Clinical Editor Research Articles

Succinated chitosan as a gene carrier for improved chitosan solubility and gene transfection

Chitosan (CHI), a linear polysaccharide, has been intensively studied as a nonviral gene delivery vector. The low physiological solubility of CHI has limited its gene transfection efficiency. Here we report the synthesis of different substitution degrees of succinated chitosans (CHI-succ) to increase water solubility. According to the proton nuclear magnetic resonance spectra, the degree of deacetylation of hydrolyzed CHI was roughly 88% and the degrees of succinylation in three CHI-succ polymers were approximately 5, 10, and 20%. Various weight ratios of CHI/DNA and CHI-succ/DNA polyplexes were prepared for gel electrophoresis retardation, particle size, zeta potential, and morphology studies. The results suggest that the plasmid DNA is readily entrapped at a CHI-succ/DNA weight ratio of 20; the sizes and zeta potentials were between 110 and 140 nm and ±1–5 mV, and the polyplexes exhibited low cytotoxicity against HEK 293T cells. CHI-succ with 5 and 10% degrees of substitution showed improved transfection efficiency as compared with nascent CHI. From the Clinical Editor Chitosan, a cationic polysacchride with gene therapy potential, has inherently poor water solubility, which is improved by partial succinylation according to this report. The new DNA/Chitosan polyplexes exhibit improved safety against HEK 293T cells.

Comparative structural and functional studies of nanoparticle formulations for DNA and siRNA delivery

The transfection efficiencies of 25-kDa branched polyethylenimine (B-PEI) and 22-kDa linear PEI (L-PEI) with both DNA and small interfering RNA (siRNA) were compared and correlated with their biophysical properties relating to complex formation, stability, and disassembly. L-PEI-DNA complexes transfected (5.18 × 10 8 relative luminescence units [RLU]/mg) around fivefold better than B-PEI-DNA complexes (0.95 × 10 8 RLU/mg), whereas B-PEI-siRNA complexes gave approximately 60% gene knockdown and L-PEI-siRNA complexes were inactive. Both B-PEI and L-PEI packaged DNA and siRNA to form positively charged nanoparticles; however, L-PEI nanoparticles were less stable than B-PEI nanoparticles, particularly with siRNA. The poor stability of L-PEI-siRNA complexes seemed to be the major factor contributing to an observed lack of cellular uptake and hence poor transfection. The more stable B-PEI-siRNA complexes, however, were bound, internalized, and detectable in the cytoplasm. These results highlight the importance of particle stability for efficient siRNA and plasmid delivery, while retaining the ability to readily dissociate within the cell. From the Clinical Editor Comparison of branched versus linear cationic polymers, i.e, polyethylenimine (PEI), were compared for their formation of condensed DNA and SiRNA complexes. Branched complexes were superior for transfection due to improved structural stability, making this PEI approach more likely to succeed as a nanotherapy.

Polymer nanoparticles containing tumor lysates as antigen delivery vehicles for dendritic cell–based antitumor immunotherapy

Encapsulation of tumor-associated antigens in polymer nanoparticles (NP) is a promising approach to enhance efficiency of antigen delivery for anti-tumor vaccines. Head and neck squamous carcinoma (HNSCC) cell lines were initially used to generate tumor-associated antigens (TAA)-containing poly (lactic-co-glycolic acid) (PLGA) NP; encapsulation efficiency and release kinetics were profiled. Findings were adopted to entrap fresh tumor lysate from five patients with advanced HNSCC. To test the hypothesis that NP enhance antigen presentation, dendritic cell (DC) produced from patient blood monocyte precursors were loaded with either the un-encapsulated or NP-encapsulated versions of tumor lysates. These were used to stimulate freshly-isolated autologous CD8+ T cells. In four of five patients, anti-tumor CD8+ T cells showed significantly increased immunostimulatory IFN-γ (p=0.071) or decreased immmunoinhibitory IL-10 production (p=0.0004) associated with NP-mediated antigen delivery. The observations represent an enabling step in the production of clinically-translatable, inexpensive, highly-efficient, and personalized polymer-based immunotherapy for solid organ malignancies. From the Clinical Editor Enhancing the antigen presentation may be a viable approach to increase the efficiency of tumor cell directed cytotoxicity via immune mechanisms. This study presents an example for this using head and neck cancer cell lines and nanotechnology-based encapsulated antigen presentation to dendritic cells. The observed CD8+ T-cell response was significantly enhanced. This method may pave the way to a highly efficient cancer cell elimination method with minimal to no toxicity.

