechanism.

Novel macromolecular therapeutics such as peptides, proteins, and DNA are advancing rapidly toward the clinic. Because of typically low oral bioavailability, macromolecule delivery requires invasive methods such as frequently repeated injections. Parenteral depots including biodegradable polymer microspheres offer the possibility of reduced dosing frequency but are limited by the inability to adequately control delivery rates.

Uniform biodegradable hydrogel microspheres fabricated by a surfactant-free electric-field-assisted method.

Uniform biodegradable hydrogel microspheres (HMS) with precisely controlled size have been fabricated using an electric-field-assisted precision particle fabrication technique. Particle agglomeration was prevented by charging the hydrogel drops and allowing Coulomb repulsion to separate them. As a result, surfactant-free and non-toxic particle fabrication was possible and the resulting microspheres were most suitable for biomedical and food-related applications.

Monodisperse liquid-filled biodegradable microcapsules.

Purpose: Encapsulation of liquids into biodegradable polymer microcapsules has been a challenging task due to production limitations stemming from solution viscosity, phase stabilization, molecular localization, and scalable production. We report an extension of Precision Particle Fabrication (PPF) technology for the production of monodisperse liquid-filled microcapsules containing an oil or aqueous core and contrast these results to double-walled microspheres.

Materials And Methods: PPF technology utilizes a coaxial nozzle to produce a liquid core jet surrounded by a polymer annular jet, which is further encompassed by a non-solvent carrier stream, typically 0.

Small-molecule release from poly(D,L-lactide)/poly(D,L-lactide-co-glycolide) composite microparticles.

Addition of biodegradable polymer shells surrounding polymeric, drug-loaded microparticles offers the opportunity to control drug release rates. A novel fabrication method was used to produce microparticles with precise control of particle diameter and the thickness of the polymer shell. The effect of shell thickness on release of a model drug, piroxicam, has been clearly shown for 2- to 15-microm thick shells of poly(D,L-lactide) (PDLL) surrounding a poly(D,L-lactide-co-glycolide) (PLG) core and compared to pure PLG microspheres loaded with piroxicam.

In vitro degradation of polyanhydride/polyester core-shell double-wall microspheres.

Double-wall microspheres (DWMS), comprising distinct polymer core and shell phases, are useful and interesting for controlled-release drug delivery. In particular, the presence of a surface-eroding polymer core may be expected to limit water penetration and, therefore, delay degradation of the core phase and drug release. In this study, solid microspheres and DWMS were fabricated using a surface-eroding polymer (poly[1,6-bis(p-carboxyphenoxy)hexane]; PCPH) and a bulk-eroding polymer (poly(D,L-lactide-co-glycolide); PLG).

Controlling surface nano-structure using flow-limited field-injection electrostatic spraying (FFESS) of poly(D,L-lactide-co-glycolide).

Improved control of surface micro- and nano-structure may lead to enhanced performance of degradable biomedical devices such as surgical dressings, vascular grafts, tissue engineering scaffolds, sutures, and structures for guided tissue regeneration. An electrohydrodynamic method called flow-limited field-injection electrostatic spraying (FFESS) has been developed as an improved technique for the controlled deposition of polymeric material. Injecting charge using a nano-sharpened tungsten needle in a process called field ionization can efficiently induce an ionic state in a solution of poly(D,L-lactide-co-glycolide) increasing its capacity to carry charge.

Microsphere size, precipitation kinetics and drug distribution control drug release from biodegradable polyanhydride microspheres.

A thorough understanding of the factors affecting drug release mechanisms from surface-erodible polymer devices is critical to the design of optimal delivery systems. Poly(sebacic anhydride) (PSA) microspheres were loaded with three model drug compounds (rhodamine B, p-nitroaniline and piroxicam) with a range of polarities (water solubilities). The drug release profiles from monodisperse particles of three different sizes were compared to release from polydisperse microspheres.