Bioengineered liposome-scaffold composites as therapeutic delivery systems

Co-delivery of VEGF and amoxicillin using LP-coated co-axial electrospun fibres for the potential treatment of diabetic wounds

Diabetic complications present throughout a wide range of body tissues, however one of the most widely recognised complications remains to be chronic diabetic wounds. Current treatment options largely rely on standard wound treatment routines which provide no promotion of wound healing mechanisms at different physiological stages of repair. Recently materials produced using novel additive manufacturing techniques have been receiving attention for applications in wound care and tissue repair. Additive manufacturing techniques have recently been used in the interest of targeted drug delivery and production of novel materials resembling characteristics of native tissues. The potential to exploit these highly tailorable manufacturing techniques for the design of novel wound care remedies is highly desirable. In the present study two additive manufacturing techniques are combined to produce a scaffold for the treatment of diabetic wounds. The combination of microfluidic manufacturing of an antimicrobial liposome (LP) formulation and a coaxial electrospinning method incorporating both antimicrobial and proangiogenic factors allowed dual delivery of therapeutics to target both infection and lack of vascularisation at wound sites. The coaxial fibres comprised of a polyvinyl alcohol (PVA) core containing vascular endothelial growth factor (VEGF) and a poly (l-lactide-co-ε-caprolactone) (PLCL) shell blended with amoxicillin (Amox). Additionally, a liposomal formulation was produced to incorporate Amox and adhered to the surface of fibres loaded with Amox and VEGF. The liposomal loading provided the potential to deliver a much higher, more clinically relevant dose of Amox without detrimentally changing the mechanical properties of the material. The growth factor release was sustained up to 7-days in vitro. The therapeutic effect of the antibiotic loading was analysed using a disk diffusion method with a significant increase in zone diameter following LP adhesion, proving the full scaffold system had improved efficacy against both Gram-positive and Gram-negative strains. Additionally, the dual-loaded scaffolds show enhanced potential for supporting vascular growth in vitro, as demonstrated via a viability assay and tubule formation studies. Results showed a significant increase in the average total number of tubes from 10 in control samples to 77 in samples fully-loaded with Amox and VEGF.

Combinational System of Lipid-Based Nanocarriers and Biodegradable Polymers for Wound Healing: An Updated Review

Skin wounds have imposed serious socioeconomic burdens on healthcare providers and patients. There are just more than 25,000 burn injury-related deaths reported each year. Conventional treatments do not often allow the re-establishment of the function of affected regions and structures, resulting in dehydration and wound infections. Many nanocarriers, such as lipid-based systems or biobased and biodegradable polymers and their associated platforms, are favorable in wound healing due to their ability to promote cell adhesion and migration, thus improving wound healing and reducing scarring. Hence, many researchers have focused on developing new wound dressings based on such compounds with desirable effects. However, when applied in wound healing, some problems occur, such as the high cost of public health, novel treatments emphasizing reduced healthcare costs, and increasing quality of treatment outcomes. The integrated hybrid systems of lipid-based nanocarriers (LNCs) and polymer-based systems can be promising as the solution for the above problems in the wound healing process. Furthermore, novel drug delivery systems showed more effective release of therapeutic agents, suitable mimicking of the physiological environment, and improvement in the function of the single system. This review highlights recent advances in lipid-based systems and the role of lipid-based carriers and biodegradable polymers in wound healing.

Astragalus Polysaccharides/PVA Nanofiber Membranes Containing Astragaloside IV-Loaded Liposomes and Their Potential Use for Wound Healing

Delayed wound healing is a common and serious complication in diabetic patients, especially the slow healing of foot ulcers, which seriously affects the quality of life of patients and is also the most important risk factor for lower limb amputation. The multifunctional novel dressing prepared by loading the polymer nanofibers with anti-inflammatory and prohealing plant extracts can promote the wound repair of these ulcers by electrospinning technology. Liposomes are nanoparticles prepared from phospholipids and have been widely used as drug delivery systems. Liposomes can be combined with electrospun nanofibrous webs to facilitate local and sustained delivery of loaded bioactive substances. In this study, liposomes were prepared with astragaloside IV (AS) by employing a modified ethanol injection method and conducting the physical and chemical characterization (e.g., the particle size, polydispersity index, zeta potential, and entrapment efficiency). Astragalus polysaccharides were extracted from Astragalus membranaceus. Subsequently, we prepared the electrospun polyvinyl alcohol (PVA)/astragalus polysaccharide (APS)/astragaloside IV (AS) nanofibers. The morphology of the produced ASL/APS/PVA, APS/PVA, and PVA nanofibers were analyzed by scanning electron microscopy (SEM), and it turns out that the addition of astragalus extract made the fiber diameter smaller and the fibers arranged neatly with no dripping. An induced diabetic rat model was built, and a diabetic ulcer model was built by total cortical resection to assess the prorepair ability of the prepared nanofibers. According to in vivo animal experiments, the nanofibrous membrane loaded with APS and ASL was reported to inhibit the occurrence of wound inflammation, enhance the deposition of collagen fibers (P < 0.05) and the repair of regenerated epithelium (P < 0.05), and effectively strengthen the wound healing of diabetic rats (P < 0.05). In brief, PVA-loaded APS/ASL nanofibrous membranes refer to a prominent wound healing dressing material, which can effectively facilitate the healing of diabetic wounds, and they are demonstrated to be highly promising for application in diabetic wound dressings and tissue engineering.

