Monocryl suture, a new ultra-pliable absorbable monofilament suture

BMP2 peptide-modified polycaprolactone-collagen nanosheets for periodontal tissue regeneration

Introduction

Periodontitis leads to the degradation of tooth-supporting tissues, ultimately causing tooth mobility and loss. Guided tissue regeneration (GTR) surgery employs barrier membranes to facilitate tissue regeneration. However, conventional membranes lack bone-inducing properties, thereby limiting their efficacy. Our objective was to develop a bifunctional GTR membrane that combines mechanical stability with bone-inducing capabilities. To achieve this, we engineered BMP2 peptide-modified polycaprolactone-collagen nanosheets (BPCNs) to enhance periodontal regeneration by improving cell adhesion, osteogenesis, and anti-inflammatory activity.

Methods

BPCNs with nanoscale thickness were fabricated using the spin-coating technique, incorporating BMP2 peptides, collagen, polycaprolactone (PCL), and polyvinyl alcohol (PVA). Successful conjugation of BMP2 to the BPCNs was verified through UV spectrophotometry and confocal laser scanning microscopy. The biocompatibility and cell adhesion properties of BPCNs were rigorously assessed using CCK-8 assays, microscopic imaging, and quantitative cell counting. In vitro osteogenic efficacy was evaluated by Alizarin Red S (ARS) staining and quantitative reverse transcription polymerase chain reaction (qRT-PCR) to analyze osteogenic marker gene expression. A rat periodontal defect model was established to assess in vivo regenerative performance, with outcomes analyzed through micro-CT, hematoxylin-eosin (H&E) staining, and Masson's trichrome staining, confirming enhanced tissue regeneration and the absence of systemic toxicity. The mechanistic pathways underlying BPCNs-mediated regeneration were elucidated via RNA sequencing (RNA-seq), revealing the activation of osteogenic signaling cascades and the suppression of proinflammatory pathways.

Results

BPCNs demonstrated excellent biocompatibility, promoted fibroblast and bone marrow stem cell (BMSC) adhesion, and enhanced BMSC osteogenesis. Furthermore, BPCNs significantly promoted periodontal tissue regeneration in a rat model. Mechanistically, RNA-seq analysis revealed that BPCNs upregulated genes involved in tissue regeneration and downregulated proinflammatory pathways.

Discussion

This study introduced a novel osteoinductive nanosheet, termed BPCNs, which provides a groundbreaking material-based approach for the regenerative repair of periodontal tissue defects. These findings position BPCNs as a highly promising candidate for GTR surgery, with significant potential to improve clinical outcomes in periodontal regenerative medicine.

An Additive-Fabricated Biphasic Scaffold for Procedurally Promoting Bone Regeneration via Antioxidant and Osteogenesis

The repair process of bone tissue includes the early inflammatory response period and the late tissue repair period. It has been widely approved to be beneficial to the repair of bone injury by procedurally inhibiting the inflammatory response in the early stage and promoting bone regeneration in the late stage. In this study, the nano-hydroxyapatite/Poly(glycolide-co-caprolactone) (n-HA/PGCL) scaffold loaded with icariin was fabricated by fused deposition modeling technique, and the quercetin-loaded GelMA was further filled into the scaffold pores via light-curing methods to form a biphasic scaffold loaded with dual molecules (PHI + GQ scaffold). The releases of icariin and quercetin were sequential due to different degradation rates of GelMA and PGCL. In vitro, the scaffold not only scavenged reactive oxygen species production, but also promoted osteogenic differentiation of the MC-3T3-E1 cells. Furthermore, in vivo bone reconstruction of PHI + GQ scaffold was better than other groups by assessment of micro-CT data. In addition, the immunofluorescence staining of Arg-1 and iNOS indicated that PHI + GQ scaffold created an immune microenvironment conducive to bone repair due to the release of quercetin in the early stage, and HE and Masson staining suggested that PHI + GQ scaffold induced more new bone formation. These results demonstrated that the biphasic scaffold loaded with icariin and quercetin had both antioxidants in the early stage and osteogenesis properties in the late stage, obtaining satisfactory bone repair outcomes. Thus, the biphasic scaffold loaded with icariin and quercetin for sequential release could provide a promising solution for the restoration of bone defects and represent a potential strategy for bone regeneration.

Navigating the combinations of platelet-rich fibrin with biomaterials used in maxillofacial surgery

Platelet-rich fibrin (PRF) is a protein matrix with growth factors and immune cells extracted from venous blood via centrifugation. Previous studies proved it a beneficial biomaterial for bone and soft tissue regeneration in dental surgeries. Researchers have combined PRF with a wide range of biomaterials for composite preparation as it is biocompatible and easily acquirable. The results of the studies are difficult to compare due to varied research methods and the fact that researchers focus more on the PRF preparation protocol and less on the interaction of PRF with the chosen material. Here, the literature from 2013 to 2024 is reviewed to help surgeons and researchers navigate the field of commonly used biomaterials in maxillofacial surgeries (calcium phosphate bone grafts, polymers, metal nanoparticles, and novel composites) and their combinations with PRF. The aim is to help the readers select a composite that suits their planned research or medical case. Overall, PRF combined with bone graft materials shows potential for enhancing bone regeneration both in vivo and in vitro. Still, results vary across studies, necessitating standardized protocols and extensive clinical trials. Overviewed methods showed that the biological and mechanical properties of the PRF and material composites can be altered depending on the PRF preparation and incorporation process.

Tailoring biomaterials for skin anti-aging

Skin aging is the phenomenon of degenerative changes in the structure and function of skin tissues over time and is manifested by a gradual loss of skin elasticity and firmness, an increased number of wrinkles, and hyperpigmentation. Skin anti-aging refers to a reduction in the skin aging phenomenon through medical cosmetic technologies. In recent years, new biomaterials have been continuously developed for improving the appearance of the skin through mechanical tissue filling, regulating collagen synthesis and degradation, inhibiting pigmentation, and repairing the skin barrier. This review summarizes the mechanisms associated with skin aging, describes the biomaterials that are commonly used in medical aesthetics and their possible modes of action, and discusses the application strategies of biomaterials in this area. Moreover, the synergistic effects of such biomaterials and other active ingredients, such as stem cells, exosomes, growth factors, and antioxidants, on tissue regeneration and anti-aging are evaluated. Finally, the possible challenges and development prospects of biomaterials in the field of anti-aging are discussed, and novel ideas for future innovations in this area are summarized.

Moldable Plastics (Polycaprolactone) can be Acutely Toxic to Developing Zebrafish and Activate Nuclear Receptors in Mammalian Cells

Popularized on social media, hand-moldable plastics are formed by consumers into tools, trinkets, and dental prosthetics. Despite the anticipated dermal and oral contact, manufacturers share little information with consumers about these materials, which are typically sold as microplastic-sized resin pellets. Inherent to their function, moldable plastics pose a risk of dermal and oral exposure to unknown leachable substances. We analyzed 12 moldable plastics advertised for modeling and dental applications and determined them to be polycaprolactone (PCL) or thermoplastic polyurethane (TPU). The bioactivities of the most popular brands advertised for modeling applications of each type of polymer were evaluated using a zebrafish embryo bioassay. While water-borne exposure to the TPU pellets did not affect the targeted developmental end points at any concentration tested, the PCL pellets were acutely toxic above 1 pellet/mL. The aqueous leachates of the PCL pellets demonstrated similar toxicity. Methanolic extracts from the PCL pellets were assayed for their bioactivity using the Attagene FACTORIAL platform. Of the 69 measured end points, the extracts activated nuclear receptors and transcription factors for xenobiotic metabolism (pregnane X receptor, PXR), lipid metabolism (peroxisome proliferator-activated receptor γ, PPARγ), and oxidative stress (nuclear factor erythroid 2-related factor 2, NRF2). By nontargeted high-resolution comprehensive two-dimensional gas chromatography (GC × GC-HRT), we tentatively identified several compounds in the methanolic extracts, including PCL oligomers, a phenolic antioxidant, and residues of suspected antihydrolysis and cross-linking additives. In a follow-up zebrafish embryo bioassay, because of its stated high purity, biomedical grade PCL was tested to mitigate any confounding effects due to chemical additives in the PCL pellets; it elicited comparable acute toxicity. From these orthogonal and complementary experiments, we suggest that the toxicity was due to oligomers and nanoplastics released from the PCL rather than chemical additives. These results challenge the perceived and assumed inertness of plastics and highlight their multiple sources of toxicity.

