Cell Attachment Research Articles

Assessing Microstructural, Biomechanical, and Biocompatible Properties of TiNb Alloys for Potential Use as Load-Bearing Implants.

Titanium-Niobium (TiNb) alloys are commonly employed in a number of implantable devices, yet concerns exist regarding their use in implantology owing to the biomechanical mismatch between the implant and the host tissue. Therefore, to balance the mechanical performance of the load-bearing implant with bone, TiNb alloys with differing porosities were fabricated by powder metallurgy combined with spacer material. Microstructures and phase constituents were characterized with energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The mechanical properties were tested by uniaxial compression, and the corrosion performance was determined via a potentiodynamic polarization experiment. To evaluate a highly matched potential implant with the host, biocompatibilities such as cell viability and proliferation rate, fibronectin adsorption, plasmid-DNA interaction, and an SEM micrograph showing the cell morphology were examined in detail. The results showed that the alloys displayed open and closed pores with a uniform pore size and distribution, which allowed for cell adherence and other cellular activities. The alloys with low porosity displayed compressive strength between 618 MPa and 1295 MPa, while the alloys with high porosity showed significantly lower strength, ranging from 48 MPa to 331 MPa. The biological evaluation of the alloys demonstrated good cell attachment and proliferation rates.

Talin2 binds to non-muscle myosin IIa and regulates cell attachment and fibronectin secretion

Talin2 is localized to large focal adhesions and is indispensable for traction force generation, invadopodium formation, cell invasion as well as metastasis. Talin2 has a higher affinity toward β-integrin tails than talin1. Moreover, disruption of the talin2-β-integrin interaction inhibits traction force generation, invadopodium formation and cell invasion, indicating that a strong talin2-β-integrin interaction is required for talin2 to fulfill these functions. Nevertheless, the role of talin2 in mediation of these processes remains unknown. Here we show that talin2 binds to the N-terminus of non-muscle myosin IIA (NMIIA) through its F3 subdomain. Moreover, talin2 co-localizes with NMIIA at cell edges as well as at some cytoplasmic spots. Talin2 also co-localizes with cortactin, an invadopodium marker. Furthermore, overexpression of NMIIA promoted the talin2 head binding to the β1-integrin tail, whereas knockdown of NMIIA reduced fibronectin and matrix metalloproteinase secretion as well as inhibited cell attachment on fibronectin-coated substrates. These results suggest that talin2 binds to NMIIA to control the secretion of extracellular matrix proteins and this interaction modulates cell adhesion.

Bioactive Glial-Derived Neurotrophic Factor from a Safe Injectable Collagen-Alginate Composite Gel Rescues Retinal Photoreceptors from Retinal Degeneration in Rabbits.

The management of vision-threatening retinal diseases remains challenging due to the lack of an effective drug delivery system. Encapsulated cell therapy (ECT) offers a promising approach for the continuous delivery of therapeutic agents without the need for immunosuppressants. In this context, an injectable and terminable collagen-alginate composite (CAC) ECT gel, designed with a Tet-on pro-caspase-8 system, was developed as a safe intraocular drug delivery platform for the sustained release of glial-cell-line-derived neurotrophic factor (GDNF) to treat retinal degenerative diseases. This study examined the potential clinical application of the CAC ECT gel, focusing on its safety, performance, and termination through doxycycline (Dox) administration in the eyes of healthy New Zealand White rabbits, as well as its therapeutic efficacy in rabbits with sodium-iodate (SI)-induced retinal degeneration. The findings indicated that the CAC ECT gel can be safely implanted without harming the retina or lens, displaying resistance to degradation, facilitating cell attachment, and secreting bioactive GDNF. Furthermore, the GDNF levels could be modulated by the number of implants. Moreover, Dox administration was effective in terminating gel function without causing retinal damage. Notably, rabbits with retinal degeneration treated with the gels exhibited significant functional recovery in both a-wave and b-wave amplitudes and showed remarkable efficacy in reducing photoreceptor apoptosis. Given its biocompatibility, mechanical stability, controlled drug release, terminability, and therapeutic effectiveness, our CAC ECT gel presents a promising therapeutic strategy for various retinal diseases in a clinical setting, eliminating the need for immunosuppressants.

