Polysucrose hydrogel loaded with natural molecules/extracts for multiphase-directed sustainable wound healing

Natural molecules/extracts have numerous beneficial effects on wound healing processes which are challenged by appropriate use and non-toxic dosage. Polysucrose-based (PSucMA) hydrogels have been synthesized with in situ loading of one or more natural molecules/extracts namely Manuka honey (MH), Eucalyptus honey (EH1, EH2), Ginkgo biloba (GK), thymol (THY) and metformin (MET). EH1 presented low amounts of hydroxymethylfurfural and methylglyoxal compared to MH indicating that EH1 was not temperature-abused. It also showed high diastase activity and conductivity. GK was added to PSucMA solution along with other additives including MH, EH1 and MET and crosslinked to form dual loaded hydrogels. The in vitro release profiles of EH1, MH, GK and THY from the hydrogels followed the exponential Korsmeyer-Peppas equation, with a release exponent value of less than 0.5 indicating a quasi-Fickian diffusion mechanism. The IC50 values of these natural products using L929 fibroblasts and RAW 264.7 macrophages indicated that EH1, MH and GK were cytocompatible at relatively high concentrations compared to MET, THY and curcumin used as a control. MH and EH1 induced high IL6 concentration compared to GK. In vitro studies were modelled to mimic the overlapping wound healing phases using human dermal fibroblasts (HDFs), macrophages and human umbilical endothelial cells (HUVECs) in dual culture. HDFs showed a highly interconnected cellular network on GK loaded scaffolds. EH1 loaded scaffolds were seen to induce formation of spheroids which increased in number and size in co-culture studies. The SEM images of HDF/HUVEC seeded GK, GKMH and GKEH1 loaded hydrogels indicated formation of vacuoles and lumen structures. These results indicated that a combination of GK and EH1 in the hydrogel scaffold would accelerate tissue regeneration by acting on the four overlapping phases of wound healing.

Electrospun polydioxanone/fucoidan blend nanofibers loaded with anti-cancer precipitate from Jaspis diastra and paclitaxel: Physico-chemical characterization and in-vitro screening

Nanofibers for drug delivery systems have gained much attention during the past years. This paper describes for the first time the loading of a bioactive precipitate (JAD) from the marine sponge Jaspis diastra in PDX and fucoidan-PDX. JAD was characterized by LC-MS/MS and the major component was jaspamide (1) with a purity of 62.66 %. The cytotoxicity of JAD was compared with paclitaxel (PTX). JAD and PTX displayed IC50 values of 1.10 ± 0.7 μg/mL and 0.21 ± 0.12 μg/mL on skin fibroblasts L929 cells whilst their IC50 values on uveal MP41 cancer cells, were 2.10 ± 0.55 μg/mL and 1.38 ± 0.68 μg/mL, respectively. JAD was found to be less cytotoxic to healthy fibroblasts compared to PTX. JAD and PTX loaded scaffolds showed sustained release over 96 h in physiological medium which is likely to reduce the secondary cytotoxic effect induced by JAD and PTX alone. The physico-chemical properties of the loaded and unloaded scaffolds together with their degradation and action on tumor microenvironment by using L929 and MP41 cells were investigated. JAD and PTX at a concentration of 0.5 % (drug/polymer, w/w) in the electrospun mats prevented growth and proliferation of L929 and MP41 cells. Co-culture of L929 and MP41 showed that the JAD and PTX loaded mats inhibited the growth of both cells and caused cell death.

Predicting inflammatory response of biomimetic nanofibre scaffolds for tissue regeneration using machine learning and graph theory

