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MgAl2O4 spinel mesh with micro-features of 410 and 250 μm unit cell length and rib thickness, respectively, was three-dimensional (3D) printed and sintered followed by Hot Isostatic Pressing (HIPin...

Diseases affecting the retina, such as age-related macular degeneration (AMD), diabetic retinopathy, macular edema, and retinal vein occlusions, are currently treated by the intravitreal injection of drug formulations. These disease pathologies are driven by oxidative damage due to chronic high concentrations of reactive oxygen species (ROS) in the retina. Intravitreal injections often induce retinal detachment, intraocular hemorrhage, and endophthalmitis. Furthermore, the severe eye pain associated with these injections lead to patient noncompliance and treatment discontinuation. Hence, there is a critical need for the development of a noninvasive therapy that is effective for a prolonged period for treating retinal diseases. In this study, we developed a noninvasive cerium oxide nanoparticle (CNP) delivery wafer (Cerawafer) for the modulation of ROS in the retina. We fabricated Cerawafer loaded with CNP and determined its SOD-like enzyme-mimetic activity and ability to neutralize ROS generated in vitro. We demonstrated Cerawafer's ability to deliver CNP in a noninvasive fashion to the retina in healthy mouse eyes and the CNP retention in the retina for more than a week. Our studies have demonstrated the in vivo efficacy of the Cerawafer to modulate ROS and associated down-regulation of VEGF expression in the retinas of very-low-density lipoprotein receptor knockout (vldlr-/-) mouse model. The development of a Cerawafer nanotherapeutic will fulfill a hitherto unmet need. Currently, there is no such therapeutic available, and the development of a Cerawafer nanotherapeutic will be a major advancement in the treatment of retinal diseases.

Background The mechanism by which immune cells regulate metastasis is unclear. Understanding the role of immune cells in metastasis will guide the development of treatments improving patient survival. Methods We used syngeneic orthotopic mouse tumour models (wild-type, NOD/scid and Nude), employed knockout (CD8 and CD4) models and administered CXCL4. Tumours and lungs were analysed for cancer cells by bioluminescence, and circulating tumour cells were isolated from blood. Immunohistochemistry on the mouse tumours was performed to confirm cell type, and on a tissue microarray with 180 TNBCs for human relevance. TCGA data from over 10,000 patients were analysed as well. Results We reveal that intratumoral immune infiltration differs between metastatic and non-metastatic tumours. The non-metastatic tumours harbour high levels of CD8+ T cells and low levels of platelets, which is reverse in metastatic tumours. During tumour progression, platelets and CXCL4 induce differentiation of monocytes into myeloid-derived suppressor cells (MDSCs), which inhibit CD8+ T-cell function. TCGA pan-cancer data confirmed that CD8lowPlatelethigh patients have a significantly lower survival probability compared to CD8highPlateletlow. Conclusions CD8+ T cells inhibit metastasis. When the balance between CD8+ T cells and platelets is disrupted, platelets produce CXCL4, which induces MDSCs thereby inhibiting the CD8+ T-cell function.

Eye injuries due to corneal abrasions, chemical spills, penetrating wounds, and microbial infections cause corneal scarring and opacification that result in impaired vision or blindness. However, presently available eye drop formulations of anti-inflammatory and antibiotic drugs are not effective due to their rapid clearance from the ocular surface or due to drug-related side effects such as cataract formation or increased intraocular pressure. In this article, we presented the development of a dextran sulfate-based polymer wafer (DS-wafer) for the effective modulation of inflammation and fibrosis and demonstrated its efficacy in two corneal injury models: corneal abrasion mouse model and alkali induced ocular burn mouse model. The DS-wafers were fabricated by the electrospinning method. We assessed the efficacy of the DS-wafer by light microscopy, qPCR, confocal fluorescence imaging, and histopathological analysis. These studies demonstrated that the DS-wafer treatment is significantly effective in modulating corneal inflammation and fibrosis and inhibited corneal scarring and opacification compared to the unsulfated dextran-wafer treated and untreated corneas. Furthermore, these studies have demonstrated the efficacy of dextran sulfate as an anti-inflammatory and antifibrotic polymer therapeutic.

Gene and drug delivery to the retina is a critical therapeutic goal. While the majority of inherited forms of retinal degeneration affect the outer retina, specifically the photoreceptors and retinal pigment epithelium, effective targeted delivery to this region requires invasive subretinal delivery. Our goal in this work was to evaluate two innovative approaches for increasing both the persistence of delivered nanospheres and their penetration into the outer retina while using the much less invasive intravitreal delivery method. We formulated novel hyaluronic acid nanospheres (HA-NS, 250 nm and 500 nm in diameter) conjugated to fluorescent reporters and delivered them intravitreally to the adult Balb/C mouse retina. They exhibited persistence in the vitreous and along the inner limiting membrane (ILM) for up to 30 days (longest timepoint examined) but little retinal penetration. We thus evaluated the ability of the small molecule, sulfotyrosine, to disrupt the ILM, and found that 3.2 µg/µL sulfotyrosine led to significant improvement in delivery to the outer retina following intravitreal injections without causing retinal inflammation, degeneration, or loss of function. Co-delivery of sulfotyrosine and HA-NS led to robust improvements in penetration of HA-NS into the retina and accumulation along the interface between the photoreceptors and the retinal pigment epithelium. These exciting findings suggest that sulfotyrosine and HA-NS may be an effective strategy for outer retinal targeting after intravitreal injection.

