The platelet-rich plasma (PRP) is an autologous biotherapy based on platelet-healing properties. Here, we developed a simple and reproducible PRP purification protocol based on two successive centrifugations. We evaluated different centrifugation speeds and time-storage durations on the platelet quantity and quality. Sterility and stability of our PRP homemade product were also performed. We prepared PRP from 54 healthy volunteers. We tested activation state, reactivity, and stability of platelets by flow cytometry using basal and adenosine diphosphate (ADP)-induced P-selectin expression markers; growth factor release after platelet activation by an enzyme-linked immunosorbent assay (ELISA); platelet aggregation capacity by aggregrometry assays; clot formation and retraction by thromboelastography; and platelet morphology by ultrastructural analysis. About 130 and 250 g successive speed centrifugations further concentrated platelets while preserving their bioactivity during 6 h (after that, platelet functions were significantly altered). In these conditions, we obtained a highly concentrated pure PRP product (with a low leukocyte count) suitable to study platelet properties. To avoid the loss of efficacy, we recommend injecting PRP under 3 h after preparation.

It is my pleasure to introduce the inaugural issue of the first peer-reviewed, fully open access journal from Mary Ann Liebert, Inc., publishers. The scientific community has been abuzz with enthusiasm about open access, but with some legitimate concerns about the credibility of some of those journals from less reputable publishers and the level of peer review—or lack thereof—for open access articles. We are taking a unique approach with BioResearch Open Access to address these concerns and guarantee expert review. The strength of our editorial team lies in the unique input from our highly experienced Section Editors, each of whom is the Editor of a leading journal in his or her own field and who recommend articles for publication. The Journal also welcomes unsolicited articles. BioResearch Open Access is a fully peer-reviewed journal, ensuring that the quality and integrity of articles is maintained. I am delighted to acknowledge the support and participation from the following Section Editors: Stephen C. Ekker, PhD Mayo Addiction Research Center, Mayo Clinic, Rochester, Minnesota Domenico Grasso, PhD, PE, DEE The University of Vermont, Burlington, Vermont Aubrey D.N.J. de Grey, PhD SENS Foundation, Cambridge, United Kingdom Stephen Higgs, PhD, FRES Biosecurity Research Institute, Kansas State University, Manhattan, Kansas Thomas Hope, PhD Northwestern University, Chicago, Illinois Peter C. Johnson, MD Scintellix, LLC, Raleigh, North Carolina Eugene Kolker, PhD Chief Data Officer, Seattle Children's Hospital, Seattle, Washington Antonios G. Mikos, PhD Rice University, Houston, Texas Graham C. Parker, PhD Wayne State University School of Medicine, Detroit, Michigan Carol Shoshkes Reiss, PhD New York University, New York, New York Alan J. Russell, PhD Carnegie Mellon University, Pittsburgh, Pennsylvania Ganes C. Sen, PhD Cleveland Clinic Foundation, Cleveland, Ohio Bruce A. Sullenger, PhD Duke University Medical Center, Durham, North Carolina John B. West, MD, PhD University of California, San Diego, La Jolla, California David L. Woodland, PhD Keystone Symposia on Molecular and Cellular Biology, Silverthorne, Colorado Professor Sir Ian Wilmut, OBE, FRS, FRSE MRC Centre for Regenerative Medicine, Scottish Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, United Kingdom James M. Wilson, MD, PhD University of Pennsylvania, Philadelphia, Pennsylvania The Journal provides a new rapid-publication forum for a broad range of scientific topics, including, but not limited to, molecular and cellular biology, tissue engineering and biomaterials, regenerative medicine, bioengineering, stem cells, gene therapy, systems biology, genetics, biochemistry, virology, microbiology, and neuroscience. The purpose of this publication is to create a forum to bring together research from all aspects of biomedical research through open access. This first issue (Volume 1, Issue 1) has accomplished this goal by providing six research articles from internationally acclaimed research groups: Reovirus-Mediated Cytotoxicity and Enhancement of Innate Immune Responses Against Acute Myeloid Leukemia (University of Leeds, Leeds, United Kingdom) Differentiation of Human Neural Progenitor Cells in Functionalized Hydrogel Matrices (University of Rostock, Rostock, Germany) Permeability of 3D Fibrin Constructs Corresponds to Fibrinogen and Thrombin Concentrations (University of California, Los Angeles, California) Human Skin Cells That Express Stage-Specific Embryonic Antigen 3 Associate with Dermal Tissue Regeneration (University of California, Los Angeles, California) Phylogenetic Analysis of the Earliest nef Gene from Hemophiliacs and Local Controls in Korea (University of Ulsan, Ulsan, Korea) The Effect of Biological and Synthetic Matrices on Hepatic Stem Cell Gene Expression (University of Edinburgh, Edinburgh, United Kingdom) We would like to thank the authors who submitted their work to this new journal and hope that this collection of articles makes them pleased to be a part of the first issue. BioResearch Open Access welcomes basic science and translational research in the form of original research articles, comprehensive review articles, minireviews, rapid communications, brief reports, technology reports, hypothesis articles, perspectives, and letters to the editor. All research articles in BioResearch Open Access will be published online within 4 weeks of acceptance. Articles will be fully open access and posted on PubMedCentral, and the Journal is fully NIH-, HHMI-, and Wellcome Trust–compliant. Instructions for Authors and further information are available at www.liebertpub.com/biores We hope that this new venture will provide a stimulating forum for biomedical research and discussion, and we welcome your active participation and article submissions.

Research in the last few years have focused on the use of three-dimensional (3D) fibrin construct to deliver growth factors and cells. Three-dimensional construct permeability and porosity are important aspects for proper nutrient uptake, gas exchange, and waste removal—factors that are critical for cell growth and survival. We have previously reported that the mechanical strength (stiffness) of 3D fibrin constructs is dependent on the fibrinogen and thrombin concentration. In this study, we established two new in vitro models to examine how fibrin composition affects the final 3D fibrin construct permeability and pore size; thereby, influencing the diffusivity of macromolecules throughout the network of fibrin fibrils. Flow measurements of both liquid and fluoresceinated-dextran microparticles are conducted to calculate the permeability and pore size of 3D fibrin constructs of different fibrinogen and thrombin concentrations. Similarly, the diffusivity of liquid and fluoresceinated-dextran microparticles through these 3D fibrin constructs are determined through diffusion models. Data from these studies show that the structural permeability and pore size of 3D fibrin constructs directly correlate to fibrinogen and thrombin concentration in the final 3D fibrin construct. More specifically, at a constant thrombin concentration of 2 or 5 μ/mL, pore size of the 3D fibrin constructs is dependent on fibrinogen if the concentration is 5 mg/mL and to a lesser extent if the concentration is 10–15 mg/mL. These findings suggest that fibrin's diffusive property can be manipulated to fabricate 3D constructs that are optimized for cellular growth, protein transport, and for the controlled delivery of bioactive molecules such as growth factors.