ACS Applied Bio Materials最新文献

Objective: To identify factors affecting condylar bone changes following surgical-orthodontic treatment.

Methods: A total of 200 patients with dentofacial deformities were classified into skeletal Classes I, II, and skeletal Class III groups consisting of 61 and 139 subjects, respectively. Temporomandibular joints (TMJs) were evaluated using clinical findings and computed tomography images before treatment, immediately before surgery, and 6 months after surgery.

Results: Condylar bone changes occurred at a significantly higher rate after surgery in both groups. Factors related to condylar bone changes following surgical-orthodontic treatment included skeletal Class I or II, disc displacement, and condylar bone changes before treatment. There were three cases with condylar bone changes after surgery that were diagnosed with condylar resorption and skeletal Class II and anterior disc displacement before surgery.

Conclusion: Condylar resorption could occur when the load on the condyle increases after orthognathic surgery and exceeds the permissible limit.

Mineralized collagen fibrils are the building blocks of bone, and the mineralization of collagen fibrils is generally regulated by noncollagenous proteins (NCPs). However, the functions of NCPs are difficult to investigate in vivo. Here, we use poly(acrylic acid) (PAA) with different molecular weights (5, 50, 450, and 4000 kDa) as analogs of NCPs and explore their effects on collagen mineralization in vitro. All the PAA molecules can promote the intrafibrillar mineralization of calcium carbonate (CaCO₃) following these steps: the precursors infiltrate the gap zones of collagen, and transform into organized calcite nanocrystals within collagen. An increase in molecular weight significantly accelerates the mineralization rate of collagen films, approximately 0.67 μm min^-1 at 4000 kDa, four times that of 5 kDa (0.16 μm min^-1). However, the generation of contractile stress via intrafibrillar mineralization in tendons exhibits a contrary tendency. It reaches 24.2 MPa at 5 kDa, much higher than that of 4000 kDa (8.3 MPa), due to rapid mineralization causing severe extrafibrillar precipitation around the tendon. The controllable mineralization of collagen matrices may inspire the development of bone repair and regeneration in the future.

Patients and healthcare systems face significant social and financial challenges due to the increasing number of individuals with chronic external and internal wounds that fail to heal. The complexity of the healing process remains a serious health concern, despite the effectiveness of conventional wound dressings in promoting healing. Recent advancements in materials science and fabrication techniques have led to the development of innovative dressings that enhance wound healing. To further expedite the healing process, novel approaches such as nanoparticles, 3D-printed wound dressings, and biomolecule-infused dressings have emerged, along with cell-based methods. Additionally, gene therapy technologies are being harnessed to generate stem cell derivatives that are more functional, selective, and responsive than their natural counterparts. This review highlights the significant potential of biomaterials, nanoparticles, 3D bioprinting, and gene- and cell-based therapies in wound healing. However, it also underscores the necessity for further research to address the existing challenges and integrate these strategies into standard clinical practice.

In today's world, where stress and addiction are increasingly prevalent due to job pressures and coping mechanisms, dopamine (Dopa), a key hormone linked to mood, happiness, and mental health, has become vital for understanding conditions like depression and anxiety. Our study focuses on detecting Dopa pathways both in vitro using HEK293 cells and in vivo using zebrafish under stress and addiction conditions. We employed a biocompatible organic fluorophore (P1), with pyrazole-4-carboxaldehyde as the recognition unit, which demonstrated a detection limit of 8.2 nM, aligning with physiological Dopa levels. P1's efficacy in detecting Dopa was validated in human samples (urine, blood, and serum) and artificial samples, confirming its potential for real-world applications. This research is crucial for developing better diagnostic tools and therapies for dopamine-related disorders, offering significant societal benefits for addressing mental health challenges.

