Thursday, August 25, 2016

Co-development project with Hatch51 for commercially available 3DCellMaker bioprinting system

Akina, Inc. (www.polyscitech.com) has launched a joint project with additive engineering firm Hatch51 (http://hatch51.com/) for the creation of a 3D gel-printing system optimized for printing of Akina’s synthetic thermogelling 3DCellmaker. The printer will allow for low-temperature, gentle, printing of the thermogelling polymer solution so as to allow for printing of live-cell loaded solution to form 3D structures and tissues. Such a system has promise for a wide array of future applications. Those interested in the hardware portion of the system are encouraged to contact Hatch51 directly regarding this (contact@hatch51.com)

A recent review article details the possibilities of bio-printing and its applications. Read more here: Jakab, Karoly, Cyrille Norotte, Francoise Marga, Keith Murphy, Gordana Vunjak-Novakovic, and Gabor Forgacs. "Tissue engineering by self-assembly and bio-printing of living cells." Biofabrication 2, no. 2 (2010): 022001. http://iopscience.iop.org/article/10.1088/1758-5082/2/2/022001/meta


“Abstract: Biofabrication of living structures with desired topology and functionality requires the interdisciplinary effort of practitioners of the physical, life and engineering sciences. Such efforts are being undertaken in many laboratories around the world. Numerous approaches are pursued, such as those based on the use of natural or artificial scaffolds, decellularized cadaveric extracellular matrices and, most lately, bioprinting. To be successful in this endeavor, it is crucial to provide in vitro micro-environmental clues for the cells resembling those in the organism. Therefore, scaffolds, populated with differentiated cells or stem cells, of increasing complexity and sophistication are being fabricated. However, no matter how sophisticated scaffolds are, they can cause problems stemming from their degradation, eliciting immunogenic reactions and other a priori unforeseen complications. It is also being realized that ultimately the best approach might be to rely on the self-assembly and self-organizing properties of cells and tissues and the innate regenerative capability of the organism itself, not just simply prepare tissue and organ structures in vitro followed by their implantation. Here we briefly review the different strategies for the fabrication of three-dimensional biological structures, in particular bioprinting. We detail a fully biological, scaffoldless, print-based engineering approach that uses self-assembling multicellular units as bio-ink particles and employs early developmental morphogenetic principles, such as cell sorting and tissue fusion.”

Tuesday, August 23, 2016

PolyVivo biodegradable cross-linkable thermogel PLA-PEG-PLA diacrylate for reinforced 3D gel printing

Additive manufacturing, or 3D printing, has reimagined the way manufacturing is accomplished and brought in a new concept for prototype generation. Typical, polymer-melt printing, however is unsuitable for generation of tissue engineering products such as stem-cell seeded scaffolds or other bioactive materials. For this, 3D printing can be accomplished by printing a cold solution comprised of a thermosentive polymer dissolved in cell-growth media or other suitable aqueous solution onto a gently warmed platform (~37 °C). There are, however, drawbacks to this technique in that the thermogelation of polymers does not provide for high mechanical strength. To address this need, PolySciTech has launched PolyVivo AI145 (https://akinainc.com/polyscitech/products/polyvivo/?highlight=AI145#h). This is a thermogelling PLA-PEG-PLA with diacrylate endcaps that gels at 37 °C and allows for the gelled structures to be reinforced by photo-initiation of the acrylates to form a biodegradable crosslinked structure. Such a system could allow for 3D printing of cell-seeded thermogels with suitable mechanical requirements to allow for printing a structure with height and geometry not possible so far with conventional thermogelation 3D printing. A similar type process was applied by researchers in Tornio, Italy for generating a sol-gel printed substrate. This research holds promise for the development of reinforced tissue scaffolds for cellular growth or tissue repair as well as other engineered materials. Read more: Chiappone, Annalisa, Erika Fantino, Ignazio Roppolo, Massimo Lorusso, Diego Manfredi, Paolo Fino, Candido Fabrizio Pirri, and Flaviana Calignano. "3D Printed PEG-Based Hybrid Nanocomposites Obtained by Sol–Gel Technique." ACS applied materials & interfaces 8, no. 8 (2016): 5627-5633. http://pubs.acs.org/doi/abs/10.1021/acsami.5b12578