Nanosuspension: a new vehicle for the improvement of the delivery of drugs to the ocular surface. Application to amphotericin B

Present limitations in the management of ophthalmic fungal infections include the inability to provide long-term extraocular drug delivery without compromising intraocular structures and/or systemic drug exposure. In the present study, the potential of Eudragit RS 100 nanoparticles (NPs) as a new vehicle for the improvement of the delivery of drugs to the ocular mucosa was investigated. Amphotericin B (AmB) was chosen as a model compound because of its potential usefulness for the treatment of fungal diseases. A solvent displacement technique was used to produce AmB-loaded Eudragit NPs. These NPs had a mean size range of 150–290 nm and a zeta potential of +19–28 mV. Even after 6 months of stability study, results were unchanged, indicating the good potential for ocular application. In vitro release studies revealed that a maximum amount of drug was released within 24 hours (60%). The results obtained from microbial assay showed that the antifungal activity of drug-loaded NPs was equal to or slightly lower than that of free-AmB solution. In vivo experiments showed that, following topical instillation of nanosuspension to a rabbit's eye there was no irritation. From these results we can conclude that Eudragit RS 100 nanosuspension may represent an efficacious vehicle to deliver the drug into the eye. From the Clinical Editor Amphotericin B encapsulated into Eudragit, a mildly cationic nanoparticle, was shown to have 6 month stability, release 60% of its drug payload in dissolution within 24 hours, and elicited no irritation when instilled into rabbit eyes. The concept is being considered for local ophthalmologic therapy of fungal disease.

Shell cross-linked and hepatocyte-targeting nanoparticles containing doxorubicin via acid-cleavable linkage

Hepatocyte-targeting and shell cross-linked nanoparticles with lactose moiety on the surface and doxorubicin (DOX) in the core were prepared from lactose-PEG-DOX conjugate. The process consists of the synthesis of a novel α-hydrazine- ω-propargyl poly(ethylene glycol) (PEG) with a double bond in the PEG backbone, followed by the bonding of a lactose molecule containing an azide group to the ω-end of PEG via “click” chemistry, and finally, the conjugation of DOX to the α-end of PEG via an acid-labile, hydrazone linkage. The resultant conjugate can be self-assembled into nanoparticles. Thiolated tri(ethylene glycol) was introduced into the shell of nanoparticles as a cross-linking agent. The release of DOX is more rapid from lactose-PEG-DOX at pH 5.0 than at pH 7.4. Fluorescent microscope studies suggest that the lactose-DOX nanoparticles are internalized by hepatoma cells through a lactose receptor–mediated mechanism, whereas the lactose-free nanoparticles are not endocytosed as rapidly as lactose-DOX nanoparticles. MTT assay also shows that lactose-DOX nanoparticles have a stronger inhibition against hepatoma cells than DOX nanoparticles and pure DOX. From the Clinical Editor In this basic science study, a highly efficient targeted doxorubicin delivery method to hepatocytes is presented.

C 60 fullerene-pentoxifylline dyad nanoparticles enhance autophagy to avoid cytotoxic effects caused by the β-amyloid peptide

