Preparation methods,biological activities,and potential applications of marine algae oligosaccharides:a review

Marine algae are valuable sources of health-promoting molecules that have been consumed by Asians for decades.Among aquatic flora,marine algae stand out in terms of high content of marine algae polysaccharides(MAP)such as carrageenan,alginate,fucoidan,laminaran,agarose,rhamnan,and ulvan.When hydrolyzed,MAP generate marine algae oligosaccharides(MAO),which have attracted interest in recent years due to their superior solubility compared with MAP.Besides,MAO have been demonstrated numerous biological activities including antioxidant,antidiabetic,anti-inflammatory,antimicrobial,and prebiotic activities.Thus,this review summarizes the main chemical classes of MAO,their sources,and the main processes used for their production(i.e.,physical,chemical,and biological methods),coupled with a discussion of the advantages and disadvantages of these methods.Highlights of the biological activities of MAO and their potential applications in food,nutraceutical,and pharmaceuticals would also be discussed and summarized.

A Novel Method for the Prenatal Diagnosis of Cleft Palate Based on Amniotic Fluid Metabolites

Background and purpose The prenatal diagnosis of cleft palate is an important component of sequential therapy,but the relevant diagnostic methods are still limited.We aimed here,to explore the possibility of an early prenatal diagnosis of cleft palate by assessing metabolites in pregnant mice.Methods Twenty-four inseminated females were randomly divided into retinoic acid(RA)-treated(treated with retinoic acid at 10.5 gestation days)and control groups.The metabolites of the embryonic palatal tissue,maternal amniotic fluid,and serum were characterized using 9.4T magnetic resonance spectroscopy in vitro.Then,a predictive model was established through the principal component analysis(PCA),and the correlations between the metabolites of amniotic fluid and palatal tissue were explored using orthogonal-2 partial least squares(O2-PLS).Results The incidences of cleft palate were 100%and 0%in the RA-treated and control groups,respectively.A predictive PCA model with a high specificity and sensitivity was established for the early prenatal diagnosis of isolated cleft palate using amniotic fluid metabolic data.Between RA-treated and control mice,we found that two metabolites in the amniotic fluid and palatal tissue were correlated.Creatinine showed the same trend in the palatal tissue and amniotic fluid,while choline showed opposite trends in the two tissues.However,the data for serum metabolites could not be used to establish a prediction model.Conclusion This study indicates that assessing the metabolites of amniotic fluid is a potential approach for the prenatal diagnosis of isolated cleft palate.

Antibacterial polysaccharide-based hydrogel dressing containing plant essential oil for burn wound healing

Background:Polysaccharide-based hydrogels have been developed for many years to treat burn wounds.Essential oils extracted from aromatic plants generally exhibit superior biological activity,especially antibacterial properties.Studies have shown that antibacterial hydrogels mixed with essential oils have great potential for burn wound healing.This study aimed to develop an antibacterial polysaccharide-based hydrogel with essential oil for burn skin repair.Methods:Eucalyptus essential oil(EEO),ginger essential oil(GEO)and cumin essential oil(CEO)were employed for the preparation of effective antibacterial hydrogels physically crosslinked by carboxymethyl chitosan(CMC)and carbomer 940(CBM).Composite hydrogels were prepared and characterized using antimicrobial activity studies,Fourier-transform infrared spectroscopy,X-ray diffraction,scanning electron microscopy,gas chromatography-mass spectrometery,rheological analysis,viscosity,swelling,water loss rate and water vapor transmission rate studies.In addition,the biocompatibility of hydrogels was evaluated in vivo by cytotoxicity and cell migration assays and the burn healing ability of hydrogels was tested in vivo using burn-induced wounds in mice.Results:The different essential oils exhibited different mixing abilities with the hydrogel matrix(CMC and CBM),which caused varying levels of reduction in essential oil hydrogel viscosity,swelling and water vapor transmission.Among the developed hydrogels,the CBM/CMC/EEO hydrogel exhibited optimal antibacterial activities of 46.26±2.22%and 63.05±0.99%against Staphylococcus aureus and Escherichia coli,respectively,along with cell viability(>92.37%)and migration activity.Furthermore,the CBM/CMC/EEO hydrogel accelerated wound healing in mouse burn models by promoting the recovery of dermis and epidermis as observed using a hematoxylin–eosin and Masson’s trichrome staining assay.The findings from an enzyme-linked immunosorbent assay demonstrated that the CBM/CMC/EEO hydrogel could repair wounds through interleukin-6 and tumor necrosis factor-αdownregulation and transforming growth factor-β,vascular endothelial growth factor(VEGF)and epidermal growth factor upregulation.Conclusions:This study successfully prepared a porous CBM/CMC/EEO hydrogel with high antibacterial activity,favorable swelling,optimal rheological properties,superiorwater retention andwater vapor transmission performance and a significant effect on skin repair in vitro and in vivo.The results indicate that the CBM/CMC/EEO hydrogel has the potential for use as a promising burn dressing material for skin burn repair.

Poly(α-L-lysine)-based nanomaterials for versatile biomedical applications:Current advances and perspectives

Poly(α-L-lysine)(PLL)is a class of water-soluble,cationic biopolymer composed ofα-L-lysine structural units.The previous decade witnessed tremendous progress in the synthesis and biomedical applications of PLL and its composites.PLL-based polymers and copolymers,till date,have been extensively explored in the contexts such as antibacterial agents,gene/drug/protein delivery systems,bio-sensing,bio-imaging,and tissue engineering.This review aims to summarize the recent advances in PLL-based nanomaterials in these biomedical fields over the last decade.The review first describes the synthesis of PLL and its derivatives,followed by the main text of their recent biomedical applications and translational studies.Finally,the challenges and perspectives of PLL-based nanomaterials in biomedical fields are addressed.