Biological and Mechanical Properties of Platelet-Rich Fibrin Membranes after Thermal Manipulation and Preparation in a Single-Syringe Closed System

Autologous and Heterologous Minor and Major Bone Regeneration with Platelet-Derived Growth Factors

AIM

This review aims to explore the clinical applications, biological mechanisms, and potential benefits of concentrated growth factors (CGFs), autologous materials, and xenografts in bone regeneration, particularly in dental treatments such as alveolar ridge preservation, mandibular osteonecrosis, and peri-implantitis.

MATERIALS AND METHODS

A systematic literature search was conducted using databases like PubMed, Scopus, and Web of Science, with keywords such as "bone regeneration" and "CGF" from 2014 to 2024. Only English-language clinical studies involving human subjects were included. A total of 10 studies were selected for qualitative analysis. Data were processed through multiple stages, including title and abstract screening and full-text evaluation.

CONCLUSION

The findings of the reviewed studies underscore the potential of the CGF in enhancing bone regeneration through stimulating cell proliferation, angiogenesis, and extracellular matrix mineralization. Autologous materials have also demonstrated promising results due to their biocompatibility and capacity for seamless integration with natural bone tissue. When combined with xenografts, these materials show synergistic effects in improving bone quantity and quality, which are crucial for dental implant success. Future research should focus on direct comparisons of different techniques, the optimization of protocols, and broader applications beyond dental medicine. The integration of CGFs and autologous materials into routine clinical practice represents a significant advancement in regenerative dental medicine, with the potential for improved patient outcomes and satisfaction.

In vitro ultrastructure and biodegradation of activated plasma albumin gel derived from human samples: A prospective observational study

BACKGROUND

In soft tissue regeneration, the clinical efficacy of fibrin membranes has been a pressing concern. The key to this efficacy lies in the stability of membrane and its controlled absorption. Human serum albumin, with its influence on the formation and stability of fibrin networks, could hold the key to developing a more stable alternative. This study investigates the ultrastructure and biodegradability of plasma albumin-activated gel, a potential game-changer in the field.

METHODS

Blood samples were collected from the participants and centrifuged to obtain the concentrated growth factor. The poor platelet plasma syringe was placed inside the activated plasma albumin gel device. The ultrastructure of the membrane was examined using a scanning electron microscope (SEM). The weight difference was measured over 21 days to investigate the biodegradability of the samples.

RESULTS

Twenty-two samples were prepared from six individuals (three males and three females). Based on SEM images, activated albumin gel after 21 days in Hank's solution exhibited a significant decrease in density and evident signs of surface degradation. The weight was significantly reduced after 21 days (p < 0.05).

CONCLUSION

In the present study, the investigation of the ultrastructure and biodegradability of activated albumin gel showed that, based on the observed weight difference, the amount of biodegradation is high, and it may be necessary to use a thicker membrane compared to the conventional thickness of the connective tissue graft.

KEY POINTS

Enhanced stability and biocompatibility: The study highlights plasma albumin-activated gel's potential as a soft tissue scaffold, demonstrating significant biodegradation and structural changes that support cell infiltration and nutrient exchange, essential for tissue regeneration. Controlled degradation profile: Plasma albumin gel offers a prolonged biodegradation period compared to conventional fibrin membranes, making it suitable for applications requiring stable, long-lasting scaffolds in soft tissue regeneration. Future clinical applications: Findings suggest that thicker plasma albumin membranes may be needed for optimal effectiveness, paving the way for further exploration in clinical trials and animal models to validate this approach in soft tissue grafting.

PLAIN LANGUAGE SUMMARY

This study investigates plasma albumin-activated gel as a promising material for supporting soft tissue repair, particularly in periodontal regeneration. Traditional materials, such as fibrin membranes, are often used to aid healing, but their rapid breakdown can limit effectiveness in the body. Plasma albumin, a protein naturally found in human blood, might offer a more stable alternative by forming a longer-lasting structure. In this study, researchers processed blood samples from participants to create the gel, examining its structure under a powerful microscope and tracking changes in weight over 21 days to assess its breakdown. Results showed that the gel gradually became less dense and more porous, allowing for cell movement and nutrient flow-both critical for tissue repair. Additionally, a significant reduction in weight indicated a controlled breakdown over time. These findings suggest that plasma albumin-activated gel may serve as a more durable scaffold for soft tissue regeneration, potentially improving healing outcomes in periodontal applications where a stable, longer-lasting material is needed.

Development of a super-hydrophilic anaerobic tube for the optimization of platelet-rich fibrin

Horizontal platelet-rich fibrin (H-PRF) contains a variety of bioactive growth factors and cytokines that play a key role in the process of tissue healing and regeneration. The blood collection tubes used to produce Solid-PRF (plasmatrix (PM) tubes) have previously been shown to have a great impact on the morphology, strength and composition of the final H-PRF clot. Therefore, modification to PM tubes is an important step toward the future optimization of PRF. To this end, we innovatively modified the inner wall surface of the PM tubes with plasma and adjusted the gas environment inside the PM tubes to prepare super-hydrophilic anaerobic plasmatrix tubes (SHAP tubes). It was made anaerobic for the preparation of H-PRF with the aim of improving mechanical strength and bioactivity. The findings demonstrated that an anaerobic environment stimulated platelet activation within the PRF tubes. After compression, the prepared H-PRF membrane formed a fibrous cross-linked network with high fracture strength, ideal degradation characteristics, in addition to a significant increase in size. Thereafter, the H-PRF membranes prepared by the SHAP tubes significantly promoted collagen synthesis of gingival fibroblast and the mineralization of osteoblasts while maintaining excellent biocompatibility, and advantageous antibacterial properties. In conclusion, the newly modified PRF tubes had better platelet activation properties leading to better mechanical strength, a longer degradation period, and better regenerative properties in oral cell types including gingival fibroblast and alveolar osteoblasts. It also improves the success rate of H-PRF preparation in patients with coagulation dysfunction and expands the clinical application scenario.

Platelet Power: Revitalizing Endodontics With Scaffolds

This article provides an overview of a biologically based method for restoring damaged tooth structures and pulp tissues known as regenerative endodontics. It explores the concept of regenerative endodontics, its tissue engineering approach, and its application in maintaining vitality. The article discusses the significance of the factors affecting growth, scaffolds, and stem cells being the three tissue engineering components involved in the regeneration of pulp tissues. It also delves into the classification of scaffolds and the role of platelet-rich fibrin (PRF) and platelet-rich plasma (PRP) as biological scaffolds. The methodology section details the search process for relevant studies, and the review section presents research findings associated with PRF and its application in regeneration and repair of tissue. The article concludes by highlighting the potential of advanced PRF and injectable PRF in regenerative endodontics, with a focus on their impact on tissue regeneration and healing.

Platelet-rich fibrin as an autologous biomaterial for bone regeneration: mechanisms, applications, optimization

Platelet-rich fibrin, a classical autologous-derived bioactive material, consists of a fibrin scaffold and its internal loading of growth factors, platelets, and leukocytes, with the gradual degradation of the fibrin scaffold and the slow release of physiological doses of growth factors. PRF promotes vascular regeneration, promotes the proliferation and migration of osteoblast-related cells such as mesenchymal cells, osteoblasts, and osteoclasts while having certain immunomodulatory and anti-bacterial effects. PRF has excellent osteogenic potential and has been widely used in the field of bone tissue engineering and dentistry. However, there are still some limitations of PRF, and the improvement of its biological properties is one of the most important issues to be solved. Therefore, it is often combined with bone tissue engineering scaffolds to enhance its mechanical properties and delay its degradation. In this paper, we present a systematic review of the development of platelet-rich derivatives, the structure and biological properties of PRF, osteogenic mechanisms, applications, and optimization to broaden their clinical applications and provide guidance for their clinical translation.