“In this work, three-dimensional (3D) structured hybrid materials were fabricated combining 3D printing technology with in situ generation of inorganic nanoparticles by sol–gel technique. Those materials, consisting of silica nanodomains covalently interconnected with organic polymers, were 3D printed in complex multilayered architectures, incorporating liquid silica precursors into a photocurable oligomer in the presence of suitable photoinitiators and exposing them to a digital light system. A post sol–gel treatment in acidic vapors allowed the in situ generation of the inorganic phase in a dedicated step. This method allows to build hybrid structures operating with a full liquid formulation without meeting the drawbacks of incorporating inorganic powders into 3D printable formulations. The influence of the generated silica nanoparticle on the printed objects was deeply investigated at macro- and nanoscale; the resulting light hybrid structures show improved mechanical properties and, thus, have a huge potential for applications in a variety of advanced technologies. Keywords: 3D printing; digital light processing (DLP); hybrid nanocomposite; mechanical properties; sol−gel”


Monday, August 22, 2016

Polydioxanone used for cellular alignment study to understand Muscle tissue regeneration


PolySciTech division of Akina, Inc. (www.polyscitech.com) provides a wide array of biodegradable polymers. Recently, poly(dioxanone) (PDO) was added to this list with pilot product PolyVivo AP186. This polymer has been used in research to elucidate the effect of alignment in cell signaling. This research is crucial to creating functional muscle regeneration scaffolds. Read more: McClure, Michael J., Nicholas M. Clark, Sharon L. Hyzy, Charles E. Chalfant, Rene Olivares-Navarrete, Barbara D. Boyan, and Zvi Schwartz. "Role of integrin α7β1 signaling in myoblast differentiation on aligned polydioxanone scaffolds." Acta biomaterialia (2016). http://www.sciencedirect.com/science/article/pii/S1742706116302082


“Abstract: The aligned structural environment in skeletal muscle is believed to be a crucial component in functional muscle regeneration. Myotube formation is increased on aligned biomaterials, but we do not fully understand the mechanisms that direct this enhanced fusion. Previous studies indicate that the α7 integrin subunit is upregulated during myoblast differentiation, suggesting that signaling via α7β1 mediates the effect of alignment. To test this hypothesis, we took advantage of an in vitro model using random and aligned polydioxanone (PDO) matrices and C2C12 myoblasts. We measured expression and production of myoblast markers: paired box-7 (Pax7), myogenic differentiation factor-1 (MyoD), myogenin (MyoG), myogenic factor-6 (Myf6), and myosin heavy chain (MyHC). To examine the role of α7β1 signaling, we measured expression and production of α7, α5, and β1 and myoblast markers in wild type cells and in cells silenced for α7 and assessed effects of silencing on myogenic differentiation. Downstream signaling via ERK1/2 mitogen activated protein kinase (MAPK) was examined using a specific MEK1/2 inhibitor. Alignment increased mRNAs and protein for early (MyoD) and late (MyoG, MyHC) myoblast markers in comparison to non-aligned matrices, and these levels corresponded with increased α7 protein. α7-silencing reduced MyoG and MyHC protein in cells cultured on tissue culture polystyrene and aligned PDO matrices compared to wild type cells. Inhibition of ERK1/2 blocked effects of alignment. These data suggest that alignment regulates myogenic differentiation via α7β1 integrin signaling and ERK1/2 mediated gene expression. Statement of Significance: Muscle regeneration in severe muscle injuries is complex, requiring a sequence of events to promote healing and not fibrosis. Aligned biomaterials that recapitulate muscle environments hold potential to facilitate regeneration, but it is important to understand cell-substrate signaling to form functional muscle. A critical component of muscle signaling is integrin α7β1, where mice lacking α7 exhibit a dystrophic phenotype and impaired regeneration. Here, we report the role of α7β1 signaling in myoblast differentiation on aligned biomaterials. α7-silenced myoblasts were found to regulate myogenic differentiation and demonstrate defective fusion. Our data shows reduced levels of myogenin and myosin heavy chain protein, while MyoD remains unchanged. These results support the hypothesis that α7β1 signaling plays a role in substrate-dependent tissue engineering strategies. Keywords: Muscle; Polydioxanone fiber alignment; Surface topography; Biomimetic material; Myoblast differentiation”