Many studies have focused on the neuroprotective effects of C 60 fullerene-derived nanomaterials. The peculiar structure of C 60 fullerene, which is capable of “adding” multiple radicals per molecule, serves as a “radical sponge,” and it can be an effective antioxidant by reducing cytotoxic effects caused by intracellular oxidative stress. In this study, PEG-C 60-3, a C 60 fullerene derivative incorporating poly(ethylene glycol), and its pentoxifylline-bearing hybrid (PTX-C 60-2) were investigated against β-amyloid (Aβ) 25-35-induced toxicity toward Neuro-2A cells. PEG-C 60-3 and PTX-C 60-2 significantly reduced Aβ 25-35-induced cytotoxicity, with comparable activities in decreasing reactive oxygen species and maintaining the mitochondrial membrane potential. Aβ 25-35 treatment elicited adenosine monophosphate-activated protein kinase–associated autophagy. Cytoprotection by PEG-C 60-3 and PTX-C 60-2 was partially diminished by an autophagy inhibitor, indicating that the elicited autophagy and antioxidative activities protect cells from Aβ damage. PTX-C 60-2 was more effective than PEG-C 60-3 at enduring the induced autophagy. Our results offer new insights into therapeutic drug design using C 60 fullerene–PTX dyad nanoparticles against Aβ-associated diseases. From the Clinical Editor The neuroprotective effects of C60 fullerene-derived nanomaterials are known and thought to be related to their capacity of “absorbing” multiple free radicals. In this study, another interesting property is presented: they may enhance autophagy of beta-amyloid peptide, which could minimize the damaging effects of this peptide.

A new thermography-based approach to early detection of cancer utilizing magnetic nanoparticles theory simulation and in vitro validation

This work describes the utilization of tumor-specific magnetic nanoparticles together with an alternating magnetic field as a means to thermally mark a tumor so as to detect it using a thermal imaging system. Experiments were conducted using an in vitro tissue model, an inductive heating system, and an infrared camera. The thermal images, recorded by the infrared camera during the experiments, were analyzed using an algorithm that was developed as part of this work. The results show that small tumor phantoms (diameter of 0.5 mm) that were embedded under the surface of the tissue phantom (up to 14 mm below the surface) can be detected and located, indicating that the proposed method could potentially offer considerable advantages over conventional thermography and other methods for cancer early detection. Nevertheless, several issues should be clarified in future studies before the method can be offered for clinical use. From the Clinical Editor Tumor-specific magnetic nanoparticles exposed to an alternating magnetic field provide a method to thermally mark a tumor for detection using thermal imaging systems. In-vitro tissue model experiments demonstrated that tumor phantoms of 0.5mm up to 14mm below the surface can be detected and located, indicating that the proposed method could offer considerable advantages over conventional thermography.

Photothermolysis of glioblastoma stem-like cells targeted by carbon nanotubes conjugated with CD133 monoclonal antibody

CD133 + cells in glioblastoma (GBM) display cancer stem cell-like properties and have been considered as the culprit of tumor recurrence, justifying exploration of potential therapeutic modalities targeting CD133 + cancer stem-like cells (CSCs). For photothermolysis studies, GBM-CD133 + and GBM-CD133 – cells mixed with various ratios were challenged with single-walled carbon nanotubes (SWNTs) conjugated with CD133 monoclonal antibody (anti-CD133) and then irradiated with near-infrared laser light. Results show that GBM-CD133 + cells were selectively targeted and eradicated, whereas GBM-CD133 – cells remained viable. In addition, in vitro tumorigenic and self-renewal capability of GBM-CD133 + treated with localized hyperthermia was significantly blocked. Furthermore, GBM-CD133 + cells pretreated with anti-CD133-SWNTs and irradiated by near-infrared laser 2 days after xenotransplantation in nude mice did not exhibit sustainability of CSC features for tumor growth. Taken altogether, our studies demonstrated that anti-CD133-SWNTs have the potential to be utilized as a thermal-coupling agent to effectively target and destroy GBM CSCs in vitro and in vivo. From the Clinical Editor Glioblastoma remains one of the most notorious cancer from the standpoint of recurrence and overall resistance to therapy. CD133+ stem cells occur among GBM cells, and may be responsible for the huge recurrence risk. This paper discusses a targeted elimination method of these cells, which may enable more efficient therapy in an effort to minimize or prevent recurrence.