Tissue regeneration after a wound occurs through three main overlapping and interrelated stages namely inflammatory, proliferative, and remodelling phases, respectively. The inflammatory phase is key for successful tissue reconstruction and triggers the proliferative phase. The macrophages in the non-healing wounds remain in the inflammatory loop, but their phenotypes can be changed via interactions with nanofibre-based scaffolds mimicking the organisation of the native structural support of healthy tissues. However, the organisation of extracellular matrix (ECM) is highly complex, combining order and disorder, which makes it difficult to replicate. The possibility of predicting the desirable biomimetic geometry and chemistry of these nanofibre scaffolds would streamline the scaffold design process. Fifteen families of nanofibre scaffolds, electrospun from combinations of polyesters (polylactide, polyhydroxybutyrate), polysaccharides (polysucrose, carrageenan, cellulose), and polyester ether (polydioxanone) were investigated and analysed using machine learning (ML). The Random Forest model had the best performance (92.8%) in predicting inflammatory responses of macrophages on the nanoscaffolds using tumour necrosis factor-alpha as the output. CellProfiler proved to be an effective tool to process scanning electron microscopy (SEM) images of the macrophages on the scaffolds, successfully extracting various features and measurements related to cell phenotypes M0, M1, and M2. Deep learning modelling indicated that convolutional neural network models have the potential to be applied to SEM images to classify macrophage cells according to their phenotypes. The complex organisation of the nanofibre scaffolds can be analysed using graph theory (GT), revealing the underlying connectivity patterns of the nanofibres. Analysis of GT descriptors showed that the electrospun membranes closely mimic the connectivity patterns of the ECM. We conclude that ML-facilitated, GT-quantified engineering of cellular scaffolds has the potential to predict cell interactions, streamlining the pipeline for tissue engineering.

Lignin-cellulose complexes derived from agricultural wastes for combined antibacterial and tissue engineering scaffolds for cutaneous leishmaniasis wounds

Bacterial infections in wounds significantly impair the healing process. The use of natural antibacterial products over synthetic antibiotics has emerged as a new trend to address antimicrobial resistance. An ideal tissue engineering scaffold to treat infected wounds should possess antibacterial properties, while simultaneously promoting tissue regrowth. Synthesis of hydrogel scaffolds with antibacterial properties using hemp shive (HT1/HT2) lignin, sugarcane bagasse (SCB) lignin and cellulose was carried out. All lignin samples had low molecular weights and were constituted of G-type β-5 dimers, linked by β-O-4 bonds, as determined by MALDI-TOF-MS. Hemp lignin was more cytotoxic to mouse fibroblasts (L929) compared to SCB lignin. All lignin samples demonstrated antibacterial properties against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis, with greater efficiency against Gram-negative strains. 3D hydrogels were engineered by crosslinking SCB lignin with SCB cellulose in varying weight ratios in the presence of epichlorohydrin. The stiffness of the hydrogels could be tailored by varying the lignin concentration. All hydrogels were biocompatible; however, better fibroblast adhesion was observed on the blended hydrogels compared to the 100% cellulose hydrogel, with the cellulose : lignin 70 : 30 hydrogel showing the highest L929 proliferation and best antibacterial properties with a 24-hour bacterial growth reduction ranging from 30.8 to 57.3%.

From traditional medicine to nanomedicine: potential of Ginkgo biloba extracts in treating inflammatory skin diseases

The use of plant extracts as a potential cure for various conditions has moved from traditional medicine to evidence-based medicine. Skin diseases have been addressed since time immemorial using plant extracts through observational and traditional knowledge and passed on through generations. With the advent of modern techniques, the molecular mechanisms of action of plant extracts/isolates are being deciphered with more precision, and more nanomedicine-based therapies are being studied to improve their therapeutic efficacy and stability. The leaves and seeds of Ginkgo biloba (G. biloba), an ancient medicinal tree species, have been used in Chinese herbal medicine for thousands of years. G. biloba extracts have been widely studied as a neuroprotective and anti-ischaemic drug for ischaemia-reperfusion injuries in the heart, lungs, brain, kidneys, and other organs. However, the use of G. biloba can be accompanied with side effects and drug interactions. Although, there is now a growing interest for its use in skincare, the mechanisms of action of the extract are not fully understood and vital aspects of G. biloba, such as its neuroprotective and angiogenic properties contributing to the treatment of inflammatory skin diseases and skin ageing, are yet to be investigated. This review critically discusses the mechanisms of action of different constituents of G. biloba extracts linked to their potential interference in the molecular mechanisms underlying the pathogenesis of inflammatory skin diseases. In addition to its ability to act on oxidative stress, G. biloba can regulate angiogenesis through its compounds such as ginkgetin or ginkgolide K, which either inhibit aberrant angiogenesis in eczema/psoriasis or increase microcirculation during skin ageing. G. biloba may also contribute to the control of pruritus in atopic dermatitis via a neuroprotective and anti-inflammatory mechanism by suppressing JAK2/STAT3 signalling pathways. This review also highlights nanomedicine strategies to decrease the side effects and enhance the efficacy of the extracts. Similar strategies have been successfully used for anticancer molecules in targeted chemotherapy and iron delivery in anaemia treatment.