Nitric oxide (NO) is a highly reactive gas molecule, exhibiting antimicrobial properties. Because of its reactive nature, it is challenging to store and deliver NO efficiently as a therapeutic agent. The objective of this study was to develop NO-releasing polymeric fibers (NO-fibers), as an effective delivery platform for NO. NO-fibers were fabricated with biopolymer solutions of polyvinyl pyrrolidone (PVP) and ethylcellulose (EC), and derivatives of N-diazeniumdiolate (NONOate) as NO donor molecules, using an electrospinning system. We evaluated in vitro NO release kinetics, along with antimicrobial effects and cytotoxicity in microorganisms and human cell culture models. We also studied the long-term stability of NONOates in NO-fibers over 12 months. We demonstrated that the NO-fibers could release NO over 24 h, and showed inhibition of the growth of Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA), without causing cytotoxicity in human cells. NO-fibers were able to store NONOates for over 12 months at room temperature. This study presents the development of NO-fibers, and the feasibility of NO-fibers to efficiently store and deliver NO, which can be further developed as a bandage.

Drug delivery to the posterior segment of the eye remains challenging even though the eye is readily accessible. Its unique and complex anatomy and physiology contribute to the limited options for drug delivery via non-invasive topical treatment, which is the prevalent ophthalmic treatment. To treat the most common retinal diseases, intravitreal (IVT) injection has been a common and effective therapy. With the advancement of nanotechnologies, novel formulations and drug delivery systems are being developed to treat posterior segment diseases. Here, we discuss the recent advancement in ocular delivery systems, including-sustained release formulations, IVT implants, and preclinical topical formulations, and the challenges faced in their clinical translation.

Development of inflammation modulating polymer scaffolds for soft tissue repair with minimal postsurgical complications is a compelling clinical need. However, the current standard of care soft tissue repair meshes for hernia repair is highly inflammatory and initiates a dysregulated inflammatory process causing visceral adhesions and postsurgical complications. Herein, the development of an inflammation modulating biomaterial scaffold (bioscaffold) for soft tissue repair is presented. The bioscaffold design is based on the idea that, if the excess proinflammatory cytokines are sequestered from the site of injury by the surgical implantation of a bioscaffold, the inflammatory response can be modulated, and the visceral adhesion formations and postsurgical complications can be minimized. The bioscaffold is fabricated by 3D-bioprinting of an in situ phosphate crosslinked poly(vinyl alcohol) polymer. In vivo efficacy of the bioscaffold is evaluated in a rat ventral hernia model. In vivo proinflammatory cytokine expression analysis and histopathological analysis of the tissues have confirmed that the bioscaffold acts as an inflammation trap and captures the proinflammatory cytokines secreted at the implant site and effectively modulates the local inflammation without the need for exogenous anti-inflammatory agents. The bioscaffold is very effective in inhibiting visceral adhesions formation and minimizing postsurgical complications.

A synergy between the polymer biomaterial and drug plays an important role in enhancing the therapeutic efficacy, improving the drug stability, and minimizing the local immune responses in the development of drug delivery systems. Particularly, in the case of ocular drug delivery, the need for the development of synergistic drug delivery system becomes more pronounced because of the wet ocular mucosal surface and highly innervated cornea, which elicit a strong inflammatory response to the instilled drug formulations. This article presents the development of a synergistic cysteamine delivery nanowafer to treat corneal cystinosis. Corneal cystinosis is a rare metabolic disease that causes the accumulation of cystine crystals in the cornea resulting in corneal opacity and loss of vision. It is treated with topical cysteamine (Cys) eye drops that need to be instilled 6-12 times a day throughout the patient's life, which causes side effects such as eye pain, redness, and ocular inflammation. As a result, compliance and treatment outcomes are severely compromised. To surmount these issues, we have developed a clinically translatable Cys nanowafer (Cys-NW) that can be simply applied on the eye with a fingertip. During the course of the drug release, Cys-NW slowly dissolves and fades away. The in vivo studies in cystinosin knockout mice demonstrated twice the therapeutic efficacy of Cys-NW containing 10 μg of Cys administered once a day, compared to 44 μg of Cys as topical eye drops administered twice a day. Furthermore, Cys-NW stabilizes Cys for up to four months at room temperature compared to topical Cys eye drops that need to be frozen or refrigerated and still remain active for only 1 week. The Cys-NW, because of its enhanced therapeutic efficacy, safety profile, and extended drug stability at room temperature, can be rapidly translated to the clinic for human trials.