Water-Insoluble, Thermostable, Crosslinked Gelatin Matrix for Soft Tissue Implant Development

In this present study, the material science background of crosslinked gelatin (GEL) was investigated. The aim was to assess the optimal reaction parameters for the production of a water-insoluble crosslinked gelatin matrix suitable for heat sterilization. Matrices were subjected to enzymatic degradation assessments, and their ability to withstand heat sterilization was evaluated. The impact of different crosslinkers on matrix properties was analyzed. It was found that matrices crosslinked with butanediol diglycidyl ether (BDDE) and poly(ethylene glycol) diglycidyl ether (PEGDE) were resistant to enzymatic degradation and heat sterilization. Additionally, at 1 v/v % crosslinker concentration, the crosslinked weight was lower than the starting weight, suggesting simultaneous degradation and crosslinking. The crosslinked weight and swelling ratio were optimal in the case of the matrices that were crosslinked with 3% and 5% v/v BDDE and PEGDE. FTIR analysis confirmed crosslinking, and the reduction of free primary amino groups indicated effective crosslinking even at a 1% v/v crosslinker concentration. Moreover, stress-strain and compression characteristics of the 5% v/v BDDE crosslinked matrix were comparable to native gelatin. Based on material science measurements, the crosslinked matrices may be promising candidates for scaffold development, including properties such as resistance to enzymatic degradation and heat sterilization.

Can concentrated growth factor prevent postoperative complications of impacted third molar surgery? A split-mouth randomized double-blind trial

OBJECTIVES

The purpose of the present study was to evaluate the effect of concentrated growth factor (CGF) on prevention of postoperative complications in the impacted third molar extraction.

MATERIALS AND METHODS

A total of 25 healthy patients with symmetrical bilaterally impacted third molars (50 extraction sites) were enrolled in this split-mouth, randomized, double-blind clinical trial. Third molar extractions were performed in both sites of the mandible at the same appointment. Randomization was performed using a coin toss to choose the test and control sites. CGF was placed in the extraction socket and the socket was sutured (test group), while the contralateral socket was only sutured (control group). Each patient acted as their own control. The primary outcome were pain assessed by visual analog scale (VAS) and facial swelling on the1st, 3rd and 7th postoperative days. The secondary outcomes were bone healing in extraction sockets through alveolar bone height (ABH) and alveolar bone density (ABD) evaluated by cone beam computed tomography (CBCT) immediately after extraction and in the 3rd and 6th months.

RESULTS

Twenty-five patients (12 female, 13 male; mean age 29.17) with bilateral impacted third molars participated in the study. A statistically significant reduction in pain was determined on the 3rd and 7th postoperative days in the CGF sites compared to the control sites while no statistically significant difference was found between the groups on the 1st postoperative day (3rd day, p = 0.009; 7th day, p = 0.039). There were no statistically significant differences in facial swelling and bone healing between the test and control groups at different time intervals, although the data obtained were slightly favoring the CGF group (p > 0.05). There were no serious adverse effects such as infection, alveolitis, paraesthesia, fracture through the follow-up period in all of the cases.

CONCLUSION

The study has demonstrated the effect of CGF on relieving the severity of pain after the third molar extraction.

CLINICAL RELEVANCE

Placement of CGF in the extraction socket could relieve postoperative pain and reduce patient discomfort after the third molar extraction. CGF is recommended during the third molar extraction due to its good biological effects, low cost and simple preparation procedures.

TRIAL REGISTRATION NUMBER

ChiCTR2300077819.

Platelet rich fibrin and simvastatin-loaded pectin-based 3D printed-electrospun bilayer scaffold for skin tissue regeneration

Designing multifunctional wound dressings is a prerequisite to prevent infection and stimulate healing. In this study, a bilayer scaffold (BS) with a top layer (TL) comprising 3D printed pectin/polyacrylic acid/platelet rich fibrin hydrogel (Pec/PAA/PRF) and a bottom nanofibrous layer (NL) containing Pec/PAA/simvastatin (SIM) was produced. The biodegradable and biocompatible polymers Pec and PAA were cross-linked to form hydrogels via Ca2+ activation through galacturonate linkage and chelation, respectively. PRF as an autologous growth factor (GF) source and SIM together augmented angiogenesis and neovascularization. Because of 3D printing, the BS possessed a uniform distribution of PRF in TL and an average fiber diameter of 96.71 ± 18.14 nm was obtained in NL. The Young's modulus of BS was recorded as 6.02 ± 0.31 MPa and its elongation at break was measured as 30.16 ± 2.70 %. The wound dressing gradually released growth factors over 7 days of investigation. Furthermore, the BS significantly outperformed other groups in increasing cell viability and in vivo wound closure rate (95.80 ± 3.47 % after 14 days). Wounds covered with BS healed faster with more collagen deposition and re-epithelialization. The results demonstrate that the BS can be a potential remedy for skin tissue regeneration.

Effect of thermal manipulation on the biological and mechanical characteristics of horizontal platelet rich fibrin membranes

BACKGROUD

Regardless of application scenarios, proper mechanical characteristics and degradation properties are prerequisites for horizontal platelet rich fibrin (H-PRF) to manifest its ability. Among the methods used to modify PRF, thermal manipulation is promising as it is easy to handle without adding extra additives. Yet there is no consensus on optimal temperature treatment. This study aimed to investigate the effects of heating on the biological and mechanical characteristics of H-PRF and explore the optimum heating temperature for H-PRF thermal treatment.

METHODS

We employed a series of temperature gradients, room temperature, 50℃, 75℃, 90℃, 105℃. The microstructure and the mechanical properties were recorded by Scanning Electron Microscope (SEM) and tensile strength tests respectively. The degradation rate of H-PRF membranes was examined by digestion assay with plasmin and trypsin. The viability of cells within H-PRF membranes and the proliferation of osteoblasts cultured with extracts from different H-PRF groups was evaluated using CCK-8 assays.

RESULTS

Compared with the nonheated group, overheated manipulation beyond 90℃ can significantly prolong the degradation properties for up to 3 to 4 weeks and enhance the mass stress of H-PRF membranes. A high-temperature treatment of 105℃ accompanied by the cell activity beneath H-PRF reduced more than half, and thus, the biological effect on human osteoblasts (hFOBs) also reduced dramatically.

CONCLUSIONS

High thermal manipulation can prolong the degradation properties and enhance the mechanical properties of PRF membranes accompanied by the loss of biological effect.

The Effects of Platelet-Rich Fibrin in the Behavior of Mineralizing Cells Related to Bone Tissue Regeneration-A Scoping Review of In Vitro Evidence

Platelet-rich fibrin (PRF) is a second-generation blood concentrate that serves as an autologous approach for both soft and hard tissue regeneration. It provides a scaffold for cell interaction and promotes the local release of growth factors. PRF has been investigated as an alternative to bone tissue therapy, with the potential to expedite wound healing and bone regeneration, though the mechanisms involved are not yet fully understood. This review aims to explore the in vitro evidence of PRF's effects on the behavior of mineralizing cells related to bone tissue regeneration. A systematic electronic search was conducted up to August 2023, utilizing three databases: PubMed, Web of Science, and Scopus. A total of 76 studies were selected, which presented in vitro evidence of PRF's usefulness, either alone or in conjunction with other biomaterials, for bone tissue treatment. PRF membranes' influence on the proliferation, differentiation, and mineralization of bone cells is linked to the constant release of growth factors, resulting in changes in crucial markers of bone cell metabolism and behavior. This further reinforces their therapeutic potential in wound healing and bone regeneration. While there are some notable differences among the studies, the overall results suggest a positive effect of PRF on cell proliferation, differentiation, mineralization, and a reduction in inflammation. This points to its therapeutic potential in the field of regenerative medicine. Collectively, these findings may help enhance our understanding of how PRF impacts basic physiological processes in bone and mineralized tissue.

Histological, Immunohistochemical, Biomechanical, and Wettability Evaluations of the Leukocyte- and Platelet-Rich Fibrin Membranes Derived from Canine Blood

This study aimed to perform histological, immunohistochemical, biomechanical, and wettability assessments of leukocyte- and platelet-rich fibrin (L-PRF) membranes obtained from the blood of healthy dogs. Ten client-owned Labrador Retriever dogs were enrolled. Blood samples were obtained from the external jugular vein using a vacuum tube without anticoagulant, which was immediately centrifuged at 400g for 12 min in a dedicated centrifuge. The L-PRF clot was removed from the tube, and the red clot was released from the buffy coat using a spatula. The membrane was produced using a PRF box. Histological examination identified the three portions of the L-PRF membranes. The first portion was composed mainly of red blood cells with the presence of a low number of leukocytes among them. The second portion was composed of white blood cells, mainly neutrophils. The third portion was composed of the fibrin network which was characterized by acidophilic staining. The immunohistochemical analysis showed that vascular endothelial growth factor and platelet-derived growth factor were expressed in all samples at different intensities, both in cellular components and fibrin mesh. The tensile test and wettability assessments were measured in membranes 30 min and 3 h after production. The 30 min L-PRF membranes supported twice the ultimate tensile strength compared to 3 h L-PRF membranes. The wettability of the 30 min sample membranes was statistically higher than the 3 h sample membranes. In conclusion, the centrifugation protocol allowed production of the L-PRF membrane using canine blood and this was confirmed by histological and immunohistochemical analysis. The mechanical resistance and wettability of the L-PRF membrane were significantly reduced over time.