Wednesday, August 17, 2016

PEG-PLA used in development of nanoparticle delivered cancer immunotherapy

PolySciTech division of Akina, Inc. (www.polyscitech.com) provides a wide array of biodegradable block copolymers including PEG-PLA. One of the more insidious facets of cancer is its ability to either disarm or bypass the human immune system. An attractive chemotherapeutic target is to disable this ability so that the human immune system attacks cancer cells the same way it would attack an infection. Such a technique has advantages over conventional anti-proliferative chemotherapeutic agents (such as paclitaxel) as it is specific in its activity against cancer cells. Recently PEG-PLA block polymer was used by researchers to deliver siRNA to T-cells rendering them active against cancer cells. This research holds promise to develop a ‘cancer vaccine’ so that the body’s immune system can fight the cancer off with much greater safety and efficacy than conventional chemotherapy. Read more: Hosseini, Maryam, Mostafa Haji-Fatahaliha, Farhad Jadidi-Niaragh, Jafar Majidi, and Mehdi Yousefi. "The use of nanoparticles as a promising therapeutic approach in cancer immunotherapy." Artificial cells, nanomedicine, and biotechnology 44, no. 4 (2016): 1051-1061. http://www.tandfonline.com/doi/abs/10.3109/21691401.2014.998830

“Abstract: The core purpose of cancer immunotherapy is the sustained activation and expansion of the tumor specific T cells, especially tumor-infiltrating cytotoxic T lymphocytes (CTLs). Currently, one of the main foci of immunotherapy involving nano-sized carriers is on cancer vaccines and the role of professional antigen presenting cells, such as dendritic cells (DCs) and other phagocytic immune cells. Besides the idea that cancer vaccines promote T cell immune responses, targeting immune inhibitory pathways with nanoparticle delivered regulatory agents such as small interfering RNA (siRNA) to the difficultly-transfected tumor-infiltrating T cells may provide more information on the utility of nanoparticle-mediated cancer immunotherapy. In this study, we constructed nanoparticles to deliver cytotoxic T lymphocyte-associated molecule-4 (CTLA-4)-siRNA (NPsiCTLA-4) and showed the ability of this siRNA delivery system to enter T cells both in vitro and in vivo. Furthermore, T cell activation and proliferation were enhanced after NPsiCTLA-4 treatment in vitro. The ability of direct regulation of T cells of this CTLA-4 delivery system was assessed in a mouse model bearing B16 melanoma. Our results demonstrated that this nanoparticle delivery system was able to deliver CTLA-4-siRNA into both CD4+ and CD8+ T cell subsets at tumor sites and significantly increased the percentage of anti-tumor CD8+ T cells, while it decreased the ratio of inhibitory T regulatory cells (Tregs) among tumor infiltrating lymphocytes (TILs), resulting in augmented activation and anti-tumor immune responses of the tumor-infiltrating T cells. These data support the use of potent nanoparticle-based cancer immunotherapy for melanoma. Graphical abstract: T cell mediated immunotherapy is an effective treatment option for malignant melanoma. It is critical for such immunotherapy to obtain a sufficient number of functional/activated T cells. However, CTLA-4 plays a potent inhibitory role in T cell activation and proliferation, which significantly curbs T cell-mediated tumor rejection. Hence, we investigated a method to exploit a nanoparticle delivery system to efficiently deliver siRNA (NPsiCTLA-4) targeting an immune checkpoint molecule, i.e. cytotoxic T lymphocyte-associated molecule-4, to manipulate or modulate tumor-infiltrating T cells and to assess the effects of NPsiCTLA4 on the blockade of CTLA-4 and the resulting enhancement of T cell mediated anti-tumor immunotherapy. Keywords: Cancer immunotherapy; Nanoparticle; Tumor-infiltrating T cells; Cytotoxic T lymphocyte-associated molecule-4 (CTLA-4)”