Autologous cell transplantation holds enormous promise to restore organ and tissue functions in the treatment of various pathologies including endocrine, cardiovascular, and neurological diseases among others. Even though immune rejection is circumvented with autologous transplantation, clinical adoption remains limited due to poor cell retention and survival. Cell transplant success requires homing to vascularized environment, cell engraftment and importantly, maintenance of inherent cell function. To address this need, we developed a three dimensional (3D) printed cell encapsulation device created with polylactic acid (PLA), termed neovascularized implantable cell homing and encapsulation (NICHE). In this paper, we present the development and systematic evaluation of the NICHE in vitro, and the in vivo validation with encapsulated testosterone-secreting Leydig cells in Rag1-/- castrated mice. Enhanced subcutaneous vascularization of NICHE via platelet-rich plasma (PRP) hydrogel coating and filling was demonstrated in vivo via a chorioallantoic membrane (CAM) assay as well as in mice. After establishment of a pre-vascularized bed within the NICHE, transcutaneously transplanted Leydig cells, maintained viability and robust testosterone secretion for the duration of the study. Immunohistochemical analysis revealed extensive Leydig cell colonization in the NICHE. Furthermore, transplanted cells achieved physiologic testosterone levels in castrated mice. The promising results provide a proof of concept for the NICHE as a viable platform technology for autologous cell transplantation for the treatment of a variety of diseases.

Dry eye disease is a major public health problem that affects millions of people worldwide. It is presently treated with artificial tear and anti-inflammatory eye drops that are generally administered several times a day and may have limited therapeutic efficacy. To improve convenience and efficacy, a dexamethasone (Dex) loaded nanowafer (Dex-NW) has been developed that can release the drug on the ocular surface for a longer duration of time than drops, during which it slowly dissolves. The Dex-NW was fabricated using carboxymethyl cellulose polymer and contains arrays of 500 nm square drug reservoirs filled with Dex. The in vivo efficacy of the Dex-NW was evaluated using an experimental mouse dry eye model. These studies demonstrated that once a day Dex-NW treatment on alternate days during a five-day treatment period was able to restore a healthy ocular surface and corneal barrier function with comparable efficacy to twice a day topically applied dexamethasone eye drop treatment. The Dex-NW was also very effective in down regulating expression of inflammatory cytokines (TNF-α, and IFN-γ), chemokines (CXCL-10 and CCL-5), and MMP-3, that are stimulated by dry eye. Despite less frequent dosing, the Dex-NW has comparable therapeutic efficacy to topically applied Dex eye drops in experimental mouse dry eye model, and these results provide a strong rationale for translation to human clinical trials for dry eye.

The hydrogel template strategy was previously developed to fabricate homogeneous polymeric microparticles. Here, we demonstrate the versatility of the hydrogel template strategy for the development of nanowafer-based ocular drug delivery systems. We describe the fabrication of dexamethasone-loaded nanowafers using polyvinyl alcohol and the instillation of a nanowafer on a mouse eye. The nanowafer, a small circular disk, is placed on the ocular surface, and it releases a drug as it slowly dissolves over time, thus increasing ocular bioavailability and enhancing efficiency to treat eye injuries.

The hydrogel template strategy was previously developed to fabricate homogeneous polymeric microparticles. Here, we demonstrate the versatility of the hydrogel template strategy for the development of nanowafer-based ocular drug delivery systems. We describe the fabrication of dexamethasone-loaded nanowafers using polyvinyl alcohol and the instillation of a nanowafer on a mouse eye. The nanowafer, a small circular disk, is placed on the ocular surface, and it releases a drug as it slowly dissolves over time, thus increasing ocular bioavailability and enhancing efficiency to treat eye injuries.

Metastatic breast cancer is the most dreadful malignant disease that accounts for the majority of cancer-related deaths worldwide among women. A number of studies have shown that the tumor microenvironment (TME) plays a crucial role in regulating metastasis. It is therefore imperative to understand the dynamic interactions between cancer cells and their microenvironment to examine the molecular interaction and to effectively target cancer cells. TME comprises a variety of cells including immune cells which can influence tumor survival, growth and metastasis. Tumor-infiltrating lymphocytes (TILs), in particular, the CD8 T lymphocytes, has emerged as a promising prognostic marker for immunotherapy in a variety of cancers. However, the key molecular factors that regulate the cross-talk between tumor cells and CD8 T lymphocytes and its impact on metastatic traits in breast cancer is still inconclusive. Platelets are crucial components of the tumor microenvironment that are known to modulate tumor promotion and metastasis. The contribution of platelets and platelet secreted molecules are also carefully examined in metastasis of various cancers. The primary objective of this study is to investigate the role of CD8 T lymphocytes and platelets in breast tumor progression using isogenic tumor lines that form identical primary tumors but differ in their ability to develop metastasis. Citation Format: Robiya Joseph, Rama Soundararajan, Suhas Vasaikar, Fei Yang, Sevinj Isgandarova, Lin Tian, Monika Haemmerle, Barbara Mino, Tieling Zhou, Geraldine Vidhya Raja, Esmeralda Ramirez Pena, Petra Den Hollander, Neeraja Bhangre, Crystal Shin, Melisa Martinez, Jaime Rodriguez Canales, Jeffrey Chang, Anil Sood, Ignacio Ivan Wistuba, Don L. Gibbons, Jeffrey M. Rosen, Ghanashyam Acharya, Navin Varadarajan, Xiang H. Zhang, Sendurai A. Mani. Regulation of metastasis by CD8 T lymphocytes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3761.

