A Polysaccharide-based Hydrogel and PLGA Microspheres for Sustained P24 Peptide Delivery: An In vitro and In vivo Study Based on Osteogenic Capability

Recent Advances in Peptide-Loaded PLGA Nanocarriers for Drug Delivery and Regenerative Medicine

Peptide-loaded poly(lactide-co-glycolide) (PLGA) nanocarriers represent a transformative approach to addressing the challenges of peptide-based therapies. These systems offer solutions to peptide instability, enzymatic degradation, and limited bioavailability by providing controlled release, targeted delivery, and improved stability. The versatility of PLGA nanocarriers extends across therapeutic domains, including cancer therapy, neurodegenerative diseases, vaccine development, and regenerative medicine. Innovations in polymer chemistry, surface functionalization, and advanced manufacturing techniques, such as microfluidics and electrospraying, have further enhanced the efficacy and scalability of these systems. This review highlights the key physicochemical properties, preparation strategies, and proven benefits of peptide-loaded PLGA systems, emphasizing their role in sustained drug release, immune activation, and tissue regeneration. Despite remarkable progress, challenges such as production scalability, cost, and regulatory hurdles remain.

The Mechanism and Latest Research Progress of Blood-Brain Barrier Breakthrough

The bloodstream and the central nervous system (CNS) are separated by the blood-brain barrier (BBB), an intricate network of blood vessels. Its main role is to regulate the environment within the brain. The primary obstacle for drugs to enter the CNS is the low permeability of the BBB, presenting a significant hurdle in treating brain disorders. In recent years, significant advancements have been made in researching methods to breach the BBB. However, understanding how to penetrate the BBB is essential for researching drug delivery techniques. Therefore, this article reviews the methods and mechanisms for breaking through the BBB, as well as the current research progress on this mechanism.

The Impact of Nano-Hydroxyapatite Scaffold Enrichment on Bone Regeneration In Vivo-A Systematic Review

OBJECTIVES

In order to ensure improved and accelerated bone regeneration, nano-hydroxyapatite scaffolds are often enriched with different bioactive components to further accelerate and improve bone healing. In this review, we critically examined whether the enrichment of nHAp/polymer scaffolds with growth factors, hormones, polypeptides, microRNAs and exosomes improved new bone formation in vivo.

MATERIALS AND METHODS

Out of 2989 articles obtained from the literature search, 106 papers were read in full, and only 12 articles met the inclusion criteria for this review.

RESULTS

Several bioactive components were reported to stimulate accelerated bone regeneration in a variety of bone defect models, showing better results than bone grafting with nHAp scaffolds alone.

CONCLUSIONS

The results indicated that composite materials based on nHAp are excellent candidates as bone substitutes, while nHAp scaffold enrichment further accelerates bone regeneration. The standardization of animal models should be provided in order to clearly define the most significant parameters of in vivo studies. Only in this way can the adequate comparison of findings from different in vivo studies be possible, further advancing our knowledge on bone regeneration and enabling its translation to clinical settings.

Harnessing the Potential of PLGA Nanoparticles for Enhanced Bone Regeneration

Recently, nanotechnologies have become increasingly prominent in the field of bone tissue engineering (BTE), offering substantial potential to advance the field forward. These advancements manifest in two primary ways: the localized application of nanoengineered materials to enhance bone regeneration and their use as nanovehicles for delivering bioactive compounds. Despite significant progress in the development of bone substitutes over the past few decades, it is worth noting that the quest to identify the optimal biomaterial for bone regeneration remains a subject of intense debate. Ever since its initial discovery, poly(lactic-co-glycolic acid) (PLGA) has found widespread use in BTE due to its favorable biocompatibility and customizable biodegradability. This review provides an overview of contemporary advancements in the development of bone regeneration materials using PLGA polymers. The review covers some of the properties of PLGA, with a special focus on modifications of these properties towards bone regeneration. Furthermore, we delve into the techniques for synthesizing PLGA nanoparticles (NPs), the diverse forms in which these NPs can be fabricated, and the bioactive molecules that exhibit therapeutic potential for promoting bone regeneration. Additionally, we addressed some of the current concerns regarding the safety of PLGA NPs and PLGA-based products available on the market. Finally, we briefly discussed some of the current challenges and proposed some strategies to functionally enhance the fabrication of PLGA NPs towards BTE. We envisage that the utilization of PLGA NP holds significant potential as a potent tool in advancing therapies for intractable bone diseases.

Advancements and Applications of Injectable Hydrogel Composites in Biomedical Research and Therapy

Injectable hydrogels have gained popularity for their controlled release, targeted delivery, and enhanced mechanical properties. They hold promise in cardiac regeneration, joint diseases, postoperative analgesia, and ocular disorder treatment. Hydrogels enriched with nano-hydroxyapatite show potential in bone regeneration, addressing challenges of bone defects, osteoporosis, and tumor-associated regeneration. In wound management and cancer therapy, they enable controlled release, accelerated wound closure, and targeted drug delivery. Injectable hydrogels also find applications in ischemic brain injury, tissue regeneration, cardiovascular diseases, and personalized cancer immunotherapy. This manuscript highlights the versatility and potential of injectable hydrogel nanocomposites in biomedical research. Moreover, it includes a perspective section that explores future prospects, emphasizes interdisciplinary collaboration, and underscores the promising future potential of injectable hydrogel nanocomposites in biomedical research and applications.