Platelet-Rich Plasma Power-Mix Gel (ppm)-An Orthobiologic Optimization Protocol Rich in Growth Factors and Fibrin

Platelet- and fibrin-rich orthobiologic products, such as autologous platelet concentrates, have been extensively studied and appreciated for their beneficial effects on multiple conditions. Platelet-rich plasma (PRP) and its derivatives, including platelet-rich fibrin (PRF), have demonstrated encouraging outcomes in clinical and laboratory settings, particularly in the treatment of musculoskeletal disorders such as osteoarthritis (OA). Although PRP and PRF have distinct characteristics, they share similar properties. The relative abundance of platelets, peripheral blood cells, and molecular components in these orthobiologic products stimulates numerous biological pathways. These include inflammatory modulation, augmented neovascularization, and the delivery of pro-anabolic stimuli that regulate cell recruitment, proliferation, and differentiation. Furthermore, the fibrinolytic system, which is sometimes overlooked, plays a crucial role in musculoskeletal regenerative medicine by regulating proteolytic activity and promoting the recruitment of inflammatory cells and mesenchymal stem cells (MSCs) in areas of tissue regeneration, such as bone, cartilage, and muscle. PRP acts as a potent signaling agent; however, it diffuses easily, while the fibrin from PRF offers a durable scaffolding effect that promotes cell activity. The combination of fibrin with hyaluronic acid (HA), another well-studied orthobiologic product, has been shown to improve its scaffolding properties, leading to more robust fibrin polymerization. This supports cell survival, attachment, migration, and proliferation. Therefore, the administration of the "power mix" containing HA and autologous PRP + PRF may prove to be a safe and cost-effective approach in regenerative medicine.

Platelet rich fibrin is not a barrier membrane! Or is it?

Platelet-rich fibrin (PRF) is widely used in dentistry and other fields of medicine, and its use has become popular in dental implantology. In several published studies, PRF has been used as a barrier membrane. A barrier membrane is a sheet of a certain material that acts as a biological and mechanical barrier against the invasion of cells that are not involved in bone formation, such as epithelial cells. Among the basic requirements of a 'barrier membrane, occlusivity, stiffness, and space maintenance are the criteria that PRF primarily lacks; therefore, it does not fall under the category of barrier membranes. However, there is evidence that PRF membranes are useful in significantly improving wound healing. Does the PRF membrane act as a barrier? Should we think of adding or subtracting some points from the ideal requirements of a barrier membrane, or should we coin a new term or concept for PRF that will incorporate some features of a barrier membrane and be a combination of tissue engineering and biotechnology? This review is aimed at answering the basic question of whether the PRF membrane should be considered a barrier membrane or whether it is something more beyond the boundaries of a barrier membrane.

The use of platelet-rich fibrin in vestibuloplasty: A 36-month follow-up technique report

INTRODUCTION

Vestibuloplasty is a mucogingival procedure that aims to increase the vestibule and the amount of keratinized tissue (KT) around teeth and dental implants. Currently, the gold standard in this procedure is still represented by free gingival grafts (FGGs); however, they require a second surgical site, which means more morbidity for the patient and a higher risk of surgical complications, as well as surgical time and chromatic alteration of the recipient area.

CASE PRESENTATION

This is a description of the vestibuloplasty technique with platelet-rich fibrin (PRF) in a 35-year-old female patient with a thin gingival phenotype and no medical history of interest. The reason for consultation was tooth sensitivity during brushing and the presence of recessions in the fifth sextant.

CONCLUSIONS

The use of PRF as a graft biomaterial in vestibuloplasty is a valid and effective option as an alternative to secondary epithelialization of the surgical site, as well as to FGGs, with acceptable results in terms of KT gain and root coverage, and with minimal postoperative discomfort.

KEY POINTS

Why is this case new information? The use of PRF is an interesting option as an alternative to second-intention healing, as FGGs in vestibuloplasty. What are the keys to successful management of this case? The most important part of the membranes is the part that was in close relation to the erythrocyte fraction in the blood collection tube, so this part must be oriented toward the recipient bed. A minimum of four membranes should be obtained, overlapping one on top of the other. What are the primary limitations to success in this case? The stability of the PRF.

Can Our Blood Help Ensure Antimicrobial and Anti-Inflammatory Properties in Oral and Maxillofacial Surgery?

In recent decades, the potential of PRF has been extensively studied. The number of studies about PRF has increased three times since the year 2012, but the full spectrum of its fundamental properties, such as antimicrobial and anti-inflammatory activity, is not clearly described. In oral and maxillofacial surgery, PRF is described in alveolar ridge preservation, orthognathic surgery, cleft lip and palate surgery, maxillary sinus augmentation, and dental implant placement as demonstrating favorable results and its clinical advantages. The structural complexity, inhomogeneous nature, and clotting ability of PRF make its antimicrobial effect evaluation complicated. Nevertheless, most of the used antimicrobial testing methods are based on antibacterial agent diffusion ability in culture media. Because the oral and maxillofacial region is the most frequent area of PRF application, its antimicrobial activity evaluation also prevails in the oral microbiome. PRF's biological potential is highly dependent on the specific preparation protocol and methodology used; it should be carefully prepared and kept under proper conditions to keep cellular content alive. PRF's influence on living cells demonstrates a stimulating effect on bone regeneration, and an angiogenetic effect, and it provides anti-inflammatory activity. According to analyzed studies, PRF demonstrated success in oral and maxillofacial surgery in various methods of application. Antibacterial and anti-inflammatory properties were proven by antibacterial activity against different bacterial species, sustained growth factor, sustained release, and cell activity on the material application. Accurately and correctly prepared PRF can ensure antibacterial and anti-inflammatory properties, and it can be a beneficial clinical tool in oral and maxillofacial surgery.

In Vitro Assessment of Lyophilized Advanced Platelet-Rich Fibrin from Dogs in Promotion of Growth Factor Release and Wound Healing

Advanced platelet-rich fibrin (A-PRF) induces more proliferation and migration of fibroblasts compared with standard PRF, but it being freshly prepared prior to it being applied is necessary. Therefore, this study aimed to determine the effect of lyophilized A-PRF on growth factor release and cell biological activity. Blood samples were collected from six dogs and processed for fresh and lyophilized A-PRF. The growth factors released included transforming growth factor beta-1 (TGF-β1), vascular endothelial growth factor-A (VEGFA), and platelet-derived growth factor-BB (PDGF-BB), and the fibroblast proliferation as well as wound closure enhancement of both products were compared. The results showed that TGF-β1, PDGF-BB, and VEGFA were continually released from lyophilized A-PRF for over 72 h. Lyophilized A-PRF released significantly more accumulated VEGEA and a tendency to release more TGF-β1 at 72 h as well as VEGFA at 24 h and 72 h than fresh A-PRF. Moreover, lyophilized A-PRF increased fibroblast proliferation and induced a significantly faster wound closure than the control, while no significant difference between fresh and lyophilized A-PRF was found. In conclusion, the lyophilization of canine A-PRF can preserve the release of growth factors and has similar biological activities to a fresh preparation. This encourages the substitution of lyophilized A-PRF instead of fresh A-PRF in regenerative treatments in which the stability of the product is concerned.

Platelet Rich Fibrin Membrane Grafting After Laser Excision for Oral Mucosal Lesions

Platelet rich fibrin (PRF) is a novel surgical biomaterial which has shown immense healing and regenerative potential with diverse clinical applications. Surgical excision is a routinely employed treatment modality for mucosal oral lesions with or without grafting or repair of the base of the wound. We proposed a hypothesis that covering of the base of excised lesion with this platelet rich fibrin membrane can accelerate the rate of physiological healing process and regeneration. To evaluate the role, efficacy, advantages and adverse effects if any, of placement of PRF membrane grafts over surgical excision sites of oral mucosal lesions. Platelet rich fibrin membrane graft was prepared as per recommendation and established protocols. Patients were selected for surgical excision of localized, superficial oral mucosal lesions after meticulous clinical and radiological considerations and informed consent was taken. After laser excision with safe margins, the base of wound was covered with PRF membrane graft, stitched in place by 3-0 vicryl sutures. The operated site was clinically evaluated at regular intervals and a healing score was calculated and statistically tabulated on the basis of various parameters of healing. A total of 34 patients were included in the study with a male preponderance (21 males and 13 females). Satisfactory and clinically acceptable wound healing was observed in most of the patient with minimal morbidities. Surgical site demonstrated good healing score and clinically complete healing with good epithelialisation was achieved in all patients. Platelet rich fibrin membrane is an effective grafting biomaterial after excision of oral mucosal lesions as it enhances the rate of healing with minimal complications. We recommend further multicentre studies with higher sample size to explore its utility and clinical applications in different avenues of oral and head neck surgery.