Monday, August 15, 2016

Two types of PLGA from PolySciTech used in development of directional Resolvin delivery-system for improved cardiac care

PolySciTech Division of Akina, Inc. (www.polyscitech.com) provides a wide array of biodegradable polymers for several applications. One of these is PLGA type polymers including a wide array of molecular weights and lactide:glycolide ratios. For this type of polymer, the degradation time increases as the lactide content increases. This allows different types of PLGA to be combined in specific orientations so as to encourage degradation or drug release to preferentially occur on one side. Recently, two PLGA polymers from PolySciTech with different lactide contents (AP061 (LA:GA 75:25 (Mn 35-45 kDa)) and AP021 (85:15 (Mn 35-45 kDa))) were utilized by researchers at UCSF to design a system which delivers Resolvin D1, a mediator which promotes injury recovery, in a directional manner from a thin film with 98% of the resolvin released through the low-lactide side over the course of 56 days. Such a system holds promise for use in cardiac therapy to prevent restenosis of arteries following stenting or other procedures. Read more: Lance, Kevin D., Anuran Chatterjee, Bian Wu, Giorgio Mottola, Harald Nuhn, Phin Peng Lee, Brian E. Sansbury, Matthew Spite, Tejal A. Desai, and Michael S. Conte. "Unidirectional and Sustained Delivery of the ProResolving Lipid Mediator Resolvin D1 from a Biodegradable Thin Film Device." Journal of Biomedical Materials Research Part A (2016). http://onlinelibrary.wiley.com/doi/10.1002/jbm.a.35861/full

“Abstract: Resolvin D1 (RvD1) belongs to a family of endogenously derived pro-resolving lipid mediators that have been shown to attenuate inflammation, activate pro-resolution signaling and promote homeostasis and recovery from tissue injury. In this study we present a poly(lactic-co-glycolic acid) (PLGA) based thin-film device composed of layers of varying ratios of lactic and glycolic acid that elutes RvD1 unidirectionally to target tissues. The device demonstrated sustained release in vitro for 56 days with an initial burst of release over 14 days. The asymmetric design of the device released 98% of RvD1 through the layer with the lowest molar ratio of lactic acid to glycolic acid, and the remainder through the opposite side. We validated structural integrity of RvD1 released from the device by mass spectrometry and investigated its bioactivity on human vascular endothelial (EC) and smooth muscle cells (VSMC). RvD1 released from the device attenuated VSMC migration, proliferation and TNF-α induced NF-κB activation, without evidence of cytotoxicity. Delivery of RvD1 to blood vessels was demonstrated ex vivo in a flow chamber system using perfused rabbit aortas and in vivo in a rat carotid artery model, with the devices applied as an adventitial wrap. Our results demonstrate a novel approach for sustained, local delivery of Resolvin D1 to vascular tissue at therapeutically relevant levels. Keywords: PLGA; resolvin; inflammation; vascular delivery; wrap”

Monday, August 8, 2016

PLGA from PolySciTech used for development of nanoparticle stability model to prevent lethal clogs in blood-stream

PolySciTech division of Akina, Inc (www.polyscitech.com) provides a wide array of biodegradable polymers including PLGA. Recently, PLGA from PolySciTech (PolyVivo AP082) was used to generate model nanoparticles for validating a system developed to determine nanoparticle colloidal stability. This research allows for a tool which ensures nanoparticles will not collect up and clog in a biological system thus improving the safety of using nanoparticles to deliver medicines. Read more: Shaikh, Muhammad Vaseem, Manika Kala, and Manish Nivsarkar. "Development and Optimization of an Ex Vivo Colloidal Stability Model for Nanoformulations." AAPS PharmSciTech: 1-5. http://link.springer.com/article/10.1208/s12249-016-0597-9