Antimicrobial-coated sutures versus non-coated sutures in reducing surgical site infection: an updated systematic review and meta-analysis

BACKGROUND

Antimicrobial-coated sutures are one of the strategies to avoid surgical site infection (SSI) caused by microbial colonization on the surface of surgical sutures.

AIM

To investigate the effectiveness of antimicrobial-coated sutures in reducing SSI and develop the latest systematic evaluation evidence for clinical SSI prevention and the use of antimicrobial-coated sutures.

METHODS

The databases of MEDLINE, Embase, CINAHL, Cochrane, African Index Medicus, and WHO Global Health were searched from October 10th, 1990 to March 3rd, 2023 with language restricted to English, Spanish, and French. Meta-analysis was used to evaluate the impact of antimicrobial-coated sutures on SSI and whether their effectiveness is influenced by the type of sutures or wounds. Subgroup analyses were conducted based on type of sutures and wounds. Finally, quality of the retrieved evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

FINDINGS

Twenty-six randomized control trials (RCTs) and nine observational studies (OBSs) met the inclusion criteria. Antimicrobial sutures significantly reduced SSI risk (RCTs: odds ratio: 0.74; 95% confidence interval: 0.63-0.87; P = 0.0002; OBSs: OR: 0.61; 95% CI: 0.48-0.76; P < 0.0001). Only subgroup analysis of Polydioxanone Suture (PDS) Plus vs PDS, Vicryl Plus vs Vicryl and mixed wounds revealed consistent results in favour of antimicrobial-coated sutures. According to GRADE, the quality of RCT evidence is moderate, while that of OBS evidence is low.

CONCLUSION

Antimicrobial-coated sutures are effective in reducing the risk of postoperative SSI among a large number of surgical patients. However, the available evidence is of moderate/low quality and many studies had conflicts of interest.

Advances and Techniques in Subcuticular Suturing for Abdominal Wall Closure: A Comprehensive Review

Subcuticular suturing has emerged as a prominent technique for abdominal wall closure, offering notable benefits in cosmetic outcomes, infection reduction, and patient satisfaction. This comprehensive review delves into the evolution and current state of subcuticular suturing, examining its principles, techniques, and advancements. Traditional methods like continuous and interrupted suturing are compared with modern innovations like barbed sutures and knotless techniques. Clinical outcomes, including healing efficacy, complication rates, and cost-effectiveness, are analyzed to highlight the technique's advantages. The review also explores specific applications in various surgical specialities, presenting case studies and clinical trials to substantiate its effectiveness. Despite certain challenges and limitations, the future of subcuticular suturing appears promising with ongoing research and technological advancements. This review aims to thoroughly understand subcuticular suturing, emphasizing its significance in improving surgical outcomes and patient care in abdominal wall closure.

Highly Elastic, Bioresorbable Polymeric Materials for Stretchable, Transient Electronic Systems

Substrates or encapsulants in soft and stretchable formats are key components for transient, bioresorbable electronic systems; however, elastomeric polymers with desired mechanical and biochemical properties are very limited compared to non-transient counterparts. Here, we introduce a bioresorbable elastomer, poly(glycolide-co-ε-caprolactone) (PGCL), that contains excellent material properties including high elongation-at-break (< 1300%), resilience and toughness, and tunable dissolution behaviors. Exploitation of PGCLs as polymer matrices, in combination with conducing polymers, yields stretchable, conductive composites for degradable interconnects, sensors, and actuators, which can reliably function under external strains. Integration of device components with wireless modules demonstrates elastic, transient electronic suture system with on-demand drug delivery for rapid recovery of post-surgical wounds in soft, time-dynamic tissues.

Enabling Proregenerative Medical Devices via Citrate-Based Biomaterials: Transitioning from Inert to Regenerative Biomaterials

Regenerative medicine aims to restore tissue and organ function without the use of prosthetics and permanent implants. However, achieving this goal has been elusive, and the field remains mostly an academic discipline with few products widely used in clinical practice. From a materials science perspective, barriers include the lack of proregenerative biomaterials, a complex regulatory process to demonstrate safety and efficacy, and user adoption challenges. Although biomaterials, particularly biodegradable polymers, can play a major role in regenerative medicine, their suboptimal mechanical and degradation properties often limit their use, and they do not support inherent biological processes that facilitate tissue regeneration. As of 2020, nine synthetic biodegradable polymers used in medical devices are cleared or approved for use in the United States of America. Despite the limitations in the design, production, and marketing of these devices, this small number of biodegradable polymers has dominated the resorbable medical device market for the past 50 years. This perspective will review the history and applications of biodegradable polymers used in medical devices, highlight the need and requirements for regenerative biomaterials, and discuss the path behind the recent successful introduction of citrate-based biomaterials for manufacturing innovative medical products aimed at improving the outcome of musculoskeletal surgeries.

Improvement of Endothelial Cell-Polycaprolactone Interaction through Surface Modification via Aminolysis, Hydrolysis, and a Combined Approach

Polycaprolactone (PCL) is a promising material for the fabrication of alternatives to autologous grafts used in coronary bypass surgery. PCL biodegrades over time, allowing cells to infiltrate the polymeric matrix, replacing the biodegrading graft, and creating a fully functional vessel constituted of autologous tissue. However, the high hydrophobicity of PCL is associated with poor cell affinity. Surface modification of PCL can increase this cell affinity, making PCL an improved scaffold material for acellular vascular grafts. In this study, the surface of PCL films was modified by hydrolysis, aminolysis, and the combination thereof to introduce carboxyl, hydroxyl, and amino groups on the surface. Only the hydrolyzed films exhibited a significant increase in their hydrophilicity, although further testing showed that all aminolysis conditions had amino groups on the surface. Furthermore, in vitro experiments with human umbilical endothelial cells (HUVECs) were performed to assess changes in cell affinity for PCL due to the surface treatments. PCL treated with sodium hydroxide (NaOH), a hydrolysis reaction, showed a significant increase in endothelial cell adhesion after 24 hours with a significant increase in cell survival after 72 hours. Thus, NaOH treatment improves the biocompatibility and endothelialization of PCL, creating a competent candidate for artificial, acellular, biodegradable vascular grafts.

Postoperative Mechanomodulation Decreases T-Junction Dehiscence After Reduction Mammaplasty: Early Scar Analysis From a Randomized Controlled Trial

BACKGROUND

Soft tissue and cutaneous tension is an important contributor to complicated wound healing and poor scar cosmesis after surgery and its mitigation is a key consideration in aesthetic and reconstructive procedures.

OBJECTIVES

The study objective was to assess the efficacy of the force modulating tissue bridge (FMTB) ("Brijjit", Brijjit Medical Inc., Atlanta, GA) in reducing mechanical tension on postoperative wounds.

METHODS

A prospective, single-center, randomized, within-subject clinical trial was conducted to evaluate wound healing and nascent scar formation after 8 weeks of postoperative wound support with the FMTB. Patients received standard of care (SOC) subcuticular closure on the vertical incision of 1 breast and experimental closure with the FMTB on the contralateral incision after Wise-pattern reduction mammaplasty. Three-dimensional wound analysis and rates of T-junction dehiscence were evaluated by clinical assessment at 2, 4, 6, and 8 weeks postsurgery.

RESULTS

Thirty-four patients (n = 68 breasts) completed 8 weeks of postoperative FMTB application. There was a reduced rate of T-junction wound dehiscence in FMTB breasts (n = 1) vs SOC breasts (n = 11) (P < .01). The mean vertical incision wound area during the intervention period was significantly decreased in the FMTB breast (1.5 cm2) vs the SOC breast (2.1 cm2) (P < .01) and was significantly lower at 2-, 4-, and 8-week follow-up (P < .01). Only the closure method was significantly associated with variations in Week 8 wound area (P < .01) after linear regression modeling.