Purpose To evaluate the efficacy of a controlled release dexamethasone delivery system for suppressing inflammation in an ocular burn + desiccating stress (OB+DS) model. Methods Nanowafers (NW) loaded with Dexamethasone (Dex, 10 μg) or vehicles (2.5% Methylcellulose; MC) were fabricated using hydrogel template strategy. C57BL/6 mice were subjected to unilateral alkali ocular burn with concomitant desiccating stress for 2 or 5 days and topically treated either with 2 μL of 0.1% Dex or vehicle four times per day and compared with mice that had MC-NW or Dex-NW placed on their corneas. Clinical parameters were evaluated daily. Mice were euthanized after 2 or 5 days. Quantitative PCR evaluated the expression of inflammatory cytokines IL-1β and IL-6 and matrix metalloproteinases (MMP) in whole cornea lysates. Myeloperoxidase activity (MPO) was measured using a commercial kit in cornea lysates. Results Both Dex drop and Dex-NW groups had significantly lower corneal opacity scores compared with their vehicles. Both Dex drops and Dex-NW significantly decreased expression of IL-1β, IL-6, and MMP-9 RNA transcripts compared with vehicle drops or wafers 2 and 5 days after the initial lesion. A significant lower number of neutrophils was found in both Dex treatment groups and this was accompanied by decreased MPO activity compared with vehicle controls. Conclusions Dex-NW has efficacy equal to Dex drops in preserving corneal clarity and decreasing expression of MMPs and inflammatory cytokines of the corneas of mice subjected to an OB+DS model.

Surgical wound healing applications require bioprosthetics that promote cellular infiltration and vessel formation, metrics associated with increased mechanical strength and resistance to infection. Porcine acellular lung matrix is a novel tissue scaffold known to promote cell adherence while minimizing inflammatory reactions. In this study, we evaluate the capacity of porcine acellular lung matrix to sustain cellularization and neovascularization in a rat model of subcutaneous implantation and chronic hernia repair. We hypothesize that, compared to human acellular dermal matrix, porcine acellular lung matrix would promote greater cell infiltration and vessel formation. Following pneumonectomy, porcine lungs were processed and characterized histologically and by scanning electron microscopy to demonstrate efficacy of the decellularization. Using a rat model of subcutaneou implantation, porcine acellular lung matrices (n = 8) and human acellular dermal matrices (n = 8) were incubated in vivo for 6 weeks. To evaluate performance under mechanically stressed conditions, porcine acellular lung matrices (n = 7) and human acellular dermal matrices (n = 7) were implanted in a rat model of chronic ventral incisional hernia repair for 6 weeks. After 6 weeks, tissues were evaluated using hematoxylin and eosin and Masson’s trichrome staining to quantify cell infiltration and vessel formation. Porcine acellular lung matrices were shown to be successfully decellularized. Following subcutaneous implantation, macroscopic vessel formation was evident. Porcine acellular lung matrices demonstrated sufficient incorporation and showed no evidence of mechanical failure after ventral hernia repair. Porcine acellular lung matrices demonstrated significantly greater cellular density and vessel formation when compared to human acellular dermal matrix. Vessel sizes were similar across all groups. Cell infiltration and vessel formation are well-characterized metrics of incorporation associated with improved surgical outcomes. Porcine acellular lung matrices are a novel class of acellular tissue scaffold. The increased cell and vessel density may promote long-term improved incorporation and mechanical properties. These findings may be due to the native lung scaffold architecture guiding cell migration and vessel formation. Porcine acellular lung matrices represent a new alternative for surgical wound healing applications where increased cell density and vessel formation are sought.

The hydrogel template method was used to fabricate homogeneous drug-PLGA microparticles. Four drugs (felodipine, risperidone, progesterone, and paclitaxel) were loaded into the PLGA particles with the homogeneous size of 10microm, 20microm, and 50microm. The drug loading into the PLGA microparticles was 50% and higher. The felodipine-PLGA microstructures of four different sizes showed that the drug release kinetics is dependent on the total surface area available for drug release. The smaller the particle size, the release rate was faster. Two types of microparticles (10microm diameter and 10microm height, and 50microm diameter and 5microm height) showed zero-order release and complete release was observed within 2weeks. The release rate, however, was not exactly proportional to the surface area. Different drugs which were loaded into the same PLGA formulation showed different release profiles. The main difference was on the initial burst release. The overall release profile seems to be similar for different drugs, if the release profile is adjusted to eliminate the burst release. The initial burst release appears to be inversely related to the water-solubility of a drug, i.e., the lower the water-solubility of a drug, the higher the burst release. The hydrogel template method allowed preparation of homogeneous particles with predefined sizes with high drug loading. It allowed study on the effect of size and shape on the drug release kinetics. With the microparticles of homogeneous size and shape, the drug release kinetics can be projected based on the size of microparticles and water-solubility of a drug. The ability of making homogeneous particles is expected to provide better prediction and reproducibility of the drug release property of a given formulation.

