Macromolecular bioscience最新文献

Thrombotic disorders rank among the principal global mortality factors. Despite significant advancements in interventional therapy technologies, conventional medical robots remain constrained by rigid architectures and elevated invasiveness, leading to vascular wall stress and frictional injury. Furthermore, these systems face challenges in reconciling the flexibility necessary for untethered navigation with reliable vascular traversal. To overcome these limitations, we present a magnetically actuated Micro-transformers (MAMT) with in situ structural reconfigurability. The microrobot, constructed from shape memory polymer (SMP), leverages the magnetothermal effect of Fe₃O₄ magnetic nanoparticles induced by an alternating magnetic field (AMF). When the temperature surpasses the glass transition temperature (50°C) of the SMP, the robot's structure transitions from its initial rod-like form to a final helical shape. Thus, dual-mode operation is achieved: rod-shaped structures for navigation and spiral-shaped structures for thrombus fragmentation. In the MAMT fabricated in this paper, in a simulated blood environment at room temperature, structural switching could be completed within 148 ± 8 s with AMF, and its shape recovery ratio could reach 92.11%. In the simulated thrombus clearance experiments, the thrombus clearance ratio could reach 52.7%. It can reduce the risk of vascular wall injury and enhance the safety of thrombus removal, offering an innovative solution for thrombus treatment.

Bioprinting technologies face challenges in designing bioinks that possess optimal pre- and post-bioprinting properties. In most cases, enhancing flowability to improve pre-bioprinting properties results in inferior mechanical properties of the post-printed constructs. To achieve adequate mechanical strength, physical or chemical cross-linking is used, which compromises the biocompatibility and degradability of the constructs. A xanthan gum (XG) and tamarind seed polysaccharide (TSP) blend bioink was developed to overcome these limitations. Amongst several ratios, 4XG:1TSP (4X1T) demonstrated the highest printability with accuracy >95%. Rheological investigations revealed shear thinning viscosity while the LVER and creep recovery for 4X1T (698 MPa, 97%) and 4X (624 MPa, 85%) showed suitable properties for bioprinting applications. FTIR indicated hydrogen-bonding interactions between XG and TSP, conferring structural stability to the post-printed constructs without any crosslinking agent. The constructs showed loss of microstructure after 21 days of incubation in phosphate buffer (pH 7.5) at 37°C. In vitro cytocompatibility studies with human-derived SH-SY5Y cells disclosed no significant difference between the viability of cells seeded on XG and 4X1T, or cells bioprinted with 4X1T bioinks. It is concluded that the XG-TSP blend provides a bioink with promising printability, mechanical integrity, degradability, and cytocompatibility for the fabrication of tissue engineering constructs.

Transdermal peptides, Engineered from bioactive peptides through rational sequence modification and structural optimization, transdermal peptides have emerged as a transformative strategy for enhancing the transdermal delivery of macromolecular drugs, proteins, and nucleic acids. This review outlines the structural classifications of bioactive peptides, including short, linear, cyclic, cationic, anionic, and neutral peptides, as well as their diverse biological sources. It focuses on the design principles and penetration mechanisms of transdermal peptides. These peptides interact dynamically with skin constituents, such as lipids and keratins, by fine-tuning the hydrophilic-hydrophobic balance, molecular weight, and conformational stability. This transiently disrupts the stratum corneum barrier and facilitates drug permeation via endocytosis and receptor-mediated pathways. They find applications in various pharmaceutical domains, including localized anticancer and antimicrobial therapies, as well as in cosmetics for whitening, anti-aging, and moisturizing. They are also being explored in innovative areas such as hair regeneration and wound healing. When combined with advanced delivery platforms, such as nanocarriers, microneedles, and microfluidic systems, transdermal peptides can significantly improve targeting efficacy and enable controlled release. Despite challenges related to peptide immunogenicity and scalable synthesis, the future integration of smart, stimuli-responsive technologies and artificial intelligence promises to Bioactive peptides, Skin permeation mechanisms, Skin transmission, Transdermal peptidesadvance personalized transdermal therapeutics.

Current treatments for critical-sized bone defects are often ineffective, necessitating advanced biomaterial scaffolds that can address this limitation. A key challenge in developing these scaffolds is achieving sustained, localized delivery of osteoinductive drugs, which is crucial for enhancing bone tissue regeneration within the defect site. This research engineered a novel κ-carrageenan-based composite scaffold incorporating hydroxyapatite-coated chitosan nanoparticles for regulated rosuvastatin release. Chitosan nanoparticles containing rosuvastatin were synthesized using a water-in-oil emulsion method and subsequently coated with hydroxyapatite. κ-carrageenan-based scaffolds were then fabricated with varying concentrations of nanoparticles (0%, 10%, 20%, and 30%) and evaluated for their physical and mechanical properties. They were also assessed for biocompatibility, osteogenic differentiation potential, and hemocompatibility. Notably, the hydroxyapatite coating increased the size of nanoparticles and enabled a stable, long-term release of rosuvastatin. Moreover, incorporating these nanoparticles into scaffolds further enhanced the sustained release profile appropriate for long-term bone healing. Scaffolds containing 20% nanoparticles demonstrated the highest mechanical strength and were selected for cell adhesion, proliferation, and differentiation studies. Alkaline phosphatase activity and alizarin red staining confirmed the scaffolds’ ability to promote osteogenic differentiation. Hemocompatibility assessment revealed a low hemolysis percentage (< 5%) for the carrageenan-based scaffolds, indicating good blood compatibility. Overall, the developed composite scaffold exhibits promising biocompatibility and efficacy for the controlled delivery of rosuvastatin and the repair of bone defects.

Polydeoxyribonucleotide (PDRN), a bioactive DNA fragment, has been known to promote anti-inflammatory responses and wound healing primarily via adenosine A₂A receptor activation. However, low molecular weight PDRN can undergo rapid degradation, limiting its sustained therapeutic efficacy. In this study, we developed a scalable method to produce high-purity, and low molecular weight PDRN (c.a. 325 bp) from calf thymus DNA via physical fragmentation. To enhance its stability and delivery, PDRN was encapsulated in poly(lactic-co-glycolic acid) (PLGA) to form PDRN/PLGA nanoparticles, yielding uniform and spherical particles (336 ± 43 nm). These nanoparticles exhibited excellent colloidal stability and biodegradability (38.3% over 14 days), with sustained PDRN release (88.39% over 14 days). Moreover, the nanoformulation effectively protected PDRN from thermal, acidic, enzymatic, and UV degradation. The PDRN/PLGA nanoparticles, which exhibited no cytotoxicity or hemolysis, demonstrated superior anti-inflammatory and wound-healing efficacy compared to free PDRN. In an in vitro lipopolysaccharide (LPS)-induced inflammatory wound model, they significantly accelerated wound closure compared to both LPS-treated and untreated controls. These results suggest that nanoformulation effectively protects low molecular weight PDRN, thereby significantly enhancing its therapeutic activity and underscore the potential of PDRN/PLGA nanoparticles as a stable and effective platform for the regeneration of skin inflammation.