Dystroglycan-HSPG interactions provide synaptic plasticity and specificity.

This study examined the roles of the laminin and proteoglycan receptor dystroglycan (DG) in extracellular matrix stabilization and cellular mechanosensory processes conveyed through communication between the extracellular matrix (ECM) and cytoskeleton facilitated by DG. Specific functional attributes of HS-proteoglycans (HSPGs) are conveyed through interactions with DG and provide synaptic specificity through diverse interactions with an extensive range of cell attachment and adaptor proteins which convey synaptic plasticity. HSPG-DG interactions are important in phototransduction and neurotransduction and facilitate retinal bipolar-photoreceptor neuronal signaling in vision. Besides synaptic stabilization, HSPG-DG interactions also stabilize basement membranes and the ECM and have specific roles in the assembly and function of the neuromuscular junction. This provides neuromuscular control of muscle systems that control conscious body movement as well as essential autonomic control of diaphragm, intercostal and abdominal muscles and muscle systems in the face, mouth and pharynx which assist in breathing processes. DG is thus a multifunctional cell regulatory glycoprotein receptor and regulates a diverse range of biological and physiological processes throughout the human body. The unique glycosylation of the αDG domain is responsible for its diverse interactions with ECM components in cell-ECM signaling. Cytoskeletal cell regulatory switches assembled by the βDG domain in its role as a nuclear scaffolding protein respond to such ECM cues to regulate cellular behavior and tissue homeostasis thus DG has fascinating and diverse roles in health and disease.

Extruded plant protein two-dimensional scaffold structures support myoblast cell growth for potential applications in cultured meat

Cultured meat has been proposed as a promising alternative to conventional meat products. Five different plant protein blends made from soy (from two different manufacturers), wheat, mung bean, and faba bean, were extruded to form low-moisture meat analogs (LMMA) and were used to assess LMMA scaffold potential for cultured meat application. Extruded LMMAs were characterized using scanning electron microscopy, water-holding capacity, total soluble matter, and mechanical properties. Two-dimensional LMMA scaffolds were seeded with C2C12 skeletal myoblast cells and cultured for 14 days, and cell attachment and morphology were evaluated. All five extrudates exhibited directionality of their fibrous protein structures but to varying degrees. Soy, wheat, mung bean, and faba bean-based LMMA scaffolds initially supported myoblast cell growth. However, after 14 days of culture, the extruded wheat LMMA exhibited superior myoblast cell growth. This may be attributed to the highly aligned fibrous structure of the extruded wheat LMMA as well as its elastic modulus, which closely approximated that of native skeletal muscle. Overall, two-dimensional structures of the extruded plant proteins support cell growth and advance the development of cultured meat.

Converting ocean nacre into bone mineral matrix composite for bone regeneration- in vitro and in vivo studies

Nacre of Pinctada maxima is a natural biomineralized matrix, appeared 7 million years before hominins. In this study, we converted nacre into a self-setting particle bound with multiple calcium orthophosphates that reassemble mammals’ bone mineral matrices for induction of bone regeneration. The nacre-based calcium orthophosphates composite (NCOC) exhibited a compression strength of 10 MPa, which is superior to human trabecular bone. In vitro bioactivity tests revealed the formation of apatite with nano-porous flake-like crystals on the composite surface that mimic HA structure of a human bone matrix. NCOC demonstrated efficient attachment and proliferation of osteoblast cells, promoting osteogenic differentiation by increasing expressions of RUNX2 and OPN. In vivo studies using rabbit back fascia demonstrated that NCOC displays better bone healing and biocompatibility than conventional bone substitute apatite in critical bone defect models. The degradation of calcium carbonate crystal in vivo does not compromise structural integrity of NCOC. Overall, our data showed that NCOC produced through self-setting reactions, presents advantages such as accelerated biodegradation and osteostimulative properties, making it a promising bone substitute for effective bone regeneration.