“Abstract: Nanotechnology is having a significant impact in the drug delivery systems and diagnostic devices. As most of the nanosystems are intended to be administered in vivo, there is a need for stability models, which could simulate the biological environment. Instability issues could lead to particle aggregation and in turn could affect the release of the drug from the nanosystems and even lead to clogging of the systemic blood circulation leading to life-threatening situation. We have developed an ex vivo colloidal stability model for testing the stability of nanosystems over a period of 48 h, which is the typical residence time of the nanoparticles in vivo. Tissue homogenates of rat spleen, brain, kidney, and liver were stabilized and optimized for the study; additionally, plasma and serum were used for the same. Poly (lactide-co-glycolic acid) nanoparticles were used as model nanosystem, and no significant change was found in the size and polydispersity index of the nanoparticles in the biological solutions. Moreover, no change in morphology was observed after 48 h as observed by TEM microscopy. Hence, the developed model could prevent the failure of the developed nanosystem during clinical and preclinical application by serving as an initial checkpoint to study their interaction with the complex milieu. Keywords:ex vivo colloidal stability PLGA nanoparticle nanosystem”

Friday, August 5, 2016

PLGA-PEG-PLGA from PolySciTech used for assaying nanoparticle interactions with proteins

PolySciTech division of Akina, Inc. (www.polyscitech.com) provides a wide variety of block copolymers including PLGA-PEG-PLGA. Recently, PLGA-PEG-PLGA from Akina, Inc. was purchased (PolyVivo Catalog#: AK032 and Catalog#: AK017) and used for testing Albumin interaction with these nanoparticles. They confirmed the importance of PEG’s steric hinderance for preventing protein adsorption to nanoparticle. Read more: Geskovski, Nikola, Simona Dimchevska, Rozafa Koliqi, Gjorgji Petruševski, Marina Chacorovska, Sonja Ugarkovic, and Katerina Goracinova. "A spectroscopic insight into the albumin structure on the nano-bio interface." Your hosts Macedonian Pharmaceutical Association and Faculty of Pharmacy, Ss Cyril and Methodius University in Skopje: 367. https://www.researchgate.net/profile/Irina_Mladenoska/publication/304577752_Effect_of_glucose_concentration_on_glucose_oxidase_activity_in_a_minimal_model_must/links/5773d3e908aeb9427e241721.pdf#page=367


“Synopsis (* quotes compiled from paper sections): It is becoming clear that, when placed into a biological environment, nanoparticles initiate a cascade of interactions with the biomacromolecules resulting in the formation of the ‘protein corona’ (a layer(s) of proteins adsorbed on the nanoparticles surface) (Monopoli et al., 2011). These interactions can alter the secondary structure of the adsorbed proteins promoting instability and/or exposure of new epitopes at the protein surface, thus giving rise to unexpected biological responses (Calzolai et al., 2010). PLGA-PEO-PLGA (Mw 148KDa and Mw 22KDa) was purchased from Akina Inc (USA). Nanoparticle formulations were prepared from PLGAPEO-PLGA (Mw 70,000:8,000:70,000Da) – NP1 and PLGA-PEO-PLGA (Mw 6,000:10,000:6,000Da) – NP2, using the nanoprecipitation method, as described previously All samples were diluted to concentration of 2mg/ml and subsequently 1ml from each formulation was mixed with 1ml of 2mg/mL BSA solution in phosphate buffer (pH 7.4). The NP dispersions with BSA were incubated for 1h at 37°C in a water bath with horizontal shaking at 100 min- 1. After the incubation, the samples were concentrated to 1mL using ultrafiltration tubes with pore size of 1000 kDa, and washed with phosphate buffer pH 7.4. Blank (BSA free) and control sample (without nanoparticles) were also used in the experiment. The amount of adsorbed BSA was indirectly quantified using the Bradford protein assay. The results from the quantitative BSA adsorption studies revealed that 24.6±1.9 and 13.1±0.9% of BSA were adsorbed on the surface of NP1 and NP2, respectively. The results unambiguously point to the effect of the hydrophilic outer nanoparticle layer as a steric barrier for nanoparticle-BSA interactions.”