Nano/microparticles have been used widely in drug delivery applications. The majority of the particles are prepared by the conventional emulsion methods, which tend to result in particles with heterogeneous size distribution with sub-optimal drug loading and release properties. Recently, microfabrication methods have been used to make nano/microparticles with a monodisperse size distribution. The existing methods utilize solid templates for making particles, and the collection of individual particles after preparation has not been easy. The new hydrogel template approach was developed to make the particle preparation process simple and fast. The hydrogel template approach is based on the unique properties of physical gels that can undergo sol-gel phase transition upon changes in environmental conditions. The phase reversible hydrogels, however, are in general mechanically too weak to be treated as a solid material. It was unexpectedly found that gelatin hydrogels could be made to possess various properties necessary for microfabrication of nano/microparticles in large quantities. The size of the particles can be adjusted from 200 nm to >50 microm, providing flexibility in controlling the size in drug delivery formulations. The simplicity in processing makes the hydrogel template method useful for scale-up manufacturing of particles. The drug loading capacity is 50% or higher, and yet the initial burst release is minimal. The hydrogel template approach presents a new strategy of preparing nano/microparticles of predefined size and shape with homogeneous size distribution for drug delivery applications.

We describe an integrated approach for detection of diagnostic markers using in situ assembled optical diffraction gratings in combination with immunomagnetic capture. Folate receptor (FR), a serum protein indicative of various cancers, was chosen as a model system to demonstrate the potential of the method. Magnetic beads coupled to FR antibody were used to capture FR from serum. The FR-bound magnetic beads self-assembled onto microcontact-printed folate-coupled BSA (F-BSA) patterns to form diffraction gratings which served to detect FR by measuring the diffraction intensities caused by laser illumination. The FR-containing beads, upon binding to the F-BSA surface, served as intrinsic signal enhancement agents, circumventing the need for additional enzymatic signal amplification or fluorescent labeling steps. With this approach, a detection sensitivity of 700 fM (20 pg/mL) was achieved. The potential use of this approach in clinical diagnostics was demonstrated by measuring FR concentration in blood samples obtained from cancer patients.

Presently, eye injuries are treated by topical eye drop therapy. Because of the ocular surface barriers, topical eye drops must be applied several times in a day, causing side effects such as glaucoma, cataract, and poor patient compliance. This article presents the development of a nanowafer drug delivery system in which the polymer and the drug work synergistically to elicit an enhanced therapeutic efficacy with negligible adverse immune responses. The nanowafer is a small transparent circular disc that contains arrays of drug-loaded nanoreservoirs. The slow drug release from the nanowafer increases the drug residence time on the ocular surface and its subsequent absorption into the surrounding ocular tissue. At the end of the stipulated period of drug release, the nanowafer will dissolve and fade away. The in vivo efficacy of the axitinib-loaded nanowafer was demonstrated in treating corneal neovascularization (CNV) in a murine ocular burn model. The laser scanning confocal imaging and RT-PCR study revealed that once a day administered axitinib nanowafer was therapeutically twice as effective, compared to axitinib delivered twice a day by topical eye drop therapy. The axitinib nanowafer is nontoxic and did not affect the wound healing and epithelial recovery of the ocular burn induced corneas. These results confirmed that drug release from the axitinib nanowafer is more effective in inhibiting CNV compared to the topical eye drop treatment even at a lower dosing frequency.

The clinical importance of drug-eluting stents (DESs) has been demonstrated by their unparalleled success in preventing restenosis after stenting procedures. The magnitude of success is historic despite their short history. The current DESs deliver a single drug aiming to prevent or minimize proliferation of smooth muscle cells. Since the restenosis process involves several different biological responses, the ability to deliver the right drugs at the right times is critical for further development of the second generation of DESs. As the type of drugs that can be delivered from DESs varies, it is imperative to understand the drug delivery mechanisms and the approaches available for drug coating on the stents. The drug delivery mechanisms of current DESs that have been used clinically and under clinical trials are explained.