CONCLUSIONS

FMTBs decrease nascent scar dimensions and reduce the occurrence of wound dehiscence. This study provides evidence that the use of continuous mechanomodulation significantly reduces postoperative wound complications after skin closure.

LEVEL OF EVIDENCE: 2

Alveolar Ridge Augmentation with a Novel Combination of 3D-Printed Scaffolds and Adipose-Derived Mesenchymal Stem Cells-A Pilot Study in Pigs

Alveolar ridge augmentation is an important dental procedure to increase the volume of bone tissue in the alveolar ridge before the installation of a dental implant. To meet the high demand for bone grafts for alveolar ridge augmentation and to overcome the limitations of autogenous bone, allografts, and xenografts, researchers are developing bone grafts from synthetic materials using novel fabrication techniques such as 3D printing. To improve the clinical performance of synthetic bone grafts, stem cells with osteogenic differentiation capability can be loaded into the grafts. In this pilot study, we propose a novel bone graft which combines a 3D-printed polycaprolactone-tricalcium phosphate (PCL-TCP) scaffold with adipose-derived mesenchymal stem cells (AD-MSCs) that can be harvested, processed and implanted within the alveolar ridge augmentation surgery. We evaluated the novel bone graft in a porcine lateral alveolar defect model. Radiographic analysis revealed that the addition of AD-MSCs to the PCL-TCP scaffold improved the bone volume in the defect from 18.6% to 28.7% after 3 months of healing. Histological analysis showed the presence of AD-MSCs in the PCL-TCP scaffold led to better formation of new bone and less likelihood of fibrous encapsulation of the scaffold. Our pilot study demonstrated that the loading of AD-MSCs improved the bone regeneration capability of PCL-TCP scaffolds, and our novel bone graft is suitable for alveolar ridge augmentation.

A Systematic Review on Polyester Scaffolds in Dental Three-dimensional Cell Printing: Transferring Art from the Laboratories to the Clinics

Objective

The purpose of this systematic review is to describe developments in three-dimensional (3D) cell printing in the formation of dental pulp tissue using polyester as a scaffold to revitalize the damaged dental pulp tissue.

Materials and methods

A literature search for all the data published in PubMed and Google Scholar from January 2000 to April 2022 was conducted. Articles with the keywords 3D cell printing, scaffolds, polyester, dental pulp, and dentistry were used. Inclusion criteria consisted of any publication in electronic or print media directly studying or commenting on the use of polyester scaffolds in 3D cell printing technology in the regeneration of dental pulp. A total of 528 articles were selected, of which 27 duplicates and 286 irrelevant articles were discarded. A total of 215 articles were finally included in the systematic review.

Result and conclusion

For dental pulp regeneration, several scaffolds have been discovered to be appealing. Polylactic acid (PLA), polyglycolic acid (PGA), and their copolymers are nontoxic and biocompatible synthetic polyesters that degrade by hydrolysis and have received Food and Drug Administration (FDA) approval for a variety of applications. This review paper is intended to spark new ideas for using a certain scaffold in a specific regenerative approach to produce the desired pulp-dentin complex.

A novel approach to evaluate the mechanical responses of elastin-like bioresorbable poly(glycolide-co-caprolactone) (PGCL) suture

Poly(glycolide-co-caprolactone) (PGCL) has become a novice to the bioresorbable suture owing to the synergistic properties taken from the homo-polyglycolide (PGA) and polycaprolactone (PCL) such as excellent bioresorption and flexibility. In addition to under conventional monotonic loading, the understanding of mechanical responses of PGCL copolymers under complex loading conditions such as cyclic and stress relaxation is crucial for its application as a surgical suture. Consequently, the present work focuses on evaluating the mechanical responses of PGCL sutures under monotonic, cyclic, and stress relaxation loading conditions. Under monotonic loading, the stress-strain behavior of the PGCL suture was found to be non-linear with noticeable strain-rate dependence. Under cyclic loading, inelastic responses including stress-softening, hysteresis and permanent set were observed. During cyclic loading, both stress-softening and hysteresis were found to increase with the maximum strain. In multi-step stress relaxation, the PGCL sutures were observed to exhibit a strong viscoelastic response. In an attempt to describe the relationship between the stress-relaxation and strain-induced crystallization (SIC) occurring during the loading and relaxation processes, a schematic illustration of the conformational change of polymer chains in PGCL sutures was proposed in this work. Results showed that SIC was dependent on the strain level as well as the loading and relaxation durations. The inelastic phenomena observed in PGCL sutures can be thus correlated to the combined effect of stress relaxation and SIC.

Recent Biomedical Applications of Coupling Nanocomposite Polymeric Materials Reinforced with Variable Carbon Nanofillers

The hybridization between polymers and carbon materials is one of the most recent and crucial study areas which abstracted more concern from scientists in the past few years. Polymers could be classified into two classes according to the source materials synthetic and natural. Synthetic polymeric materials have been applied over a floppy zone of industrial fields including the field of biomedicine. Carbon nanomaterials including (fullerene, carbon nanotubes, and graphene) classified as one of the most significant sources of hybrid materials. Nanocarbons are improving significantly mechanical properties of polymers in nanocomposites in addition to physical and chemical properties of the new materials. In all varieties of proposed bio-nanocomposites, a considerable improvement in the microbiological performance of the materials has been explored. Various polymeric materials and carbon-course nanofillers were present, along with antibacterial, antifungal, and anticancer products. This review spots the light on the types of synthetic polymers-based carbon materials and presented state-of-art examples on their application in the area of biomedicine.

Microfluidic preparation and optimization of sorafenib-loaded poly(ethylene glycol-block-caprolactone) nanoparticles for cancer therapy applications

The use of amphiphilic block copolymers to generate colloidal delivery systems for hydrophobic drugs has been the subject of extensive research, with several formulations reaching the clinical development stages. However, to generate particles of uniform size and morphology, with high encapsulation efficiency, yield and batch-to-batch reproducibility remains a challenge, and various microfluidic technologies have been explored to tackle these issues. Herein, we report the development and optimization of poly(ethylene glycol)-block-(ε-caprolactone) (PEG-b-PCL) nanoparticles for intravenous delivery of a model drug, sorafenib. We developed and optimized a glass capillary microfluidic nanoprecipitation process and studied systematically the effects of formulation and process parameters, including different purification techniques, on product quality and batch-to-batch variation. The optimized formulation delivered particles with a spherical morphology, small particle size (d_H < 80 nm), uniform size distribution (PDI < 0.2), and high drug loading degree (16 %) at 54 % encapsulation efficiency. Furthermore, the stability and in vitro drug release were evaluated, showing that sorafenib was released from the NPs in a sustained manner over several days. Overall, the study demonstrates a microfluidic approach to produce sorafenib-loaded PEG-b-PCL NPs and provides important insight into the effects of nanoprecipitation parameters and downstream processing on product quality.

Comparison of Absorbable and Nonabsorbable Sutures for Intradermal Skin Closure in Dogs

The study aimed to compare incisional wound healing with intradermal suture patterns performed with (a) absorbable suture with burying of the knots and (b) nonabsorbable suture anchored with clips. Ten dogs were included in the study. Surgically created skin incisions were apposed with continuous intradermal suture pattern with 4/0 poliglecaprone 25 with burying of the knots and continuous intradermal pattern with 4/0 polypropylene with clips. Cosmetic, clinical, ultrasonographic and histological scores were evaluated. The intradermal pattern with clips was easier to perform and required significantly less time to complete than the intradermal suture with burying of the knots. Cosmetic, clinical, ultrasonographic and histological evaluation scores did not differ significantly between the techniques. Irrespective of the technique used, the cosmetic, ultrasonographic, clinical and histological appearances of the incisions improved over time. In conclusion, polypropylene was found to be a safe and effective suture material for use with intradermal suture pattern with clips in dogs and to have an easy and quick application. However, in our sample, its earlier removal from wounds than poliglecaprone 25 was not found to be associated with a supposedly beneficial effect on wound healing and scar appearance. Both suture materials can be useful in intradermal suture techniques in dogs.

