3D-Printed Hybrid Collagen/GelMA Hydrogels for Tissue Engineering Applications

Bioprinting is an emerging technology involved in the fabrication of three-dimensional tissue constructs for the repair and regeneration of various tissues and organs. Collagen, a natural protein found abundantly in the extracellular matrix of several tissues, can be extracted from collagen-rich tissues of animals such as sheep, cows, rats, pigs, horses, birds, and marine animals. However, due to the poor printability of collagen bioinks, biocompatible collagen scaffolds that mimic the extracellular matrix (ECM) are difficult to fabricate using bioprinting techniques. Gelatin methacrylate (GelMA), a semi-synthetic polymer with tunable physical and chemical properties, has been found to be a promising biomaterial in various bioprinting applications. The printability of collagen can be improved by combining it with semi-synthetic polymers such as GelMA to develop hybrid hydrogels. Such hybrid hydrogels printed have also been identified to have enhanced mechanical properties. Hybrid GelMA meshes have not previously been prepared with collagen from ovine sources. This study provides a novel comparison between the properties of hybrid meshes with ovine skin and bovine hide collagen. GelMA (8% w/v) was integrated with three different concentrations (0.5%, 1%, and 2%) of bovine and ovine collagen forming hybrid hydrogels inks that were printed into meshes with enhanced properties. The maximum percentage of collagen suitable for integration with GelMA, forming hybrid hydrogels with a stable degradation rate was 1%. The water-soluble nature of ovine collagen promoted faster degradation of the hybrid meshes, although the structural crosslinking was identified to be higher than bovine hybrid meshes. The 1% bovine collagen hybrid meshes stood out in terms of their stable degradation rates

The effectiveness of naltrexone combined with current smoking cessation medication to attenuate post smoking cessation weight gain: a literature review

Abstract Background Smoking is the number one cause of preventable morbidity and mortality globally and although many countries have invested heavily in smoking cessation programs, 21% of the global population still smoke. Post cessation weight gain has been identified as a barrier to attempting cessation and is implicated in the high rates of relapse. Naltrexone has been touted as a possible solution to address post smoking cessation weight gain. Results The results from seven original studies assessing the effectiveness of naltrexone in combination with existing smoking cessation medications to attenuate post smoking cessation weight gain were obtained and critically reviewed. Five returned positive results and two returned results that were statistically insignificant. The positive results were seen more often in those identified as more likely to exhibit hedonic eating behaviour for example women and participants who were categorised as overweight or obese. Conclusion The evidence suggests further investigation in to a combination of naltrexone and approved smoking cessation medications is warranted and could provide a solution to attenuate post smoking cessation weight gain especially in women and those classified as overweight or obese. This may provide the tool required to remove a perceived barrier to smoking cessation and improve global statistics

Effect of Dietary Insect Meal and Grape Marc Inclusion on Flavor Volatile Compounds and Shell Color of Juvenile Abalone Haliotis iris

Almost 60% of the fish meal produced globally is used in aquaculture feeds. Fish meal production relies on finite wild-marine resources and is considered as an unsustainable ingredient. Insect meal (IM) is considered a sustainable source with high levels of protein suitable for growth promotion. Grape marc (GM) is a waste byproduct of the winery industry rich in pigments with antioxidant capacity. However, the inclusion of both ingredients can affect the flavor of the meat of abalone and the color of the shell due to different nutritional profiles. The aim of this study was to evaluate the effect of the dietary inclusion of IM and GM on the flavor volatile compounds and shell color of the juvenile Haliotis iris in a 165-days feeding trial. Abalone were offered four experimental diets with different levels of IM and GM inclusion and a commercial diet (no IM or GM). Soft bodies of abalone were used to characterize volatile compounds using solid-phase microextraction gas chromatography–mass spectrometry, and color changes were analyzed in ground powder of abalone shells using color spectrophotometry 400–700 nm (visible). The results showed 18 volatile compounds significantly different among the dietary treatments. The inclusion of IM did not significantly affect the flavor volatile compounds detected, whereas the inclusion of GM reduced volatile compounds associated with lipid-peroxidation in abalone meat. The inclusion of IM and GM did not significantly affect the lightness nor the yellowness, blueness, redness, and greenness of the ground shells. The supplementation of abalone feeds with GM can help to reduce off-flavour compounds which may extend shelf-life of raw abalone meat

