Biocompatibility of intraperitoneally implanted TEMPO-oxidized cellulose nanofiber hydrogels for antigen delivery in Atlantic salmon (Salmo salar L.) vaccines.

Disease outbreaks are a major impediment to aquaculture production, and vaccines are integral for disease management. Vaccines can be expensive, vary in effectiveness, and come with adjuvant-induced adverse effects, causing fish welfare issues and negative economic impacts. Three-dimensional biopolymer hydrogels are an appealing new technology for vaccine delivery in aquaculture, with the potential for controlled release of multiple immunomodulators and antigens simultaneously, action as local depots, and tunable surface properties. This research examined the intraperitoneal implantation of a cross-linked TEMPO cellulose nanofiber (TOCNF) hydrogel formulated with a Vibrio anguillarum bacterin in Atlantic salmon with macroscopic and microscopic monitoring to 600-degree days post-implantation. Results demonstrated a modified passive integrated transponder tagging (PITT) device allowed for implantation of the hydrogel. However, the Atlantic salmon implanted with TOCNF hydrogels exhibited a significant foreign body response (FBR) compared to sham-injected negative controls. The FBR was characterized by gross and microscopic external and visceral proliferative lesions, granulomas, adhesions, and fibrosis surrounding the hydrogel using Speilberg scoring of the peritoneum and histopathology of the body wall and coelom. Acutely, gross monitoring displayed rapid coagulation of blood in response to the implantation wound with development of fibrinous adhesions surrounding the hydrogel by 72 h post-implantation consistent with early stage FBR. While these results were undesirable for aquaculture vaccines, this work informs on the innate immune response to an implanted biopolymer hydrogel in Atlantic salmon and directs future research using cellulose nanomaterial formulations in Atlantic salmon for a new generation of aquaculture vaccine technology.

Cultured Meat Safety Research Priorities: Regulatory and Governmental Perspectives.

As with every new technology, safety demonstration is a critical component of bringing products to market and gaining public acceptance for cultured meat and seafood. This manuscript develops research priorities from the findings of a series of interviews and workshops with governmental scientists and regulators from food safety agencies in fifteen jurisdictions globally. The interviews and workshops aimed to identify the key safety questions and priority areas of research. Participants raised questions about which aspects of cultured meat and seafood production are novel, and the implications of the paucity of public information on the topic. Novel parameters and targets may require the development of new analytical methods or adaptation and validation of existing ones, including for a diversity of product types and processes. Participants emphasized that data sharing of these efforts would be valuable, similar to those already developed and used in the food and pharmaceutical fields. Contributions to such databases from the private and public sectors would speed general understanding as well as efforts to make evaluations more efficient. In turn, these resources, combined with transparent risk assessment, will be critical elements of building consumer trust in cultured meat and seafood products.

One-step hydrothermal synthesis with in situ milling of biologically relevant hydroxyapatite.

Biologically relevant synthetic hydroxyapatite (HA) has become a much-desired material for use within the medical field with an emphasis on orthopedic applications. However, there are very few sources of sub-micron scale HA powders that are economical. Many current procedures to generate synthetic HA, that is both biological and chemically analogous to naturally occurring HA, tend to involve complicated synthesis procedures that are difficult to simultaneously produce desired stoichiometric ratios and particle diameter. This paper reports the development of a one-step hydrothermal method with in situ ball milling of synthetic HA. That has the potential to be a biological substitute with similar calcium to phosphate stoichiometric ratio and particle diameter of HA found in many natural biologically occulting sources. Parameters affecting particle diameter investigated included varying ball milling media, in situ and ex situ ball milling, and simultaneous agitation. The stoichiometric ratios of the resulting powders indicated that 4-hour hydrothermal reaction time produced materials that are analogous to natural HA, confirmed from spectra acquired via Fourier Transform Infrared spectroscopy (FT-IR). X-ray diffraction and Scanning Electron Microscopy both indicate that the predominant size of primary crystallites is around ~25 nm. Particle size distributions of dried in situ ball-milled HA suggest that primary crystallites exist as aggregates, with aggregate diameters ranging between 1 and 100 µm.