Wound Management following Total Knee Arthroplasty: An Updated Review

Optimal wound closure techniques following total knee arthroplasty (TKA) have focused on enhancing healing potential, preventing infection, yielding satisfactory cosmesis, and allowing early ambulation and functionality. An appropriate layered closure and management of the TKA typically involves addressing the (1) deep fascial layer; (2) subdermal layer; (3) intradermal layer, including the subcuticular region; and (4) final application of a specific aseptic dressing, each of which are covered here in detail. This focused critical review of the literature discusses traditional techniques used in all layers of wound closure following TKA while introducing several emerging popular techniques. For example, absorbable barbed skin sutures and occlusive dressings have the potential to reduce operative time, limit the need for early postoperative visits, obviate the need for suture or staple removal, and safely promote patient communication via telemedicine. As novel wound closure techniques continue to emerge and traditional approaches are improved upon, future comparative studies will assist in elucidating the key advantages of various options. In an extremely important field that has tremendous variability, these efforts may enable the reaching of a classically elusive standard of care for these techniques.

Feasibility and safety of inserting transient biodegradable stents in the pylorus during pylorus-preserving gastrectomy for gastric cancer: a preliminary study in a porcine for proof of concept

BACKGROUND

To evaluate whether insertion of self-biodegradable stent into the pylorus to prevent delayed-gastric emptying after pylorus-preserving gastrectomy is feasible and safe through porcine experiment.

METHODS

Self-biodegradable dumbbell-shaped pyloric stents were designed from absorbable suture materials: poly(glycolide-co-caprolactone) (PGCL) or poly-p-dioxanone (PPDO). After gastrotomy on ten pigs, each stent was inserted: two shams, four PGCL stents, and four PPDO stents. Body weight (Bwt), body temperature (BT), complete blood cell (CBC) count, and plain X-ray were evaluated. On postoperative day (POD) 13, euthanasia was performed for histologic evaluation.

RESULTS

Operation was successfully performed in all ten pigs. Without tagging suture, both stents migrated before POD 3. The migration was delayed up to POD 13, when the tagging sutures (-t) were applied between stent and stomach wall. Self-degradation of PGCL started from POD 3, and stents were completely excreted from the abdomen by POD 8. Although PPDO were also weakened as self-degradation progressed, its shape was maintained in gastrointestinal tract for 13 days. Unexpected sudden death occurred in the pig with PPDO-t2 on POD 10, which is more likely due to acute volvulus rather than stent-related complication. There was no significant difference between three groups in terms of Bwt, BT, CBC, and histology (sham vs. PGCL vs. PPDO, all p > 0.05).

CONCLUSION

The concept of biodegradable stents made of absorbent suture material seems feasible in porcine experiment. Among them, PGCL which has shown rapid absorption, appears to be a more suitable material for transient pyloric absorbable stent when considering safety aspect.

Objective Assessment of the Long-Term Volumizing Action of a Polycaprolactone-Based Filler

Background

The polycaprolactone-based filler, (PCL-1, Ellansé-S), forms part of the recently growing portfolio of biodegradable collagen-stimulating fillers. It is comprised of a suspension of 25-50 micron diameter microspheres of polycaprolactone (PCL) (30%) in a carboxymethyl cellulose (CMC) gel carrier (70%) and has gained popularity due to its long-term volumizing action.

Objective

This study outlines a retrospective case series of nine patients injected with the PCL-1, for volume augmentation in the mid-face. Objective volume calculations were performed with the Canfield Vectra 3D Imaging System at two time points post-implantation, with the objective of determining the longevity of the volumizing effect of the bio-stimulating substance.

Results

A clear increase in volume, between 50-150%, was found in all of the patients at two years, over and above the volume initially injected. All the patients were satisfied with the longevity of the results.

Discussion

The PCL-based filler is believed to afford immediate volume restoration due to the CMC gel component and a long-term action due to neo-collagenesis, induced by the PCL microspheres. The CMC gel is known to dissipate within 6-8 weeks, only to be replaced by new collagen induced by the PCL particles. Thus soft-tissue formation induced by the PCL particles, ultimately leads to a sustained volumizing effect.

Conclusion

The PCL-based filler is shown to have a sustained volumizing effects of at least 2 years duration with clear evidence of increase in volume over and above the volume injected, in all of the cases studied. This is indicative of significant neo-collagenesis induced by the PCL microspheres.

Physicochemical and biological properties of nanohydroxyapatite grafted with star-shaped poly(ε-caprolactone)

To overcome the disadvantages generated by the lack of interfacial bonding between hydroxyapatite nanocrystals (HAPN) and agglomeration of particles in the development of biodegradable nanocomposites a chemical grafting method was applied to modify the surface of HAPN through grafting of the three-arms star-shaped poly(ε-caprolactone) (SPCL) onto the nanoparticles. The chemical grafting of SPCL onto HAPN (SPCL-g-HAPN) has been investigated using Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy (TEM), photoelectron spectroscopy, X-ray diffraction, zeta potential (ZP) and contact angle (CA). TEM micrographs of the SPCL-g-HAPN revealed the existence of hybrid organic/inorganic (O/I) nanoscale domains. The results of albumin (HSA) and fibrinogen (HFb) adsorption indicate resistance to HFb adsorption by SPCL-g-HAPN relatively to unmodified HAPN. The ZP and CA measurement suggest a heterogeneous topology for SPCL-g-HAPN likely due to the existence of hydrophobic-hydrophilic regions on the nanocomposite surface. The enzyme degradation by cholesterol esterase and lipase indicates that the rates of hydrolysis for SPCL-g-HAPN were very slow relative to the SPCL/HAPN blends. The in vitro biological studies showed that the human osteoblast-like cells (MG-63) cells had normal morphology and they were able to attach and spread out on SPCL-g-HAPN surfaces. A higher overall cellular proliferation was observed on SPCL-g-HAPN scaffolds compared to pure HAPN or SPCL materials.

Is Iatrogenic Implant Contamination Preventable Using a 16-Step No-Touch Protocol?

BACKGROUND

Intraoperative contamination of the surgical field during aesthetic breast augmentation may lead to implant infection with devastating consequences. This study covers a period of 30 years and is divided into 2 phases: a retrospective phase from 1992-2004 when a standard approach was used and a prospective phase from 2004-2022 when a no-touch approach was implemented to avoid contamination.

METHODS

Patients in the standard and no-touch groups underwent aesthetic breast augmentation by the same senior surgeon (FDP) in the same outpatient surgical facility during the 30-year period of the study. Patients are divided into 2 groups: from 1992-2004 and from the implementation of the no-touch protocol in 2004-2022.

RESULTS

Patients who underwent breast augmentation using the no-touch approach developed no infections, whereas the standard group had an infection rate of 3.54% (P = .017). The validity of this finding is discussed.

CONCLUSIONS

The no-touch approach as described in this article was effective in reducing implant infection rate when performing aesthetic breast augmentation by 1 surgeon at 1 surgical center during an 18-year observation period. Multicenter prospective cooperative studies are necessary to validate perioperative iatrogenic contamination as the cause of implant infection and to explore optimal approaches that could eliminate implant contamination.

Crystallization Behavior and Morphology of Biodegradable Poly(ε-caprolactone)/Reduced Graphene Oxide Scaffolds

Morphology, thermal properties and the non-isothermal melt crystallization kinetics of biodegradable poly(ε-caprolactone) (PCL)/reduced graphene oxide (rGO) scaffolds are studied with differential scanning calorimetry (DSC) at various cooling rates (5, 10, 15 and 20 °C/min). Thermally induced phase separation was used to manufacture the scaffolds (TIPS). The micrographs show a more homogeneous and defined morphology with larger pores and thicker pore walls. The melting temperature (Tm), melting enthalpy (ΔHm), crystallization enthalpy (ΔHc) and degree of crystallinity (Xc) increased with the addition of rGO, suggesting larger and more perfect crystalline structures. The degree of crystallinity increased with the presence of rGO. The crystallization peak shifted to higher temperatures as the rGO concentration increased independently of the cooling rates. The peak shifted to lower temperatures as the cooling rate increased with the same rGO composition. The values of t1/2 (time needed to reach 50% crystallization) were lower for scaffolds with rGO. The values of the crystallization rate coefficient were higher when the porous support contained rGO, which indicates that their crystallization systems are faster. The activation energy obtained with the Kissinger method decreased with the presence of rGO. The results indicate that reduced graphene oxide acts as a nucleating agent in the non-isothermal melt crystallization process. The addition of small quantities of rGO changes their thermal properties with which they can be modified for application in the field of tissue engineering.