A novel amelogenesis-inspired hydrogel composite for the remineralization of enamel non-cavitated lesions

Enamel non-cavitated lesions (NCLs) are subsurface enamel porosity from carious demineralization. The developed enamel cannot repair itself once NCLs occurs. The regeneration of mineral crystals in a biomimetic environment is an effective way to repair enamel subsurface defects. Previously, an amelogenin-derived peptide named QP5 was proven to repair demineralized enamel. In this work, inspired by amelogenesis, a novel biomimetic hydrogel composite containing the QP5 peptide and bioactive glass (BG) was designed, in which QP5 could promote enamel remineralization by guiding the calcium and phosphorus ions provided by BG. Also, BG could adjust the mineralization micro-environment to alkalinity, simulating the pH regulation of ameloblasts during enamel maturity. The BQ hydrogel composite showed biosafety and possessed capacity for enamel binding, ion release and pH buffering. Enamel NCLs treated with the BQ hydrogel composite showed a higher reduction in lesion depth and mineral loss both in vitro and in vivo. Moreover, compared to the hydrogels containing only BG or QP5, groups treated with the BQ hydrogel composite attained more surface microhardness recovery and color recovery, exhibiting resistance to erosion and abrasion of the remineralization layer. We envision that the BQ hydrogel composite can provide a biomimetic micro-environment to favor enamel remineralization, thus reducing the lesion depth and increasing the mineral content as a promising biomimetic material for enamel NCLs.

New insight into brain disease therapy: nanomedicines-crossing blood-brain barrier and extracellular space for drug delivery

INTRODUCTION

Brain diseases including brain tumor, Alzheimer's disease, Parkinson's disease, etc. are difficult to treat. The blood-brain barrier (BBB) is a major obstacle for drug delivery into the brain. Although nano-package and receptor-mediated delivery of nanomedicine markedly increases BBB penetration, it yet did not extensively improve clinical cure rate. Recently, brain extracellular space (ECS) and interstitial fluid (ISF) drainage in ECS have been found to determine whether a drug dissolved in ISF can reach its target cells. Notably, an increase in tortuosity of ECS associated with slower ISF drainage induced by the accumulated harmful substances, such as: amyloid-beta (Aβ), α-synuclein, and metabolic wastes, causes drug delivery failure.

AREAS COVERED

The methods of nano-package and receptor-mediated drug delivery and the penetration efficacy of nanomedicines across BBB and ECS are assessed.

EXPERT OPINION

Invasive delivering drug via ECS and noninvasive near-infrared photo-sensitive nanomedicines may provide a promising benefit to patients with brain disease.

Microsphere-Gel Composite System with Mesenchymal Stem Cell Recruitment, Antibacterial, and Immunomodulatory Properties Promote Bone Regeneration via Sequential Release of LL37 and W9 Peptides

Various types of biomaterials have been widely used to treat complex bone defects. However, potential infection risks and inappropriate host immune responses induced by biomaterials can adversely affect the final bone repair outcome. Therefore, the development of novel bone biomaterials with antibacterial and immunomodulatory capabilities is conducive to achieving a good interaction between the host and material, thereby creating a local microenvironment favorable for osteogenesis and ultimately accelerating bone regeneration. In this study, we fabricated a porcine small intestinal submucosa (SIS) hydrogel containing LL37 peptides and polylactic-glycolic acid (PLGA) microspheres encapsulated with WP9QY(W9) peptide (LL37-W9/PLGA-SIS), which can fill irregular bone defects and exhibits excellent mechanical properties. In vitro experiments showed that the microsphere-gel composite system had sequential drug release characteristics. The LL37 peptide released first had good antibacterial performance and BMSC recruitment ability, which could prevent infection at an early stage and increase the number of BMSCs at the injured site. In addition, it also has immunomodulatory properties, showing both pro-inflammatory and anti-inflammatory activities, but its early pro-inflammatory properties are more inclined to activate the M1 phenotype of macrophages. Moreover, the subsequently released W9 peptide not only reduced the expression of pro-inflammatory genes to alleviate inflammation and induced more macrophages to convert to M2 phenotypes but also promoted the osteogenic differentiation of BMSCs. This finely regulated immune response is considered to be more closely related to the physiological bone healing process. When studying the interaction between macrophages and BMSCs mediated by the material, it was found that the immunomodulatory and osteogenic effects were enhanced. In vivo experiments, we constructed rat skull defect models, which further proved that LL37-W9/PLGA-SIS gel can properly regulate the immune response, and has a good ability to promote osteogenesis in situ. In conclusion, the LL37-W9/PLGA-SIS hydrogel has great application prospects in immune regulation and bone therapy.

PLGA-based biodegradable microspheres in drug delivery: recent advances in research and application

Biodegradable microspheres have been widely used in the field of medicine due to their ability to deliver drug molecules of various properties through multiple pathways and their advantages of low dose and low side effects. Poly (lactic-co-glycolic acid) copolymer (PLGA) is one of the most widely used biodegradable material currently and has good biocompatibility. In application, PLGA with a specific monomer ratio (lactic acid and glycolic acid) can be selected according to the properties of drug molecules and the requirements of the drug release rate. PLGA-based biodegradable microspheres have been studied in the field of drug delivery, including the delivery of various anticancer drugs, protein or peptide drugs, bacterial or viral DNA, etc. This review describes the basic knowledge and current situation of PLGA biodegradable microspheres and discusses the selection of PLGA polymer materials. Then, the preparation methods of PLGA microspheres are introduced, including emulsification, microfluidic technology, electrospray, and spray drying. Finally, this review summarizes the application of PLGA microspheres in drug delivery and the treatment of pulmonary and ocular-related diseases.