Comparison of physical, mechanical and biological effects of leucocyte-PRF and advanced-PRF on polyacrylamide nanofiber wound dressings: In vitro and in vivo evaluations

Platelet-rich fibrin (PRF) is extracted from the blood without biochemical interference and, also, with the ability of a long-term release of growth factors that can stimulate tissue repair and regerenation. Here, leucocyte- and platelet-rich fibrin (L-PRF) and advanced platelet-rich fibrin (A-PRF) were extracted and utilized for the creation of nanofibers containing polyacrylamide (PAAm), PAAm / L-PRF and PAAm / A-PRP through electrospinning processing technique. The effect of the type of PRF on the physical, mechanical and biological properties of the resultant nanofiberous wound dressings are thoroughly evaluated. The results presented in the current study reveals that the fiber diameter is grealtly reduced through the utilization of L-PRF. In addition, mechanical property is also positively affected by L-PRF and the degradation rate is found to be higher compared to A-PRF group. The L929 cells proliferation and adhesion, angiogenesis potential and wound healing ability was significantly higher in PAAm/A-PRF nanofibers compared to pure PAAm and PAAm/L-PRF nanofibers owed to the release of vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF). Overall, the utilization of L-PRF or A-PRF can improve the physical, mechanical and biological behavior of nanofiber making them an ideal candidate for wound dressings, with the emphasis on the skin tissue repair and regeneration applications.

Coaxial electrospun angiogenic nanofiber wound dressing containing advanced platelet rich-fibrin

Advanced platelet-rich fibrin (A-PRF) provides long-term release of growth factors that potentially accelerate wound healing. In this study, core-shell nanofibrous structure of polyvinyl alcohol (PVA) core and gelatin (Gel) shell containing A-PRF is fabricated through coaxial electrospinning method. PVA/(Gel/A-PRF) core-shell nanofibers had the highest porosity, specific surface area and hydrophilicity among all the studied nanofibers. PVA/(Gel/A-PRF) core-shell nanofibers with a tensile stress of 7.43 ± 0.38 MPa and an elastic modulus of 102.05 ± 9.36 MPa had higher mechanical properties than PVA/Gel/A-PRF and PVA/Gel blend nanofibers. PVA/(Gel/A-PRF) nanofibers had a 47.41 ± 1.97 % degradability over 7 days of immersion in PBS. The release of VEGF and PDGF-AB growth factors from PVA/(Gel/A-PRF) core-shell nanofibers and PVA/Gel/A-PRF blend nanofibers were evaluated. It was shown that L929 cell proliferation and adhesion on PVA/(Gel/A-PRF) core-shell nanofibers were significantly higher than other samples. Also, chicken chorioallantoic membrane (CAM) assay revealed that the highest angiogenic potential among the studied samples related to PVA/(Gel/A-PRF) sample. In vivo studies on a rat model showed wound closure for PVA/(Gel/A-PRF) group was 97.83 ± 2.03 % after 11 days. Histopathological and immunohistochemical examinations approved the acceleration of wound healing by PVA/(Gel/A-PRF) core-shell nanofiber dressing. The results strongly recommend the use of PVA/(Gel/A-PRF) core-shell nanofiber dressing for the repair of full-thickness wounds.

Application of Injectable, Crosslinked, Fibrin-Containing Hyaluronic Acid Scaffolds for In Vivo Remodeling

The present research aimed to characterize soft tissue implants that were prepared with the use of crosslinked hyaluronic acid (HA) using two different crosslinkers and multiple reagent concentrations, alone or in combination with fibrin. The effect of the implants was evaluated in an in vivo mouse model, after 4 weeks in one group and after 12 weeks in the other. The explants were compared using analytical methods, evaluating microscopic images, and a histology analysis. The kinetics of the degradation and remodeling of explants were found to be greatly dependent on the concentration and type of crosslinker; generally, divinyl sulfone (DVS) resists degradation more effectively compared to butanediol diglycidyl ether (BDDE). The presence of fibrin enhances the formation of blood vessels, and the infiltration of cells and extracellular matrix. In summary, if the aim is to create a soft tissue implant with easier degradation of the HA content, then the use of 2-5% BDDE is found to be optimal. For a longer degradation time, 5% DVS is the more suitable crosslinker. The use of fibrin was found to support the biological process of remodeling, while keeping the advances of HA in void filling, enabling the parallel degradation and remodeling processes.

Tensile Strength Essay Comparing Three Different Platelet-Rich Fibrin Membranes (L-PRF, A-PRF, and A-PRF+): A Mechanical and Structural In Vitro Evaluation

Predictable outcomes intended by the application of PRF (platelet-rich fibrin) derivative membranes have created a lack of consideration for their consistency and functional integrity. This study aimed to compare the mechanical properties through tensile strength and analyze the structural organization among the membranes produced by L-PRF (leukocyte platelet-rich fibrin), A-PRF (advanced platelet-rich fibrin), and A-PRF+ (advanced platelet-rich fibrin plus) (original protocols) that varied in centrifugation speed and time. L-PRF (n = 12), A-PRF (n = 19), and A-PRF+ (n = 13) membranes were submitted to a traction test, evaluating the maximum and average traction. For maximum traction, 0.0020, 0.0022, and 0.0010 N·mm−2 were obtained for A-PRF, A-PRF+, and L-PRF, respectively; regarding the average resistance to traction, 0.0012, 0.0015, and 0.006 N·mm−2 were obtained, respectively (A-PRF+ > A-PRF > L-PRF). For all groups studied, significant results were found. In the surface morphology observations through SEM, the L-PRF matrix showed a highly compact surface with thick fibers present within interfibrous areas with the apparent destruction of red blood cells and leukocytes. The A-PRF protocol showed a dense matrix composed of thin and elongated fibers that seemed to follow a preferential and orientated direction in which the platelets were well-adhered. Porosity was also evident with a large diameter of the interfibrous spaces whereas A-PRF+ was the most porous platelet concentrate with the greatest fiber abundance and cell preservation. Thus, this study concluded that A-PRF+ produced membranes with significant and higher maximum traction results, indicating a better viscoelastic strength when stretched by two opposing forces.

Treatment of oroantral communication with Platelet-Rich Fibrin: A systematic review

BACKGROUND

Oroantral communication (OAC) is the opening between the maxillary sinus and the oral cavity, which constitutes a gate for the mucosal infection in the maxillary sinus. On the other hand, an OAF develops when the OAC does not close spontaneously, remains manifest and is epithelialized. Several methods have been proposed to solve these situations, however, they are associated with increased postoperative morbidity and/or higher associated costs and require some experience of the surgeon to perform them. To overcome these disadvantages, the use of Platelet-Rich Fibrin (PRF) is proposed. The present study aims to perform a systematic review of the literature, collecting cases in which PRF was used in the treatment of OACs/OAFs.

MATERIALS AND METHODS

An electronic search of the MEDLINE database (via PubMed) and Web of Science was performed using the following MeSH terms (Medical Subjects Headings): (oroantral communication OR oroantral fistula OR buccosinusal communication) AND (platelet-rich fibrin OR prf OR fibrin mesh). The criteria used were those described by the PRISMA® Statement. The search was not time-restricted and was updated to April 2021.

RESULTS

After searching, 11 articles were included that met the established criteria. In these, PRF was used alone or in combination with bi- or trilaminar techniques achieving complete resolution in 100% of cases (n = 116).

CONCLUSIONS

With the limitations of this study, it can be established that PRF can be used alone for the treatment of OACs/OAFs up to 5 mm and, in larger defects, it is advisable to combine it with bi- or trilaminar techniques. PRF is an effective therapeutic option, with minimal associated postoperative morbidity compared to other techniques and allows the position of the mucogingival junction to be preserved. Its combination with bone grafting improves the starting point before the replacement of the missing tooth with a dental implant.