Mapping knowledge structure and themes trends of biodegradable Mg-based alloy for orthopedic application: A comprehensive bibliometric analysis

Background: Since Lambotte and Payr first studied Mg-based alloys for orthopedics in 1900, the research of this field has finally ushered in vigorous development in the 21st century. From the perspective of quantitative analysis, this paper clearly demonstrated the global research trend from 2005 to 2021 by using bibliometrics and scientometric analysis.

Methods: We obtained the publications from the Web of Science Core Collection (WoSCC) database. The bibliometric and scientometric analysis was conducted by using R software, CiteSpace software, VOSviewer software, Pajek software and Microsoft Excel program.

Results: In total, 1921 publications were retrieved. It can be found that the number of publications is gradually increasing year by year. We can find that the most prolific countrie, institution and researcher are China, Chinese Academy of Sciences and Zheng Yufeng, respectively. The most influential journals in this field are Acta Biomaterialia and Biomaterials, with 16,511 and 12,314 total citations, respectively. By conducting the co-cited documents-based clustering analysis, 16 research hotspots and their representative studies have been identified. Besides, by conducting analysis of keywords, we divided the keyword citation bursts representing the development of the field into three stages.

Conclusion: The number of researches on the biodegradable Mg-based alloys increased sharply all over the world in the 21st century. China has made significant progress in biodegradable Mg-based alloy research. More focus will be placed on osteogenic differentiation, fabrication, graphene oxide, antibacterial property, bioactive glass and nanocomposite, which may be the next popular topics in the field.

Polymeric Nanotechnologies for the Treatment of Periodontitis: A Chronological Review

Periodontitis is a chronic infectious and inflammatory disease of periodontal tissues estimated to affect 70 - 80 % of all adults. At the same time, periodontium, the site of periodontal pathologies, is an extraordinarily complex plexus of soft and hard tissues, the regeneration of which using even the most advanced forms of tissue engineering continues to be a challenge. Nanotechnologies, meanwhile, have provided exquisite tools for producing biomaterials and pharmaceutical formulations capable of elevating the efficacies of standard pharmacotherapies and surgical approaches to whole new levels. A bibliographic analysis provided here demonstrates a continuously increasing research output of studies on the use of nanotechnologies in the management of periodontal disease, even when they are normalized to the total output of studies on periodontitis. The great majority of biomaterials used to tackle periodontitis, including those that pioneered this interesting field, have been polymeric. In this article, a chronological review of polymeric nanotechnologies for the treatment of periodontitis is provided, focusing on the major conceptual innovations since the late 1990s, when the first nanostructures for the treatment of periodontal diseases were fabricated. In the opening sections, the etiology and pathogenesis of periodontitis and the anatomical and histological characteristics of the periodontium are being described, along with the general clinical manifestations of the disease and the standard means of its therapy. The most prospective chemistries in the design of polymers for these applications are also elaborated. It is concluded that the amount of innovation in this field is on the rise, despite the fact that most studies are focused on the refinement of already established paradigms in tissue engineering rather than on the development of revolutionary new concepts.

Medical Adhesives and Their Role in Laparoscopic Surgery—A Review of Literature

Laparoscopic surgery is undergoing rapid development. Replacing the traditional method of joining cut tissues with sutures or staples could greatly simplify and speed up laparoscopic procedures. This alternative could undoubtedly be adhesives. For decades, scientists have been working on a material to bond tissues together to create the best possible conditions for tissue regeneration. The results of research on tissue adhesives achieved over the past years show comparable treatment effects to traditional methods. Tissue adhesives are a good alternative to surgical sutures in wound closure. This article is a review of the most important groups of tissue adhesives including their properties and possible applications. Recent reports on the development of biological adhesives are also discussed.

Characterization of a Temporary Peripheral Nerve Stimulation Electrode Utilizing a Bioabsorbable Suture Substrate

Electrical stimulation after peripheral nerve injury (PNI) has the potential to promote more rapid and complete recovery of damaged fiber tracts. While permanently implanted devices are commonly used to treat chronic or persistent conditions, they are not ideal solutions for transient medical therapies due to high costs, increased risk of surgical injury, irritation, infection, and persistent inflammation at the site of the implant. Furthermore, removal of temporary leads placed on or around peripheral nerves may have unacceptable risk for nerve injury, which is counterproductive in developing therapies for PNI treatment. Transient devices which provide effective clinical stimulation while being capable of harmless bioabsorption may overcome key challenges in these areas. However, current bioabsorbable devices are limited in their robustness and require complex fabrication strategies and novel materials which may complicate their clinical translation pathway. In this study, we present a simple bioabsorbable / biodegradable electrode fabricated by modifying standard absorbable sutures, and we present data characterizing our prototype's stability in vitro and in vivo.

A Porcine Model Using Adipose Stem Cell-Loaded Scaffolds for Alveolar Ridge Augmentation

Tooth loss greatly affects a person's quality of life and many turn to dental implants to replace lost teeth. The success of a dental implant depends on the amount of alveolar bone supporting the implant, and thus, bone augmentation is often necessary to preserve or build up bone volume in the alveolar ridge. Bone can be augmented with autogenous bone, allografts, or xenografts, but the limitations of such natural bone grafts prompt researchers to develop synthetic scaffolds supplemented with cells and/or bioactive agents as alternative bone grafts. The translation of these combination scaffolds from the laboratory to the clinic requires reliable experimental models that can simulate the clinical conditions in human patients. In this article, we describe the use of a porcine alveolar defect model as a platform to evaluate the efficacy of a novel combination of a three-dimensional-printed polycaprolactone-tricalcium phosphate (PCL-TCP) scaffold and adipose-derived mesenchymal stem cells (AD-MSCs) in lateral alveolar augmentation. The surgical protocol for the defect creation and regenerative surgery, as well as analytical methods to determine the extent of tissue regeneration, are described and discussed.

Electrospun Medical Sutures for Wound Healing: A Review

With the increasing demand for wound healing around the world, the level of medical equipment is also increasing, but sutures are still the preferred medical equipment for medical personnel to solve wound closures. Compared with the traditional sutures, the nanofiber sutures produced by combining the preparation technology of drug-eluting sutures have greatly improved both mechanical properties and biological properties. Electrospinning technology has attracted more attention as one of the most convenient and simple methods for preparing functional nanofibers and the related sutures. This review firstly discusses the structural classification of sutures and the performance analysis affecting the manufacture and use of sutures, followed by the discussion and classification of electrospinning technology, and then summarizes the relevant research on absorbable and non-absorbable sutures. Finally, several common polymers and biologically active substances used in creating sutures are concluded, the related applications of sutures are discussed, and the future prospects of electrospinning sutures are suggested.

Clinical Evaluation of Intraoral Suture Patterns Using Poliglecaprone 25 in Greyhound Dogs

To evaluate healing and complications of extraction sites closed with a simple interrupted pattern (SI) and a simple continuous (SC) suture pattern in a prospective randomized clinical trial. Greyhounds were selected from a rescue with a standardized environment and naturally occurring disease. Surgical extractions were performed (35 sites) and all mucogingival flaps were closed with 4-0 poliglecaprone 25 using either SI or SC randomly assigned by surgical site. Oral healing/dehiscence, suture inflammation, suture loss, accumulation of debris, presence/nature of discharge, necrotic tissue and adjacent contact ulceration were evaluated. Fisher's exact test was used to compare categorical data and two-tail T tests used to compare continuous data. Results showed SC was faster to apply. No new dehiscence events were detected after Recheck 1. There was no significant difference for dehiscence scores between SI and SC. A trend was seen towards more major dehiscence in the SI group. This study concluded SC is an alternative to SI for closure of occlusal surfaces in the mouth. Mandibular canine tooth extraction sites were more likely to have a high dehiscence score than all other sites combined regardless of surgical technique.