Dual platform based sandwich assay surface-enhanced Raman scattering DNA biosensor for the sensitive detection of food adulteration

Surface enhanced Raman scattering (SERS) DNA biosensing is an ultrasensitive, selective, and rapid detection technique with the ability to produce molecule-specific distinct fingerprint spectra. It supersedes the long amplicon based PCR assays, the fluorescence and spectroscopic techniques with their quenching and narrow spectral bandwidth, and the electrochemical detection techniques using multiplexing. However, the performance of the SERS DNA biosensor relies on the DNA probe length, platform composition, both the presence and position of Raman tags and the chosen sensing strategy. In this context, we herein report a SERS biosensor based on dual nanoplatforms with a uniquely designed Raman tag (ATTO Rho6G) intercalated short-length DNA probe for the sensitive detection of the pig species Sus scrofa. In the design of the signal probe (SP), a Raman tag was incorporated adjacent to the spacer arm, followed by a terminal thiol modifier, which consequently had a strong influence on the SERS signal enhancement. The detection strategy involves the probe-target DNA hybridization mediated coupling of the two platforms, i.e., the graphene oxide-gold nanorod (GO-AuNR) functionalized capture probe (CP) and SP-conjugated gold nanoparticles (AuNPs), consequently enhancing the SERS intensity by both the electromagnetic hot spots generated at the junctions or interstices of the two platforms and the chemical enhancement between the AuNPs and the adsorbed intercalated Raman tag. This dual platform based SERS DNA biosensor exhibited outstanding sensitivity in detecting pork DNA with a limit of detection (LOD) of 100 aM validated with DNA extracted from a pork sample (LOD 1 fM). Moreover, the fabricated SERS biosensor showed outstanding selectivity and specificity for differentiating the DNA sequences of six closely related non-target species from the target DNA sequences with single and three nucleotide base-mismatches. Therefore, the developed short-length DNA linked dual platform based SERS biosensor could replace the less sensitive traditional methods of pork DNA detection and be adopted as a universal detection approach for the qualitative and quantitative detection of DNA from any source

Consumer Acceptance and Production of In Vitro Meat: A Review

In vitro meat (IVM) is a recent development in the production of sustainable food. The consumer perception of IVM has a strong impact on the commercial success of IVM. Hence this review examines existing studies related to consumer concerns, acceptance and uncertainty of IVM. This will help create better marketing strategies for IVM-producing companies in the future. In addition, IVM production is described in terms of the types of cells and culture conditions employed. The applications of self-organising, scaffolding, and 3D printing techniques to produce IVM are also discussed. As the conditions for IVM production are controlled and can be manipulated, it will be feasible to produce a chemically safe and disease-free meat with improved consumer acceptance on a sustainable basis

Phase transition of a microemulsion upon addition of cyclodextrin – applications in drug delivery

<p>This study reports on the impact of cyclodextrin addition on the phase behavior of microemulsion systems. Three distinct oil-in-water microemulsions were formulated and subjected to increasing concentrations of various cyclodextrins. The prepared formulations underwent visual, textural and microscopic characterization followed by the evaluation of their <i>in vitro</i> drug release and <i>ex vivo</i> tissue retention behavior. Combining microemulsions with cyclodextrins resulted in either phase separation or transition into a liquid crystalline state depending on the concentration and type of cyclodextrin utilized. Formulations combined with α-cyclodextrin consistently demonstrated transition into a liquid crystalline state as confirmed by polarized light and cryo-scanning electron microscopy. In these cases, cyclodextrin addition was also positively correlated with an increase in formulation hardness, adhesiveness and turbidity. Release and clearance studies revealed that drug diffusion from the microemulsions could be slowed and tissue retention prolonged by increasing the cyclodextrin content. These findings pave the way for the development of novel cyclodextrin-microemulsion-based liquid crystalline formulations in a variety of sustained drug delivery applications.</p