The how, when, and why of the aging signals appearing on the human erythrocyte membrane: an atomic force microscopy study of surface roughness

We recently developed an atomic force microscopy–based protocol to use the roughness of the plasma membrane of erythrocytes (red blood cells, RBCs) as a morphological parameter, independently from the cell shape, to investigate the membrane-skeleton integrity in healthy and pathological cells. Here we apply the method to investigate a complex physiological phenomenon, the RBCs aging, that plays a major role in the regulation of the RBCs' turnover. The aging, monitored morphologically and biochemically, has been accelerated and modulated by preventing oxidative stresses as well as the effects of proteases and divalent cations, and by artificially consuming the intracellular adenosine triphosphate. The collected data evidence that the progression of aging causes a drastic decrease of the measured roughness that is diagnostic of a progressive, adenosine triphosphate–dependent alteration of the membrane-skeleton properties. Finally, the degree of reversibility of such effects has been investigated as a function of aging time, enabling the detection of irreversible transformation in the RBCs' structure and metabolism. From the Clinical Editor An Atomic Force Microscopy-based protocol that uses the roughness of plasma membrane of erythrocytes as a morphological parameter to investigate membrane-skeleton integrity was applied to investigate red blood cell aging. The authors demonstrate that aging causes a decrease of the measured roughness, correlating with a progressive, ATP-dependent alteration of membrane-skeleton properties.

Magnetic resonance and fluorescence imaging of doxorubicin-loaded nanoparticles using a novel in vivo model

We report here the in vivo combined-modality imaging of multifunctional drug delivery nanoparticles. These dextran core–based stealth liposomal nanoparticles (nanosomes) contained doxorubicin, iron oxide for magnetic resonance imaging (MRI) contrast, and BODIPY for fluorescence. The particles were long-lived in vivo because of surface decoration with polyethylene glycol and the incorporation of acetylated lipids that were ultraviolet cross-linked for physical stability. We developed a rodent dorsal skinfold window chamber that facilitated both MRI and non-invasive optical imaging of nanoparticle accumulation in the same tumors. Chamber tumors were genetically labeled with DsRed-2, which enabled co-localization of the MR images, the red fluorescence of the tumor, and the blue fluorescence of the nanoparticles. The nanoparticle design and MR imaging developed with the window chamber were then extended to orthotopic pancreatic tumors expressing DsRed-2. The tumors were MR-imaged using iron oxide–dextran liposomes and by fluorescence to demonstrate the deep imaging capability of these nanoparticles. From the Clinical Editor In vivo combined-modality imaging of multifunctional drug delivery nanoparticles is discussed in this proof of principle paper.

Antioxidant idebenone-loaded nanoparticles based on chitosan and N-carboxymethylchitosan

Nanoparticles based on chitosan (Ch) and N-carboxymethylchitosan ( N-CMCh) cross-linked with tripolyphosphate (TPP) were developed by co-drying with idebenone in different polymer-to-drug ratios (1.3:1 to 16:1) with 20% (wt/wt) colloidal silicon dioxide and tripolyphosphate (0.2 mg/mL). At high ratios (8:1 and 16:1) the spray-dried powder showed spherical and dense particles with a size close to 1 μm, allowing almost complete drug coating by the polymeric system and a high efficiency of drug incorporation (>90% and >80%, for Ch and N-CMCh, respectively). The nanoparticles showed a 10-fold increase of drug stability in comparison with free drug and preserved antioxidant activity in vitro. Compared with the severely irritative free form of idebenone, the nanoparticle formulation showed decreased mucous membrane irritation. These results revealed the potential of Ch and N-CMCh nanoparticles as carriers for a hydrophobic and irritative drug such as idebenone for topical or nasal use. From the Clinical Editor Chitosan and N-carboxymethylchitosan nanoparticles have potential roles as carriers for hydrophobic and irritative drugs such as the antioxidant idebenone for topical or nasal use.