Enhanced wound healing properties of biodegradable PCL/alginate core-shell nanofibers containing Salvia abrotanoides essential oil and ZnO nanoparticles

Electrospun nanofibrous membranes, with their unique structural features, can potentially enhance wound healing through controlled delivery of active agents. Here, an innovative porous nanofibrous membrane was developed as a dressing patch with antibacterial and anti-inflammatory functionalities for cutaneous wound healing. Zinc oxide nanoparticles (ZnO NPs) and Salvia abrotanoides essential oil (SAEO) were incorporated into sodium alginate, which served as the shell. Poly(ε-caprolactone) was used as the core of coaxial electrospun wound dressing nanofibers (PCL/SA@ZnO/SAEO). With the addition of ZnO NPs and SAEO, the average diameter of nanofibers was 187 ± 51 nm, with improved tensile strength (4.7 ± 0.4 MPa), elongation at break (32.9 ± 2.1), and elastic modulus (21.4 ± 2.0). Concurrent application of ZnO NPs and SAEO increased antimicrobial activity against Staphylococcus aureus and Escherichia coli and promoted the proliferation, attachment, and viability (>90 %) of L929 cells. The PCL/SA@ZnO/SAEO scaffold accelerated the healing time with total wound healing over 14 days in mouse models carrying full-thickness wounds compared to the nanofibrous scaffold without additives. Histopathological examinations demonstrated better tissue regeneration, i.e., enhanced collagen deposition, improved re-epithelialization, and neovascularization, and increased quantity of hair follicles. Moreover, the chicken chorioallantoic membrane assay confirmed the synergistic angiogenic effects of SAEO and ZnO NPs. Finally, the in vitro and in vivo results proposed the bioactive core-shell nanofibers synthesized as encouraging wound dressing materials for hastening the healing of cutaneous wounds.

Structural, mechanical, corrosion, and early biological assessment of tantalum nitride coatings deposited by reactive HiTUS

This study examined microstructure, mechanical, corrosion properties and initial biological evaluation of the tantalum nitride (Ta-xN, where x – nitrogen flow rate during deposition) coatings prepared by reactive High Utilization Sputtering (HiTUS) at various nitrogen flow rates (x = 0, 2, 4, 6, and 8 sccm). Coatings were deposited on a novel Mg alloy (Mgbal.-Zn0.9-Y2.05-Al0.25 at. %) containing long-period stacking ordered (LPSO) phases. The coatings' structure was analyzed using a combination of SEM/FIB/TEM techniques, while XRD determined the phase composition. The mechanical parameters investigated included hardness, indentation modulus, and scratch behavior. The corrosion resistance of the coatings with respect to the bare substrate was evaluated in chloride-containing solutions. The wettability and early biological assessment of the coatings were also examined. The phase evolution strongly influenced the hardness and indentation modulus. The Ta-xN coatings made at x = 2 sccm nitrogen corresponding to HCP-Ta2N exhibited the highest hardness and indentation modulus. An increase in nitrogen flow rates resulted in the formation of FCC structure with slightly reduced hardness and indentation modulus. In addition, Ta-xN coatings (x ≥ 4sccm) showed superior corrosion resistance compared to BCC structured α-Ta, enhancing the corrosion performance of the Mg-LPSO bulk substrate. Finally, at the early incubation stage (24 h), L929 fibroblasts exhibited better cell attachment to the Ta-6N coating than to the bare Mg-LPSO substrate.

Biofunctionalization of Cellulose Microcarriers Using a Carbohydrate Binding Module Linked with Fibroblast Growth Factor for the Expansion of Human Umbilical Mesenchymal Stromal Cells in Stirred Suspension Bioreactors.