Fabrication and evaluation of Cs/PVP sponge containing platelet-rich fibrin as a wound healing accelerator: An in vitro and in vivo study

Despite significant advances in surgery and postoperative care, there are still challenges in the treatment of wounds. In the current study, a freeze-dried chitosan (Cs)/polyvinylpyrrolidone (PVP) sponges containing platelet-rich fibrin (PRF at 1, 1.5 and 2% w/v) for wound dressing application is fabricated and fully characterized. Addition of 1% w/v of PRF to Cs/PVP (CS/PVP/1PRF) sample significantly increased the tensile strength (from 0.147 ± 0.005 to 0.242 ± 0.001 MPa), elastic modulus (from 0.414 ± 0.014 to 0.611 ± 0.022 MPa) and strain at break (from 53.4 ± 0.9 to 61.83 ± 1.17%) compared to Cs sample, and was hence selected as the optimal sample. The antibacterial activity of Cs/PVP/1PRF sponge wound dressing against E. coli and S. aureus was confirmed to be effective. Enzyme-linked immunosorbent assays revealed that the release of both VEGF and PDGF-AB from PRF powder, as well as PDGF-AB from Cs/PVP/1PRF sample was time-independent, but the release of VEGF from Cs/PVP/1PRF sample increased significantly with time. According to MTT and CAM assays, the Cs/PVP/1PRF sample significantly increased proliferation and angiogenic potential, respectively. Furthermore, in vivo studies demonstrated a 97.16 ± 1.55% wound closure for Cs/PVP/1PRF group after 14 days.

Autologous Platelet-Rich Fibrin Membrane to Augment Healing of Microfracture Has Better Macroscopic and Histologic Grades Compared With Microfracture Alone on Chondral Defects in a Rabbit Model

PURPOSE

To determine the in vivo effectiveness of a single-stage surgical procedure that combines microfracture and an autologous platelet-rich fibrin (PRF) membrane for cartilage repair in a rabbit model.

METHODS

Cartilage defects were created in the trochlear groove of the knees of adult white rabbits. Defects were divided into 2 treatment groups: microfracture only (control group) and microfracture covered by a PRF membrane (PRF group). To evaluate the repair cartilage, assessments were performed at 4, 12, and 24 weeks postoperatively using the International Cartilage Repair Society (ICRS) macroscopic scoring system and modified Wakitani histologic grading system.

RESULTS

The mean ICRS macroscopic scores in the control and PRF groups were 4.1 and 5.8, respectively, at 4 weeks (P = .0623); 6.3 and 9.8, respectively, at 12 weeks (P = .006); and 6.5 and 10.3, respectively, at 24 weeks (P = .010). The mean modified Wakitani scores in the control and PRF groups were 4.0 and 3.9, respectively, at 4 weeks (P > .999); 5.3 and 10.4, respectively, at 12 weeks (P = .006); and 2.6 and 7.4, respectively, at 24 weeks (P = .012).

CONCLUSIONS

The ICRS macroscopic scores and modified Wakitani scores showed that a single-stage surgical procedure combining microfracture and a PRF membrane was more effective than surgery with only microfracture for promoting cartilage repair.

CLINICAL RELEVANCE

A single-stage surgical procedure combining microfracture and an autologous PRF membrane is a potentially beneficial treatment method for cartilage defects that does not require using any xenocollagen membrane.

Lyophilised Platelet-Rich Fibrin: Physical and Biological Characterisation

Background: Platelet-rich fibrin (PRF) has gained popularity in craniofacial surgery, as it provides an excellent reservoir of autologous growth factors (GFs) that are essential for bone regeneration. However, the low elastic modulus, short-term clinical application, poor storage potential and limitations in emergency therapy use restrict its more widespread clinical application. This study fabricates lyophilised PRF (Ly-PRF), evaluates its physical and biological properties, and explores its application for craniofacial tissue engineering purposes. Material and methods: A lyophilisation method was applied, and the outcome was evaluated and compared with traditionally prepared PRF. We investigated how lyophilisation affected PRF’s physical characteristics and biological properties by determining: (1) the physical and morphological architecture of Ly-PRF using SEM, and (2) the kinetic release of PDGF-AB using ELISA. Results: Ly-PRF exhibited a dense and homogeneous interconnected 3D fibrin network. Moreover, clusters of morphologically consistent cells of platelets and leukocytes were apparent within Ly-PRF, along with evidence of PDGF-AB release in accordance with previously reports. Conclusions: The protocol established in this study for Ly-PRF preparation demonstrated versatility, and provides a biomaterial with growth factor release for potential use as a craniofacial bioscaffold.

Platelet-Rich Fibrin Membrane for Pterygium Surgery: Literature Review and Feasibility Assessment

Pterygium is a common ocular disease caused by abnormal cellular proliferation leading to abnormal fibrovascular growth of the conjunctiva. The main treatment is surgical removal; however, despite the improvement of surgical techniques and development of adjuvant therapies, postoperative recurrence, which can be as high as 89%, remains a challenge. Currently, pterygium excision with conjunctival autograft remains the preferred surgical technique, although there is no gold standard technique to prevent pterygium recurrence. We have conducted a thorough and comprehensive review of the scientific literature regarding the use of PRF membranes in pterygium surgery. We aim to assess the safety, effectiveness, and applicability of platelet-rich fibrin membrane for primary pterygium surgery and assess its possible benefits in resource-limited settings.

Cell Attachment Capacity and Compounds of Fibrin Membranes Isolated from Fresh Frozen Plasma and Cryoprecipitate

Fibrin membranes are widely used in regenerative medicine because they are biocompatible, biodegradable, contain growth factors, and support cell attachment. Most commonly they are produced from serum, but they can also be isolated from activated plasma. To increase the fibrinogen concentration of plasma, cryoprecipitate isolation is a possible solution. In this work, cryoprecipitate was prepared from fresh frozen plasma, isolated by plasmapheresis. The concentration of cellular elements, fibrinogen, total protein, and immunoglobulins among others was measured in different concentrations of cryoprecipitates. After activation with Ca-gluconate, fibrin membranes were produced in different thicknesses, and human mesenchymal stem cells were seeded onto the membranes. They were visualized by live-dead staining and their viability was determined by XTT. The platelet-derived growth factor AB content was quantified by ELISA. Our results showed that fibrinogen and platelet concentration can be multiplied in plasma by cryoprecipitate isolation, which affects the thickness and slightly the growth factor content of the membranes. According to live-dead staining, the thickness of the membranes does not influence cell attachment, and XTT measurement did not reveal a significant difference in cell attachment capacity either; however, a growing trend could be observed in the case of some membranes.

Effect of platelet-rich fibrin versus chitosan-based Axiostat hemostatic agent following dental extraction in cardiac patients on antiplatelet therapy: A comparative study

Background:

Platelet-rich fibrin (PRF) is a biomaterial that promotes wound healing. It has a fibrinous matrix wherein platelets, pro-inflammatory cytokines, and various growth factors along with few cells are entrapped while Chitosan is a naturally occurring cationic biopolymeric material that is derived from an animal product, chitin. It has demonstrated biological properties which include acceleration in wound healing, hemostasis, enhancement of immunological response, mucosal adhesion by eliciting biological responses, and anti-microbial action.

Aim:

The aim of this study was to evaluate the effect of PRF and Axiostat (A chitosan-based product) on hemostasis after tooth extraction among cardiac patients on antiplatelet medication.

Materials and Methods:

This prospective study was carried out on 300 patients undergoing tooth extraction. Participants were divided into two categories (n = 150, respectively) as Group I (PRF dressing) and Group II (Axiostat dressing). Time to achieve hemostasis was observed using a stopwatch. Average pain score calculation was performed using visual analog on the 7-day postoperative period. Descriptive statistics were done, and data analysis was performed using the Mann–Whitney U-test. P < 0.5 and < 0.001 were considered statistically significant and extremely significant, respectively.

Results:

Average pain score was 1.86 ± 0.06 in Group I and 1.05 ± 0.87 in Group II. Thus, lower postoperative pain was seen with Axiostat dressing. Hemostasis was achieved in Group II participants in 1.25 ± 0.06 min and in 1.89 ± 0.54 min in Group I. P < 0.01 was obtained, although no statistically significant difference in postoperative pain scores (P = 0.8) was seen.