Our previous studies on low molecular weight hydrotropes showed that nicotinamide derivatives increased the aqueous solubility of paclitaxel by several orders of magnitude. We were interested in knowing whether the polymeric forms of those low molecular weight hydrotropes could maintain hydrotropic properties. N-Picolylnicotinamide (PNA) was one of the best hydrotropes identified for paclitaxel, and polymers based on PNA were synthesized and tested for their hydrotropic properties. The pendent hydrotropic PNA moieties were attached to the polymer backbone through either an oligo(ethylene glycol) or a phenyl group as a spacer. The PNA moiety was bound to the polymer backbone either at the 2-position or at the 6-position of the pyridine ring of nicotinamide to result in poly(2-(4-vinylbenzyloxy)-N-picolylnicotinamide) (P(2-VBOPNA)) or poly(6-(4-vinylbenzyloxy)-N-picolylnicotinamide) (P(6-VBOPNA)), respectively. The ability of PNA-containing polymers to increase the aqueous solubility of paclitaxel was exami...

A new methodology for conversion of inert surfaces to biocompatible surfaces was proposed. A gold plate, a quartz plate, a silicon wafer, and a Teflon sheet were selected as substrates. The surfaces of the first three substrates were hydroxylated by chemical methods, and the Teflon surface was activated by oxygen plasma treatment. A titania layer was adsorbed on these substrates to provide active surfaces for adsorption of biomolecules. The adsorption process of four representative biomolecules (collagen, fibrinogen, insulin, and heparin) was monitored by quartz crystal microbalance and IR and X-ray photoelectron spectroscopies. The adsorbed proteins were stably bound up to 60 °C and at a wide pH range. The biological activity of adsorbed fibrinogen was confirmed by treatment with thrombin to produce a fibrin network on the surface, as evidenced by scanning electron microscopy.

Purpose. To identify hydrotropic agents that can increase aqueous paclitaxel (PTX) solubility and to study the chemical structures necessary for hydrotropic properties so that polymeric hydrotropic agents can be synthesized.

Altogether eight sugar-based amphiphiles were synthesized. Out of these, four amphiphiles contained only one hydrocarbon chain in their hydrophobic segment. Two of these single-chain amphiphiles contained fully cyclic, disaccharide headgroups, while the other two were made of one cyclic sugar unit connected to the hydrocarbon chain via open, reduced alditol units. The first two single-chain amphiphiles formed vesicles upon suspension in water as indicated by transmission electron microscopy and dye entrapment experiments.Thediameters of these vesicles ranged from 500 to $800 \AA$. Uponaging, these vesicles transformed into tubular and lamellar microstructures. However, the other two single-chain amphiphiles produced micelles in water. Four double-chain systems including two glycolipid analogues, N-hexadecyl-(1- hexadecylamido)-\beta-D-lactoside andN-hexadecyl-(1-hexadecylamido)- \beta -D-maltoside, were also synthesized. The other two double-chain (dihexadecyl ether) lipids were based on a pseudoglyceryl backbone where the headgroup residues weremadeof amino-\beta -D-maltoside and amino-\beta -D-lactoside, respectively. All the doublechain amphiphiles formed vesiclesuponsuspension in water as indicated by transmission electron microscopy and dye entrapment experiments. The diameters of these vesicles ranged from $\sim 1000$ to $1100 \AA$. X-ray diffraction of the cast films of the vesicle-forming amphiphiles indicated a lamellar thickness of $\sim 58-60 \AA$ for these membranous organizations. The vesicular aggregates showed sharp, solid-to-fluid thermal transitions that ranged from $\sim 52$ to $62^oC$. Formation of giant-sized vesicles from the single-chain amphiphiles could also be triggered by complex formation with $Cu^{2+}$ ions under ambient pH conditions.

Six disaccharide amphiphiles were synthesized and their hydrogel-forming behavior was extensively studied. These amphiphiles were based on maltose and lactose. Since the gels formed from some of these systems showed the ability to "trap" water molecules upon gelation, these gels were described as "hydrogels". When these gels were heated to similar to 70 degrees C, the samples turned into clear, isotropic fluids, and upon gradual cooling, the hydrogels could be reproduced. Thus these systems were also "thermoreversible". The low molecular mass (MW 565) of the gelators compared to that of a typical polymeric gelator forming substance implies pronounced aggregation of the disaccharide amphiphiles into larger microstructures during gelation. To discern the aggregate textures and morphologies, the specimen hydrogel samples were examined by high-resolution scanning electron microscopy (SEM). A possible reason for the exceptionally high water gelating capacities (>6000 molecules of water per gelator molecule) exhibited by these N-alkyl disaccharide amphiphiles is the presence of large interlamellar spaces into which the water molecules get entrapped due to surface tension. In contrast to their single-chain counterparts, the double-chain lactosyl and maltosylamine amphiphiles upon solubilization in EtOH-H2O afforded hydrogels with reduced mechanical strengths. Interestingly, the corresponding microstructures were found to be quite different from the corresponding hydrogels of their single-chain counterparts. Rheological studies provided further insights into the behavior of these hydrogels. Varying the chain length of the alcohol cosolvent could modulate the gelation capacities, melting temperatures, and the mechanical properties of these hydrogels. To explain the possible reasons of gelation, the results of molecular modeling and energy minimization studies were also included.