Piezoelectricity is reported to be able to promote bone scaffolds with excellent osteogenic performance. Herein, barium titanate/β-tricalcium phosphate (BTO/β-TCP) piezoelectric composite scaffolds were 3D printed, and their osteogenic performances were investigated in detail. The fabrication of BTO/β-TCP piezoelectric composite scaffolds employed cutting-edge DLP 3D printing technology. The scaffolds, featuring a triply periodic minimal surface (TPMS) design with a porosity of 60%, offered a unique structural framework. A comprehensive assessment of the composition, piezoelectric properties, and mechanical characteristics of the BTO/β-TCP scaffolds was conducted. Notably, an increase in the BTO volume fraction from 50 to 80 vol % within the scaffolds led to a reduction in compressive strength, decreasing from 2.47 to 1.74 MPa. However, this variation was accompanied by a substantial enhancement in the piezoelectric constant d₃₃, soaring from 1.4 pC/N to 21.6 pC/N. Utilizing mouse osteoblasts (MC3T3-E1) in a live/dead cell staining assay, under the influence of external ultrasound, demonstrated the commendable biocompatibility of these piezoelectric composite ceramic bone scaffolds. Furthermore, thorough analyses of alkaline phosphatase (ALP) activity and polymerase chain reaction (PCR) findings provided compelling evidence of the scaffolds' superior osteogenic properties, underpinning their effectiveness at the cellular protein and gene levels. In conclusion, this study offers a groundbreaking strategy for the employment of BTO/β-TCP piezoelectric composite scaffolds in bone implant applications, harnessing their unique blend of biocompatibility, piezoelectricity, and osteogenic potential.

During the wound healing process, complications such as bacterial attachment or inflammation may occur, potentially leading to surgical site infections. To reduce this risk, many commercial sutures contain biocides such as triclosan; however, this chemical has been linked to toxicity and contributes to the occurrence of bacterial resistance. In response to the need for more biocompatible alternatives, we here present an approach inspired by the innate human defense system: utilizing mucin glycoproteins derived from porcine mucus to create more cytocompatible suture coatings with antibiofouling properties. By attaching manually purified mucin to commercially available sutures through a simple and rapid coating process, we obtain sutures with cell-repellent and antibacterial properties toward Gram-positive bacteria. Importantly, our approach preserves the very good mechanical and tribological properties of the sutures while offering options for further modifications: the mucin matrix can either be condensed for controlled localized drug release or covalently functionalized with inorganic nanoparticles for hard tissue applications, which allows for tailoring a commercial suture for specific biomedical use cases.

Bacterial microcompartments (BMCs) are self-assembling protein shell structures that are widely investigated across a broad range of biological and abiotic chemistry applications. A central challenge in BMC research is the targeted capture of enzymes during shell assembly. While crystallography and cryo-EM techniques have been successful in determining BMC shell structures, there has been only limited success in visualizing the location of BMC-captured enzyme cargo. Here, we demonstrate the opportunity to use small-angle X-ray scattering (SAXS) and pair distance distribution function (PDDF) measurements combined with quantitative comparison to coordinate structure models as an approach to characterize BMC shell structures in solution conditions directly relevant to biochemical function. Using this approach, we analyzed BMC shells from Haliangium ochraceum (HO) that were isolated following expression in E. coli. The analysis allowed the BMC shell structures and the extent of encapsulated enzyme cargo to be identified. Notably, the results demonstrate that HO-BMC shells adventitiously capture significant amounts of cytoplasmic cargo during assembly in E. coli. Our findings highlight the utility of SAXS/PDDF analysis for evaluating BMC architectures and enzyme encapsulation, offering valuable insights for designing BMC shells as platforms for biological and abiotic catalyst capture within confined environments.