Conclusion:

Chitosan is a superior wound dressing material in achieving hemostasis in cardiac patients on antiplatelet medication after tooth extraction.

PRF-Solution in Large Sinus Membrane Perforation with Simultaneous Implant Placement-Micro CT and Histological Analysis

Background: The purpose of the study was to analyze the efficacy of platelet-rich fibrin (PRF) as a single augmentation material for complicated cases of maxillary sinus floor elevation, resulting from membrane perforation or previous infections. Methods: Implant insertion in the posterior region of the maxilla was simultaneously performed with maxillary sinus floor augmentation. Schneiderian membrane elevation can be accompanied by extremely serious sinus membrane perforation, due to accidental tearing or intended incision for mucocele removal. PRFs were placed in the sinus cavity both for membrane sealing and sinus floor grafting. Radiological, histological and micro-CT analyses were performed. Implant survival was assessed every 6 months for 1 to 4 years, with a mean follow up of 1.8 years, after prosthetic loading. Radiological examinations were performed on CBCT at 9 and 12 and 36 months postoperatively and revealed improved degrees of radiopacity. Results: 19 implants were simultaneously placed in the course of nine maxillary sinus floor augmentation surgeries, with successful outcomes in terms of bone grafting and implant integration. New bone formation was evidenced 12 months postoperatively on radiological examination, micro-CT analysis, and histological analysis of a harvested bone segment from the augmented maxillary sinus. The mean gain in bone height of the sinus floor augmentation was 6.43 mm, with a maximum of 9 mm. The mean amount of vital bone obtained from histologic assessment was 52.30%, while bone volume/tissue volume ratio in micro-CT 3D had a mean of 50.32%. Conclusions: PRF may be considered as an alternative treatment for a single surgery of sinus augmentation with simultaneous implant placement, even in complicated cases with significant sinus membrane tearing.

Regenerative medicine: characterization of human bone matrix gelatin (BMG) and folded platelet-rich fibrin (F-PRF) membranes alone and in combination (sticky bone)

During the last two decades autologous platelet and leukocyte rich products (PRP; PRF), opened new perspectives in regenerative medicine. In particular regenerative dentistry played a pioneer role in the application of these products in bone regenerative cases. Many aspects of cytokines, such as, growth factor release, blood cell content and its characterization were reported, but some practical questions are still unanswered in the preparation of PRF membranes and sticky bones. A new folding technique was introduced that created a good quality, pliable, and strong F-PRF membrane with a dense fibrin network and more homogenous blood cell distribution. F-PRF produced a very promising sticky bone combined with human freeze-dried cortical bone matrix gelatin (BMG). There hasn’t been much focus on the quality and character of the applied bone and the optimal membrane/bone particle ratio has not been reported. A 0.125 g BMG/ml plasma (1 g/8 ml) seems like the ideal combination with maximal BMG adhesion capacity of the membrane. Particle distribution of BMG showed that 3/4 of the particles ranged between 300–1000 µ, the remnant 1/4 was smaller than 300 µ. The whole F-PRF membrane and its parts were compared with conventional A-PRF membrane concerning their resistance against proteolytic digestion. The F-PRF was superior to A-PRF, which dissolved within 4–5 days, while F-PRF was destroyed only after 11 days, so this provides a better chance for local bone morphogenesis. The F-PRF pieces had similar resistance to the whole intact one, so they can be ideal for surgical procedures without risk of fast disintegration.

Comparison of the effect of tranexamic acid at various concentrations on the degradation time of platelet-rich fibrin

This study aimed to compare platelet-rich fibrin (PRF) membranes obtained using a conventional method and those obtained using the tranexamic acid-mixed method at various concentrations in terms of appearance, weight, and degradation period. In this in vitro study, 20 PRF membranes were divided into four groups, including a conventional group manipulated using the conventional method. The remaining groups were prepared using tranexamic acid at concentrations of 50, 150, and 200 mg. The PRF membranes were evaluated for gross weight, degradation period, and daily remaining weight for 28 days. There were no statistically significant differences in gross weight among all the groups (p = 0.985). The 150 and 200 mg groups had a longer degradation period (more than 28 days), which was significantly longer than that of the control and 50 mg groups (p = 0.048). The daily remaining weights of the 150 and 200 mg groups were significantly greater than that of the control group observed from day 13 to the end of the experiment. The tranexamic acid-mixed technique had no effect on the appearance and weight of the PRF membranes. Moreover, the technique could delay their degradation.

Orchestrated cellular, biochemical, and biomechanical optimizations endow platelet-rich plasma-based engineered cartilage with structural and biomechanical recovery

Recently, biomaterials for cartilage regeneration has been intensively investigated. However, the development of scaffolds that capture regenerated cartilage with biomechanical and structural recovery has rarely been reported. To address this challenge, platelet-rich plasma (PRP)-based cartilage constructs with a well-orchestrated symphony of cellular, biochemical and biomechanical elements were prepared by simultaneously employing chondrogenic progenitor cells (CPCs) as a cell source, optimizing platelet concentration, and adding an enzyme-ion activator. It was shown that this triple-optimized PRP + CPC construct possessed increased biomechanical properties and suitable biochemical signals. The following in vitro study demonstrated that the triple-optimized PRP + CPC constructs generated cartilage-like tissue with higher expression levels of chondrogenic-specific markers, more deposition of cartilage-specific extracellular matrix (ECM), and greater biomechanical values than those of the other constructs. Twelve weeks after the construct was implanted in a cartilage defect in vivo, histological analysis, qPCR, and biomechanical tests collectively showed that the triple-optimized constructs yielded a more chondrocyte-like cell phenotype with a higher synthesis of Col-II and aggrecan. More importantly, the triple-optimized constructs facilitated cartilage regeneration with better biomechanical recovery than that of the other constructs. These results demonstrate the efficacy of the triple-optimization strategy and highlight the simplicity and potency of this PRP + CPC construct for cartilage regeneration.

•

Cartilage tissue engineering has been intensively investigated.

•

We designed a PRP-based construct with favorable cell source, reinforced scaffold and appropriate biofactors.

•

This designed construct can facilitate cartilage regeneration with biomechanical and structural recovery simultaneously.

•

The favorable performance of the proposed scaffolds highlights the triple-optimization strategy to improve cartilage engineering.

Functional repertoire of EV-associated miRNA profiles after lipoprotein depletion via ultracentrifugation and size exclusion chromatography from autologous blood products

Cartilage breakdown, inflammation and pain are hallmark symptoms of osteoarthritis, and autologous blood products such as citrate-anticoagulated platelet-rich plasma (CPRP) or hyperacute serum (hypACT) have been developed as a regenerative approach to rebuild cartilage, inhibit inflammation and reduce pain. However, mechanisms of action of these blood derivatives are still not fully understood, in part due to the large number of components present in these medical products. In addition, the discovery of extracellular vesicles (EVs) and their involvement in intercellular communication mediated by cargo molecules like microRNAs (miRNAs) opened up a whole new level of complexity in understanding blood products. In this study we focused on the development of an isolation protocol for EVs from CPRP and hypACT that can also deplete lipoproteins, which are often co-isolated in EV research due to shared physical properties. Several isolation methods were compared in terms of particle yield from CPRP and hypACT. To gain insights into the functional repertoire conveyed via EV-associated miRNAs, we performed functional enrichment analysis and identified NFκB signaling strongly targeted by CPRP EV miRNAs, whereas hypACT EV miRNAs affect IL6- and TGFβ/SMAD signaling.

Potential of Lyophilized Platelet Concentrates for Craniofacial Tissue Regenerative Therapies

Objective: The use of platelet concentrates (PCs) in oral and maxillofacial surgery, periodontology, and craniofacial surgery has been reported. While PCs provide a rich reservoir of autologous bioactive growth factors for tissue regeneration, their drawbacks include lack of utility for long-term application, low elastic modulus and strength, and limited storage capability. These issues restrict their broader application. This review focuses on the lyophilization of PCs (LPCs) and how this processing approach affects their biological and mechanical properties for application as a bioactive scaffold for craniofacial tissue regeneration. Materials and Methods: A comprehensive search of five electronic databases, including Medline, PubMed, EMBASE, Web of Science, and Scopus, was conducted from 1946 until 2019 using a combination of search terms relating to this topic. Results: Ten manuscripts were identified as being relevant. The use of LPCs was mostly studied in in vitro and in vivo craniofacial bone regeneration models. Notably, one clinical study reported the utility of LPCs for guided bone regeneration prior to dental implant placement. Conclusions: Lyophilization can enhance the inherent characteristics of PCs and extends shelf-life, enable their use in emergency surgery, and improve storage and transportation capabilities. In light of this, further preclinical studies and clinical trials are required, as LPCs offer a potential approach for clinical application in craniofacial tissue regeneration.