Preparation and characterization of ketoprofen-loaded solid lipid nanoparticles made from beeswax and carnauba wax

Solid lipid nanoparticles (SLNs) have been proposed as suitable colloidal carriers for delivery of drugs with limited solubility. Ketoprofen as a model drug was incorporated into SLNs prepared from a mixture of beeswax and carnauba wax using Tween 80 and egg lecithin as emulsifiers. The characteristics of the SLNs with various lipid and surfactant composition were investigated. The mean particle size of drug-loaded SLNs decreased upon mixing with Tween 80 and egg lecithin as well as upon increasing total surfactant concentration. SLNs of 75 ± 4 nm with a polydispersity index of 0.2 ± 0.02 were obtained using 1% (vol/vol) mixed surfactant at a ratio of 60:40 Tween 80 to egg lecithin. The zeta potential of these SLNs varied in the range of –15 to –17 (mV), suggesting the presence of similar interface properties. High drug entrapment efficiency of 97% revealed the ability of SLNs to incorporate a poorly water-soluble drug such as ketoprofen. Differential scanning calorimetry thermograms and high-performance liquid chromatographic analysis indicated the stability of nanoparticles with negligible drug leakage after 45 days of storage. It was also found that nanoparticles with more beeswax content in their core exhibited faster drug release as compared with those containing more carnauba wax in their structure. From the Clinical Editor Ketoprofen as model drug was incorporated into solid lipid nanoparticles, which have been proposed as suitable colloidal carriers for delivery of drugs with limited solubility. High drug entrapment efficiency, stability of nanoparticles with negligible drug leakage and fast drug release can be accomplished using this technology.

Nanoscale phase dynamics of the normal tear film

The tear film is a dynamic multilayered structure. The interactions and the interfacial dynamics between the layers that occur during a blink cycle must be such that they allow for maintenance of a stable tear film. Attempts to understand these dynamics have been limited by the techniques and biomarkers used. Quantum dots (qdots) offer a new potential to monitor the dynamics of the tear film layers in vivo without the drawbacks of previously used methodologies. Indium phosphide–gallium qdots were used to differentially assess the dynamics of the lipid and aqueous layers of the tear film in real time. In the aqueous, qdots dispersed to form a stable local region that was swept away into the upper and lower menisci during a blink. They did not redisperse onto the ocular surface but were progressively removed from the menisci through the puncta. Some of these qdots adhered to the mucin layer on the ocular surface in a meshlike pattern and remained there for five to six blinks before they were removed. The organic qdots dispersed quickly but patchily over the whole outer surface of the tear film. They also strongly marked both eyelid margins and slowly dispersed onto the skin and eyelashes and not through the puncta. Some were trapped in the menisci as blobs that rolled along the meniscus. These data support the view of a distinct three-layered tear film: an inner mucin layer attached to the epithelial cells, a fluid aqueous layer, and an outer viscoelastic lipid layer. From the Clinical Editor Indium galium posphide quantum qdots were used to differentially assess the tear film in real time. These data support the view of a distinct three layered tear film: an inner mucin layer attached to the epithelial cells; a fluid aqueous layer; and an outer viscoelastic lipid layer.

Phosphate ester hydrolysis of biologically relevant molecules by cerium oxide nanoparticles

In an effort to characterize the interaction of cerium oxide nanoparticles (CNPs) in biological systems, we explored the reactivity of CNPs with the phosphate ester bonds of p-nitrophenylphosphate (pNPP), ATP, o-phospho- l-tyrosine, and DNA. The activity of the bond cleavage for pNPP at pH 7 is calculated to be 0.860 ± 0.010 nmol p-nitrophenol/min/μg CNPs. Interestingly, when CNPs bind to plasmid DNA, no cleavage products are detected. While cerium(IV) complexes generally exhibit the ability to break phosphorus-oxygen bonds, the reactions we report appear to be dependent on the availability of cerium(III) sites, not cerium(IV) sites. We investigated the dephosphorylation mechanism from the first principles and find the reaction proceeds through inversion of the phosphate group similar to an S N2 mechanism. The ability of CNPs to interact with phosphate ester bonds of biologically relevant molecules has important implications for their use as potential therapeutics. From the Clinical Editor The ability of cerium oxide nanoparticles to interact with phosphate ester bonds of biologically relevant molecules has important implications for their use as potential therapeutics. This team of investigators explored the reactivity of these nanoparticles with the phosphate ester bonds of p-nitrophenylphosphate, ATP, o-phospho-L-tyrosine, and DNA.