Mesenchymal stromal cells (MSCs) have the potential to be used as autologous or allogenic cell therapy in several diseases due to their beneficial secretome and capacity for immunomodulation and differentiation. However, clinical trials using MSCs require a large number of cells. As an alternative to traditional culture flasks, suspension bioreactors provide a scalable platform to produce clinically relevant quantities of cells. When cultured in bioreactors, anchorage-dependent cells like MSCs require the addition of microcarriers, which provide a surface for cell attachment while in suspension. The best performing microcarriers are typically coated in animal derived proteins, which increases cellular attachment and proliferation but present issues from a regulatory perspective. To overcome this issue, a recombinant fusion protein was generated linking basic fibroblast growth factor (bFGF) to a cellulose-specific carbohydrate binding module (CBM) and used to functionalize the surface of cellulose microcarriers for the expansion of human umbilical MSCs in suspension bioreactors. The fusion protein was shown to support the growth of MSCs when used as a soluble growth factor in the absence of cellulose, readily bound to cellulose microcarriers in a dose-dependent manner, and ultimately improved the expansion of MSCs when grown in bioreactors using cellulose microcarriers. The use of CBM fusion proteins offers a simple method for the surface immobilization of growth factors to animal component-free substrates such as cellulose, which can be used alongside bioreactors to increase growth factor lifespan, decrease culture medium cost, and increase cell production in the manufacturing of therapeutic cells.

Innovative Bioscaffolds in Stem Cell and Regenerative Therapies for Corneal Pathologies.

Corneal diseases, which can result in substantial visual impairment and loss of vision, are an important worldwide health issue. The aim of this review was to investigate the novel application of bioscaffolds in stem cell and regenerative treatments for the treatment of corneal disorders. The current literature reports that organic and artificial substances create bioscaffolds that imitate the inherent structure of the cornea, facilitating the attachment, growth, and specialization of stem cells. Sophisticated methods such as electrospinning, 3D bioprinting, and surface modification have been reported to enhance the characteristics of the scaffold. These bioscaffolds have been shown to greatly improve the survival of stem cells and facilitate the regrowth of corneal tissue in both laboratory and live animal experiments. In addition, the incorporation of growth factors and bioactive compounds within the scaffolds can promote a favorable milieu for corneal regeneration. To summarize, the advancement of these groundbreaking bioscaffolds presents a hopeful treatment strategy for the regeneration of the cornea, which has the potential to enhance the results for individuals suffering from corneal disorders. This study highlights the possibility of utilizing the fields of biomaterials science and stem cell treatment to tackle medical demands that have not yet been satisfied in the field of ophthalmology.

Influence of Copper on Oleidesulfovibrio alaskensis G20 Biofilm Formation.

Copper is known to have toxic effects on bacterial growth. This study aimed to determine the influence of copper ions on Oleidesulfovibrio alaskensis G20 biofilm formation in a lactate-C medium supplemented with variable copper ion concentrations. OA G20, when grown in media supplemented with high copper ion concentrations of 5, 15, and 30 µM, exhibited inhibited growth in its planktonic state. Conversely, under similar copper concentrations, OA G20 demonstrated enhanced biofilm formation on glass coupons. Microscopic studies revealed that biofilms exposed to copper stress demonstrated a change in cellular morphology and more accumulation of carbohydrates and proteins than controls. Consistent with these findings, sulfur (dsrA, dsrB, sat, aprA) and electron transport (NiFeSe, NiFe, ldh, cyt3) genes, polysaccharide synthesis (poI), and genes involved in stress response (sodB) were significantly upregulated in copper-induced biofilms, while genes (ftsZ, ftsA, ftsQ) related to cellular division were negatively regulated compared to controls. These results indicate that the presence of copper ions triggers alterations in cellular morphology and gene expression levels in OA G20, impacting cell attachment and EPS production. This adaptation, characterized by increased biofilm formation, represents a crucial strategy employed by OA G20 to resist metal ion stress.

Fabrication and Temporal Dependency Osteogenic Regulation of Dual-Scale Hierarchical Microstructures on Medical Metal Surface.

The structural characteristics at the interface of bone implants can guide biological regulation. In this study, a dual-scale hierarchical microstructure is proposed and customized using hybrid machining to achieve temporal dependency osteogenic regulation. It is observed that osteoblasts induced by dual-scale hierarchical structure exhibit adequate protrusion development and rapid cell attachment through the modulation of mechanical forces in the cell growth environment, and further promot the upregulation of the cell membrane receptor PDGFR-α, which is related to cell proliferation. Afterward, transcriptomic analysis reveals that during the differentiation stage, the DSH structure regulates cellular signaling cascades primarily through integrin adhesion mechanisms and then accelerates osteogenic differentiation by activating the TGF-β pathway and cAMP signaling pathway. Furthermore, the calcium nodules are preferentially deposited within the lower honeycomb-like channels, thereby endowing the proposed dual-scale hierarchical structure with the potential to induce oriented deposition and improve the long-term stability of the implant.