Wound management has made significant advances over the past few decades, particularly with the development of advanced dressings that facilitate autolytic debridement, the absorption of wound exudate, and protection from external bacteria. However, finding a single dressing that effectively addresses all four phases of wound healing─hemostasis, inflammation, proliferation, and remodeling─remains a major challenge. Additionally, biofilms in chronic wounds pose a substantial obstacle by shielding microbes from topical antiseptics and antibiotics, thereby delaying the healing process. This study evaluates the wound-healing properties of a commercially available bioactive microfiber gelling (BMG) dressing made from chitosan alongside commercially available silver-loaded carboxymethyl cellulose (CMC-Ag) dressing, carboxymethyl cellulose dressing (CMC) and cotton gauze. In vitro testing demonstrated that the BMG dressing significantly exhibited superior fluid absorption and exudate-locking properties compared with the CMC-Ag dressing. Additionally, the BMG dressing effectively sequestered and eradicated wound-relevant pathogenic microorganisms, including drug-resistant bacteria. Its bioactive properties were further highlighted by its ability to enhance platelet-derived growth factor (PDGF) expression and sequester matrix metalloproteases (MMPs). Overall, this study highlights the effectiveness of the BMG dressing in wound management, particularly in exudate absorption and antimicrobial activity, demonstrating its relevance in wound care.

Surgical reattachment of tendon to bone is the standard therapy for rotator cuff tear (RCT), but its effectiveness is compromised by retear rates of up to 94%, primarily due to challenges in achieving successful tendon-bone enthesis regeneration under natural conditions. Biological augmentation using biomaterials has emerged as a promising approach to address this challenge. In this study, a bilayer construct incorporates polydopamine (PDA)-mediated bone morphogenetic protein 2 (BMP2) and BMP12 in separate poly(lactic-co-glycolic acid) (PLGA) fiber layers to promote osteoblast and tenocyte growth, respectively, and intermediate fibrocartilage formation, aiming to enhance the regenerative potential of tendon-bone interfaces. The lower layer, consisting of PLGA fibers with BMP2 immobilization through PDA adsorption, significantly accelerated osteoblast growth. Concurrently, the upper BMP12@PLGA-PDA fiber mat facilitated fibrocartilage formation and tendon tissue regeneration, evidenced by significantly elevated tenocyte viability and tenogenic differentiation markers. Therapeutic efficacy assessed through in vivo RCT models demonstrated that the dual-BMP construct augmentation significantly promoted the healing of tendon-bone interfaces, confirmed by biomechanical testing, cartilage immunohistochemistry analysis, and collagen I/II immunohistochemistry analysis. Overall, this combinational strategy, which combines augmentation patches with the controlled release of dual growth factors, shows great promise in improving the overall success rates of rotator cuff repairs.

Recreating the structural and mechanical properties of native tissues in vitro presents significant challenges, particularly in mimicking the dense fibrillar network of extracellular matrixes such as skin and tendons. This study develops a reversible collagen film through cycling collagen self-assembly and disassembly, offering an innovative approach to address these challenges. We first generated an engineered collagen scaffold by applying plastic compression to the collagen hydrogel. The reversibility of the collagen assembly was explored by treating the scaffold with lactic acid, leading to its breakdown into an amorphous gel─a process termed defibrillogenesis. Subsequent immersion of this gel in phosphate buffer facilitated the reassembly of collagen into fibrils larger than those in the original scaffold yet with the D-banding pattern characteristic of collagen fibrils. Transfer learning of the mobileNetV2 convolutional neural network trained on atomic force microscope images of collagen nanoscale D-banding patterns was created with 99% training and testing accuracy. In addition, extensive external validation was performed, and the model achieved high robustness and generalization with unseen data sets. Further innovation was introduced by applying collagen hybridizing peptides, which significantly accelerated and directed the assembly of collagen fibrils, promoting a more organized and aligned fibrillar structure. This study not only demonstrates the feasibility of creating a reversible collagen film that closely mimics the density and structural properties of the native matrix but also highlights the potential of using collagen hybridizing peptides to control and enhance collagen fibrillogenesis. Our findings offer promising tissue engineering and regenerative medicine strategies by enabling precise manipulation of collagen structures in vitro.