Reduced dose-limiting toxicity of intraperitoneal mitoxantrone chemotherapy using cardiolipin-based anionic liposomes

Intraperitoneal chemotherapy confers limited clinical benefit as a result of the dose-limiting toxicity of anticancer drugs. We aimed to develop optimized liposomes for mitoxantrone (MTO) administration that provide high encapsulation efficiency and increase the therapeutic index. Cationic MTO was loaded onto anionic liposomes by electrostatic surface complexation. The anticancer activity was evaluated in a peritoneal carcinomatosis model. The retention of MTO at the tumor site was monitored by molecular imaging. MTO loading efficiencies by electrostatic complexation were >95% for all anionic liposomes but <5% for neutral liposomes. Among anionic liposomes, cardiolipin liposomes (CLs) exhibited the strongest binding affinity for MTO, the highest anticancer activity, and the lowest toxicity. MTO delivered by CLs showed prolonged retention at tumor sites. Unlike free MTO showing significant cardiotoxicity, MTO administered in CLs provided negligible cardiotoxicity. CL-mediated delivery may increase the therapeutic index of MTO chemotherapy by prolonged retention and reduced cardiotoxicity. From the Clinical Editor The authors report the development of optimized liposomes for intraperitoneal mitoxantrone delivery that provides high encapsulation efficiency and increases the therapeutic index. Cardiolipin liposomes exhibited the strongest binding affinity for mitoxantrone, along with the highest anti-cancer activity and lowest toxicity, including negligible cardiotoxicity.

Effect of cholesterol and amyloid-β peptide on structure and function of mixed-lipid films and pulmonary surfactant BLES: an atomic force microscopy study

Pulmonary surfactant forms a thin molecular film inside mammalian lung alveoli and lowers the surface tension of the air/fluid interface to reduce the work of breathing. Upon compression functional surfactant forms characteristic multilayer structures, which indicate surfactant surface activity. We showed that cholesterol adversely affects both structural and surface-active properties of BLES surfactant and DPPC/DOPG lipid films. Incorporation of small concentrations of fibril-forming peptide amyloid-β 1-40 helps to counteract the distractive effect of cholesterol by improving characteristic multilayer formation that occurs upon compression. In contrast to many negative effects of amyloid-forming peptides reported earlier, we report a positive effect of amyloid-β peptide on surfactant function, which may aid in the designing of novel surfactant formulations. From the Clinical Editor The authors demonstrate the adverse effects of cholesterol from the standpoint of the structural and surface active properties of lipid films and surfactants. Incorporation of small concentrations of fibril forming peptide amyloid-ß 1-40 helps to counteract the effects of cholesterol, in contrast to many negative effects of amyloid forming peptides reported earlier.

Study of the stabilization of zinc phthalocyanine in sol-gel TiO 2 for photodynamic therapy applications

Photodynamic therapy (PDT) has emerged as an alternative and promising noninvasive treatment for cancer. It is a two-step procedure that uses a combination of molecular oxygen, visible light, and photosensitizer (PS) agents; phthalocyanine (Pc) was supported over titanium oxide but has not yet been used for cell inactivation. Zinc phthalocyanine (ZnPc) molecules were incorporated into the porous network of titanium dioxide (TiO 2) using the sol-gel method. It was prepared from stock solutions of ZnPc and TiO 2. ZnPc-TiO 2 was tested with four cancer cell lines. The characterization of supported ZnPc showed that phthalocyanine is linked by the N-pyrrole to the support and is stable up to 250°C, leading to testing for PDT. The preferential localization in target organelles such as mitochondria or lysosomes could determine the cell death mechanism after PDT. The results suggest that nanoparticulated TiO 2 sensitized with ZnPc is an excellent candidate as sensitizer in PDT against cancer and infectious diseases. From the Clinical Editor Photodynamic therapy is a two-step procedure that uses a combination of molecular oxygen, visible light and photosensitizer agents as an alternative and promising non-invasive treatment for cancer. The results of this study suggest that nanoparticulated TiO 2 sensitized with ZnPc is an excellent photosensitizer candidate against cancer and infectious diseases.