In Situ Live Monitoring of Extracellular Acidosis near Cancer Cells Using Digital Microfluidics with an Integrated Optical pH Sensor Film.

We demonstrate the live monitoring of extracellular acidification on digital microfluidics using a chip-integrated fluorescent pH sensor film. The metabolism of various types of live cells including cancer and healthy cells were investigated through recording the extracellular pH (pHe) change. An optical pH sensor array was integrated onto a digital microfluidic (DMF) interface with a diameter of 2 mm per pH-sensing spot. Miniaturized, label-free, and noninvasive monitoring of extracellular acidosis on DMF was realized within a pH range of 5.0-8.0 with good sensitivity and rapid response. The pH sensitive probe fluorescein-5-isothiocyanate was covalently bound to poly-2-hydroxyethyl methacrylate and immobilized on a circularly exposed indium tin oxide interface on the DMF top plate. The surface of the fabricated pH sensor spots was modified with polydopamine via self-polymerization. Direct cell attachment on the sensor surfaces enabled rapid pH detection near the cell membranes. Automatic medium exchange on cell-attached pH sensing sites was achieved though solution passive dispensing on DMF. The developed DMF platform was used to monitor the pHe decrease during MCF-7 and A549 cancer cell proliferation due to abnormal glycolysis metabolism. A rapid pH decrease at the pH sensing area in the presence of cancer cells could be detected within 2 min after fresh medium exchange, while no obvious pHe change was observed with HUVEC healthy cells. Real-time detection of cell acidification and cellular response to different metabolic conditions such as higher glucose levels or administered anticancer drugs was possible.

Antibiotic susceptibility and biofilm forming ability of Staphylococcus aureus isolated from Jordanian patients with diabetic foot ulcer.

Microbial biofilm is characterized by the irreversible attachment of planktonic cells to a surface and is usually associated with high antimicrobial resistance with worsening the wound healing. The objective of the study was to determine the prevalence of Staphylococcus aureus in diabetic foot ulcers (DFUs) of diabetic patients and to investigate antibiotic susceptibility patterns of these isolates. In addition to screen biofilm forming ability of isolated S. aureus. A total of 112 non-healing wound swabs of diabetic foot patients were collected and cultured on different culture media to identify and characterize 98 isolates. The S. aureus isolates were examined for their antibiotic susceptibility to different antimicrobial agents. Furthermore, S. aureus isolates were evaluated for their biofilm production capability using the Tissue Culture Plate Method (TPC). The level of icaA gene expression was determined by RT-PCR. The results of this study showed that these non-healing wounds yield positive cultures, with an average of 1.67 organisms per sample. The isolates showed highest resistance against oxacillin (95.2%) and lowest resistance against linezolid (3.7%). All isolates were biofilm producers and a significant association with the icaA gene expression level was recorded. This study showed that S. aureus isolates have a great ability to produce biofilms that are associated with the chronicity of wounds in diabetic patients. Routine screening for biofilm formers in chronic wounds and their antibiotic susceptibility testing will help in early treatment and prevent any other complications.

Biomaterial Scaffolds for Periodontal Tissue Engineering.

Advanced periodontitis poses a significant threat to oral health, causing extensive damage and loss of both hard and soft periodontal tissues. While traditional therapies such as scaling and root planing can effectively halt the disease's progression, they often fail to fully restore the original architecture and function of periodontal tissues due to the limited capacity for spontaneous regeneration. To address this challenge, periodontal tissue engineering has emerged as a promising approach. This technology centers on the utilization of biomaterial scaffolds, which function as three-dimensional (3D) templates or frameworks, supporting and guiding the regeneration of periodontal tissues, including the periodontal ligament, cementum, alveolar bone, and gingival tissue. These scaffolds mimic the extracellular matrix (ECM) of native periodontal tissues, aiming to foster cell attachment, proliferation, differentiation, and, ultimately, the formation of new, functional periodontal structures. Despite the inherent challenges associated with preclinical testing, the intensification of research on biomaterial scaffolds, coupled with the continuous advancement of fabrication technology, leads us to anticipate a significant expansion in their application for periodontal tissue regeneration. This review comprehensively covers the recent advancements in biomaterial scaffolds engineered specifically for periodontal tissue regeneration, aiming to provide insights into the current state of the field and potential directions for future research.