Biodegradation of poly(L-lactic acid) and poly(ε-caprolactone) patches by human amniotic fluid in an in-vitro simulated fetal environment

Open spina bifida or myelomeningocele (MMC) is a devastating neurologic congenital defect characterized by primary failure of neural tube closure of the spinal column during the embryologic period. Cerebrospinal fluid leak caused by the MMC spinal defect in the developing fetus can result in a constellation of encephalic anomalies that include hindbrain herniation and hydrocephalus. The exposure of extruded spinal cord to amniotic fluid also poses a significant risk for inducing partial or complete paralysis of the body parts beneath the spinal aperture by progressive spinal cord damage in-utero. A randomized trial demonstrated that prenatal repair by fetal surgery, sometimes using patches, to cover the exposed spinal cord with a watertight barrier is effective in reducing the postnatal neurologic morbidity as evidenced by decreased incidence and severity of postnatal hydrocephalus and the reduced need for ventricular-peritoneal shunting. Currently, the use of inert or collagen-based patches are associated with high costs and inadequate structural properties. Specifically, the inert patches do not degrade after implantation, causing the need for a post-natal removal surgery associated with trauma for the newborn. Our present study is aimed towards in-vitro degradation studies of a newly designed patch, which potentially can serve as a superior alternative to existing patches for MMC repair. This novel patch was fabricated by blending poly(l-lactic acid) and poly(ε-caprolactone). The 16-week degradation study in amniotic fluid was focused on tracking changes in crystallinity and mechanical properties. An additional set of designed patches was exposed to phosphate-buffered saline (PBS), as a time-paired control. Crystallinity studies indicate the progress of hydrolytic degradation of the patch in both media, with a preference to bulk erosion in phosphate buffered saline and surface erosion in amniotic fluid. Mechanical testing results establish that patch integrity is not compromised up to 16 weeks of exposure either to body fluids analog (PBS) or to amniotic fluid.

Development of Neuronal Guidance Fibers for Stimulating Electrodes: Basic Construction and Delivery of a Growth Factor

State-of-the-art treatment for sensorineural hearing loss is based on electrical stimulation of residual spiral ganglion neurons (SGNs) with cochlear implants (CIs). Due to the anatomical gap between the electrode contacts of the CI and the residual afferent fibers of the SGNs, spatial spreading of the stimulation signal hampers focused neuronal stimulation. Also, the efficiency of a CI is limited because SGNs degenerate over time due to loss of trophic support. A promising option to close the anatomical gap is to install fibers as artificial nerve guidance structures on the surface of the implant and install on these fibers drug delivery systems releasing neuroprotective agents. Here, we describe the first steps in this direction. In the present study, suture yarns made of biodegradable polymers (polyglycolide/poly-ε-caprolactone) serve as the basic fiber material. In addition to the unmodified fiber, also fibers modified with amine groups were employed. Cell culture investigations with NIH 3T3 fibroblasts attested good cytocompatibility to both types of fibers. The fibers were then coated with the extracellular matrix component heparan sulfate (HS) as a biomimetic of the extracellular matrix. HS is known to bind, stabilize, modulate, and sustainably release growth factors. Here, we loaded the HS-carrying fibers with the brain-derived neurotrophic factor (BDNF) which is known to act neuroprotectively. Release of this neurotrophic factor from the fibers was followed over a period of 110 days. Cell culture investigations with spiral ganglion cells, using the supernatants from the release studies, showed that the BDNF delivered from the fibers drastically increased the survival rate of SGNs in vitro. Thus, biodegradable polymer fibers with attached HS and loaded with BDNF are suitable for the protection and support of SGNs. Moreover, they present a promising base material for the further development towards a future neuronal guiding scaffold.

Safety and feasibility assessment of biodegradable poly (l-lactic acid/ε-caprolactone) membrane for guided bone regeneration: A case series of first-in-human pilot study

Background/purpose

Guided bone regeneration (GBR) is the most popular technique for alveolar ridge augmentation in implant dentistry, and resorbable cell barrier membrane, made of collagen, is widely used. We tried to develop a new resorbable cell barrier membrane from an animal-free product. This study aimed to investigate the safety and feasibility for clinical application of poly (l-lactic acid/ε-caprolactone) [P (LA/CL)] membrane, a novel biodegradable synthetic material used for GBR.

Materials and methods

Patients who required horizontal bone augmentation (≥3 mm implant exposure) for implant treatment were included in the study. P (LA/CL) membrane was used simultaneously with implant placement to achieve bone augmentation by GBR. The occurrence of adverse events was assessed until the follow-up period of a second surgical procedure. The amount of bone augmentation was assessed by means of cone-beam computed tomography, and implant stability was assessed by measuring the implant stability quotient (ISQ). Student's t-test was used and the level of significance was set at p < 0.05.

Results

This first-in-human study comprised five participants. Adverse events were observed in three of five patients, and a cause-and-effect relationship of the membrane could not be denied in one of them. Good bone formation was observed in the GBR region of all five patients. The ISQ during the second surgical procedure indicated good osseointegration in all the patients.

Conclusion

The application of P (LA/CL) membrane for bone augmentation with GBR made it possible to maintain the augmented bone volume without causing any irreversible adverse events. However, further investigations on humans are required to confirm the safety of this biomaterial.

A Controlled Trial of Polyglytone 6211 versus Poliglecaprone 25 for Use in Intradermal Suturing in Dogs

Simple Summary

The choice of suture material for skin closure can affect the final cosmetic outcome, the risk of wound infection, and other complications in companion animals. We assessed two commercially available suture materials, namely Caprosyn and Monocryl, for use in suturing the skin of dogs, by using cosmetic, clinical, and histological evaluation. The results indicate only minimal differences between the two products, although better scores were achieved after using Monocryl. Both were found sufficient for use in intradermal suturing in dogs. The earlier absorption of Caprosyn, compared to Monocryl, did not have any additional beneficial effect on wound healing and scar appearance in dogs.

Abstract

The objective of this work was the comparative evaluation of the healing process after employing 4/0 poliglecaprone 25 and 4/0 polyglytone 6211 in a continuous intradermal suture pattern. Ten Beagle dogs were used, in which skin incisions were created surgically and subsequently were sutured by means of continuous intradermal pattern using polyglytone 6211 or poliglecaprone 25 suture. Cosmetic, clinical, and histologic scores were evaluated. The cosmetic appearance of the wounds was blindly evaluated on days 7, 14, 28, 180, 360, 730, and 1095. On the same days, tissue biopsy was performed for histological evaluation. Clinical evaluation was performed initially daily, then weekly, monthly, and finally yearly, till day 1095. The clinical appearance of the intradermal pattern with both sutures was initially very good, deteriorated in the second post-operative month and thereafter improved. The cosmetic, clinical, and histological differences between the two suture materials were minimal and statistically insignificant. Polyglytone 6211 is sufficient for use in intradermal suturing in dogs. However, its earlier absorption compared to poliglecaprone 25 did not have any beneficial effect on cutaneous wound healing and scar appearance in the experimental animals.