Synthetic routes leading to 12 L-phenylalanine based mono- and bipolar derivatives (1-12) and an in-depth study of their structure-property relationship with respect to gelation have been presented. These include monopolar systems such as N-[(benzyloxy)carbonyl]-L-phenylalanine-N-alkylamides and the corresponding bipolar derivatives with flexible and rigid spacers such as with 1,12-diaminododecane and 4,4'-diaminodiphenylmethane, respectively. The two ends of the latter have been functionalized with N-[(benzyloxy)carbonyl]-L-phenylalanine units via amide connection. Another bipolar molecule was synthesized in which the middle portion of the hydrocarbon segment contained polymerizable diacetylene unit. To ascertain the role of the presence of urethane linkages in the gelator molecule protected L-phenylalanine derivatives were also synthesized in which the (benzyloxy)carbonyl group has been replaced with (tert-butyloxy)carbonyl, acetyl, and benzoyl groups, respectively. Upon completion of the synthesis and adequate characterization of the newly described molecules, we examined the aggregation and gelation properties of each of them in a number of solvents and their mixtures. Optical microscopy and electron microscopy further characterized the systems that formed gels. Few representative systems, which showed excellent gelation behavior was, further examined by FT-IR, calorimetric, and powder X-ray diffraction studies. To explain the possible reasons for gelation, the results of molecular modeling and energy-minimization studies were also included. Taken together these results demonstrate the importance of the presence of (benzyloxy)carbonyl unit, urethane and secondary amide linkages, chiral purities of the headgroup and the length of the alkyl chain of the hydrophobic segment as critical determinants toward effective gelation.

Quantitative characterization of biomolecules is critical for molecular diagnostics and drug development. Several assays based on spectrophotometry, fluorometry, chemiluminescence, and electrochemical immunoassays have been reported for biomolecular detection. These methods are often slow owing to multiple sample pretreatment steps that increase analysis time and cost. Immunoassays that combine high sensitivity with fast, robust, and inexpensive methods for biomolecular detection are of growing importance. Herein the development of a self-assembled optical diffraction biosensor is described which is devoid of microfabrication or enzymatic amplification for the rapid detection of S-adenosyl homocysteine (SAH), a potential diagnostic marker for cardiovascular disease, with a sensitivity limit of 24.5 pgmL . SAH is a low-molecular-mass analyte (384 Da) consisting of the nucleoside adenine joined to the amino acid homocysteine (Hcy) by a 5’ thioether linkage. Our method relies on a sandwich-binding approach, wherein SAH is bound by an antibody through the Hcy moiety while an adenine-specific RNA aptamer binds to the adenine moiety (Figure 1). We designed a strategy using antibody-coupled (Ab) beads to capture SAH from solution in addition to aptamerfunctionalized micropatterns specific for adenine which are stamped on a gold-coated glass slide (gold chip). Based on these specific interactions, SAH bound to the Ab beads produces a self-assembled optical diffraction grating upon exposure to the aptamer-functionalized micropatterns (Figure 2). The high-affinity adenosine-specific aptamer containing the 39-mer sequence CGG AUG AGA CGC UUG GCG UGU GCU GUG GAG AGU CAU CCG was chosen

NEWS COVERAGE: A news release based on this journal publication is available online: http://news.rice.edu/2016/11/10/rice-expands-graphene-repertoire-with-mri-contrast-agent/

Nano/microparticulate drug delivery systems with homogeneous size distribution and predefined shape are important in understanding the influence of the geometry and dimensions of these systems on blood circulation times and cellular uptake. We present a general method using water dissolvable hydrogel templates for the fabrication of homogeneous, shape-specific polymer/drug constructs in the size range of 200 nm to 50 μm. This hydrogel template strategy is mild, inexpensive, and readily scalable for the fabrication of multifunctional drug delivery vehicles.

Nano/microparticulate drug delivery systems with homogeneous size distribution and predefined shape are important in understanding the influence of the geometry and dimensions of these systems on blood circulation times and cellular uptake. We present a general method using water dissolvable hydrogel templates for the fabrication of homogeneous, shape-specific polymer/drug constructs in the size range of 200 nm to 50 μm. This hydrogel template strategy is mild, inexpensive, and readily scalable for the fabrication of multifunctional drug delivery vehicles.