Surface transformed magnesium alloy: Investigating the in-vitro degradation consequences of rare-earth bioactive coatings

Rare-earth elements dominate both the industrial and the medical fields. Recent advancements in assisted bone healing implant research have sparked a revolution emphasising the exploration of new materials and customized applications with simplified methodology. In line with this trend, our study introduces an approach by applying a rare-earth element, terbium, as a coating on magnesium alloy implants. The in-vitro behaviour of the coated implants was systematically evaluated based on the duration of the coating formation and optimised. The TCC-30 coating started to degrade beyond the optimised duration of conversion. The resulting coating exhibited a distinctive nanolamellar structure on the surface, which transformed into a flower-like morphology as it matured. The chemical profiling of the coating with XPS confirmed the presence of elements including Tb, O and Mg. The mineralizing ability was examined with simulated body fluid (SBF) and Dulbecco's Modified Eagle Medium (DMEM) was found to possess nano-agglomerate structure in the form of clusters and coral-like morphology with nano petals structure, respectively. Further exploration of the biological behaviour including monitoring cell attachment and proliferation demonstrated enhancement. This innovative approach holds promise for enhancing the performance and biocompatibility of magnesium alloy implants, marking a significant stride in the ongoing evolution of assisted bone healing technologies.

3D Bioprinting with Visible Light Cross-Linkable Mucin-Hyaluronic Acid Composite Bioink for Lung Tissue Engineering.

3D printing can revolutionize personalized medicine by allowing cost-effective, customized tissue-engineering constructs. However, the limited availability and diversity of biopolymeric hydrogels restrict the variety and applications of bioinks. In this study, we introduce a composite bioink for 3D bioprinting, combining a photo-cross-linkable derivative of Mucin (Mu) called Methacrylated Mucin (MuMA) and Hyaluronic acid (HA). The less explored Mucin is responsible for the hydrogel nature of mucus and holds the potential to be used as a bioink material because of its plethora of features. HA, a crucial extracellular matrix component, is mucoadhesive and enhances ink viscosity and printability. Photo-cross-linking with 405 nm light stabilizes the printed scaffolds without damaging cells. Rheological tests reveal shear-thinning behavior, aiding cell protection during printing and improved MuMA bioink viscosity by adding HA. The printed structures exhibited porous behavior conducive to nutrient transport and cell migration. After 4 weeks in phosphate-buffered saline, the scaffolds retain 70% of their mass, highlighting stability. Biocompatibility tests with lung epithelial cells (L-132) confirm cell attachment and growth, suggesting suitability for lung tissue engineering. It is envisioned that the versatility of bioink could lead to significant advancements in lung tissue engineering and various other biomedical applications.

Amino acid surface modified bioglass: A candidate biomaterial for bone tissue engineering1.