Aesthetic Nasal Lobule Correction Using a Three-Dimensional Printed Polycaprolactone Implant

ABSTRACT

Nasal tip plasty is a surgery that determines important rhinoplasty outcomes. A variety of autologous and alloplastic implants are utilized in this procedure, including 1 synthetic material known as polycaprolactone (PCL). This study provides background on the ready-made three-dimensional printed PCL implant for nasal lobule correction, before discussing the usefulness and effectiveness of the implant. A total of 23 patients who visited our hospital between January 2018 and January 2020 were evaluated in this study. We used 3 types of PCL implant to get an ideal shape for the nasal tip: tipball (globular shape), droneball (rugby ball shape), and dumbbell (dumbbell shape). The authors compared nasolabial angle and tip projection at the preoperative and postoperative period via photographic anthropometric analysis. In 4 patients, we also examined the dead space between the implant and soft tissue via ultrasonography. The follow-up period averaged 9.5 months and no serious complications were found after surgery. The nasolabial angle and tip projection had an average postoperative increase of 6.4° and 0.044, respectively. Ultrasonography revealed the attachment of the implant at the insertion site and no dead space was found. This is the first attempt to apply a ready-made three-dimensional printed PCL implant to a nasal lobule correction procedure. As the implant was easy to use and showed good results, it may be useful for aesthetic purposes in future nasal tip plasty procedures.

Hair Transplant Practice Guidelines

The field of hair transplant (HT) has grown exponentially in the past decade, especially after the introduction of follicular unit excision (FUE). There is much variation in criteria for case selection, the technique, pre- and post-procedure protocols, by different surgeons. Techniques continue to evolve and evidence in the form of controlled data is not available for all techniques and protocols being used; there is also a debate as to who can do what, what should be the training for staff, role of technicians. This has led to a situation wherein medico legal issues have cropped up as to what is minimum acceptable. An attempt is made to summarize standard protocols with the available evidence. It is emphasized that the objective of these guidelines is to recommend minimum standards for practice of hair transplantation. The principles outlined in these guidelines are of a general nature only, minimal in their level and are not meant to cover all situations. It should be understood that these recommendations are by no means binding and universal, represent minimum standards only and as in all surgical techniques, variations in techniques are possible. It is also further clarified that these are based on current literature, and as science evolves, these guidelines could also change in future. Where published evidence is not available, consensus expert opinion is presented. The task force emphasizes that each patient has to be treated on his/her own merit and that these guidelines do not limit the physician from making an appropriate choice or the necessary innovation for a given patient. The task force recognizes that the treating surgeon is best suited to decide what is needed for a given patient in a given situation. Innovations in medicine need flexibility in approach and these guidelines do not limit the surgeon from undertaking innovative research.

A Hemostatic Technique in Robot-Assisted Laparoscopic Partial Nephrectomy and Its Impact on Renal Function

Purpose

Robot-assisted partial nephrectomy (RAPN) has become popular in recent years for small renal masses. We describe a technique of suturing renal defects during RAPN that is reliable and quick, does not necessitate the need for hemostatic agents, and reduces perioperative complications.

Materials and methods

A total of 24 patients who underwent RAPN were included in the study period between 2013 and 2018 and data were analyzed. Perioperative and postoperative outcomes were measured and compared.

Results

The median tumor size was 4 cm. Median warm ischemia time was 41 minutes (IQR: 38-45 minutes) and estimated blood loss was 150 mL (IQR: 120-200 mL). There were no major intraoperative complications or conversions to open surgery. No urine leaks or postoperative bleedings were observed.

Conclusion

Our technique is safe and effective. It negates the use of hemostatic agents, decreases perioperative complications, and negates that determination of long-term renal function is not associated with prolonged warm ischemia time alone. Hence, we propose that our technique is safe in partial nephrectomy when the pelvic calyceal system and renal vessels are opened in multiple locations.

Functionalization of Polycaprolactone Electrospun Osteoplastic Scaffolds with Fluorapatite and Hydroxyapatite Nanoparticles: Biocompatibility Comparison of Human Versus Mouse Mesenchymal Stem Cells

A capability for effective tissue reparation is a living requirement for all multicellular organisms. Bone exits as a precisely orchestrated balance of bioactivities of bone forming osteoblasts and bone resorbing osteoclasts. The main feature of osteoblasts is their capability to produce massive extracellular matrix enriched with calcium phosphate minerals. Hydroxyapatite and its composites represent the most common form of bone mineral providing mechanical strength and significant osteoinductive properties. Herein, hydroxyapatite and fluorapatite functionalized composite scaffolds based on electrospun polycaprolactone have been successfully fabricated. Physicochemical properties, biocompatibility and osteoinductivity of generated matrices have been validated. Both the hydroxyapatite and fluorapatite containing polycaprolactone composite scaffolds demonstrated good biocompatibility towards mesenchymal stem cells. Moreover, the presence of both hydroxyapatite and fluorapatite nanoparticles increased scaffolds' wettability. Furthermore, incorporation of fluorapatite nanoparticles enhanced the ability of the composite scaffolds to interact and support the mesenchymal stem cells attachment to their surfaces as compared to hydroxyapatite enriched composite scaffolds. The study of osteoinductive properties showed the capacity of fluorapatite and hydroxyapatite containing composite scaffolds to potentiate the stimulation of early stages of mesenchymal stem cells' osteoblast differentiation. Therefore, polycaprolactone based composite scaffolds functionalized with fluorapatite nanoparticles generates a promising platform for future bone tissue engineering applications.

A Tuneable, Photocurable, Poly(Caprolactone)-Based Resin for Tissue Engineering-Synthesis, Characterisation and Use in Stereolithography

Stereolithography is a useful additive manufacturing technique for the production of scaffolds for tissue engineering. Here we present a tuneable, easy-to-manufacture, photocurable resin for use in stereolithography, based on the widely used biomaterial, poly(caprolactone) (PCL). PCL triol was methacrylated to varying degrees and mixed with photoinitiator to produce a photocurable prepolymer resin, which cured under UV light to produce a cytocompatible material. This study demonstrates that poly(caprolactone) methacrylate (PCLMA) can be produced with a range of mechanical properties and degradation rates. By increasing the degree of methacrylation (DM) of the prepolymer, the Young's modulus of the crosslinked PCLMA could be varied from 0.12-3.51 MPa. The accelerated degradation rate was also reduced from complete degradation in 17 days to non-significant degradation in 21 days. The additive manufacturing capabilities of the resin were demonstrated by the production of a variety of different 3D structures using micro-stereolithography. Here, β-carotene was used as a novel, cytocompatible photoabsorber and enabled the production of complex geometries by giving control over cure depth. The PCLMA presented here offers an attractive, tuneable biomaterial for the production of tissue engineering scaffolds for a wide range of applications.

Thermo-Rheological and Shape Memory Properties of Block and Random Copolymers of Lactide and ε-Caprolactone

Biodegradable block and random copolymers have attracted numerous research interests in different areas, due to their capability to provide a broad range of properties. In this paper, an efficient strategy has been reported for preparing biodegradable PCL-PLA copolymers with improved thermal, mechanical and rheological properties. Two block-copolymers are synthesized by sequential addition of the cyclic esters lactide (L-LA or D,L-LA) and ε-caprolactone (CL) in presence of a dimethyl(salicylaldiminato)aluminium compound. The random copolymer of L-LA and CL was synthetized by using the same catalyst. Chain structure, molar mass, thermal, rheological and mechanical properties are characterized by NMR, SEC, TGA, DSC, Rheometry and DMTA. Experimental results show that by changing the stereochemistry and monomer distribution of the copolymers it is possible to obtain a variety of properties. Promising shape-memory properties are also observed in the di-block copolymers characterized by the co-crystallization of CL and L-LA segments. These materials show great potential to substitute oil-based polymers for packaging, electronics, and medicine applications.

A predictive micromechanically-based model for damage and permanent deformations in copolymer sutures

An effective description of the mechanical behavior of biodegradable copolymers suture threads requires the analysis of their response under cyclic loading and the prediction of the fundamental damage and residual stretches effects. In this paper we propose a micromechanically-based model adopting a new form of Worm Like Chain free energy for the copolymer chains, which takes care of the insurgence of residual stretches on the basis of a rigorous statistical mechanics result. Under the affinity hypothesis we subsequently derive the macroscopic response of the material. The obtained model has a clear physical interpretation and depends on a small number of parameters, which can be fitted by a simple uniaxial test. The effectiveness of the theoretical results has then been verified by performing cyclic tests on Monocryl® monofilament sutures and showing the ability of the model in predicting with high accuracy the history dependence, the damage and permanent deformations in the obtained response.