Nanoarmour-shielded single-cell factory for bacteriotherapy of Parkinson's disease

Cell-based therapy for Parkinson's disease (PD) is a novel and promising approach in recent years. However, exogenous cells are easy to be captured and destroyed by the harsh environment in vivo, so their application prospects have been severely limited. Here, a facile yet versatile approach for decorating individual living cells with nano-armor coatings is reported. By simply self-assembly with liposome under a cyto-compatible condition, the lipid bimolecular coating on the surface of each cell acts as armor to effectively protect it from the attack and destruction of strong acids and digestive enzymes during the oral treatment of PD. Our results demonstrated that the liposome coated B. adolescentis (LCB) could significantly improve the colonization rate in the intestinal tract. LCB, as a living cell factory, can self-regulate to produce a constant concentration of γ-aminobutyric acid and maintain a longer half-life for the treatment of PD. Then, we also explored the specific mechanism of LCB to improve the behavior of murine models of PD, including abating inflammatory effects, reducing neuronal apoptosis, regulating the activity of dopaminergic neurons and microglia. The simple nano-armor shielded single-cell factory can produce neurotransmitters-like drugs on demand in vivo, introducing novel strategies of integration of producing and using to the research of drug delivery field.

A Comprehensive Review on the Applications of Exosomes and Liposomes in Regenerative Medicine and Tissue Engineering

Tissue engineering and regenerative medicine are generally concerned with reconstructing cells, tissues, or organs to restore typical biological characteristics. Liposomes are round vesicles with a hydrophilic center and bilayers of amphiphiles which are the most influential family of nanomedicine. Liposomes have extensive research, engineering, and medicine uses, particularly in a drug delivery system, genes, and vaccines for treatments. Exosomes are extracellular vesicles (EVs) that carry various biomolecular cargos such as miRNA, mRNA, DNA, and proteins. As exosomal cargo changes with adjustments in parent cells and position, research of exosomal cargo constituents provides a rare chance for sicknesses prognosis and care. Exosomes have a more substantial degree of bioactivity and immunogenicity than liposomes as they are distinctly chiefly formed by cells, which improves their steadiness in the bloodstream, and enhances their absorption potential and medicinal effectiveness in vitro and in vivo. In this review, the crucial challenges of exosome and liposome science and their functions in disease improvement and therapeutic applications in tissue engineering and regenerative medicine strategies are prominently highlighted.

Role of Liposomes-Based Stem Cell for Multimodal Cancer Therapy

The utilization of stem cells as novel carriers to target tissues or organs of interest is a challenging task in delivery system. The composite cellular delivery with diverse signalling molecules as therapeutics increases stem cell capability and possesses the promising potential to augment, modify or commence localized or systemic restoration for vital applications in regenerative medicine. The inherent potential of stem cells to immigrate and reside at wounded site facilitates transportation of genes, polypeptides or nanosized molecules. Liposomes are micro- to nano-lipidic vesicles formed in aqueous solutions to encapsulate complex hydrophilic and lipophilic chemical substances. Moreover, these novel nanocarriers provide safer and efficient delivery of bioactives together with their potential applications in vaccine production, cosmeceuticals, imaging and diagnostic purpose. Tissue engineering promotes rejuvenation process and involves the synchronized utilization of cells with 3D bio-material scaffolds to fabricate living structures. This strategy requires regulated stimulus of cultured cells through combined mechanical signals and bioactive agents. This review highlights and summarizes the mechanism involved in stem cell migration, strategies to enhance homing, safety and efficacy studies of stem cells in various disease models and discusses the potential role of liposomes in prolonged and localized delivery of bioactives for regenerative medicines and tissue engineering techniques. Graphical Abstract Role of PEGylated liposomes in cancer stem cell therapy.

Lipid-based nanosystems for targeting bone implant-associated infections: current approaches and future endeavors

Bone infections caused by Staphylococcus aureus are a major concern in medical care, particularly when associated with orthopedic-implant devices. The ability of the bacteria to form biofilms and their capacity to invade and persist within osteoblasts turn the infection eradication into a huge challenge. The reduction of antibiotic penetration through bacterial biofilms associated with the presence of persistent cells, ability to survive in the host, and high tolerance to antibiotics are some of the reasons for the difficult treatment of these infections. Effective therapeutic approaches are urgently needed. In this sense, lipid-based nanosystems, such as liposomes, have been investigated as an innovative and alternative strategy for the treatment of implant-associated S. aureus infections, due to their preferential accumulation at infected sites and interaction with S. aureus. This review highlights the recent advances on antibiotic-loaded liposome formulations both in vitro and in vivo and how the interaction with S. aureus biofilms may be improved by modulating the liposomal external surface. Graphical Abstract.

A 3D Macroporous Alginate Graphene Scaffold with an Extremely Slow Release of a Loaded Cargo for In Situ Long-Term Activation of Dendritic Cells

Ex vivo manipulation of autologous antigen-presenting cells and their subsequent infusion back into the patient to dictate immune response is one of the promising strategies in cancer immunotherapy. Here, a 3D alginate scaffold embedded with reduced graphene oxide (rGO) is proposed as a vaccine delivery platform for in situ long-term activation of antigen-presenting dendritic cells (DCs). High surface area and hydrophobic surface of the rGO component of the scaffold provide high loading and a very slow release of a loaded antigen, danger signal, and/or chemoattractant from the scaffold. This approach offers long-term bioavailability of the loaded cargo inside the scaffold for manipulation of recruited DCs. After mice are subcutaneously vaccinated with the macroporous alginate graphene scaffold (MAGS) loaded with ovalbumin (OVA) and granulocyte-macrophage colony-stimulating factor (GM-CSF), this scaffold recruits a significantly high number of DCs, which present antigenic information via major histocompatibility complex class I for a long period. Furthermore, an MAGS loaded with OVA, GM-CSF, and CpG promotes production of activated T cells and memory T cells, leading to the suppression of OVA-expressing B16 melanoma tumor growth in a prophylactic vaccination experiment. This study indicates that an MAGS can be a strong candidate for long-term programming and modulating immune cells in vivo.