It is important to screen our food supply for pathogen contaminations. Current methods to screen for bacterial contamination involve using costly reagents such as antibodies or PCR reagents or time-costly growth in cultures. There is need for portable, real-time, multiple x pathogen detection technology that can predict the safety of food where it is produced or distributed. Surface plasmon resonance (SPR) imaging is a sensitive, la bel-free method that can detect the binding of an analyte to a surface due to changes in refractive index th at occur upon binding. It can be used for label–free detection of the presence of potential pathogens. Simulta neous fluorescence molecular imaging on the other side of the biochip can be used to ascertain pathogen status or functional state which may affect its potential danger to humans or animals. We are designing and testing hybrid microfluidic biochips to detect multiple pathogens using a combination of SPRI and fluorescence imaging. The device consists of an array of gold spots, each functionalized with a peptide targeting a specific pathogen. This peptide biosensor arra y is enclosed by a PDMS microfluidic flow chamber that delivers a magnetically concentrated sample to be tested. An SPR image is taken from the bottom of the biochip. Image analysis is used to quantify the amount of pathogen (both live and dead ) bound to each spot. Since PDMS is very transmissive to visible light, an epi-fluorescence image is taken from the top of the biochip. Fluorescence imaging determines the live:dead ratio of each pathogen using an inexpensive SYTO 9®-Propidium Iodide assay. The volume of sample that the biochip can analyze is small, so possible pathogens are pre-concentrated using immunomagnetic separation. Functionaliz ed magnetic particles are bound to pathogens present in the sample, and a magnet is used to separate them from the bulk fluid. KEY TERMS: foodborne pathog ens; microfluidic; imaging; surface plasmon resonance; E. coli O157:H7

Current methods to screen for bacterial contamination involve using costly reagents such as antibodies or PCR reagents or time-costly growth in cultures. There is need for portable, real-time, multiplex pathogen detection technology that can predict the safety of food. Surface plasmon resonance (SPR) imaging is a sensitive, label-free method that can detect the binding of an analyte to a surface by the changes in refractive index that occur upon binding. We have designed a hybrid microfluidic biochip to perform multiplexed detection of single-celled pathogens using a combination of SPR and fluorescence imaging. The device consists of an array of gold spots, each functionalized with a capture biomolecule targeting a specific pathogen. This biosensor array is enclosed by a polydimethylsiloxane microfluidic flow chamber that delivers a magnetically concentrated sample to be tested. The sample is imaged by SPR on the bottom of the biochip and epi-fluorescence on the top. The prototype instrument was successfully able to image antibody-captured E. coli O157:H7 bacteria by SPR and fluorescence imaging. The efficiency of capture of these bacteria by the magnetic particles was determined using spectrophotometric ferric oxide absorbance measurements. The binding of the E. coli to each spot was quantified by measuring the percent of the gold spot area upon which the bacteria was bound and analyzed using NIH ImageJ software. This hybrid imaging approach of pathogenic E. coli detection coupled with an estimate of relative infectivity is shown to be a working example of a testing device for potential foodborne pathogens.

We report a broadly applicable optical method for rapid and label-free detection of as few as 45 cells. In this method, bacterial cells are detected by measuring the amount of laser light transmitted through a small glass well functionalized with antibodies which specifically recognize and capture the cells. The described approach is simple, rapid, economical, and promising for portable and high-throughput detection of a wide variety of pathogenic and infectious cells.

To identify hydrotropic agents that can increase aqueous paclitaxel (PTX) solubility and to study the chemical structures necessary for hydrotropic properties so that polymeric hydrotropic agents can be synthesized.More than 60 candidate hydrotropic agents (or hydrotropes) were tested for their ability to increase the aqueous PTX solubility. A number of nicotinamide analogues were synthesized based on the observation that nicotinamide showed a favorable hydrotropic property. The identified hydrotropes for PTX were used to examine the structure-activity relationship.N,N-Diethylnicotinamide (NNDENA) was found to be the most effective hydrotropic agent for PTX. The aqueous PTX solubility was 39 mg/ml and 512 mg/ml at NNDENA concentrations of 3.5 M and 5.95 M, respectively. These values are 5-6 orders of magnitude greater than the intrinsic solubility of 0.30 +/- 0.02 microg/ml. N-Picolylnicotinamide, N-allylnicotinamide, and sodium salicylate were also excellent hydrotropes for PTX. Solubility data showed that an effective hydrotropic agent should be highly water soluble while maintaining a hydrophobic segment.The present study identified several hydrotropic agents effective for increasing aqueous solubility of PTX and analyzed the structural requirements for this hydrotropic property. This information can be used to find other hydrotropic compounds and to synthesize polymeric hydrotropes that are effective for PTX and other poorly water-soluble drugs.

Single crystals of a symmetrically substituted molecule, 1,3,5-triazine-2,4,6-triaminehexaacetic acid, (TTHA) and its Ca2+ salt have been synthesized, the analysis of which reveals the existence of novel channel type cavities and helical packing organizations in the crystals.

The authors report experiments with a diffraction-based biosensor based on self-assembly of target-containing nanobeads that form optical diffraction gratings. They demonstrate that the diffraction signal is a function of the bead size, and that noise is minimized by normalizing the intensities of the diffraction modes. They characterize the dependence of the diffraction signal on equivalent bead size and demonstrate the potential of the scheme in detecting biologically significant molecules. © 2007 American Institute of Physics. DOI: 10.1063/1.2746409

Seven L-phenylalanine based alkyl (monopolar) and alkanediyl (bipolar) derivatives are synthesized; while the bipolar urethane amides form gels and show strong adhesive properties, the monopolar analogues form fibrous nanoscopic cloth-like tapes.