Skin and subcutaneous fascia closure at caesarean section to reduce wound complications: the closure randomised trial

BACKGROUND

Wound infection is a common complication following caesarean section. Factors influencing the risk of infection may include the suture material for skin closure, and closure of the subcutaneous fascia. We assessed the effect of skin closure with absorbable versus non-absorbable suture, and closure versus non-closure of the subcutaneous fascia on risk of wound infection following Caesarean section.

METHODS

Women undergoing caesarean birth at an Adelaide maternity hospital were eligible for recruitment to a randomised trial using a 2 × 2 factorial design. Women were randomised to either closure or non-closure of the subcutaneous fascia and to subcuticular skin closure with an absorbable or non-absorbable suture. Participants were randomised to each of the two interventions into one of 4 possible groups: Group 1 - non-absorbable skin suture and non-closure of the subcutaneous fascia; Group 2 - absorbable skin suture and non-closure of the subcutaneous fascia; Group 3 - non-absorbable skin suture and closure of the subcutaneous fascia; and Group 4 - absorbable skin suture and closure of the subcutaneous fascia. The primary outcomes were reported wound infection and wound haematoma or seroma within the first 30 days after birth.

RESULTS

A total of 851 women were recruited and randomised, with 849 women included in the analyses (Group 1: 216 women; Group 2: 212 women; Group 3: 212 women; Group 4: 211 women). In women who underwent fascia closure, there was a statistically significant increase in risk of wound infection within 30 days post-operatively for those who had skin closure with an absorbable suture (Group 4), compared with women who had skin closure with a non-absorbable suture (Group 3) (adjusted RR 2.17; 95% CI 1.05, 4.45; p = 0.035). There was no significant difference in risk of wound infection for absorbable vs non-absorbable sutures in women who did not undergo fascia closure.

CONCLUSION

The combination of subcutaneous fascia closure and skin closure with an absorbable suture may be associated with an increased risk of reported wound infection after caesarean section.

TRIAL REGISTRATION

Prospectively registered with the Australian and New Zealand Clinical Trials Registry, number ACTRN12608000143325 , on the 20th March, 2008.

HuBiogel incorporated fibro-porous hybrid nanomatrix graft for vascular tissue interfaces

Native extracellular matrix (ECM) possesses the biochemical cues to promote cell survival. However, decellularized, the ECM loses its cell supporting mechanical integrity. We report, here, a novel biohybrid vascular graft of polycaprolactone (PCL), poliglecaprone (PGC) incorporated with human biomatrix as functional materials for vascular tissue interfacing by electrospinning, thus harnessing the biochemical cues from the ECM and the mechanical integrity of the polymer blends. The fabricated fibro-porous tubular small diameter graft (i.d. = 4 mm) from polymer blend was coated with a cocktail of collagenous matrix derived from human placenta called HuBiogel™. The compositional, morphological, and mechanical properties of graft were measured and compared with a non-coated tubular PCL/PGC graft using Fourier Transform infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). BCA assay was used to calculate the protein content and coating-uniformity throughout the hybrid graft. Mechanical properties such as tensile strength (1.6 MPa), Young's modulus (2.4 MPa), burst pressure (>1900 mmHg), and suture retention strength (2.3 N) of hybrid graft were found to be comparable to native blood vessels. Protein coating has improved the hydrophilicity and the biocompatibility (cell viability and cell-attachment) enhanced with human umbilical vein endothelial cells (HUVECs) seeded in vitro onto the lumen layer of the graft over two weeks. The overall results promise this new biohybrid graft to be a potential candidate for vascular tissue interface and regeneration.

Pre-Seeding of Simple Electrospun Scaffolds with a Combination of Endothelial Cells and Fibroblasts Strongly Promotes Angiogenesis

BACKGROUND

Introduction of pro-angiogenic cells into tissue-engineered (TE) constructs (prevascularisation) is a promising approach to overcome delayed neovascularisation of such constructs post-implantation. Accordingly, in this study, we examined the contribution of human dermal microvascular endothelial cells (HDMECs) and human dermal fibroblasts (HDFs) alone and in combination on the formation of new blood vessels in ex-ovo chick chorioallantoic membrane (CAM) assay.

METHODS

Poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) and polycaprolactone (PCL) were first examined in terms of their physical, mechanical, and biological performances. The effect of gelatin coating and co-culture conditions on enhancing endothelial cell viability and growth was then investigated. Finally, the angiogenic potential of HDMECs and HDFs were assessed macroscopically and histologically after seeding on simple electrospun PHBV scaffolds either in isolation or in indirect co-culture using an ex-ovo CAM assay.

RESULTS

The results demonstrated that PHBV was slightly more favourable than PCL for HDMECs in terms of cell metabolic activity. The gelatin coating of PHBV scaffolds and co-culture of HDMECs with HDFs both showed a positive impact on HDMECs viability and growth. Both cell types induced angiogenesis over 7 days in the CAM assay either in isolation or in co-culture. The introduction of HDMECs to the scaffolds resulted in the production of more blood vessels in the area of implantation than the introduction of HDFs, but the co-culture of HDMECs and HDFs gave the most significant angiogenic activity.

CONCLUSION

Our findings showed that the in vitro prevascularisation of TE constructs with HDMECs and HDFs alone or in co-culture promotes angiogenesis in implantable TE constructs.

Fabrication of 3D-Printed Biodegradable Porous Scaffolds Combining Multi-Material Fused Deposition Modeling and Supercritical CO2 Techniques

The fabrication of porous materials for tissue engineering applications in a straightforward manner is still a current challenge. Herein, by combining the advantages of two conventional methodologies with additive manufacturing, well-defined objects with internal and external porosity were produced. First of all, multi-material fused deposition modeling (FDM) allowed us to prepare structures combining poly (ε-caprolactone) (PCL) and poly (lactic acid) (PLA), thus enabling to finely tune the final mechanical properties of the printed part with modulus and strain at break varying from values observed for pure PCL (modulus 200 MPa, strain at break 1700%) and PLA (modulus 1.2 GPa and strain at break 5-7%). More interestingly, supercritical CO2 (SCCO2) as well as the breath figures mechanism (BFs) were additionally employed to produce internal (pore diameters 80-300 µm) and external pores (with sizes ranging between 2 and 12 μm) exclusively in those areas where PCL is present. This strategy will offer unique possibilities to fabricate intricate structures combining the advantages of additive manufacturing (AM) in terms of flexibility and versatility and those provided by the SCCO2 and BFs to finely tune the formation of porous structures.

Three-Dimensional Printed Polycaprolactone Scaffolds for Bone Regeneration Success and Future Perspective

IMPACT STATEMENT

Cells need a home to proliferate and remodel; biomimicry of the microarchitecture and microenvironment is important, and with 10 years of history in more than 20,000 clinical applications of 3D printed medical grade polycaprolactone scaffolds, we present the lessons learnt and project the future.

Dual-Peptide-Functionalized Nanofibrous Scaffolds Recruit Host Endothelial Progenitor Cells for Vasculogenesis to Repair Calvarial Defects

Vasculogenesis (de novo formation of vessels) induced by endothelial progenitor cells (EPCs) is requisite for vascularized bone regeneration. However, there exist few available options for promoting vasculogenesis within artificial bone grafts except for exogenous EPC transplantation, which suffers from the source of EPC, safety, cost, and time concerns in clinical applications. This study aimed at endogenous EPC recruitment for vascularized bone regeneration by using a bioinspired EPC-induced graft. The EPC-induced graft was created by immobilizing two bioactive peptides, WKYMVm and YIGSR, on the surface of poly(ε-caprolactone) (PCL)/poliglecaprone (PGC) nanofibrous scaffolds via a polyglycolic acid (PGA)-binding peptide sequence. Remarkable immobilization efficacy of WKYMVm and YIGSR peptides and their sustained release (over 14 days) from scaffolds were observed. In vivo and in vitro studies showed robust recruitment of EPCs, which subsequently contributed to early vasculogenesis and ultimate bone regeneration. The dual-peptide-functionalized nanofibrous scaffolds proposed in this study provide a promising therapeutic strategy for vasculogenesis in bone defect repair.