Tensile strength assay comparing the resistance between two different autologous platelet concentrates (leucocyte-platelet rich fibrin versus advanced-platelet rich fibrin): a pilot study

Background

Since the leucocyte-platelet rich fibrin (L-PRF) was published in 2001, many studies have been developed, analyzing its properties, and also verifying new possibilities to improve it. Thereby, it emerges the advanced-platelet rich fibrin (A-PRF) with a protocol that optimizes the properties obtained by the L-PRF. Nonetheless, there is a gap in the literature to landmark the evolutive process concerning the mechanical properties in specific the resistance to tensile strength which consequently may influence the time for membrane degradation. Thus, this study had the goal to compare the resistance to the traction of membranes produced with the original L-PRF and A-PRF protocols, being the first to this direct comparison.

Findings

The harvest of blood from a healthy single person, with no history of anticoagulant usage. We performed the protocols described in the literature, within a total of 13 membranes produced for each protocol (n = 26). Afterward, the membranes were prepared and submitted to a traction test assessing the maximal and the average traction achieved for each membrane. The data were analyzed statistically using the unpaired t test. Regarding average traction, A-PRF obtained a value of 0.0288 N mm⁻² and L-PRF 0.0192 N mm⁻² (p < 0.05 using unpaired t test). For maximal traction, A-PRF obtained 0.0752 N mm⁻² and L-PRF 0.0425 N mm⁻² (p < 0.05 using unpaired t test).

Conclusion

With this study, it was possible to conclude that indeed A-PRF has a significative higher maximal traction score and higher average traction compared to L-PRF, indicating that it had a higher resistance when two opposing forces are applied.

The distribution pattern and growth factor level in platelet-rich fibrin incorporated skin-derived mesenchymal stem cells: An in vitro study

Background and Aim:

A skin wound in an animal must be cared for to prevent further health issues. Platelet-rich fibrin (PRF) and skin-derived mesenchymal stem cells (SMSCs) have been reported to have potential in increasing the rate of wound healing. This study aimed to analyze the distribution patterns and levels of platelet-derived growth factor (PDGF), insulin-like growth factor (IGF), vascular endothelial growth factor (VEGF), and transforming growth factor-β (TGF-β) in PRF incorporated with SMSCs.

Materials and Methods:

This study employed a true experiment (in vitro) design with post-test only performed in the control group alone. PRF and SMSCs were extracted from the blood and skin of 16 rabbits. SMSCs were characterized using immunocytochemistry to examine clusters of differentiation for 45, 73, 90, and 105. PRF was incorporated into the SMSCs and then divided into four groups (N=32/n=8): Group A (PRF only), Group B (PRF+SMSCs, incubated for 1 day), Group C (PRF+SMSCs, incubated for 3 days), and Group D (PRF+SMSCs, incubated for 5 days). Scanning electron microscopy was used to examine the distribution pattern of SMSCs between groups. The supernatant serum (Group A) and supernatant medium culture (Group D) were collected for the measurement of PDGF, IGF, VEGF, and TGF-β using an enzyme-linked immunosorbent assay sandwich kit. An unpaired t-test was conducted to analyze the differences between Groups A and D (p<0.01).

Results:

Group D had the most morphologically visible SMSCs attached to the PRF, with elongated and pseudopodia cells. There was a significant difference between the levels of growth factor in Groups A and D (p=0.0001; p<0.01).

Conclusion:

SMSCs were able to adhere to and distribute evenly on the surface of PRF after 5 days of incubation. The PRF incorporated SMSCs contained high levels of PDGF, IGF, VEGF, and TGF- β, which may prove to have potential in enhancing wound healing.

Crosslinked Hyaluronic Acid Gels with Blood-Derived Protein Components for Soft Tissue Regeneration

Hyaluronic acid (HA) is an ideal initial material for preparing hydrogels, which may be used as scaffolds in soft tissue engineering based on their advantageous physical and biological properties. In this study, two crosslinking agents, divinyl sulfone (DVS) and butanediol diglycidyl ether, were used to investigate their effect on the properties of HA hydrogels. As HA hydrogels alone do not promote cell adhesion on the scaffold, fibrin and serum from platelet-rich fibrin (SPRF) were combined with the scaffold; the aim was to create a material intended to be used as soft tissue implant that facilitates new tissue formation, and degrades over time. The chemical changes were characterized and cell attachment capacity of the protein-containing gels was examined using human mesenchymal stem cells, and viability was assessed using live-dead staining. Fourier-transform infrared measurements revealed that linking fibrin into the gel was more effective than linking SPRF. The scaffolds were found to be able to support cell adherence onto the hydrogels, and the best result was achieved when HA was crosslinked with DVS and contained fibrin. The most promising derivative, 5% DVS-crosslinked fibrin-containing hydrogel, was injected subcutaneously into C57BL/6 mice for 12 weeks. The scaffold was proven to be biocompatible, remodeling, and vascularization occurred, while shape and integrity were maintained. Impact statement Fibrin was combined with crosslinked hyaluronic acid (HA) for regenerative application, the structure of the combination of crosslinked HA with blood-derived protein was analyzed and effective coating was proven. It was observed that the fibrin content led to better mesenchymal stem cell attachment in vitro. The compositions showed biocompatibility, connective tissue and vascularization took place when implanted in vivo. Thus, a biocompatible, injectable gel was produced, which is a potential candidate for soft tissue implantation.

Characterization and Chondroprotective Effects of Extracellular Vesicles From Plasma- and Serum-Based Autologous Blood-Derived Products for Osteoarthritis Therapy

Autologous blood products gain increasing interest in the field of regenerative medicine as well as in orthopedics, aesthetic surgery, and cosmetics. Currently, citrate-anticoagulated platelet-rich plasma (CPRP) preparations are often applied in osteoarthritis (OA), but more physiological and cell-free alternatives such as hyperacute serum (hypACT) are under development. Besides growth factors, blood products also bring along extracellular vesicles (EVs) packed with signal molecules, which open up a new level of complexity at evaluating the functional spectrum of blood products. Large proportions of EVs originated from platelets in CPRP and hypACT, whereas very low erythrocyte and monocyte-derived EVs were detected via flow cytometry. EV treatment of chondrocytes enhanced the expression of anabolic markers type II collagen, SRY-box transcription factor 9 (SOX9), and aggrecan compared to full blood products, but also the catabolic marker and tissue remodeling factor matrix metalloproteinase 3, whereas hypACT EVs prevented type I collagen expression. CPRP blood product increased SOX9 protein expression, in contrast to hypACT blood product. However, hypACT EVs induced SOX9 protein expression while preventing interleukin-6 secretion. The results indicate that blood EVs are sufficient to induce chondrogenic gene expression changes in OA chondrocytes, while preventing proinflammatory cytokine release compared to full blood product. This highlights the potential of autologous blood-derived EVs as regulators of cartilage extracellular matrix metabolism and inflammation, as well as candidates for new cell-free therapeutic approaches for OA.

Freeze-Drying of Platelet-Rich Plasma: The Quest for Standardization

The complex biology of platelets and their involvement in tissue repair and inflammation have inspired the development of platelet-rich plasma (PRP) therapies for a broad array of medical needs. However, clinical advances are hampered by the fact that PRP products, doses and treatment protocols are far from being standardized. Freeze-drying PRP (FD-PRP) preserves platelet function, cytokine concentration and functionality, and has been proposed as a consistent method for product standardization and fabrication of an off-the-shelf product with improved stability and readiness for future uses. Here, we present the current state of experimental and clinical FD-PRP research in the different medical areas in which PRP has potential to meet prevailing medical needs. A systematic search, according to PRISMA (Preferred Reported Items for Systematic Reviews and Meta-Analyses) guidelines, showed that research is mostly focused on wound healing, i.e., developing combination products for ulcer management. Injectable hydrogels are investigated for lumbar fusion and knee conditions. In dentistry, combination products permit slow kinetics of growth factor release and functionalized membranes for guided bone regeneration.