Caspase-9-dependent decrease of nuclear pore channel hydrophobicity is accompanied by nuclear envelope leakiness

Advances in nanomedicine require conceptual understanding of physiological processes. Apoptosis is a fundamental physiological process that is characterized, among other things, by an increased permeability of the nuclear envelope (NE). The latter is a tight transport barrier, known to restrict nuclear delivery rate of therapeutic nanoparticles. Therefore, an understanding of the underlying mechanism that leads to the breakdown of the barrier during apoptosis could stimulate the development of new approaches in gene therapy. We set out to elucidate this mechanism following induction of apoptosis on isolated cell nuclei. We tested the hypothesis whether caspases, mediators of apoptosis, trigger the NE leakiness at the level of the nuclear pore complexes (NPCs) using fluorescence techniques. As the permeability barrier inside the NPC channel is thought to be based on hydrophobic–hydrophobic protein interactions we further investigated the NPC channel hydrophobicity using atomic force microscopy. Caspase-9 was found to induce NE leakiness to large macromolecules. Leakiness was prevented by pretreatment of NPCs with an importin-β mutant, which irreversibly binds and thereby obstructs the NPC channel. Utilizing an ultra-sharp, hydrophobic atomic force microscope tip as a chemical nanosensor that reaches deep into the apoptotic NPC channel, a remarkable decrease of hydrophobic binding sites was detected therein. We conclude that caspase 9 gives rise to NE leakiness by perturbing the hydrophobicity-based barrier inside the NPC channel. This explains the high passive NE permeability in early apoptosis. From the Clinical Editor In this study, biological processes taking place in the nucleus during the course of apoptosis have been monitored using atomic force microscopy-based nanosensors. The conclusion was that one of the caspases, caspase 9 perturbes the hydrophobicity-based barrier inside the nuclear pore complex channel causing nuclear envelope leakiness.

Nanostructured surfaces for enhanced protein detection toward clinical diagnostics

“Label-free” biomolecule sensors for detection of inflammatory cardiovascular biomarker associated with vulnerable coronary vascular plaque rupture were designed and fabricated using micro- and nanotextured polystyrene (PS) polymer structures that functioned as sensing elements coupled with electronic measurement equipment. We demonstrated that scaling down the surface texturing from the micro- to the nanoscale enhances the amplitude of the measured detected signal strength. We believe that the nanoscale fiber morphology provides size-matched spaces for trapping and immobilizing the protein biomolecule, resulting in improved detection signal strength. We selected PS as the model system and demonstrated the detection of human serum C-reactive protein. We employed these findings in designing a platform “lab-on-a-chip” protein sensor. Comparative studies were performed on PS textured surfaces of two different surface features: a PS microsphere mat and an electrospun PS nanofiber matrix. From the Clinical Editor In this study, nanotechnology-based biosensors for vulnerable coronary vascular plaque rupture were designed and fabricated using micro- and nanotextured polystyrene polymer structures. The authors demonstrated that scaling down the surface texturing from the micro- to the nanoscale enhances the sensitivity of this detection method.

Delivery of a peptide via poly( d, l-lactic- co-glycolic) acid nanoparticles enhances its dendritic cell–stimulatory capacity

Nanoparticles (NPs) are attractive carriers for vaccines. We have previously shown that a short peptide (Hp91) activates dendritic cells (DCs), which are critical for initiation of immune responses. In an effort to develop Hp91 as a vaccine adjuvant with NP carriers, we evaluated its activity when encapsulated in or conjugated to the surface of poly( d, l-lactic- co-glycolic) acid (PLGA) NPs. We found that Hp91, when encapsulated in or conjugated to the surface of PLGA-NPs, not only activates both human and mouse DCs, but is in fact more potent than free Hp91. Hp91 packaged within NPs was about fivefold more potent than the free peptide, and Hp91 conjugated to the surface of NPs was ∼20-fold more potent than free Hp91. Because of their capacity to activate DCs, such NP-Hp91 systems are promising as delivery vehicles for subunit vaccines against infectious disease or cancer. From the Clinical Editor In this paper, nanoparticle-based dendritic cell activating vaccines are described and discussed. The authors report that the presented PLGA NP based vaccine constructs increase the potency of the studied vaccine by up to 20-fold, making them promising as delivery vehicles for subunit vaccines against infectious diseases or cancer.