Bioglasses are solid materials consisted of sodium oxide, calcium oxide, silicon dioxide and phosphorus in various proportions and have used in bone tissue engineering. There have been ongoing efforts to improve the surface properties of bioglasses to increase biocompatibility and performance. The aim of the present study is to modify the bioglass surface with an amino acid mixture consisting of arginine, aspartic acid, phenylalanine, cysteine, histidine and lysine, to characterize the surface, and to evaluate the performance and biocompatibility in vitro and in vivo. The untreated bioglass, bioglass kept in simulated body fluid (SBF), and modified bioglass were used in further evaluation. After confirmation of the surface modification with FT-IR analyses and SEM analyses, MC3T3-E1 preosteoblasts adhesion on the surface was also revealed by SEM. The modified bioglass had significantly higher ALP activity in colorimetric measurement, rate of calcium accumulations in Alizarin red s staining, lower rate of cell death in Annexin-V/PI staining to determine apoptosis and necrosis. Having higher cell viability rate in MTT test and absence of genotoxicity in micronucleus test (OECD 487), the modified bioglass was further confirmed for biocompatibility in vitro. The results of the rat tibial defect model revealed that the all bioglass treatments had a significantly better bone healing score compared to the untreated negative control. However, the modified bioglass exhibited significantly better bone healing efforts especially during the first and the second months compared to the other bioglass treatment treatments. As a result, the amino acid surface modification of bioglasses improves the surface biocompatibility and osteogenic performance that makes the amino acid modified bioglass a better candidate for bone tissue engineering. RESEARCH HIGHLIGHTS: Bioglass surface modification with amino acids contributes to bioglass-tissue interaction with an improved cell attachment. Modified bioglass increases in vitro Alp activity and calcium accumulation, and also positively affects cell behavior by supporting cell adaptation. Bioglass exerts osteogenic potential in vivo especially during early bone healing.

Reinforcing β-tricalcium phosphate scaffolds for potential applications in bone tissue engineering: impact of functionalized multi-walled carbon nanotubes

Beta-tricalcium phosphate (β-TCP) scaffolds manufactured through the foam replication method are widely employed in bone tissue regeneration. The mechanical strength of these scaffolds is a significant challenge, partly due to the rheological properties of the original suspension. Various strategies have been explored to enhance the mechanical properties. In this research, β-TCP scaffolds containing varying concentrations (0.25–1.00 wt%) of multi-walled carbon nanotubes (MWCNT) were developed. The findings indicate that the addition of MWCNTs led to a concentration-dependent improvement in the viscosity of β-TCP suspensions. All the prepared slurries exhibited viscoelastic behavior, with the storage modulus surpassing the loss modulus. The three time interval tests revealed that MWCNT-incorporated β-TCP suspensions exhibited faster structural recovery compared to pure β-TCP slurries. Introducing MWCNT modified compressive strength, and the optimal improvement was obtained using 0.75 wt% MWCNT. The in vitro degradation of β-TCP was also reduced by incorporating MWCNT. While the inclusion of carbon nanotubes had a marginal negative impact on the viability and attachment of MC3T3-E1 cells, the number of viable cells remained above 70% of the control group. Additionally, the results demonstrated that the scaffold increased the expression level of osteocalcin, osteoponthin, and alkaline phosphatase genes of adiposed-derived stem cells; however, higher levels of gene expersion were obtained by using MWCNT. The suitability of MWCNT-modified β-TCP suspensions for the foam replication method can be assessed by evaluating their rheological behavior, aiding in determining the critical additive concentration necessary for a successful coating process.

Co-assembling bioactive short peptide nanofibers coated silk scaffolds induce neurite outgrowth of PC12 cells

Controlling biomolecular-cell interactions is crucial for the design of scaffolds for tissue engineering (TE). Regenerated silk fibroin (RSF) has been extensively used as TE scaffolds, however, RSF showed poor attachment of neuronal cells, such as rat pheochromocytoma (PC12) cells. In this work, amphiphilic peptides containing a hydrophobic isoleucine tail (I3) and laminin or fibronectin derived peptides (IKVAV, PDSGR, YIGSR, RGDS and PHSRN) were designed for promoting scaffold-cell interaction. Three of them (I3KVAV, I3RGDS and I3YIGSR) can self-assemble into nanofibers, therefore, were used to enhance the application of RSF in neuron TE. Live / dead assays revealed that the peptides exhibited negligible cytotoxicity against PC12 cells. The specific interaction between PC12 cells and the peptides were investigate using atomic force microscopy (AFM). The results indicated a synergistic effect in the designed peptides, promoting cellular attachment, proliferation and morphology changes. In addition, AFM results showed that co-assembling peptides I3KVAV and I3YIGSR possesses the best regulation of proliferation and attachment of PC12 cells, consistent with immunofluorescence staining results. Moreover, cell culture with hydrogels revealed that a mixture of peptides I3KVAV and I3YIGSR can also promote 3D neurites outgrowth. The approach of combining two different self-assembling peptides shows great potential for nerve regeneration applications.