In vivo evaluation of the biocompatibility and biodegradation of a new denatured plasma membrane combined with liquid PRF (Alb-PRF)

Guided bone regeneration (GBR) is a process that involves the regeneration of bone defects through the application of occlusive membranes that mechanically exclude the population of non-osteogenic cells from the surrounding soft tissue. Interestingly, platelet-rich fibrin (PRF) has previously been proposed as an autologous GBR membrane despite its short-term resorption period of 2-3 weeks. Recent clinical observations have demonstrated that, by heating a liquid platelet-poor plasma (PPP) layer and mixing the cell-rich buffy coat zone, the resorption properties of heated albumin gel with liquid-PRF (Alb-PRF) can be significantly improved. The aim of this study was to evaluate the inflammatory reaction, biocompatibility, and extended degradation properties of a new autologous Alb-PRF membrane in comparison to commonly utilized standard PRF after nude mice implantation, according to ISO 10993-6/2016. Two standard preparations of PRF (L-PRF and H-PRF) were compared to novel Alb-PRF following subcutaneous implantation at 7, 14, and 21 days. All groups demonstrated excellent biocompatibility owing to their autologous sources. However, it is worth noting that, while both L-PRF and H-PRF membranes demonstrated significant or complete resorption by 21 days, the Alb-PRF membrane remained volume-stable throughout the duration of the study. This study demonstrates-for the first time, to the best of our knowledge-a marked improvement in the membrane stability of Alb-PRF. This indicates its future potential for use as a biological barrier membrane for GBR procedures with a long-lasting half-life, or as a biological filler material in esthetic medicine applications. Thus, further studies are warranted to explore future clinical applications in various fields of medicine.

A Practical Guide to Class IIa Medical Device Development

There are many beneficial medical device ideas based on clinical needs and laboratory research, but medical device development is an expensive, time-consuming and complex challenge. Research and quality management, which are both needed to develop a medical device, are two distinct fields, initiated by a researcher or a clinician having a concept for a medical device, and it is often challenging to find and achieve the proper steps to create a licensed product. Thus, in this paper, we demonstrate the required mindset and main steps of the medical device development procedure through an existing example, a Class IIa medical device, called hypACT Inject Auto. HypACT is a specific syringe, which is capable of blood drawing and serum from platelet-rich fibrin (SPRF) isolation in one step in a closed system. SPRF is intended to be used to improve joint functions in the case of musculoskeletal diseases, specifically osteoarthritis.

Biofunctionalization of porcine-derived collagen matrices with platelet rich fibrin: influence on angiogenesis in vitro and in vivo

Objectives

Porcine-derived collagen matrices (CM) can be used for oral tissue regeneration, but sufficient revascularization is crucial. The aim of this study was to analyze the influence of platelet-rich fibrin (PRF) on angiogenesis of different CM in vitro and in vivo.

Materials and methods

Three different CM (mucoderm, jason, collprotect) were combined with PRF in a plotting process. Growth factor release (VEGF, TGF-β) was measured in vitro via ELISA quantification after 1,4 and 7 days in comparison to PRF alone. In ovo yolk sac (YSM) and chorion allantois membrane (CAM) model, angiogenic potential were analyzed in vivo with light- and intravital fluorescence microscopy after 24 h, then verified with immunohistochemical staining for CD105 and αSMA.

Results

Highest growth factor release was seen after 24 h for all three activated membranes in comparison to the native CM (VEGF 24 h: each p < 0.05; TGF-β: each p < 0.001) and the PRF (no significant difference). All activated membranes revealed a significantly increased angiogenic potential in vivo after 24 h (vessels per mm2: each p < 0.05; branching points per mm2: each p < 0.01; vessel density: each p < 0.05) and with immunohistochemical staining for CD105 (each p < 0.01) and αSMA (each p < 0.05).

Conclusions

PRF improved the angiogenesis of CM in vitro and in vivo.

Clinical relevance

Bio-functionalization of CM with PRF could easily implemented in the clinical pathway and may lead to advanced soft tissue healing.

Investigation of Cytokine Changes in Osteoarthritic Knee Joint Tissues in Response to Hyperacute Serum Treatment

One option to fight joint degradation and inflammation in osteoarthritis is the injection of activated blood products into the synovial space. It has been demonstrated that hyperacute serum is the most proliferative among plasma products, so we investigated how the cytokine milieu of osteoarthritic knee joint reacts to hyperacute serum treatment in vitro. Cartilage, subchondral bone, and synovial membrane explanted from osteoarthritic knees were stimulated by interleukin-1 beta (IL-1β) and the concentration of 39 biomarkers was measured in the co-culture supernatant after hyperacute serum treatment. The IL-1β stimulation triggered a strong inflammatory response and enhanced the concentrations of matrix metalloproteinase 3 and 13 (MMP-3 and MMP-13), while hyperacute serum treatment reduced inflammation by decreasing the concentrations of IL-1β, tumor necrosis factor alpha (TNF-α), interleukin-6 receptor alpha (IL-6Rα), and by increasing the level of interleukin-1 antagonist (IL-1RA) Cell viability increased by day 5 in the presence of hyperacute serum. The level of MMPs-1, 2, and 9 were higher on day 3, but did not increase further until day 5. The concentrations of collagen 1 alpha 1 (COL1A1) and osteonectin were increased and receptor activator of nuclear factor kappa-B ligand (RANKL) was reduced in response to hyperacute serum. We concluded that hyperacute serum treatment induces cell proliferation of osteoarthritic joint tissues and affects the cytokine milieu towards a less inflamed state.

Influence of Fractionation Methods on Physical and Biological Properties of Injectable Platelet-Rich Fibrin: An Exploratory Study

Injectable platelet-rich fibrin (i-PRF) has been used as an autografting material to enhance bone regeneration through intrinsic growth factors. However, fractionation protocols used to prepare i-PRF can be varied and the effects of different fractionation protocols are not known. In this study, we investigated the influence of different fractions of i-PRF on the physical and biological properties derived from variations in i-PRF fractionation preparation. The i-PRF samples, obtained from the blood samples of 10 donors, were used to harvest i-PRF and were fractioned into two types. The yellow i-PRF fractionation was harvested from the upper yellow zone, while the red i-PRF fractionation was collected from both the yellow and red zone of the buffy coat. The viscoelastic property measurements, including the clot formation time, α-angle, and maximum clot firmness, were performed by rotational thromboelastometry. The fibrin network was examined using a scanning electron microscope. Furthermore, the concentration of growth factors released, including VEGF, TGF-β1, and PDGF, were quantified using ELISA. A paired t-test with a 95% confidence interval was used. All three viscoelastic properties were statistically significantly higher in the yellow i-PRF compared to the red i-PRF. The scanning electron microscope reviewed more cellular components in the red i-PRF compared to the yellow i-PRF. In addition, the fibrin network of the yellow i-PRF showed a higher density than that in the red i-PRF. There was no statistically significant difference between the concentration of VEGF and TGF-β1. However, at Day 7 and Day 14 PDGF concentrations were statistically significantly higher in the red i-PRF compared to the yellow group. In conclusion, these results showed that the red i-PRF provided better biological properties through the release of growth factors. On the other hand, the yellow i-PRF had greater viscoelastic physical properties. Further investigations into the appropriate i-PRF fractionation for certain surgical procedures are therefore necessary to clarify the suitability for each fraction for different types of regenerative therapy.

The Composition of Hyperacute Serum and Platelet-Rich Plasma Is Markedly Different despite the Similar Production Method

Autologous blood derived products, such as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) are widely applied in regenerative therapies, in contrast to the drawbacks in their application, mainly deriving from the preparation methods used. Eliminating the disadvantages of both PRP and PRF, hyperacute serum (HAS) opens a new path in autologous serum therapy showing similar or even improved regenerative potential at the same time. Despite the frequent experimental and clinical use of PRP and HAS, their protein composition has not been examined thoroughly yet. Thus, we investigated and compared the composition of HAS, serum, PRP and plasma products using citrate and EDTA by simple laboratory tests, and we compared the composition of HAS, serum, EDTA PRP and plasma by Proteome Profiler and ELISA assays. According to our results the natural ionic balance was upset in both EDTA and citrate PRP as well as in plasma. EDTA PRP contained significantly higher level of growth factors and cytokines, especially platelet derived angiogenic and inflammatory proteins, that can be explained by the significantly higher number of platelets in EDTA PRP. The composition analysis of blood derivatives revealed that although the preparation method of PRP and HAS were similar, the ionic and protein composition of HAS could be advantageous for cell function.